Sub-55 nm Etch Process Using Stacked-Mask Process

Abstract

Using a stacked mask process (S-MAP) with spun-on carbon (SOC) film, 56 nm line and space patterns of SiO2 were successfully etched. It was found that deformation of the SOC line pattern which occurred at line dimensions under 60 nm during SiO2 reactive ion etching (RIE) using fluorocarbon gas, originates from fluorination of the SOC film. By decreasing the hydrogen content of the SOC film, this cause of line pattern deformation was suppressed effectively.