Mitigating Tin Whisker Risks E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Serie: Wiley Series on Processing of Engineering Materials
• Sprache: Englisch

Seitenzahl: 423

Veröffentlichungsjahr: 2016

Beschreibung

Discusses the growth mechanisms of tin whiskers and the effective mitigation strategies necessary to reduce whisker growth risks

This book covers key tin whisker topics, ranging from fundamental science to practical mitigation strategies. The text begins with a review of the characteristic properties of local microstructures around whisker and hillock grains to identify why these particular grains and locations become predisposed to forming whiskers and hillocks. The book discusses the basic properties of tin-based alloy finishes and the effects of various alloying elements on whisker formation, with a focus on potential mechanisms for whisker suppression or enhancement for each element. Tin whisker risk mitigation strategies for each tier of the supply chain for high reliability electronic systems are also described.

• Discusses whisker formation factors including surface grain geometry, crystallographic orientation-dependent surface grain boundary structure, and the localization of elastic strain/strain energy density distribution
• Examines how whiskers and hillocks evolve in time through real-time studies of whisker growth with the scanning electron microscope/focused ion beaming milling (SEM/FIB)
• Covers characterization methods of tin and tin-based alloy finishes such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD)
• Reviews theories of mechanically-induced tin whiskers with case studies using pure tin and other lead-free finishes shown to evaluate the pressure-induced tin whiskers

Mitigating Tin Whisker Risks: Theory and Practice is intended for the broader electronic packaging and manufacturing community including: manufacturing engineers, packaging development engineers, as well as engineers and researchers in high reliability industries.

Leseprobe

Table of Contents

COVER

TITLE PAGE

LIST OF CONTRIBUTORS

INTRODUCTION

1 A PREDICTIVE MODEL FOR WHISKER FORMATION BASED ON LOCAL MICROSTRUCTURE AND GRAIN BOUNDARY PROPERTIES

1.1 INTRODUCTION

1.2 CHARACTERISTICS OF WHISKER AND HILLOCK GROWTH FROM SURFACE GRAINS

1.3 SUMMARY AND RECOMMENDATIONS

ACKNOWLEDGMENTS

REFERENCES

2 MAJOR DRIVING FORCES AND GROWTH MECHANISMS FOR TIN WHISKERS

2.1 INTRODUCTION

2.2 UNDERSTANDING THE MECHANISMS BEHIND IMC-INDUCED STRESS EVOLUTION AND WHISKER GROWTH

2.3 RELATION OF STRESS TO WHISKER GROWTH

2.4 CONCLUSIONS

ACKNOWLEDGMENTS

REFERENCES

3 APPROACHES OF MODELING AND SIMULATION OF STRESSES IN Sn FINISHES

3.1 INTRODUCTION

3.2 CONSTITUTIVE MODEL

3.3 STRAIN ENERGY DENSITY

3.4 GRAIN ORIENTATION

3.5 FINITE ELEMENT MODELING OF TRIPLE-GRAIN JUNCTION

3.6 FINITE ELEMENT MODELING OF S FINISH WITH MULTIPLE GRAINS

REFERENCES

4 PROPERTIES AND WHISKER FORMATION BEHAVIOR OF TIN-BASED ALLOY FINISHES

4.1 INTRODUCTION

4.2 GENERAL PROPERTIES OF TIN-BASED ALLOY FINISHES (ASAO NISHIMURA)

4.3 EFFECT OF ALLOYING ELEMENTS ON WHISKER FORMATION AND MITIGATION (ASAO NISHIMURA)

4.4 DEPENDENCE OF WHISKER PROPENSITY OF MATTE TIN–COPPER FINISH ON COPPER LEAD-FRAME MATERIAL (TAKAHIKO KATO)

4.5 CONCLUSIONS

ACKNOWLEDGMENTS

REFERENCES

5 CHARACTERIZATION TECHNIQUES FOR FILM CHARACTERISTICS

5.1 INTRODUCTION

5.2 TEM (TAKAHIKO KATO)

5.3 SEM (YUKIKO MIZUGUCHI)

5.4 EBSD (YUKIKO MIZUGUCHI)

5.5 CONCLUSIONS

ACKNOWLEDGMENTS

REFERENCES

6 OVERVIEW OF WHISKER-MITIGATION STRATEGIES FOR HIGH-RELIABILITY ELECTRONIC SYSTEMS

6.1 OVERVIEW OF TIN WHISKER RISK MANAGEMENT

6.2 DETAILS OF TIN WHISKER MITIGATION

6.3 MANAGING TIN WHISKER RISKS AT THE SYSTEM LEVEL

6.4 CONTROL OF SUBCONTRACTORS AND SUPPLIERS

6.5 CONCLUSIONS

REFERENCES

7 QUANTITATIVE ASSESSMENT OF STRESS RELAXATION IN TIN FILMS BY THE FORMATION OF WHISKERS, HILLOCKS, AND OTHER SURFACE DEFECTS

7.1 INTRODUCTION

7.2 SURFACE-DEFECT CLASSIFICATION AND MEASUREMENT METHOD

7.3 PREPARATION AND STORAGE CONDITIONS OF ELECTROPLATED FILMS ON SUBSTRATES

7.4 SURFACE DEFECT FORMATION AS A FUNCTION OF TIN FILM TYPE, SUBSTRATE, AND STORAGE CONDITION

7.5 CONCLUSIONS

APPENDIX

ACKNOWLEDGMENTS

REFERENCES

8 BOARD REFLOW PROCESSES AND THEIR EFFECT ON TIN WHISKER GROWTH

8.1 INTRODUCTION

8.2 THE EFFECT OF REFLOWED COMPONENTS ON TIN WHISKER GROWTH IN TERMS OF GRAIN SIZE AND GRAIN ORIENTATION DISTRIBUTION

8.3 REFLOW PROFILES AND THE EFFECT ON TIN WHISKER GROWTH

8.4 INFLUENCE OF REFLOW ATMOSPHERE AND FLUX ON TIN WHISKER GROWTH

8.5 EFFECT OF SOLDER PASTE VOLUME ON COMPONENT TIN WHISKER GROWTH DURING ELECTRONICS ASSEMBLY

8.6 CONCLUSIONS

ACKNOWLEDGMENTS

REFERENCES

9 MECHANICALLY INDUCED TIN WHISKERS