Investigation of Creep Failure in Ag-4Pd Bonding Wire Under Dynamic Mechanical Analysis Tests

Ag-alloy wire is of particular interest in high-power integrated circuits (ICs) due to its superior physical properties, but studies on creep failure in Ag-alloy wire are extremely sparse. This article investigated the creep behavior of the widely used Ag-4Pd bonding wire at tensile stress levels of 20-80 MPa at constant temperature and in the temperature range of 300 degree celsius-400 degree celsius at constant tensile stress. The steady-state creep flow behavior was analyzed through fitting the Arrhenius power-law creep equation, and the rate-dependent process of creep deformation was found to be dislocation climb-controlled. The activation energy of creep in Ag-4Pd bonding wire is 133.86 kJ/mol within this temperature range, suggesting that fast diffusion paths could be involved. Results of the cross-sectional analysis of the brittle fractured wire correlate with the kinetic analysis from a phenomenological point of view, indicating diffusion paths through grain boundaries.