A novel high-pressure carbon dioxide (CO2) spin-coating apparatus was designed and constructed to produce high-quality thin films Of CO2-soluble photoresists based on 1H,1H-perfluorooctyl methacrylate/tert-butyl methacrylate copolymers. Film thicknesses were correlated to various process variables including rotational speed, solution viscosity, and evaporative driving force. The effects of these operating conditions on the film thickness and uniformity were compared to those of a theoretical model adapted for spin coating in CO2. Excellent correlation was found between the theoretical predictions and observed film properties, with the final films being of sufficient quality for use in photolithography. The potential of this spin-coating process in CO2 for developing a novel "dry lithography" is discussed.