A new SiC power module assembly based on silver sintering bonding

Driven by the need for more reliable die and substrate attachment in wide band gap power electronics, a new bonding process scheme of silver (Ag) sintering of large interfaces has been developed for silicon-carbide power MOSFETs, where the devices are placed before pre-drying (or pre-heating) the sintering Ag paste. Using the new wet placement process, a maximum shear strength (76 MPa) and minimum void fraction (0.02 %) can be achieved provided that the pre-heating temperature is 80 °C and the power devices are well positioned by a specially developed vacuum-assisted fixture. Applied on an STPak sub-module power device, it still showed full functionality after sintering at 230 °C, 15 MPa and 10 mins.