<p>　　In response to technological progress and the development of a carbon-free society, hybrid/pure electric mobile vehicles and rail transportation systems have developed rapidly in recent years. High-power modules are key components for the conversion of power and electronic power systems, so high power modules are reliable assessment is essential. As automotive manufacturers have invested in the research and development of power modules, the reliability requirements for high power modules have become more stringent. The reliability tests of traditional high power modules in thermal cycling and power cycling have not met market requirements, and there is an urgent need for improvement and enhance. In addition, the structural layer stacking of high power modules generates thermal stress due to the mismatch of thermal expansion coefficients between different materials during the manufacturing process, which leads to module warpage and premature failure of the high power module in the thermal cycle test. Therefore, the influence of the manufacturing process on reliability must be considered. This research is aimed at proposing a DBC (Direct Bonded Copper) sandwich structure power module, using 170 W/mk high thermal conductivity of AIN ceramic material, the module size is 122mm*60mm*16mm, the selected filler is Epoxy resin. However, when the power module undergoes a thermal cycling condition of -55 to 150℃, the ceramic in the DBC structure is subjected to critical bending stress, which causes the ceramic to crack and fail. Therefore, the finite element analysis method of the coupling effect between the manufacturing process and the thermal cycle is established in the research, and the solder creep model and the chemical shrinkage characteristics of the epoxy resin are considered in the simulation analysis. Validate and establish finite element analysis methods and procedures through experiments, and observe the mechanical behavior analysis of the substrate warpage on the ceramic during the process and the cumulative increase in thermal cycle solder material creep. Finally, parameterized design is carried out for the material properties and module structure to improve the warpage of the process and reduce the residual bending stress of the ceramic due to the process, so as to further improve the thermal cycle reliability of the power module. In this study, the finite element method was used to verify the coupling effect of the power module process and thermal cycle and to verify it with experiments. At the same time, the carrier material and structure were optimized and discussed to provide a design reference for future power modules.</p>

Thermal Cycle Reliability Analysis of Direct Bonding Copper Power Module Considering the Manufacturing Process Effect

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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