Lead Free Electronic Solders

Even though the effect of lead contamination on human health has been known for decades, very little attention has been paid to lead-based solders used in electronics until recently. This comprehensive book examines all the important issues associated with lead-free electronic solder. It collects the work of researchers recognized for their significant scientific contributions in the area.

The book is important because it reflects a trend, especially in microelectronics manufacture toward recyclability. Europe and Asia are moving towards legislation to ban the use of lead in solders and public demand in the US will likely have the same result. Producers of solders and manufacturers who use them will have to invent and employ suitable substitutes and A Guide to Lead-free Solders will show them how to do so.

This unique book provides an up-to-date overview of the concepts behind lead-free soldering techniques. Readers will find a description of the physical and mechanical properties of lead-free solders, in addition to lead-free electronics and solder alloys. Additional topics covered include the reliability of lead-free soldering, tin whiskering and electromigration, in addition to emerging technologies and research.

This book provides some of the most advanced research observations and in-depth knowledge behind lead-free soldering. Readers will find a description of different cutting-edge techniques used for improving the reliability of interconnects manufacturing. Some of the most unconventional topics covered in this book include solder joint formation for microelectronic devices at room temperature and the possibility of soldering ceramic materials, which is limited due to the poor wettability of ceramic substrates with commercial solders following classical soldering techniques. We also discuss the possibilities of nanoscale preparation of solder joints for bringing down the processing temperature so that it does not affect the packaging technologies. Readers will find that precise, systematic discussion of solder joint formation and its interfacial characterization has been depicted for each technique used in different chapters. This book is of interest to both fundamental researchers and also to practicing scientists and will prove invaluable to all those working in industry and academia.

Providing a viable alternative to lead-based solders is a major research thrust for the electrical and electronics industries - whilst mechanically compliant lead-based solders have been widely used in the electronic interconnects, the risks to human health and to the environment are too great to allow continued widescale usage. Lead-free Solders: Materials Reliability for Electronics chronicles the search for reliable drop-in lead-free alternatives and covers: Phase diagrams and alloy development Effect of minor alloying additions Composite approaches including nanoscale reinforcements Mechanical issues affecting reliability Reliability under impact loading Thermomechanical fatigue Chemical issues affecting reliability Whisker growth Electromigration Thermomigration Presenting a comprehensive understanding of the current state of lead-free electronic interconnects research, this book approaches the ongoing research from fundamental, applied and manufacturing perspectives to provide a balanced view of the progress made and the requirements which still have to be met.

Solders have given the designer of modern consumer, commercial, and military electronic systems a remarkable flexibility to interconnect electronic components. The properties of solder have facilitated broad assembly choices that have fueled creative applications to advance technology. Solder is the electrical and me chanical "glue" of electronic assemblies. This pervasive dependency on solder has stimulated new interest in applica tions as well as a more concerted effort to better understand materials properties. We need not look far to see solder being used to interconnect ever finer geo metries. Assembly of micropassive discrete devices that are hardly visible to the unaided eye, of silicon chips directly to ceramic and plastic substrates, and of very fine peripheral leaded packages constitute a few of solder's uses. There has been a marked increase in university research related to solder. New electronic packaging centers stimulate applications, and materials engineering and science departments have demonstrated a new vigor to improve both the materials and our understanding of them. Industrial research and development continues to stimulate new application, and refreshing new packaging ideas are emerging. New handbooks have been published to help both the neophyte and seasoned packaging engineer.