Patent ID: 8247166
Filing Date: 2012-08-21
Classification: G03F

Abstract:
1. 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 resin comprising recurring units having an alkali-soluble group protected with an acid labile group which is eliminatable with acid, an acid generator, and a solvent, and prebaking the resist composition to remove the unnecessary solvent and form a first resist film, exposing the first 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 resin whereby the acid labile groups on the resin in the exposed area undergo elimination reaction so that the resin in the exposed area becomes alkali soluble, and developing the exposed resist film with an alkaline developer to form a first positive resist pattern, rendering the first positive resist pattern insoluble in a solvent used in a second resist composition to be subsequently coated and also insoluble in an alkaline developer to be applied upon subsequent patterning of the second resist composition, the insolubilizing step including application of heat and/or high-energy radiation, coating a second chemically amplified resist composition on the first resist pattern, prebaking the second resist composition to remove the unnecessary solvent and form a second resist film, exposing the second resist film to high-energy radiation in a second pattern of exposed and unexposed areas, and developing the exposed second resist film with an alkaline developer to form a second resist pattern, wherein the resin in the first resist composition comprises recurring units of the general formula (1): wherein R 1 is each independently hydrogen, methyl or trifluoromethyl, m is 1 or 2, n is 0 or 1, and “a” indicative of a ratio of the recurring units incorporated in the resin is in the range: 0.01≦a<1.