Pulse plasma assisted atomic layer deposition of W-C-N thin films for Cu interconnects

Abstract

W-C-N films have been deposited on a tetraethylorthosilicate (TEOS) interlayer dielectric with atomic layer deposition (ALD) cycles of WF6-N-2-CH4 gases and the exposure cycles of N-2 and CH are synchronized with a pulse plasma. The W-C-N films on TEOS layer follow the ALD mechanism, keep a constant deposition rate of 0.2 nm/cycle from 10 to 100 cycles, and have fairly low resistivity (300 mu Omega cm). As a diffusion barrier for Cu interconnection the W-C-N films maintain the amorphous phase and no Cu interdiffusion occurs even at 800 degrees C for 30 min.