Resist composition

A resist composition comprising

• a resin (A1) which has
• a structural unit having a sultone ring and being represented by formula (Ix),
• a structural unit represented by formula (II),
• a structural unit having an acid-labile group, and
• a structural unit having a lactone ring and being represented by formula (a3-2),
• a resin (A2) which consists of a structural unit having a fluorine atom and a structural unit having a non-leaving hydrocarbon group, and has no structural unit having an acid-labile group and no structural unit having a lactone ring;
• an acid generator, and
• a weak acid inner salt represented by formula (D);
• wherein Rx represents a C1 to C6 alkyl group that may have a halogen atom, a hydrogen atom or a halogen atom,
• Axx represents an oxygen atom, an —N(Rc)— group or a sulfur atom,
• Ax represents a C1 to C18 divalent saturated hydrocarbon group where a methylene group may be replaced by an oxygen atom or a carbonyl group,
• R41 represents a C1 to C12 alkyl group that may have a halogen atom or a hydroxy group, a halogen atom, a hydroxy group, a cyano group, a C1 to C12 alkoxy group, a C6 to C12 aryl group, a C7 to C18 aralkyl group, a glycidyloxy group, a C2 to C12 alkoxycarbonyl or a C2 to C4 acyl group,
• X11 represents an oxygen atom, a sulfur atom or a methylene group,
• ma represents an integer 0 to 9, and
• Rc represents a hydrogen atom or a C1 to C6 alkyl group;
• wherein R1 represents a hydrogen atom, a halogen atom or a C1 to C6 alkyl group that may have a halogen atom,
• L1 represents a single bond or *-L2-CO—O-(L3-CO—O)g—,
• * represents a binding position to an oxygen atom,
• L2 and L3 independently represent a C1 to C12 divalent hydrocarbon group,
• g represents 0 or 1, and
• R3 represents a C2 to C8 linear alkyl group,
• wherein La5 represents *—O— or *—O—(CH2)k3—CO—O—, k3 represents an integer of 1 to 7,
• * represents a binding position to a carbonyl group,
• Ra19 represents a hydrogen atom or a methyl group,
• Ra22 in each occurrence represents a carboxy group, a cyano group or a C1 to C4 aliphatic hydrocarbon group,
• q1 represents an integer of 0 to 3, and
• wherein RD1 and RD2 in each occurrence independently represent a C1 to C12 hydrocarbon group, a C1 to C6 alkoxy group, a C2 to C7 acyl group, a C2 to C7 acyloxy group, a C2 to C7 alkoxycarbonyl group, a nitro group or a halogen atom, and
• m′ and n′ independently represent an integer of 0 to 4.