Resist underlayer film-forming composition

1. A resist underlayer film-forming composition comprising:

a polymer including a repeating unit shown by a formula (1), having a dispersity of from 1.4 to 5.0, polystyrene-reduced weight average molecular weight of from 3000 to 10,000; and

a solvent,

wherein

each of R 3 to R 8 individually represent a group shown by a formula (2), a hydrogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxycarbonyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 14 carbon atoms, or a substituted or unsubstituted glycidyl ether group having 2 to 6 carbon atoms, wherein at least one of R 3 to R 8 represents the group shown by the formula (2), and

X represents a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkanediyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkanediyloxy group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkanediyloxy group having 3 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 14 carbon atoms, or a divalent group formed by an arbitrary combination thereof,

wherein

R 1 represents a single bond, a substituted or unsubstituted alkanediyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, and

R 2 represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms.

2. The resist underlayer film-forming composition according to claim 1 , further comprising an acid generator.

3. The resist underlayer film-forming composition according to claim 1 , further comprising a crosslinking agent.