Application of plasma polymerized methylsilane resist for all-dry 193 nm deep ultraviolet processing

Abstract

Preliminary experiments employing plasma polymerized methylsilane (PPMS) as a single and bilayer resist system demonstrated that the resist process developed at 248 nm is extendible for application at 193 nm. PPMS exhibited excellent photosensitivity with efficient photo-oxidative bleaching when exposed to 193 nm radiation in air. PPMS as thick as 200 nm demonstrated complete bleaching throughout the film. A nitrogen atmosphere was found to quench the photo-oxidative bleaching. However, upon switching the gas ambient to air, the photo-oxidative bleaching rapidly proceeded to completion. Both positive- and negative-tone images were achieved with PPMS at 193 nm depending upon the development process. Using negative-tone development in a chlorine plasma, 0.2 μm lines/spaces were resolved in 100 nm films at an exposure dose of 20 mJ/cm2 and with a depth of focus of nearly 1.0 μm.