Patent ID: 8129099

Claim:
A double pattern forming process comprising the steps of: coating a first chemically amplified positive resist composition onto a processable substrate, said resist composition comprising a resist polymer comprising recurring units having an alkali-soluble group protected with an acid labile group which is eliminatable with acid, a photoacid generator capable of generating an acid upon exposure to high-energy radiation, and an organic solvent, and prebaking the resist composition to remove the solvent to form a resist film, exposing the resist film to high-energy radiation in a first pattern of exposed and unexposed areas, post-exposure baking for causing the acid generated by the acid generator upon exposure to act on the acid labile groups on the resist polymer whereby the acid labile groups on the resist polymer in the exposed area undergo elimination reaction so that the resist polymer in the exposed area becomes alkali soluble, and developing the exposed resist film with an alkaline developer to form a first positive resist pattern, treating the first resist pattern so as to eliminate the acid labile groups on the resist polymer in the first resist pattern and to induce crosslinking in the resist polymer to such an extent that the resist polymer does not lose solubility in an alkaline developer, for thereby endowing the first resist 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, said reversal film-forming composition being a second chemically amplified positive resist composition comprising a resist polymer comprising recurring units having an alkali-soluble group protected with an acid labile group which is eliminatable with acid, a photoacid generator capable of generating an acid upon exposure to high-energy radiation, and an organic solvent, and prebaking the second resist composition to remove the solvent to form the reversal film, and exposing the reversal film to high-energy radiation in a second pattern of exposed and unexposed areas, post-exposure baking for causing the acid generated by the acid generator upon exposure to act on the acid labile groups on the resist polymer whereby the acid labile groups on the resist polymer in the exposed area undergo elimination reaction, and developing the exposed reversal film with an alkaline developer to form a second positive resist pattern, wherein the last step of developing the exposed reversal film with an alkaline developer to form a second resist pattern includes dissolving away the first resist pattern which has been converted to be soluble in the alkaline developer and achieving reversal transfer of the first resist pattern to the second resist pattern.