© 2020 Author(s). Atomic hydrogen dry etching was used for microstructure fabrication. Photolithography was proposed and achieved by a dry development process using atomic hydrogen irradiation. The reaction system of poly(methyl methacrylate) mixed with molecular benzophenone was examined as a model system for a proof-of-concept study. Optical patterning was experimentally made on a thin layer of poly(methyl methacrylate) with benzophenone by UV light exposure with a photomask. The reaction system acted as a negative tone resist in the proposed process. Thus, a model system for a new atomic hydrogen dry development process was proposed and successfully demonstrated.