ABSTRACT 
 
 
Title of Thesis: ASSESSMENT OF PACKAGING MEDIA 
USED IN LONG-TERM STORAGE OF 
ELECTRONIC COMPONENTS  
  
 Suraj Ravimanalan, 
Master of Science, 2021 
  
Thesis Directed By: Dr. Diganta Das 
Department of Mechanical Engineering 
 
Companies that produce end-products with long-term sustainment requirements 
undertake long-term storage as one of the measures to overcome the problem of 
electronic component obsolescence. To protect the components from environmental 
degradation during storage, they are packed inside vacuum sealed moisture barrier bags 
along with desiccants and humidity indicator cards. The desiccants have a specific 
adsorption capacity at a particular temperature / relative humidity condition. They 
cannot absorb the moisture permeated through the moisture barrier bag beyond that 
capacity. The relative humidity inside the moisture barrier bag also changes during 
long-term storage. This thesis provides a methodology to estimate the time to reach the 
desiccant's adsorption capacity and to estimate the increase in relative humidity inside 
the moisture barrier bag. The methodology is based on the experimental results and the 
first principle physical equations used for moisture permeation and adsorption. Based 
on these estimations, companies can decide on replacement schedules for moisture 
barrier bags and desiccants, thus protecting the electronic components contained within 
moisture barrier bags from humidity-related reliability issues.  
 
 
 
 
 
 
 
 
 
 
 
 
ASSESSMENT OF PACKAGING MEDIA USED FOR LONG-TERM 
STORAGE OF ELECTRONIC COMPONENTS 
 
 
 
by 
 
 
Suraj Ravimanalan 
 
 
 
 
 
Thesis submitted to the Faculty of the Graduate School of the  
University of Maryland, College Park, in partial fulfillment 
of the requirements for the degree of 
Master of Science 
2021 
 
 
 
 
 
 
Advisory Committee: 
Dr. Diganta Das, Chair 
Professor Peter Sandborn 
Professor Patrick McCluskey 
Dr. Michael Azarian 
Dr. Robert Kinyanjui 
 
 
Acknowledgements 
 
I would first like to thank my thesis advisor Dr. Diganta Das of Mechanical 
Engineering Dept. at University of Maryland, College Park for his continued guidance, 
support and for all the opportunities I was given to conduct my research. I would also like 
to thank Prof. Michael Pecht and Dr. Michael Azarian of Center for Advanced Life Cycle 
Engineering, University of Maryland, College Park for their insightful comments and 
valuable feedback.  
 
I would like to take this moment to thank Dr. Robert Kinyanjui of John Deere for 
sharing his expertise, and sincere and valuable guidance for this research. 
 
Finally, I must express my very profound gratitude to my parents and to my friends for 
their wise counsel, unfailing support, and continuous encouragement throughout my years 
of study. This accomplishment would not have been possible without them. 
 
  
ii 
 
 
Table of Contents 
Acknowledgements ....................................................................................................... ii 
Table of Contents ......................................................................................................... iii 
List of Tables ................................................................................................................ v 
List of Figures .............................................................................................................. vi 
Chapter 1: Introduction ................................................................................................. 1 
Chapter 2: Review of Standards and Prior Work on Long-Term Storage .................... 6 
JEDEC JEP 160 Standard ......................................................................................... 6 
GEIA-STD-0003A Standard ..................................................................................... 8 
IEC 62435 Standard ................................................................................................ 11 
Long-Term Storage Study by Texas Instruments ................................................... 11 
Chapter 3: Materials and its Properties ....................................................................... 13 
Moisture Barrier Bags ............................................................................................. 13 
Manufacturer Provided Information .................................................................... 13 
Construction of MBB .......................................................................................... 14 
Moisture Permeation Property of MBB - Permeability ....................................... 16 
Electrostatic Discharge (ESD) Protection Property ? Surface Resistivity .......... 20 
Carriers .................................................................................................................... 21 
Manufacturer Provided Information .................................................................... 23 
Material Composition Information ...................................................................... 24 
Electrostatic Discharge Protection Property of Carriers ? Surface Resistivity ... 24 
Mechanical Properties of the carriers .................................................................. 26 
Tensile Strength ....................................................................................................... 26 
Desiccants ................................................................................................................ 29 
Chapter 4: Degradation Mechanisms of Replaceable Elements ................................. 34 
Moisture Barrier Bags ............................................................................................. 34 
Degradation of Adhered Layer of Heat Seal ....................................................... 34 
Degradation of Static Dissipative Layer .............................................................. 35 
Carrier Tape of Tape and Reel ................................................................................ 36 
Polymeric Shrinkage ........................................................................................... 37 
Degradation of Static Dissipative Layer .............................................................. 38 
Cover Tape of Tape and Reel ? Degradation of Adhesive Layer ........................... 39 
Chapter 5: Experiments and Results ........................................................................... 43 
Experiments for Determining RH Inside MBB vs. Time ........................................ 43 
Equipment Used in the Experiment - Vacuum Sealing Machine ........................ 43 
Equipment Used in the Experiment - Wireless Temperature/RH Sensor ........... 49 
Determination of Accelerated Test Conditions ................................................... 50 
Experiment Procedure for Accelerated Aging of MBBs ..................................... 58 
Accelerated Aging Experiment for Change in Surface Resistivity ......................... 69 
Accelerated Aging Experiment for Change in Dimensions of Carrier Tape .......... 79 
Chapter 6: Discussion ................................................................................................. 86 
Method for Obtaining the Mass of Water Vapor Adsorbed by Desiccant vs. Time 86 
iii 
 
 
Method for Estimating the RH Inside MBB vs. Time ............................................ 88 
Chapter 7: Conclusions ............................................................................................... 96 
Chapter 8: Appendices ................................................................................................ 99 
Appendix A ? Elements of Long-Term Storage System ......................................... 99 
Carriers ................................................................................................................ 99 
Humidity Indicator Cards .................................................................................. 107 
Appendix B ? Material Property Testing, Analysis and Validation ..................... 110 
Moisture Barrier Bag ......................................................................................... 110 
Appendix C ? Calibration Information of the Equipment ..................................... 116 
Weighing Scale .................................................................................................. 116 
Temperature/Relative Humidity Chamber ........................................................ 116 
Chapter 9: References ............................................................................................... 118 
 
  
iv 
 
 
List of Tables 
Table 1 Long-Term Storage Standards for Electronic Components ............................. 6 
Table 2 Packing requirement for the protection level mentioned in SAE GEIA-STD-
0003A standard ........................................................................................................... 10 
Table 3 Properties of the MBB as provided by the manufacturer [11] ....................... 15 
Table 4 Calculated values of MVTR at different temperature / RH conditions ......... 19 
Table 5 Calculated values of constants ? a and b in equation (6) ............................... 20 
Table 6 Comparison of MVTR values calculated based on linear assumption and 
calculated by substituting the obtained the constants - a and b in equation (7) .......... 20 
Table 7 Calculated permeability values at temperatures - 60 ?C and 40 ?C ............... 20 
Table 8 Manufacturer information of the tape and reel carriers used in this thesis .... 23 
Table 9 Material composition information of Advantek PS+C carrier tape [22] ....... 24 
Table 10 Material composition information of Cpak-PS-BC1051L carrier tape [23] 24 
Table 11 Surface resistivity values of the carrier tapes and cover tapes of the tape and 
reel carrier used in this thesis ...................................................................................... 26 
Table 12 Tensile strength values of the carrier tape and cover tape of the tape and reel 
carriers used in this thesis ........................................................................................... 28 
Table 13 Peel strength of the cover tapes used in this thesis ...................................... 28 
Table 14 Adsorption capacity values of the desiccant at 60 ?C / 60% RH and 40 ?C / 
60% RH ....................................................................................................................... 31 
Table 15 Long-term storage degradation mechanisms for moisture barrier bags ...... 36 
Table 16 Long-term storage degradation mechanisms for tape and reel carrier ......... 42 
Table 17 Details of tensile testing machine used for measuring the seal strength of MBB 
samples ........................................................................................................................ 48 
Table 18 Technical specifications of the wireless TH sensor used in this experiment50 
Table 19 Adsorption capacity of the desiccants at different temperature/RH conditions
..................................................................................................................................... 55 
Table 20 Combinations of temperature/relative humidity obtained from design of 
experiments software - JMP Pro ................................................................................. 58 
Table 21 Combinations of test conditions that were chosen to run on MBBs and 
desiccants .................................................................................................................... 58 
Table 22 Aging conditions and aging time for measuring the change in surface 
resistivity ..................................................................................................................... 72 
Table 23 Surface resistivity values obtained for the inner and outer layer of the MBB 
from Pro-4 four-point resistivity system before aging ................................................ 72 
Table 24 Surface resistivity values obtained for the carrier tapes used in this thesis from 
the Pro-4 four-point resistivity system before aging ................................................... 75 
Table 25 Dimensional requirements for carrier tape set by EIA standard 481-E ....... 80 
Table 26 Aging conditions and aging time for the experiments conducted for polymeric 
shrinkage mechanism .................................................................................................. 80 
Table 27 Summary of results ...................................................................................... 94 
Table 28 Color indication by HIC at different RH environment .............................. 109 
Table 29 Thickness of each layer of the MBB and the whole MBB in microns ...... 111 
  
v 
 
 
List of Figures 
Figure 1 Long-term storage system and its elements .................................................... 4 
Figure 2 Long-term storage system environment ......................................................... 5 
Figure 3 Construction of the SCS Dri-Shield 3700 series MBB as provided by the 
manufacturer ............................................................................................................... 15 
Figure 4 Concentration terms in the Fick's first law of diffusion equation ................ 18 
Figure 5 Two types of tape and reel along with its sub-elements ............................... 22 
Figure 6 Tray carriers with pockets and loaded with Plastic Quad Flat Packages (PQFP) 
components ................................................................................................................. 22 
Figure 7 Graph showing the mass of water vapor adsorbed by desiccant vs. time at 60 
?C / 60% RH and 40 ?C / 60% RH ............................................................................. 31 
Figure 8 Reproduced adsorption isotherm graph of bentonite clay at 25 ?C and 40 ?C 
from literature [27] ...................................................................................................... 33 
Figure 9 Change in average peel strength of 3M heat-activated cover tapes at room 
temperature, 400C and 600C for 60 days ..................................................................... 41 
Figure 10 Recommended dimensions by ASTM F88 standard for the samples to 
measure the seal strength [31] ..................................................................................... 45 
Figure 11 Representation of the sealed cut strip that is clamped onto the grips of the 
tensile testing machine [31] ........................................................................................ 45 
Figure 12 Sample I and sample II prepared for measuring the seal strength using the 
tensile testing machine ................................................................................................ 47 
Figure 13 Picture showing the MBB with the seal made by its manufacturer ........... 47 
Figure 14 Picture showing the MBB samples that are being clamped onto the grips of 
the tensile testing machine .......................................................................................... 48 
Figure 15 Graph showing the load vs. displacement results obtained for sample I and 
sample II...................................................................................................................... 49 
Figure 16 Flowchart describing the test procedure to determine the moisture adsorbing 
effectiveness of the desiccants above 50 ?C ............................................................... 52 
Figure 17 Representation of desiccants placed inside the temperature/relative humidity 
chamber ....................................................................................................................... 53 
Figure 18 Graph showing the amount of water adsorbed per unit gram of desiccant vs 
the number of hours the desiccants were placed inside the TH chamber ................... 55 
Figure 19 Flowchart showing the test procedure for accelerated experiments on MBBs
..................................................................................................................................... 59 
Figure 20 Image of MBB cut into a sealed area of 7.25 ? 8 in2, a wireless 
temperature/relative humidity sensor and 33g of desiccant before vacuum sealing .. 60 
Figure 21 Image of vacuum sealed MBBs containing wireless temperature/relative 
humidity sensor and 33g of desiccant inside it ........................................................... 60 
Figure 22 Image showing the vacuum sealed MBBs hanging inside the 
temperature/relative humidity chamber ...................................................................... 61 
Figure 23 Graph showing the temperature and relative humidity inside MBB measured 
by wireless sensor vs time for MBB sealed without desiccant at 60?C/85%RH as 
external condition........................................................................................................ 63 
vi 
 
 
Figure 24 Graph showing the temperature and relative humidity inside MBB measured 
by wireless sensor vs time for MBB sealed with 1/2 unit of desiccant at 60?C/85%RH 
as external condition ................................................................................................... 64 
Figure 25 Graph showing the temperature and relative humidity inside MBB measured 
by wireless sensor vs time for MBB sealed with 33g of desiccant at 60 ?C / 85% RH as 
external condition........................................................................................................ 64 
Figure 26 Graph showing the comparison of relative humidity inside MBB between 
MBBs sealed without desiccant, with 16.5gof desiccant and 33g of desiccant at 60 ?C 
/ 85% RH as external condition .................................................................................. 65 
Figure 27 Graph showing the temperature and relative humidity inside MBB measured 
by wireless sensor vs time for MBB sealed without desiccant at 40 ?C / 93% RH as 
external condition........................................................................................................ 66 
Figure 28 Graph showing the relative humidity inside MBB vs time as comparison 
between MBBs sealed without desiccant when placed at 60 ?C / 85% RH and 40 ?C / 
93% RH ....................................................................................................................... 67 
Figure 29 Graph showing the increase in relative humidity inside MBB when placed at 
60 ?C / 85% RH and 40 ?C / 93% RH after shifting and RH and time scale of Figure 
28 to zero..................................................................................................................... 67 
Figure 30 Graph showing the temperature and relative humidity inside MBB measured 
by wireless sensor vs time for MBB sealed with 16.5g of desiccant at 40 ?C / 93%RH 
as external condition ................................................................................................... 68 
Figure 31 Graph showing the temperature and relative humidity inside MBB measured 
by wireless sensor vs time for MBB sealed with 33g of desiccant at 40 ?C / 93% RH as 
external condition........................................................................................................ 68 
Figure 32 Graph showing the comparison of relative humidity inside MBB between 
MBBs sealed without desiccant, with 16.5g of desiccant and 33g of desiccant at 40 ?C 
/ 93% RH as external condition .................................................................................. 69 
Figure 33 Picture showing the different set of carrier tape samples used for accelerated 
aging experiments ....................................................................................................... 70 
Figure 34 Image showing the Signatone Pro-4 Four-Point Resistivity System.......... 71 
Figure 35 Graph showing the change in surface resistivity of the outer layer of the MBB 
vs. aging time for different runs .................................................................................. 74 
Figure 36  Graph showing the change in surface resistivity of the inner layer of the 
MBB vs. aging time for different runs ........................................................................ 74 
Figure 37 Graph showing the change in surface resistivity of the C167CR carrier tape 
vs. aging time for different runs .................................................................................. 77 
Figure 38 Graph showing the change in surface resistivity of ST10F276x carrier tape 
vs. aging time for different runs .................................................................................. 78 
Figure 39 Graph showing the change in surface resistivity of XC2288H carrier tape vs. 
aging time for different runs ....................................................................................... 78 
Figure 40 Picture showing the dimensions (D0  and P0) of the carrier tape as provided 
by EIA 481-E [37] ...................................................................................................... 80 
Figure 41 Optical microscopic image showing the measurement of pitch and diameter 
of sprocket holes ......................................................................................................... 81 
vii 
 
 
Figure 42 Graph showing the change in percentage of the diameter of the sprocket holes 
vs. aging time for different carrier tape samples at running 1 condition .................... 83 
Figure 43 Graph showing the change in percentage of the pitch of the sprocket holes 
vs. aging time for different carrier tape samples at run 1 condition ........................... 84 
Figure 44 Graph showing the change in percentage of the diameter of the sprocket holes 
vs. aging time for different carrier tape samples at run 2 condition ........................... 84 
Figure 45 Graph showing the change in percentage of the pitch of the sprocket holes 
vs. aging time for different carrier tape samples at run 2 conditions .......................... 85 
Figure 46 Graph showing the relative humidity inside MBB vs. Time recorded by 
wireless sensor inside MBB sealed with 16.5g of desiccant at 40 ?C / 93% RH 
(Modified version of Figure 43) ................................................................................. 88 
Figure 47 Graph showing two subplots - Top subplot shows the relative humidity inside 
MBB vs. time and the bottom subplot shows the corresponding mass of water vapor 
adsorbed by desiccant vs. time .................................................................................... 90 
Figure 48 Graph showing two subplots with estimates of time to reach 5% RH and 10% 
RH inside MBB, and corresponding mass of water vapor adsorb by the desiccant ... 91 
Figure 49 Graph showing the comparison of theoretical results and results based on 
experimental analysis for ............................................................................................ 93 
Figure 50 Graph showing theoretical results for relative humidity inside MBB vs. time 
and mass of water vapor adsorbed by desiccant vs. time at 25 ?C / 60% RH as outside 
condition ..................................................................................................................... 94 
Figure 51 Tube carrier containing quad flat node (QFN) package components ....... 100 
Figure 52 Tray carriers with pockets and loaded with Plastic Quad Flat Package (PQFP) 
components ............................................................................................................... 102 
Figure 53 Trays stacked with the configuration of 10 loaded trays and one empty cover 
tray at the top ............................................................................................................ 102 
Figure 54 Two types of tape and reel along with its elements .................................. 104 
Figure 55 Dimensional requirement of camber in carrier tapes ............................... 104 
Figure 56 Carrier tape setup along the guideways of the pick and place machine for 
automatic component handling ................................................................................. 106 
Figure 57 Picture showing the adhered and back peeled cover tape ........................ 107 
Figure 58 HIC that complies with J-STD-033D ....................................................... 109 
Figure 59 Optical microscopic image showing the cross-section of the MBB......... 111 
Figure 60 Figure showing the EDS spectra obtained for the middle layer of the MBB
................................................................................................................................... 113 
Figure 61 Image showing the basic setup for measuring the surface resistance or 
resistivity ................................................................................................................... 115 
Figure 62 Picture showing the calibration of weighing scale used in the experiments
................................................................................................................................... 116 
Figure 63  Graph showing the temperature and relative humidity of the chamber when 
set at 600C/60%RH and 400C/60%RH ..................................................................... 117 
 
 
viii 
 
 
Chapter 1: Introduction 
The electronics industry is continually evolving with innovations in component 
design and architecture. The component manufacturers concentrate on the products 
with the largest and fastest return on investments. This bottom-line pressure leads to 
frequent trimming of product portfolios. The introduction of newer electronic 
components into the market favors the consumer electronics industries that 
manufacture short-life electronic products such as smartphones. However, it acts as a 
problem of component obsolescence for the end-product manufacturers, primarily in 
the defense, aerospace, and automotive sectors. The lifecycle of the end-products 
manufactured by these sectors, such as weapon systems, ships, telecommunications 
infrastructure, farm machinery, and medical equipment, is longer than the lifecycle of 
the electronic components that go into them. Simultaneously, it is the electronic system 
that often defines functional complexity for the products in those sectors. For example, 
the communication and decision support electronic systems are critical to the farming 
equipment's performance, thereby influencing the farmer?s farm output, plowing, and 
planting. The obsolescence of the components due to their discontinuation results in 
downtime when the farm machinery is serviced. This downtime can be very costly to 
the farmer/customer affecting their farm output.  
To mitigate the component obsolescence, certain measures such as negotiating with 
the component manufacturer, redesigning the end-product and associated 
manufacturing processes, buying from aftermarket sources, and performing a lifetime-
buy (LTB) or bridge-buy of near-obsolete or end-of-life component can be taken. In 
1 
 
 
most cases, lifetime-buy is the most commonly adopted measure by end-product 
manufacturers. This is because of the fact that undergoing redesign every time a 
product discontinuation notice is issued will be difficult for the end-product to get 
manufactured and serviced [1]. Lifetime-buy for an end-product manufacturer is 
defined as the process of buying sufficient quantity from the component manufacturers 
to meet the end-products? lifetime needs before the anticipated termination of 
component production [2].  
While lifetime-buy helps to support uninterrupted manufacturing operations 
following component obsolescence, it requires careful planning and a well-thought-out 
storage management system so as to maintain these components in as-received 
condition until the support for the end-product?s lifecycle is discontinued. For example, 
a company manufacturing the same model tractor for 10 years is expected by its 
customers to provide maintenance and repair support for more than 30 years. This 
requires the company to store the electronic components purchased as a part of lifetime-
buy in the warehouse for an extended period of time. During this long-term-storage 
(LTS) of electronic components, various environmental factors such as temperature, 
humidity, oxygen, dust particles, and other contaminants can cause the components to 
degrade. For example, prolonged exposure of electronic components in a high-humid 
environment during storage causes the moisture to permeate through the electronic 
components? epoxy molding compound (EMC). If uncontrolled, such exposure reduces 
the interfacial adhesion strength between the EMC and die, causing delamination and 
induces vapor pressure during solder reflow resulting in popcorn cracking [3].  
2 
 
 
Electronic manufacturing companies rely on standards, manufacturer?s handbooks, 
and literature that provide recommendations on storage conditions and suggestions on 
reliable practices to protect the components during long-term-storage from physical 
damage and degradation due to environmental factors. The most common practice 
suggested by these documents is to contain the components within carriers and pack 
them inside moisture barrier bags (MBBs) along with desiccant and humidity indicator 
card (HIC) during long-term storage. This is defined as long-term storage system in 
this thesis and is depicted in Figure 1. A long-term storage system consists of 
replaceable and non-replaceable elements. MBBs, carriers, HICs, and desiccants are 
labeled as replaceable elements as they can be replaced during the long-term storage 
until the electronic components are used for either manufacturing or repair processes 
after storage. The carriers such as tape and reel, tray and tubes protect the components 
from physical damage and electrostatic discharge damage to the components. Carriers 
are also used for manufacturing and assembly operations of components after storage. 
Tape and reel carriers are considered in this thesis. The desiccants are packed within 
the MBB to adsorb the moisture present within the MBB and adsorb the moisture that 
gets permeated through the MBB, and HICs indicate a fixed level of relative humidity 
(RH) inside the MBB. MBBs are vacuum sealed to protect the components from 
moisture-related degradation mechanisms and also protect the components from 
electrostatic discharge and electromagnetic interference. The detailed function of each 
of these replaceable elements of the long-term storage system is provided in 
Appendix A. 
3 
 
 
 
Figure 1 Long-term storage system and its elements  
The long-term storage system is placed in a controlled storage environment. 
Usually, there are two environments ? outside environment and inside environment. 
Outside environment is the temperature and relative humidity of air outside the MBB 
and Inside environment is the temperature and relative humidity of air inside the MBB. 
The long-term storage system environment considered in the thesis is shown in Figure 
2. Outside the MBB, temperature and relative humidity is maintained at 17 ?C ? 25 ?C 
and 30% RH ? 60% RH respectively. The chemical environment outside the system is 
air. The environment inside the system is vacuum and dry initially. However, this 
environment can change depending on the properties of MBB, desiccant and carrier, 
which has been discussed in Chapter 3: Materials and its Properties.  
Even though the electronic components and the carriers are packed within the 
MBB, the reliability of components can get compromised over time because the 
moisture from the outside environment permeates through the MBB and reaches the 
4 
 
 
inside where the permeated moisture gets adsorbed by the desiccant. The desiccant 
cannot adsorb the permeated moisture beyond its adsorption capacity, and as the 
desiccant is approaching to its adsorption capacity, relative humidity inside MBB 
increases over time, thus potentially affecting the reliability of stored components with 
respect to humidity related degradation mechanisms. Also, the surface resistivity 
property of the carriers and MBBs can degrade during long-term storage which could 
potentially affect the reliability of the stored components with respect to electrostatic 
discharge. As a result, the packaging media must be replaced in order to prevent the 
degradation of the components from affecting its manufacturability and reliability 
requirements. 
 
Figure 2 Long-term storage system environment 
This thesis discusses the methodology to determine the estimates of RH increase 
inside MBB versus time based on which engineering decisions can be made to obtain 
the replacement schedules for the desiccants and MBBs. It also reports on the 
experiments conducted to determine of the criticality of the surface resistivity 
degradation mode of the carriers and MBBs.   
5 
 
 
Chapter 2: Review of Standards and Prior Work on Long-Term 
Storage 
In this section, the literature review of the standards used for long-term storage of 
electronic components and a review on long-term storage study conducted by Texas 
Instruments is reported. Table 1 lists standards that are reviewed in this thesis. These 
standards provide the practices and recommendations for storing components for long-
term.  
Table 1 Long-Term Storage Standards for Electronic Components 
Standard Developed by Coverage Last Updated 
Name 
JEDEC JEP Joint Electron Recommendations on Sep 2016 
160 [4] Device Engineering best practices for 
Council (JEDEC) packing and storing 
Solid State the solid-state 
Technology electronics for long-
Association term storage 
GEIA-STD- SAE International Recommendations on Jan 2017 
0003A [5] long-term storage 
environment control 
guidelines 
IEC 62435 International Recommendations on Varies for each 
(Series of 9 Electrotechnical methods of long-term member of the 
standards) [6] Commission (IEC) storage  series 
 
JEDEC JEP 160 Standard 
The Joint Electron Device Engineering Council (JEDEC) standard JEP 160 defines 
the long-term storage as uninterrupted storage where the conditions and requirements 
of JEDEC J-STD-033 do not otherwise apply. The long-term storage requirements and 
conditions stated in JEP 160 are applicable when stored for more than one year as 
opposed to J-STD-033, which provides the requirements for storage less than one year.  
6 
 
 
To prevent the electronic components from environmental damage and to maintain 
the reliability of the components during long-term storage, the JEP 160 standard 
recommends the following three methods ? dry cabinet storage, vacuum MBB storage, 
and nitrogen flush or positive-pressure MBB storage. In dry cabinet storage, the 
components are recommended to be stored inside a cabinet that is humidity and oxygen 
controlled. In vacuum MBB storage, the components are recommended to be packed 
within a vacuum MBB that contains HIC and oxygen sensor. MBBs are recommended 
to be flushed with dry nitrogen before vacuuming in this method. In positive-pressure 
MBB storage, MBBs are initially vacuumed, followed by filling with dry nitrogen or 
dry air at a positive pressure compared to the outside environment, to create an inert 
atmosphere inside the MBB. However, in this method, the MBBs are susceptible to get 
punctured because of the positive pressure inflation of the bag. Irrespective of the above 
methods, this standard also recommends packing an MBB within another MBB, which 
is named as double containment, if required.  
The standard also suggests performing certain verification tests on a regular 
schedule for both the packaging media and the components. Based on the results of the 
verification tests, the time to store further is recommended to be either increased or 
decreased. Verification tests for the packaging media include monitoring the HIC for 
any change in color, verifying the integrity of the MBB seal, and monitoring the oxygen 
sensor for any increase in the amount of oxygen inside the storage container or MBB. 
For the components, the verification tests are recommended to be performed by 
introducing ?surrogate hardware? along with the other components. The surrogate 
hardware is expected to act as a representative sample for the stored electronic 
7 
 
 
components that is suggested to be evaluated for any signs of damage or deterioration 
by undergoing pass/fail tests in a periodic schedule. For example, the surrogate 
hardware can undergo cross-sectioning of the leads periodically to measure and 
compare the length of the grown intermetallic layer against the pass/fail criteria. 
Decisions involving choosing the environmental conditions for long-term storage are 
recommended to be evaluated by the users themselves based on the types of 
components and the packaging media used for storage. 
Although this standard provides the methods of storing the electronic components 
for long-term, the standard did not report on how long one can use these packaging 
methods to store the components. While the standards provide recommendations for 
periodic evaluation of surrogate electronic components, it did provide any information 
on periodic evaluation of packaging media and also it did not report on how long one 
can use the packaging media before which they should be replaced during long-term 
storage.   
GEIA-STD-0003A Standard 
The standard GEIA-STD-0003A developed by SAE International recommends 
long-term storage practices for electronic devices by providing guidelines to packaging 
based on the required protection level. The standard defines the long-term storage as 
?any device storage for more than 12 months but typically allows for much longer 
(years)?.  
8 
 
 
The standard recommends the storage environment to be maintained at a 
temperature of 17 ?C ? 25 ?C and relative humidity of 7% - 25%. Similar to JEDEC 
JEP160, components are required to be stored within the sealed MBB that is either 
vacuumed or filled with dry nitrogen. In addition to packing those components inside 
either vacuum MBB or dry nitrogen MBB, it also recommends storing the sealed MBBs 
containing components inside the rigid containers that provides temperature-controlled 
protection, ionizing and non-ionizing radiation protection, extraneous chemical 
contamination protection, and mechanical protection (e.g., shock, vibration, 
movement). Based on the nature of the electronic components stored, protection levels 
are defined with the packaging requirement, as shown in Table 2. Along with all other 
aspects of how the protection should be provided, the standard covers the general 
aspects of the long-term storage control that starts right from the initial inspection to 
the removal or partial removal from storage. 
Similar to JEDEC JEP 160, this standard also did not report on the time to store the 
components and their packaging media without affecting the manufacturability and 
reliability requirements of electronic components. Also, this standard explicitly 
mentions that the packing requirements provided in the standard help to mitigate only 
?some? of the degradation mechanisms while there are many known and unknown 
factors that cause other degradation mechanisms to the packaging media especially. 
However, identifying the critical degradation mechanisms for both the components and 
packaging media will be crucial in estimating the replacement schedules based on those 
critical degradation mechanisms.  
9 
 
 
Table 2 Packing requirement for the protection level mentioned in SAE GEIA-STD-0003A standard 
Protection Are Are Are Packaging 
Level components components components requirement 
highly valued sensitive to moisture-
and/or outgassing? sensitive? 
irreplaceable? 
Level 1 No No No Components 
placed in a sealed 
MBB along with 
desiccant. MBB is 
then placed in a 
protective 
container 
Level 2 No No Yes Components 
placed in a sealed 
MBB filled with 
dry N2. MBB is 
then placed in a 
protective 
container 
Level 3 No Yes Yes Components 
placed in a sealed 
MBB filled with 
both dry N2 and 
desiccant. MBB is 
then placed in a 
protective 
container 
Level 4 Yes --- --- Components 
placed in a sealed 
MBB filled with 
both dry N2 
and/or desiccant. 
MBB is then 
placed in a dry N2 
container that 
shall contain 
desiccant external 
to MBB. 
 
10 
 
 
IEC 62435 Standard 
In this standard, long-term storage is defined as the planned storage of components 
to extend the life cycle for a duration with the intention of supporting future use. The 
standard recommends undergoing long-term storage at a temperature maintained 
between 5 ?C and 40 ?C and relative humidity maintained between 20% and 50%. This 
standard also provides recommendation on periodic evaluation of surrogate hardware 
for electronic components with specific validation requirements before and after long-
term storage. However, no such recommendations were provided for packaging media.  
The three long-term storage standards considered in this thesis do not provide any 
recommendations for estimating the replacement schedules for packaging media, 
degradation mechanisms of the packaging media, risks involved in re-packing of the 
components, and risks involved in cyclic storage practices. This thesis addresses the 
limitations of long-term storage standards by identifying the criticality of certain 
degradation mechanisms for packaging media and developing a methodology to 
estimate the replacement schedules of MBBs and desiccants based on its properties.  
Long-Term Storage Study by Texas Instruments 
Texas Instruments performed a study on packaging media along with the 
components to obtain its shelf life by storing them together at <40 ?C and <90% RH 
for periods of time ranging from 2 to 17 years [7]. Along with the evaluation of long-
term stored components, carriers such as tubes and tape and reel used as packaging 
media for those components were also evaluated for any degradation in static 
11 
 
 
dissipative properties during their long-term storage study. The cover tape of tape and 
reel carriers were evaluated for any degradation or change in the peel strength when 
they were stored for long-term. MBBs were evaluated for any moisture leak into the 
inside environment and any fading of marking and labels printed on MBBs.  
From the results of the evaluations made on packaging media, it was concluded that 
the moisture diffusion through MBB limits the life of packaging media. A standard 
MBB can be used for 32 months and MBBs intended for long-term storage can be used 
for more than 5 years. Although their study reported on the operating life of MBB, it 
may vary for different properties of MBBs and the permeation property for standard 
MBB and long-term stored MBB was not reported. As a result, it is difficult to correlate 
the life of MBB with its properties based on their study. Also, their study did not report 
on how long one should use and replace the desiccant sealed inside MBB before 
reaching its adsorption capacity. This thesis provides a methodology to estimate the 
replacement schedules based on the properties of MBBs and desiccants before 
undergoing long-term storage.  
  
12 
 
 
Chapter 3: Materials and its Properties 
Moisture barrier bags, desiccants, and tape and reel carriers are the packaging 
materials evaluated in this thesis. This section details the manufacturer information, 
construction, and important properties of those materials. Some of the important 
properties, which will be used for the evaluation of experimental results performed on 
them, are not provided by the manufacturers. Those properties are determined by either 
conducting experiments or using the available information provided by the 
manufacturer, which is also included in this section.  
Moisture Barrier Bags 
Moisture barrier bags (MBBs) are used for dry packing of electronic components. 
They act as a barrier for moisture permeation from the outside to the inside environment 
of the long-term storage system. They are also provided with antistatic and static 
dissipative coatings that shields the components from the electrostatic discharge (ESD), 
thus, protecting the components from moisture and ESD related degradation 
mechanisms. 
Manufacturer Provided Information 
Dri-Shield 3700 series MBBs manufactured by SCS are used in this thesis. The 
SCS manufacturer claims that their MBBs provide superior protection for ESD 
sensitive and moisture sensitive electronic components [8]. The SCS manufacturer 
provides 1 year of warranty from the date of purchase and also claims that the shelf life 
13 
 
 
of these bags is 5 years from the date of purchase when stored in a climate-controlled 
environment with ventilation [9]. Though the shelf life of the MBBs is not the same as 
that of the use-life, degradation mechanisms that occur during its shelf-life can be 
extended to its use-life. For example, manufacturers claim that the aluminum foil layer 
of the MBB could oxidize if exposed to environmental factors such as ultraviolet 
sunlight, moisture, or heat during storage [8]. While these environmental factors can 
cause oxidation of the aluminum foil layer during shelf life, they can also cause the 
same degradation mechanisms during their use-life as well. 
Construction of MBB 
Dri-Shield 3700 series MBB is made of layers of polymers and aluminum foil along 
with a static dissipative coating. Figure 3 shows the construction of this MBB as 
provided by the manufacturer. From the construction provided by the manufacturer, it 
can be figured out that the outer layer is made of static dissipative polyester, and the 
inner layer is made of static dissipative polyethylene. Also, an aluminum foil is 
laminated in between these two polymeric layers. This construction is usually named 
as a metalized film with aluminum foil acting as a barrier layer to moisture, and 
polymers are laminated to aluminum foil for better heat sealing and improved crease 
resistance of the aluminum foil [10]. The aluminum foil also acts as a Faraday cage to 
shield the electronic components sealed within it from any electromagnetic interference 
from the outside. The static dissipative coating offers protection to the components 
from electrostatic discharges because of its conductive native by carrying away the 
developed static charges from a localized spot and redistributing it along the surface. 
14 
 
 
Table 3 lists the properties of the MBB and its corresponding values as provided by the 
manufacturer along with the standard that is used to test that corresponding property 
[11]. Cross-section analysis, Fourier Transform Infra-Red (FTIR) spectroscopic 
analysis, Energy-Dispersive X-Ray Spectroscopic (EDS) analysis and surface 
resistivity analysis performed on the MBB is discussed in Appendix B.  
 
Figure 3 Construction of the SCS Dri-Shield 3700 series MBB as provided by the manufacturer 
Table 3 Properties of the MBB as provided by the manufacturer [11] 
Property Value Testing Standard 
Thickness 106.7 ?10% ?m MIL-STD-3010 Method 
1003 
Moisture vapor ? 4.7 mg/m2/day (at 38 ASTM F1249 and MIL-
transmission rate ?C / 90% RH) STD-3010C (Method 
(MVTR) 3030) 
Surface resistance (Both 1 x 104 to < 1 x 1011 ANSI/ESD STM 11.11 
inner and outer layer) Ohms 
Puncture resistance 111 N MIL-STD 3010C 
Method 2065 
Seal strength 66 N ASTM D882 
Tensile strength 68 MPa ASTM D882 
 
15 
 
 
Moisture Permeation Property of MBB - Permeability 
Moisture vapor transmission rate, abbreviated as MVTR, and permeability are the 
two properties associated with the moisture permeation mechanism of the MBB. 
MVTR is the time rate of water vapor flow normal to the surfaces, under steady-state 
conditions, per unit area [12]. The unit of MVTR is g/m2/day, which represents the 
amount of the water vapor that permeates through the area of 1 m2 in a day. The MVTR 
property of MBB varies with temperature, outside and inside relative humidity. The 
relationship between MVTR, temperature, and relative humidity is obtained by using 
the Fick?s first law of diffusion [13]. The equation for Fick?s first law is shown in 
equation ((1), where F represents the flux which is defined as the mass of water vapor 
permeated through unit cross-section area of the MBB per unit time. The flux term used 
in the Fick?s law is commercially named as MVTR in the units of g/m2/day. D is 
diffusion constant of the MBB in m2/s. ???? is concentration gradient, as shown in Figure 
????
4, represents the difference between the concentration of water vapor at the inner 
surface of the MBB, ?? ????1  ( 3), and the outer surface of the MBB, ????1  (
??
3), divided by ?? ??
the thickness of the MBB, L (m).  K in equation (2) represents the partition coefficient 
or equilibrium constant that establishes the equilibrium between the concentration of 
water vapor at the surface and the concentration of water vapor of the surrounding air 
to which the surface is exposed. K is defined as the ratio of concentration of water 
vapor at the inner surface of the MBB, ?? ????1  ( 3), to the concentration of water vapor in ??
the air inside the MBB, ?? ? ???? 3?.  Similarly, K can be defined for the outer surface of ??
16 
 
 
2
the MBB. Substituting (2) in (1), and replacing flux, F as MVTR, permeability, P (?? ),  
??
, of MBB is obtained in the equation (3), which is defined as the product of diffusion 
constant of MBB and partition coefficient of MBB. Permeability can also be defined 
as the mass of water vapor permeated through unit cross sectional area of MBB per unit 
time per unit difference between the concentration of the water vapor in air between 
the inside and outside of MBB multiplied by the thickness of MBB. The equations (1) 
to (3)shows the difference in concentration of water vapor as the driving force for the 
moisture to permeate from the outside to the inside of MBB, which can also be replaced 
by relative humidity (RH) as MVTR is directly proportionally to ?????? as it is 
proportional to ???? as shown in equation (4). However, the units of permeability 
changes to ?? .  ??2  as the driving force changes from ???? to ?????? and equation (3) ??  .  ?????? .  ?????
becomes equation (5), where ?????????? represents the relative humidity outside the MBB 
and ???????? represents the relative humidity inside the MBB. Permeability depends on 
temperature as shown in the equation (6) [14] [15] [16], where a and b are coefficient 
of permeation constant ( ?? .  ??2 )   and exponential factor (K) respectively. ??  .  ?????? .  ?????
Substituting equation  (6) in (5), we obtain the relationship between MVTR, 
temperature and relative humidity as shown in equation (7). 
???? ??  ?  ?? (1) 
?? = ??? = ??? ??1 ??1 
???? ??
?? ?? (2) 
?? =  ??1 = ??1 
???? ????
????  ?  ???? = ???????? = ? (?? ? ??) ??
??
= ?? ?  ??
 ?  ???? (3)  
?? ??
17 
 
 
???????? ?? ???? ?? ??????  (4) 
?? (5) 
???????? =  (?????????? ?  ????????)  ??
?? = ?? ? ???????? (6) 
?? ? ???????? (7) 
???????? =  (?????????? ?  ????????) ??
 
Figure 4 Concentration terms in the Fick's first law of diffusion equation 
To obtain the permeability of MBB, the constants a and b in equation  (7) need to 
be determined. If the MVTR values of the MBB at two temperature/RH conditions are 
known, then can be substituted in the equation (7) to obtain two equations and two 
unknowns which can be solved to obtain the values of constants - a and b. From the 
Table 3, it can be observed that the manufacturer of MBB provided the MVTR value 
at 38 ?C / 90% RH as the outside condition and 38 ?C / 0% RH as the inside condition. 
To obtain the values of MVTR at another condition, it is assumed that MVTR can be a 
linear function of difference in partial pressure of water vapor between the outside and 
inside of MBB, as shown in equation (8) [14] [4]. Here, ???????? represents the partial 
pressure of water vapor in air outside the MBB and ?????? represents the partial pressure 
of water vapor in air inside the MBB. If the inside condition is 0% RH, the partial 
pressure of water vapor in air inside the MBB is also zero. So, the MVTR is directly 
proportional to the partial pressure of water vapor in air outside the MBB. Substituting 
18 
 
 
the partial pressure inside the MBB to be zero, the MVTR values for the MBB are 
calculated for the two conditions - 60 ?C / 85% RH and 40 ?C / 93% RH at which the 
experiments are run for MBBs by linearly multiplying the outside partial pressure 
values of the corresponding condition. The calculated values of MVTR at different 
conditions are shown in Table 4. 
???????? ?? (???????? ?  ??????) (8) 
Table 4 Calculated values of MVTR at different temperature / RH conditions 
Outside temperature / Partial pressure of MVTR ( ???? ) 
RH condition water vapor at the ??  ??????
outside condition (atm), 
???????? 
38 ?C / 90% RH 0.0592 4.70E-3 
40 ?C / 93% RH 0.0678 5.38E-3 
60 ?C / 85% RH 0.1673 13.28E-3 
 
The values of MVTR at 38 ?C / 90% RH and 40 ?C / 93% RH as outside 
temperature / RH conditions are substituted in the equation (7) to obtain two equations 
and two unknowns, which are solved to obtained the values of a and b that are reported 
in Table 5. The value of b is represented as ???????, where ???? is activation energy in 
??  
??????
and R is universal gas constant in ??  . Substituting the value of R, activation energy 
?????? ??
is found to be 41.41 ????  or 0.4 eV. The obtained activation energy is observed to lie 
??????
within the ranges of moisture permeation mechanism. Also, the calculated constants a 
and b are substituted back in equation (7), to compare the MVTR values calculated 
from obtained a and b constants and the values from Table 4. The difference, as shown 
19 
 
 
in Table 6, is found to be 5 ?  10?4. Since these two MVTR values are comparable to 
two significant digits, the constant values a and b are validated and are substituted in 
the equation (6) at the required temperature to calculate the values of permeability at 
the corresponding temperature. Table 7 lists the calculated values of permeability 
property of MBB at 60 ?C and 40 ?C.  
Table 5 Calculated values of constants ? a and b in equation (6) 
Parameters Values 
a ( ?? .  ?? 5.39 
??2
)     
 .  ?????? .  ?????
b (K); b = ?????  4980.85 ??
 
Table 6 Comparison of MVTR values calculated based on linear assumption and calculated by 
substituting the obtained the constants - a and b in equation (7)  
 MVTR Value 
Value calculated based on linear 13.28E-3 
assumption as shown in Table 4 
Value calculated by substituting the 12.78E-3 
obtained constants a and b in equation  
((7) 
Difference 5E-4 
 
Table 7 Calculated permeability values at temperatures - 60 ?C and 40 ?C 
Temperature Permeability, P ( ?? .  ?? )     
???? .  ?????? .  ?????
60 ?C 17.21E-7 
40 ?C 6.62E-7 
 
Electrostatic Discharge (ESD) Protection Property ? Surface Resistivity 
Properties such as surface resistivity and electro-static discharge shielding are used 
as a measure to indicate the MBB?s protection from ESD damages to components 
20 
 
 
stored within them. Static dissipative materials are evenly dispersed or coated on the 
surface of the polymeric layers of MBB to improve the conductivity. As a result, the 
static charges that could get developed on the surface are carried away from a localized 
spot and are dissipated, thus protecting the components from any ESD damage. The 
conductivity of the polymeric layers is represented in terms of surface resistivity. The 
surface resistivity of the MBB is reported to be between 105 and 1012 ohms/sq by the 
manufacturer, which lies in the static dissipative region, according to ANSI/ESD S541 
[17]. Any change in the surface resistivity from the static dissipative region to the 
insulative region (? 1012 Ohms/Sq) can increase the risk of component damage due to 
ESD. 
Carriers  
Carriers are packaging media that are used to protect the components from physical 
damage and electrostatic discharge damage during transportation and storage. In 
addition to the function of protecting the components from physical and environmental 
damage, they are used as an aid in the manufacturing or assembly processes after 
storage. For example, carriers containing the integrated circuits such as 
microprocessors are fed along the rails of the pick and place machines that 
automatically pick those microprocessors from the carriers and place them in a specific 
orientation at a specific location on the circuit board for reflow soldering.  
Tape and reel carriers are considered in this thesis. Tape and reel carriers are usually 
of two types and consist of three sub-elements ? carrier tape, cover tape and reel as 
shown in Figure 5. In this thesis, experiments were conducted on embossed pocket type 
21 
 
 
tape and reel with a focus on carrier tape and cover tape sub-elements. Tray carriers are 
molded in rectangular shapes that nest the electronic components within a matrix of 
pockets that are uniformly spaced, as shown in Figure 6. Information related to tray 
carriers is provided in Appendix A. 
 
Figure 5 Two types of tape and reel along with its sub-elements 
 
 
Figure 6 Tray carriers with pockets and loaded with Plastic Quad Flat Packages (PQFP) components 
 
22 
 
 
Manufacturer Provided Information 
Table 8 lists three carriers used in this thesis along with their manufacturer name, 
series, and shelf-life information provided by the manufacturer. The carrier tapes are 
addressed based on the manufacturer part number of the component contained within 
it throughout this thesis. 
Table 8 Manufacturer information of the tape and reel carriers used in this thesis 
Manufacturer Shelf-life information 
part number of Carrier tape Cover tape provided by the the component 
contained manufacturer manufacturer 
manufacturer 
within the and series and series Carrier Cover Tape 
carrier Tape 
24 months 
5 years from the date 
from the of 
Advantek Advantek date of manufacture ST10F276 PS+C HUE manufacture when stored at Trilaminate  when stored 5 ?C ? 35 ?C 
at 21 oC ? and 15% RH 
17 ?C [18] ? 85%R H 
[19] 
24 months 
5 years from the date 
from the of 
Advantek Advantek date of manufacture XC2288H PS+C HUB manufacture when stored at Trilaminate  when stored 20 ?C ? 30 ?C 
at 21 ?C ? and 30% RH 
17 ?C [18] ? 80% RH 
[20] 
5 years 
from the 
date of 
C167CR Cpak-PS-BC1051L Unknown manufacture Unknown when stored 
at ? 45 ?C 
[21] 
23 
 
 
 
Material Composition Information  
The material composition information of the Advantek PS+C and Cpak-PS-
BC1051L carrier tapes as provided by the manufacturer is shown in Table 9 and Table 
10, respectively. The material composition information for the cover tapes is not 
available from the manufacturer. 
Table 9 Material composition information of Advantek PS+C carrier tape [22] 
Chemical Name Ingredients (CAS#) % 
(Weight) 
Acrylonitrile-butadiene-styrene (ABS) 9003-56-9  <65   
Polystyrene (PS)  9003-53-6  <20   
Carbon Black   1333-86-4  <10   
 
Additives (trade secret)   <5   
 
Table 10 Material composition information of Cpak-PS-BC1051L carrier tape [23] 
Chemical Name Ingredients (CAS#) % 
(Weight) 
Styrene copolymer 9003-53-6 90 - 95 
Carbon Black   1333-86-4  5 - 10   
 
Electrostatic Discharge Protection Property of Carriers ? Surface Resistivity 
Carrier?s protection to the components from ESD damage is defined in terms of 
surface resistivity property. For the ?carrier tape? of the tape and reel carriers used in 
this thesis, carbon black is dispersed in the polymeric matrix of the carrier tape. Carbon 
24 
 
 
black, being conductive in nature, increases the conductivity of the polymeric matrix. 
As a result, the static charges that could get developed on the surface are carried away 
from a localized spot and are dissipated.  
For the cover tape of the tape and reel carriers used in this thesis, both the top and 
bottom layer of the cover tape is reported to be coated with an antistatic layer by the 
manufacturer. This layer prevents the development of any static charges protecting the 
components from ESD damage while peeling the cover tape from the carrier tape. 
However, the surface resistivity of carrier tape of the tape and reel carrier is considered 
to be critical compared to the cover tape as the components are in direct contact with 
the carrier tape. Should any electrostatic discharge occur, carrier tapes should be able 
to dissipate the charges to protect the components, which are in direct contact with it, 
from any damage. The surface resistivity values of both the carrier tapes and cover 
tapes used in this thesis, as provided by the manufacturer, are reported in Table 11. 
According to the manufacturer, the surface resistivity values were obtained by 
following the standard ASTM D 257. 
25 
 
 
Table 11 Surface resistivity values of the carrier tapes and cover tapes of the tape and reel carrier used 
in this thesis 
Manufacturer Surface Resistivity 
part number of (Ohms/Sq) 
the component Carrier tape Cover tape 
contained manufacturer manufacturer 
within the and series and series 
Carrier 
Tape Cover Tape 
carrier 
Advantek 
ST10F276 PS+C Advantek ?105 to <1010 
Trilaminate  HUE 5
Advantek ?10  to 12
XC2288H PS+C Advantek <10  [18] 5 12
Trilaminate  HUB [21] 
?10  to <10  
C167CR Cpak-PS-BC1051L Unknown Unknown 
 
Mechanical Properties of the carriers 
This section provides the mechanical properties reported by the manufacturer for 
the tape and carrier used in this thesis. The mechanical properties that are included here 
are the tensile strength of the carrier and cover tape and peel strength of the cover tape 
of tape and reel carriers used in this thesis.   
Tensile Strength 
Along with the ESD protection to the components, carriers provide protection to 
any physical damage to the components that could occur during physical handling and 
transportation of the components. They are also used as an aid to the 
manufacturing/assembly process of the stored components after their long-term 
storage. The carriers get loaded onto the guided rails of the pick and place machines, 
where they get pulled by sprocket wheels that get engaged with the sprocket holes 
26 
 
 
provided on the edges of the carrier tapes of tape and reel carrier. Tensile strength is an 
important property for this specific operation of carrier tape of tape and reel carrier 
after storage. Any change to the strength can cause cracks in between the sprocket holes 
of the carrier tape, making misalignment or disengagement with the sprocket wheels, 
causing feeding error and trampoline (jumping off of the components from the carrier 
tape) of the components. This affects the manufacturability of the components after 
long-term storage. 
While the carrier tapes are getting pulled by the sprocket wheels, the cover tapes 
are peeled back from the carrier tape by pulling it in the opposite direction to the 
moving direction of the carrier tape. Any change in the tensile strength can cause the 
tearing of the cover tape. As a result, the cover tape does not get peeled from the carrier 
tape and is still adhered to the carrier tape. When this reaches the pick and place spot, 
it can result in manufacturability issues. The tensile strength of both the carrier tapes 
and the cover tapes used in this thesis, as reported by the manufacturer, is shown in 
Table 12. According to the manufacturer, the tensile strength values were obtained by 
following the standard ASTM D882. 
27 
 
 
Table 12 Tensile strength values of the carrier tape and cover tape of the tape and reel carriers used in 
this thesis 
Manufacturer Tensile Strength (MPa) 
part number of 
the component Carrier tape Cover tape 
contained manufacturer manufacturer Carrier Cover Tape 
within the and series and series Tape 
carrier 
Advantek 
ST10F276 PS+C Advantek HUE 69 [19] Trilaminate  
Advantek 45.5 [18] 
XC2288H PS+C Advantek HUB ? 48 [20] Trilaminate  
C167CR Cpak-PS-BC1051L Unknown 26 - 49 [21] Unknown 
 
Peel Strength of Cover Tapes of Tape and Reel carrier 
Peel strength represents the ability of the cover tape to get peeled from the initially 
adhered carrier tape for further manufacturing operations. Peel strength is defined as 
the average load per unit width of bond line required to separate progressively one 
member from the other over the adhered surfaces [24]. Any change in the peel strength 
cause inconsistent peeling resulting in the trampoline of the components. Table 13 lists 
the peel strength of the cover tapes used in this thesis, as reported by the manufacturer. 
The values were obtained by following the standard EIA 481. 
Table 13 Peel strength of the cover tapes used in this thesis 
Manufacturer part number Cover tape 
of the component contained manufacturer and Peel strength of the 
within the carrier series cover tape (grams) 
ST10F276 Advantek HUE 50 ? 25 [19] 
XC2288H Advantek HUB 50 ? 20 [20] 
C167CR Unknown Unknown 
28 
 
 
 
Desiccants 
Desiccant is an adsorbent material that adsorbs water vapor onto its surface from 
the environment to which the desiccant is expose. Typically, desiccant packets are 
packed inside the sealed MBBs to adsorb any moisture inside the bag, thus protecting 
the components from humidity related degradation mechanisms. The different types of 
materials used as desiccants are silica gel, clay, zeolite, activated alumina, molecular 
sieve, calcium oxide, anhydrous calcium chloride, and calcium sulfate. Based on the 
materials, desiccants adsorb water under different distinctive adsorption isotherms that 
are classified from type-I to type-VI, according to the International Union of Pure and 
Applied Chemistry (IUPAC) [25]. Using these adsorption isotherms, desiccant 
adsorption capacity is calculated based on the units of desiccant. According to MIL-D-
3464E, a unit of desiccant is defined as that quantity of desiccant, as received, which 
will adsorb 3g and 6g of water vapor at 25 ?C, 20% RH and 25 ?C, 40% RH 
respectively [26]. The adsorption capacity of the desiccant is a function of temperature 
and relative humidity, which differs for different materials. For example, at room 
temperature of about 25 ?C and relative humidity less than 35%, silica gel and clay 
desiccant have the similar moisture adsorption capacity whereas, at the same room 
temperature and relative humidity greater than 35%, silica gel has relatively higher 
moisture adsorption capacity than clay desiccant [27]. Therefore, the selection of 
desiccant material and adsorption capacity is based on the storage environmental 
conditions and adsorption isotherm of that material at those storage conditions.  
29 
 
 
Manufacturer Provided Information 
S-5165 Tyvek bag desiccants distributed by Uline is used in this thesis. The 
material of the desiccant is bentonite clay. 33g of this desiccant is equal to 33 grams of 
clay. The shelf life of the desiccant is 1.5 to 2 years if the pail is opened and 5 years for 
an unopened pail. The condition at which the desiccant is recommended to be stored is 
<30 ?C and <80% RH [28].  
Adsorption Capacity Property  
Adsorption capacity is defined as the mass of water vapor adsorbed by unit gram 
of desiccant in equilibrium with air at that temperature / RH condition [26]. 
Manufacturer of this desiccant reported that the desiccant adsorbs 20% of its weight 
when exposed to 25 ?C / 70% RH. This indicates that the desiccant?s adsorption 
capacity at 25 ?C / 70% RH is 0.2 g/g. Experiments were run on desiccants to determine 
its adsorption capacity at 60 ?C / 60% RH and 40 ?C / 60% RH. Three desiccants were 
taken at each test conditions and their mass were weighed before placing them at the 
conditions. The increase in mass of the desiccant was recorded at certain time intervals 
till it reached its saturation. The observed increase in mass of desiccant divided by the 
initial mass of desiccant is plotted against time as shown in the Figure 7. Adsorption 
capacity, in this graph, represents the stabilized values of the curves. Table 14 lists the 
adsorption capacity values of the desiccant at the run conditions which are calculated 
by taking average of the stabilized values of the three desiccants at each condition. It 
can be interpreted that the difference between the adsorption capacity of the desiccant 
at 60 ?C and 40 ?C is comparable to one significant digit. Also, the rate of adsorption 
30 
 
 
at 60 ?C is higher than at 40 ?C which can be interpreted that increasing the temperature 
can make the desiccant to reach its saturation faster.  
 
Figure 7 Graph showing the mass of water vapor adsorbed by desiccant vs. time at 60 ?C / 60% RH 
and 40 ?C / 60% RH 
 
Table 14 Adsorption capacity values of the desiccant at 60 ?C / 60% RH and 40 ?C / 60% RH 
Test Condition Adsorption Capacity (??) 
??
60 0C / 60% RH 0.2045 
(Average of A, B, and C Samples)  
40 0C / 60% RH  0.2121 
(Average of D, E, and F Samples)   
 
Adsorption Isotherm  
Adsorption isotherm establishes the relationship between the adsorption capacity 
of the desiccant (????2?? / ??????????) and relative humidity (RH) to which the desiccant is 
exposed at a constant temperature. From the literature [29], it is found that Freundlich 
31 
 
 
adsorption isotherm can be used for clay desiccant. The formula for the isotherm is 
shown in equation (9). ????2?? represents mass of water vapor adsorbed by desiccant in 
grams. ???????????????????? represents the mass of clay desiccant in grams.  
????2??  is the 
????????????????????
adsorption capacity of the desiccant in g/g. RH is the relative humidity to which the 
desiccant is exposed. ?? represents the Freundlich constant representing adsorption 
capacity. ?? represents Freundlich constant representing adsorption strength. The 
constants, ?? and ??, of this equation should be determined for obtaining the adsorption 
isotherm equation of the clay desiccant.   
????2?? = ?? ?  (????)1/?? (9) 
????????????????????
The literature [27] reported the adsorption isotherm graph for the clay desiccant at 
25 ?C and 40 ?C which has been reproduced in Figure 8. The values obtained from this 
graph are compared against the known values to decide if the graph represents the clay 
desiccant or not. The manufacturer reported that the bentonite clay desiccant adsorbs 
20% of its weight at 25 ?C / 70% RH, which means the adsorption capacity is 0.2 g/g 
at 25 ?C / 70% RH, whereas the Figure 8 shows 0.26 g/g. Similarly, comparing the 
desiccant?s adsorption capacity at 40 ?C / 60% RH, which is shown in Table 14, the 
Figure 8 shows that the desiccant adsorbs 0.25 g/g at 40 ?C / 60% RH. Although there 
are some variations, compared to other graphs obtained from the literature, the Figure 
8 showed comparable results with type of desiccant used in the thesis. Equations (10) 
and (11) represent the Freundlich adsorption isotherm equations with the numerical 
values substituted for constants which are obtained by curve fitting the values obtained 
32 
 
 
from this Figure 8 at 25 ?C and 40 ?C from 0% RH to 20% RH. The ??2 values obtained 
for the fit equation at 25 ?C and 40 ?C are 0.985 and 0.982 respectively. 
 
Figure 8 Reproduced adsorption isotherm graph of bentonite clay at 25 ?C and 40 ?C from literature 
[27] 
 
??
?????? 25 ???, ??2?? = 0.7193 ?  (????)1/1.113 (10) 
????????????????????
??
?????? 40 ???, ??2?? = 0.6913 ?  (????)1/1.201 (11) 
????????????????????
 
  
33 
 
 
Chapter 4: Degradation Mechanisms of Replaceable Elements  
This section describes the degradation mechanisms that can be critical for the 
replaceable elements of the long-term storage system. Degradation mechanisms of tape 
and reel carriers and moisture barrier bags, along with the failure mode and effects, are 
discussed and tabulated in this section. Degradation mechanisms of tray carriers and 
desiccants are not discussed in this thesis and will be investigated as a part of future 
study.  
Moisture Barrier Bags 
This section describes the degradation mechanisms of the moisture barrier bags that 
can occur during long-term storage along with the failure modes and effects that are 
observed after storage. The degradation mechanisms such as degradation of the adhered 
layer of the seal and degradation of the static dissipative layer are considered to be 
critical for MBBs based on the effects that are induced after long-term storage.  
Degradation of Adhered Layer of Heat Seal 
To protect the components from moisture-related degradation mechanisms, the 
MBBs are vacuum-sealed. The heat seal is formed as a result of fusion of the inner 
polyethylene layer at a specific temperature, pressure, and time. These thermally 
bonded seals were found to permit the transfer of water vapor through the polymeric 
packages, and it has been found that seals contribute to 24% of the total water vapor 
permeance through the polymeric packages.  This is possible due to the permeation of 
34 
 
 
water vapor through micro holes, weakened material, or some type of defect present in 
the seal that is defined by the seal strength [30]. Thus, seal strength is often defined as 
a measure of the total integrity of the package [31].  
The internal bonds of the adhered layer degrade over time, and as a result, the 
thermophysical properties of the seal change that results in change of seal strength [32]. 
This decrease in seal strength can cause the moisture vapor transmission rate (MVTR) 
to increase unexpectedly that, if unnoticed, may result in humidity-related degradation 
to the components and packaging media sealed within it. The failure modes and effects 
for the degradation of the adhered seal are tabulated in the first row of Table 15. The 
experimental analysis for this particular failure mechanism is not performed by 
measuring the seal strength of MBB at specific intervals after accelerated aging. On the 
other hand, the use-life of MBB is measured indirectly by performing aging tests under 
accelerated test conditions.  
Degradation of Static Dissipative Layer 
MBBs used in this thesis are coated with a static dissipative layer on the inner and 
outer layers to provide protection to the components from the electrostatic discharge 
damage. The static dissipative property of the polymeric carrier tape is obtained by 
adding organic additives, which decreases the surface resistivity from insulative region 
(>1012 Ohms/Sq) to static dissipative region (>105 to <=1012 Ohms/Sq). These additives 
are organic compounds that degrade over time, increasing the surface resistivity of the 
polymeric layers of MBBs [17] [33]. As a result, the MBBs may lose their protection 
to contained components from electro-static discharge damages. Also, in some cases, 
35 
 
 
the products that are outgassed as a result of degradation of the antistatic layer can 
become a source of contamination on the contained electronic components during long-
term storage. For example, an antistatic polyethylene bag contained n-octanoic acid 
that got vaporized and deposited on the leads of the components to form lead di (n-
octanoate) [34]. The failure modes and effects for the degradation of the static 
dissipative layer of MBB are tabulated in Table 15. The experimental analysis for the 
degradation of the static dissipative layer is provided in Chapter 5: Experiments and 
Results. 
Table 15 Long-term storage degradation mechanisms for moisture barrier bags 
Degradation Degradation Effects 
mode mechanism 
Change in Degradation of Unexpected increase in the moisture vapor 
the seal the adhered layer transmission rate (MVTR) of the MBB 
strength of of the heat seal 
the MBB 
Change in Vaporization of Risk of electronic components getting 
the surface the static damaged by ESD 
resistivity of dissipative layer The components may get contaminated with 
the MBB on the inner and the outgassed elements 
the outer 
polymeric layers 
of the MBB 
 
Carrier Tape of Tape and Reel 
The tape and reel carrier consist of elements such as carrier tape and cover tape. 
This section describes the degradation mechanisms of the carrier tape of tape and reel 
that can occur during long-term storage, along with the failure modes and effects that 
are observed after storage. For carrier tape of tape and reel, degradation mechanisms 
36 
 
 
such as polymeric shrinkage and degradation of the static dissipative layer are 
considered critical based on the effects that are induced after long-term storage.  
Polymeric Shrinkage   
Polymers can continue to shrink after processing, causing a slow contraction of 
their polymeric chains. As a result, the chains get closer decreasing the free volume 
within them, resulting in continued shrinkage over time [35]. When the carrier tapes 
made of polymers are stored for long-term, they can also undergo continued shrinkage 
causing a change in the dimensions. Also, shrinkage of polymers causes the polymeric 
chains to come closer, making the polymer stiffer and stronger. As a result, they 
become brittle and lose their ductile nature. 
Some manufacturers of carrier tapes have investigated the nature of this problem 
that can occur during long-term storage. 3M, a company that manufactures carrier 
tapes, has released a qualification report on dimensional changes associated with the 
polymeric shrinkage [36]. As a part of qualification testing, their polycarbonate carrier 
tapes were aged at 52 ?C and 85 ?C for 24 hours to determine the extent of dimensional 
change of their carrier tapes. According to EIA 481-E, the dimensions of the ten-pitch 
distance of the sprocket holes of the carrier tapes should be 40?0.2 mm (Tolerance is 
? 0.5%) [37]. The results of their aging tests showed that the dimensions of the carrier 
tapes showed a change in tolerance of less than 0.1% at both 520C and 850C, which 
were still within the range set by EIA 481-E. However, the carrier tapes used in this 
thesis are made of different material composition other than polycarbonate materials. 
37 
 
 
So, accelerated aging experiments are decided to be performed to determine if there is 
any noticeable change in the dimensions for the carrier tape that is used in this thesis.   
Change in dimensions, especially the diameter and pitch of the sprocket holes of 
the carrier tape, can cause misalignment or disengagement of the carrier tape with the 
sprocket holes. This can lead to rough feeding, mis-picks by the pick and place 
machine, trampoline of the components, and physical damage to the leads of the 
components, affecting the manufacturability of the components after long-term storage.  
Change in the ductility due to the continued shrinkage of polymers over time can 
cause the impact strength to decrease with the increase in the strength showing a ductile 
to brittle transition. As a result, the components contained within the carrier tapes may 
be subjected to impact damage after long-term storage when the carrier tapes are 
dropped accidentally while handling. Also, the ductile to brittle transition may cause 
cracks at the stress concentration sites of the sprocket holes while the carrier tapes are 
getting pulled, leading to feeding errors. The failure modes and effects for the 
polymeric shrinkage degradation mechanism of the carrier tape are tabulated in Table 
12. 
Degradation of Static Dissipative Layer  
The static dissipative property of the polymeric carrier tape is obtained by adding 
additives, which decreases the surface resistivity from the insulative region (>1012 
Ohms/Sq) to the static dissipative region (>105 to <=1012 Ohms/Sq). These additives 
are organic compounds that degrade over time, increasing the surface resistivity of the 
38 
 
 
polymer [17] [33]. As a result, the carrier tapes may lose their protection to contained 
components from electro-static discharge damages. Also, in some cases, the products 
that are outgassed as a result of degradation of the antistatic layer can become a source 
of contamination on the contained electronic components during long-term storage. 
The failure modes and effects for the degradation of the static dissipative layer are 
tabulated in Table 12. The experimental analysis for degradation of the static 
dissipative layer of MBB is provided in Chapter 4: Degradation Mechanisms of 
Replaceable Elements. 
Cover Tape of Tape and Reel ? Degradation of Adhesive Layer  
The cover tape is adhered to the top of the carrier tape to make the components 
contained within the pockets of the carrier tape. The cover tapes used in this thesis 
contain a heat-activated adhesive layer that helps in adhering to the carrier tape upon 
applying heat and pressure. The adhesive layer can degrade overtime during the long-
term storage causing a change in the peel strength. The factors that can cause a change 
in the peel strength over time are rearrangement of molecules due to the relaxation of 
residual stress, migration of chemical species between the polymer and the adhesive 
layer over time, and bulk movement of the polymeric chains in and around the bonded 
interface over time [24].  
3M has performed qualification tests on observing the change in the peel strength 
of their heat-activated cover tapes. They aged their cover tapes at room temperature, 
40 ?C, and 60 ?C for 60 days to determine the extent of change in the peel strength. The 
results that were published in their qualification reports are shown in Figure 9 [38]. It 
39 
 
 
is observed from the graphs that the peel strength of the cover tape increased initially 
and then stabilized at the end of 60 days for all three temperatures. Although the results 
did not show a significant change in the peel strength, this qualification report was 
specifically performed for their cover tapes. So accelerated aging experiments are 
decided to be performed for the cover tapes that are used in this thesis to determine the 
criticality of this degradation mechanism. The details of the experiment are provided 
in the section. 
When the cover tape is peeled from the carrier tape for the components to get picked 
up by the pick and place machines, the consistent peel strength is required. EIA 481-E 
standard defines the peel strength of the cover tape to be between 10.2g and 132.56g 
for 44mm width of carrier tape [37]. Any change in the peel strength beyond the limits 
specified by the standard affects the manufacturability of the components after long-
term storage.  The components pop out from the pockets of the carrier tape when there 
is a change in the peel strength and may result in components not getting picked up by 
the pick and place machines leading to feeding error. The failure modes and effects for 
the degradation of the adhesive layer are tabulated in Table 12. 
40 
 
 
 
Figure 9 Change in average peel strength of 3M heat-activated cover tapes at room temperature, 400C 
and 600C for 60 days 
 
41 
 
 
Table 16 Long-term storage degradation mechanisms for tape and reel carrier  
Elements Degradation Degradation Effects 
of tape and mode mechanism 
reel carrier 
Carrier tape  Change in Continued Rough feeding, Mis-picks by the 
dimensions dimensional pick and place machine, trampoline 
of the carrier shrinkage of of components, Physical damage to 
tape the polymers  the leads of the contained 
components 
Change in Polymeric Protection of components from 
the tensile shrinkage impact damages may be 
strength and causing compromised during handling after 
impact continued storage 
strength of transformation  
the carrier from the Decrease in the ductility can cause 
tape ductile to cracks in the gaps between the 
brittle nature sprocket holes leading to feeding 
of the error 
polymers 
Change in Degradation Risk of electronic components 
the surface of the static getting damaged by ESD 
resistivity of dissipative  
the carrier layer of the The components may get 
tape carrier tapes contaminated with the outgassed 
elements 
Cover tape  Change in Degradation Uneven peeling resulting in the 
the peel of the trampoline of components 
strength of adhesive layer 
the cover of the cover 
tape tape 
 
  
42 
 
 
Chapter 5: Experiments and Results  
This section describes the details of the experiments that were conducted on MBBs, 
desiccants and carriers. It includes the testing conditions, run time, number of samples, 
and measurements that were recorded for each of the conducted experiments. The 
results obtained from these experiments are also discussed in this section.  
Experiments for Determining RH Inside MBB vs. Time 
According to JEDEC J-STD-033D, when the relative humidity inside the MBB 
containing MSL 2A-5A electronic parts reaches 10% RH, the components should be 
baked [39]. However, the RH inside MBB sealed with desiccant increases from 0% RH 
to 10% RH as the desiccant is reached its adsorption capacity. As a result, it is critical 
to investigate how the RH inside MBB changes over time in order to make informed 
decisions about replacing MBBs and desiccants during long-term storage. In this 
experiment, MBBs are vacuum-sealed with wireless temperature/relative humidity 
sensor to monitor the change in RH inside MBB when placed at conditions ? 60 ?C / 
85% RH and 40 ?C / 93% RH. This section details the equipment used in this 
experiment, design of experiments and preliminary testing performed to determine the 
accelerated test conditions, experiment procedure, and the obtained results. 
Equipment Used in the Experiment - Vacuum Sealing Machine 
In this experiment, MBBs are vacuum sealed, necessitating the use of a vacuum 
sealing machine prior to performing experiments. The manufacturer's conditions for 
43 
 
 
sealing the MBB, as mentioned in [11], that includes sealing at a temperature of 204 
?C, a sealing pressure of 206 - 482 kPa, and a sealing time of 0.6 - 4.5 seconds. For 
economic reasons, a vacuum sealing machine that only controls the sealing time 
parameter is used to vacuum seal the MBB. The seal strength of the MBB sealed by 
this vacuum sealing machine is compared to the seal strength of the MBB sealed by the 
manufacturer. 
ASTM F88 standard is used for measuring the seal strength of the MBB samples 
[31]. As per the standard, the sealed MBB samples were cut into rectangular strips, as 
shown in Figure 10. The rectangular strip contains the seal portion and the portion for 
clamping the strip onto the tensile testing machine's grips. The seal lies in the middle 
of the two strips that are sealed together. The rectangular strip is then clamped onto the 
tensile testing machine's grips so that the distance between the grips is maintained 
between 10 and 25 mm, which is represented in Figure 11. The grips are pulled apart 
at a displacement ramp rate of 200 -300 mm/min. The result is recorded as a load vs. 
displacement graph from which the seal strength is measured.  
44 
 
 
 
Figure 10 Recommended dimensions by ASTM F88 standard for the samples to measure the seal 
strength [31] 
 
 
Figure 11 Representation of the sealed cut strip that is clamped onto the grips of the tensile testing 
machine [31] 
 
Two samples ? sample I and sample II were prepared according to the dimensions 
recommended by the ASTM F88 standard, which is shown in Figure 12. The samples 
were sealed using the vacuum sealing machine, and the sealing time was 8 seconds. 
Sample II was made by cutting the MBB with the seal portion that was sealed by the 
manufacturer. The seal marked in Figure 13 indicates the portion that was sealed by 
the MBB manufacturer. The tensile testing machine used in this experiment and its 
calibration details is reported in Table 17. The experiment was performed on November 
45 
 
 
9, 2020, and the testing conditions were reported to be 19.1 ?C / 20.3% RH. Figure 14 
shows the picture of the MBB samples clamped onto the grips of the tensile testing 
machine. The output for sample I and II is recorded and compared in the form of load 
vs. displacement graph, which is shown in Figure 15. The displacement in the x-axis 
of this graph represents the distance moved by the grips as they were pulled apart at a 
displacement ramp rate of 300 mm/min. The load in the y-axis of this graph represents 
the force resisted by the seal of the samples as they were pulled apart. The maximum 
seal strength was observed to be 158 N (35.52 lbs) for sample I and 183 N (41.14 lbs) 
for sample II. From the results, it can be observed that the difference between the 
maximum seal strength values of the manufacturer sealed MBB samples and the 
samples that were sealed using the vacuum sealing machine is 25 N (5.62 lbs). This 
difference is negligible when compared to magnitude of the absolute values of seal 
strength. The results of this comparison experiment justified the decision to seal the 
MBBs using this vacuum sealing machine before performing the accelerated 
experiments.  
46 
 
 
 
Figure 12 Sample I and sample II prepared for measuring the seal strength using the tensile testing 
machine 
 
 
Figure 13 Picture showing the MBB with the seal made by its manufacturer 
 
47 
 
 
Table 17 Details of tensile testing machine used for measuring the seal strength of MBB samples 
Asset Manufactu Descripti M/N S/N Last Calibrati
Number rer on Calibrati on Due 
on 
WC0517 Instron Tensile 598 B103 09/16/202 09/17/202
46 Tester 2 55 0 1 
WC0517 Instron Tensile 258 30022 09/16/202 09/17/202
48 Tester 0- 9 0 1 
Load Cell 301 
100kN 
 
 
Figure 14 Picture showing the MBB samples that are being clamped onto the grips of the tensile 
testing machine 
 
48 
 
 
Comparison of Maximum Seal Strength
200 182.92
158.03
150
100
Sample I - Manufacturer
50 sealed MBB
Sample II - MBB sealed using
vacuum sealing machine
0
0 2 4 6 8 10 12 14 16 18 20
Displacement (mm)
 
Figure 15 Graph showing the load vs. displacement results obtained for sample I and sample II 
 
Equipment Used in the Experiment - Wireless Temperature/RH Sensor 
To make an observation of the change in relative humidity inside the MBB after 
sealing, wireless temperature/relative humidity sensors and data loggers are used. This 
sensor is sealed inside the MBB and transmits the data wirelessly over WiFi. The data 
gets stored in the cloud and can be monitored. Table 18 lists the details of the wireless 
TH sensor used in this experiment. 
49 
 
 
Load (N)
Table 18 Technical specifications of the wireless TH sensor used in this experiment 
Manufacturer Elitech 
Model number RCW ? 360  
Temperature measurement range   -20 ?C to 70 ?C 
Temperature accuracy ?0.5 ?C 
Humidity measurement range 0% to 99% RH 
Humidity accuracy ?5% RH 
Humidity resolution 1% RH 
Battery  Rechargeable lithium battery 
Battery life before recharging Approximately 3 months at 1-hour 
recording interval 
 
Determination of Accelerated Test Conditions 
This section details the steps involved in choosing the test conditions for 
performing the accelerated experiments on MBBs. The test conditions are chosen based 
on the long-term storage system elements such as MBBs and desiccants and equipment 
such as wireless TH sensors used in this experiment. The chosen test conditions are 
then used as input for the design of experiment matrix to choose the combinations of 
appropriate test conditions for performing the experiments. 
In this accelerated experiment, desiccants are vacuum sealed inside the MBB and 
are put together inside the temperature/RH chamber. The accelerated test conditions 
should be chosen so that the desiccant?s functionality is not compromised. Literature 
shows that the clay desiccant loses its moisture adsorbing effectiveness above 50 ?C 
[27]. The manufacturer of the desiccant used in this experiment has also reported that 
its desiccant works best at temperatures below 48.9 ?C [40]. However, choosing all the 
accelerated test conditions below 50 ?C may not accelerate the moisture permeation 
mechanism into MBBs, making it more time-consuming to yield any conclusive 
50 
 
 
results. Therefore, desiccants were tested for their moisture adsorbing capability above 
50 ?C, and the following paragraphs discuss the details of the experiment performed 
on desiccants. 
Experiments on Desiccants to Determine the Accelerated Test Condition Above 
50 ?C 
This section describes the details of the experiment performed on desiccants to 
select accelerated test conditions above 50 ?C. Figure 16 shows the test plan that was 
followed to determine the moisture adsorbing performance of the desiccants above 50 
?C.  
In this experiment for desiccants, two temperatures were chosen. One of them was 
chosen to be above 50 ?C, and the other one was chosen to be below 50 ?C. The relative 
humidity was kept constant for both temperatures. The chosen test conditions were 40 
?C / 60% RH and 60 ?C / 60% RH. For each test condition, three desiccant samples 
were chosen to observe the variability in the measurements. Each desiccant sample is 
weighed using a weighing scale before placing them inside the temperature/relative 
humidity (TH) chamber at the chosen test conditions. Figure 17 shows the 
representation of how the desiccant samples are placed inside the TH chamber. The 
calibration of the weighing scale used for measuring the weight of the desiccant along 
with calibration of TH chamber used for this experiment is included in Appendix C ? 
Calibration Information of the Equipment. After placing three desiccants inside the TH 
chamber at each test condition, the desiccants were weighed at regular time intervals 
to record the increase in weight of the desiccant. This weight gain is caused by the 
51 
 
 
desiccant's adsorption of water vapor at the maintained relative humidity inside the 
chamber. This calculated gain in weight is divided by the weight of the desiccant 
measured before placing them inside the chamber to obtain the amount of water vapor 
adsorbed per gram of desiccant at each time interval. This process is repeated until the 
increase in weight of the desiccant values has stabilized.  
 
Figure 16 Flowchart describing the test procedure to determine the moisture adsorbing effectiveness of 
the desiccants above 50 ?C 
 
52 
 
 
 
Figure 17 Representation of desiccants placed inside the temperature/relative humidity chamber 
 
The graphs shown in Figure 18 depict the results of the experiment conducted for 
desiccants. On the y-axis of the graph, the amount of water vapor adsorbed by the 
desiccant per gram of desiccant is shown. The x-axis on the graph represents the 
number of hours the desiccants were inside the TH chamber. Desiccant samples A, B, 
and C were placed inside the chamber at 60 ?C / 60% RH, and the samples D, E, and F 
were placed at 40 ?C / 60% RH. The graph shows that the amount of water vapor 
adsorbed by the desiccant initially increased and then stabilized. This stabilized number 
is referred to as the desiccant's adsorption capacity, which represents the maximum 
quantity of water vapor that the desiccant can absorb at that temperature and relative 
humidity. Averaging the last three stabilized y-values of the same desiccant at both test 
conditions yields the adsorption capacity of each desiccant. Table 19 lists the 
adsorption capacity of each desiccant sample at the corresponding temperature and 
53 
 
 
relative humidity conditions. The adsorption capacities of the desiccant samples A, B, 
and C is observed to be comparable to those of the desiccant samples D, E, and F. This 
infers that the desiccant?s water adsorbing capability at 60 ?C (above 50 ?C) is same as 
that at 40 ?C (below 50 ?C). From this experiment, it is possible to conclude that 60 ?C 
can be used as one of the accelerated temperature conditions for accelerated 
experiments on MBBs.  
The adsorption rate of the desiccant at a specific temperature and relative humidity 
is defined as the time it takes to reach the adsorption capacity at the same temperature 
and relative humidity condition. From Figure 18, it can also be observed that the 
adsorption rate of the desiccant samples A, B, and C that were tested at 60 ?C / 60% 
RH is faster than the desiccant samples D, E, and F that were tested at 40 ?C / 60% RH. 
This suggests that temperature can act as an accelerator, shortening the time required 
to reach the adsorption capacity of the desiccant sealed inside the MBB. As a result, 
running the accelerated aging experiments of MBBs at 60 ?C is expected to shorten the 
total experiment time. 
54 
 
 
Desiccant Adsorption at 60 ?C / 60% RH and 40 ?C / 60% RH
0.25
0.2
0.15
A - 60C/60%RH
0.1 B - 60C/60%RH
C - 60C/60%RH
0.05 D - 40C/60%RH
E - 40C/60%RH
F - 40C/60%RH
0
0 20 40 60 80 100
Hours  
Figure 18 Graph showing the amount of water adsorbed per unit gram of desiccant vs the number of 
hours the desiccants were placed inside the TH chamber 
 
Table 19 Adsorption capacity of the desiccants at different temperature/RH conditions 
Desiccant Test Adsorption 
Sample Condition Capacity (????????/
????????????????????)  
A 060 C/60%RH 0.1966 
B 060 C/60%RH 0.1956 
C 060 C/60%RH 0.1943 
D 040 C/60%RH 0.2039 
E 040 C/60%RH 0.2013 
F 040 C/60%RH 0.2063 
 
55 
 
 
Amount of water vapor adsorbed per gram 
of desiccant (gH2O/gclay)
Test Conditions 
Since accelerating the temperature accelerates the desiccant's adsorption rate, one 
can infer that temperature can be one of the testing conditions for performing the 
accelerated experiments on MBBs sealed with desiccant. MVTR is a linear function of 
relative humidity between the outside and inside of the MBB. As the relative humidity 
outside the MBB increases, so does the MVTR, shortening the time it takes to reach 
the adsorption capacity of the desiccant, and thus 10 percent RH inside the MBB.  As 
a result, the two testing conditions that can be employed to accelerate the moisture 
permeation mechanism of MBBs are temperature and relative humidity. 
The test conditions, temperature and relative humidity, are chosen based on the 
conclusions of the experiments conducted for desiccants, the maximum operating 
temperature of wireless TH sensor, the glass transition temperature of MBB, and the 
actual storage environment. The experiments conducted for desiccants revealed that the 
desiccant could perform its water adsorbing function at 60 ?C. From Table 18, it can 
be observed that the maximum temperature that the Elitech wireless TH sensor can 
measure is 70 ?C. The glass transition temperature of the MBBs used in this thesis was 
found to be 105 ?C. The actual storage environment is 17 ?C ? 25 ?C / 30% RH ? 60% 
RH outside the MBB. Considering all of the aforementioned factors, 60 ?C is the 
maximum possible temperature that can be used, as temperatures above 60 ?C may 
affect the wireless TH sensor's measuring capability, resulting in inconclusive results. 
Therefore, three levels of temperature ? 40 ?C, 50 ?C, and 60 ?C and two levels of 
relative humidity ? 50% RH and 85% RH are chosen as the two conditions for this 
experiment. 
56 
 
 
Design of Experiments  
The chosen test conditions are utilized as input parameters in the design of 
experiments to establish the combinations of test conditions that can be employed for 
accelerated tests on MBBs. Using JMP Pro software, the maximum number of potential 
combinations for the three levels of temperature and two levels of relative humidity 
was determined to be 6 as shown in Table 20. As data on how long it takes to get to 
10% RH inside the considered MBB is not available, it is unknown whether performing 
experiments for all six combinations of test conditions will be time-consuming or not. 
Thus, it has been decided to start with two different test combinations initially as shown 
in Table 21 and observe the experiment duration based on which the decision to 
perform accelerated experiments on the remaining four combinations of test conditions 
will be made.  
It can be observed from Table 21 that 60 ?C / 85% RH is chosen as one of the test 
conditions which represents high/high pattern for both temperature and relative 
humidity. The other test condition was initially chosen to be 40 ?C / 85% RH that 
represents low/high pattern for temperature/relative humidity. However, due to reasons 
associated with availability of chamber, test condition 40 ?C / 93% RH was used with 
the assumption that the moisture permeation rate did not differ significantly between 
85% RH and 93% RH. 
57 
 
 
Table 20 Combinations of temperature/relative humidity obtained from design of experiments software 
- JMP Pro 
Temperature Relative Pattern (Temperature / Relative 
Humidity Humidity) 
40 85 Low / High 
50 50 Medium / Low 
60 50 High / Low 
40 50 Low / Low 
60 85 High / High 
50 85 Medium / High 
 
Table 21 Combinations of test conditions that were chosen to run on MBBs and desiccants 
Temperature Relative 
Humidity 
60 85 
40 93 
 
Experiment Procedure for Accelerated Aging of MBBs 
Figure 19 shows the procedure following for accelerated experiments on MBBs. 
The MBBs are vacuum sealed using the vacuum sealing machine with the desiccants 
and wireless TH sensor placed inside it. The sealed MBBs are placed inside the 
chamber at the test conditions as specified in Table 21. The chamber is run at the 
selected conditions with the RH inside the MBB is continuously monitored by the 
wireless RH sensor that was vacuum sealed inside the MBB. The time taken to reach 
the adsorption capacity of the desiccant sealed inside MBB is calculated based on the 
results obtained from these experiments.  
58 
 
 
 
Figure 19 Flowchart showing the test procedure for accelerated experiments on MBBs  
Sample Preparation 
MBBs are cut into rectangular shape with a sealed area of 7.25 ? 8 in2. Elitech 
wireless temperature/relative humidity sensors are placed inside the cut MBB before 
vacuum sealing. Three samples were prepared out of which one was sealed without 
desiccant, one was sealed with 16.5g of desiccant and the last one was sealed with 33g 
of desiccant. Figure 20 shows an image of MBB of area 7.25 ? 8 in2 sealed with 33g of 
desiccant. Figure 21 shows an image of vacuum sealed MBB. The vacuum sealed 
MBBs were punched with holes through which stainless steel hooks are inserted and 
hung onto the trays that were fit in the temperature/relative humidity chamber, as 
shown in Figure 22.  
59 
 
 
 
Figure 20 Image of MBB cut into a sealed area of 7.25 ? 8 in2, a wireless temperature/relative 
humidity sensor and 33g of desiccant before vacuum sealing 
 
 
Figure 21 Image of vacuum sealed MBBs containing wireless temperature/relative humidity sensor and 
33g of desiccant inside it 
 
60 
 
 
 
 
Figure 22 Image showing the vacuum sealed MBBs hanging inside the temperature/relative humidity 
chamber 
Results  
MBB samples were placed inside the chamber at two different conditions ? 60 ?C 
/ 85%RH and 40 ?C /9 3%RH. Figure 23, Figure 24 and Figure 25 shows the 
temperature and relative humidity recorded by the wireless sensor sealed inside MBB 
versus time for MBBs sealed without desiccant, with 16.5gof desiccant and with 33g 
of desiccant, respectively when placed inside TH chamber at 60 ?C / 85%RH. 
Similarly, Figure 27, Figure 30 and Figure 31 represents the temperature and relative 
humidity recorded by the wireless sensor sealed inside MBB versus time for MBBs 
sealed without desiccant, with 16.5gof desiccant and with 33g of desiccant, 
respectively when placed inside TH chamber at 40 ?C / 93%RH.  
It can be observed from Figure 23 that relative humidity increased from 16% RH 
to 37% RH at the end of 50 days of placing the vacuum sealed MBB inside TH chamber 
at 60 ?C / 85% RH. It is interpreted that sudden initial increase in inside RH from 16% 
61 
 
 
RH to 30% RH is due to the release of adsorbed water molecules from TH sensor as it 
is heated from laboratory atmospheric temperature (25?C) to TH chamber temperature 
(60?C) when placed inside TH chamber. Taking this into consideration, an increase of 
7% RH is observed inside the vacuum sealed MBB at the end of 50 days when placed 
at 60 ?C / 85% RH. Figure 23 can also be observed with abrupt increase and decrease 
in inside RH and temperature at around 2 days which is attributed to opening and 
closing of chamber at that time. When the chamber is opened, the temperature dropped 
from 60 ?C to 51 ?C that increased the RH inside MBB for the same moisture content 
contained within the MBB. When the chamber is closed, the temperature returns to 
60?C, and the RH inside MBB returns to the level it was before the chamber was 
opened. It should be noted that the resolution of the wireless sensor is 1% RH, which 
has been stated in Table 18. As a result, any line connecting the absolute values of RH 
within MBB is not parallel to the x-axis.  For example, the line connecting 34% RH 
and 35% RH is not parallel to the x-axis. It should be interpolated linearly to connect 
the two values that result in a line not parallel to the x-axis. 
62 
 
 
 
Figure 23 Graph showing the temperature and relative humidity inside MBB measured by wireless 
sensor vs time for MBB sealed without desiccant at 60?C/85%RH as external condition 
From Figure 24 and Figure 25, it can be observed that the relative humidity inside 
MBB is reduced to 2% RH at the end of 35 days and 55 days for MBBs sealed with 
16.5g and 33g of desiccant, respectively. The accuracy of the wireless TH sensor is 
?5% RH as stated in Table 18. This indicates that the RH inside MBB containing 
desiccant can be anywhere in between 0% RH and 5% RH. It can be observed from the 
graph that it took 7 days for the RH inside MBB to reach 2% RH for 16.5g of desiccant. 
On the other hand, for the MBB having a same sealing area, it took 2.5 days for the RH 
inside MBB to reach 1% RH for 33g of desiccant. This means that by sealing a 7.25 x 
8 in2 MBB with 33g of desiccant, the RH inside the MBB can be decreased to 1% RH 
in a shorter amount of time. Figure 26 shows comparison of relative humidity inside 
MBB vs time for MBBs sealed without desiccant and with 16.5gand 33g of desiccant.  
63 
 
 
 
Figure 24 Graph showing the temperature and relative humidity inside MBB measured by wireless 
sensor vs time for MBB sealed with 1/2 unit of desiccant at 60?C/85%RH as external condition 
 
 
Figure 25 Graph showing the temperature and relative humidity inside MBB measured by wireless 
sensor vs time for MBB sealed with 33g of desiccant at 60 ?C / 85% RH as external condition 
 
64 
 
 
 
Figure 26 Graph showing the comparison of relative humidity inside MBB between MBBs sealed 
without desiccant, with 16.5gof desiccant and 33g of desiccant at 60 ?C / 85% RH as external 
condition 
 
The MBB vacuum sealed with wireless TH sensors was placed inside the TH 
chamber at 40 ?C / 93% RH after 12 hours of performing vacuum sealing operation. 
This can be clearly observed from the temperature plot of Figure 27 that shows an 
increase in temperature from 25 ?C to 40 ?C at end of 0.5 days. At the time of placing 
the MBB inside the chamber, RH inside the chamber was 30% RH. It can be noticed 
that RH inside MBB increased from 30% RH to 38% RH at the end of 44 days when 
placed inside the TH chamber at 40 ?C / 93%RH. The explanation provided for the 
release of adsorbed water molecules from the wireless TH sensor when placed inside 
chamber at 60 ?C / 85%RH can be extended to 40 ?C / 93%RH condition for explaining 
a sudden increase in inside RH from 26% to 35%. So, the actual increase in inside RH 
is from 35% RH to 38% RH at the end of 44 days of placing the MBB sealed without 
desiccant at 40 ?C / 93%RH.  
65 
 
 
Figure 28 shows the comparison of inside RH vs time for MBBs sealed without 
desiccant between external conditions ? 60 ?C / 85%RH and 40 ?C / 93%RH. It might 
seem from Figure 28 that MBB placed at 40 ?C / 93%RH condition reached higher 
inside RH compared to MBB placed at 60 ?C / 85%RH at the end of 40 days. However, 
the RH inside MBB at the time of placing it inside chamber at 40 ?C / 93%RH is 26% 
RH, higher than the RH inside MBB at the time of placing at 60 ?C / 85%RH, which is 
16% RH. Therefore, to compare the increase in inside RH between the MBB samples 
placed at these two conditions, the y-axis (RH) and x-axis (time) is shifted to zero as 
shown in Figure 29. It can be inferred from Figure 29 that RH inside MBB placed at 
60 ?C / 85% RH increased by 20% RH whereas at 40 ?C / 93% RH it is increased only 
by 12% RH. This shows that temperature plays a role in increasing the permeation rate 
of water vapor from outside to inside of the MBB.  
80 40
70 35
60 30
50 25
40 20
30 15
20 10
Temperature
10 Relative Humidity 5
0 0
0 5 10 15 20 25 30 35 40 45 50
Time (Days)
 
Figure 27 Graph showing the temperature and relative humidity inside MBB measured by wireless 
sensor vs time for MBB sealed without desiccant at 40 ?C / 93% RH as external condition 
 
66 
 
 
Temperature Inside MBB ( 0C)
Relative Humidity Inside MBB (%)
 
Figure 28 Graph showing the relative humidity inside MBB vs time as comparison between MBBs 
sealed without desiccant when placed at 60 ?C / 85% RH and 40 ?C / 93% RH 
 
 
Figure 29 Graph showing the increase in relative humidity inside MBB when placed at 60 ?C / 85% 
RH and 40 ?C / 93% RH after shifting and RH and time scale of Figure 28 to zero  
 
From Figure 30 and Figure 31, it can be observed that the RH inside MBB is 
reduced to 4% and 1% at the end of 45 days for MBBs sealed with 16.5g and 33g of 
desiccant, respectively. Figure 32 shows the comparison of relative humidity inside 
67 
 
 
MBB vs time for MBBs sealed without desiccant and with 16.5g and 33g of desiccant 
at 40?C/93%RH.  
 
Figure 30 Graph showing the temperature and relative humidity inside MBB measured by wireless 
sensor vs time for MBB sealed with 16.5g of desiccant at 40 ?C / 93%RH as external condition 
 
 
Figure 31 Graph showing the temperature and relative humidity inside MBB measured by wireless 
sensor vs time for MBB sealed with 33g of desiccant at 40 ?C / 93% RH as external condition 
 
68 
 
 
 
Figure 32 Graph showing the comparison of relative humidity inside MBB between MBBs sealed 
without desiccant, with 16.5g of desiccant and 33g of desiccant at 40 ?C / 93% RH as external 
condition 
 
Accelerated Aging Experiment for Change in Surface Resistivity 
The failure mode of change in surface resistivity due to the degradation of organic 
compounds, which are added as additives to the polymeric layers, for improving the 
surface resistivity property is analyzed for its criticality in the following section.  
For measuring the surface resistivity of the MBB samples before and after aging, 
the samples were cut into rectangular shapes of dimension 8*4 cm2. Similarly, the three 
carrier tapes were cut into samples, as shown in Figure 33. These samples were then 
placed under the four-point probe of the Pro-4 system, which is shown in Figure 34. 
The four-point probe of the Signatone Pro-4 surface resistivity system was pressed 
against the surface of the samples to record the surface resistivity. The input parameter 
that is required for obtaining the surface resistivity from the Pro-4 system is the 
69 
 
 
thickness of the sample being measured. After having entered the thickness from Table 
29 (appendix), the lever of the Pro-4 system was pushed against the surface of the 
sample. The system auto-selects the current range and displays the resistivity for the 
selected current passed through the surface of the sample. 5 measurements of the 
surface resistivity were obtained by placing the four-point probe at 5 different locations 
on the surface for the same sample. The values were then averaged. The surface 
resistivity values of both the MBBs and carrier tapes samples were measured before 
and after accelerated aging, which is discussed in the below sections.  
 
Figure 33 Picture showing the different set of carrier tape samples used for accelerated aging 
experiments 
  
70 
 
 
 
Figure 34 Image showing the Signatone Pro-4 Four-Point Resistivity System 
To observe the change in surface resistivity in both MBB and carrier tape samples 
after aging, the samples were placed in a Temperature/Relative Humidity chamber at 
two different conditions ?? 850C/5%RH and 600C/25%RH. The aging conditions and 
the run time has been tabulated in Table 22. The surface resistivity values were 
measured at 5 different locations for each sample at each time interval for each run. 
The average of those 5 measurements was calculated and reported in the graph along 
with the maximum and minimum values. It is hypothesized that upon aging at higher 
temperatures, the organic compound additives degrade, resulting in an increase in 
surface resistivity. When the surface resistivity of the MBB and the carrier tape reaches 
the insulative region (> 1012 Ohms/Square), it is considered to be a failure criterion, at 
which point the aging experiments for measuring surface resistivity will be stopped.   
71 
 
 
Table 22 Aging conditions and aging time for measuring the change in surface resistivity 
 Run 1 Run 2 
Temperature/Relative 850C/5%RH  600C/25%RH 
Humidity Condition 
Run Time (Aging Period) 28 days 28 days 
Number of 5 5 
measurements at each 
time interval 
 
Moisture Barrier Bags 
Surface resistivity values of the MBBs were measured before aging by following 
the procedure are tabulated in Table 23. The surface resistivity values for both the inner 
and the outer layers of the MBB were found to be at 107 Ohms/square (? /sq), which 
matches with the specification provided by the manufacturer and lies within the static 
dissipative region. 
Table 23 Surface resistivity values obtained for the inner and outer layer of the MBB from Pro-4 four-
point resistivity system before aging 
Surface 
st nd rd th th
Resistivity 1  2  3  4  5  
Measurem Measurem Measurem Measurem Measurem Measurem
Avera
ent ent ent ent ent ge 
ent (? /sq) 
MBB outer 1.62 x 4.31 x 3.72 x 7 5.41 x 3.95 x 
layer 107 107 107 4.7 x 10  107 107 
MBB inner 8.72 x 4.39 x 4.18 x 2.87 x 3.73 x 4.78 x 
layer 107 107 107 107 107 107 
 
Figure 35 and Figure 36 show the graph of the change in surface resistivity 
observed for the outer and inner layer of the MBB after aging. The solid black lines at 
105 and 1012 Ohms/Sq in the graph show the lower and the upper limit for the static 
dissipative region. The blue and red line representing the run 1 and 2 respectively 
72 
 
 
passes through the mean of the 5 measurements that were taken at each time interval. 
The maximum and minimum values among the 5 measurements at each time interval 
is indicated as caps above and below the mean for both the runs. The whole range of 
surface resistivity values, including the maximum and minimum values, should be 
taken into account for any interpretation of the results.  
For run 1, the surface resistivity of the outer layer of the MBB stayed within the 
107 - 108 Ohms/Sq for the aging period of 28 days. The experiments for run 1 were 
stopped at the end of 28 days as the surface resistivity is observed to have reached a 
stable value and did not show any significant increase or decrease beyond 108 
Ohms/Sq. For run 2, the surface resistivity of the outer layer of the MBB showed a 
varying - increasing and decreasing trend and the maximum increase was observed to 
be 109 Ohms/Sq at the end of 4 and 28 days. Since the trend did not show any consistent 
increase or decrease in the surface resistivity values when aged for 28 days at run 2 
conditions, the experiments were stopped for run 2. Similarly, for both runs 1 and 2, 
the surface resistivity of the inner layers of the MBB showed an increase from 107 to 
108 Ohms/Sq initially, but then the value got stabilized by the end of 28 days. 
Although changes were observed in the mean values of surface resistivity for both 
the inner and outer layers of the MBBs, they were found to have the same range of 
values up to 28 days of aging. Also, the failure criteria of >1012 Ohms/Sq was never 
reached at the end of 28 days of aging. Therefore, the accelerated aging experiment for 
measuring the change in surface resistivity of the MBBs was stopped from running at 
the conditions set for runs 1 and 2.  
73 
 
 
 
Figure 35 Graph showing the change in surface resistivity of the outer layer of the MBB vs. aging time 
for different runs 
 
 
Figure 36  Graph showing the change in surface resistivity of the inner layer of the MBB vs. aging 
time for different runs 
 
74 
 
 
Carrier Tapes of Tape and Reel Carriers 
Carrier tapes are addressed by the manufacturer part numbers of the components 
contained within them. The surface resistivity values provided by the manufacturer are 
discussed in Table 11.The surface resistivity values of the carrier tapes - C167CR, 
ST10F276, and XC288H carrier tapes that were measured before aging is shown in 
Table 24. C167CR and XC2288H carrier tapes show an average of 108 and 105 (? /sq) 
respectively before aging, which is within the specification limits provided by its 
manufacturer. However, the surface resistivity value of ST10F276 carrier tape before 
aging was observed to be 104, which is below the lower limit specification provided by 
its manufacturer.  
Table 24 Surface resistivity values obtained for the carrier tapes used in this thesis from the Pro-4 four-
point resistivity system before aging 
Surface st nd rd th th
Resistivity 1  2  3  4  5  
Measurem Measure Measure Measure Measure Measure
Avera
ent (? /sq) ment ment ment ment ment 
ge 
 
C167CR 
carrier 1.68 x 105 1.6 x 108 1.51 x 108 1.52 x 108 1.77 x 108 1.62 x 8
tape 10  
ST10F276 
carrier 8.07 x 104 5.62 x 104 6.77 x 104 8.72 x 104 6.45 x 104 7.13 x 
tape 10
4 
XC2288H 
carrier 3.01 x 105 2.84 x 105 2.36 x 105 3.65 x 105 2.96 x 105 2.96 x 5
tape 10  
 
Figure 37 shows the graph of change in surface resistivity values for C167CR 
carrier tape after accelerating to aging conditions specified for run 1 and run 2. For both 
runs, C167CR carrier tape showed an increase of the mean value of surface resistivity 
75 
 
 
from 105 Ohms/Sq to 109 Ohms/Sq at the end of 28 days. This increase was significant 
compared to other carrier tapes and MBBs used in this thesis, and so they were 
continued to age beyond 28 days to observe if it reaches the failure criteria of >1012 
Ohms/Sq. However, the range of the surface resistivity values was observed to be 
stabilized after 28 days. The maximum values of surface resistivity did not increase 
beyond 1010 Ohms/Sq all through the 45 days of aging at conditions specified for both 
runs 1 and 2. The reason for the increase in surface resistivity value for C167CR carrier 
tape, unlike other carrier tapes, can be attributed to the different manufacturer of this 
carrier tape compared to the manufacturer of the ST10F276 and XC2288H carrier 
tapes. 
Figure 38 shows the graph of change in surface resistivity vs. aging time for 
ST10F276 carrier tape. For run 1, the range of values of surface resistivity did not 
increase beyond 105 Ohms/Sq at the end of 28 days, and so the experiments were 
suspended for ST10F276 carrier tape at run 1 conditions. For run 2, the mean value 
showed an increase from 105 to 106 Ohms/Sq at the end of 28 days. This increase was 
considered to be significantly less compared to the change in surface resistivity 
observed for C167CR carrier tape, and so the experiments were suspended for 
ST10F276 at run 2 conditions as well.  
The change in surface resistivity values for XC2288H carrier tape is shown in 
Figure 39. Both run 1 and run 2 showed a similar trend of varying - increasing and 
decreasing mean values of surface resistivity. However, the range of the values for the 
aging period of 28 days was found to be consistent, and so the accelerated aging 
76 
 
 
experiments were stopped from measuring the surface resistivity values for XC2288H 
carrier tape at the end of 28 days.  
 
Figure 37 Graph showing the change in surface resistivity of the C167CR carrier tape vs. aging time 
for different runs 
 
 
77 
 
 
 
Figure 38 Graph showing the change in surface resistivity of ST10F276x carrier tape vs. aging time for 
different runs 
 
 
Figure 39 Graph showing the change in surface resistivity of XC2288H carrier tape vs. aging time for 
different runs 
 
 
78 
 
 
Accelerated Aging Experiment for Change in Dimensions of Carrier Tape  
Polymeric shrinkage mechanism that could cause the dimensions of the carriers to 
change over time. This section details the accelerated aging experiments that were run 
to determine the criticality of the degradation mechanism by observing the change in 
dimensions of the carrier tape after aging.  
In this thesis, the diameter and pitch of the sprocket holes of the carrier tapes are 
the two dimensions that are evaluated to observe for any change after aging. The 
diameter and pitch are represented as D0  and P0, as shown in Figure 40. EIA 481-E has 
set the dimensional requirements for the diameter and pitch of the sprocket holes of the 
carrier tape that is shown in Table 25. To analyze the criticality of the polymeric 
shrinkage mechanism that causes the change in dimensions during the long-term 
storage, the carrier tapes were aged in a temperature/relative humidity chamber at two 
conditions ? 850C/5%RH and 600C/25%RH. The aging conditions and the run time 
have been tabulated in Table 26. A different set of carrier samples were used for each 
run, as shown in Figure 33. The dimensions ? diameter and pitch of sprocket holes of 
the carrier tapes were measured using the Zeiss Axiovert optical microscope.  Figure 
41 shows an optical microscopic image representing an example of a measurement of 
the diameter and pitch of the sprocket holes of a carrier tape. 4 different diameters of 
the sprocket holes were measured for each sample and for each time interval of each 
run, and the average was calculated. 2 different measurements of pitch between any 
two of the 4 different sprocket holes were measured for each sample and for each time 
interval of each run, and the average was calculated. The dimensions were measured 
79 
 
 
for every carrier tape before and after aging, and the percentage change in dimensions 
was calculated. It is hypothesized that upon aging at higher temperatures, the diameter 
increases, and pitch decreases due to the polymeric shrinkage. 
 
Figure 40 Picture showing the dimensions (D0  and P0) of the carrier tape as provided by EIA 481-E 
[37] 
 
Table 25 Dimensional requirements for carrier tape set by EIA standard 481-E 
Width (W) 44 mm 
Diameter of the Sprocket Holes (D0) 1.5 + 0.1 mm 
Pitch of the Sprocket Holes (P0) 4 ? 0.1 mm 
 
Table 26 Aging conditions and aging time for the experiments conducted for polymeric shrinkage 
mechanism 
 Run 1 Run 2 
Temperature/Relative 850C/5%RH 600C/25%RH 
Humidity Condition 
Run Time (Aging Period) 19 days  19 days  
Number of Samples 2 Pockets containing components from each carrier 
tape (Totally 6 pockets) 
80 
 
 
 
Figure 41 Optical microscopic image showing the measurement of pitch and diameter of sprocket 
holes 
Figure 42, Figure 43, Figure 44, and Figure 45 show the percentage change in 
dimensions ? diameter and pitch of the sprocket holes of different carrier tape samples 
used in this thesis for the conditions specified at run 1 and run 2. For the change in 
diameter graphs - Figure 42 and Figure 44, the solid line is drawn through the mean 
value of 4 different diameter measurements that were measured at each time interval 
for each carrier tape sample. For the change in pitch graphs - Figure 43 and Figure 45, 
the solid line is drawn through the mean value of the 2 different pitch measurements 
that were measured at each time interval for each carrier tape sample.  
 
When the carrier tape samples were aged at 850C/5%RH - run 1, the change in 
percentage of the diameter of the sprocket holes of the carrier tapes did not show a 
monotonous trend. It can be observed from Figure 42 that for run 1 at the end of 19 
days, the diameter of the sprocket holes of C167CR carrier tape increased from 1.598 
mm to 1.612 mm, ST10F276 increased from 1.56 mm to 1.585 mm, and XC2288H 
carrier tape increased from 1.533 mm and 1. 581 mm. Comparing with dimensional 
81 
 
 
requirements set by EIA 481-E standard for the diameter of the sprocket holes (1.4 mm 
? 1.6 mm) as shown in Table 25, the increase in diameter was observed to be within 
the upper limit specification except for ST10F276 carrier tape (1.612mm), which is a 
little above 1.6mm. However, this little increase in the diameter of the sprocket holes 
does not cause any feeding errors or mis-picks during the pick and place operation after 
long-term storage.  
Figure 43 shows the change in the pitch of the sprocket holes of the different carrier 
tapes for the run 1 condition for an aging period of 19 days. While it is hypothesized 
that the pitch of the sprocket holes is decreased upon aging, ST10F276 showed an 
increase in pitch from 4.045 mm to 4.053 mm. However, this increase is still within the 
upper limit (4.1 mm) of the pitch of the sprocket hole specification provided by EIA 
481-E. On the other hand, C167CR and XC2288H showed a decrease in the pitch from 
4.075 mm to 4.056 mm and from 4.069 mm to 4.058 mm, respectively. This decrease 
was also found to be within the lower limit specification (3.9 mm) for the pitch by the 
EIA 481-E standard. It can also be observed that similar to Figure 42, the graph of 
Figure 43 did not show any monotonous trend. 
For run 2 conditions, as shown in Figure 44, the change in diameter of the sprocket 
holes was found to show an increase in diameter of the sprocket holes above the upper 
limit specification provided by EIA 481-E. However, as already discussed, this little 
above 1.6 mm increase does not cause any feeding errors or mis-picks. Figure 45 shows 
the change in percentage values obtained for change in the pitch of the sprocket holes 
for different carrier tapes for run 2 conditions. None of the values at the end of 19 days 
82 
 
 
were observed to be outside the limits of the specifications provided by the standard. 
As the graphs did not show a monotonous trend, and the change were observed to be 
less critical for dimensions, the experiments were stopped from running at the end of 
19 days.  
 
Figure 42 Graph showing the change in percentage of the diameter of the sprocket holes vs. aging time 
for different carrier tape samples at running 1 condition 
 
83 
 
 
 
Figure 43 Graph showing the change in percentage of the pitch of the sprocket holes vs. aging time for 
different carrier tape samples at run 1 condition 
 
 
Figure 44 Graph showing the change in percentage of the diameter of the sprocket holes vs. aging time 
for different carrier tape samples at run 2 condition 
 
84 
 
 
 
Figure 45 Graph showing the change in percentage of the pitch of the sprocket holes vs. aging time for 
different carrier tape samples at run 2 conditions 
  
85 
 
 
Chapter 6: Discussion 
This section provides the discussion of the results obtained from the experiments 
conducted on MBBs, desiccants and carriers, that were provided in Chapter 5: 
Experiments and Results. The discussions include the method for obtaining the 
estimate of mass of water vapor adsorbed by desiccant sealed inside MBB vs. time and 
the estimate of RH inside MBB vs. time from the obtained experimental results.   
Method for Obtaining the Mass of Water Vapor Adsorbed by Desiccant vs. Time 
This section discusses the method for estimating the time to reach a certain 
percentage of adsorption capacity of desiccant when sealed inside MBB at a certain 
outside temperature / RH condition. This estimate is obtained by determining the 
relationship between the mass of water vapor adsorbed by desiccant and time. The 
method is explained for an example of MBB sealed with 16.5g of clay desiccant placed 
in an outside condition of 40 ?C / 93% RH.  
Equation (12) represents that MVTR equation, whose definition of terms and 
derivation are discussed in detail in moisture permeation property section. Here, ?? 
represents the mass of water vapor permeated through MBB in grams, ?? represents the 
area of the MBB through which the moisture permeates in m2, and ?? represents the time 
in days. The value of permeability, ??, at 40 ?C from Table 7 is 6.62E-7.   Relative 
humidity outside the MBB, ??????????, is 0.93. Relative humidity inside the MBB, ????????, 
is obtained from Figure 30 whose data was recorded from the wireless sensor placed 
inside MBB along with 16.5g of desiccant at 40 ?C / 93% RH as outside condition. 
86 
 
 
However, in this example, it is assumed that there is no water vapor present initially. 
As a result, Figure 30 is modified by removing the decrease in RH data from 0 to 4.5 
days that represents the adsorption of initial mass of water vapor present inside the 
MBB after sealing to obtain Figure 46. Area, A, and thickness, L, of the MBB are 0.07 
m2 and 0.11 ? 10-3 m respectively. Substituting ??, ??,??,?????????? ,???????? in equation (13) 
provides a linear relationship between the mass of water vapor permeated through 
MBB and time. Assuming that the moisture permeated through MBB is adsorbed by 
the desiccant, ?? in the equation (13) can be replaced by ????2?? representing the mass of 
water vapor adsorbed by desiccant. Also, assuming that the properties of MBB and 
desiccant may not degrade for the period of long-term storage, the linear relationship 
between the mass of water vapor adsorbed by desiccant and time when 16.5g of 
desiccant is inside sealed MBB at 40 ?C / 93% RH as outside condition is shown in 
equation (14). This linear relationship may hold true only till the desiccant inside sealed 
MBB reaches 80% of the desiccant?s adsorption capacity because the rate of adsorption 
gets slower and slower as the desiccant reaches its adsorption capacity, and it is not 
good to assume that it will still be linear after 80%. Using this equation, the time taken 
to reach 80% of the adsorption capacity of the desiccant at 40 ?C / 60% RH as inside 
condition, as determined from Table 14, is estimated to be approximately 18 years. 
Similarly, this method can be used for estimating the time taken by desiccant to reach 
the required percentage of adsorption capacity at a required outside temperature / RH 
condition.  
87 
 
 
?? ?? (12) 
???????? =  =  (?????????? ?  ????????) ?? ? ?? ??
Q = ?? (????  ?  ???? ) ? ?? ? ??  (13) 
?? ?????? ????
 ?? ?3?? ?? = 4.1 ?  10  ? ??  (14) 2
 
Figure 46 Graph showing the relative humidity inside MBB vs. Time recorded by wireless sensor 
inside MBB sealed with 16.5g of desiccant at 40 ?C / 93% RH (Modified version of Figure 43)  
Method for Estimating the RH Inside MBB vs. Time  
In this section, the method for obtaining the relationship between RH increase 
inside MBB and time when desiccant is inside sealed MBB based on equation obtained 
in Section: Method for Obtaining the Mass of Water Vapor Adsorbed by Desiccant vs. 
Time is discussed. The outcome of this method is to estimate the time taken to reach a 
certain level of RH inside MBB based on which engineering and managerial decisions 
for replacing the MBB and desiccants can be made. The method is shown for an 
example of MBB sealed with 16.5g of desiccant inside it with outside temperature / 
RH condition to be 40 ?C / 93% RH. The results estimated based on equation (14) is 
compared to validate against the theoretical results obtained from first principle 
moisture permeation and moisture adsorption equation.  
88 
 
 
Equation (14) provides the relationship between the mass of water vapor adsorbed 
by desiccant and time at 40 ?C / 93% RH as the outside condition. Equation (11) from 
adsorption isotherm section provides the adsorption isotherm equation for the desiccant 
at 40 ?C. Under equilibrium, the mass of water vapor, ????2??, in equations (14) and (11) 
are equated to obtain equation (15) that provides the relationship between RH inside 
MBB and time in days. The equation (15) is obtained based on the assumption that the 
RH inside the MBB initially (time of sealing) is zero.  
???? = 4.59 ?  10?6 ?  ??1.2 (15) 
The graph based on equation (15) is shown in Figure 47. The top subplot of the 
graph shows the relative humidity inside MBB vs. time and bottom subplot of the graph 
shows the mass of water vapor adsorbed by the desiccant vs. time correspondingly. The 
linear assumption for the mass of water vapor adsorbed by desiccant and time was made 
valid till the desiccant reaches 80% of its adsorption capacity at 40 ?C / 60% RH inside 
the MBB. The estimate of time taken to reach 80% of its adsorption capacity is 
approximately 18 years and the corresponding increase in RH inside MBB is around 
17.5% RH.  
89 
 
 
 
Figure 47 Graph showing two subplots - Top subplot shows the relative humidity inside MBB vs. time 
and the bottom subplot shows the corresponding mass of water vapor adsorbed by desiccant vs. time 
Taking 10% RH as the limit based on IPC/JEDEC J-STD-033 standard, from Figure 
48, the estimate of time taken to reach 10% RH inside the MBB is approximately 11 
years and the desiccant would have adsorbed approximately 47% of its adsorption 
capacity at 40 ?C / 60% RH. The humidity indicator card also indicates 5% RH level, 
and this 5% RH can also be taken as warning limit for the companies to taken 
engineering decisions and judgements for replacing the desiccants before it reaches 
10% RH inside MBB. The estimate for 5% RH is approximately 6 years and the 
desiccant would have adsorbed 26% of its adsorption capacity at 40 ?C / 60% RH. 
These estimates are obtained based on the equation (11) which was obtained from 
experiments. 
 
90 
 
 
 
Figure 48 Graph showing two subplots with estimates of time to reach 5% RH and 10% RH inside 
MBB, and corresponding mass of water vapor adsorb by the desiccant 
 
The estimated results obtained from the experiments conducted on MBBs and 
desiccants is compared against the theoretical results that can be obtained from 
equations for moisture permeation for MBB and moisture adsorption for desiccant. The 
first principle moisture permeation equation is obtained from equation (12). The 
moisture adsorption equation is obtained from equation (11). According to the 
conservation of mass, mass of water vapor permeated through MBB in equation (12), 
Q, is equal to the mass of water vapor adsorbed by the desiccant in equation(11), ????2??, 
plus the initial mass of water vapor in air inside the MBB, ???????????????? to obtain equation 
(16). Assuming that mass of water vapor initially inside the sealed MBB is zero, the 
equation (17) is obtained from which the theoretical increase in RH inside MBB can 
be obtained.  
?? +  ???????????????? = ???? (16) 2?? 
91 
 
 
??(??) ?  ?? (17) 
 ? (?????????? ?  ????????) ? ?? = 0.69 ? (???? )0.83???? ? ???? ????????
 
Figure 49 shows the theoretical results obtained from the equation and results 
obtained based on experiments conducted on MBBs and desiccants at 40 ?C / 93% RH. 
It can be observed from the graph that the theoretical results and the results based on 
experimental analysis diverge and the difference increases as the time increases. It can 
be inferred from this observation that the results based on experimental results can be 
considered as a conservative estimate compared to theoretical results because of linear 
assumption in experimental analysis. The theoretical results show that as the desiccant 
is approaching towards its adsorption capacity, the rate of adsorption becomes slower 
and slower and therefore a corresponding slower increase in RH. For reaching 5% RH, 
theoretical results show that it takes approximately 7 years, whereas results based on 
experimental analysis provide a conservative estimate of 6 years and correspondingly 
the desiccant adsorbs 26% of its adsorption capacity when it reaches 5% RH inside 
MBB. So this graph shows that both the theoretical and experimental methods can be 
used for obtaining estimates of time to reach 5% RH inside as the results are 
comparable for the lower levels of RH.   
92 
 
 
 
Figure 49 Graph showing the comparison of theoretical results and results based on experimental 
analysis for 
 
The theoretical results were obtained for 25 ?C / 60% RH as outside condition. 
From the graph, it can be observed, it takes 22 years to reach the 5% RH inside MBB 
at 25 ?C / 60% RH condition and correspondingly the desiccant adsorbs 20% of its 
capacity at 25 ?C / 60% RH. The reason for this longer time to reach 5% RH at 25 ?C 
/ 60% RH compared to 40 ?C / 93% RH results is because the permeation rate decreases 
with the decrease in temperature which reduces the amount of water vapor permeated 
through MBB from the outside to the inside environment. This results in slower 
adsorption rate by the desiccant and thus, slower increase in RH inside MBB. When 
the RH inside MBB reaches 5%, the desiccant is estimated to adsorb 20% of its 
adsorption capacity at 25 ?C / 60% RH.  
93 
 
 
 
Figure 50 Graph showing theoretical results for relative humidity inside MBB vs. time and mass of 
water vapor adsorbed by desiccant vs. time at 25 ?C / 60% RH as outside condition 
Table 27 Summary of results 
Estimate of time to reach 5% RH 
Condition inside MBB when 16.5g of Estimate of mass of 
(Temperature/ desiccant is inside the sealed water vapor adsorbed 
Relative MBB by 16.5g of desiccant 
Humidity) Theoretical Results Based on at 5% RH inside 
 Results Experimental MBB 
Analysis 
40 ?C / 93% RH 6 years 7 years 0.9g  
 (26% of desiccant?s 
adsorption capacity at 
40 ?C / 60% RH) 
25 ?C / 60% RH 22 years - 0.8g  
 (20% of desiccant?s 
adsorption capacity at 
25 ?C / 60% RH) 
 
Table 27 shows the summary of the results obtained in the thesis. For 40 ?C / 93% 
RH, the estimate of time to reach 5% RH inside MBB when 16.5g of desiccant is sealed 
inside MBB is 6 years, which is based on results obtained from experimental analysis, 
and 7 years from theoretical results. And the desiccant is estimated to adsorb 26% of 
94 
 
 
desiccant?s adsorption capacity when RH reaches 5% RH. For 25 ?C / 60% RH, 
theoretical results show an estimate of 22 years to reach 5% RH inside MBB and 20% 
of the desiccant adsorption capacity is estimated to be utilized when the RH reaches 
5% RH inside MBB. These results assume that MBB or desiccant may not undergo 
degradation till the time that has been reported here.  
  
95 
 
 
Chapter 7: Conclusions  
Companies undergo long-term storage to avoid the problem of component 
obsolescence. Long-term storage can be represented as a system containing 
replacements elements (packaging media) and non-replaceable elements (electronic 
components). The failure of long-term storage system is defined as when the electronic 
component?s (non-replaceable elements) manufacturability and reliability 
requirements are not met. Defining the system and its lifecycle environment allows for 
the identification of the long-term storage system?s various elements? degradation 
modes, mechanisms, and effects associated with it.   
Degradation modes such as change in surface resistivity and change in dimensions 
can be observed on carrier tapes of tape and reel during long-term storage of electronic 
components. However, experimental results showed no increase or decrease in surface 
resistivity or dimensions of the sprocket holes and pitch of the carrier tape beyond the 
maximum or minimum limits specified by the standards when aged at accelerated 
conditions (85 ?C / 5% RH and 60 ?C / 25% RH). At the warehouse, the carrier tapes 
are packed inside MBB that is maintained at a maximum temperature of 25?C. Also, 
the recommendation for maximum relative humidity inside MBB is 10% RH before 
the desiccants and MBBs shall be replaced. Since only minimal changes were observed 
at accelerated conditions, the degradation modes ? change in surface resistivity and 
dimension for the carrier tapes packed within MBB that is stored at <25?C / <10%RH 
inside MBB is concluded to be less critical to occur and affect the manufacturability or 
reliability of the electronic components. This conclusion holds good when the MBBs 
96 
 
 
and desiccants are replaced before the RH inside MBB reaches 10% RH. Change in 
surface resistivity degradation mode can also be observed on MBBs. Similar to the 
experiments conducted on carrier tapes to find criticality of this degradation mode, 
MBBs were also aged at accelerated conditions (85 ?C / 5% RH and 60 ?C / 25% RH) 
for observing its change in surface resistivity over time. The results of this experiment 
also led to the conclusion that the degradation mode of change in surface resistivity on 
MBBs when stored at <25?C / <10%RH inside MBB is found to be less critical to 
occur.  
Desiccants used for long-term storage of electronic components has got adsorption 
capacity beyond which the permeated moisture will not get adsorbed and as the 
desiccant is adsorbing the permeated moisture, the RH inside the MBB increases. It is 
critical to estimate the trend of RH increase inside MBB vs. time based on the 
permeation characteristics of MBB and adsorption characteristics of the desiccant that 
is inside sealed MBB. Methods developed in this thesis estimated that it takes 22 years 
to reach 5% RH inside MBB when 16.5g of desiccant is inside sealed MBB at 25 ?C / 
60% RH as outside condition. Similarly estimates for time to reach 5%RH inside MBB 
and the corresponding increase in mass of any desiccant can be obtained from the 
methods developed in the thesis ? which are based on experimental results and based 
on theoretical equations. These estimates can be used for determining replacement 
schedule for desiccants during long-term storage. However, these estimates were made 
on some assumptions. Therefore, it is recommended to introduce and distribute control 
samples for packaging media and inculcate periodic verification of those control 
samples as one of the management practices for long-term storage. Based on the 
97 
 
 
estimates obtained for time to reach 5% RH inside MBB, engineering and managerial 
decisions can be made to determine time interval for periodic evaluation of control 
samples. Also, if there any changes associated with mass measurement of desiccant at 
each time interval with the estimated trend developed by using the method proposed in 
the thesis, appropriate decisions and actions need to be taken.  
As a part of risk management practices for long-term storage, storage conditions 
such as temperature and relative humidity for high-risk elements - components or the 
packaging media should be determined, based on which the changes should be made 
accordingly for the next level of assemblies, such as circuit cards and modules. The 
storage policies followed by the component manufacturers and distributors need to be 
obtained for determining the pre-storage stress factors. It is important to know how 
long the components and packaging media have been stored in the component and 
packaging media manufacturer's and distributor's warehouses so that the time to replace 
estimate can be adjusted accordingly. Any qualification reports, product change 
notifications (PCNs), and product discontinuation notifications (PDNs) available for 
the packaging media should also be obtained. Care should also be taken in not selecting 
any substandard or non-conforming MBBs, carriers, desiccants, and humidity indicator 
cards for long-term storage of electronic components. 
  
98 
 
 
Chapter 8: Appendices 
Appendix A ? Elements of Long-Term Storage System 
Carriers 
Carriers are packaging media that are used to protect the components from physical 
damage and electrostatic discharge damage during transportation and storage. 
Electronic components such as, but not limited to, transistors, capacitors, resistors, 
diodes, and integrated circuits are protected by placing and containing them within the 
carriers. In addition to the function of protecting the components from physical and 
environmental damage, they are used as an aid in the manufacturing or assembly 
processes after storage. For example, carriers containing the integrated circuits such as 
microprocessors are fed along the rails of the pick and place machines that 
automatically pick those microprocessors from the carriers and place it in a specific 
orientation at a specific location on the circuit board for reflow soldering. In general, 
carriers can be categorized into three types ? tube, tray, and tape and reel.  
Tubes 
Tube carriers also called stick magazines, are an elongated hollow body made of 
plastic with antistatic coating, extruded in a rectangular shape. Each end of the tube is 
provided with a stopper to hold the components inside the tube and thus preventing 
them from falling out of the tube during transportation. They are used to feed the 
components to automatic pick and place machines for surface and through-hole board 
99 
 
 
mounting [5]. Figure 51 shows the picture of tube carriers containing quad flat node 
(QFN) package components inside it.  
 
Figure 51 Tube carrier containing quad flat node (QFN) package components  
Tray 
Tray carriers are molded in rectangular shapes that nest the electronic components 
within a matrix of pockets that are uniformly spaced. Figure 52 shows the picture of a 
tray carrier. Trays are primarily designed for leaded components that require 
component lead isolation during transportation, handling, and manufacturing/assembly 
of those components. Unlike the tube carriers, the tray pockets prevent the component?s 
leads from coming into contact with each other, thus protecting the components from 
physical damage during transportation and storage. The spacing provides exact 
locations for industry-standard automated-assembly equipment used for pick-and-place 
in board-assembly processes [41]. There are specific standards formulated by the 
electronic industries alliance (EIA) and joint electron device engineering council 
(JEDEC) that outlines requirements to store and handle the trays effectively. JEDEC 
publication 95 ? Design guide 4.10 provides the standard design requirements for trays 
[42]. EIA 948 and EIA 960-B provides the requirements for automatic handling of trays 
100 
 
 
during the pick and place operations [43] [44]. They are usually of two types ? bakeable 
and non-bakeable trays. With the bakeable trays, the components can be baked along 
with the trays inside the oven without having the components involved with any risk 
of damage due to additional handling. On the other hand, components have to be picked 
out of the non-bakeable trays for baking, which increases the chance of physical 
damages due to handling. The commonly used materials for manufacturing tray carriers 
in the current market are polyvinyl chloride, polystyrene, polyethylene terephthalate, 
polypropylene, and polycarbonate. The choice of material selection for the trays is 
based on the requirement of the maximum temperature rating. Trays are usually 
shipped in stacks of multiple single trays placed on top of each other for rigidity. These 
stacked trays that are loaded with components are protected with an empty cover tray 
on the top. Typically, the stack configurations are either five fully loaded trays with 
one empty cover tray or ten fully loaded trays with one cover tray [41]. Figure 53 shows 
the picture of stacked trays. The advantages of using the trays are attributed to its easy 
inspection of the loaded components and its reduced weight, thus reduced shipping 
cost.  
 
101 
 
 
 
Figure 52 Tray carriers with pockets and loaded with Plastic Quad Flat Package (PQFP) components 
 
 
Figure 53 Trays stacked with the configuration of 10 loaded trays and one empty cover tray at the top 
Tape and Reel 
In tape and reel carriers, the electronic components are loaded onto a tape with 
sequential cavities along its length that are either in the form of punched holes or 
embossed pockets. This tape, known as carrier tape, is wound around a reel to feed the 
components for automatic pick and place operations for surface mounting on board 
102 
 
 
assemblies. The carrier tape is sealed by a cover tape on one side for embossed pockets 
and on both sides, for cavities to hold and retain the components, thus protecting the 
components from any physical damage and also free from dust and contaminants. The 
three elements of the tape and reel are carrier tape, cover tape, and reel. In general, the 
tape and reel carriers are categorized into two types based on the type of cavity found 
in carrier tape ? punched hole type and embossed pocket type. In the former type, 
carrier tapes are punched with sequential holes to contain components, whereas, in the 
latter type, the carrier tapes are embossed in the form of pockets of a certain thickness 
to hold the components. Figure 54 shows the tape and reel, its elements, and its two 
types based on the cavity. Standards such as EIA 481?E formulated by automated 
component handling committee (ACH) of electronic components industry association 
(ECIA) in 2015 and IEC 60286-3 formulated by International Electrotechnical 
Commission (IEC) in 2019 provide specific requirements to store, handle, tape and de-
tape the surface mount components effectively. They also provide dimensional 
requirements for the carrier tapes that, if not adhered to, may cause functional problems 
with the industry-standard automated feeding systems. 
One important dimensional characteristic of the carrier tape is camber, which is 
defined as the curvature of the tape with respect to the x and y-axis on the plane in 
which the carrier tape is fed parallelly to the guideways. Camber shall not exceed 1 mm 
over 250 mm in either direction when the carrier tape is fed into guideways. Figure 55 
shows this dimensional requirement for camber in carrier tapes [37] [45]. The standards 
also proposed general and storage requirements for the carrier tapes. Along with these 
103 
 
 
standards, EIA 468-C provides requirements for dimensions and tolerances for the 
automatic handling of components having two or more radial configured leads [46]. 
 
Figure 54 Two types of tape and reel along with its elements 
 
 
Figure 55 Dimensional requirement of camber in carrier tapes 
 
Carrier Tape of Tape and Reel Carrier 
The carrier tape is a continuous tape wound around the reel to accommodate 
electronic components for transport, storage, and automatic feeding to pick and place 
machines. These tapes incorporate sprocket holes that are punched on one or both the 
side ends of the tape depending on the tape width. These sprocket holes index with the 
sprockets of the pick and place machines to drive them along the guideways for 
104 
 
 
automatic feeding. Figure 56 shows the setup of the carrier tape containing components 
sliding along the guideways of the pick and place machine. Usually, the punched hole 
type carrier tapes contain small passive electronic components with thickness less than 
0.9 mm approximately, for example, chip resistors and capacitors. The material that is 
commonly used for manufacturing the punched hole type is paper. The reason for using 
paper is because it does not require a high level of protection from physical damage 
during the transportation of passive components compared to the active leaded ICs. 
Components with thickness greater than 0.9 mm require more rigid protection from 
physical damage and ESD, and so they are loaded onto carriers with embossed pockets. 
This embossed pocket type carrier tapes are commonly made up of polymers such as 
polystyrene and polycarbonate. Some of the factors that influence the choice of 
selecting the materials for carrier tapes include susceptibility to warping and bending, 
risk of rough feeding into pick and place machine that may result in mis-pick errors, 
and, the requirement of tighter tolerances with dimensional integrity to restrict 
movement - rotation and tilting within the pocket that may otherwise result in physical 
damage of the leads and mis-picks [47]. 
105 
 
 
 
Figure 56 Carrier tape setup along the guideways of the pick and place machine for automatic 
component handling 
 
Cover Tape of Tape and Reel Carrier 
Cover tape is an antistatic, transparent polymeric thin film coated with the adhesive 
layer. The cover tapes are adhered to the top of carrier tapes after the components are 
loaded onto them, to protect and contain the loaded components during transportation 
and storage. During the automatic feeding operation of the carrier tapes along the 
guideways, the adhered cover tapes are peeled back using a peeling machine followed 
by pick and place operation of the contained components. Figure 57 shows the picture 
of cover tape adhered to the carrier tape along with the picture of cover tape peeled 
back from the carrier tape. Cover tapes are generally categorized into two types ? heat-
activated and pressure-sensitive. In heat-activated cover tapes, temperature, time and 
pressure are the parameters that are controlled in the sealing machine to adhere to the 
cover tape onto the edges of the carrier tape on both sides, sealing the cover tape to the 
carrier tape. Though these are the most widely used type of cover tape in the industry, 
it is marked with a downside of relatively inconsistent peel force compared to its 
counterparts. This uneven peel force causes the devices to pop out of their positions 
106 
 
 
within the pockets of the carrier tape, and this phenomenon is called as a trampoline 
that significantly slows down the production. On the contrary, the pressure-sensitive 
cover tape is adhered to the carrier tape by controlling the parameters such as pressure 
and time. These tapes provide smoother peel force and minimize the trampoline of 
components. However, these tapes leave behind a residue while peeling that builds up 
over time and causes jamming of the automatic feeder [47] [48].  
  
Figure 57 Picture showing the adhered and back peeled cover tape 
 
Humidity Indicator Cards 
Humidity indicator card (HIC) is an indicator of relative humidity (RH) levels 
inside the sealed moisture barrier bag that contains the components, carriers, and 
desiccants. The card is impregnated with certain chemicals that are sensitive to 
moisture, resulting in the change of color when the RH level exceeds the indicated 
level. This change in color allows for immediate inspection of RH level inside the bag; 
107 
 
 
however, the bag has to be cut open to inspect the RH level, which increases the risk 
of additional handling and processes such as vacuuming and re-sealing the bag. 
Typically, HIC is manufactured based on the compliance with IPC/JEDEC standard J-
STD-033 and military standard MIL-I-8835A. According to IPC J-STD-033D, HIC 
should have three spots indicating 5% RH, 10% RH, and 60% RH in blue color initially. 
When the RH level exceeds these indicated values, the spot corresponding to that value 
changes its color from blue to pink, and in some cases, the changed color migrates out 
of the spot. The 5% RH and 10% RH indicator are assigned to moisture sensitivity level 
(MSL) 2A-5A components, and 60% RH indicator is assigned to MSL 2 parts. If the 
10% RH spot is not blue for the MSL 2A-5A components that are sealed inside the bag, 
baking should be performed. If the 60% RH spot is not blue for the MSL 2 components, 
baking should be performed. Figure 58 shows the images of the HIC that comply with 
IPC/JEDEC J-STD-033D [39]. Table 28 shows the color indication of HIC that 
complies with IPC/JEDEC J-STD-033D at different RH environment.  
 
108 
 
 
 
Figure 58 HIC that complies with J-STD-033D 
 
Table 28 Color indication by HIC at different RH environment 
 Indicati Indication Indication Indication Indication Indication 
on at at 5% RH at 10% at 55% at 60% at 65% 
2% RH Environm RH RH RH RH 
Environ ent Environm Environm Environm Environm
ment ent ent ent ent 
5% Blue  Lavender Pink Pink Pink Pink 
Spot 
10% Blue Blue Lavender Pink Pink Pink 
Spot 
60% Blue Blue Blue Blue Lavender Pink 
Spot 
 
  
109 
 
 
Appendix B ? Material Property Testing, Analysis and Validation 
This section details the experiments that were conducted to test and validate some 
of the material properties of the received MBB samples.  
Moisture Barrier Bag  
Cross-Sectional Analysis ? Thickness Measurement 
The Dri-Shield 3700 series MBB was cut into a small strip from forming a V-shape 
to clearly identify the inner and the outer layers. The strip was then potted into a round 
shape with the V-shaped MBB strip showing its cross-section. The bottom side of the 
potted samples were then ground and polished to make a flat and clear cross-sectional 
view under the Zeiss Axiovert optical microscope. Figure 59 shows the V-shaped cross-
sectional image obtained from the optical microscope that clearly identifies the three 
layers of the MBB. The thickness of each layer of the MBB was measured three times 
and their average was taken. The thickness of the MBB as a whole was measured using 
the same optical microscope and its average was calculated. Table 29 shows the values 
of the measured thickness with its last row indicating the thickness measured for the 
whole MBB. The last row of the Table 29 was measured independently and is not the 
addition of the thickness of the three layers. On an average the thickness of the MBB 
was found to 115.47 microns which is within the tolerance limits provided by the 
manufacturer (Refer Table 3). Also, the thickness of the outer layer of the MBB was 
found to be less in value compared to the inner layer of the MBB. 
110 
 
 
Table 29 Thickness of each layer of the MBB and the whole MBB in microns 
 1
st 2nd 3rd 
Measurement Measurement Measurement Average 
Outer Layer (?m) 34.98 35.09 36.72 35.60 
Middle Layer (?m) 9.8 10.6 10.61 10.34 
Inner Layer (?m) 67.05 67.32 69.77 68.05 
MBB (Measured 
independently and 
not the addition of 114.92 115.34 116.15 115.47 
the three layers) 
(?m) 
 
 
 
Figure 59 Optical microscopic image showing the cross-section of the MBB 
 
Fourier Transform Infrared Spectroscopy (FTIR) Analysis 
FTIR analysis was performed to identify and validate the inner and outer polymeric 
layers of the MBB. Agilent Cary 670 FTIR spectrometer in attenuated total reflection 
(ATR) mode was used for FTIR analysis of the Dri-Shied 3700 series MBBs. The MBB 
111 
 
 
samples was cut into rectangular shape of dimensions 2.5*1 cm2. Infrared beam was 
allowed to through the diamond ATR crystal at different frequencies. The spectral 
output from FTIR was displayed in the form of graph with wavenumber along the x-
axis and the absorbance along the y-axis. FTIR spectra was obtained for both the inner 
and the outer layers of the MBB to validate the polymeric materials as specified by the 
manufacturer. 
(FTIR image obtained without any comparison with the FTIR library spectra has 
been included in the appendix section for now. The FTIR graph will be included after 
comparing the spectra with the library) 
Energy-Dispersive X-ray Spectroscopy (EDS) Analysis 
EDS analysis was performed to identify and validate the middle layer of the MBB. 
Similar to the sample preparation for the cross-sectional analysis, the MBB samples 
were cut into a V-shape and then ground and polished to view under the microscope of 
energy-dispersive x-ray spectrometer. The electron beam from the spectrometer was 
focused on the middle layer to obtain the elemental composition spectra from the EDS. 
Figure 60 shows the EDS spectra obtained for the middle layer of the MBB. The left 
side of the Figure 60 shows the point where the electron beam of the EDS was focused. 
The right side of the Figure 60 shows the EDS spectra with Aluminum as the major 
composition of the middle layer of the MBB, thus acting as a validation to the material 
specification provided by the Dri-Shield 3700 series manufacturer. Small traces of 
Carbon and Oxygen were also observed. The presence of Carbon in the middle layer 
can be attributed to the transfer of small amounts of Carbon from outer and inner 
112 
 
 
polymeric layers while grinding the sample. The possible explanation for the presence 
of small traces of Oxygen is that the Aluminum could have quickly reacted with the 
Oxygen present in the atmosphere to form Aluminum Oxide during the sample 
preparation.  
 
Figure 60 Figure showing the EDS spectra obtained for the middle layer of the MBB 
 
Surface Resistance Analysis 
The surface resistance of the MBB samples were measured using Signatone Pro-4 
Four Point Resistivity System to validate the surface resistance property of the MBB. 
The Pro-4 system measures the surface resistivity which is different from surface 
resistance. The surface resistance (Rs) is defined as the ratio of a DC voltage (U) to the 
current (Is) flowing between the two electrodes of specified configuration that are in 
contact with the same side of the material under test. On the other hand, surface 
resistivity (?s) is defined as the ratio of DC voltage (U) per unit length (L) to the surface 
current (Is) per unit width (D) [49]. The physical unit of surface resistivity (?s) is Ohm 
(?). The physical unit of the surface resistance (Rs) is also Ohm (?). In order to 
differentiate between the two, surface resistivity is often expressed in Ohm/square 
113 
 
 
(?/sq) though it is not a valid physical unit from the dimensional analysis point of view. 
Equation (18) and equation (19) in combination with Figure 61 provides the 
interpretation of the difference between the surface resistance and resistivity 
respectively in the equation form. According to ANSI/ESD STM 11.11, surface 
resistance measured using the test method specified in this standard can be converted 
into surface resistivity by multiplying a conversion factor of 10, which is derived from 
the fixed geometry of the electrode assembly [50]. As shown in the Table 3, the 
reported surface resistance property was measured according to ANSI/ESD STM11.11. 
As a result, the surface resistance value of 1 x 104 to < 1 x 1011 Ohms can be converted 
into its equal surface resistivity of 1 x 105 to < 1 x 1012 Ohms/square by multiplying it 
with a conversion factor of 10. The converted surface resistivity property of the MBB 
still lies within the region of static dissipative region.  
?? (18) 
?????????????? ???????????????????? ,????(?) =  ????
????? (19) 
?????????????? ??????????????????????, ???? (??????) = ?????
 
??  
114 
 
 
19 
 
Figure 61 Image showing the basic setup for measuring the surface resistance or resistivity 
 
  
115 
 
 
Appendix C ? Calibration Information of the Equipment  
This section provides the calibration information of the equipment, devices and 
machines used in this thesis.  
Weighing Scale  
Amir digital kitchen weighing scale was used for measuring the weight of the 
desiccants in the experiments that were performed to determine the moisture adsorbing 
capability of the desiccants above 500C. The scale was calibrated before used for 
measuring the weights of the desiccant. For calibrating the scale, known weights of 
mass 20g, 50g, 100g and 200g were taken and placed on the weighing scale. It was 
observed that the weighing scale displayed the mass without any error.  shows the 
picture showing the weighing scale displaying the exact mass of the known weights.  
 
Figure 62 Picture showing the calibration of weighing scale used in the experiments 
 
Temperature/Relative Humidity Chamber  
ESPEC Temperature/relative humidity chambers were used for the  aging 
experiments of MBBs and desiccants. The chambers were checked for calibration by 
116 
 
 
placing the Elitech wireless TH sensor inside them. Figure 63 shows the readings of 
the wireless TH sensor when the chamber was set at 600C/60% RH and 400C/60%RH.  
Temp/RH Readings of the Chamber from Wireless Sensor
70 70
60 60
50 50
40 40
30 30
20 20
Temperature
10 10
Relative Humidity
0 0
0 100 200 300 400
Time (minutes)
 
Figure 63  Graph showing the temperature and relative humidity of the chamber when set at 
600C/60%RH and 400C/60%RH 
  
117 
 
 
Temperature (0C)
Relative Humidity (%)
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