Study on the characteristics of various dopants in Sn-1Ag-0.8Cu solder

Recently, the Sn-Ag-Cu system alloy has been widely used in the packaging (PKG) industry a replacement for conventional SnPb solders. The Sn-Ag-Cu system alloy was divided into two types, high Ag solder and low Ag solder composition, according to Ag content. Generally, high Ag solder, as Sn-3~4Ag-0.5Cu, showed good thermal cycle (TC) reliability because of excellent creep resistance and thermal fatigue reliability, but it showed poor drop impact reliability compared to SnPb solder or low Ag solder. Meanwhile, low Ag solder as Sn-0.3~1.2Ag-0.5Cu showed better drop shock reliability than high Ag solder, but it showed poorer TC reliability. These results mean that just a change in Ag content in the SAC alloy cannot simultaneously improve TC and drop impact reliability.