Effect of power module layer thickness on reliability

Abstract

With the rapid development and wide application of power modules, the requirements for their reliability are also increasing. Power modules are generally multi-layer structures, and it is critical to understand the impact of the thickness of each layer of a power module on its reliability. Taking IGBT power module as an example, this paper quantifies the reliability of power module through power cycle lifetime model and thermal cycle lifetime model, and uses finite element model to calculate the key parameters of reliability model. Then, the influence of each layer thickness on the reliability of power module is compared through global sensitivity analysis. In order to reduce the amount of calculation of sensitivity analysis, an active learning surrogate model is introduced to map the thickness of each layer into the reliability index of power module. Finally, the effects of common packaging materials such as solder, ceramic, and baseplate on the performance of the power module are compared. The sensitivity analysis results show that the thickness of chip solder layer, the thickness of copper layer on direct bonded copper (DBC) and the thickness of ceramic layer are the key factors affecting the power cycle lifetime of power modules, while the thickness of DBC ceramic layer and baseplate solder layer are the key factors affecting the thermal cycle lifetime of power modules.