SUMMARY

Recent advances in technology in addition to policies across the globe enacted to counter the environmental impact of climate change have engendered a push for more renewable and sustainable sources of power, including the electrification of automotive systems. Power electronics play a key role in these systems, managing large heat fluxes, high power densities and high voltage switching. However, as devices become smaller and operating temperatures increase, combating system failure due to over-temperature or heat damage becomes critical. To address these concerns, a power package design has been developed that brings the thermal management features closer to the device by bonding the dielectric substrate directly to a heat sink of similar coefficient of thermal expansion (CTE) via a transient liquid phase (TLP) bond, enhancing the thermo-mechanical reliability of the package and eliminating multiple material layers, thereby decreasing the thermal resistance of the assembly. In order to thoroughly investigate the composition of the bond and assess the TLP technique in bonding commercial substrates to low CTE cold plates as a packaging alternative, experimental methods on a variety of AlN, Al and Cu substrates TLP bonded to AlSiC heat sinks are conducted and the results validated through numerical modeling. A complete analysis of the bond material composition, microstructure, intermetallic phases and the impact of processing parameters on solid-state diffusion in the binary system is provided. Subsequently, an investigation into the mechanical and thermo-mechanical characteristics of various Cu-Al composites fabricated through a similar TLP bonding process is presented. Finally, potential approaches for manufacturing a metal circuit layer on the AlN dielectric ceramic using additive manufacturing methods are explored, supporting the development of a functional power package with enhanced electrical conductivity for electronic devices.