Radiation-sensitive resin composition and resist pattern-forming method

1. A radiation-sensitive resin composition comprising:

a compound represented by formula (1b);

a first polymer that comprises a fluorine atom, an acid-labile group, and an alkali-labile group;

a second polymer that comprises an acid-labile group and either is unfluorinated or has a content of fluorine atoms less than a content of fluorine atoms of the first polymer;

a radiation-sensitive acid generator; and

a solvent,

wherein in the formula (1b),

X represents a carbonyl group;

Y + represents a monovalent radiation-degradable onium cation; and

R c represents an alkenediyl group having 2 to 20 carbon atoms,

wherein at least one of the first polymer and the second polymer comprises a structural unit represented by formula (2):

wherein in the above formula (2),

R 4 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

Y′ represents a carbonyloxyalkanediyl group having 2 to 20 carbon atoms, a carbonyloxycycloalkanediyl group having 4 to 20 carbon atoms, or a carbonyloxycycloalkanediyloxy group having 4 to 20 carbon atoms;

R 5 represents a hydrogen atom or a monovalent linear or branched hydrocarbon group having 1 to 10 carbon atoms; and

R 6 and R 7 each independently represent a monovalent linear or branched hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R 6 and R 7 taken together represent an alicyclic structure having 3 to 20 ring atoms together with the carbon atom to which R 6 and R 7 bond.

2. The radiation-sensitive resin composition according to claim 1 , wherein the first polymer comprises a structural unit represented by formula (2a), a structural unit represented by formula (2b), or both of the same,

wherein in the formula (2a),

R d represents a hydrogen atom, a methyl group or a trifluoromethyl group;

G represents a single bond, an oxygen atom, a sulfur atom, —CO—O—, —SO 2 —O—NH—, —CO—NH— or —O—CO—NH—; and

R e represents a monovalent fluorinated linear or branched hydrocarbon group having 1 to 6 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms,

and wherein in the formula (2b),

R f represents a hydrogen atom, a methyl group or a trifluoromethyl group;

R 1 represents a hydrocarbon group having 1 to 20 carbon atoms and having a valency of (s+1), or the hydrocarbon group to which an oxygen atom, a sulfur atom, —NR′—, a carbonyl group, —CO—O— or —CO—NH— bonds at an end thereof on a side linking to R 2 , wherein R′ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms;

R 2 represents a single bond or a divalent organic group having 1 to 20 carbon atoms;

W 1 represents a single bond or a divalent fluorinated linear or branched hydrocarbon group having 1 to 20 carbon atoms;

A 1 represents an oxygen atom, —NR″—, —CO—O—* or —SO 2 —O—*, wherein R″ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and wherein * denotes a biding site to R 3 ;

R 3 represents a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms; and

s is an integer of 1 to 3, wherein in a case where s is 1, R 1 optionally represents a single bond, wherein in a case where s is 2 or 3, a plurality of R 2 s are identical to or different from each other, a plurality of W 1 s are identical to or different from each other, a plurality of A 1 s are identical to or different from each other, and a plurality of R 3 s are identical to or different from other, and

wherein in a case where W 1 represents a single bond, R 3 represents a group that comprises a fluorine atom.

3. The radiation-sensitive resin composition according to claim 2 , wherein R 3 in the formula (2b) represents the alkali-labile group.

4. The radiation-sensitive resin composition according to claim 3 , wherein a proportion of the structural unit represented by the formula (2b) in the first polymer with respect to total structural units constituting the first polymer is 10 mol % to 90 mol %.

5. The radiation-sensitive resin composition according to claim 3 , wherein a proportion of the structural unit represented by the formula (2b) in the first polymer with respect to total structural units constituting the first polymer is 40 mol % to 80 mol %.

6. A resist pattern-forming method comprising:

applying the radiation-sensitive resin composition according to claim 1 on a substrate to provide a resist film;

exposing the resist film through a liquid immersion medium; and

developing the resist film exposed through the liquid immersion medium.

7. The radiation-sensitive resin composition according to claim 1 , wherein a content of the compound with respect to a total solid content of the radiation-sensitive resin composition is from 0.1% by mass to 30% by mass.

8. The radiation-sensitive resin composition according to claim 1 , wherein a content of the compound with respect to a total solid content of the radiation-sensitive resin composition is from 3% by mass to 10% by mass.

9. The radiation-sensitive resin composition according to claim 1 , wherein a content of the first polymer with respect to 100 parts by mass of the compound is from 5 parts by mass to 2000 parts by mass.

10. The radiation-sensitive resin composition according to claim 1 , wherein a content of the first polymer with respect to 100 parts by mass of the compound is from 25 parts by mass to 70 parts by mass.

11. The radiation-sensitive resin composition according to claim 1 , wherein in the formula (1b), R c represents an alkenediyl group having 3 or 4 carbon atoms.

12. The radiation-sensitive resin composition according to claim 1 , wherein in the formula (1b), R c represents 1,2-propenediyl group.