Loop Height Effects on Bond Wire Reliability under Power cycling for SiC Power Module

As the most vulnerable component of the SiC power module, the bonding wire needs to be evaluated for its thermo-mechanical properties based on the failure mechanism. This work uses principal stress analysis to analyze compressive and tensile stress distribution in different parts of the bonding wire. From the stress decomposition perspective, axial stress’s effect on dislocation slip and the bending shear effect of radial stress are analyzed. Then, a series of finite element analyses have been carried out to evaluate the thermomechanical reliability of bonding wires under different loop heights. The simulation results show the variation trend of stress with height. Finally, the lifetime information of bonding wire with different loop heights is obtained through the power cycling test, which verifies the correctness of the simulation. In addition, we found that the axial average stress in the bonding area has a good linear relationship with lifetime in simulation, with a correlation coefficient of -0.9571.