Physics-Based Reliability Analysis of Power Modules at Substrate and Component Level

Abstract:
The research paper focuses on physics-based reliability investigation of power module structures at substrate and component level which will be designed for various automotive applications. The direct copper bond (DCB) substrate is attached onto a copper heatsink by sintered silver of different thicknesses. Thermal and electrical conductivity of the sintered silver layers (360 ± 69 W/m•K and 39 ± 6 MS/m respectively) are determined and the microstructure is characterized by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Thermal cycle tests are conducted on the samples by experiment and numerical simulation. The degradation of sintered layer increases with number of thermal cycles. On component level, analysis has been performed on different power modules including die top system (DTS) and copper bond pad metallization (Cu AIT) on SiC chip. Active power cycle tests (APCT) and thermal shock tests (TST) are performed to analyze different reliability issues. Cu AIT has higher lifetime than die top system.