A Time-Efficient Strain-Based Lifetime Prediction Method for Bond Wires Using Vibration Fatigue Tests and Finite Element Modeling

Failure of bond wires has become one of the main failure mechanisms of power modules. The rapid assessment of bond wires becomes increasingly important to satisfy the high-reliability requirements of new module products and shorten their development cycles to market. However, most of the preliminary lifetime evaluation methods for bond wires are mainly through time-consuming and expensive power cycling (PC) tests. Herein, a time-efficient lifetime prediction method for bond wires in insulated gate bipolar transistor (IGBT) modules is proposed to rapidly and economically evaluate the preliminary lifetime. The accurate transient thermomechanical finite element model (FEM) simulation is established, which is calibrated by infrared temperature measurement experiments and laser displacement experiments. In this way, the actual strain distribution on bond wires can be yielded, and more importantly, the plastic strain and elastic strain of bond wires that cannot be directly measured during normal PC tests can be accurately extracted. Then, four groups of vibration fatigue tests (VFTs) of different geometries of bond wires are meticulously completed for parameterization of the lifetime prediction model based on total strain. Finally, PC tests have been completed to further validate the effectiveness of the newly proposed lifetime prediction method.