Patent ID: 9213235
Filing Date: 2015-12-15
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, an optional acid generator, and an organic solvent 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 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 3 is an acid labile group, 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)—, and a1 is a number in the range: 0<a1<1.0.