Thickness Effect of Copper Clips on Power Module Packaging Design

The superior switching performance of SiC MOS-FETs compared to Si devices is limited by packaging-related issues. High electromagnetic parasitics which lead to high voltage overshoots, and higher power losses are the main challenges of high frequency operation. Hence, packaging design modification and optimisation are necessary to accommodate faster switching. Copper clips replacing the bonding wires show promising results in reducing stray inductances, while enhancing the current conduction and heat dissipation since the clip are in contact with a larger area of the semiconductor chip. Silver sintering instead of soldering further improves the electrothermal behaviour. This paper investigates numerically various thicknesses of the copper clips and their effect on double-sided silver sintering, half-bridge 1200V/400A SiC MOSFET power module. Moreover, the silver layer thickness is varied to reduce the maximum stresses on the chip - silver interface.