Pin electrical resistance welding capability and verification of new TO-247 PLUS discrete package

Abstract:
Discrete semiconductors connected in parallel for high-power density solutions and design scalability have been adopted in many application scenarios. Key challenges to these solutions are increasing production efficiency and high currentcarrying capacity, and reducing the heat dissipation at the pins caused by heavy load current with liquid cooling. Jointly connecting discrete pins and copper busbars is one effective way of tackling these issues. This is done by resistance-welding technology. Owing to the different melting points on package surfaces, the metal-to-metal welding profile must be qualified for the discrete package and the relevant production process. This paper demonstrates the resistance welding capability of the pins in the TO-247 PLUS discrete package, and validates the reliable joint connection between the discrete pins and the copper busbar to flow the current through. It also includes an analysis of the cross-section and intermetallic compound (IMC) layer that was further enhanced to achieve the qualified welding profile of this new package.