In-service reliability assessment of solder interconnect in power electronics modules

Power electronic modules (PEMs) are widely used in aerospace and automotive applications where high reliability is essential. Solder joint fatigue is one of the major failure mechanisms in PEMs, a reliability assessment method for this failure mechanism is presented in this paper. Differing from the traditional reliability prediction methods, this approach allows the reliability performance of PEMs to be assessed in real time. Firstly, a compact thermo-mechanical model of the solder interconnect was constructed using both high-fidelity and reduced order computer modeling, it was then integrated with the lifetime model of the solder joint. Secondly, a real time compact electro-thermal model was developed using both experimental and computer modeling techniques, and was used to predict the temperatures of device junctions, interfaces etc. that cannot ordinarily be measured during service. Using the above two compact models the lifetime consumption of the solder interconnect in PEMs under service conditions can be calculated based on the linear damage rule. A demonstration of this reliability assessment method is also given at the end of this paper