Characterization of modification of 193-nm photoresist by HBr plasma

Abstract

HBr plasma treatments are used to decrease surface line edge roughness (LER) of patterned photoresist (PR). In this work the modification of two 193-nm photoresists by an HBr plasma treatment was characterized by Fourier Transform Infrared (FTIR) spectroscopy, 1H-NMR (Nuclear Magnetic Resonance) and gel permeation chromatography (GPC). PR modification was shown to follow similar schemes as the degradation of poly(methyl methacrylate) (PMMA) by UV light. Beside the cleavage of ester side-groups, this study showed extensive scission of PR chains, which will contribute to LER reduction by increasing PR chains mobility. However chain scission was accompanied by cross-linking, which may put a limit to the surface-smoothening potential of this technique. © 2011 The Electrochemical Society.