Research Status and Progress of Lead-Free Solder in Electronic Packaging

Pb in traditional brazing materials Sn-Pb is highly toxic, and leaded brazing materials have been gradually banned in order to minimize the hazards. Research on lead-free solder has made great progress in the past decades, among which SAC alloys are the most representative. SAC has gained wide attention and research because of its relatively good performance, this paper analyzes the performance of SAC alloys with different compositions and alloys doped with different elements, and gives an overview of the latest research on SAC brazing materials in recent years. Due to the problem of the high melting temperature of SAC braze in the field of complex architecture packaging, this paper also classifies and summarizes the low-temperature brazes proposed to solve the high melting temperature of SAC, analyzes the advantages and shortcomings of two kinds of brazes, Sn-based and In-based, and lists the ones that have been previously doped with different elements in different systems, and discusses the possible directions of future research.