Diffusion Soldering for the High-temperature Packaging of Power Electronics

Abstract

With advances in the new generation semiconductor materials and ever-increasing requirements for reliable power electronic modules at elevated temperatures, a major limitation is the lack of qualified high-temperature device-level packaging. This work gives an overview of optimization and evaluation of Cu-Sn based Transient Liquid Phase Soldering (TLPS), a variant of diffusion soldering to implement as a high-temperature die-attach technique for power electronics production with high level of flexibility and customization. The TLPS interconnects with enriched ƞ-Cu6Sn5 Intermetallic phase bondline were realized successfully with optimized temperature profiles. A comprehensive analysis was performed on the process-related issues of voids for the selected soldering technique and warpage for components of varying dimensions and metallizations. Further the quality of the produced joints was evaluated by thermo-mechanical loading followed by the characterization of thermal and mechanical stability. The applicability is checked with product and technology case studies and an outlook is given with comparison of the investigated production concepts.