Development of lead-free Sn-0.7Cu-Si₃N₄ composite solders

Lead based solder have been widely used before science have proven lead as one of the hazardous substances which can harm the environment and human health. With the banning usage of lead based solder as interconnect, various lead-free solders have been introduced and some of them are currently being widely used. However, none of them still can surpass the properties of a lead based solder, which keeps the researches on lead-free solder still going on and on. In this project, a new lead-free composite solder was developed by adding various amount of Si₃N₄ into Sn-0.7Cu solder via powder metallurgy route which consists of mixing compaction and sintering. Composite solder was used in order to enhance the properties of the conventional solder. The project was divided into two phases, where at Phase 1, the optimization of mixing, compaction and sintering were studied while at Phase 2, the composite solder were tested, analyzed and compared with the monolithic solder. Upon completion of both phases, the best amount of Si₃N₄ was added into Sn-0.7Cu will be proposed. Generally, the Sn-0.7Cu-Si₃N₄ composite solder showed improvement compared to the monolithic solder and it was finally decided that Sn-0.7Cu-0.5Si3N4 was the most preferable composite solder.