1、BRITISH STANDARDBS EN 60068-2-82: 2007Environmental testing Part 2-82: Tests Test Tx: Whisker test methods for electronic and electric componentsThe European Standard EN 60068-2-82:2007 has the status of a British StandardICS 19.040; 31.190g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54
2、g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 60068-2-82:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2007 BSI 2007ISBN 978 0 5
3、80 55334 9National forewordThis British Standard is the UK implementation of EN 60068-2-82:2007. It is identical to IEC 60068-2-82:2007.The UK participation in its preparation was entrusted to Technical Committee EPL/501, Electronic assembly technology.A list of organizations represented on this com
4、mittee 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 its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publi
5、cationAmd. No. Date CommentsEUROPEAN STANDARD EN 60068-2-82 NORME EUROPENNE EUROPISCHE NORM June 2007 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart
6、35, B - 1050 Brussels 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60068-2-82:2007 E ICS 19.040; 31.190 English version Environmental testing - Part 2-82: Tests - Test Tx: Whisker test methods for electronic and electric c
7、omponents (IEC 60068-2-82:2007) Essais denvironnement - Partie 2-82: Essais - Essai Tx: Mthodes dessai des trichites (“moustaches/whiskers“) pour les composants lectriques et lectroniques (CEI 60068-2-82:2007) Umgebungseinflsse - Teil 2-82: Prfungen - Prfung Tx: Whisker-Prfverfahren fr elektronische
8、 und elektrische Bauelemente (IEC 60068-2-82:2007) This European Standard was approved by CENELEC on 2007-06-01. 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 an
9、y alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language mad
10、e by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, E
11、stonia, 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. EN 60068-2-82:2007 2 Foreword The text of document 91/651/FDIS,
12、 future edition 1 of IEC 60068-2-82, prepared by IEC TC 91, Electronics assembly technology, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60068-2-82 on 2007-06-01. The following dates were fixed: latest date by which the EN has to be implemented at national level
13、by publication of an identical national standard or by endorsement (dop) 2008-03-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2010-06-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60068-2-82
14、:2007 was approved by CENELEC as a European Standard without any modification. _ 3 EN 60068-2-82:2007 CONTENTS 1 Scope . H5 2 Normative references H5 3 Terms and definitions H5 4 Test equipment H6 4.1 Desiccator H6 4.2 Humidity chamber. H6 4.3 Thermal cycling chamber H6 4.4 Optical microscope . H6 4
15、.5 Scanning electron microscope microscopy H6 4.6 Fixing jig H7 5 Preparation for test H7 5.1 General H7 5.2 Selection of test methods H7 5.3 Storage conditions prior to testing. H7 5.4 Handling of the specimen H7 5.5 Preconditioning by heat treatment. H7 5.6 Specimen preparation by leads forming. H
16、8 6 Test condition H9 6.1 Ambient test . H9 6.2 Damp heat test . H9 6.3 Temperature cycling test. H9 7 Test schedule H10 7.1 Procedure for test method selection H10 7.2 Initial measurement H11 7.3 Test . H11 7.4 Recovery H11 7.5 Intermediate or final assessment. H11 8 Information to be given in the
17、relevant specification H11 9 Minimum requirements for a test report H12 Annex A (normative) Measurement of the whisker length . H13 Annex B (informative) Examples of whiskers . H14 Annex C (informative) Guidance on the sample lots and test schedules . H16 Annex D (informative) Guidance on acceptance
18、 criteria . H18 Annex E (informative) Background on whisker growth H20 Annex F (informative) Background on ambient test H21 Annex G (informative) Background on damp heat test H23 Annex H (informative) Background on temperature cycling test H26 Annex ZA (normative) Normative references to internation
19、al publications with their corresponding European publications32 Bibliography H31 EN 60068-2-82:2007 4 Figure A.1 Definition of the whisker length. H13 Figure B.1 Nodule. H14 Figure B.2 Column whisker . H14 Figure B.3 Filament whisker H14 Figure B.4 Kinked whisker. H15 Figure B.5 Spiral whisker H15
20、Figure D.1 Smallest distance of components and circuit boards . H18 Figure F.1 Whisker growth of tin plating in ambient test condition. H22 Figure G.1 Growth of the oxide layer in damp heat conditions H24 Figure G.2a Growth of whiskers in damp heat conditions . H24 Figure G.2b Growth of whiskers in
21、damp heat conditions . H25 Figure G.2 Growth of whiskers H25 Figure H.1 Distribution of whisker length grown on FeNi (Alloy42) base material H27 Figure H.2 Whisker grown on FeNi (Alloy42) base material H28 Figure H.3 Relationship of and number of cycles for whisker growth on FeNi (Alloy 42) base mat
22、erial . H28 Figure H.4 Whisker growth on Cu based leadframes (QFP) in temperature cycling tests H30 Table 1 Methods of preconditioning: Soldering simulation H8 Table 2 Methods of preconditioning: Soldering. H8 Table 3 Severities of the ambient test H9 Table 4 Severities of the temperature cycling te
23、st: temperature H9 Table 5 Severities of the temperature cycling test: cycles H10 Table 6 Suitability of test methods for different plating situations . H10 Table H.1 Example for a relationship between realistic application conditions and test conditions . H29 5 EN 60068-2-82:2007 ENVIRONMENTAL TEST
24、ING Part 282: Tests Test Tx: Whisker test methods for electronic and electric components 1 Scope This part of IEC 60068 specifies whisker tests for electric or electronic components representing the finished stage, with tin or tin-alloy finish. However, the standard does not specify tests for whiske
25、rs that may grow as a result of external mechanical stress. This test method is employed by a relevant specification (international component or application specification) with transfer of the test severities to be applied and with defined acceptance criteria. Where tests described in this standard
26、are considered for other components, e.g. mechanical parts as used in electrical or electronic equipment, it should be ensured that the material system and whisker growth mechanisms are comparable. 2 Normative references The following referenced documents are indispensable for the application of thi
27、s document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60068-1:1988, Environmental testing Part 1: General and guidance IEC 60068-2-14, Environmental testing Part 2-14: Tests Test
28、 N: Change of temperature IEC 60068-2-20:1979, Environmental testing Part 2-20: Tests Test T: Soldering IEC 60068-2-58:2004, Environmental testing Part 2-58: Tests Test Td: Test methods for solderability, resistance to dissolution of metallization and to soldering heat of surface mounting devices (S
29、MD) IEC 60068-2-78, Environmental testing Part 2-78: Test Cab: Damp heat, steady state IEC 61192-3:2002, Workmanship requirements for soldered electronic assemblies Part 3: Through-hole mount assemblies IEC 61760-1:2006, Surface mounting technology Part 1: Standard method for the specification of su
30、rface mounting components (SMDs) 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 60068-1, as well as the following, apply. 3.1 whisker metallic protrusion which spontaneously grows during storage or use EN 60068-2-82:2007 6 NOTE 1 Whiskers typically
31、do not require any electrical field for their growth and may not be mixed with products of electrochemical migration. Typical signs of whiskers include: striations in growth direction; typically no branching; typically constant diameters. Exceptions are known, but rare and may require detailed inves
32、tigation. For the purposes of this standard, whiskers are considered if they have an aspect ratio (length/width) greater than 2, they have a length of 10 m or more. NOTE 2 For the purposes of this standard, whiskers have the following characteristics: they can be kinked, bent, or twisted; they usual
33、ly have a uniform cross-sectional shape; they may have rings around the circumference of the column. NOTE 3 Whiskers are not to be confused with dendrites which are fern-like growths on the surface of a material which can be formed as a result of electro-migration of an ionic species or produced dur
34、ing solidification. 3.2 material system termination consists of the following elements: a) base material; b) underlayer, if any, located under the final plating; c) final tin or tin alloy plating. NOTE There may be additional layers between the base material and the underlayer. The penultimate layer
35、 is the used bulk material or the deposited layer underneath the final tin or tin alloy plating of the component. 4 Test equipment The test equipment shall comprise the following elements: 4.1 Desiccator The desiccator shall be capable of providing the conditions of temperature and humidity specifie
36、d in 6.1. 4.2 Humidity chamber The humidity chamber shall meet all the requirements of IEC 60068-2-78 and be capable of providing the conditions specified in 6.2. 4.3 Thermal cycling chamber The thermal cycling chamber shall meet all the requirements of IEC 60068-2-14, test Na and be capable of prov
37、iding the conditions specified in 6.3. 4.4 Optical microscope An optical stereo-microscope with a magnification of at least 50 times and an appropriate illumination, capable of detecting whiskers with a length of 10 m. If used for measurement, the microscope shall be equipped with a scale or electro
38、nic detection system capable for length measurement with an accuracy of at least 5 m. 4.5 Scanning electron microscope A scanning electron microscope (SEM) capable of investigating the surface of the specimen, preferably equipped with a handling system capable to tilt and rotate the specimen. 7 EN 6
39、0068-2-82:2007 4.6 Fixing jig The fixture jig shall be capable of setting samples in any of the test chambers specified in 4.1, 4.2 and 4.3 without affecting compliance with the specified requirements. The jig should also be attachable to the optical microscope or be appropriately small in size so t
40、hat it can be inserted in the SEM sample chamber. 5 Preparation for test 5.1 General The samples shall represent finished products as supplied to the market. NOTE Guidance on suitable sample sizes is provided in Annex C. 5.2 Selection of test methods Choose the appropriate test method according to t
41、he type of final plating, underlayer and base material of the specimen according to Table 6. 5.3 Storage conditions prior to testing The specimen shall be kept for at least 2 h in the standard atmospheric conditions defined in IEC 60068-1, 5.3.1 prior to any preconditioning or test. 5.4 Handling of
42、the specimen It is recommended to hold the specimen with a fixture jig as specified in 4.6 to prevent them from being contaminated unexpectedly. The fixture jig shall not contact the metallic surfaces of the specimen to be tested. The sample shall be handled carefully to prevent the grown whiskers f
43、rom falling away unexpectedly. Broken whiskers shall be recorded, see 7.4. Where there is a possibility of grown whiskers to drop down, an appropriate fixture jig design shall be considered in advance of the test. Conductive sputter coating typically used to aid SEM inspection, such as C, Pt, or Au,
44、 shall not be deposited on the specimen. 5.5 Preconditioning by heat treatment 5.5.1 Soldering simulation prior to ambient and damp heat test (see 6.1 and 6.2) a) Components intended for soldering Before soldering simulation, the specimen of material descriptions case 1.1, case 3 or case 4 shall hav
45、e been stored under room temperature for more than 30 days after the last manufacturing process, e.g. as indicated by the date code of the product. Unless otherwise specified by the relevant specification, the components shall be submitted to a soldering simulation according to Table 1 without the u
46、se of solder and without contact to any metal surface. EN 60068-2-82:2007 8 Table 1 Methods of preconditioning Soldering simulation Soldering simulation Component type First half of the sample Second half of the sample SMD Reflow heat treatment according to Table 3 (Group 3) of 8.1.2.1, IEC 60068-2-
47、58 None Other Bath with inert liquid 1 according to test Ta, method 1 of IEC 60068-2-20 Dipping depth: max. 4 mm. None 1e.g. Perfluoropolyether PFPE. After preconditioning the test shall be started within 168 h. Conditions of thermal preconditioning shall be recorded. b) Components not intended for
48、soldering No thermal preconditioning shall be applied. 5.5.2 Soldering simulation prior to temperature cycling test (see 6.3) a) Components intended for soldering Before soldering, the specimen of material descriptions case 1.1, case 3 or case 4 shall have been stored under room temperature for more
49、 than 30 days after the last manufacturing process, e.g. as indicated by the date code of the product. Unless otherwise specified by the relevant specification, the components may be assembled onto printed circuit boards. The circuit board material shall be epoxide woven glass with a thickness of (1,6 0,2) mm. The assembly process shall be according to Table 2. Table 2
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