IEC_TR_61191-8-2021.pdf

IEC TR 61191-8 Edition 1.0 2021-03 TECHNICAL REPORT Printed board assemblies Part 8:Voiding in solder joints of printed board assemblies for use in automotive electronic control units Best practices IEC TR 61191-8:2021-03(en)colourinside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2021 IEC,Geneva,Switzerland All rights reserved.Unless otherwise specified,no part of this publication may be reproduced or utilized in any form or by any means,electronic or mechanical,including photocopying and microfilm,without permission in writing from either IEC or IECs member National Committee in the country of the requester.If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,please contact the address below or your local IEC member National Committee for further information.IEC Central Office Tel.:+41 22 919 02 11 3,rue de Varemb infoiec.ch CH-1211 Geneva 20 www.iec.ch Switzerland About the IEC The International Electrotechnical Commission(IEC)is the leading global organization that prepares and publishes International Standards for all electrical,electronic and related technologies.About IEC publications The technical content of IEC publications is kept under constant review by the IEC.Please make sure that you have the latest edition,a corrigendum or an amendment might have been published.IEC publications search-webstore.iec.ch/advsearchform The advanced search enables to find IEC publications by a variety of criteria(reference number,text,technical committee,).It also gives information on projects,replaced and withdrawn publications.IEC Just Published-webstore.iec.ch/justpublished Stay up to date on all new IEC publications.Just Published details all new publications released.Available online and once a month by email.IEC Customer Service Centre-webstore.iec.ch/csc If you wish to give us your feedback on this publication or need further assistance,please contact the Customer Service Centre:salesiec.ch.IEC online collection-oc.iec.ch Discover our powerful search engine and read freely all the publications previews.With a subscription you will always have access to up to date content tailored to your needs.Electropedia-www.electropedia.org The worlds leading online dictionary on electrotechnology,containing more than 22 000 terminological entries in English and French,with equivalent terms in 18 additional languages.Also known as the International Electrotechnical Vocabulary(IEV)online.INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 31.180;31.190 IEC TR 61191-8 ISBN 978-2-8322-9575-5 Edition 1.0 2021-03 Registered trademark of the International Electrotechnical Commission TECHNICAL REPORT Warning!Make sure that you obtained this publication from an authorized distributor.Printed board assemblies Part 8:Voiding in solder joints of printed board assemblies for use in automotive electronic control units Best practices colourinside 2 IEC TR 61191-8:2021 IEC 2021 CONTENTS FOREWORD.4 INTRODUCTION.6 1 Scope.7 2 Normative references.7 3 Terms and definitions.7 4 Technical background of voiding in solder joints and potential impact on assembly reliability.8 4.1 Void categories.8 4.2 Void occurrence in surface-mount technology solder joints.11 4.3 Influence of voiding on solder joint performance.14 4.3.1 Introductory remarks.14 4.3.2 Thermomechanical reliability.15 4.3.3 Mechanical reliability.17 4.3.4 Thermal functionality.18 4.3.5 Electrical functionality.19 5 Determination of voiding levels in solder joints.20 5.1 Instrumentation available for investigation of voiding in solder joints.20 5.1.1 General.20 5.1.2 X-ray inspection equipment operating in two-dimensional mode.20 5.1.3 X-ray inspection equipment operating in three-dimensional mode.21 5.2 Challenges for the X-ray inspection of voiding:two case studies.22 5.2.1 Influence of shadowing effects on measuring reproducibility first results for 3D X-ray inspection equipment.22 5.2.2 Influence of X-ray parameters.23 5.2.3 Manual determination of voiding levels in solder joints in sample production.24 6 Recommendations for sample qualification.25 7 Recommendations for mass production.26 7.1 General remarks.26 7.2 Ramp-up quality assurance for voiding.26 7.3 X-ray sampling inspection.26 7.3.1 General.26 7.3.2 Control limits.26 7.3.3 Exceeding the control limits.26 7.4 Process control without X-ray sampling inspection.27 Annex A(informative)Types of voids and guidelines for acceptability.28 A.1 Types of voids Summary.28 A.2 Typical voiding levels of components and guidelines for acceptability.29 A.2.1 General.29 A.2.2 Ball-grid array(BGA)components with collapsing balls.30 A.2.3 Bottom-termination components involving a lead-frame construction,as quad-flat no lead packages,dual-flat no lead packages.30 A.2.4 Exposed pads of components with gull wing solder joints as quad-flat packages.31 A.2.5 Transistors with thermal plane as D2PAK and TOLL(TO lead-less).31 A.2.6 Rectangular or square end chip components(2,3