A novel chip joint method for high temperature operated SiC power modules

A novel chip joint method for bonding SiC power device chips with Al metallized electrodes has been developed for three-dimensional (3D) packaging. This method is a combination of Au stud bumping on an Al metallized electrode of a power chip and subsequent reflow soldering with Au-20Sn solder. The die shear strength of a Au-stud-bumped SiC power device chip bonded on a AlN/Cu/Ni(Au) substrate with Au-20Sn solder reached up to 83.67MPa, which was about 5 times higher than that of a Au-stud-bumped chip bonded with Pb90-Sn solder. After shear test, the assembly fractured at the solder/substrate interface rather than at the solder/chip interface. This indicates that an Al metallized electrode of a power chip can be solidly assembled to a AlN/Cu/Ni(Au) substrate by Au stud bumps and Au-20Sn eutectic solder. After being aged at 200degC for 300 hrs, the resistance change of the bonded chips with Au-stud bumps and Au-20Sn solder was less than 6%. This proposed chip joint method presents a novel approach for 3D packaging high temperature operated SiC power modules.