Numerical estimation of self-sputtering effect in ionized physical vapor deposition system

Abstract

During the fabrication of ultra large scale integrated (ULSI) circuits, Ti and TiN thin films are used as diffusion seed and barrier layers in Cu metal contacts. They are often deposited using magnetron sputtering technique where energetic ions bombard the target surface to release the target material. In ionized physical vapor deposition (IPVD) system, the sputtered atoms are ionized in the plasma and thus accelerated into narrow trenches for Ti and TiN thin film fabrication. In IPVD, the density of ionized sputter Ti atom and Ar discharge gas may be at the same range. Therefore, the self-sputtering effect from ionized sputter Ti atoms is important. In the present work, the sputtering yields of Ti and TiN target materials with 100-800 eV at normal incident Ar and Ti ions are calculated. In addition, the influence of N ions in TiN sputtering is also considered. The simulation results are calculated from TRIM, which is a vectorized Monte Carlo code simulation of ion-surface interaction using a binary collision mode. The depth phenomenon of sputtered target incident is also discussed.