Failure Analysis and Improvement for High Power Single-Phase Module

The failure mechanism of the single-phase power module for three-phase converter applications with high output power is investigated. It illustrates that the higher current density on the near-terminal side of the power device, along with the abreast bonding that induces thermal coupling at the second footprints of bond wires, together result in the failure of the power device in the module. Then, an improved bonding method by redistributing the bond wires is proposed to solve the reliability problem. The bond wires are staggerly soldered on the surface of the device, avoiding the second footprints from listing in a line to reduce the thermal accumulation. The simulation performed by TCAD ANSYS shows that the junction temperature (T j ) can be effectively decreased through this way. A practical experiment is also carried out to verify the availability of the optimized bonding method, which demonstrates that the improved method can decrease the T j of the device by 17 °C under 65A operating current.