Polymethacrylate copolymers used as single-layer resists (SLR) were investigated in this study. A photoacid generator (PAG) in the chemically amplified resist (CAR) can generate a Bronsted proton after light stimulation, which can catalyze the deprotection reaction of t-butyl methacrylate during the postexposure baking (PEB) process. Excimer lasers (KrF and ArF) were used as light source to evaluate the lithographic performance of resists. The hydrophobic property of the resist changed to hydrophilic property after the deprotection reaction by light exposure, which made the exposed resist soluble in the base developer. The deprotection reaction was analyzed by using FTIR and the reaction kinetics of the resist is discussed. The effects of the t-butyl methacrylate and the isobornyl methacrylate in the resists on the light sensitivity, contrast, reactive ion etching (RIE) resistance, and lithographic performance were systematically investigated.