Positive resist composition for immersion exposure and pattern-forming method using the same

1. A positive resist composition for immersion exposure comprising:

(A) a resin capable of increasing its solubility in an alkali developer by an action of an acid,

(B) a compound capable of generating an acid upon irradiation with actinic ray or radiation,

(C) a compound, other than compound (B), capable of generating an acid upon irradiation with actinic ray or radiation, and

(D) a surfactant,

wherein the acid generated by compound (B) satisfies conditions of V≧230 and V/S≦0.93 taking van der Waals volume of the acid as V (Å 3 ), and van der Waals surface area of the acid as S (Å 2 )

wherein the compound (B) is a sulfonium salt compound having an anion represented by formula (Y):

in formula (Y), n 3 represents an integer of from 3 to 6 and n 4 represents an integer of from 3 to 6.

2. The positive resist composition for immersion exposure as claimed in claim 1 ,

wherein the acid further satisfies the conditions of 0.80≦V/S≦0.90.

3. The positive resist composition for immersion exposure as claimed in claim 1 ,

wherein the resin (A) comprises a repeating unit having a group capable of decomposing by the action of an acid and represented by formula (I):

wherein R 1 , R 2 and R 3 each represents an alkyl group, a cycloalkyl group, or an alkenyl group, and at least two of R 1 to R 3 may be bonded to each other to form a ring.

4. The positive resist composition for immersion exposure as defined in claim 1 ,

wherein surfactant (D) is selected from the group consisting of a fluorine surfactant, a silicon surfactant, and a surfactant containing both a fluorine atom and a silicon atom.

5. The positive resist composition for immersion exposure as defined in claim 1 ,

wherein surfactant (D) is a fluorine-based nonionic surfactant.

6. The positive resist composition for immersion exposure as claimed in claim 1 , wherein compound (A) contains a repeating unit represented by formula (AI)

wherein R b0 represents a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms, wherein the halogen atom may be a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom;

A′ represents a single bond, an ether group, an ester group, a carbonyl group, an alkylene group, or a divalent linking group obtained by combining these groups; and

B 2 represents a group represented by any of formulae (III-1) to (III-5):

wherein R 1b , R 2b , R 3b , R 4b , and R 5b each represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl group, an alkoxycarbonyl group, an alkyl-sulfonylimino group, or an alkenyl group, and two of R 1b to R 5b may be bonded to each other to form a ring.

7. A positive resist composition for immersion exposure comprising:

(A) a resin capable of increasing its solubility in an alkali developer by an action of an acid, and

(B) a compound capable of generating an acid upon irradiation with actinic ray or radiation,

wherein the acid satisfies conditions of V≧230 and V/S≦0.93 taking van der Waals volume of the acid as V (Å 3 ), and van der Waals surface area of the acid as S (Å 2 )

wherein the compound (B) comprises a sulfonium salt compound having an anion represented by formula (Y):

in formula (Y), n 3 represents an integer of from 3 to 6 and n 4 represents an integer of from 3 to 6, and

a sulfonium salt compound having an anion represented by formula (X):

in formula (X), Rx represents an alkyl group, —OR′ 1 , —C(═O)R′ 1 , —C(═O)OR′ 1 , —SO 2 R′ 1 , or —SO 3 R′ 1 ; Ay represents a single bond, —SO 2 —, —SO 3 —, —SO 2 N(R′ 1 ) —, —CO 2 —, —C(═O)—, —C(═O)N(R′ 1 )—, or an alkylene group; R′ 1 represents a hydrogen atom or an alkyl group; Az represents a monocyclic or polycyclic hydrocarbon group, or an aryl group; n 1 represents an integer of from 1 to 4; and n 2 represents an integer of from 1 to 4.

8. The positive resist composition for immersion exposure as claimed in claim 7 , wherein compound (A) contains a repeating unit represented by formula (AI)

wherein R b0 represents a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms, wherein the halogen atom may be fluorine atom, a chlorine atom, a bromine atom, or an iodine atom;

A′ represents a single bond, and ether group, an ester group, an carbonyl group, an alkylene group, or a divalent linking group obtained by combining these groups; and

B 2 represents a group represented by any of formulae (III-1) to (III-5):

wherein R 1b , R 2b , R 3b , R 4b , and R 5b each represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl group, an alkoxycarbonyl group, an alkyl-sulfonylimino group, or an alkenyl group, and two of R 1b to R 5b may be bonded to each other to form a ring.

9. A pattern-forming method comprising:

forming a resist film with a positive resist composition for immersion exposure comprising:

(A) a resin capable of increasing its solubility in an alkali developer by an action of an acid, and

(B) a compound capable of generating an acid upon irradiation with actinic ray or radiation,

wherein the acid satisfies conditions of V≧230 and V/≦0.93 taking van der Waals volume of the acid as V (Å 3 ), and van der Waals surface area of the acid as S (Å 2 );

exposing the resist film through an immersion liquid so as to form an exposed resist film; and

developing the exposed resist film

and wherein the compound (B) is a sulfonium salt compound having an anion represented by formula (X):

in formula (X), Rx represents an alkyl group, —OR′ 1 , —C(═O)R′ 1 , —C(═O)OR′ 1 , —SO 2 R′ 1 , or —SO 3 R′ 1 ; Ay represents a single bond, —SO 2 —, —SO 3 —, —SO 2 N(R′ 1 )—, —CO 2 —, an oxygen atom, —C(═O)—, —C(═O)N(R′ 1 )—, or an alkylene group; R′ 1 represents a hydrogen atom or an alkyl group; Az represents an aliphatic monocyclic or polycyclic hydrocarbon group; n 1 represents an integer of from 1 to 4; and n 2 represents an integer of from 1 to 4.

10. The pattern-forming method of claim 9 ,

wherein the resin (A) comprises a repeating unit having a group capable of decomposing by the action of an acid and represented by formula (I):

wherein R 1 , R 2 and R 3 each represents an alkyl group, a cycloalkyl group, or an alkenyl group, and at least two of R 1 to R 3 may be bonded to each other to form a ring.

11. The pattern-forming method of claim 9 , wherein the sulfonium salt compound comprises a sulfonium salt compound having an anion represented by formula (X) and a sulfonium salt compound having an anion represented by formula (Y):

in formula (Y), n 3 represents an integer of from 3 to 6 and n 4 represents an integer of from 3 to 6.