A new approach for evaluating thin film interface fracture toughness

A material configuration of central importance in microelectronics, optoelectronics, and thermal barrier coating technology is a thin film of one material deposited onto a substrate of a different material. Fabrication of such a structure inevitably gives rise to stress in the film due to lattice mismatch, differing coefficient of thermal expansion, chemical reactions, or other physical effects. Therefore, in general, the weakest link in this composite system often resides at the interface between the thin film and substrate. In order to make multi-layered electronic devices and structural composites with long-term reliability, the fracture behavior of the material interfaces must be known. This project is intended to address the problems associated with the deficiency of the existing methods, which show severe scatter in the existing data and the procedure dependence in thin film/coating evaluation methods, and offers an innovative testing procedure for the determination of interface fracture toughness applicable to thin coating materials in general.