Opportunities and Challenges of Pressure Contact Packaging for Wide Bandgap Power Modules

Conventional packaging technologies cannot facilitate full utilization of wide bandgap (WBG) power modules due to the parasitics of wire bonds and the thermal stresses in solder layers. Pressure contact technology is considered to be an effective approach to reduce stress and to make the assembly compact by replacing solder materials and wire bonds. This article reviews the state of the art of pressure contact packaging and discusses the advantages and limitations of various adopted methodologies. The challenges are revealed in detail in terms of die metallization, multiphysical design, stress distribution, and failures in pressure-based joints. In addition, potential future trends of pressure contact packaging toward different power levels and strategies to select appropriate technologies for different scenarios are discussed. This work aims to support designers in implementing pressure contacts in WBG power modules to fully exploit their advantages and to improve the reliability in thermal cycling.