Development of copper-copper bonding by ultrasonic welding for IGBT modules

In this paper, we present the copper-copper bonding technique by ultrasonic welding for the copper terminals of large current, high reliability IGBT modules. Investigated topics are joint strength indicated from joint microstructure, the effect of copper hardness on joint strength, the relationship between terminal bonding location and the damage to the insulator layer in the module structure, and reliability estimation of large IGBT modules with ultrasonic welding comparing with conventional soldering.