Numerical simulation of the intermetallic compound cracking in solder joint

The microcracking behavior of the IMC layer is investigated numerically, and the effect of the thickness of the IMC layer on the overall response and failure mode of the solder joint is studied using qualitative numerical simulations. The results show that the thicker IMC layer results in lower overall strength. When the IMC layer is thin, the microcracks tend to start at the valley of the rough solder/IMC interface and propagate across the root of the protruding Cu₆Sn₅ grains; when the IMC layer is thick, the microcracks tend to occur within the IMC layer. These predictions agree well with experimental observations.