The breakdown of Anand constitutive model in life prediction of microscale BGA structure Sn–3.0Ag–0.5Cu joints stressed with electric current

This study investigates shear fatigue and fracture behavior of ball grid array (BGA) structure joints stressed with electric current. The results indicate that electric current weakens shear fatigue resistance of joints, and a lower shear fatigue life is obtained at a higher current density. While, the Anand constitutive model without considering the influence of elctric current is not suitable for predicting shear fatigue life of joints stressed with electric current. Moreover, at low current densities, the shear fatigue cracks propagate in solder matrix, and present an arc-shape path, which is mainly caused by concentration of plastic strain energy; interfacial fracture occurs at high current densities, which is due to strain mismatch between the solder/intermetallic compound (IMC) layer interface.