The Recrystallization of Microelectronic Lead-Free Solders

Abstract

In Sn-2 mass%Ag-0.5 mass%Cu solder alloy, recrystallization was induced by thermal cycles and the homogenized effect of thermal aging promoted the vibration resistance. Due to the inner stress induced by thermal cycles, the thermal cycle specimen not only possessed a finer structure but also a large number of grain boundaries that were able to increase the vibration life. During vibration, dynamic recrystallization (DRX) was able to occur. In addition, DRX and grain growth had an obvious tendency to increase as the tensile strain rate was increased in the Sn-1 mass%Ag-0.5 mass%Cu solder alloy with a high β-Sn content. Also, high temperatures and plastic deformation had a significant influence on the recrystallization of the solders.