1、DRAFT FOR DEVELOPMENTDD CLC/TS 50466:2006Long duration storage of electronic components Specification for implementationICS 31.020g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g5
2、1g60g53g44g42g43g55g3g47g36g58DD CLC/TS 50466:2006This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 30 June 2008 BSI 2008ISBN 978 0 580 59096 2National forewordThis Draft for Development is the UK implementation of CLC/TS 50466:2006. This
3、publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publications and is of a provisional nature. It should be applied on this provisional basis, so that information and experience of its practical application can be obtained.Comments aris
4、ing from the use of this Draft for Development are requested so that UK experience can be reported to the European organization responsible for its conversion to a European standard. A review of this publication will be initiated not later than three years after its publication by the European organ
5、ization so that a decision can be taken on its status. Notification of the start of the review period will be made in an announcement in the appropriate issue of Update Standards.According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to s
6、upport the conversion into a European Standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent to the Secretary of the responsible BSI Technical Committee at British Standards House, 389 Chiswick High Road, London W4 4AL.The UK participation in its prepa
7、ration was entrusted to Technical Committee GEL/107, Process management for avionics.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for it
8、s correct application.Amendments/corrigenda issued since publicationDate CommentsTECHNICAL SPECIFICATION CLC/TS 50466 SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATION May 2006 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches K
9、omitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. CLC/TS 50466:2006 E ICS 31.020 English version Long duration storage of electronic co
10、mponents Specification for implementation Stockage longue dure des composants lectroniques Guide de mise en oeuvre Langzeitlagerung von elektronischen Bauelementen Spezifikation fr die Ausfhrung This Technical Specification was approved by CENELEC on 2005-12-03. CENELEC members are required to annou
11、nce the existence of this TS in the same way as for an EN and to make the TS available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the C
12、zech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Foreword This Technical Specification
13、was prepared by the Technical Committee CENELEC TC 107X, Process management for avionics. The text of the draft was submitted to the formal vote and was approved by CENELEC as CLC/TS 50466 on 2005-12-03. The following date was fixed: latest date by which the existence of the CLC/TS has to be announc
14、ed at national level (doa) 2006-06-03 This document, which is in line with IEC/PAS 62435 relating to the management of obsolescence of electronic components, is first of all a practical guide to methods of long duration storage (more than 5 years) which summarizes the existing practices in the indus
15、try. The application of the approach proposed in this guide 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. Unless otherwise specified, the approach, as
16、well as the methods presented apply to all families of electronic components: passive components, including quartz crystals, connectors and relays. However, components with “manufacturers“ specifications showing an expiry date, or specific storage conditions, are excluded from this guide (e.g. prima
17、ry cells, storage cells, etc.), encapsulated or non-encapsulated active components of a silicon Si or gallium arsenide GaAs technology, micro-electronic assemblies. 2 CLC/TS 50466:2006Contents 1 General 5 2 Normative references5 3 Storage decision criteria 6 3.1 Advantages of storage .6 3.1.1 Techni
18、cal simplicity Rapidity.6 3.1.2 Solution durability 6 3.1.3 Preventive storage.6 3.2 Hazards Drawbacks6 3.2.1 Generic aging hazard.6 3.2.2 Poor stock dimensioning.7 3.2.3 Incorrect control of reliability during storage 7 3.2.4 Freezing equipment functionalities.7 3.3 Storage cost (Annex C) 7 3.4 Dec
19、ision criteria.7 4 Purchasing procurement8 4.1 List of components 8 4.2 Quantity of components to be stored8 4.2.1 Production stock8 4.2.2 Field service stock .8 4.3 When is it worth keeping in stock?.9 4.4 Procurement recommendations.9 5 Technical validation of the components 9 5.1 Purpose .9 5.2 R
20、elevant field9 5.3 Test selection criteria .10 5.4 Measurements and tests 10 5.4.1 Sampling 10 5.4.2 Visual examination, sealing, solderability11 5.4.3 Compliance with the electrical specifications.11 5.4.3.1 Measurement of electrical parameters .11 5.4.3.2 Temperature impact 12 5.4.4 Assessment of
21、the supplied batch reliability 12 5.4.5 Manufacturing control check (technological analysis) .14 5.5 Sanction.14 6 Conditioning and storage.14 6.1 Type of environment 14 6.2 Elementary storage unit .15 6.3 Stock management15 6.4 Redundancy .15 6.5 Identification - Traceability 15 6.6 Initial packagi
22、ng 15 6.7 Solderability16 6.8 Stabilization bake 16 6.9 Storage conditions.16 6.9.1 Storage area.16 6.9.2 Temperature .16 6.9.3 Temperature variations.16 6.9.4 Relative humidity - Chemical attacks - Contamination 16 6.9.5 Pressure.17 6.9.6 Electrostatic discharges17 3 CLC/TS 50466:20066.9.7 Vibratio
23、ns Mechanical impacts17 6.9.8 Electromagnetic field - Radiation .17 6.9.9 Light.17 6.10 Maintaining storage conditions17 7 Periodic check of the components 18 7.1 Objectives 18 7.2 Periodicity.18 7.3 Tests during periodic check 18 8 De-stocking18 8.1 Precautions 18 8.1.1 Electrostatic discharges19 8
24、.1.2 Mechanical impacts .19 8.2 Inspection.19 9 Feedfback .19 Annex A Example related to components 20 A.1 Example of a component list .20 A.2 Data description21 Annex B Examples of periodic and/or destocking tests22 Annex C Parameters influencing the final price of the component storage24 Annex D P
25、arameters influencing the quantity of the components to be stored.25 Annex E Failure mechanisms - Hermetically encapsulated and non-encapsulated active components.26 Annex F Failure mechanisms: GaAs components28 Bibliography . 30 Table E.1 Failure mechanisms - Hermetically encapsulated and non-encap
26、sulated active components .26 Table F.1 Failure modes compared with initial table on the silicon devices.28 Table F.2 Failure modes specific to GaAs components 29 4 CLC/TS 50466:20061 General Although it has always existed to some extent, obsolescence of electronic components, and particularly integ
27、rated 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 those encountered in the aeronautical field, the railway industry or
28、the energy sector. The many solutions enabling obsolescence to be resolved are now identified. However, selecting one of these solutions must be preceded by a case by case technical and economic feasibility study, depending on whether storage is envisaged for field service or production. Remedial st
29、orage 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 so
30、lution to be adopted to resolve obsolescence must 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
31、requires the 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 should be performed in accordance with the technology requirements of t
32、he component. 2 Normative references The following referenced documents are indispensable for the application 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. EN 190000:19
33、95, Generic specification: Integrated monolithic circuits EN 60068-2-17:1994, Environmental testing - Part 2: Tests - Test Q: Sealing (IEC 60068-2-17:1994) HD 323.2.20 S3:1988, Basic environmental testing procedures - Part 2: Tests - Test T: Soldering (IEC 60068-2-20:1979 + A2:1987) IEC 60410:1973,
34、Sampling plans and procedures for inspection by attributes 5 CLC/TS 50466:20063 Storage decision criteria Before taking the decision to store electronic components the following should be reviewed. On the one hand, after having compared with the following additional solutions: modification to the pr
35、inted board by adding a “backpack“ macro-component, development of a specific ASIC, production re-launched at a manufacturer specialized in the resumption of obsolete technological processes and components, complete revision of the board or the equipment. On the other hand, by taking into account th
36、e following aspects: 3.1 Advantages of storage 3.1.1 Technical simplicity Rapidity When the various steps of the storage process are finalized and validated, the creation of a stock is a simpler, faster and technically less hazardous solution than developing or modifying electronic boards. Storage c
37、an also be a temporary solution enabling equipment maintenance and production continuity during modification or development of superseding electronic boards. 3.1.2 Solution durability Any equipment changes based on the use of new electronic components will be faced, eventually, with the obsolescence
38、 of these new components. Storage can resolve obsolescence problems until the end of the operating life of the equipment. 3.1.3 Preventive storage Preventive storage (i.e. before the component becomes obsolete) presents several additional advantages compared with remedial storage (i.e. when the comp
39、onent has already become obsolete): the component price has not become prohibitive as in the case of specific obsolete components which have become very rare; the quality level is ensured if the component can be directly purchased from the manufacturers or at approved distributors. When a component
40、has been obsolete for a long time, it can only be found at specialists in purchasing, storage and resale of obsolete components (“brokers“). In this case, no component reliability guarantee will apply. These components must have traceability back to the original manufacturer. 3.2 Hazards Drawbacks 3
41、.2.1 Generic aging hazard Stock dimensioning is based on the assumption of a constant component failure rate. The problem of generic aging of the components (“bath tub curve“) cannot be easily taken into account and quantified. However, the current electronic components seem to have extremely long l
42、ives provided that they have been manufactured with their quality assurance guaranteed, and that they are used in accordance with their specifications. 6 CLC/TS 50466:20063.2.2 Poor stock dimensioning The calculation of the number of components to be stored may be based on feedback (opera-tional fai
43、lure rate) and/or on theoretical models (predictive failure rate). Calculation using feed-back is only valid if the sample is big enough (significant population of components installed, operation for several years, high number of failures evidenced). Predictive calculations do not generally take int
44、o account the extrinsic parameters of the components (defects caused by printed board handling and repair, systematic replacement of the components (including functional components) during repairs, improper use of the components, etc.). Therefore the stock volume may be improperly assessed. Underest
45、imating the stock may lead to a lack of components to repair printed boards, which will ruin the stock strategy. Overestimating it will lead to the purchasing and conditioning of compo-nents which will not be used, including to significant additional costs. 3.2.3 Incorrect control of reliability dur
46、ing storage Storage conditions must be precisely defined and controlled, in order to guarantee the reliability of the components stored (refer to Clause 5). In addition, it is important to check the quality of the components to be stored (refer to Clause 4). This may lead to the setting up of fairly
47、 heavy and costly infrastructure and procedures. Checking component quality may be an efficient means of reducing the risk of improper reliability control during storage. This can be done either by performing periodic sampling in order to carry out tests on the components (refer to Clause 6) or by c
48、hecking that the components taken from the stock and used on the electronic boards operate correctly (provided that the consumption of the components in stock is sufficiently regular). 3.2.4 Freezing equipment functionalities Storing components to ensure equipment maintenance over a long time implie
49、s that the equipment functionalities be frozen. A long-duration storage solution is therefore not very compatible with the wish to upgrade equipment and functionalities. 3.3 Storage cost (Annex C) In order to assess the cost of a storage solution, various items should be taken into account, such as: component purchasing; validation / test of purchased component batches; conditioning and deconditioning; test equipment for periodic sampling will have to be maintained; stock management; m
