Electronic components - Long-term storage of electronic semiconductor devices - Part 6: Packaged or finished devices

IEC 62435-6:2018 on long-term storage applies to packaged or finished devices 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. Philosophy, good working practice, and general means to facilitate the successful long-term storage of electronic components are also addressed.

Composants électroniques - Stockage de longue durée des dispositifs électroniques à semiconducteurs - Partie 6: Dispositifs encapsulés ou finis

L’IEC 62435-6:2018 portant sur le stockage de longue durée s’applique aux dispositifs encapsulés ou finis en stockage de longue durée qui peuvent être utilisés dans le cadre d’une stratégie de réduction de l’obsolescence. Le stockage de longue durée fait référence à une durée qui peut être supérieure à 12 mois, pour un produit destiné à être stocké. Les concepts, les bonnes pratiques et les moyens généraux de nature à faciliter la réussite d’un stockage de longue durée de composants électroniques sont aussi abordés.

General Information

Status
Published
Publication Date
28-Aug-2018
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
29-Aug-2018
Ref Project

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IEC 62435-6
Edition 1.0 2018-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electronic components – Long-term storage of electronic semiconductor
devices –
Part 6: Packaged or finished devices
Composants électroniques – Stockage de longue durée des dispositifs
électroniques à semiconducteurs –
Partie 6: Dispositifs encapsulés ou finis
IEC 62435-6:2018-08(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 62435-6
Edition 1.0 2018-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electronic components – Long-term storage of electronic semiconductor
devices –
Part 6: Packaged or finished devices
Composants électroniques – Stockage de longue durée des dispositifs
électroniques à semiconducteurs –
Partie 6: Dispositifs encapsulés ou finis
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.020 ISBN 978-2-8322-5979-5

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 62435-6:2018 © IEC 2018
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ..................................................................................................................... 5

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Storage considerations .................................................................................................... 9

4.1 Failure mechanisms ................................................................................................ 9

4.1.1 Occurrence of failure and driving force ............................................................ 9

4.1.2 Storage environment and mitigation for stimuli to prevent failure ................... 10

4.2 Materials management .......................................................................................... 11

4.3 Storage media ...................................................................................................... 11

4.4 Inventory check..................................................................................................... 11

4.5 Inventory dry packing refreshing ........................................................................... 12

4.6 Inventory re-assessment ....................................................................................... 12

5 Baseline long-term storage requirements ....................................................................... 12

5.1 General ................................................................................................................. 12

5.1.1 Categories ..................................................................................................... 12

5.1.2 Critical aspects .............................................................................................. 12

5.1.3 Recommendations and best practice ............................................................. 12

5.2 Non-moisture sensitive device storage .................................................................. 13

5.2.1 Storage media ............................................................................................... 13

5.2.2 Lot data and labelling .................................................................................... 13

5.3 Moisture sensitive finished device storage ............................................................ 13

5.3.1 Moisture sensitivity designation ..................................................................... 13

5.3.2 Dry packing for storage .................................................................................. 13

5.3.3 Moisture barrier bag ...................................................................................... 13

5.3.4 Dunnage ........................................................................................................ 13

5.3.5 Humidity indicator card – HIC ........................................................................ 14

5.3.6 Desiccant ...................................................................................................... 14

5.3.7 Labelling ........................................................................................................ 14

5.4 Storage environment ............................................................................................. 14

5.5 Process (temperature) sensitivity designation ....................................................... 14

Annex A (informative) Packaged or finished device storage environment

considerations ...................................................................................................................... 15

Bibliography .......................................................................................................................... 16

Table 1 – Example failure mechanisms in storage and stimuli to mitigate during storage ........ 9

Table 2 – Long-term environment – Sustained condition requirements .................................. 10

Table 3 – Considerations for management, control and documentation during storage .......... 11

Table A.1 – Long-term storage environment – Sustained condition considerations ................ 15

---------------------- Page: 4 ----------------------
IEC 62435-6:2018 © IEC 2018 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC COMPONENTS – LONG-TERM STORAGE OF
ELECTRONIC SEMICONDUCTOR DEVICES –
Part 6: Packaged or finished devices
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote interna-

tional co-operation on all questions concerning standardization in the electrical and electronic fields. To this

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nical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publica-

tion(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the

subject dealt with may participate in this preparatory work. International, governmental and non-governmental

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tional Organization for Standardization (ISO) in accordance with conditions determined by agreement between

the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all inter-

ested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

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6) All users should ensure that they have the latest edition of this publication.

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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 62435-6 has been prepared by IEC technical committee 47: Semi-

conductor devices.
The text of this International Standard is based on the following documents:
FDIS Report on voting
47/2482/FDIS 47/2495/RVD

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.

---------------------- Page: 5 ----------------------
– 4 – IEC 62435-6:2018 © IEC 2018

A list of all parts in the IEC 62435 series, published under the general title Electronic compo-

nents – 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.
---------------------- Page: 6 ----------------------
IEC 62435-6:2018 © IEC 2018 – 5 –
INTRODUCTION
This document applies to the long-term storage of 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 standard, 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 component manufacturer for the lifetime of the system or the spare as-

sembly can be built with the original production run but then requires long-term storage. This

document was developed to provide a standard for storing electronic devices for long periods

---------------------- Page: 7 ----------------------
– 6 – IEC 62435-6:2018 © IEC 2018

of time. For storage 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 original component 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 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
---------------------- Page: 8 ----------------------
IEC 62435-6:2018 © IEC 2018 – 7 –
ELECTRONIC COMPONENTS – LONG-TERM STORAGE OF
ELECTRONIC SEMICONDUCTOR DEVICES –
Part 6: Packaged or finished devices
1 Scope

This part of IEC 62435 on long-term storage applies to packaged or finished devices 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. Phi-

losophy, good working practice, and general means to facilitate the successful long-term stor-

age 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

JEDEC J-STD-020, Moisture/reflow classification for nonhermetic solid state surface mount

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
storage environment

specially controlled storage area, with particular control of temperature, humidity, atmosphere

and any other conditions depending on the product requirements
3.2
critical moisture limit

maximum safe equilibrium moisture content for a specific encapsulated device at reflow as-

sembly or rework
---------------------- Page: 9 ----------------------
– 8 – IEC 62435-6:2018 © IEC 2018
3.3
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 (for example; packing materials, shape) and

storage conditions. In general, long-term storage is longer than 12 months.
3.4
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
3.5
moisture-sensitive device
MSD

device that has moisture absorption or moisture retention and whose quality or reliability is

affected by moisture
3.6
electronic device

packaged electrical, electronic, electro-mechanical (EEE) item, or assemblies using such

items
3.7
desiccant
hygroscopic substance used to remove moisture from an atmosphere
3.8
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.

3.9
humidity indicator card
HIC

card printed with a moisture sensitive chemical that changes, typically, from blue to pink in

the presence of water vapour
3.10
water vapour transmission rate
WVTR
measure of permeability of MBBs to water vapour
3.11
dunnage

all the matter stored in a moisture barrier bag that is additional to the packaged electronic

component
3.12
electrostatic discharge
ESD

transfer of electric charge between bodies of different electrostatic potentials in proximity or

through direct contact
---------------------- Page: 10 ----------------------
IEC 62435-6:2018 © IEC 2018 – 9 –
[SOURCE: IEC 60050-561:2014, 561-03-06]
4 Storage considerations
4.1 Failure mechanisms
4.1.1 Occurrence of failure and driving force

Failures during long-term storage may be mitigated by control of the stimuli and driving forces

likely to initiate 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, vis-

ual quality or other non-conformance. The modes of failure during storage are typically related

to a failure mechanism 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 fail-

ure modes and effect analysis based on information from technology development and test-

ing. Table 1 provides examples of failure stimuli. Additional examples of deterioration mecha-

nisms 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 – Example failure mechanisms in storage and stimuli to mitigate during storage

Failure Failure mechanism detail Failure mode Mechanism stimuli
mechanism

Popcorn High rate vapour expansion Open circuit, blistering, Temperature increase leading to

effect within a package during sur- package cracks moisture vapour
face mounting
Handling Cracking Open, short, visible crack Application of force
damage
Visible scratch/smudge Open, short, surface mark Mechanical abrasion

Device data Electro-magnetic current Open, short, data corrup- Electro-magnetic field

loss/damage field induced tion
short/open/error

High ionizing radiation in- Open, short, data corrup- High-energy radiation, x-ray

duced open, short or error tion
Soft error resulting from Open, short or data cor- Neutron particle hit
device damage ruption
Alpha particle emission hit

Staining Change in surface appear- Visible defect, non- Exposure resulting in aging, oxida-

residue ance and specification re- conforming appearance tion or hardening of residue

sulting from unplanned ex- and potential of mispro-
posure to oxidizing contents cessing

Polymer Polymer embrittlement Visible cracking, open or Temperature exposure, residual

material shorting mechanical stress and bright light
aging

Storage Tape on reel, tube embrit- Misalignment during pro- Temperature exposure, mechanical

media tlement/aging cessing stressing and bright light
issues

Tray and tube aging embrit- Dropped parts from broken Temperature, handling and bright

tlement tray media or parts out of light
formed pocket
Dropped parts
Box aging embrittlement Temperature and bright light
Opens or shorts from ESD
Foreign material

ESD coating degradations Opens or shorts from ESD Triboelectric charging or charge

potential difference
Label aging Illegible mark Bright light, temperature
Missing label Temperature and bright light
Brittle flaking – partial Temperature and bright light
label
---------------------- Page: 11 ----------------------
– 10 – IEC 62435-6:2018 © IEC 2018
Failure Failure mechanism detail Failure mode Mechanism stimuli
mechanism

Indirect Moisture barrier bag leak Humidity indicator card Handling abrasion, bending and

material trigger, visual non- shock events
issues conformance

Humidity Indicator Card In- Incorrect colour or no Temperature, humidity Exposure

activated moisture exposure indicat- before use
Label aging Illegible mark Bright light, temperature
Missing label Temperature and bright light
Brittle flaking – partial Temperature and bright light
label

Solderability Inability to form a good sol- Post surface mount elec- Temperature, humidity Exposure

der joint trical open
Corrosion Electro-chemical reaction
...

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