Numerical simulation of the wire bonding reliability of IGBT module under power cycling

As the demand of power converter for higher power density is increasing, bonding wire failure of IGBT module becomes more severe. Accordingly, it is of great significance to investigate the reliability of bonding wire under operating condition for improving the reliability of IGBT module. In this paper, the finite element model of IGBT module was established, and a two-step indirect coupling electro-thermal-mechanical analysis was conducted to evaluate the wire bonding reliability of IGBT module under the power cylcing. The thermal-mechanical analysis results indicate that the maximum equivalent plastic strain occurs at the corner of the bonded interface between the outermost bonding wire and the chip, where the cracks may initiate and then propagate along the interface, which is consistent with the observations of experimental results. It suggests that the outermost bonding wire is more likely to fail.