Resin, resist composition and method for producing resist pattern, and compound

A compound represented by formula (IA):

• wherein, in formula (IA),
• R1 represents a hydrogen atom or a methyl group,
• X1 represents a single bond or —CO—O—* and * represents a bonding site to Ar1,
• X2 represents —CO—O—*, —O—*, —O—CO—*, —O—CO—(CH2)mm—O—* or —O—(CH2)nn—CO—O—* and * represents a bonding site to the benzene ring,
• mm and nn represent 0 or 1,
• Ar1 represents an aromatic hydrocarbon group having 6 carbon atoms which may have a substituent,
• R3 and R4 each independently represent a hydrogen atom or an acid-labile group, or R3 and R4 may combine together to form a group having an acetal ring structure,
• R5 represents a halogen atom, an alkyl fluoride group having 1 to 6 carbon atoms, an unsubstituted alkyl group having 1 to 12 carbon atoms, alkylcarbonyl group having 2 to 12 carbon atoms or an alkylcarbonyloxy group having 2 to 11 carbon atoms, and
• n′ represents an integer of 1 to 3, and when n′ is 2 or more, a plurality of R5 may be the same or different from each other.

A resin comprising:

• (i) a structural unit represented by formula (I),
• (ii) at least one structural unit selected from the group consisting of a structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2), and
• (iii) a structural unit represented by formula (a2-A),
• wherein the resin does not include an aromatic hydrocarbon group having more than 6 carbon atoms:
• wherein, in formula (I),
• R1 represents a hydrogen atom or a methyl group,
• X1 represents a single bond or —CO—O—* and * represents a bonding site to Ar1,
• X2 represents —CO—O—*, —O—*, —O—CO—*, —O—CO—(CH2)mm—O—* or —O—(CH2)nn—CO—O—* and * represents a bonding site to Ar2,
• mm and nn represent 0 or 1,
• Ar1 represents an aromatic hydrocarbon group having 6 carbon atoms which may have a substituent,
• Ar2 represents an aromatic hydrocarbon group having 6 carbon atoms which may have a substituent,
• R2 each independently represent an acid-labile group, or when two or more R2 exist, two R2 may combine together to form a group having an acetal ring structure,
• n represents an integer of 1 to 3, and when n is an integer of 2 or more, a plurality of R2 may be the same or different from each other:
• wherein, in formula (a1-1) and formula (a1-2),
• La1 and La2 each independently represent —O— or *—O—(CH2)k1—CO—O—, k1 represents an integer of 1 to 7, and * represents a bonding site to —CO—,
• Ra4 and Ra5 each independently represent a hydrogen atom or a methyl group,
• Ra6 and Ra7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group obtained by combining these groups,
• m1 represents an integer of 0 to 14,
• n1 represents an integer of 0 to 10, and
• n1′ represents an integer of 0 to 3, and
• wherein, in formula (a2-A),
• Ra50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
• Ra51 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group or a methacryloyloxy group,
• Aa50 represents a single bond or * —Xa51-(Aa52-Xa52)nb—, and * represents a bonding site to carbon atoms to which —Ra50 is bonded,
• Aa52 represents an alkanediyl group having 1 to 6 carbon atoms,
• Xa51 and Xa52 each independently represent —O—, —CO—O— or —O—CO—,
• nb represents 0 or 1, and
• mb represents an integer of 0 to 4, and when mb is an integer of 2 or more, a plurality of Ra51 may be the same or different from each other.