Silicon Interposer as a Substrate for Power Modules with High Power Density and Superior Thermal Performance

This paper presents a substrate technology for power modules based on a silicon interposer. The interposer is designed and processed with thick copper layers and high-aspect-ratio through-silicon vias (TSVs) [1], enabling its use in power applications. Components can be assembled on the substrate by means of conventional surface-mount technology (SMT) pick-and-place machines. Module encapsulation can then take place by molding of a desired molding compound. By applying the packaging technology to a power module design of a point-of-load buck converter for field programmable gate arrays (FPGAs) and server applications, and lead-frame packaging, the silicon substrate can achieve up to 25 % improvement in thermal performance compared to the laminate-substrate-based package [2]. That allows for higher power density and less derating for the same maximum allowable temperature on the application platform.