Method for dry etching silicon carbide films for resist underlayer applications

Abstract

A substrate processing method is described for etching silicon carbide films for resist underlayer applications. The method includes providing a substrate containing a silicon carbide film thereon, and a photoresist layer defining a pattern over the silicon carbide film, plasma-exciting an etching gas containing a fluorocarbon-containing gas and an oxygen-containing gas, and exposing the substrate to the plasma-excited etching gas to transfer the pattern to the silicon carbide film, where at least a portion of a thickness of the photoresist layer survives the exposing. For example, the photoresist layer includes an EUV resist layer and the etching gas includes CFgas, Ogas, and Ar gas. In another example, the exposing includes exposing the substrate to a) a plasma-excited etching gas containing CFgas, Ogas, and Ar gas, and b) exposing the substrate to a plasma-excited Ar gas, where steps a) and b) are sequentially performed at least once.