Effects of interface nonplanarity on the interface fracture energy of the TiN/SiO_2 system

摘要

Fracture mechanics models indicate that nonplanarity of the interface should have a significant effect on the measured fracture energy [1-5]. Previous work on a typical interconnect structure (Fig 1) has demonstrated that two thin film systems with nominally the same composition, but processed under different conditions exhibited different SiO_2/TiN interface fracture energies [6,7]. Upon investigation via cross-sectional TEM, it was found that the stronger interface was significantly rougher than the weaker interface. These results indicate that small changes in processing conditions can significantly effect both interface morphology and adhesion. Accordingly, in this study, samples differing in the flow rate of Ar to a plasma arc during deposition of a TiN layer were chosen in order to investigate the effects on the interface morphology and the resulting interface fracture energy.