Electronic components - Long-term storage of electronic semiconductor devices - Part 7: Micro-electromechanical devices

IEC 62435-7:2020 on long-term storage applies to micro-electromechanical devices (MEMS) in long-term storage that can be used as part of obsolescence mitigation strategy. Long-term storage refers to a duration that may be more than 12 months for products 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 7: Dispositifs microélectromécaniques

L'IEC 62435-7:2020 relative au stockage de longue durée s’applique aux dispositifs microélectromécaniques (MEMS - micro-electromechanical device) du stockage de longue durée qui peuvent être utilisés dans le cadre d’une stratégie de réduction de l’obsolescence. Le stockage de longue durée implique une durée qui peut être supérieure à 12 mois, pour les produits destinés à être stockés. Les concepts, les bonnes pratiques professionnelles et les moyens généraux de nature à faciliter un stockage optimum de longue durée de composants électroniques sont aussi traités.

General Information

Status
Published
Publication Date
03-Dec-2020
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
04-Dec-2020
Ref Project

Buy Standard

Standard
IEC 62435-7:2020 - Electronic components - Long-term storage of electronic semiconductor devices - Part 7: Micro-electromechanical devices
English and French language
39 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

IEC 62435-7
Edition 1.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electronic components – Long-term storage of electronic semiconductor
devices –
Part 7: Micro-electromechanical devices
Composants électroniques – Stockage de longue durée des dispositifs
électroniques à semiconducteurs –
Partie 7: Dispositifs microélectromécaniques
IEC 62435-7:2020-12(en-fr)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2020 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form

or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from

either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC

copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or

your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite

ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie

et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des

questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez

les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC

The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes

International Standards for all electrical, electronic and related technologies.
About IEC publications

The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the

latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org

The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,

variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English

committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.

and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary

details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and

once a month by email. French extracted from the Terms and Definitions clause of

IEC publications issued since 2002. Some entries have been

IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and

If you wish to give us your feedback on this publication or CISPR.
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC

La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des

Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC

Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la

plus récente, un corrigendum ou amendement peut avoir été publié.
Recherche de publications IEC - Electropedia - www.electropedia.org

webstore.iec.ch/advsearchform Le premier dictionnaire d'électrotechnologie en ligne au

La recherche avancée permet de trouver des publications IEC monde, avec plus de 22 000 articles terminologiques en

en utilisant différents critères (numéro de référence, texte, anglais et en français, ainsi que les termes équivalents dans

comité d’études,…). Elle donne aussi des informations sur les 16 langues additionnelles. Egalement appelé Vocabulaire

projets et les publications remplacées ou retirées. Electrotechnique International (IEV) en ligne.

IEC Just Published - webstore.iec.ch/justpublished Glossaire IEC - std.iec.ch/glossary

Restez informé sur les nouvelles publications IEC. Just 67 000 entrées terminologiques électrotechniques, en anglais

Published détaille les nouvelles publications parues. et en français, extraites des articles Termes et Définitions des

Disponible en ligne et une fois par mois par email. publications IEC parues depuis 2002. Plus certaines entrées

antérieures extraites des publications des CE 37, 77, 86 et
Service Clients - webstore.iec.ch/csc CISPR de l'IEC.
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
---------------------- Page: 2 ----------------------
IEC 62435-7
Edition 1.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electronic components – Long-term storage of electronic semiconductor
devices –
Part 7: Micro-electromechanical devices
Composants électroniques – Stockage de longue durée des dispositifs
électroniques à semiconducteurs –
Partie 7: Dispositifs microélectromécaniques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.020 ISBN 978-2-8322-9147-4

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 62435-7:2020 © 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 MEMS applications .............................................................................. 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 ................... 12

4.3 Materials management .......................................................................................... 13

4.4 Storage media ...................................................................................................... 13

4.5 Documentation/paper lot identifiers ....................................................................... 14

4.6 Inventory check..................................................................................................... 14

4.7 Inventory dry packing refreshing ........................................................................... 14

4.8 Inventory re-assessment ....................................................................................... 14

5 Baseline long-term storage requirements ....................................................................... 14

5.1 General ................................................................................................................. 14

5.2 Moisture sensitivity designation ............................................................................ 15

5.3 Dry packing for storage ......................................................................................... 15

5.4 Non-moisture sensitive device storage .................................................................. 15

5.4.1 General ......................................................................................................... 15

5.4.2 Storage media ............................................................................................... 15

5.4.3 Lot data and labelling .................................................................................... 15

5.5 Storage of MEMS devices before assembly – Wafer level and die level

storage ................................................................................................................. 15

5.6 Storage of moisture sensitive finished devices ...................................................... 15

5.6.1 Moisture barrier bag ...................................................................................... 15

5.6.2 Dunnage ........................................................................................................ 16

5.6.3 Humidity indicator card .................................................................................. 16

5.6.4 Desiccant ...................................................................................................... 16

5.6.5 Labelling ........................................................................................................ 16

5.6.6 Lot data and labelling .................................................................................... 16

5.6.7 Storage environment ..................................................................................... 17

5.6.8 Process (temperature) sensitivity designation ................................................ 17

Annex A (informative) Packaged or finished device storage environment

considerations ...................................................................................................................... 18

Bibliography .......................................................................................................................... 19

Table 1 – Failure mechanisms in storage and stimuli to mitigate during storage .................... 10

Table 2 – Long-term environment – sustained condition requirements .................................. 13

Table 3 – Considerations for management, control and documentation during storage .......... 13

Table A.1 – Long-term storage environment – sustained condition considerations ................ 18

---------------------- Page: 4 ----------------------
IEC 62435-7:2020 © IEC 2020 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC COMPONENTS – LONG-TERM STORAGE
OF ELECTRONIC SEMICONDUCTOR DEVICES –
Part 7: Micro-electromechanical 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 international

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

in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,

Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their prepa-

ration 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 organizations liaising with

the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Stand-

ardization (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

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinter-

pretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications trans-

parently to the maximum extent possible in their national and regional publications. Any divergence between any

IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

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

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and ex-

penses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.

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.

IEC 62435-7 has been prepared by IEC technical committee 47: Semiconductor devices. It is

an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
47/2664/FDIS 47/2669/RVD

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are

described in greater detail at www.iec.ch/standardsdev/publications.
---------------------- Page: 5 ----------------------
– 4 – IEC 62435-7:2020 © IEC 2020

A list of all 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.
---------------------- Page: 6 ----------------------
IEC 62435-7:2020 © IEC 2020 – 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 document, LTS is defined as

any device storage whose duration may 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

aeronautical field, the railway industry or the energy sector.

The many solutions enabling obsolescence to be resolved are now identified. However,

selecting 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

decades, 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

according 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 comprises 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 their individual parts. This puts the user in a situation requiring

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 contaminants, and

outgassing.
---------------------- Page: 7 ----------------------
– 6 – IEC 62435-7:2020 © IEC 2020

Warranties and sparing also present a challenge for the user or repair agency as some systems

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 available 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 developed to

provide a standard for storing electronic devices for long periods of time. For storage of devices

that are moisture sensitive but that do not need to be stored for long periods of time, refer to

IEC TR 62258-3.

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 suppliers

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 series is split into a number of parts. Parts 1 to 4 apply to any long-term

storage 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 Part 1 to 4.

Electronic components requiring different storage conditions are covered separately 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 – Micro-electromechanical devices – MEMS
Part 8 – Passive electronic devices
Part 9 – Special cases
---------------------- Page: 8 ----------------------
IEC 62435-7:2020 © IEC 2020 – 7 –
ELECTRONIC COMPONENTS – LONG-TERM STORAGE
OF ELECTRONIC SEMICONDUCTOR DEVICES –
Part 7: Micro-electromechanical devices
1 Scope

This part of IEC 62435 on long-term storage applies to micro-electromechanical devices (MEMS)

in long-term storage that can be used as part of obsolescence mitigation strategy. Long-term

storage refers to a duration that may be more than 12 months for products scheduled for storage.

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 content

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 60721-3-1, Classification of environmental conditions – Part 3-1: Classification of groups

of environmental parameters and their severities – Storage

IEC 60749-20, Semiconductor devices – Mechanical and climatic test methods – Part 20:

Resistance 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 62435-2, Electronic components – Long-term storage of electronic semiconductor devices

– Part 2: Deterioration mechanisms

IEC 62435-3, Electronic components – Long-term storage of electronic semiconductor devices

– Part 3: Data

IEC 62435-4, Electronic components – Long-term storage of electronic semiconductor devices

– Part 4: Storage

IEC 62435-5, Electronic components – Long-term storage of electronic semiconductor devices

– Part 5: Die and wafer devices
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

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
---------------------- Page: 9 ----------------------
– 8 – IEC 62435-7:2020 © IEC 2020
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 assem-

bly or rework
3.3
long-term storage
LTS

planned storage of components to extend the life-cycle for a duration with the intention of sup-

porting future use

Note 1 to entry: Allowable storage durations will vary by product, form factor (e.g., 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 moisture

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, process ability 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 trans-

mission 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 from blue to pink (colour) in the

presence of water vapour
3.10
water vapour transmission rate
WVTR
measure of permeability of MBBs to water vapour
---------------------- Page: 10 ----------------------
IEC 62435-7:2020 © IEC 2020 – 9 –
3.11
dunnage

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

component
3.12
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 MEMS applications

MEMS (Micro-electromechanical Systems) are miniaturized mechanical or electromechanical

elements that typically vary in size from 1 micron to 1 000 microns that are used to mechanically

measure or manipulate matter, light or create electric signals from environmental inputs.

Storage of MEMS devices should consider different sensitivities and risks compared to other

semiconductor devices due to the mechanical nature of the devices. MEMS may be subject to

additional mechanical related performance and failure mechanisms in addition traditional

semiconductor performance mechanisms. The storage program should consider the end use

and failure mechanisms related to the function of the MEMS device. Typical uses are listed for

initial consideration and risk assessment.

– Actuator mechanical movement related to electrostatics, thermal changes or piezoelectric

effects.

– Physical sensors related to acceleration, vibration, field/flux, force, magnetic field, electro-

static, optical stimulus or radiation effects, pressure, temperature.

– Chemisensors related to gas or liquid induced mechanical response changes (may also

have requirements for moisture or solvent which also have shelf life).

– Biosensors liquid, mechanical or fluidic induced mechanical response changes (may also

have requirements for moisture or solvent which also have shelf life).
4.2 Failure mechanisms
4.2.1 Occurrence of failure and driving force

Failures during long-term storage may be mitigated by control of the stimuli driving given failure

modes of interest as defined by risk assessment tools, for example, failure modes and effects

analysis (FMEA). Storage related failures are often detected as modes of non-operation, visual

quality, reduced life time 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. 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.
---------------------- Page: 11 ----------------------
– 10 – IEC 62435-7:2020 © IEC 2020
Table 1 – Failure mechanisms in storage and stimuli to mitigate during storage
Failure Failure mechanism Failure mode Mechanism stimuli
mechanism detail
Popcorn High rate vapour Open circuit, Temperature increase leading to moisture
effect expansion within a blistering, package vapour
package during cracks
surface mounting
Handling Cracking Open, short, visible Application of force
damage crack, sense signal
degradation
Visible Open, short, surface
Mechanical abrasion
scratch/smudge mark, sense signal
degradation
Physical crack in Open, short, sense
Excessive pressure change
sensing device signal degradation
Mechanical Sensitivity shift, non- Sources of mechanical overstress are shock,

overstress parametric sensitivity, fatigue, vibration, corrosion or the effects of

offset shift, stuck at electrical overstress (EOS) or electrostatic
discharge (ESD) that result in structural
damag
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.