Advanced DBC (direct bonded copper) substrates for high power and high voltage electronics

Direct bond copper (DBC) substrates have been proven for many years as an excellent solution for electrical isolation and thermal management of high power semiconductor modules. The advantages of DBC-substrates are high current carrying capability due to thick copper metallization and a thermal expansion close to that of silicon at the copper surface due to high bond strength of copper to ceramic. The integration of this DBC substrate to a liquid cold plate made by the DBC process has made thermal resistances in the range of 30mK/W possible for a wide range of power applications. The main exception is in the case of high voltages (3 kV to 7 kV) where the partial discharge of typical DBC substrates makes them unacceptable. Increasing requirements for thermal performance and partial discharge free behavior of high power modules have driven research to further improve DBC substrates and the thermal performance available to high voltage applications. This paper will present recent developments of partial discharge free and liquid cooled substrates.