Positive resist for KrF excimer laser lithography

In order to develop a new positive-tone, chemically amplified photoresist for 248 nm lithography, a copolymer containing acrylic silicon moiety was synthesized. The copolymer of 1,3-bis(trimethylsilyl)isopropyl methacrylate and 4-hydroxystyrene was prepared by free radical polymerization. The polymer structure, properties and acid catalyzed deprotection were evaluated by H-1 nuclear magnetic resonance, Fourier transform infrared, UV, thermogravimetric analysis and gel permeation chromatography. This polymer is thermally stable up to 150degreesC and is suitably transparent at the KrF laser output wavelength (248 nm). The lithographic evaluation shows the capability of 0.28 mum resolution using a KrF excimer laser stepper. (C) 2002 American Vacuum Society.