Simulation of crack propagation in solder layer of IGBT device under temperature shock by viscoplastic phase field method

Abstract

Insulated Gate Bipolar Transistor (IGBT) is a key device in power system. During its service, due to the mismatch of thermal expansion coefficients, cracking of the solder layer may result in reliability concerns. However, the thickness of the solder layer is generally only tens of microns, so it is challenging to study the dynamic crack propagation in the solder layer. In this study, the viscoplastic phase field method is combined with the Anand viscoplastic model commonly used in solder alloys to simulate the dynamic fracture of the IGBT solder layer during temperature shock test (TST). The simulation results are compared with the experimental results and the results are very close. In this paper, the effect of solder voids and solder inclination on crack propagation is studied by using phase field method. It is found that the presence of voids promotes crack propagation, and the crack propagation rate is faster on the thin side when the solder is tilted.