Carboxylate, carboxylic acid generator, resin, resist composition and method for producing resist pattern

A carboxylate represented by formula (I) or a structural unit represented by formula (IP):

• wherein, in formula (I) and formula (IP),
• R4 represents a halogen atom, a hydroxy group or a haloalkyl group having 1 to 12 carbon atoms,
• R5 and R7 each independently represent a halogen atom, a hydroxy group, a haloalkyl group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 18 carbon atoms, each of the hydrocarbon group may have a substituent, and a —CH2—included in each of the haloalkyl group and the hydrocarbon group may be replaced by —O—, —CO—, —S—or —SO2—,
• R8 represents a branched alkyl group having 3 or 4 carbon atoms,
• A1 represents ***—X01-L-01-or ***-L01-X01—,
• X01 represents-O—or —S—,
• L01 represents a single bond or a hydrocarbon group having 1 to 18 carbon atoms, the hydrocarbon group may have a substituent, and —CH2—included in each of the hydrocarbon group may be replaced by —O—, —CO—, or —S—,
• *** represents a bonding site to a benzene ring to which I+ is bonded,
• A2 represents a hydrocarbon group having 1 to 20 carbon atoms, each of the hydrocarbon group may have a substituent of a halogen or a cyano group, and —CH2—included in each of the hydrocarbon group may be replaced by —O—, —CO—, or —S—,
• m1 represents an integer of 1 to 5, and when m1 is 2 or more, a plurality of groups in parentheses may be the same or different from each other,
• m2 represents 0,
• m4 represents an integer of 1 to 5, and when m4 is 2 or more, a plurality of R4 may be the same or different from each other,
• m5 represents 0,
• m7 represents an integer of 0 to 4, and when m7 is 2 or more, a plurality of R7 may be the same or different from each other,
• m8 represents 1,
• in which 1<m1+m7<5,0≤m2+m8≤5,
• X0 represents a single bond or a hydrocarbon group having 1 to 72 carbon atoms which may have a substituent, and —CH2—included in the hydrocarbon group may be replaced by —O—, —S—, —CO—or —SO2—,
• Rbb1 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
• X10 represents a single bond, *—O—**, *—CO—O—**, *—O—CO—O—** or *-Ax-Ph-Ay-**,
• Ph represents a phenylene group which may have a substituent,
• Ax represents a single bond, an ether bond, an ester bond or a carbonic acid ester bond,
• Ay represents a single bond, an ether bond, an ester bond or a carbonic acid ester bond,
• * represents a bonding site to carbon atoms to which Rbb1 is bonded,
• ** represents a bonding site to L10, and
• L10 represents a single bond or a hydrocarbon group having 1 to 36 carbon atoms which may have a substituent, and a —CH2—included in each of the hydrocarbon group may be replaced by —O—, —S—, —SO2—or —CO—.

A carboxylate represented by formula (I) or a structural unit represented by formula (IP):

• wherein, in formula (I) and formula (IP)
• R4, R5, and R7 and R8 each independently represent a halogen atom, a hydroxy group, a haloalkyl group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 18 carbon atoms, each of the hydrocarbon group may have a substituent, and a —CH2—included in each of the haloalkyl group and the hydrocarbon group may be replaced by —O—, —CO—, —S—or —SO2—,
• R8 represents an iodine atom, a fluorine atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, a haloalkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 3 carbon atoms,
• when m4 is 1 or more, one R4 of one or more R4s is an iodine atom,
• A1 and A2 each independently represent a hydrocarbon group having 1 to 20 carbon atoms, each of the hydrocarbon group may have a substituent, and —CH2—included in each of the hydrocarbon group may be replaced by —O—, —CO—, or —S—,
• m1 represents an integer of 1 to 5, 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 1 to 5, and when m2 is 2 or more, a plurality of groups in parentheses may be the same or different from each other,
• m4 represents an integer of 0 to 5, and when m4 is 2 or more, a plurality of R4 may be the same or different from each other,
• m5 represents an integer of 0 to 5, and when m5 is 2 or more, a plurality of R5 may be the same or different from each other,
• m7 represents an integer of 0 to 4, and when m7 is 2 or more, a plurality of R7 may be the same or different from each other,
• m8 represents an integer of 0 to 5, and when m8 is 2 or more, a plurality of R8 may be the same or different from each other,
• in which 1<m1+m7<5.0<m2+m8≤5, X0 represents a single bond or a hydrocarbon group having 1 to 72 carbon atoms which may have a substituent, and —CH2—included in the hydrocarbon group may be replaced by —O—, —S—, —CO—or —SO2—,
• Rbb1 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
• X10 represents a single bond, *—O—** *—CO—O—**, *—O—CO—O—** or *-Ax-Ph-Ay-**-,
• Ph represents a phenylene group which may have a substituent,
• Ax represents a single bond, an ether bond, an ester bond or a carbonic acid ester bond,
• Ay represents a single bond, an ether bond, an ester bond or a carbonic acid ester bond,
• * represents a bonding site to carbon atoms to which Rbb1 is bonded,
• ** represents a bonding site to L10, and
• L10 represents a single bond or a hydrocarbon group having 1 to 36 carbon atoms which may have a substituent, and a —CH2—included in each of the hydrocarbon group may be replaced by —O—, —S—, —SO2—or —CO—.