Radiation-sensitive composition, method for forming pattern, polymer, and compound

A polymer comprising a structural unit (I) represented by formula (1):

• wherein in the formula (1),
• R1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group;
• L1 is a single bond or a divalent linking group;
• Ar represents a furan ring, a thiophene ring, or an aromatic heterocycle having 9 to 20 ring members comprising a furan ring or a thiophene ring;
• R2 is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms;
• R3 is a halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, a thiol group, or a monovalent organic group having 1 to 20 carbon atoms;
• n is an integer of 0 to 4;
• and when n is 2 or more, a plurality of R3s are identical to or different from each other.

A compound represented by formula (1-1):

• wherein in the formula (1-1),
• X represents —S— or —O—;
• R1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group;
• L1 is a single bond or a divalent linking group;
• R21 is an acid-dissociable group represented by a following formula (2-1), provided that when X is —S—, a total number of carbon atoms of L1 and R21 is 5 or more:
• wherein in the formula (2-1),
• R44 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms;
• R45 and R46 each independently represent a monovalent organic group having 1 to 10 carbon atoms, or R45 and R46 taken together represent a divalent alicyclic group or heterocyclic group having 3 to 10 ring members together with the carbon atom to which R45 and R46 are bonded,
• provided that when R44, R45, or R46 has a double bond other than an aromatic ring, two carbon atoms composing the double bond are bonded to 0, 2, or 3 hydrogen atoms in total;
• and
• * represents a bond bonded to an oxygen atom,
• R3 is a halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, a thiol group, or a monovalent organic group having 1 to 20 carbon atoms;
• n1 is an integer of 0 to 2;
• and when n1 is 2, two R3s are identical to or different from each other.

A compound represented by formula (1-2-1) or formula (1-2-2):

• wherein in the formula (1-2-1) and the formula (1-2-2),
• X represents —S— or —O—;
• R1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group;
• R22 is an acid-dissociable group represented by a following formula (2-2), provided that a number of carbon atoms of R22 is 6 or more:
• wherein in the formula (2-2),
• R47 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms;
• R48 and R49 each independently represent a monovalent organic group having 1 to 10 carbon atoms, or R48 and R49 taken together represent a divalent alicyclic group or heterocyclic group having 3 to 10 ring members other together with the carbon atom to which R48 and R49 are bonded,
• provided that when R47, R48, or R49 has a double bond other than a double bond of an aromatic ring, two carbon atoms bonded by the double bond are bonded to 0, 1, or 3 hydrogen atoms in total;
• and
• * represents a bond bonded to an oxygen atom,
• R3 is a halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, a thiol group, or a monovalent organic group having 1 to 20 carbon atoms;
• n is an integer of 0 to 4;
• and when n is 2 or more, a plurality of R3s are identical to or different from each other.

A compound represented by formula (1-3):

• wherein in the formula (1-3),
• X represents —S— or —O—;
• R1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group;
• R23 is a monovalent organic group having 3 or more carbon atoms;
• R3 is a halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, a thiol group, or a monovalent organic group having 1 to 20 carbon atoms;
• n is an integer of 0 to 4;
• and when n is 2 or more, a plurality of R3s are identical to or different from each other.

A compound represented by formula (1-4):

• wherein in the formula (1-4),
• X represents —S— or —O—;
• R1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group;
• LM1 is a divalent linking group;
• R24 is a group represented by a following formula (2-3):
• wherein in the formula (2-3),
• R50 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms;
• R51 and R52 each independently represent a monovalent organic group having 1 to 10 carbon atoms, or R51 and R52 taken together represent a divalent alicyclic group or heterocyclic group having 3 to 10 ring members together with the carbon atom to which R51 and R52 are bonded;
• and
• * represents a bond bonded to an oxygen atom,
• R3 is a halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, a thiol group, or a monovalent organic group having 1 to 20 carbon atoms;
• n is an integer of 0 to 4;
• and when n is 2 or more, a plurality of R3s are identical to or different from each other.

A compound represented by formula (1-5):

• wherein in the formula (1-5),
• X represents —S— or —O—;
• R1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group;
• LM2 is a divalent linking group, provided that when m=0 and X is —O—, LM2 is a group represented by formula (3):
• wherein in the formula (3),
• Y1 and Y2 are each independently a single bond, —O—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, or —S—;
• Z is a divalent hydrocarbon group having 1 to 10 carbon atoms, provided that when p is 0, Y1 is —O—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, or —S—;
• p is an integer of 0 to 2;
• and
• * represents a bond bonded to a carbon atom of the vinyl group in the formula (1-5), and ** represents a bond bonded to a carbon atom of the heterocyclic ring in the formula (1-5),
• R3 is a halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, a thiol group, or a monovalent organic group having 1 to 20 carbon atoms;
• m is 0 or 1;
• n is an integer of 0 to 4;
• and when n is 2 or more, a plurality of R3s are identical to or different from each other.