Adhesion and progressive delamination of polymer/metal interfaces

Bonding of metals using polymers has significantly increased in a wide range of modern applications including aerospace structures, microelectronic packages and bio-prosthetic components. The reliability of these structures are profoundly influenced by the interfacial fracture resistance (adhesion) and resistance to progressive debonding of the resulting polymer/metal interfaces. In this study we examine such interfacial fracture properties of representative metal/polymer interfaces commonly found in microelectronic and biomedical applications. Specifically, interface fracture mechanics techniques are described to characterize adhesion and progressive debonding behavior under cyclic fatigue loading. Cyclic fatigue debond-growth rates were measured from similar to 10(-10) to 10(-6) m/cycle and found to display a power-law dependence on the applied strain energy release rate range, Delta G. Fracture toughness test results show that the interfaces typically exhibit resistance-curve behavior, with a plateau interface fracture resistance, G(ss), strongly dependent on the interface morphology and the thickness of the polymer layer. Micromechanisms controlling interfacial adhesion and progressive debonding are discussed in terms of the prevailing deformation mechanisms and related to interface structure and morphology.