Ester compounds having formula (1) wherein R.sup.1 is fluorine or C.sub.1-C.sub.10 fluoroalkyl, R.sup.2 is C.sub.1-C.sub.10 alkylene or fluoroalkylene, and R.sup.3 is an acid labile group are novel. They can be polymerized into polymers which are used to formulate resist compositions, which are processed by the lithography involving ArF exposure, offering many advantages including improved resolution and transparency, minimal line edge roughness, improved etch resistance, and especially minimal surface roughness after etching. ##STR00001##