COMPOSITION FOR FORMING PHOTOSENSITIVE RESIST UNDERLAYER FILM

摘要

Disclosed is a composition for forming a resist underlayer film that is free from dissolution of a photoacid generator contained therein into the solvent of a coating photoresist and can be alkali developed at the same time when the photoresist film is alkali developed. Specifically disclosed is a composition for forming a resist underlayer film used in a lithography process, which contains a polymer (A), a crosslinkable compound (D), a photoacid generator (E) and a solvent (F). The polymer (A) contains unit structures represented by formula (1), formula (2) and formula (3), and when the total mole number of all the unit structures constituting the polymer is taken as 1.0, the ratio of the mole number (a) of the unit structures represented by formula (1), the ratio of the mole number (b) of the unit structures represented by formula (2) and the ratio of the mole number (c) of the unit structures represented by formula (3) are within the following ranges: 0.20 = a = 0.90, 0.05 = b = 0.60 and 0.001 = c = 0.40. The polymer (A) has a weight average molecular weight of 3,000-100,000.