<p>In recent years, in response to the policy trend of a low-carbon society and energy conservation to improve global warming, the demand for pure electric personal mobile vehicles has continued to grow in the past decade. Automobile manufacturers are racing to invest in research and design of power modules, so that electric vehicles will gradually replace gasoline and diesel vehicles with carbon emissions. However, as the use conditions and power density of power modules increase with demand, traditional power modules with silicone gel can no longer meet the reliability requirements. In addition, the mismatch of thermal expansion coefficients of heterogeneous materials in the manufacturing process of the power module leads to serious warping behavior of the module. Therefore, this research designed a DBC (Direct Bonded Copper) structure power module, in which the thermal conductivity of AIN ceramic is 170 W/mk and the thickness is 0.635 mm, and epoxy resin is used as the filling material, and conducted experiments on the power module manufacturing process and thermal cycle test. It was found that the warpage of the DBC power module reached 340 μm after the manufacturing process, which caused the ceramic structure to withstand excessive bending stress, and then cracked under 250 thermal cycles test (TCT, -55℃~150℃), leading to module insulation failed. In order to improve the reliability of the DBC power module, the finite element method is used to analyze the mechanical behavior of the power module due to the thermal mismatch caused by the process and thermal cycle coupling effect, At the same time, the viscoplastic behavior of the solder material and the chemical shrinkage of the epoxy resin are considered, and verify it with experiments. Finally, the parameterized analysis of the properties of epoxy resin materials reduces the warpage of the power module, and further reduces the ceramic stress of the process, which has increased the reliability of thermal cycling.</p>

Coupling Effect of Manufacturing Process and Thermal Cycle Test on High-Power Module

Paper Proceedings: https://asmedigitalcollection.asme.org/InterPACK/InterPACK2021/volume/85505

ASME 2021 International Electronic Packaging Technical Conference and Exhibition (InterPACK2021)

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