Effect of loading rate on the shear performance and fracture behavior of micro-scale BGA structure Cu/Sn–3.0Ag–0.5Cu/Cu joints under coupled electromechanical loads

In this study, the shear performance and fracture behavior of micro-scale BGA structure Cu/Sn–3.0Ag–0.5Cu/Cu joints under electro-mechanically coupled loads with different loading rates (from 0.1 N/min to 1 N/min) and current densities (6.0×103 A/cm2, 8.0×103 A/cm2 and 1.0×104 A/cm2) have been investigated. The results show that shear strength of joints increases with the increase of loading rate at various current densities, and the relationship between the current density and the increasing rate of shear strength can be fitted by the Boltzmann function. In addition, for joints under high-density current stressing with low loading rate, fracture is prone to occur at the solder/IMC interface by a brittle fracture mode. While for joints under low-density current stressing with high loading rate, fracture tends to happen in the solder matrix by a ductile fracture mode.