Abstract: Disclosed is a novel monomer having a lactone skeleton, which is useful typically as a monomer component typically for a highly functional polymer, because, when the monomer is applied typically to a resist resin, the resin is satisfactory stable and resistant typically to chemicals, is highly soluble in organic solvents, and has improved hydrolyzability and/or water solubility after hydrolysis. The monomer having a lactone skeleton is represented by following Formula (1), wherein Ra represents a hydrogen atom, halogen atom, or substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; R1 represents a group having a lactone skeleton; and Y represents a bivalent organic group having 1 to 6 carbon atoms.

Abstract: A polymeric compound having a repeated unit corresponding to an unsaturated carboxylic acid hemiacetal ester represented by the following formula (1); wherein Ra is a hydrogen atom, a halogen atom, an alkyl group of carbon number 1 to 6 or a haloalkyl group of carbon number 1 to 6, Rb is a hydrocarbon group having a hydrogen atom at a first poison, Rc is a hydrogen atom or a hydrocarbon group and Rd is an organic group having a cyclic skeleton. This polymeric compound, further, may have a repeated unit corresponding to at least one monomer selected from a monomer having a lactone skeleton, a monomer having a cyclic ketone skeleton, a monomer having an acid anhydride group and a monomer having an imide group [except for a repeated unit corresponding to the said unsaturated carboxylic acid hemiacetal ester] and/or a repeated unit corresponding to at least one monomer selected from a monomer having a hydroxyl group and others.