Moisture-assisted failure mechanisms in underfill epoxy/silicon systems for microelectronic packaging

Synergistic effects of moisture and mechanical stress on debond kinetics of underfill epoxies used in semiconductor packaging are increasingly understood, however, the dramatic effect of increasing both temperature and humidity is not well known. We demonstrate a way to quantitatively measure the mechanical and kinetic behavior of an underfill epoxy resin containing a broad range of filler particles. With the introduction of fillers into the bisphenol-F-based resin, the fracture energy at the epoxy/Si interface is largely increased compared to the unfilled epoxy/Si interface. We characterize the cohesive and adhesive properties of each filled epoxy to the adjacent passivated silicon substrate and report on the moisture-assisted debonding kinetics in varying humidity and temperature environments, including accelerated testing conditions.