Coating agent for reducing roughness of resist pattern, and method for forming resist pattern in which roughness is reduced

A coating agent for coating a resist pattern formed on a substrate to reduce the roughness of the resist pattern, comprising:

• a resin (A), a quaternary carbon-atom-containing compound (B), a solvent (S), and a basic compound (C),
• wherein the quaternary carbon-atom-containing compound (B) is a compound represented by the following formula (1):
• wherein R1 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, R2 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms or a group represented by —R7—O-(A-O)p—R8, R3 and R4 each independently represents an alkylene group having 1 to 4 carbon atoms, R5 represents a group represented by -(A-O)q—R8, R6 represents a group represented by -(A-O)r—R8, A represents an ethylene group or a propylene group, R7 represents an alkylene group having 1 to 4 carbon atoms, R8 represents a hydrogen atom or an alkyl group, p, q, and r each independently represents a positive number, and p+q+r represents 4 or more, and
• the basic compound (C) comprises a quaternary ammonium hydroxide represented by the following formula (C1):
• wherein Rc1, Rc2, Rc3, Rc4 are the same or different, and each independently represents a group selected from the group consisting of an alkyl group, a hydroxyalkyl group and an aralkyl group, and,
• at least one of the Rc1, Rc2, Rc3 and Rc4 is an aralkyl group, and the aralkyl group is a benzyl group.