Radiation sensitive resin composition

A positive-tone radiation sensitive resin composition comprising:

• (A) a photoacid generator represented by the formula (1-1):
• wherein R1 and R2 may be either the same or different and each individually represent a hydrogen atom, an alkyl group containing 1-4 carbon atoms, R3 represents a hydroxyl group or —OR4, A1-indicates a monovalent anion originating from sulfonic acid, a denotes an integer of 4-7, and b is an integer of 0-7;
• wherein said —OR4 is an alkoxv group selected from the group consisting of methoxv group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group. i-butoxy group, sec-butoxy group, t-butoxy group, methoxymethoxv group, ethoxymethoxy group, n-propoxymethoxy group, i-propoxymethoxy group, 1-methoxyethoxy group, 1-ethoxyethoxy group, 1 -n-propoxyethoxy group, 1-i-propoxyethoxv group, 2-methoxyethoxv group, 2-ethoxyethoxy group, 2-n-propoxvethoxy group, 2-i-propoxyethoxv group, 1-methoxypropoxv group, 2-methoxypropoxy group, 3-methoxypropoxy group, 1 -ethoxypropoxy group, 2-ethoxypropoxy group, 3-ethoxypropoxy group, methoxycarbonyloxy group, ethoxycarbonyloxv group, n-propoxvcarbonvloxy group, i-propoxycarbonyloxy group, n-butoxycarbonyloxy group, i-butoxvcarbonyloxy group, sec-butoxycarbonyloxy group, 2-tetrahydrofuranvloxy group, 2-tetrahvdropyranyloxy group, benzvloxv group, o-methylbenzyloxy group, m-methylbenzvloxv group, p-methylbenzvloxy group, p-t-butylbenzyloxy group, p-methoxvbenzyloxy group, methoxycarbonylmethyl group, ethoxvcarbonylmethyl group, n-propoxvcarbonylmethyl group, i-propoxycarbonvlmethyl group, n-butoxycarbonylmethyl group, i-butoxycarbonylmethyl group, sec-butoxycarbonylmethyl group and t-butoxycarbonylmethvl group:
• (B1) an acid-cleavable group-containing resin which is insoluble or scarcely soluble in alkali, but becomes soluble in alkali when the acid-cleavable group is cleaved, or
• (B2) an alkali-soluble resin and an alkali solubility control agent.