A High Performance Power Package for Wide Bandgap Semiconductors Using Novel Wire Bondless Power Interconnections

Abstract

Silicon carbide (SiC) wide bandgap semiconductor power device technologies offer improved electrical and thermal performance over silicon in high performance power electronic applications, such as hybrid or fully electric vehicles, aerospace, solar inverters, and advanced military systems. However, current packaging limitations make it difficult to operate these devices to their full potential. One such limitation includes die interconnections, which are traditionally made using large diameter aluminum wire bonds. This discussion introduces an innovative wire bondless interconnect technique for power packaging called PowerStep. This approach includes a precision etched metal tab with raised regions matching the size and location of device terminals and trenches to accommodate critical features on devices such as passivated surfaces. The tab offers a low profile, low inductance, low resistance, high electrical and thermal conductivity, and mechanically rugged interconnection solution. PowerStep has been implemented to facilitate a single-step interconnection method for a 600 to 1700 V SiC electronics package, replacing wire bonds which are connected one at a time. In addition, a key element of this package is the absence of a baseplate, resulting in lower weight, volume, and cost, as well as reduced manufacturing complexity. The electrical, thermal, and mechanical characteristics of PowerStep interconnections are analyzed and compared to conventional aluminum wire bonds to demonstrate the advantages of wire bondless interconnections coupled with wide bandgap devices. The low parasitics and junction-to-case thermal resistance of the package combined with PowerStep interconnects capture the high performance of SiC for power applications.