High Performance, Low-Cost IGBT Power Module Thermal Management for HEV/EV Applications

This proposal addresses a critical need to develop low cost packaging solutions to reduce size, weight, and increase performance in hybrid electric vehicle (HEV) and electric vehicle (EV) motor drive power electronics. IGBT (integrated gate bipolar transistor) and inverter/converter devices for HEV/EVs currently use silicon as the primary switching element where junction temperatures cannot exceed ~150C. Power modules operating in the harsh environment of an engine compartment must maintain acceptable junction temperatures and require large actively cooled heat sinks which add significant cost and weight to vehicles. MMCC proposes to advance IGBT power module packaging technology by demonstrating that Al2O3 and AlN dielectric substrates can be in-situ cast into lightweight CTE (coefficient of thermal expansion) matched copper graphite composite heat sinks together with the copper metallization layer that effectively becomes a direct bonded copper process (DBC). In addition to providing a low cost net shape casting, the proposed process will feature: 1) a CTE matched high thermal conductivity (2x that of current materials) copper graphite composite base plate; 2) capture a ceramic dielectric substrate, effectively creating a DBC dielectric and eliminating a high thermal impedance interface as well as a manufacturing process step; 3) capture cast-in cooling channels during pressure infiltration casting, thus eliminating a second high thermal impedance interface layer and providing for high efficiency cooling, and finally as an option, 4) enable the migration from Si to SiC IGBT semiconductors which can accommodate higher power and junction temperatures. Commercial Applications and Other Benefits: The proposed technology will be applied to hybrid electrical vehicles, plug-in hybrid electric vehicles and electrical powered vehicles as well as traction and utility vehicles. Other applications could be for RF power amplifiers for the telecommunications industry as well as advanced microwave and radar applications. This technology will increase the cooling capacity and enable the migration from Si to higher power capacity SiC and GaN semiconductors.