Patent ID: 9182668
Filing Date: 2015-11-10
Classification: C08F,G03F

Abstract:
1. A pattern forming process comprising the steps of applying a resist composition comprising a polymer adapted to form a lactone ring under the action of an acid so that the polymer may reduce its solubility in an organic solvent, and an optional acid generator onto a substrate, prebaking the composition to form a resist film, exposing the resist film to high-energy radiation, baking, and developing the exposed film in an organic solvent-based developer to form a negative pattern wherein the unexposed region of resist film is dissolved away and the exposed region of resist film is not dissolved, said polymer comprising recurring units (a1) of the general formula (1): wherein R 1 is hydrogen or methyl, R 2 and R 3 are each independently hydrogen, fluorine or a straight, branched or cyclic monovalent hydrocarbon group of 1 to 8 carbon atoms, R 4 is hydrogen or a straight, branched or cyclic monovalent hydrocarbon group of 1 to 20 carbon atoms in which a constituent —CH 2 — may be substituted by —O— or —C(═O)—, R 5 and R 6 are each independently hydrogen or a straight, branched or cyclic monovalent hydrocarbon group of 1 to 8 carbon atoms, R 5 and R 6 may bond together to form a non-aromatic ring of 3 to 17 carbon atoms with the carbon atom to which they are attached, X 1 is a straight, branched or cyclic divalent hydrocarbon group of 1 to 20 carbon atoms in which a constituent —CH 2 — may be substituted by —O— or —C(═O)—, and k 1 is 0 or 1.