Complete-abrasive-free process for copper damascene interconnection

Abstract

Complete-abrasive-free process for copper (Cu) damascene interconnection has been developed. The process is a combination of a newly developed abrasive-free chemical polishing (AFP) of Cu and dry etching of a barrier metal layer. Complete stop-on-barrier characteristics of Cu polishing are attained by using the new polishing agent and a polyurethane polishing pad. This combination produces a very clean, scratch-free, anticorrosive polished surface, and the total depth of erosion and dishing is reduced to less than one fifth of that produced by conventional slurries even after 100% over polishing. And it is shown that the developed AFP significantly reduces both Cu line resistance and its deviation.