Effects of Ga addition on microstructure and properties of Sn-0.5Ag-0.7Cu solder

The effects of rare element Ga on solderability, microstructure, and mechanical properties of Sn-0.5Ag-0.7Cu lead-free solder were investigated. The experimental results show that Ga plays a positive role in improving the wettability and the microstructure of the solder. When the content of Ga is at 0.5 wt%, the grain size of the solder is smaller and the shear force is enhanced greatly. It is also found that the thickness of the IMCs at the solder/Cu interface is reduced with proper addition of Ga. The increase of mechanical properties may be related to the refining of IMCs of the solder due to Ga addition.