1、 IEC 60068-2-82 Edition 1.0 2007-05 INTERNATIONAL STANDARD Environmental testing Part 2-82: Tests Test XW 1 : Whisker test methods for electronic and electric components IEC 60068-2-82:2007(E) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2007 IEC, Geneva, Switzerland All rights reserved. Unless
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9、vironmental testing Part 2-82: Tests Test XW 1 : Whisker test methods for electronic and electric components INTERNATIONAL ELECTROTECHNICAL COMMISSION V ICS 19.040; 31.190 PRICE CODE ISBN 2-8318-9162-0 Registered trademark of the International Electrotechnical Commission 2 60068-2-82 IEC:2007(E) CON
10、TENTS FOREWORD.4 1 Scope.6 2 Normative references .6 3 Terms and definitions .6 4 Test equipment.7 4.1 Desiccator.7 4.2 Humidity chamber .7 4.3 Thermal cycling chamber.7 4.4 Optical microscope7 4.5 Scanning electron microscope microscopy 7 4.6 Fixing jig .8 5 Preparation for test.8 5.1 General .8 5.
11、2 Selection of test methods 8 5.3 Storage conditions prior to testing .8 5.4 Handling of the specimen 8 5.5 Preconditioning by heat treatment .8 5.6 Specimen preparation by leads forming.9 6 Test condition.10 6.1 Ambient test 10 6.2 Damp heat test10 6.3 Temperature cycling test .10 7 Test schedule.1
12、1 7.1 Procedure for test method selection 11 7.2 Initial measurement.12 7.3 Test.12 7.4 Recovery.12 7.5 Intermediate or final assessment.12 8 Information to be given in the relevant specification .12 9 Minimum requirements for a test report 13 Annex A (normative) Measurement of the whisker length.14
13、 Annex B (informative) Examples of whiskers15 Annex C (informative) Guidance on the sample lots and test schedules.17 Annex D (informative) Guidance on acceptance criteria .19 Annex E (informative) Background on whisker growth21 Annex F (informative) Background on ambient test 22 Annex G (informativ
14、e) Background on damp heat test24 Annex H (informative) Background on temperature cycling test27 Bibliography32 60068-2-82 IEC:2007(E) 3 Figure A.1 Definition of the whisker length .14 Figure B.1 Nodule15 Figure B.2 Column whisker 15 Figure B.3 Filament whisker.15 Figure B.4 Kinked whisker .16 Figur
15、e B.5 Spiral whisker .16 Figure D.1 Smallest distance of components and circuit boards.19 Figure F.1 Whisker growth of tin plating in ambient test condition 23 Figure G.1 Growth of the oxide layer in damp heat conditions25 Figure G.2a Growth of whiskers in damp heat conditions .25 Figure G.2b Growth
16、 of whiskers in damp heat conditions .26 Figure G.2 Growth of whiskers.26 Figure H.1 Distribution of whisker length grown on FeNi (Alloy42) base material28 Figure H.2 Whisker grown on FeNi (Alloy42) base material29 Figure H.3 Relationship of and number of cycles for whisker growth on FeNi (Alloy 42)
17、 base material 29 Figure H.4 Whisker growth on Cu based leadframes (QFP) in temperature cycling tests .31 Table 1 Methods of preconditioning: Soldering simulation9 Table 2 Methods of preconditioning: Soldering.9 Table 3 Severities of the ambient test 10 Table 4 Severities of the temperature cycling
18、test: temperature .10 Table 5 Severities of the temperature cycling test: cycles 11 Table 6 Suitability of test methods for different plating situations .11 Table H.1 Example for a relationship between realistic application conditions and test conditions 30 4 60068-2-82 IEC:2007(E) INTERNATIONAL ELE
19、CTROTECHNICAL COMMISSION _ ENVIRONMENTAL TESTING Part 2-82: Tests Test XW 1 : Whisker test methods for electronic and electric components FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committee
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29、 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 pate
30、nt rights. International Standard IEC 60068-2-82 has been prepared by IEC technical committee 91: Electronics assembly technology. The text of this standard is based on the following documents: FDIS Report on voting 91/651/FDIS 91/685/RVD Full information on the voting for the approval of this stand
31、ard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. 60068-2-82 IEC:2007(E) 5 A list of all parts in the IEC 60068 series, under the general title Environmental testing, can be found on the IEC web
32、site. The committee has decided that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, rep
33、laced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. The contents of the corrigendum of December 2009 have been included in this copy. 6 60068-2-82 IEC:2007(E) ENVIRONMENTAL TESTING Part 2-82: Tests Test XW 1 : Whisker test methods for electr
34、onic 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 whiskers that may grow as a result of external mechanical stress.
35、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 are considered for other components, e.g. mechanical parts a
36、s 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 this document. For dated references, only the edition cited app
37、lies. 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 N: Change of temperature IEC 60068-2-20:1979, Environmental
38、 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 (SMD) IEC 60068-2-78, Environmental testing Part 2-78: Test Ca
39、b: 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 surface mounting components (SMDs) 3 Terms and definitions For
40、 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 60068-2-82 IEC:2007(E) 7 NOTE 1 Whiskers typically do not require any electrical field for their growth and
41、 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 investigation. For the purposes of this standard, whiskers ar
42、e 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 usually have a uniform cross-sectional shape; they may have r
43、ings 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 during solidification. 3.2 material system termination cons
44、ists 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 is the used bulk material or the deposited layer undern
45、eath 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 specified in 6.1. 4.2 Humidity chamber The humidity chamber shal
46、l 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 providing the conditions specified in 6.3. 4.4 Optical micro
47、scope 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 electronic detection system capable for length measurement with
48、 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. 8 60068-2-82 IEC:2007(E) 4.6 Fixing jig The fixture jig shall
49、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 that 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
