EN IEC 62435-9:2021

Electronic components - Long-term storage of electronic semiconductor devices - Part 9: Special cases

IEC 62435-9:2021 specifies storage practices encompassing silicon and semiconductor device building blocks of all types that are integrated together to into products in the form of either packages or boards that can be stored as fully assembled units or partial assemblies. Special attention is given to memories as components and assemblies although methods also apply to heterogeneous components. Guidelines and requirements for customer-supplier interaction are provided to manage the complexity. NOTE In IEC 62435 (all parts), the term "components" is used interchangeably with dice, wafers, passives and packaged devices.

Elektronische Bauteile - Langzeitlagerung elektronischer Halbleiterbauteile – Teil 9: Sonderfälle

Composants électroniques - Stockage de longue durée des dispositifs électroniques à semiconducteurs - Partie 9: Cas particuliers

L’IEC 62435-9:2021 spécifie les pratiques de stockage de tous les types de blocs modules au silicium et à semiconducteurs, intégrés dans des produits sous la forme de boîtiers ou de cartes qui peuvent être stockés en unités intégralement assemblées ou en ensembles partiels. Les mémoires, qu’il s’agisse de composants ou d’ensembles, font l’objet d’une attention particulière, même si les méthodes s’appliquent également aux composants hétérogènes. Des lignes directrices et des exigences en matière d’interaction client/fournisseur sont données afin de gérer la complexité. NOTE Dans l’IEC 62435 (toutes les parties), le terme "composants" fait référence aux puces, aux plaquettes et aux dispositifs passifs et encapsulés.

Elektronske komponente - Dolgoročno skladiščenje elektronskih polprevodniških elementov - 9. del: Posebni primeri (IEC 62435-9:2021)

General Information

• Status: Published
• Publication Date: 30-Sep-2021
• ICS: 31.020 - Electronic components in general
• Technical Committee: CLC/TC 47X - Semiconductor devices and trusted chips
• Drafting Committee: IEC/TC 47 - IEC_TC_47
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 01-Oct-2021
• Completion Date: 01-Oct-2021
• Ref Project: SIST EN IEC 62435-9:2021 - Electronic components - Long-term storage of electronic semiconductor devices - Part 9: Special Cases (IEC 62435-9:2021)

Overview

EN IEC 62435-9:2021 (IEC 62435-9:2021) is part of the IEC 62435 series and specifies practices for the long-term storage of electronic semiconductor devices in special cases. It addresses silicon and semiconductor building blocks - dice, wafers, passives and packaged devices - stored as fully assembled units, partial assemblies, modules or boards. The standard defines long-term storage (LTS) as storage extending beyond 12 months and gives special attention to memory devices while covering heterogeneous and hybrid device configurations. It also includes guidelines to manage complexity through customer–supplier interaction.

Key topics and requirements

• Scope and definitions: Clarifies what constitutes LTS and which component configurations are covered (packages, assemblies, partial assemblies).
• Component storage cases: Describes different storage configurations and considerations for special-case assemblies.
• Storage of memory devices: Addresses memory-specific failure mechanisms and stimuli (see Table 1 of the document) and storage considerations for various memory types.
• Other devices and partial assemblies: Covers wafer-level chip-scale packages, heterogeneous devices and modules, including mixed-technology constraints.
• Alternative storage environments: Discusses non-standard environments and how the storage environment affects use reliability after retrieval.
• Customer–supplier interaction: Provides a template and requirements (Annex A) to ensure traceability, provenance, handling responsibilities and agreed storage processes.

Note: The standard avoids prescribing one-size-fits-all numerical storage conditions; instead it provides practical guidelines and interaction requirements so stakeholders can define appropriate LTS processes for their assemblies.

Practical applications and users

EN IEC 62435-9 is intended for organizations that must maintain electronic parts for extended service lives, including:

• Original equipment manufacturers (OEMs) in aerospace, railway, energy and industrial sectors
• Procurement and obsolescence managers executing lifetime buys
• Repair agencies and depot maintenance operations managing spare parts inventories
• Component and module suppliers who provide long-term storage services
• Quality, storage and reliability engineers defining storage qualification, traceability and retrieval procedures

Typical uses include planning preventive or remedial storage for obsolescent parts, defining contract terms for supplier-held spares, and minimizing degradation factors (moisture, contamination, UV, thermal cycling, ESD) through documented storage agreements.

Related standards

• IEC 62435 series (general LTS guidance)
• IEC TR 62258-3 (moisture-sensitive device storage - shorter-term focus)
• Harmonized references: IEC 60721 series, IEC 60050-192, IEC 60812 (see Annex ZA for normative links)

This standard helps organizations implement traceable, agreed storage practices to preserve component usability and manage obsolescence risk.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2021
Elektronske komponente - Dolgoročno skladiščenje elektronskih polprevodniških
elementov - 9. del: Posebni primeri (IEC 62435-9:2021)
Electronic components - Long-term storage of electronic semiconductor devices - Part 9:
Special Cases (IEC 62435-9:2021)
Elektronische Bauteile - Langzeitlagerung elektronischer Halbleiterbauteile – Teil 9:
Sonderfälle (IEC 62435-9:2021)
Composants électroniques - Stockage de longue durée des dispositifs électroniques à
semiconducteurs - Partie 9: Cas particuliers (IEC 62435-9:2021)
Ta slovenski standard je istoveten z: EN IEC 62435-9:2021
ICS:
31.080.01 Polprevodniški elementi Semiconductor devices in
(naprave) na splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 62435-9

NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2021
ICS 31.020
English Version
Electronic components - Long-term storage of electronic
semiconductor devices - Part 9: Special cases
(IEC 62435-9:2021)
Composants électroniques - Stockage de longue durée des Elektronische Bauteile - Langzeitlagerung elektronischer
dispositifs électroniques à semiconducteurs - Partie 9: Cas Halbleiterbauteile - Teil 9: Sonderfälle
particuliers (IEC 62435-9:2021)
(IEC 62435-9:2021)
This European Standard was approved by CENELEC on 2021-09-29. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 62435-9:2021 E

European foreword
The text of document 47/2700/FDIS, future edition 1 of IEC 62435-9, prepared by IEC/TC 47
"Semiconductor devices" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 62435-9:2021.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2022-06-29
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2024-09-29
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 62435-9:2021 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
IEC 60721 series NOTE Harmonized as EN 60721 series
IEC 60721-3-1 NOTE Harmonized as EN IEC 60721-3-1
IEC 60812 NOTE Harmonized as EN IEC 60812
IEC 62435 series NOTE Harmonized as EN IEC 62435 series
IEC 62435-1 NOTE Harmonized as EN 62435-1
IEC 62435-3 NOTE Harmonized as EN IEC 62435-3
IEC 62435-6 NOTE Harmonized as EN IEC 62435-6
IEC 62435-7 NOTE Harmonized as EN IEC 62435-7

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-192 -  International electrotechnical vocabulary - - -
Part 192: Dependability
IEC 62435-9 ®
Edition 1.0 2021-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electronic components – Long-term storage of electronic semiconductor

devices –
Part 9: Special cases
Composants électroniques – Stockage de longue durée des dispositifs

électroniques à semiconducteurs –

Partie 9: Cas particuliers
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.020 ISBN 978-2-8322-1016-3

– 2 – IEC 62435-9:2021 © IEC 2021
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Component storage cases . 9
5 Storage of memory devices . 9
5.1 General . 9
5.2 Semiconductor memory device types . 9
6 Storage of other devices and partial assembly . 11
6.1 General . 11
6.2 Wafer-level chip-scale packages . 11
6.3 Heterogeneous devices. 12
6.4 Modules . 12
7 Storage in alternative environments . 12
7.1 General . 12
7.2 Alternative environments . 12
7.3 Storage environment effect on use reliability . 13
Annex A (informative)  Customer-supplier interaction . 14
Bibliography . 15

Table 1 – Example failure mechanisms and stimuli for memory devices . 10
Table A.1 – Supplier – customer interaction template. 14

IEC 62435-9:2021 © IEC 2021 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC COMPONENTS – LONG-TERM STORAGE
OF ELECTRONIC SEMICONDUCTOR DEVICES –

Part 9: Special cases
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
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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.
IEC 62435-9 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
47/2700/FDIS 47/2716/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.

– 4 – IEC 62435-9:2021 © IEC 2021
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.
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 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.
IEC 62435-9:2021 © IEC 2021 – 5 –
INTRODUCTION
This document applies to the long-term storage of electronic components in special cases of
configuration. The custom-client relationship for storage of all cases is also included.
This document deals with the 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
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 its 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, ultra-violet light, large variations in temperature, air-borne contaminants, and outgassing.
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.
The storage of devices that are moisture sensitive but that do not need to be stored for long
periods of time is dealt with in IEC TR 62258-3.

– 6 – IEC 62435-9:2021 © IEC 2021
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 be useable after storage. It is important that storage
media, the local environment and the associated part data be considered together.
Local environments for long term storage can be unique to the application or to the type of
subassembly being stored for further assembly. Different device types that are integrated into
a single package or module can have different storage requirements that should be considered
during long term storage. A product can contain a single die or multiple dice (example: a CMOS
processor, a GaN radio, sensors and a new type of memory). Each device technology can
impose storage requirements. For example: the memory can be removed from x-ray or high
magnetic field sources and the sensors can be stored in a dark environment or low-pressure
environment.
Such practice requires good communication interactions and agreements for storage that
should account for the possibility and complexity of intermediate assembly of heterogeneous
devices. Successful customer supplier interaction involves clear expectations for device
provenance, traceability and identification.
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 IEC 62435 (all parts).
The overall standard 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.
The structure of the IEC 62435 series consists of the following:
– 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
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