Guest Editorial - Recent Research Advances In Pb-free Solders

摘要

Owing to the widespread applications of Pb-free solders in the electronic packaging industry, processing, properties, and reliability of Pb-free solder joints in consumer products are attracting more interest and concern from both academia and technologists. Although solder technology is very old, it has the major advantage that it is simple. Solder joint is ubiquitous in the form of chip connection and board-level packaging. Through the application of a chemical flux and reflow in forming gas, high yields in mass production and good reliability can be achieved. At present, no other joining method in device packaging can achieve the same degree of packaging density, yield, and reliability.rnWhile ball grid array (BGA) solder balls for board-level packaging have already been Pb-free industry-wide since 2006, solder bumps for chip connection remain primarily in the realm of high-Pb and Sn-Pb eutectic up until now. In anticipation of tightening green regulations globally, the electronic packaging industry is, however, moving full steam as we speak towards Pb-free chip connection. Consequently, the industry is witnessing an unprecedented pace of innovation and fundamental research centering around the physics, chemistry, and materials science of Pb-free solders and their interactions with adjacent structural components, e.g., under bump metallurgy (UBM) on the device side and pad surface finish on the substrate side.