Salt, acid generator, resist composition and method for producing resist pattern

A salt represented by formula (I):

• wherein:
• Q1 and Q2 each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms,
• R11 and R12 each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms,
• z represents an integer of 0 to 6, and when z is 2 or more, a plurality of R11 and R12 may be the same or different from each other,
• X0 represents *—CO—O—, *—O—CO—, *—O—CO—O— or *—O—, and * represents a bonding site to C(R11)(R12) or C(Q1)(Q2),
• L1 represents a single bond or a hydrocarbon group having 1 to 28 carbon atoms which may have a substituent, and —CH2— included in the hydrocarbon group may be replaced by —O—, —S—, —SO2— or —CO—,
• Ar represents an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent,
• X1 is an oxygen atom,
• R1 represents a halogen atom or a haloalkyl group having 1 to 12 carbon atoms,
• R2 represents a halogen atom, a hydroxy group, a haloalkyl group having 1 to 12 carbon atoms or an alkyl group having 1 to 12 carbon atoms, and —CH2— included in the haloalkyl group and the alkyl group may be replaced by —O— or —CO—,
• m1 represents an integer of 1 to 6, and when m1 is 2 or more, a plurality of groups in parentheses may be the same or different from each other,
• m2 represents an integer of 0 to 4, and when m2 is 2 or more, a plurality of R2 may be the same or different from each other, and
• Z+ represents an organic cation.

A resist composition comprising an acid generator comprising a salt represented by formula (I), and a resin having an acid-labile group:

• wherein, in formula (I),
• Q1 and Q2 each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms,
• R11 and R12 each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms,
• z represents an integer of 0 to 6, and when z is 2 or more, a plurality of R11 and R12 may be the same or different from each other,
• X0 represents *—CO—O—, *—O—CO—, *—O—CO—O— or *—O—, and * represents a bonding site to C(R11)(R12) or C(Q1)(Q2),
• L1 represents a single bond or a hydrocarbon group having 1 to 28 carbon atoms which may have a substituent, and —CH2— included in the hydrocarbon group may be replaced by —O—, —S—, —SO2— or —CO—,
• Ar represents an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent,
• X1 represents an oxygen atom or a sulfur atom,
• R1 represents a halogen atom or a haloalkyl group having 1 to 12 carbon atoms,
• R2 represents a halogen atom, a hydroxy group, a haloalkyl group having 1 to 12 carbon atoms or an alkyl group having 1 to 12 carbon atoms, and —CH2— included in the haloalkyl group and the alkyl group may be replaced by —O— or —CO—,
• m1 represents an integer of 1 to 6, and when m1 is 2 or more, a plurality of groups in parentheses may be the same or different from each other,
• m2 represents an integer of 0 to 4, and when m2 is 2 or more, a plurality of R2 may be the same or different from each other, and
• Z+ represents an organic cation.