Millen, White, Zelano & Branigan
Positive resist material
 A positive resists material for high energy-sensitive positive resists which can be developed in aqueous alkali solution, said material comprising (A) a polyhydroxystyrene resin wherein some hydroxyl groups are substituted by t-butoxycarbonyloxy groups, (B) a solution blocking agent, and (C) an onium salt, and being characterized in that said solution blocking agent contains at least one t-butoxycarbonyloxy group per molecule, said onium salt is bis(p-t-butylphenyl) iodinium trifluormethylsulfonate represented by the following formula (1): ##STR1## and the weight proportions of (A), (B), (C) are given by the relations: 0.07.ltoreq.B-.ltoreq.0.40, 0.005.ltoreq.C.ltoreq.0.15, 0.55.ltoreq.A, A+B+C=1. As the resist has low absorption at the exposure wavelength of a KrF exima laser, a fine pattern having vertical walls is easily formed. 
Nippon Telegraph and Telephone Corp. Shin-Etsu Chemical Co., Ltd.
G Y Y Y Y
G03F Y10S Y10S Y10S Y10S
inventional additional additional additional additional
Yoshio Osamu Akinobu Motoyuki Hiroshi
Kawai Watanabe Tanaka Yamada Ban