RADIATION-SENSITIVE RESIN COMPOSITION AND METHOD OF FORMING RESIST PATTERN

1 . A radiation-sensitive resin composition comprising:

a first polymer, solubility of which in a developer solution is capable of being altered by an action of an acid, the first polymer comprising:

a first structural unit comprising a partial structure obtained by substituting a hydrogen atom of a carboxy group, a phenolic hydroxy group, or an amide group with a group represented by formula (1); and

a second structural unit comprising a phenolic hydroxy group; and

a compound comprising:

a monovalent radiation-sensitive onium cation comprising an aromatic ring obtained by substituting at least one hydrogen atom with a fluorine atom or a fluorine atom-containing group; and

a monovalent organic acid anion,

wherein, in the formula (1),

R 1 represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms;

R 2 , R 3 , one or a plurality of R 4 s, one or a plurality of R 5 s, R 6 , and R 7 each independently represent a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and optionally two groups among R 2 , R 3 , one or a plurality of R 4 s, one or a plurality of R 5 s, R 6 , and R 7 taken together represent an aliphatic ring having 4 to 20 ring atoms together with the carbon atom or the carbon chain to which the two groups bond, wherein in a case in which R 6 or R 7 represents the substituted monovalent hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon group comprises at least one hydrogen atom;

n is an integer of 0 to 5; and

* denotes a site of bonding to an ethereal oxygen atom of the carboxy group, an oxygen atom of the phenolic hydroxy group, or a nitrogen atom of the amide group.

2 . The radiation-sensitive resin composition according to claim 1 , wherein the radiation-sensitive onium cation is represented by formula (2-1) or formula (2-2):

wherein, in the formula (2-1),

a is an integer of 0 to 7, b is an integer of 0 to 4, and c is an integer of 0 to 4, wherein a sum of a, b, and c is no less than 1;

R 8 , R 9 , and R 10 each independently represent a halogen atom, a hydroxy group, a nitro group, or a monovalent organic group having 1 to 20 carbon atoms, wherein

at least one of R 8 , R 9 , and R 10 represents a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms,

in a case in which a is no less than 2, a plurality of R 8 s are identical or different from each other,

in a case in which b is no less than 2, a plurality of R 9 s are identical or different from each other, and

in a case in which c is no less than 2, a plurality of R 10 s are identical or different from each other;

R 11 and R 12 each independently represent a hydrogen atom, a fluorine atom, or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms, or R 11 and R 12 taken together represent a single bond; and

n 1 is 0 or 1, and

in the formula (2-2),

d is an integer of 1 to 7 and e is an integer of 0 to 10,

wherein

in a case in which d is 1, R 13 represents a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms,

in a case in which d is no less than 2, a plurality of R 13 s are identical or different from each other, and each R 13 represents a halogen atom, a hydroxy group, a nitro group, or a monovalent organic group having 1 to 20 carbon atoms, wherein at least one of the plurality of R 13 s represents a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms;

R 14 represents a single bond or a divalent organic group having 1 to 20 carbon atoms;

R 15 represents a halogen atom, a hydroxy group, a nitro group, or a monovalent organic group having 1 to 20 atoms, wherein in a case in which e is no less than 2, a plurality of R 15 s are identical or different from each other;

n 2 is 0 or 1; and

n 3 is an integer of 0 to 3.

3 . The radiation-sensitive resin composition according to claim 1 , wherein the first structural unit is represented by formulae (3-1) to (3-3):

wherein, in the formulae (3-1) to (3-3), Z represents the group represented by the formula (1),

in the formula (3-1), R 16 represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group,

in the formula (3-2), R 17 represents a hydrogen atom or a methyl group; R 18 represents a single bond, an oxygen atom, —COO—, or —CONH—; Ar 1 represents a group obtained by removing two hydrogen atoms from a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 ring atoms; and R 19 represents a single bond or —CO—, and

in the formula (3-3), R 20 represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; and R 21 represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.

4 . The radiation-sensitive resin composition according to claim 1 , further comprising a second polymer having a percentage content of fluorine atoms being higher than a percentage content of fluorine atoms of the first polymer.

5 . The radiation-sensitive resin composition according to claim 1 , wherein R 1 in the formula 1 represents a hydrogen atom.

6 . The radiation-sensitive resin composition according to claim 1 , wherein n in the formula (1) is 0 or 1.

7 . A method of forming a resist pattern, the method comprising:

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

exposing the resist film; and

developing the resist film exposed.