A pattern is formed through positive/negative reversal by coating a chemically amplified positive resist composition comprising an acid labile group-bearing resin, a photoacid generator, and an organic solvent onto a substrate, prebaking the resist composition, exposing the resist film to high-energy radiation, post-exposure heating, and developing the exposed resist film with an alkaline developer to form a positive pattern; irradiating or heating the positive pattern to facilitate elimination of acid labile groups and crosslinking for improving alkali solubility and imparting solvent resistance; coating a reversal film-forming composition thereon to form a reversal film; and applying an alkaline wet etchant thereto for dissolving away the positive pattern.