Resist underlayer film-forming composition and method for forming resist pattern using the same

A resist underlayer film-forming composition, comprising an organic solvent and a polymer,

• wherein a main chain of the polymer comprises a structural unit represented by the following formula (3):
• wherein in formula (3),
• A1, A2, A3, A4, A5 and A6 each independently represent a hydrogen atom, a methyl group or an ethyl group;
• Y1 represents formula (4), formula (5), formula (6) or formula (7):
• wherein, in formulas (4) to (7),
• R4 and R5 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the phenyl group may be substituted with at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, a hydroxy group and an alkylthio group having 1 to 6 carbon atoms;
• R4 and R5 may be bonded to each other to form a ring having 3 to 6 carbon atoms;
• R6 represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the phenyl group may be substituted with at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, a hydroxy group and an alkylthio group having 1 to 6 carbon atoms;
• and
• Q represents formula (8) or formula (9):
• wherein, in formulae (8) and (9),
• Q1 represents an alkylene group having 1 to 10 carbon atoms, a phenylene group, a naphthylene group or an anthrylene group, and the phenylene group, the naphthylene group and the anthrylene group each may be substituted with at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, a hydroxy group and an alkylthio group having 1 to 6 carbon atoms;
• n4 and n5 each independently represent an integer of 0 or 1;
• and
• Y2 represents formula (4), formula (5) or formula (7), and
• wherein one or more terminal ends of the polymer are represented by the following formula (1) or (2):
• wherein, in formula (1) and formula (2),
• X represents a divalent organic group;
• A represents an aryl group having 6 to 40 carbon atoms;
• R1 represents a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms;
• R2 and R3 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms which may be substituted or an aryl group having 6 to 40 carbon atoms which may be substituted;
• n1 and n3 each independently represent an integer of 1 to 12;
• and
• n2 represents an integer of 0 to 11.