Positive resist composition

1. A positive resist composition comprising (A) a resin containing at least one group that is decomposed by the action of an acid to generate an alkali-soluble group and (B) at least two compounds selected from (B1) a compound that generates an aliphatic or aromatic sulfonic acid substituted with at least one fluorine atom, (B2) a compound that generates an aliphatic or aromatic sulfonic acid that does not contain a fluorine atom, (B3) a compound that generates an aliphatic or aromatic carboxylic acid substituted with at least one fluorine atom and (B4) a compound that generates an aliphatic or aromatic carboxylic acid that does not contain a fluorine atom, as (B) a compound that generates an acid upon irradiation of an actinic ray or radiation, wherein the group that is decomposed by the action of an acid contained in the resin (A) includes a group represented by the following formula (Y):

wherein R 1y to R 6y each independently represents a hydrogen atom, a fluorine atom, an alkyl group or a cycloalkyl group, provided that at least one of R 1y to R 6y represents a fluorine atom, an alkyl group substituted with a fluorine atom or a cycloalkyl group substituted with a fluorine atom; and Y represents a hydrogen atom or an organic group.

2. The positive resist composition as claimed in claim 1 , wherein the component of (B) contains at least one compound of (B1) and at least one compound selected from (B2) to (B4).

3. The positive resist composition as claimed in claim 1 , wherein the group that is decomposed by the action of an acid to generate an alkali-soluble group is a group represented by any one of groups represented by the following formulae (Z1) to (Z5):

wherein R 1z to R 3z each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group; R 4z and R 5z each independently represents a hydrogen atom or an alkyl group; R 6z represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group; two of R 1z , R 2z , and R 3z or two of R 4z , R 5z and R 6z may be combined with each other to form a cyclic structure; and at least one of R 1z , R 2z and R 3z or at least one of R 4z , R 5z and R 6z least one of the groups represented by Y as a substituent.

4. The positive resist composition as claimed in claim 3 , wherein a carbon atom in the resin, to which the group represented by any one of formulae (Z1) to (Z5) is directly connected, is substituted with a fluorine atom, an alkyl group substituted with a fluorine atom or a cycloalkyl group substituted with a fluorine atom.

5. The positive resist composition as claimed in claim 3 , wherein at least one of R 1z , R 2z and R 3z in any one of formulae (Z1), (Z3) and (Z4) or at least one of R 4z , R 5z , and R 6z in any one of formulae (Z2) and (Z5) is a cycloalkyl group.

6. The positive resist composition as claimed in claim 3 , wherein two of R 1z , R 2z , and R 3z in any one of formulae (Z1), (Z3) and (Z4) or two of R 4z , R 5z and R 6z in any one of formulae (Z2) and (Z5) are connected with each other to form a cyclic structure.

7. The positive resist composition as claimed in claim 5 , wherein the cycloalkyl group represented by any one of R 1z to R 6z or the cyclic structure formed by connecting two of R 1z , R 2z and R 3z in any one of formulae (Z1), (Z3) and (Z4) or two of R 4z , R 5z and R 6z in any one of formulae (Z2) and (Z5) is a cyclohexane structure, a bicyclo[2.2.1]heptane structure or a bicyclo[2.2.2]octane structure.

8. The positive resist composition as claimed in claim 3 , wherein a repeating unit containing the group represented by any one of formulae (Z1) to (Z5) is a repeating unit represented by the following formula (Za), (Zb), (Zc), (Zd) or (Ze):

wherein Zx represents a group represented by any one of formulae (Z1) to (Z3); Zy represents a group represented by any one of formulae (Z4) to (Z5);

in formula (Za), R 0a represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or a cycloalkyl group; R 01 to R 06 each independently represents a hydrogen atom, a fluorine atom, an alkyl group or a cycloalkyl group, provided that at least one of R 01 to R 06 represents a fluorine atom, an alkyl group substituted with a fluorine atom or a cycloalkyl group substituted with a fluorine atom; R 1a represents a hydroxy group, a halogen atom, a cyano group, an alkoxy group, an acyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group; j represents an integer of from 0 to 4; k represents an integer of from 1 to 5, provided that the sum total of j and k is 1 to 5;

in formula (Zb), R 01 to R 06 have the same meanings as R 01 to R 06 in formula (Za) respectively;

in formula (Zc), R 01 to R 06 have the same meanings as R 01 to R 06 in formula (Za) respectively; 1 represents 0 or 1; R c s each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or a cycloalkyl group;

in formula (Zd), R 0d to R 2d each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, an alkyl group substituted with a fluorine atom or a cycloalkyl group substituted with a fluorine atom; L 1 represents a single bond or a divalent connecting group; and in formula (Ze), R 0e to R 2e each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or a cycloalkyl group; L 2 represents a single bond or a divalent connecting group; and 1 represents 0 or 1.

9. The positive resist composition as claimed in claim 3 , wherein a repeating unit containing the group represented by formulae (Z4) or (Z5) is a repeating unit represented by the following formula (Zd1) or (Zd2):

wherein R 0d to R 2d each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, an alkyl group substituted with a fluorine atom or a cycloalkyl group substituted with a fluorine atom; R 3d and R 4d each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group; Y represents a hydrogen atom or an organic group; L 3 represents a single bond or a divalent connecting group; X 1 and X 2 each independently represents a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, a cyano group, an alkyl group or a cycloalkyl group; or X 1 and X 2 may be combined with each other to form —CH 2 —, —C 2 H 4 — or —O—; X 3 and X 4 each independently represents a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, a cyano group, an alkyl group or a cycloalkyl group; or X 3 and X 4 may be combined with each other to form —CH 2 —, —C 2 H 4 — or —O—; and p and q each represents an integer of from 1 to 3.

10. The positive resist composition as claimed in claim 9 , wherein X 1 and X 2 in formula (Zd1) or X 3 and X 4 in formula (Zd2) are combined with each other to form —CH 2 —.

11. The positive resist composition as claimed in claim 1 , which further comprises (E) an organic basic compound.