A negative pattern is formed by coating a resist composition comprising a polymer comprising recurring units having a carboxyl and/or hydroxyl group optionally substituted with an acid labile group and an acid generator capable of generating fluorinated tetraphenylborate onto a substrate, prebaking, exposing, baking, and developing in an organic solvent so that the unexposed region of resist film is dissolved away and the exposed region of resist film is not dissolved. The resist composition exhibits a high sensitivity and high dissolution contrast during organic solvent development and forms a fine hole or trench pattern via positive/negative reversal.