Reliability analysis and optimization of aluminum bonding wire for SiC power module with stacked substrates

The stacked substrate packaging technology is utilized to achieve a 3D power loop with ultra-low parasitic for the fast switching SiC device. However, this structure has different bonding wire geometry contrasting to the conventional module design, which will cause reliability problem for this new technology. This paper models and verifies the optimum bonding wire geometry parameters for stacked substrate packaging structure under accelerated temperature cycling simulation. The simulation results show that the bonding wire reliability will increase when the second welding point located at the center of the top DBC substrate as well as when top DBC copper layer thickness increases or ceramic layer thickness decrease. Moreover, smaller diameter bonding wire, higher bonding wire peak height and longer distance between two welding point will contribute to a better reliability.