Press-pack IGBTs are increasing their market-share, especially for traction
applications. As packaging performance is a key factor for a successful pr
oduct, there is a great interest in defining optimal solutions in terms of
geometry, materials and mechanical loading. To support IGBT reliability ass
essment we developed a testing rig for accelerated testing of a single chip
under controlled pressure conditions. In parallel, we created a thermomech
anical simulation of the chip/testing rig assembly for the determination of
internal stresses and strains due to actual operation. Test results and pr
eliminary 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. (C) 1999 Elsevier
Science Ltd. All rights reserved.