Resist composition and method for producing resist pattern, and salt and resin

A salt represented by formula (I):

• wherein
• Q1, Q2, R11, and R12 each independently represent a hydrogen atom, a fluorine atom, an alkyl group having 1 to 6 carbon atoms, or a perfluoroalkyl group having 1 to 6 carbon atoms;
• z represents an integer of 0 to 6, and when z is 2 or larger, a plurality of R11 and R12 may be the same or different from each other;
• X1 represents a single bond, —O—, —CO—, —S—, —SO—, —SO2—, —NR7—, or a combined group of these groups;
• mm1 represents 0 or 1;
• L1 represents a single bond, or a hydrocarbon group having 1 to 40 carbon atoms and optionally having a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• R7 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms;
• W1 represents a single bond, or a cyclic hydrocarbon group having 3 to 36 carbon atoms and optionally having a substituent, and —CH2— contained in the cyclic hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• A1 represents a single bond, or a hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon group optionally has a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• W2 represents a cyclic hydrocarbon group having 3 to 36 carbon atoms and an iodine atom, —CH2— contained in the cyclic hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—, and the cyclic hydrocarbon group optionally has a substituent other than the iodine atom;
• mm2 represents an integer of 1 to 5, and when mm2 is 2 or larger, a plurality of groups in parentheses may be the same or different from each other;
• R2 represents a hydrocarbon group having 1 to 36 carbon atoms and optionally having a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• m2 represents 1 or 2, and when m2 is 1, X is an iodine atom, and when m2 is 2, X is a sulfur atom and two R2 optionally together form a ring containing a sulfur atom, where —CH2— contained in the ring is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• R3 represents a halogen atom, or a hydrocarbon group having 1 to 18 carbon atoms, the hydrocarbon group optionally has a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• m3 represents an integer of 0 to 4, and when m3 is 2 or larger, a plurality of R3 may be the same or different from each other;
• L10 and L20 each independently represent a single bond, or a hydrocarbon group having 1 to 36 carbon atoms and optionally having a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• R20 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom;
• and
• X20 represents a single bond, —O—, —CO—, —NR7—, —S—, —SO—, —SO2—, a phenylene group optionally having a substituent, or a combined group of these groups.

A resin comprising a structural unit represented by formula (IP):

• wherein
• Q1, Q2, R11, and R12 each independently represent a hydrogen atom, a fluorine atom, an alkyl group having 1 to 6 carbon atoms, or a perfluoroalkyl group having 1 to 6 carbon atoms;
• z represents an integer of 0 to 6, and when z is 2 or larger, a plurality of R11 and R12 may be the same or different from each other;
• X1 represents a single bond, —O—, —CO—, —S—, —SO—, —SO2—, —NR7—, or a combined group of these groups;
• mm1 represents 0 or 1;
• L1 represents a single bond, or a hydrocarbon group having 1 to 40 carbon atoms and optionally having a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• R7 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms;
• W1 represents a single bond, or a cyclic hydrocarbon group having 3 to 36 carbon atoms and optionally having a substituent, and —CH2— contained in the cyclic hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• A1 represents a single bond, or a hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon group optionally has a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• W2 represents a cyclic hydrocarbon group having 3 to 36 carbon atoms and an iodine atom, —CH2— contained in the cyclic hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—, and the cyclic hydrocarbon group optionally has a substituent other than the iodine atom;
• mm2 represents an integer of 1 to 5, and when mm2 is 2 or larger, a plurality of groups in parentheses may be the same or different from each other;
• R2 represents a hydrocarbon group having 1 to 36 carbon atoms and optionally having a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• m2 represents 1 or 2, and when m2 is 1, X is an iodine atom, and when m2 is 2, X is a sulfur atom and two R2 optionally together form a ring containing a sulfur atom, where —CH2— contained in the ring is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• R3 represents a halogen atom, or a hydrocarbon group having 1 to 18 carbon atoms, the hydrocarbon group optionally has a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• m3 represents an integer of 0 to 4, and when m3 is 2 or larger, a plurality of R3 may be the same or different from each other;
• L10 and L20 each independently represent a single bond, or a hydrocarbon group having 1 to 36 carbon atoms and optionally having a substituent, and —CH2— contained in the hydrocarbon group is optionally replaced with —O—, —S—, —SO2—, —SO—, —NR7— or —CO—;
• R20 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom;
• and
• X20 represents a single bond, —O—, —CO—, —NR7—, —S—, —SO—, —SO2—, a phenylene group optionally having a substituent, or a combined group of these groups.