Novel ester compounds, polymers, resist compositions and patterning process

摘要

A novel ester compound having an exo-form 2-alkylbicycloÄ2.2.1Üheptan-2-yl group as the protective group is provided as well as a polymer comprising units of the ester compound. The polymer is used as a base resin to formulate a resist composition having a higher sensitivity, resolution and etching resistance than conventional resist compositions.