The role of water in delamination in electronic packages: degradation of interfacial adhesion

Polymeric electronic packages subjected to standard Joint Electron Device Engineering Council (JEDEC) reliability testing are known to exhibit weakening and failures at the polymeric adhesive interfaces. Coupling agents are typically used as additives in epoxy-based materials to improve package reliability. Coupling agent chemistry and environment conditions, including pH, temperature and applied stress, are known factors that affect the rate of adhesion degradation and jeopardize the long-term reliability of the package. In this study, the subcritical interfacial debonding process is described. The debonding rates of polymers with silane, titanate and zirconate coupling agents were characterized at different temperatures by shear fracture tests and tapered double cantilever beam tests under mechanical loading and simultaneous exposure to controlled acidic environments. An analytical procedure was developed to delineate the material parameters governing adhesion degradation. Elevated temperature and acidity were shown to have a strong effect on package reliability, but mechanical loading was found to have a minimal effect on the rate of adhesion degradation. The effects of the JEDEC testing conditions on interfacial bond degradation are discussed using the chemical kinetic model.