Power cycling on press-pack IGBTs: measurements and thermomechanicla simulation

摘要

Press-pack IGBTs are increasing their market-share, especially for traction appkicaitons. As packaging performance is a key factor for a successful product, there is a great interest in defining optimal solutioins in terms of geometry, materials and mechanical loading. To support IGBT reliability assessment we developed a testing rig for accelerated testing of a single chip under controlled pressure conditions. In parallel, we created a thermomechanicla simulation of the chip/testing rig assembly for the determination of internal stresses and strains due to actual operation. Test results and preliminary failure analysis following power cycling show the possibility of predicting the degradation according to different mechanisms induced by the combined effect of pressure and temperature fluctuation.