Effects of Ga addition on microstructure and properties of Sn-0.3Ag-0.7Cu solder

The effect of Ga addition on the microstructure, mechanical properties and weldability of Sn-0.3Ag-0.7Cu (SAC0307) lead-free solder was investigated in this research. It shows that Ga addition has positive impact on refining the microstructure and improving wettability of SAC0307. When Ga addition in SAC0307 accounts for 0.6 wt%, the solder has smaller grain size, more uniform distribution of intermetallic compound (IMC), and higher sheer strength. The results also demonstrate that proper content of Ga could obviously decrease the thickness of IMC on the bond interface between solder and cooper pad. The improvement of mechanical properties of SAC0307 may be related to the refining of IMCs of the solder due to Ga addition.