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

1. 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

R 1 and R 2 are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group,

R 3 is an acid-dissociable group or a non-acid-dissociable group, provided that when one R 3 is present, the R 3 is an acid-dissociable group and when two or more R 3 s are present, at least one of the two or more R 3 s is an acid-dissociable group, and when two or more R 3 s are present, the two or more R 3 s are the same or different from each other,

R 41 is a hydrogen atom or a protective group to be deprotected by action of an acid, and when two or more R 41 s are present, the two or more R 41 s are the same or different from each other,

R 51 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 R 31 s are present, the two or more R 51 s are the same or different from each other, and

n 1 is an integer of 0 to 2, m 1 is an integer of 1 to 8, m 2 is an integer of 1 to 8, and m 3 is an integer of 0 to 6, provided that n 1 , m 1 , m 2 , and m 3 satisfy 2≤m 1 +m 2 +m 3 ≤2n 1 +5;

R 5b —SO 3 − X 2 +   (2-2)

wherein

in the formula (2-1),

n 2 is an integer of 1 to 5,

R f1 and R f2 are each independently a hydrogen atom, a fluorine atom, or a fluoroalkyl group, provided that when n 2 is 1, at least one of R f1 and R f2 is a fluorine atom or a fluoroalkyl group and when n 2 is 2 to 5, at least one of two or more R f1 s and two or more R f2 s is a fluorine atom or a fluoroalkyl group, the two or more R f1 s are the same or different from each other, and the two or more R f2 s are the same or different from each other,

L 1 is a divalent linking group,

R 5a is a monovalent organic group having a cyclic structure,

x 1 + is a monovalent onium cation;

in the formula (2-2),

R 5b is a monovalent organic group, and

X 2 + is a monovalent onium cation whose atom having a positive charge is not an atom forming a cyclic structure.

2. The radiation-sensitive resin composition according to claim 1 , wherein the resin further comprises a structural unit B derived from a (meth)acrylic ester-based monomer.

3. The radiation-sensitive resin composition according to claim 2 , wherein the structural unit B has an acid-dissociable group.

4. The radiation-sensitive resin composition according to claim 1 , wherein the resin further comprises a structural unit C represented by formula (5):

wherein

R α is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group,

L CA is a single bond, —COO—*, or —O—*, wherein * represents a hand bonding to an aromatic ring,

R 42 and R 52 have the same meaning as R 41 and R 51 in formula (1), respectively, and

n 3 is an integer of 0 to 2, m 3 is an integer of 1 to 8, and m 4 is an integer of 0 to 8, provided that n 3 , m 3 , and m 4 satisfy 1≤m 3 +m 4 ≤2n 3 +5.

5. The radiation-sensitive resin composition according to claim 1 , wherein in formula (1), a carbon atom bonded to COOR 3 and a carbon atom bonded to OR 41 are adjacent to each other.

6. The radiation-sensitive resin composition according to claim 1 , further comprising an onium salt compound that generates, by irradiation with a radioactive ray, an acid having a pKa higher than a pKa of an acid generated from the radiation-sensitive acid generator.

7. The radiation-sensitive resin composition according to claim 1 , wherein the onium cations in formula (2-1) and formula (2-2) are each independently a sulfonium cation or a iodonium cation.

8. A method for forming a pattern, comprising:

applying the radiation-sensitive resin composition according to claim 1 directly or indirectly onto a substrate to form a resist film;

exposing the resist film; and

developing the exposed resist film with a developer.

9. The method according to claim 8 , wherein in the exposing of the resist film, the resist film is exposed to an extreme ultraviolet ray or an electron beam.