| abstract |
A positive resist composition comprises (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) an acid generator. The resin (A) is a polymer comprising specific recurring units, represented by formula (1). The acid generator (B) is a specific sulfonium salt compound. When processed by lithography, the composition is improved in resolution and forms a pattern with a satisfactory mask fidelity and a minimal LER. n n n n n n n n n n Herein R 1 is H or methyl, R 2 is an acid labile group, R 3 is CO 2 R 4 when X is CH 2 , R 3 is H or CO 2 R 4 when X is O, R 4 is a monovalent C 1 -C 20 hydrocarbon group, and m is 1 or 2. |