Patent ID: 8105764

Claim:
A process for forming a pattern by way of positive/negative reversal, comprising the steps of: coating a chemically amplified positive resist composition onto a processable substrate, said resist composition comprising a resin comprising recurring units having acid labile groups which are eliminatable with acid, the resin turning to be soluble in an alkaline developer as a result of elimination of the acid labile groups, a photoacid generator capable of generating an acid upon exposure to high-energy radiation and optionally, a thermal acid generator capable of generating an acid upon heating, and an organic solvent, prebaking the resist composition to remove the solvent to form a resist film, exposing the resist film to high-energy radiation in a pattern of exposed and unexposed areas, post-exposure heating for causing the acid generated by the acid generator upon exposure to act on the acid labile groups on the resin whereby the acid labile groups on the resin in the exposed area undergo elimination reaction, and developing the exposed resist film with an alkaline developer to form a positive pattern, exposing to radiation or heating the positive pattern so that acid or heat acts to eliminate the acid labile groups on the resin in the positive pattern for thereby improving the alkali solubility of the resin, and to induce crosslinking in the resin to such an extent that the resin does not lose solubility in an alkaline wet etchant, for thereby endowing the positive pattern with resistance to an organic solvent to be used in a reversal film-forming composition, coating a reversal film-forming composition thereon to form a reversal film, and applying an alkaline wet etchant thereto for dissolving away the crosslinked positive pattern.