CMP-free and CMP-less approaches for multilevel Cu/low-k BEOL integration

Abstract

A CMP-free process by electropolishing (EP) the planar contact plating (CP) Cu film and TaN dry etching which eliminate the stress induced peeling during CMP was demonstrated. Nanometer smoothness and a highly <111> texture of Cu can be achieved by optimizing the EP process. A 4-level Cu/low-k interconnect with CMP-less process was demonstrated with excellent yield. This process improves the throughput on ECP and CMP by two and has less dishing.