Trends in Power Module Packaging and Impact of Wide Bandgap Semiconductors

Abstract:
The last decade has brought severe changes to power module packaging and die attach technologies. While the industrial power module market has been driven by strong standardization and cost reduction measures, we have seen an unprecedented market growth in the automotive world with highly advanced packaging concepts. The ever-increasing demand for highest power densities and reliability improvements in automotive applications accelerated new die attach technologies such as sintering, bond buffer, Cu bonds and top side flex foil in combination with high performance substrates, module direct and dual side cooling concepts as well as large transfer molded structures. Wide bandgap semiconductors in particular SiC devices made their push through in many demanding markets like solar, charging infrastructure and automotive. Almost every car with 800V battery is powered by SiC MOSFET modules with up to 700A current ratings. This requires paralleling of many SiC MOSFET chips since the dies are still small in comparison to Si IGBTs. Many dies in parallel in combination with fast switching transients requires special attention to the module internal layout with high requirements towards symmetrical and low inductance power and auxiliary gate structures including magnetic coupling effects. The authors will give an overview of state-of-the-art die attach technologies and power module packaging including an outlook on future trends with special focus on power module layout and electrical properties driven by wide bandgap semiconductors.