Radiation-sensitive resin composition, method for forming pattern, and method for producing monomeric compound

A radiation-sensitive resin composition comprising:

• a resin comprising a structural unit A represented by formula (1);
• at least one radiation-sensitive acid generator selected from the group consisting of a radiation-sensitive acid generator represented by formula (2-1) and a radiation-sensitive acid generator represented by formula (2-2);
• and
• a solvent:
• wherein
• R1 and R2 are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group,
• R3 is an acid-dissociable group or a non-acid-dissociable group, provided that when one R3 is present, the R3 is an acid-dissociable group and when two or more R3s are present, at least one of the two or more R3s is an acid-dissociable group, and when two or more R3s are present, the two or more R3s are the same or different from each other,
• R41 is a hydrogen atom or a protective group to be deprotected by action of an acid, and when two or more R41s are present, the two or more R41s are the same or different from each other,
• R51 is a cyano group, a nitro group, an alkyl group, a fluorinated alkyl group, an alkoxycarbonyloxy group, an acyl group, or an acyloxy group, and when two or more R31s are present, the two or more R51s are the same or different from each other, and
• n1 is an integer of 0 to 2, m1 is an integer of 1 to 8, m2 is an integer of 1 to 8, and m3 is an integer of 0 to 6, provided that n1, m1, m2, and m3 satisfy 2≤m1+m2+m3≤2n1+5;
• R5b—SO3−X2+ (2-2)
• wherein
• in the formula (2-1),
• n2 is an integer of 1 to 5,
• Rf1 and Rf2 are each independently a hydrogen atom, a fluorine atom, or a fluoroalkyl group, provided that when n2 is 1, at least one of Rf1 and Rf2 is a fluorine atom or a fluoroalkyl group and when n2 is 2 to 5, at least one of two or more Rf1s and two or more Rf2s is a fluorine atom or a fluoroalkyl group, the two or more Rf1s are the same or different from each other, and the two or more Rf2s are the same or different from each other,
• L1 is a divalent linking group,
• R5a is a monovalent organic group having a cyclic structure,
• x1+ is a monovalent onium cation;
• in the formula (2-2),
• R5b is a monovalent organic group, and
• X2+ is a monovalent onium cation whose atom having a positive charge is not an atom forming a cyclic structure.