Process for preparing fluorine-containing polymer and method of forming fine pattern using same

Abstract

There is provided a method of forming a fine pattern by using a practicable fluorine-containing polymer which has a high transparency to exposure light having a short wavelength such as Flaser and can undergo resolution of a fine pattern. The method comprises (I) a step for preparing a fluorine-containing polymer (A) having OH group which has a structural unit derived from a fluorine-containing norbornene derivative having OH group, (II) a step for preparing a fluorine-containing polymer (B) having a protective group by reacting a compound represented by X—CHOR, wherein X is Cl, Br or I; R is a hydrocarbon group having 1 to 30 carbon atoms in which a part or the whole of hydrogen atoms may be substituted with fluorine atoms, with the above-mentioned fluorine-containing polymer (A) having OH group in the presence of a base, (III) a step for preparing a resist composition comprising (a) the above-mentioned fluorine-containing polymer (B) having a protective group, (b) a photoacid generator and (c) a solvent, (IV) a step for forming a resist film comprising the above-mentioned resist composition on a substrate or on a given layer on the substrate, (V) a step for exposing by selectively irradiating a given area of the resist film with energy rays, and (VI) a step for subjecting the exposed resist film to developing to selectively remove the exposed portion of the resist film, thus forming a fine pattern.