Quantitative Measurement of Interface Fracture Energy in Multi-Layer Thin Film Structures

Abstract

AbstractInterfacial debonding of multi-layer thin film systems can severely affect the reliability of devices. To quantitatively evaluate the interface adhesion strength, a sandwich structure four-point bending technique was developed. In the sandwich structure samples, the thin film structure of interest was diffusion bonded between two silicon substrates. A fourpoint bending method was applied to propagate a crack along the interface of interest. Two thin film systems with nominally the same structure, but processed under different conditions, were measured for their SiO2/TiN interface fracture energies. Results showed that the interface fracture energy of one system was about 50% larger than that of the other system. Cross-section TEM observations revealed that the stronger interface was also significantly rougher.