Lead-free Solder Process Development

JASBIR BATH is the owner of Bath Technical Consultancy LLC in Fremont, California. He has over fifteen years' experience in research, design, development, and implementation in the areas of soldering, surface mount, and packaging technologies working for companies including Flextronics International/Solectron Corporation and ITRI (International Tin Research Institute). Bath has been chair of various iNEMI lead-free consortia involving OEMs, EMS, and component and material supplier companies on alloy selection, assembly, and rework.

CAROL A. HANDWERKER is the Reinhardt Schuhmann Jr. Professor of Materials Engineering at Purdue University, Indiana. Previously, she was chief of the Metallurgy Division at the National Institute of Standards and Technology (NIST), where she participated in the NCMS (National Center for Manufacturing Sciences) Lead-Free Solder Project and co-chaired the iNEMI Lead-Free Alloy Selection Team. Dr. Handwerker is currently active on the iNEMI Technical, Research, and Environmental Leadership Steering Committees, as well as a participant in a range of iNEMI project teams.

Preface.

Introduction.

Contributors.

1. Regulatory and Voluntary Drivers for Environmental Improvement: Hazardous Substances, Lifecycle Design and End of Life (John Hawley).

1.1 Introduction.

1.2 Substances of Environmental Concern.

1.3 Design for Environment/Energy Efficiency.

1.4 Recycling and Take-back.

1.5 Summary.

1.6 References.

2. Lead-free Surface Mount Technology (Jasbir Bath, Jennifer Nguyen and Sundar Sethuraman).

2.1 Introduction.

2.2 No-clean and Water-soluble Lead-free Pastes.

2.3 Solder Paste Handling.

2.4 Board and Stencil Design.

2.5 Screen Printing and Printability of Lead-free Solder Pastes.

2.6 Paste inspection.

2.7 Component Placement (Paste Tackiness).

2.8 Reflow Soldering and the Reflow Profile.

2.9 Effect of Nitrogen versus Air Atmosphere during Lead-free Reflow.

2.10 Head-in-Pillow Component Soldering Defect.

2.11 Solder Joint Visual Inspection.

2.12 AOI (Automated Optical Inspection).

2.13 X-ray Inspection.

2.14 ICT/Functional Testing.

2.15 Conclusions.

2.16 Future Work.

2.17 Acknowledgements.

2.18 References.

3. Lead-free Wave Soldering (Dennis Barbini and Jasbir Bath).

3.0 Introduction.

3.1 Wave soldering process boundaries.

3.2 Soldering temperatures on the chip and main soldering waves.

3.3 Alloys for Lead-free Wave Soldering.

3.4 The function of nitrogen in wave soldering.

3.5 The effect of PCB Design on wave solder joint formation.

3.6 Standards related to wave soldering.

3.7 Conclusions.

3.8 Future work.

3.9 Acknowledgements.

3.10 References.

4. Lead-free Rework (Alan Donaldson).

4.1 Introduction.

4.2 Surface Mount Technology (SMT) Hand Soldering/Touch-up.

4.3 BGA/CSP Rework.

4.4 BGA Socket Rework.

4.5 X-ray.

4.6 Through-hole Hand Soldering Rework.

4.7 Through-hole Mini-pot/Solder Fountain Rework.

4.8 Best Practices and Rework Equipment Calibrations.

4.9 Conclusions.

4.10 Future Work.

4.11 References.

5 Lead-Free Alloys for BGA/CSP Components (Gregory A. Henshall).

5.1 Introduction.

5.2 Overview of New Lead-Free Alloys.

5.3 Benefits of New Alloys for BGAs and CSPs.

5.4 Technical Concerns .

5.5 Management of New Alloys.

5.6 Future Work.

5.7 Summary and Conclusions.

5.8 Acknowledgements.

5.9 References.

6 Growth Mechanisms and Mitigation Strategies of Tin Whisker Growth (Peng Su).

6.1 Introduction.

6.2 Role of stress in whisker growth.

6.3 Understanding standard acceleration tests.

6.4 Plating process optimization and other mitigation strategies.

6.5 Whisker growth on board-mounted components.

6.6 Summary.

6.7 References.

7. Testability of Lead-Free Printed Circuit Assemblies (Rosa D.Reinosa and Aileen M. Allen).

7.1 Introduction.

7.2 Contact Repeatability of Lead-Free Boards.

7.3 Probe Wear and Contamination.

7.4 Board Flexure.

7.5 Conclusions.

7.6 Acknowledgments.

7.7 References.

8. Board-Level Solder Joint Reliability of High Performance Computers under Mechanical Loading (Keith Newman).

8.1 Introduction.

8.2 Establishing PWB Strain Limits for Manufacturing.

8.3. SMT Component Fracture Strength Characterization.

8.4 PWB Fracture Strength Characterization.

8.5 PWB Strain Characterization.

8.6. Solder Joint Fracture Prediction – Modeling.

8.7. Fracture Strength Optimization.

8.8 Conclusions.

8.9 Acknowledgments.

8.10 References.

9. Lead-Free Reliability in Aerospace/Military Environments (Thomas A. Woodrow and Jasbir Bath).

9.1 Introduction.

9.2 Aerospace/Military Consortia.

9.3 Lead-Free Control Plans for Aerospace/Military Electronics.

9.4 Aerospace/Military Lead-Free Reliability Concerns.

9.5 Summary and Conclusions.

9.6 References.

10. Lead-Free Reliability in Automotive Environments (Richard D. Parke).

10.1 Introduction to Electronics in Automotive Environments.

10.2 Performance Risks and Issues.

10.3 Legislation Driving Lead-Free Automotive Electronics.

10.4 Reliability Requirements for Automotive Environments.

10.5 Failure Modes of Lead-free Joints.

10.6 Impact to Lead-free Component Procurement and Management.

10.7 Change versus Risks.

10.8 Summary and Conclusions.

References.

Index.

The New copy of this book will include any supplemental materials advertised. Please check the title of the book to determine if it should include any access cards, study guides, lab manuals, CDs, etc.

The Used, Rental and eBook copies of this book are not guaranteed to include any supplemental materials. Typically, only the book itself is included. This is true even if the title states it includes any access cards, study guides, lab manuals, CDs, etc.