Positive resist composition

A positive resist composition which comprises (A) a compound which generates an acid upon irradiation with an actinic ray or radiation, and (B) a resin which is decomposed by the action of an acid to increase solubility in an alkaline developing solution and contains a repeating unit represented by the following formula (I) and a repeating unit represented by the following formula (V):

• wherein R1, R3, R13 and R15, which may be the same or different, each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or a haloalkyl group;
• R2 and R14, which may be the same or different, each independently represents a hydrogen atom, a cyano group, —CO—OR18 or —CO—N(R19)(R20);
• X1 and X4, which may be the same or different, each independently represents a single bond, an optionally substituted divalent alkylene, alkenylene or cycloalkylene group, —O—, —SO2—, —O—CO—R21—, —CO—O—R22— or —CO—N(R23)—R24—;
• R16 and R17, which may be the same or different, each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group, or R16 and R17 may be bonded to each other to form a ring;
• X represents an optionally substituted divalent alkylene, alkenylene or cycloalkylene group, or a divalent group formed by combining each of these alkylene, alkenylene and cycloalkylene groups with at least one of ether, ester, amido, urethane and ureido groups;
• Y represents a polycyclic alicyclic group having at least one alicyclic moiety selected from the group consisting of
• R18 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group or an acid-decomposable group;
• R19, R20 and R23, which may be the same or different, each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group or an alkenyl group, or R19 and R20 may be bonded to each other to form a ring;
• and R21, R22 and R24, which may be the same or different, each independently represents a single bond or a divalent alkylene, alkenylene or cycloalkylene group, which may contain at least one of ether, ester, amido, urethane and ureido groups;
• R16 represents a hydrogen atom, an alkyl group or a cycloalkyl group;
• R29 and R30, which may be the same or different, each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group;
• and two of R16, R29 and R30 may be bonded to each other to form a three-membered to eight-membered cyclic structure comprising carbon atoms and optionally one or more hetero atoms,
• wherein the composition is suitable for exposure using a far ultraviolet ray having a wavelength of 220 nm or less as an exposure light source,
• wherein the resin of component (B) further contains a repeating unit represented by the following formula (II):
• wherein R4 and R6, which may be the same or different, each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or a haloalkyl group;
• R5 represents a hydrogen atom, a cyano group, —CO—OR18 or —CO—N(R19)(R20);
• X2 represents a single bond, an optionally substituted divalent alkylene, alkenylene or cycloalkylene group, —O—, —SO2—, —O—CO—R21—, —CO—O—R22— or —CO—N(R23)—R24—;
• B represents a group which is decomposed by the action of an acid to increase solubility in an alkaline developing solution (an acid decomposable group);
• and R18, R19, R20, R21, R22, R23, and R24 are defined as above;
• and wherein the resin of component (B) still further contains a repeating unit represented by the following formula (IV):
• wherein R10 and R12, which may be the same or different, each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or a haloalkyl group;
• R11 represents a hydrogen atom, a cyano group, —CO—OR18 or —CO—N(R19)(R20);
• X3 represents a single bond, an optionally substituted divalent alkylene, alkenylene or cycloalkylene group, —O—, —SO2—, —O—CO—R21—, —CO—O—R22— or —CO—N(R23)—R24—;
• and R18, R19, R20, R21, R22, R23, and R24 are defined as above.