Composition, method of forming resist underlayer film, and method of forming resist pattern

A method of forming a resist underlayer film, the method comprising:

• applying a composition for resist underlayer film formation directly or indirectly on a substrate to form the resist underlayer film,
• wherein the composition for resist underlayer film formation comprises:
• a compound comprising an aromatic ring;
• and
• a first polymer comprising a first structural unit represented by formula (1) and a second structural unit represented by formula (2), wherein
• a content of the first polymer with respect to 100 parts by mass of the compound is no less than 0.1 parts by mass and no greater than 200 parts by mass,
• wherein,
• in the formula (1), R1 represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms;
• and R2 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, a part or all hydrogen atoms of the monovalent hydrocarbon group being substituted with a fluorine atom, and
• in the formula (2), R3 represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms;
• L represents a single bond or a divalent linking group;
• Ar represents a group obtained by removing (n+1) hydrogen atoms from a substituted or unsubstituted aromatic ring having 6 to 20 ring atoms;
• R4 represents a monovalent hydroxyalkyl group having 1 to 10 carbon atoms;
• and n is an integer of 1 to 8, wherein in a case in which n is no less than 2, a plurality of R4s are identical or different.

A method of forming a resist pattern, the method comprising:

• applying a composition for resist underlayer film formation directly or indirectly on a substrate to form a resist underlayer film;
• applying a composition for resist film formation directly or indirectly on the resist underlayer film to form a resist film;
• exposing the resist film to a radioactive ray;
• and
• developing the resist film exposed,
• wherein the composition for resist underlayer film formation comprises:
• a compound comprising an aromatic ring;
• and
• a first polymer comprising a first structural unit represented by formula (1) and a second structural unit represented by formula (2), wherein
• a content of the first polymer with respect to 100 parts by mass of the compound is no less than 0.1 parts by mass and no greater than 200 parts by mass,
• wherein,
• in the formula (1), R1 represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms;
• and R2 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, a part or all hydrogen atoms of the monovalent hydrocarbon group being substituted with a fluorine atom, and
• in the formula (2), R3 represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms;
• L represents a single bond or a divalent linking group;
• Ar represents a group obtained by removing (n+1) hydrogen atoms from a substituted or unsubstituted aromatic ring having 6 to 20 ring atoms;
• R4 represents a monovalent hydroxyalkyl group having 1 to 10 carbon atoms;
• and n is an integer of 1 to 8, wherein in a case in which n is no less than 2, a plurality of R4s are identical or different.