Advanced silver-based metallization patterning for ULSI applications

Silver metallization is being investigated for potential use in future integrated circuits. Unlike the proposed copper metallization, Ag thin films can be reactive ion etched at reasonable rates using a CF4 plasma. This etch technology is an atypical 'dry-etch' process since the formation of volatile products is not the main removal mechanism. The primary film removal mechanism, however, is the subsequent resist strip process. The effects of process conditions on the etch rate and post-etch surface roughness is also characterized. Our study shows that the silver etch process in the CF4 plasma depends strongly on the reactive neutrals and the removal rate is enhanced significantly by the presence of energetic ions as well. (C) 2001 Elsevier Science B.V. All rights reserved.