A resist composition comprising a base polymer and a sulfonium or iodonium salt capable of generating fluorobenzenesulfonic acid bonded to iodized benzoic acid offers a high sensitivity and minimal LWR independent of whether it is of positive or negative tone.

A resist composition comprising a base polymer and a sulfonium or iodonium salt capable of generating sulfonic acid bonded to iodized benzene ring offers a high sensitivity and minimal LWR independent of whether it is of positive or negative tone.

A resist composition comprising a base polymer and a sulfonium or iodonium salt capable of generating sulfonic acid bonded to iodized benzene ring offers a high sensitivity and minimal LWR independent of whether it is of positive or negative tone.

A resist composition comprising a base polymer and a quencher in the form of an iodonium salt capable of generating fluorobenzoic acid bonded to iodized benzene offers a high sensitivity and minimal LWR independent of whether it is of positive or negative tone.

A resist composition comprising a base polymer and a quencher in the form of an iodonium salt capable of generating fluorobenzoic acid bonded to iodized benzene offers a high sensitivity and minimal LWR independent of whether it is of positive or negative tone.

A novel copolymer suitable for an optical film which is excellent in optical characteristics and has high retardation even in a thin film state, and an optical film containing the same are provided. A copolymer excellent in optical characteristics and easy to form a composite with a different polymer, and an optical film composed of the same are also provided.

A novel copolymer suitable for an optical film which is excellent in optical characteristics and has high retardation even in a thin film state, and an optical film containing the same are provided. A copolymer excellent in optical characteristics and easy to form a composite with a different polymer, and an optical film composed of the same are also provided.

A novel copolymer suitable for an optical film which is excellent in optical characteristics and has high retardation even in a thin film state, and an optical film containing the same are provided. A copolymer excellent in optical characteristics and easy to form a composite with a different polymer, and an optical film composed of the same are also provided.

The invention aims to provide a polymer that can exhibit excellent calcium phosphate scale inhibition performance. The invention relates to a sulfuric acid (salt) ester group-containing copolymer containing a structural unit (a) derived from a sulfuric acid (salt) ester group-containing monomer (A) represented by the formula (1) and a structural unit (b) derived from an unsaturated carboxylic acid monomer (B).

##STR00001##

The invention aims to provide a polymer that can exhibit excellent calcium phosphate scale inhibition performance. The invention relates to a sulfuric acid (salt) ester group-containing copolymer containing a structural unit (a) derived from a sulfuric acid (salt) ester group-containing monomer (A) represented by the formula (1) and a structural unit (b) derived from an unsaturated carboxylic acid monomer (B).

##STR00001##