In Situ Degradation Monitoring Methods during Lifetime Testing of Power Electronic Modules

Within the scope of this work three in-situ degradation monitoring methods are presented. The methods are suitable for the detection of degradations in power electronic modules during active power cycling test without interrupting the test itself. A comparison of the results is illustrated by conducting all three techniques during the lifetime testing of a power electronic module at the same time. In sum, electrical, electrothermal, thermal and thermomechanical parameters were evaluated. From the observations, we conclude that the primary failure mechanism of a novel die-top interconnect technology for power modules is the crack propagation in the Al-metallisation of the semiconductor. Cross-sectional images of the samples were prepared to confirm the previously given evidence of the failure. Furthermore a lifetime model was established for this assembly technology. Finally, a comparison of the advantages and limitations of the conducted degradation monitoring techniques will be presented.