Shear deformation behavior of a Sn–3Ag–0.5Cu single solder ball at intermediate strain rates

Shear tests were conducted to evaluate the mechanical behavior of miniature single solder ball joints. The tests were carried out at room temperature under displacement control mode and various displacement rates (2.16–0.019 mm/s) using a miniaturized testing machine with an attached piezo-electric actuator. The mean shear stress was estimated on the basis of the mean cross-section area rather than the minimum cross-section area. The shear fracture strength of the present solder ball joints generally increased as the shear strain rate increased due to the sensitivity of the bulk solder strength to the strain rate. The relationship between strain rate and stress of the current shear tests is consistent with findings from other experimental techniques on the same solder alloy. The unloading shear fracture toughness was found to increase as the shear strain rate increased. The unloading shear fracture toughness is generally consistent with the amount of bulk solder on the fractured surface.