Electro-Thermal-Mechanical Multiphysics Coupling Failure Analysis Based on Improved IGBT Dynamic Model

Failure of the power device can have a very large impact on the entire power circuit. IGBT as the main power device, ensuring its reliability becomes more and more important. In different environments, there will be large differences in the failure rate of IGBTs. Therefore, studying the failure mechanism of IGBT is of great significance to ensure the reliability of IGBT. Firstly, the IGBT dynamic model is constructed and the model is improved to correct the power consumption error. Then the IGBT finite element model is used to analyze the electro-thermal-force of different material layers, at the same time, the distribution of stress and temperature between different materials are analyzed. Finally, the JavaScript script is used to generate random defects of the solder layer, and the effects of different defects of the solder layer on the weakest part of the IGBT are studied, including voids, cracks, and solder layer falling off. The results of the analysis show that after the IGBT defects reach a certain level, the solder layer voids, the solder layer fall off, and the solder layer cracks have a great influence on the IGBT junction temperature and stress. Among them, shedding and cracks have a greater influence on the stress of the solder layer.