Effects of interfacial properties on the ductility of polymer-supported metal films for flexible electronics

Polymer-supported metal films as interconnects for flexible, large area electronics may rupture when they are stretched, and the rupture strain is strongly dependent upon the film/substrate interfacial properties. This paper investigates the influence of interfacial properties on the ductility of polymer-supported metal films by modeling the microstructure of the metal film as well as the film/substrate interface using the method of finite elements and the cohesive zone model (CZM). The influence of various system parameters including substrate thickness, Young's modulus of substrate material, film/substrate interfacial stiffness, strength and interfacial fracture energy on the ductility of polymer-supported metal films is systematically studied. Obtained results demonstrate that the ductility of polymer-supported metal films increases as the interfacial strength increases, but the increasing trend is affected distinctly by the interfacial stiffness.