IEC 60068-2-82
Edition 2.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Environmental testing –
Part 2-82: Tests – Test Xw
1
: Whisker test methods for components and parts
used in electronic assemblies
Essais d'environnement –
Partie 2-82: Essais – Essai Xw
1
: Méthodes de vérification des trichites
pour les composants et les pièces utilisés dans les ensembles électroniques
IEC 60068-2-82:2019-05(en-fr)
®
colour
inside
IEC 60068-2-82
Edition 2.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Environmental testing –
Part 2-82: Tests – Test Xw
1
: Whisker test methods for components and parts
used in electronic assemblies
Essais d'environnement –
Partie 2-82: Essais – Essai Xw
1
: Méthodes de vérification des trichites
pour les composants et les pièces utilisés dans les ensembles électroniques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 19.040
ISBN 978-2-8322-6863-6
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
®
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.
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inside
– 2 – IEC 60068-2-82:2019 © IEC 2019
CONTENTS
FOREWORD ........................................................................................................................... 4
1 Scope .............................................................................................................................. 6
2 Normative references ...................................................................................................... 6
3 Terms and definitions ...................................................................................................... 7
4 Test equipment ................................................................................................................ 9
4.1 General ................................................................................................................... 9
4.2 Desiccator .............................................................................................................. 9
4.3 Humidity chamber ................................................................................................... 9
4.4 Thermal cycling chamber ........................................................................................ 9
4.5 Equipment for visual inspection ............................................................................... 9
4.5.1 Scanning electron microscope ......................................................................... 9
4.5.2 Optical microscope/Confocal laser microscope ................................................ 9
4.6 Fixing jig ................................................................................................................. 9
5 Preparation for test ........................................................................................................ 10
5.1 Selection of relevant tests ..................................................................................... 10
5.1.1 General ......................................................................................................... 10
5.1.2 Storage conditions prior to testing ................................................................. 11
5.1.3 Pre-aging (storage in the supply chain) before testing ................................... 12
5.2 Handling of the specimens .................................................................................... 12
5.3 Sample size .......................................................................................................... 12
5.4 Surface and base materials for test selection ........................................................ 12
5.5 Preconditioning of test specimen not intended for soldering/welding ..................... 13
5.5.1 Preconditioning of test specimen intended for press-fit applications ............... 13
5.5.2 Preconditioning of test specimen intended for mechanical loads other
than press fit ................................................................................................. 14
5.6 Preconditioning of test specimen intended for soldering/welding ........................... 14
5.6.1 General ......................................................................................................... 14
5.6.2 Mechanical pretreatment ............................................................................... 14
5.6.3 Heat pre-treatment ........................................................................................ 15
6 Test conditions .............................................................................................................. 15
6.1 General ................................................................................................................. 15
6.2 Ambient test .......................................................................................................... 15
6.3 Damp heat test ..................................................................................................... 15
6.4 Temperature cycling test ....................................................................................... 16
6.5 Ambient test for press-fit applications ................................................................... 16
7 Monitoring and technological similarity .......................................................................... 17
7.1 Monitoring ............................................................................................................. 17
7.2 Technological similarity ......................................................................................... 17
8 Test and assessment ..................................................................................................... 18
8.1 Whisker investigation ............................................................................................ 18
8.2 Initial measurement .............................................................................................. 18
8.3 Test ...................................................................................................................... 18
8.4 Recovery .............................................................................................................. 18
8.5 Intermediate or final assessment for each test condition ....................................... 18
8.5.1 Fixed threshold length for pass/fail classification ........................................... 18
8.5.2 Statistical assessment of whisker lengths ...................................................... 19
IEC 60068-2-82:2019 © IEC 2019 – 3 –
9
Technology or manufacturing process changes ............................................................. 19
10 Content of final report .................................................................................................... 20
Annex A (normative) Measurement of whisker length ........................................................... 22
Annex B (informative) Examples of whiskers ........................................................................ 23
Annex C (informative) Guidance on acceptance criteria ....................................................... 25
C.1 Risks attributed to whiskers .................................................................................. 25
C.2 Acceptance criteria for whisker length ................................................................... 25
C.3 Acceptance criteria for whisker density ................................................................. 26
C.4 Statistical evaluation of number and length of whiskers......................................... 26
C.5 Example of statistic evaluation .............................................................................. 26
Annex D (informative) Technical background of whisker growth ........................................... 29
Annex E (normative) Transition scenarios for the changeover of the damp-heat test
conditions ............................................................................................................................. 30
Bibliography .......................................................................................................................... 32
Figure 1 – Cross-sectional views of component termination surface finishes ........................... 8
Figure 2 – Selection of test methods ..................................................................................... 11
Figure 3 –
Flow for treatment and/or bending and heat treatment
.......................................... 14
Figure A.1 – Estimation of whisker length ............................................................................. 22
Figure A.2 – Example for whisker length measurement ......................................................... 22
Figure B.1 – Nodule .............................................................................................................. 23
Figure B.2 – Column whisker ................................................................................................ 23
Figure B.3 – Filament whisker ............................................................................................... 24
Figure B.4 – Kinked whisker ................................................................................................. 24
Figure B.5 – Spiral whisker ................................................................................................... 24
Figure C.1 – Smallest distance of components and circuit boards ......................................... 25
Figure C.2 – Histogram of whisker lengths and fitted log-normal distribution ......................... 27
Figure C.3 – Histogram of whisker lengths and fitted log-normal distribution ......................... 28
Figure C.4 – Histogram of whisker lengths and fitted log-normal distribution ......................... 28
Figure E.1 –Transition paths for damp-heat testing of components ....................................... 30
Table 1 – Material systems recognized for effective whisker mitigation ................................. 13
Table 2 –
Preconditioning conditions and test legs for components for different
assembly processes
............................................................................................................. 15
Table 3 – Conditions for the ambient test .............................................................................. 15
Table 4 – Conditions for the damp heat test .......................................................................... 16
Table 5 – Conditions for the ambient test .............................................................................. 16
Table 6 – Conditions for the ambient test applicable to press-fit terminations ........................ 17
Table 7 – Classification for measured whisker length ............................................................ 19
Table 8 – Surface finish technology and manufacturing process change acceptance
parameters
................................................................................................
........................... 19
Table 9 – Final report ............................................................................................................ 21
Table C.1 – Classification for measured whisker length ........................................................ 27
Table E.1 – Conclusion matrix for parallel damp heat testing ................................................ 31
– 4 – IEC 60068-2-82:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 2-82: Tests – Test Xw
1
: Whisker test methods for components
and parts used in electronic assemblies
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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International Standard IEC 60068-2-82 has been prepared by IEC technical committee 91:
Electronics assembly technology.
This second edition cancels and replaces the first edition published in 2007. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– extension of the scope of the test standard from electronic to electromechanic components
and press-fit pins, which are used for assembly and interconnect technology;
– significant reduction of the testing effort by a knowledge-based selection of test conditions
i.e. tests not relevant for a given materials system can be omitted (see Annex D);
– harmonization with JESD 201A by omission of severities M, N for temperature cycling
tests;
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