IEC 62435-8:2020

IEC 62435-8 ®
Edition 1.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electronic components – Long-term storage of electronic semiconductor
devices –
Part 8: Passive electronic devices

Composants électroniques – Stockage de longue durée des dispositifs
électroniques à semiconducteurs –
Partie 8: Dispositifs électroniques passifs

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IEC 62435-8 ®
Edition 1.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electronic components – Long-term storage of electronic semiconductor

devices –
Part 8: Passive electronic devices

Composants électroniques – Stockage de longue durée des dispositifs

électroniques à semiconducteurs –

Partie 8: Dispositifs électroniques passifs

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.020 ISBN 978-2-8322-8560-2

– 2 – IEC 62435-8:2020 © IEC 2020
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Storage considerations . 9
4.1 Overview of passive components . 9
4.2 Failure mechanisms . 9
4.2.1 Occurrence of failure and driving force . 9
4.2.2 Storage environment and mitigation for stimuli to prevent failure . 11
4.3 Materials management . 11
4.4 Storage media . 12
4.5 Documentation/paper lot identifiers . 12
4.6 Inventory check. 12
4.7 Inventory dry packing refreshing . 12
4.8 Inventory re-assessment . 13
5 Baseline long-term storage requirements . 13
5.1 General . 13
5.2 Moisture sensitivity designation . 13
5.3 Dry packing for storage . 13
5.4 Non-moisture sensitive storage . 13
5.4.1 General . 13
5.4.2 Storage media . 13
5.4.3 Lot data and labelling . 13
5.5 Storage of moisture sensitive finished devices . 14
5.5.1 Moisture barrier bag . 14
5.5.2 Dunnage . 14
5.5.3 Humidity indicator card . 14
5.5.4 Desiccant . 14
5.5.5 Labelling . 14
5.5.6 Lot data and labelling . 15
5.5.7 Storage environment . 15
5.5.8 Process (temperature) sensitivity designation . 15
Annex A (informative) Passive electronic device storage environment considerations . 16
Bibliography . 17

Table 1 – Failure mechanisms in storage and stimuli to mitigate during storage. . 10
Table 2 – Long-term environment – sustained condition requirements . 11
Table 3 – Considerations for management, control and documentation during storage . 12
Table A.1 – Long-term storage environment – sustained condition considerations . 16

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC COMPONENTS – LONG-TERM STORAGE
OF ELECTRONIC SEMICONDUCTOR DEVICES –

Part 8: Passive electronic devices

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62435-8 has been prepared by subcommittee IEC technical com-
mittee 47: Semiconductor devices.
The text of this International Standard is based on the following documents:
CDV Report on voting
47/2595/CDV 47/2618/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – IEC 62435-8:2020 © IEC 2020
A list of all the parts in the IEC 62435 series, published under the general title Electronic
components – Long-term storage of electronic semiconductor devices, can be found on the
IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
INTRODUCTION
This document applies to the long-term storage of passive electronic components.
This is a standard for long-term storage (LTS) of electronic devices drawing on the best long-
term storage practices currently known. For the purposes of this document, LTS is defined as
any device storage whose duration can be more than 12 months for product scheduled for
long duration storage. While intended to address the storage of unpackaged semiconductors
and packaged electronic devices, nothing in this document precludes the storage of other
items under the storage levels defined herein.
Although it has always existed to some extent, obsolescence of electronic components and
particularly of integrated circuits, has become increasingly intense over the last few years.
Indeed, with the existing technological boom, the commercial life of a component has become
very short compared with the life of industrial equipment such as that encountered in the aer-
onautical field, the railway industry or the energy sector.
The many solutions enabling obsolescence to be resolved are now identified. However, se-
lecting one of these solutions should be preceded by a case-by-case technical and economic
feasibility study, depending on whether storage is envisaged for field service or production,
for example:
• remedial storage as soon as components are no longer marketed;
• preventive storage anticipating declaration of obsolescence.
Taking into account the expected life of some installations, sometimes covering several dec-
ades, the qualification times, and the unavailability costs, which can also be very high, the
solution to be adopted to resolve obsolescence should often be rapidly implemented. This is
why the solution retained in most cases consists in systematically storing components which
are in the process of becoming obsolescent.
The technical risks of this solution are, a priori, fairly low. However, it requires perfect mastery
of the implemented process and especially of the storage environment, although this mastery
becomes critical when it comes to long-term storage.
All handling, protection, storage and test operations are recommended to be performed ac-
cording to the state of the art.
The application of the approach proposed in this document in no way guarantees that the
stored components are in perfect operating condition at the end of this storage. It only com-
prises a means of minimizing potential and probable degradation factors.
Some electronic device users have the need to store electronic devices for long periods of
time. Lifetime buys are commonly made to support production runs of assemblies that well
exceed the production timeframe of its individual parts. This puts the user in a situation re-
quiring careful and adequate storage of such parts to maintain the as-received solderability
and minimize any degradation effects to the part over time. Major degradation concerns are
moisture, electrostatic fields, ultraviolet light, large variations in temperature, air-borne con-
taminants, and outgassing.
Warranties and sparing also present a challenge for the user or repair agency as some sys-
tems have been designated to be used for long periods of time, in some cases for up to
40 years or more. Some of the devices needed for repair of these systems will not be availa-
ble from the original supplier for the lifetime of the system or the spare assembly may be built
with the original production run but then require long-term storage. This document was devel-
oped to provide a standard for storing electronic devices for long periods of time. For storage

– 6 – IEC 62435-8:2020 © IEC 2020
of devices that are moisture sensitive but that do not need to be stored for long periods of
time, IEC TR 62258-3 can be consulted.
Long-term storage assumes that the device is going to be placed in uninterrupted storage for
a number of years. It is essential that it is useable after storage. Particular attention should be
paid to storage media surrounding the devices together with the local environment.
These guidelines do not imply any warranty of product or guarantee of operation beyond the
storage time given by the manufacturer.
The IEC 62435 series is intended to ensure that adequate reliability is achieved for devices in
user applications after long-term storage. Users are encouraged to request data from suppli-
ers to applicable specifications to demonstrate a successful storage life as requested by the
user. These standards are not intended to address built-in failure mechanisms that would take
place regardless of storage conditions.
These standards are intended to give practical guide to methods of long-duration storage of
electronic components where this is intentional or planned storage of product for a number of
years. Storage regimes for work-in-progress production are managed according to company
internal process requirements and are not detailed in this series of standards.
The overall standard is split into a number of parts. Parts 1 to 4 apply to any long-term stor-
age and contain general requirements and guidance, whereas Parts 5 to 9 are specific to the
type of product being stored. It is intended that the product specific part should be read
alongside the general requirements of Parts 1 to 4.
Electronic components requiring different storage conditions are planned to be covered sepa-
rately starting with Part 5.
The structure of the IEC 62435 series as currently conceived is as follows:
Part 1 – General
Part 2 – Deterioration mechanisms
Part 3 – Data
Part 4 – Storage
Part 5 – Die and wafer devices
Part 6 – Packaged or finished devices
Part 7 – MEMS
Part 8 – Passive electronic devices
Part 9 – Special cases
ELECTRONIC COMPONENTS – LONG-TERM STORAGE
OF ELECTRONIC SEMICONDUCTOR DEVICES –

Part 8: Passive electronic devices

1 Scope
This part of the IEC 62435 series on long-term storage is applied to passive electronic devic-
es in long-term storage that can be used as part of obsolescence mitigation strategy. Long-
term storage refers to a duration that can be more than 12 months for product scheduled for
storage. Storage typically begins when components are packed at the originating supplier
where the pack date or date code are assigned to the product. It is the responsibility of the
distributor and the customer to control and manage the aging inventory upon receipt of the
dated product. Alternatively, a supplier-customer agreement can be established to manage
the aging inventory. Philosophy, good working practice, and general means to facilitate the
successful long-term storage of electronic components are also addressed.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their con-
tent constitutes requirements of this document. For dated references, only the edition cited
applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60749-20, Semiconductor devices – Mechanical and climatic test methods – Part 20: Re-
sistance of plastic encapsulated SMDs to the combined effect of moisture and soldering heat
IEC 60749-20-1, Semiconductor devices – Mechanical and climatic test methods – Part 20-1:
Handling, packing, labelling and shipping of surface-mount devices sensitive to the combined
effect of moisture and soldering heat
IEC 61760-4, Surface mounting technology – Part 4: Classification, packaging, labelling and
handling of moisture sensitive devices
JEDEC J-STD-075, Classification of non-IC electronic components for assembly processes
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following ad-
dresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
passive, adj
qualifies a circuit element or a circuit for which the time integral of
the instantaneous power cannot be negative over any time interval beginning at an instant
before the first supply of electric energy
EXAMPLE Resistor, inductor, capacitor, fuse, magnetic switch, crystal oscillator, diode, led

– 8 – IEC 62435-8:2020 © IEC 2020
Note 1 to entry: Under periodic conditions, the integration interval can comprise an integral number of periods
instead of beginning at minus infinity.
Note 2 to entry: A passive circuit normally does not contain voltage or current sources.
[SOURCE: IEC 60050-131:2002, 131-11-34, modified – A domain has been specified at the
beginning of the definition and some examples have been added.]
3.2
storage environment
specially controlled storage area, with particular control of temperature, humidity, atmosphere
and any other conditions depending on the product requirements
[SOURCE: IEC 62435-1:2017, 3.1.1]
3.3
critical moisture limit
maximum safe equilibrium moisture content for a specific encapsulated device at reflow as-
sembly or rework
3.4
long-term storage
LTS
planned storage of components to extend the life-cycle for a duration with the intention of
supporting future use
Note 1 to entry: Allowable storage durations will vary by form factor (e.g., packing materials, shape) and storage
conditions. In general, long-term storage is longer than 12 months.
[SOURCE: IEC 62435-1:2017, 3.1.2]
3.5
LTS storeroom
area containing components that have additional packaging for storage to protect from mois-
ture or from mechanical impact or for ease of identification or handling
3.6
moisture-sensitive device
MSD
device that has moisture absorption or moisture retention and whose quality or reliability is
affected by moisture
3.7
electronic device
packaged electrical, electronic, electro-mechanical (EEE) item, or assemblies using such
items
[SOURCE: IEC 62435-1:2017, 3.1.3]
3.8
desiccant
hygroscopic substance used to remove moisture from an atmosphere
3.9
moisture barrier bag
MBB
storage bag manufactured with a flexible laminated vapour barrier film that restricts the
transmission of water vapour
Note 1 to entry: Refer to IEC 60749-20-1 for packaging of moisture sensitive products.

[SOURCE: IEC 62435-1:2017, 3.1.4]
3.10
humidity indicator card
HIC
card printed with a moisture sensitive chemical that changes from blue to pink in the presence
of water vapour
[SOURCE: IEC 62435-1:2017, 3.1.5, modified – The bracketed information "(cobalt bromide)"
has been removed from the definition.]
3.11
water vapour transmission rate
WVTR
measure of permeability of MBBs to water vapour
3.12
dunnage
all the matter stored in a moisture barrier bag that is additional to the packaged electronic
component
3.13
electro-static discharge
ESD
transfer of electric charge between bodies of different electrostatic potentials in proximity or
through direct contact
[SOURCE: IEC 60050-561:2014, 561-03-06]
4 Storage considerations
4.1 Overview of passive components
Passive components are not able to control current where the instantaneous power cannot be
negative therefore there is no power gain before the application of electric energy. Common
examples of passives are resistors, capacitors, inductors, transformers and diodes of all
types. Often electromechanical relays, quartz crystals and fuses are also to be considered
passive components for the purpose of long-term storage requirements. Passive components
are made using a wide range of technologies, materials and manufacturing processes.
Passive components are surface mounted to electronic packages, modules and boards as ei-
ther discrete components or packaged components that vary in size, typically larger than
1 mm in the smallest dimension. Passive miniaturization has led to packaged passives. Pas-
sives are also integrated or embedded into other packaged components, modules and boards.
Passive components can experience many of the same failure modes as other components
and the storage program should consider the end use and failure mechanisms related to the
function of the component. An example list below may be used as a basis for consideration in
storage related risk assessments.
4.2 Failure mechanisms
4.2.1 Occurrence of failure and driving force
Failures during long-term storage should be mitigated by control of the stimuli driving given
failure modes of interest as defined by a failure modes and effects analysis (FMEA). Storage
related failures are often detected as modes of non-operation, visual quality or other non-
conformance. The modes of failure during storage are typically related to a failure mechanism

– 10 – IEC 62435-8:2020 © IEC 2020
that is driven by a physical stimuli or condition. Successful long-term storage is accomplished
by controlling the failure mechanism stimuli as identified using a failure modes and effect
analysis based on information from technology development and testing. Example failure
stimuli are given in Table 1. Additional examples of deterioration mechanisms are found in
IEC 62435-2. Successful long-term storage is accomplished by mitigating failures through
control of the stimuli or driving force.
Table 1 – Failure mechanisms in storage and stimuli to mitigate during storage.
Failure Failure mechanism detail Failure mode Mechanism stimuli
mechanism
Popcorn effect High rate vapour expansion Open circuit, blistering, com- Temperature increase lead-
within a passive during sur- ponent cracks or parametric ing to moisture vapour
face mounting electrical degradation
Handling Cracking Open, short, visible crack Application of force
damage
Visible scratch/smudge Open, short, surface mark Mechanical abrasion
Staining Change in surface appear- Visible defect, non- Exposure resulting in aging,
residue ance and specification result- conforming appearance and oxidation or hardening of
ing from unplanned exposure potential of misprocessing residue
to oxidizing contents
Polymer Polymer embrittlement Visible cracking, open or Temperature exposure, re-
material aging shorting or parametric deg- sidual mechanical stress
radation and bright light
Storage media Tape on reel or tube embrit- Misalignment during pro- Temperature exposure, me-
issues tlement/aging cessing chanical stressing and
bright light
Tube aging embrittlement Dropped parts from broken Temperature, handling and
tray media or parts out of bright light
formed pocket
Box aging embrittlement Dropped parts Temperature and bright light
Foreign material
ESD coating degradations Opens, shorts or parametric Triboelectric charging or
degradation from ESD charge potential difference
Label aging Illegible mark Bright light, temperature
Missing label Temperature and bright light
Brittle flaking – partial label Temperature and bright light
Indirect Moisture barrier bag leak Humidity indicator card trig- Handling abrasion, bending
material issues ger, visual non‑conformance and shock events
Humidity Indicator Card acti- Incorrect colour or no mois- Temperature, humidity Ex-
vated ture exposure indicated posure before use
Label aging Illegible mark Bright light, temperature
Missing label Temperature and bright light
Brittle flaking – partial label Temperature and bright light
Solderability Inability to form a good solder Post surface mount electrical Temperature, humidity Ex-
joint open or parametric shift posure
Corrosion Electro-chemical reaction Open, short, visual non- Temperature, galvanic cell,
leading failure or reduced conformance related sense chemical residue
mechanical functionality signal degradation or failure
Wear Degradation of functionality Sense signal degradation Mechanical cycling, dynamic
related to use of a mechanical stresses-vibration
function
Foreign Unexpected particle or other Sense signal degradation Mechanical cycling, dynamic
material material that prevents me- stresses-vibration
chanical functionality
Tin whiskers Whisker filament formed by Visual whiskers, short Bright Sn surface finish (un-
dislocations in metal films alloyed) crystal dislocation
with a gradient in surface growth (in un-mitigated
mechanical stress parts)
Sulphur gas catalysed reac-
tion
4.2.2 Storage environment and mitigation for stimuli to prevent failure
Mitigation of failures during and after long-term storage occurs by directly controlling or limit-
ing the stimulus for failure by a number of means. Common requirements for sustained long-
term storage are given in Table 2. Knowledge and control of the storage environment is of
primary importance to identify the risk of failure occurrence and to control or eliminate failure
stimuli during storage. Examples of the storage environment are contained in IEC 62435-4.
Other storage environment parameters related to long-term storage that may be important for
products or devices with certain sensitivities are presented in Annex A. It is the responsibility
of the end customer to maintain the storage environment as well as to ensure that terms and
conditions are in place successful long-term storage at the time of product purchase.
The full component thermal and environmental chain should be considered in planning relia-
bility characterization evaluation and for estimation of reliability after storage and added to the
use reliability estimates.
Table 2 – Long-term environment – sustained condition requirements
Storage environment Range Failure mitigation
(terrestrial storage)
a, b
Temperature controls or
Temperature
low/high: + 5 °C / + 40 °C
geographical placement
Relative Humidity (RH) Dry pack
low/high: 10 %/85 % RH
c
non-condensing
Shock and vibration Shock and vibration isola-
Specified by device manufacturer
tion
a
IEC 60721-3-1 storage classification 1K21
b
ASHRAE – climate control class A3 and class C for temperature
c
RH to be controlled: > 7 % is required for ESD control

Other storage environments of interest are: chemical activity, pressure, altitude and magnetic
fields. Other considerations are provided in Table A.1.
4.3 Materials management
Long-term materials storage management includes storage of identification data either in
physical form and/or in electronic form as determined by supplier/distributor and customer
agreement. It is required that classification, packaging, labelling and handling standards are
followed, per IEC 61760-4 to establish the storage start date and good provenance of the
components to be stored. Storage information for management, control and documentation
are shown in Table 3. The objective of data retention schemes is to identify discrepant mate-
rial either due to spoilage, mishandling, and originally undetected attributes and to maintain
chain of custody evidence to prevent counterfeit.

– 12 – IEC 62435-8:2020 © IEC 2020
Table 3 – Considerations for management, control and documentation during storage
Storage information Storage data Form or method
category
Data/aging Lot date code Box/bag date label, barcode/matrix code, physi-
cal mark.
Dry packing date
Environment deviations Alarms Box/bag date label and lot history, barcode/matrix
code, physical mark or database history
Qualifications Original qualification report Supplier/distributor report, report database
Inventory check report (if agreed)
Inventory requalification report
Extended storage justification

4.4 Storage media
The storage media refers to trays, tubes, tape-and-reel, bulk bag or other purpose-built pack-
aging for storage of finished products. Care should be taken to ensure the media does itself
not contain absorbed or adsorbed moisture, chemical contaminants or oils that can make their
way to the units being stored. Media can include dunnage used to secure the trays together
during handling and include tension bands and/or straps which are subject to the same re-
quirements as trays.
4.5 Documentation/paper lot identifiers
Lot information and documentation can be stored with units in LTS as a method to ensure unit
level and lot level identification during storage and prior to use. Lot information recorded on
paper and electronic devices are subject to the same restrictions for absorbed or adsorbed
moisture, chemical contaminants or oils that can provide stimuli for failure of parts upon final
assembly.
4.6 Inventory check
Inventory checking should be accomplished by either passive or active means depending up-
on business needs and terms of the obligation. Passive inventory checks are advantageous to
ensure proper accounting and minimal added handling.
Added handling, in the case of active checking, introduces additional risk to parts by un-
intended exposure or damage. Examples of unintended damage include: damage to moisture
barrier bags resulting in a leak detected at a later time as well as electrostatic discharge
which can be detected at system integration at a later time. A special case of inventory check
can be necessary when a new test program or manufacturing issue is detected and found to
affect stored inventory. The supplier can determine to manage the process proactively as an
issue is uncovered or passively prior to shipment to the customer. It is the responsibility of the
supplier or distributor to manage the inventory to the performance specification sheet and the
terms and conditions of the business agreement.
Added handling during an active inventory check and re-assessment is a practice that should
be properly planned and executed to prevent handling damage, electrostatic discharge and
violation of ambient moisture exposures.
4.7 Inventory dry packing refreshing
A new dry packaging operation can be required after an active inspection of inventory. Re-
freshing of the desiccant and moisture humidity indicator card should be controlled within a
small time interval taking care to limit moisture or other exposures. A refresh is necessary if
the desiccant used for storage is insufficient in quantity or if moisture has leaked into a rated
moisture barrier bag. Similarly, it shall be required to refresh with a new humidity indicator

card when the storage duration is beyond the demonstrated life or capability of the card to
detect moisture exposure.
4.8 Inventory re-assessment
Inventory re-assessment testing should be performed as required. It is not recommended to
perform full inventory re-assessment testing but rather targeted sampling of inventory to de-
termine remaining life or continued suitability for use.
5 Baseline long-term storage requirements
5.1 General
Storage of moisture sensitive components requires that all failure modes are mitigated and
that unit level traceability, supply chain of custody are in place and that critical aspects of the
storage environment are known and controlled. Further information about failure mechanisms
of interest and typical failure mitigation methods can be found in IEC 62435-2, IEC 62435-4,
IEC 61760-4 and JEDEC JEP-160. It is good practice to establish the storage time and envi-
ronment as when the technology is developed; prior to certification or qualification so that
added requirements can be integrated if required. Storage requirements beyond the basic
storage requirements in this document are the responsibility of the supplier or distributor as
agreed to in the terms and conditions of the purchasing contract.
5.2 Moisture sensitivity designation
Moisture sensitive devices shall be tested and rated according to IEC 60749-20, IEC 61760-4
and JEDEC JESD-020 prior to packing and storage. Packing shall be performed to ensure
that the board or system integration function is capable to utilize the declared floor life or re-
coverable floor life after baking. Package labelling shall identify moisture sensitivity parts and
the designated moisture sensitivity rating in accordance with IEC 60749-20-1 and JEDEC
JESD-020.
5.3 Dry packing for storage
If the device is rated as moisture sensitive, then dry packing with desiccant and a humidity
indicator card is required. The process for moisture barrier bag selection and determination of
desiccant quantity is outlined in the IEC 60749-20-1 or the JEDEC JESD-033.
5.4 Non-moisture sensitive storage
5.4.1 General
Parts that are not moisture sensitive should be packed and stored to reduce exposure to dust,
condensed moisture, chemical outgassing products and pollution residue. Mechanical integrity
and resistance to electrostatic discharge should also be maintained.
5.4.2 Storage media
Any storage media used for long-term storage should be free of surface contaminants or out-
gassing by-products that could act as stimuli for failure during final assembly.
5.4.3 Lot data and labelling
Data that indicates the product and traceability information should be stored with the units,
physically or electronically. Consideration should also be given to the storage of lot data
stored in paper or electronic device form. Paired lot information that is tied to the traceability
information should be stored using the data storage standards in IEC 62435-3 and
IEC 61760‑4.
– 14 – IEC 62435-8:2020 © IEC 2020
5.5 Storage of moisture sensitive finished devices
5.5.1 Moisture barrier bag
Moisture barrier bags used for long-term storage shall be rated for durability and the moisture
vapour transmission rate. The durability ensures a minimum level of handling capability. The
moisture vapour transmission rate that correlates to the leak rate is used to determine the
quantity of desiccant needed to absorb the moisture leaked into the bag over the duration of
the long-term storage.
5.5.2 Dunnage
Dunnage refers to all matter stored in a moisture barrier bag that is additional to the passive
electronic component. Examples of dunnage include: JEDEC trays, tape and reel, securing
straps and paper.
It is important to know the details of the dunnage moisture absorption prior to packing as well
as the occurrence of outgassing from the dunnage. Moisture that is absorbed into dunnage is
required to be considered in the calculations for amount of required desiccant.
Outgassing from dunnage should be considered because residues can contribute to next-level
assembly integration issues or corrosion and oxidation of exposed metal which results in long-
term reliability reduction.
The minimum and maximum rating for environmental exposure shall be known to ensure that
ambient storage excursions do not impact the ability of the media to protect the component
during and after storage. Accommodation should be made to avoid storage media degradation
(cracking, flaking or peeling) for the duration of storage. If components are stored in tape,
then the stored tape shall also be capable of being processed by the placement tool in a nor-
mal manner. It should be noted that some cover tapes and their adhesion may be compro-
mised in storage resulting in dropping of units when storage parts are removed from the tape
at final assembly.
5.5.3 Humidity indicator card
Humidity indicator cards in most cases should be packed in moisture barrier bags that contain
moisture sensitive electronics components. The validity of the humidity indicator card should
be assessed periodically.
5.5.4 Desiccant
The appropriate quantity of desiccant should be added to the moisture barrier bag to ensure
the customer or end-user receives the maximum declared time out of bag as indicated by the
moisture sensitivity level rating. The standards that should be used for desiccant charging are
IEC 60749-20-1 and JEDEC JESD-033. The preceding standards show the mathematical rela-
tionships for determination of the appropriate desiccant to be placed inside the moisture bar-
rier bag given a characteristic moisture vapour transmission rating, the maximum moisture
uptake for the dunnage and the moisture removal capability of the desiccant for the intended
storage duration.
5.5.5 Labelling
The lowest level of packing shall indicate the dry pack date and the lot traceability infor-
mation. The bag seal date indicates the beginning of the controlled storage period from which
the duration of storage can be determined. IEC 60749-20-1 IEC 61760-4 and JEDEC JESD-
020 provide the requirements for labelling.

5.5.6 Lot data and labelling
The data that indicates the product and traceability infor
...