Wire-bond contact degradation modeling for remaining useful lifetime prognosis of IGBT power modules

Reliability of power electronic equipment can be enhanced with the ability to predict its health state to avoid damage and permit making necessary maintenance. In this paper, an analytical physics of failure model is built that describes the contact resistance between wire-bonds and pad-metallization in an IGBT semiconductor device. On one hand, this model is based on the theory of the electrical contact resistance and the other hand on the spread of the current from the contact to the aluminum film. When contact degradations occur, the model can relate the crack propagation in the wire-bond interconnection to the collector-emitter voltage (VCE) and may allow identifying the health of the device. If the voltage is measured during actual operation, the length of the contact radius can be estimated and crack propagation rate can be calculated and used to predict the remaining useful life. The approach is tested with experimental accelerated aging tests.