COMPOSITION FOR FORMING RESIST UNDERLAYER FILM, WHICH CONTAINS NOVOLAC RESIN HAVING POLYNUCLEAR PHENOL

摘要

[Problem] To provide a composition for forming a resist underlayer film, which can be used for the formation of a resist underlayer film that has high dry etching resistance and high wiggling resistance and that can exert good flatting performance and good filling performance in an uneven part or a depressed part. [Solution] A composition for forming a resist underlayer film, which contains a phenol-novolac resin produced by reacting a compound with an aromatic aldehyde or an aromatic ketone in the presence of an acidic catalyst, wherein the compound has at least three phenol groups and each of the phenol groups has such a structure that each of the phenol groups is bound to a tertiary carbon atom or such a structure that each of the phenol groups is bound to a quaternary carbon atom having a methyl group bound thereto. The phenol-novolac resin comprises a unit structure represented by formula (1), a unit structure represented by formula (2), a unit structure represented by formula (3), a unit structure represented by formula (4) or a combination of any two or more of the aforementioned unit structures.