Microstructure and Tensile Properties of Sn-Ag-Cu-In-Sb Solder

Abstract

Microstructures and tensile properties at 233 K, 300 K and 398 K of Sn-3.0 mass%Ag-0.5 mass%Cu (SAC305) and Sn-Ag-Cu-In-Sb solder were investigated by using miniature size specimens with 0.5 mm diameter, which can reproduce the microstructure of the real solder joint. In this study, three kinds of Sn-Ag-Cu-In-Sb solder (SAC305-6.0 mass%In-1.0, 2.0 and 3.0 mass%Sb) were used. The microstructure of SAC305 consisted of a single crystal grain. On the other hand, the microstructures of Sn-Ag-Cu-In-Sb solder consisted of polycrystalline. The number of crystal grains per the cross section of SAC305-6.0In-1.0Sb was stably several tens or more. The tensile strength of Sn-Ag-Cu-In-Sb was improved approximately 2 times that of SAC305. Also, the variation in tensile strength of SAC305 at 233 K was large due to anisotropy of the crystal grain. In contrast, the variation in tensile strength of Sn-Ag-Cu-In-Sb at 233 K was lower than that of SAC305. In particular, that of SAC305-6.0In-1.0Sb was reduced to approximately a sixth of that of SAC305. It seems that the effect of anisotropy of the crystal grain is decreased by polycrystallization in SAC305-6.0In-1.0Sb.