Thermo-Mechanical Design Considerations in 3D-Integrated SiC Power Device Package

Wide bandgap semiconductors, such as silicon carbide (SiC), have properties that allow them to surpass the performance of conventional silicon (Si) semiconductors in power electronic applications. Placing these wide bandgap devices in 3D-integrated packaging structures offers potential for significant power density increases as well. This paper addresses the thermo-mechanical design considerations in such a package containing a full bridge DC-DC converter with multifunctional heat sinks directly bonded to bare-die SiC MOSFET's, as well as additively manufactured transformer windings. This structure is accomplished by developing and incorporating innovative design practices with additive manufacturing technology and multi-functional elements that will serve combined mechanical, electrical, and thermal functions. The following critical elements of this innovative converter are highlighted: the demonstration of a syringe-printed transformer winding using nano-silver paste, and flip-chipped SiC switching devices bonded via Ag-In based transient liquid phase sintering (TLPS).