Monomer, polymer, chemically amplified negative resist composition, and pattern forming method

Abstract

To provide a chemically amplified negative resist composition that exhibits an enhanced resolution during pattern formation and forms a resist pattern with improved LER, resolution, pattern fidelity, and dose margin, and a resist pattern forming method.SOLUTION: A chemically amplified negative resist composition comprises a monomer represented by the formula (A1), a polymer comprising repeat units derived from the monomer, and a base polymer comprising the polymer (in the formula, a is an integer from 0 to 4, RA represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, LA is -O- or -NH-, LB is a single bond, an ether bond, an ester bond, or an amide bond, W1 represents a hydrogen atom, an aliphatic hydrocarbon group with 1 to 10 carbon atoms, an aliphatic hydrocarbon carbonyl group with 2 to 10 carbon atoms, or an aryl group with 6 to 15 carbon atoms, and the aryl group may have a substituent).SELECTED DRAWING: None