Composition for film formation, resist underlayer film and forming method thereof, pattern-forming method and compound

A compound represented by formula (1′):

• wherein in the formula (1′),
• R1, R2 and R3 each independently represent a group represented by formula (a′), wherein R1, R2 and R3 are identical or different;
• Ra′, Rb′, Rc′ and Rd′ each independently represent a halogen atom, a hydroxy group, an amino group, a sulfanyl group, or a monovalent organic group having 1 to 20 carbon atoms and not comprising an aromatic ring;
• x′, y′ and z′ are each independently an integer of 0 to 4;
• and
• w′ is an integer of 0 to 3,
• wherein in a case where Ra′ to Rd′ are each present in a plurality of number, a plurality of Ra′s are identical or different, a plurality of Rb′s are identical or different, a plurality of Re's are identical or different, and a plurality of Rd′s are identical or different,
• RA′—C≡C—RB′— (a′)
• wherein in the formula (a′),
• RA′ represents a hydrogen atom, an aryl group, or an alkyl group unsubstituted or substituted with at least one of a hydroxy group and an aryl group;
• and
• RB′ represents a single bond or an arylene group,
• wherein a part or all of hydrogen atoms on an aromatic ring of the aryl group and the arylene group are unsubstituted or substituted with a halogen atom, a hydroxy group, an amino group, a sulfanyl group, or a monovalent organic group having 1 to 20 carbon atoms and not comprising an aromatic ring, and
• wherein at least one of three RA′s in the compound represents a hydrogen atom.