We have developed a novel ArF resist polymer poly[carboxy- tricyclo(5.3.2.0)decanylmethyl methacrylate] [poly(TCDMACOOH)], which has a carboxyl substituent on the tricyclodecanyl group. This polymer exhibited good solubility (1.93 micrometer/sec) in a 2.38% TMAH solution, high transparency (70%/micrometer) at 193 nm, and a good dry-etching resistance for CF4 gas (1.2 times the etching rate of novolac resin). Furthermore, the resist composed of the partially protected copolymer poly(TCDMACOOH60-TCDMACOOtBu40) with a photoacid generator exhibits a resolution of 0.18 micrometer L/S using an ArF exposure system (NA equals 0.55).