To investigate the effects of cyclic structures of polymers on the physical properties of photoresist, a series of copolymers consisting of various comonomers selected from 3,6-endo,oxo-1,2,3,6-tetrahydrophthalic anhydride (THPA), bornyl methacrylate (BMA), methacrylic acid (MA), t-butyl methacrylate (t-BMA), and 2-norborene (NB) was synthesized. The molecular weight, glass transition temperature, and the components of the synthesized copolymers were estimated. Photoresists consisting of the synthesized polymers and photoacid generator were prepared. The dependence of the molecular structures on the developers was investigated. The exposure characteristic curves of the photoresists were studied. The existence of the alicyclic comonomers was clearly found to increase the plasma resistance of the photoresist. The sensitivity, contrast, and exposed real image of the prepared photoresists were all investigated. The results obtained suggest that the alicyclic polymers synthesized in this investigation could be used as positive tone photoresists. (c) 2005 Wiley Periodicals, Inc.