PCB Embedding using Single-Switch-Pre-Packages as Modular Building Blocks

This paper presents a modular fabrication concept for printed circuit board embedded power semiconductors. The fabrication is done in a two step approach. First, the Single-Switch-Pre-Packages (SSPP) are built using standard embedding processes. Subsequently, full converters are fabricated by embedding of the SSPP as functional inlays into a PCB-power module. For optimal heat spreading, the semiconductor dies are silver sintered on a thick copper substrate. To exploit further the potential of the substrate, heat exchanger structures are chemically etched on it. Dielectric coolant serves as the cooling medium in this case. Laboratory demonstrators are built and characterization is performed as proof-of-concept. Thermal test indicates an junction to ambient thermal resistance of 0.43 K/W, compared to 0.8 K/W for reference module on a standard cold plate with water glycol. The hydraulic power and coolant temperature were identical for both cases.