A stress model for multiobjective design optimization of a power electronic module

摘要

One of the most common failure mechanisms in power electronic modules is fatigue of the die attach due to shear stresses created by a mismatch in the thermal expansion of the die and the substrate. This paper presents a shear stress model in thedie attach that incorporates viscoplastic stress components that become more important at the elevated temperatures in power electronic modules. The paper also describes a multiobjective design optimization approach utilizing a genetic algorithm forminimizing the chance of module failure, not only by die attach fatigue, but also by other competing failure mechanisms such as overheating of the chip, die fatigue, and substrate fatigue. It is shown that a successful power electronic module (PEM) design must balance the tendencies to fail by these competing failure mechanisms. Several tradeoff solutions in PEM design are presented for different size and material choices for a PEM design.