Stress-based Model for Lifetime Estimation of Bond-Wire Contacts using Power Cycling Tests and Finite Element Modelling

In this paper, a lifetime model for bond wire contacts of Insulated Gate Bipolar Transistors (IGBT) power modules is reported. This model is based on power cycling tests obtained under accelerated conditions and a finite element model taking into account the electrical, thermal and mechanical coupling. It allows to estimate the bond-wires lifetime for a large scale of junction temperature swing amplitudes ("{) and stress durations (-). To build it, a numerical design of experiment was performed in both high and low stress values ("{). Then, a strain-life curve has been constructed where average strain values on a defined volume around the contact areas between top-metallization and the most exposed bond-wires to fatigue and lift-off have been used. As result, it has been shown that the total strain is linearly dependent with "{ and power law dependent with -. The combination of the strain-life relation and the strain dependency with stress parameters leads to the lifetime relationship. The obtained lifetime model has been satisfactorily validated with some additional experimental points obtained from literature and with a large range of values for -. This methodology can easily be replicated to other structures and is quite generic.