Proceedings of the third Europeon workshop on Materials for advanced metallization
Hi-index | 2.88 |
Thermally stable, amorphous Ta-W-N diffusion barrier layer between Cu and Si substrate was deposited by reactive sputtering. In the Cu/Ta-W-N/Si system, a 50 nm thick Ta-W-N film was adequate to suppress penetration of Cu into the Si substrate upon annealing at 700 °C without significant structure change and solid-phase reaction. The Ta-W-N barrier fails by migration of Cu through the Ta-W-N layer to the Ta-W-N/Si interface and reaction with Si to form copper silicide. The crystallization temperature of Ta-W-N in the Cu/Ta-W-N/Si sample is as high as 800 °C. The failure of Ta-W-N 800 °C is directly related to the crystallization of Ta W-N.