Analyzing the Impact of Die Positions inside the Power Module on the Reliability of Solder Layers for Different Power Cycling Scenarios

Solder layers, used as bonding material inside the power module to attach the semiconductor die on Direct Bond Copper (DBC) substrate and DBC substrate on baseplate, are one of the regions most prone to failure. The failure usually occurs in the form of solder cracks and depends on various operating conditions, such as - maximum temperature, temperature swing, and heating time. The cracks generated inside the solder layers can eventually result in its delamination. Power modules are usually power cycled to estimate the failure sites and mechanisms. However, the failure mechanisms can vary depending on the frequency, amplitude, and range of the temperature in the Power Cycling Tests (PCT). In this study, we have used the Finite Element Method (FEM) in COMSOL Multiphysics to analyse the impact of the PCT on both die attach, and baseplate attach solder layers. Additionally, the effect of the degree of asymmetry in the die position on the reliability of both the solder layers are analysed. The FEA (Finite Element Analysis) results are analysed to have a better understanding about the aspects impacting the lifetime of the power module.