Positive working resist composition

A positive working resist composition comprising (A1) a resin containing a repeating unit represented by formula (1) shown below and a repeating unit represented by formula (2) shown below and having a property of being insoluble or sparingly soluble in an alkali developing solution and becoming soluble in an alkali developing solution by the action of an acid, and (B) a compound capable of generating sulfonic acid upon irradiation with active rays or radiations in an amount of from 5 to 20% by weight based on the total solid content of the positive working resist composition:

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• wherein R1 represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoroalkyl group having from 1 to 4 carbon atoms;
• R2 represents a hydrogen atom, an alkyl group, a halogen atom, an aryl group, an alkoxy group or an acyl group;
• R3 and R4 each independently represent a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms;
• Z represents a hydrocarbon group having from 6 to 30 carbon atoms and containing at least one cyclic structural unit selected from an alicyclic structure, an aromatic cyclic structure and a bridged alicyclic structure;
• and n represents an integer of from 0 to 4.