Bonding wire life prediction model of the power module under power cycling test

Abstract

Power modules have been applied in various electrical products, such as power supplies, AC/DC converters, and hybrid vehicles. During power cycling tests, the coefficient of thermal expansion mismatch (CTE) between the wire and chip may cause wire liftoff. This research aims to develop an approach for wire reliability assessment. A 3-D finite element (FE) model was established based on real test samples. Coupled electro-thermal and thermal-mechanical FE analyses were conducted to analyze the mechanical behavior of bonding wire under cyclic power loading. The temperature predicted by the FE analyses was consistent with the experimental data. Incremental plastic strain was not observed when the current loading was low. The concept of high cycle fatigue should be incorporated into the life prediction model for modules subjected to low current loadings. After the simulation results were validated with the experimental data, a model for the design of power modules was proposed.