Phase-field simulation of microstructure changes and crack propagation at Cu-Al wire bonding interface under high temperature circumstance

Reliability test criteria for automotive and industrial applications, have tended to require longer-term test periods at higher surrounding temperatures than those conditions for other applications. This background led us to develop a new simulation method to predict HTSL (High Temperature Storage Life) test reliabilities at conductive bonding interfaces. In this paper, we focused on microstructure changes and crack propagation at an interface formed after Cu wire bonding to Al pad, inside a wire bonding package. Through the cross-section analyses after HTSL tests, we had considered crack propagation mechanism, and successfully developed a new simulation method employing phase-field model to predict lifetime of the Cu-Al bonding interface.