A robust, deep-submicron copper interconnect structure using self-aligned metal capping method

A high reliable copper interconnects with metallic cap is studied. W-CVD process combined with pre-cleaning succeeded in self-aligned metal deposition on Cu interconnects surface. Degradation of leakage current between adjacent Cu wires is suppressed by process optimization. Reliability characteristics such as electromigration and stress-migration of metal capped Cu interconnect structure are investigated and are superior to those of conventional one. These results reveal that Cu and vacancy diffusion at the Cu wire surface is successfully suppressed by eliminating Cu/dielectric interface.