Addition polymerization of norbornene-based monomers has been pursued toward the fabrication of photoresists for next-generation microlithography, using condensed carbon dioxide as the developing solvent. Addition polymers containing a norbornyl backbone, for dry plasma etch resistance and high thermal stability, were synthesized to include fluorinated moieties and chemical amplification switching groups. These materials have been characterized and their lithographic properties evaluated. Solubility differences between exposed and non-exposed resist have been observed in these novel systems, which should provide the necessary contrast for high-resolution imaging. Lithographic imaging produced dense lines as small as 3 mu m. (c) 2006 Elsevier Ltd. All rights reserved.