Low cycle fatigue of an interface between a substrate and molding resin in a power module

The demand for power modules is increasing year by year due to increases in the number of electric vehicles, renewable energy plants etc. The new generation of power modules are made of SiC, GaN and Ga
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O
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because of their wide band-gap. These semiconductors can be used under higher temperature than Si, and packaging materials like molding resin, die-attaching materials etc., that can withstand high temperatures, are being developed in many countries. The material strength of an interface between molding resin and a metallic substrate is one of the most important topics for the reliability of power modules. Thermal cycle testing is a popular method to evaluate the reliability of electronic packaging including power modules, but it requires a long testing time. To reduce the testing times of thermal cycle tests, we need to elucidate the crack extension law of the interface. We performed mechanical fatigue tests, and investigated the crack extension law of the interface under low-cycle fatigue.