Study of Ti/TiN bump defect formation mechanism and elimination by etch process optimization

Subtle Ti/TiN bump defects are observed after thermal annealing in the development step of a back-end-of-line (BEOL) via metallization. It disturbs the endpoint detection of a sequential tungsten (W) chemical-mechanical planarization (CMP) process and results in W residue on the surface of the wafer. SIMS analysis conducted before Ti/TiN ...More