New Positive EB Resist with Strong Resistance to Plasma Damage

Copolymers of methyl methacrylate (MMA) and 3-triethoxysilylpropyl methacrylate (ESPMA) were synthesized and employed as an electron beam (EB) resist. The copolymer with a content of 10 mol% ESPMA worked as a positive EB resist and had 4-10 times as strong a resistance as poly(methylmethacrylate) (PMMA) to CBrF 3 plasma etching. The resolution and sensitivity were almost the same as those of PMMA. From experimental results concerning the insolubility of the plasma-irradiated copolymer and measurement of IR spectra, the enhanced resistance to plasma etching appears to be caused by formation of a cross-linking structure based on the Si-O-Si linkage