A Conceptional Study towards Developing a Novel Copper Top-Side Interconnection Process in Power Electronics using Additive Manufacturing

With increasing power densities for high performance power electronics copper is a common material chosen for the top-side interconnection, since improvements in the die attachment processes for higher junction temperatures shifted the bottleneck in reliability to the top-side interconnection. Many copper-based interconnecting technologies are currently under development or even in application, yet none are additively manufactured. Laser powder bed fusion (LPBF) in combination with thermo-mechanical Cu-buffers on the top-side of the semiconductor device could be a possible interconnection technology with high geometric freedom which allows for the application of generic design, biomimicry or tailored power modules. Prerequisite is the processing of metal powder on top of the semiconductor device with high energies while preserving the integrity and electrical properties of the same. This paper studies different power module technologies and the LPBF-process to acquire requirements and necessary modifications to enable additive manufacturing in power modules. These requirements are applied and consolidated into a theoretical roadmap for directly printed top-side interconnections. A proof-of-concept for the critical interface between the final metallization of the semiconductor device and simple laser fused structures concludes this study.