Mechanical properties and shear strength of Sn-3.5Ag-Bi solder alloys

Abstract

Mechanical properties and ball shear strength of Sn-3.5Ag-Bi were investigated with Bi addition of 0-9 mass%. Solder characteristics of Sn-3.5Ag-Bi were improved with Bi addition to decrease the melting temperature, to promote wetting to Cu and Ni substrates, and to increase the tensile strength and fracture energy. Shear strength of Sn-3.5Ag-Bi solder bumps increased with Bi addition up to 5 mass%, and was kept almost unchanged with further increase of Bi addition. Shear strength exhibited a parabolic relationship with the tensile fracture energy of the solder alloys.