Packaging of high temperature 50 kW SiC motor drive modules for hybrid- electric vehicles

As the demand for hybrid- and fully-electric vehicles continues to rise, the requirements of the requisite power electronics systems (namely, power density, size, and weight) are rapidly surpassing the limits of current technology. As such, a large effort has been focused on the development of wide band gap semiconductor technology, such as Silicon Carbide (SiC), which promises benefits including higher current densities, higher voltage blocking capabilities, and operation at temperatures vastly exceeding silicon. In order to fully take advantage of these benefits, it is paramount that the entire system be designed to handle these elevated conditions. Arkansas Power Electronics International, Inc., in collaboration with the University of Arkansas and Rohm, Ltd., has developed a high-temperature (250+°C), high-performance 50kW integrated motor drive incorporating SiC-based switch technology, multi-chip module (MCM) gate driver, and high-temperature packaging techniques. This discussion presents the overall design of a 600V 180A fully functional single phase half-bridge module containing eight paralleled Rohm 30A SiC DMOSFETs per switch position. Specifically the high-temperature packaging of these systems is discussed in detail, including: power and driver substrates, base plate materials, transient liquid phase (TLP) die attach, wire bonds, passivation, and housing materials. The thermal performance of the system under power is also addressed, with key focus on reducing the thermal resistance of each layer Finally, the high-temperature electrical test results of the fabricated prototype systems are presented, followed by plans for future work.