Radiation-sensitive resin composition

A radiation-sensitive resin composition comprising:

• (a) the following copolymer (a-1) or copolymer (a-2), or a mixture of the copolymer (a-1) and copolymer (a-2):
• copolymer (a-1):
• a copolymer (I) which comprises a recurring unit shown by the following formula (1) and a recurring unit shown by the following formula (2),
• wherein R1 represents a hydrogen atom or a methyl group,
• wherein R2 represents a hydrogen atom or a methyl group, and R3 represents a t-butyl group or a group shown by the following formula (3),
• wherein R4 and R5 individually represent a hydrogen atom, a linear or branched alkyl group having 1-6 carbon atoms, or a 5-8 membered cyclic alkyl group;
• or R4 and R5 forma 5-8 membered carbon cyclic structure in combination together with the carbon atom of the formula (3), and R6 and R7 individually represent a hydrogen atom, a linear or branched alkyl group having 1-6 carbon atoms, or a 5-8 membered cyclic alkyl group, or R6 and R7 form a 5-8 membered carbon cyclic structure in combination with the carbon atom of the formula (3);
• copolymer (a-2):
• a copolymer (II) which comprises a recurring unit shown by the above formula (1) and a recurring unit shown by the following formula (4),
• wherein R8 represents a hydrogen atom or a methyl group, and R9 represents a tertiary alkyl group having 4-10 carbon atoms;
• (b) a photoacid generator;
• and
• (c) a compound shown by the following formula (5),
• wherein R10, R11, R12, and R13 individually represent a linear, branched, or cyclic alkyl group having 1-16 carbon atoms, a linear, branched, or cyclic alkenyl group having 2-16 carbon atoms, an aryl group having 6-15 carbon atoms, or an aralkyl group having 7-12 carbon atoms;
• or two of R10, R11, R12, and R13 form a 5-8 membered heterocyclic structure in combination with the nitrogen atom of the formula (5), and the other two individually represent a linear, branched, or cyclic alkyl group having 1-16 carbon atoms, a linear, branched, or cyclic alkenyl group having 2-16 carbon atoms, an aryl group having 6-15 carbon atoms or an aralkyl group having 7-12 carbon atoms;
• and R14 represents a monovalent hydrocarbon group having 5-16 carbon atoms, an acyl group or carboxyl group having 2-16 carbon atoms, or a group in which a monovalent hydrocarbon group having 1-16 carbon atoms is replaced by a carboxyl group.