Thermal grease pump-out visualizing system for power modules using 3D digital image correlation method

Inhalt:
Thermal grease pump-out phenomenon leads to an increase in the thermal resistance of power device packages, resulting in failures such as thermal runaway. The mechanism of this phenomenon has not been sufficiently analyzed from the viewpoint of monitoring the grease distribution at the base plate–heatsink interface. We propose a system to analyze the pump-out phenomenon of power devices using a displacement measurement technique through 3D digital image correlation (DIC). The system is designed to calculate the displacement of the device and visualize the change in the distribution of the thermal grease. The system was demonstrated on two types of power devices: an Econo-dual type power module and a transfer-molded intelligent power module.