Transient Electrical-Thermal-Mechanical Coupling Model and Short-Circuit Failure Analysis of Wire-Bonded IGBT Module

The short-circuit (SC) failure of wire-bonded IGBT module (WB-IGBT) was investigated by combining testing and transient finite element (FE) simulation. First, the SC tests were conducted to 1.2-kV/75-A WB-IGBTs, and the characteristic parameters variations during the SC failure process were obtained. The failed modules were inspected by scanning electron microscopy (SEM). Second, the transient electrical-thermal-mechanical (ETM) coupling FE model for WB-IGBT was proposed, and the SC failure process was simulated. The weak points and failure mechanism were analyzed. Third, the effects of the metallization layer thickness and the bonding wires radius on the stress at the bonding points were simulated and analyzed. The results indicated that the bonding wires lifted off due to the high stress caused by the high SC current. Increasing the metallization layer thickness as well as the bonding wires radius helped to reduce the stress at the bonding points.