A novel positive chemically amplified resist containing partially t-butoxycarbonylmethlated poly(4-hydroxystyrene)s and 1,2-naphthoquinone-4-sulfonates (NQ4)s was investigated. The resists are effective for a wide region of UV lights including i-line and KrF excimer laser lights. The NQ4s photodecompose to form sulfonic acids which accelerate the decomposition of t-butyl moieties of the polymers to form carboxylic acid. Only a few % of NQ4s realize the chemically amplified resists. NQ4s having electron-withdrawing groups give resists with high sensitivities which provide excellent subhalf micron patterns when exposed to either i-line light or KrF excimer laser.