Humidity and Electronics: Corrosion Reliability Issues and Preventive Measures PDF
Preview Humidity and Electronics: Corrosion Reliability Issues and Preventive Measures
HUMIDITY AND ELECTRONICS This pageintentionallyleftblank Woodhead Publishing Series in Materials HUMIDITY AND ELECTRONICS CORROSION RELIABILITY ISSUES AND PREVENTIVE MEASURES R A AJAN MBAT K P AMILA IOTROWSKA WoodheadPublishingisanimprintofElsevier TheOfficers’MessBusinessCentre,RoystonRoad,Duxford,CB224QH,UnitedKingdom 50HampshireStreet,5thFloor,Cambridge,MA02139,UnitedStates TheBoulevard,LangfordLane,Kidlington,OX51GB,UnitedKingdom Copyright©2022ElsevierLtd.Allrightsreserved. Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,elec- tronicormechanical,includingphotocopying,recording,oranyinformationstorageandretrieval system,withoutpermissioninwritingfromthepublisher.Detailsonhowtoseekpermission,fur- therinformationaboutthePublisher’spermissionspoliciesandourarrangementswithorganiza- tionssuchastheCopyrightClearanceCenterandtheCopyrightLicensingAgency,canbefoundat ourwebsite:www.elsevier.com/permissions. Thisbookandtheindividualcontributionscontainedinitareprotectedundercopyrightbythe Publisher(otherthanasmaybenotedherein). Notices Knowledgeandbestpracticeinthisfieldareconstantlychanging.Asnewresearchandexperience broadenourunderstanding,changesinresearchmethods,professionalpractices,ormedicaltreat- mentmaybecomenecessary. Practitionersandresearchersmustalwaysrelyontheirownexperienceandknowledgeinevaluat- ingandusinganyinformation,methods,compounds,orexperimentsdescribedherein.Inusing suchinformationormethodstheyshouldbemindfuloftheirownsafetyandthesafetyofothers, includingpartiesforwhomtheyhaveaprofessionalresponsibility. Tothefullestextentofthelaw,neitherthePublishernortheauthors,contributors,oreditors, assumeanyliabilityforanyinjuryand/ordamagetopersonsorpropertyasamatterofproducts liability,negligenceorotherwise,orfromanyuseoroperationofanymethods,products,instruc- tions,orideascontainedinthematerialherein. BritishLibraryCataloguing-in-PublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary LibraryofCongressCataloging-in-PublicationData AcatalogrecordforthisbookisavailablefromtheLibraryofCongress ISBN:978-0-323-90853-5(print) ISBN:978-0-323-90854-2(online) ForinformationonallWoodheadPublishingpublications visitourwebsiteathttps://www.elsevier.com/books-and-journals Publisher:MatthewDeans AcquisitionsEditor:KaylaDosSantos EditorialProjectManager:IsabellaC.Silva ProductionProjectManager:AnithaSivaraj CoverDesigner:GregHarris TypesetbyMPSLimited,Chennai,India Contents Preface vii 1. Humidity and electronics: corrosion perspectives 1 1.1 Scopeofthisbook 1 1.2 Historyofelectronics 6 1.3 Useofmaterialsinmodernelectronics 13 1.4 Electronicsandcorrosionreliabilitytoday 15 References 18 2. Basic theory of corrosion and important failure mechanisms connected to corrosion in electronics 19 2.1 Definitionofcorrosion 19 2.2 Corrosioninelectronicsversusconventionalcorrosionscenario 21 2.3 Electrochemicalcorrosionofmetalsunderwetconditions 24 2.4 Corrosionfailuremodesforelectronicsandrelatedmechanisms 48 References 88 3. Factors determining water film buildup on surfaces and relevance to corrosion in electronics 93 3.1 Characteristicsofmoisture 94 3.2 Interactionofhumiditywithelectronics 103 References 138 4. Importance of PCBA cleanliness in humidity interaction with electronics 141 4.1 Natureoftheresidueandhumidityinteraction 143 4.2 ContaminationoriginatingfromthePCBAmanufacturingprocess 147 4.3 Contaminationrelatedtooperatorhandling 181 4.4 Contaminationoriginatingfromtheuserenvironment(servicelife) 182 References 191 v vi Contents 5. Materials and processes for electronic devices and components: how they contribute to corrosion reliability? 197 5.1 Manufacturingprocessofbareprintedcircuitboard 199 5.2 Componentassembling,mounting,andsolderingprocesses 214 5.3 Electroniccomponents 225 References 249 6. Examples of corrosion failures in electronics: summary of case studies 251 6.1 Failuresduetoprocess-relatedcleanlinessissuesasamainfactor 251 6.2 Failurescausedbycorrosivegasesandhumidity 259 6.3 Failuresduetomaterialcombinationsandenvironment 271 6.4 Failuresofhigh-powerelectronicsystemsduetoenvironmentalconditions 278 References 281 7. Preventive measures for corrosion in electronics: intrinsic and extrinsic strategies 285 7.1 Intrinsicmethodsforcorrosionmitigationinelectronics 286 7.2 Extrinsicmethodsforenhancingthehumidityrobustness 300 References 336 8. Corrosion reliability testing, standards, and failure analysis 339 8.1 TestingofPCBAcleanlinessandcontaminationlevel 341 8.2 Testsinvestigatingthecleanlinessandcorrosioneffects 350 8.3 Methodologyofacceleratedtestingofelectronicequipment 374 8.4 Spectroscopicandmicroscopicmethods 376 References 379 Index 381 Preface Today, electronics is used everywhere as a part of industrial systems and as consumer electronics, while the intended use of electronic sys- tems will be exponentially increased in the future. The focus of 21st- century technological development is oriented toward sustainability. Today’s three main global challenges are energy, clean water, and clean air, and electronics is an integral part of this development, while, on the other side, the everyday life of a person is closely connected to the use of several electronic gadgets and their performance. Efficient electrical energy production, distribution, and utilization are the most important aspects for sustainable development, especially considering the growth in the renewable energy sector within the next 20 years, and reliable electronics are thekey components. The effect of exposure climate on the robustness and reliability of electronicsismoresignificanttodaythanbeforeduetotheirwidespread use exposing them to all types of climatic conditions. Although humid- ity is the key factor contributing to the robustness and reliability issues, other atmospheric conditions such as the presence of aerosol and gas- eous contaminations also influence the device performance. All result in several corrosion failure modes causing intermittent or permanent fail- ures at the component-, Printed Circuit Board Assembly (PCBA)-, or system level. There exist other inherent factors related to the electronic systems contributing to these increased robustness and reliability issues such as the multimaterial usage, miniaturization, electrical aspects, or process-related issues, all while the systems are expected to perform in mild to harsh climatic conditions without failure occurrence. Such pro- blems will increase significantly in the future due to the enhanced inte- gration of electronics as part of all technological sectors, for example, in connection with a green transition and e-mobility. Today, the knowl- edge on corrosion reliability issues of electronics and how to tackle them are limited among those involved in developing and using the electronics. Difficulty inunderstandingthecorrosion reliability issues ofelectron- icsisalsorelatedtotheinterdisciplinarynatureofthissubjectcompared to the conventional corrosion topics. Although the fundamental basis of the failure mechanisms of corrosion in electronics is centered on electro- chemical or chemical aspects, the resulting effect on the product is man- ifested as electrical functional issues. Additionally, behavior of the vii viii Preface materials(individuallyorincombinationduetothemultimaterial usage and manufacturing process-related issues) plays a key role. For exam- ple, PCBA as a whole corroding substrate is too complex to understand as it does not involve only the material- and corrosion-related features, but also corrosion mechanisms that interact with the electrical and elec- tronic functionality of thesystem. This book attempts to provide a discussion on these topics at a basic level with an intention to cover the readers from across the interdisci- plinary areas, while providing a more detailed discussion on topics with well-referenced coverage of literature—all to build the knowledge from a basic to the application level. The book contains a mix of aca- demic and industrial relevance, making it suitable for a detailed under- standing of the humidity-related issues in electronics, both for the materials and corrosion experts and for electronics and electrical experts. Our ambition is for the book to be useful for researchers, aca- demics, and the industrial community involved in materials, corrosion, and electronics reliability aspects. The methodology used in the book is based on a proactive-design-prevention perspective. To the best of author’s knowledge, this is the first book in this area comprehensively discussingthese topics. Today,manyfailuresinelectronics arenotidentifiedduetocorrosion because of two factors: (1) difficulty in locating the humidity-related failures as the traces of failure could disappear during disassembling and (2) lack of knowledge on the corrosion failures and related factors among those involved in failure analysis, therefore, compromising the quality of the failure evaluation. Lack of knowledge also influences the possibilityofimplementingthepreventivemeasures,asthereisnocom- prehensive knowledge on steps that could be taken to instill the corro- sion reliability perspective from the production stage. This book tried to fill this gap by attempting to show a number of intrinsic and extrinsic possibilities for preventing the occurrence of corrosion failures in elec- tronic devices. The limitation of any book is related to the difficulty in covering all relevant subtopics in detail. Our aim is to provide a broad coverage encompassing all required topics in relation to the title of the book; however, this meant cutting short on certain topics depending on their relative importance. To address this issue, chapters are well referenced for providing additional information to thereader. We strongly urgethe readers to further explore the topics using the references provided at theendof each chapter. All books are expected to contain some errors due to the massive nature of the work. We expect the same to be true for this book despite the repeated reading and editing exercises. If you find any mistakes or ix Preface discrepancies, please inform us so that they can be corrected in the future. There are many people that we owe our sincere thanks in connection with preparing this book. Many topics covered in it contain a summa- rized knowledge from a number of research activities and published work from the CELCORR research group based at DTU. In this respect, we are indebted to several students and researchers who have contrib- utedtotheseactivitiesinthelast15years,although,duetospacelimita- tions, all names cannot be mentioned. Our foremost appreciation goes to Daniel Minzari, Umadevi Rathinavelu, Vadimas Verdingovas, Helene Conseil-Gudla, Morten Jellesen, Feng Li, Salil Joshy, Simone Lauser, Ioannis Mantis, Sajjad Bahrebar, Anish Rao, Abhijeet Yadav, and Peter Westermann. We are also indebted to the collaborators from our indus- trial partners, namely, Danfoss, Grundfos, Vestas, Eltek, Volvo, Widex, Inventec, Wevo, and Bosch, who have contributed to generating the knowledge relevant to this book. Many other research and industrial partner’s contributions, through their participation in various research programs during the last 15 years, are also acknowledged, although their namesarenot mentioned. Additionally, wewouldlike to acknowl- edge Mathilde Buret (Inventec), Chris Hunt (GEN3 systems), and Lutz Muller (Bosch) for providing pictures for illustrations. We are also grateful to the staff of Elsevier for a great collaboration and profession- alism during this project. Finally, we would like to thank our family members Indu, Deepthi, Tina, Hanna, Ryszard, and Hristo for providing enough time for us to sparefor this work, which otherwisebelongs to them. Rajan Ambat and Kamila Piotrowska
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