5.1.1 Scope

What drives the end-use market are the continued convergence of computing, communication, and entertainment as well as the relentless growth of the wireless, portable, handheld digital electronics and optoelectronics. On the ever-changing technology landscape, the industry has responded and will continue to respond to competitive demands in the global marketplace. New electronic gadgets will be featured with increasingly higher functionality, further simplicity, lower cost, and greater operational ease. What has transpired from these market demands is continued technological innovation and an ever-shortening product life cycle. Environment-friendly manufacturing and the delivery of environmentally benign end-use products that are ultimately safe at the end of the product life cycle will become essential to technology-business competitiveness. This is a continuing challenge to the industry. Solder has served as the interconnecting material for all three levels of connections: die, package, and board assembly. In addition, tin/lead solder is commonly used as a surface coating for component leads and PCB surface finishes. In addition to solder materials, the process used to form solder joints to accomplish the vital function of electrical, thermal, and mechanical linkages between two metallic surfaces is equally important.

This chapter addresses solder technologies in both material and process aspects for electronic packaging and assembly. Considering the established role of lead (Pb) and the demand in Pb-free materials, solder can be classified as either lead-containing or lead-free. In light of the global environmental commitment, this chapter will also cover Pb-free...