A negative pattern is formed by coating a resist composition onto a substrate, the resist composition comprising a polymer comprising recurring units having an acid labile group-substituted hydroxyl group, an acid generator, an onium salt of perfluoroalkyl ether carboxylic acid, and an organic solvent, prebaking, exposing, baking, and developing in an organic solvent such that the unexposed region of film is dissolved away and the exposed region of film is not dissolved. In image formation via positive/negative reversal by organic solvent development, the resist film is characterized by a high dissolution contrast between the unexposed and exposed regions.