Effect of thermal-shearing cycling on Ag3Sn microstructural coarsening in SnAgCu solder

Microstructures of Ag3Sn particles, formed around Cu6Sn5 intermetallic compound (IMC) and in a lead-free solder (Sn3.5Ag0.5Cu), changes significantly under thermal-shearing cycling condition. In the solder, the coarsening kinetic of Ag3Sn particles was studied, which was correlated with stress-strain rate of the solder joints subjected to thermal-shearing treatments. Furthermore, the large Ag3Sn platelets surrounding Cu6Sn5 had obvious effect on the morphology and growth of Cu6Sn5 IMC. Formation mechanism of Ag3Sn particles during thermal-shearing cycling process was investigated.