Positive resist composition and pattern forming method using the same

1. A positive resist composition, comprising:

(A) a resin having a repeating unit represented by formula (A), which decomposes under an action of an acid to increase a solubility of the resin (A) in an alkali developer:

wherein R 2 represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom;

L represents a single bond or a divalent linking group;

A represents a monovalent organic group;

Rf represents an alkyl group, a cycloalkyl group or an aryl group; and

each of the alkyl group, cycloalkyl group and aryl group represented by Rf is unsubstituted or has an alkyl group, a cycloalkyl group, or a halogen atom as a substituent.

2. The positive resist composition according to claim 1 ,

wherein in formula (A), A is an alkyl, cycloalkyl or aryl group substituted by a group selected from the group consisting of a halogen atom, a cyano group and a nitro group.

3. The positive resist composition according to claim 1 ,

wherein in formula (A), Rf is an alkyl or aryl group substituted by a halogen atom.

4. The positive resist composition according to claim 1 ,

wherein R 2 represents a hydrogen atom or a methyl group.

5. The positive resist composition according to claim 1 ,

wherein L represents a single bond, an arylene group, an ester group or an amido group.

6. The positive resist composition according to claim 1 , which further comprises (B) a compound capable of generating an acid upon irradiation with actinic rays or radiation.

7. A pattern forming method, comprising:

forming a resist film from the positive resist composition according to claim 1 ; and

exposing and developing the resist film.

8. The positive resist composition according to claim 6 ,

wherein the compound capable of generating an acid upon irradiation with actinic rays or radiation (B) is a compound capable of generating a sulfonic acid upon irradiation with actinic rays or radiation and is a diazonium salt, a phosphonium salt, a sulfonium salt, an iodonium salt, an imidosulfonate, an oxime sulfonate, a diazodisulfone, a disulfone or an o-nitrobenzyl sulfonate.

9. The positive resist composition according to claim 6 ,

wherein the compound capable of generating an acid upon irradiation with actinic rays or radiation (B) is a compound capable of generating a sulfonic acid upon irradiation with actinic rays or radiation and is a sulfonium salt, an iodonium salt, an imidosulfonate, an oxime sulfonate, a diazodisulfone or a disulfone.

10. The positive resist composition according to claim 6 ,

wherein the compound capable of generating an acid upon irradiation with actinic rays or radiation (B) is a compound capable of generating a sulfonic acid upon irradiation with actinic rays or radiation and is represented by formula (ZI), (ZII) or (ZIII):

wherein R 201 , R 202 and R 203 each independently represents an organic group; two members out of R 201 to R 203 may combine to form a ring structure; X − represents an organic sulfonate anion; and R 204 to R 207 each independently represents an aryl group, an alkyl group or a cycloalkyl group.

11. A positive resist composition, comprising:

(A) a resin having a repeating unit represented by formula (A), which decomposes under an action of an acid to increase a solubility of the resin (A) in an alkali developer:

wherein R 2 represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom;

L represents a single bond or a divalent linking group;

A represents a monovalent organic group; and

Rf represents an alkyl or aryl group substituted by a halogen atom,

wherein the resin (A) further contains at least one of a repeating unit represented by formula (1) and a repeating unit represented by formula (2):

wherein in formula (1), R 1 represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom; and

X represents a group which leaves under an action of an acid, and

in formula (2), R 2 represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom;

R 3 represents an alkyl group, a halogen atom, an aryl group, an alkoxy group, an alkoxycarbonyl group or an acyl group, and when a plurality of R 3 's are present, the plurality of R 3 's are the same or different;

n represents an integer of 0 to 4;

A l represents a hydrogen atom, a group which leaves under an action of an acid or a group having a group which decomposes under an action of an acid, and when a plurality of A 1 's are present, the plurality of A 1 's are the same or different; and

m represents an integer of 1 to 5, provided that m+n≦5.

12. The positive resist composition according to claim 11 ,

wherein in formula (A), A is an alkyl, cycloalkyl or aryl group substituted by a group selected from the group consisting of a halogen atom, a cyano group and a nitro group.

13. The positive resist composition according to claim 11 , which further comprises (B) a compound capable of generating an acid upon irradiation with actinic rays or radiation.

14. A pattern forming method, comprising:

forming a resist film from the positive resist composition according to claim 11 ; and

exposing and developing the resist film.

15. A positive resist composition, comprising:

(A) a resin having a repeating unit represented by formula (A), which decomposes under an action of an acid to increase a solubility of the resin (A) in an alkali developer; and

(B) a compound capable of generating a sulfonic acid upon irradiation with actinic rays or radiation which is a diazonium salt, a phosphonium salt, a sulfonium salt, an iodonium salt, an imidosulfonate, an oxime sulfonate, a diazodisulfone, a disulfone or an o-nitrobenzyl sulfonate;

wherein R 2 represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom;

L represents a single bond or a divalent linking group;

A represents a monovalent organic group;

Rf represents an alkyl group, a cycloalkyl group or an aryl group; and

each of the alkyl group, cycloalkyl group and aryl group represented by Rf may have an alkyl group, a cycloalkyl group, a halogen atom, an alkoxy group, a hydroxyl group, an amido group, an ester group, a cyano group, a nitro group or a sulfide group as a substituent.