Dynamic delamination testing of patterned thin films: A combined experimental and numerical study

A novel combined experimental/numerical protocol is proposed to extract the fracture toughness of thin films used in microelectronics and other engineering applications. The testing method involves the dynamic delamination of a patterned thin film initiated by a laser-induced pressure pulse applied on the backside of the substrate. The kinetic energy imparted by the pulse to a weakly bonded (pre-cracked) region of the film is converted into fracture energy as the thin film delaminates in a controlled fashion. To support these experiments and extract the interface fracture toughness values, we develop a numerical scheme based on the combination of a spectral scheme used to model the elastodynamic response of the substrate and an explicit finite element scheme used to capture the dynamic response of the thin film. A cohesive failure model is adopted to couple the solutions in the two domains and to simulate the spontaneous propagation of the delamination front.