JP5677670B2 - Resin, photoresist composition and method for producing resist pattern - Google Patents

Description

  The present invention relates to a resin, a photoresist composition, and a method for producing a resist pattern.

  As a resin for a photoresist composition used for microfabrication of a semiconductor using a lithography technique, for example, Patent Document 1 includes 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate, and α. A resin having a structural unit derived from methacryloyloxy-γ-butyrolactone is described.

JP 2006-257078 A

  In a conventional photoresist composition containing a resin, the resolution, focus margin, and exposure margin of the pattern to be obtained may not always be satisfactory.

The present invention includes the following inventions.
[1] A resin having a structural unit derived from a compound represented by formula (I) and a structural unit derived from a compound represented by formula (II).
[In the formula (I),
R ¹ represents a hydrogen atom, a halogen atom or a C ₁ -C ₆ alkyl group which may have a halogen atom.
X ¹ represents a C _{2 to} C ₃₆ heterocyclic group, and a hydrogen atom contained in the heterocyclic group is a halogen atom, a hydroxyl group, a C _{1 to} C ₂₄ hydrocarbon group, a C _{1 to} C ₁₂ alkoxy group, or C _2. -C ₄ acyl group or _C 2 -C ₄ may be substituted with an acyloxy group, -CH contained in the heterocyclic group ₂ - may be replaced by -CO- or -O-. ]
[In the formula (II),
R ³¹ represents a C ₁ -C ₆ alkyl group which may have a hydrogen atom, a halogen atom or a halogen atom.
Z ¹ represents a divalent C _{1 to} C ₁₇ saturated hydrocarbon group, and —CH ₂ — contained in the saturated hydrocarbon group is —CO—, —O—, —S—, or —N (R ³² )-May be replaced.
R ³² represents a hydrogen atom or a C ₁ -C ₆ alkyl group.
T represents a heterocyclic group containing —SO ₂ — in the skeleton, and the hydrogen atom contained in the heterocyclic group is a halogen atom, a hydroxyl group, a C ₁ -C ₁₂ alkyl group, a C ₁ -C ₁₂ alkoxy group, C ₆ -C ₁₂ aryl _group, C 7 _{-C 13} aralkyl group may be substituted with a glycidyl group or a _C 2 -C ₄ acyl group, -CH contained in the heterocyclic group ₂ -, -CO- , —O—, —S—, —SO ₂ — or —N (R ³³ ) — may be substituted.
R ³³ represents a hydrogen atom or a C ₁ -C ₆ alkyl group. ]

[2] The resin according to [1], wherein the compound represented by the formula (I) is a compound represented by the formula (III).
[In the formula (III),
R ² represents a C _{1 to} C ₆ alkyl group which may have a hydrogen atom, a halogen atom or a halogen atom.
R ^{3 to} R ⁸ each independently represents a hydrogen atom or a C _{1 to} C ₂₄ hydrocarbon group, or at least two selected from R ^{3 to} R ⁸ are bonded to each other to form a ring of C _{3 to} C ₃₀ . It is formed and hydrogen atoms contained in the hydrocarbon group and the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _group, C 2 -C ₄ acyl group or a _C 2 ~ It may be substituted with a C ₄ acyloxy group, and —CH ₂ — contained in the hydrocarbon group and the ring may be replaced with —CO— or —O—.
t1 represents an integer of 0 to 3. ]

[3] The resin according to [1] or [2], wherein the compound represented by the formula (I) is a compound represented by the formula (IV).
[In the formula (IV),
R ⁹ represents a hydrogen atom, a halogen atom or a C ₁ -C ₆ alkyl group which may have a halogen atom.
R ^{10 to} R ¹⁹ each independently represents a hydrogen atom or a C _{1 to} C ₁₂ hydrocarbon group, or at least two selected from R ^{10 to} R ¹⁹ are bonded to each other to form a ring of C _{3 to} C ₂₄ . It is formed and hydrogen atoms contained in the hydrocarbon group and the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _group, C 2 -C ₄ acyl group or a _C 2 ~ It may be substituted with a C ₄ acyloxy group, and —CH ₂ — contained in the hydrocarbon group and the ring may be replaced with —CO— or —O—.
t2 and t3 each independently represents an integer of 0 to 3. ]

[4] The resin according to any one of [1] to [3], wherein the compound represented by the formula (I) is a compound represented by the formula (V).
[In the formula (V),
R ²⁰ represents a C ₁ -C ₆ alkyl group which may have a hydrogen atom, a halogen atom or a halogen atom.
R ²¹ represents a halogen atom, a hydroxyl group, a C _{1 to} C ₁₂ alkyl group, a C _{1 to} C ₁₂ alkoxy group, a C _{2 to} C ₄ acyl group, or a C _{2 to} C ₄ acyloxy group.
t4 represents an integer of 0 to 8. ]

  [5] The resin according to any one of [1] to [4], wherein T is a group having a norbornane skeleton.

[6] The resin according to any one of [1] to [5], wherein T is a group represented by the formula (T3).
[In the formula (T3),
Hydrogen atoms contained in the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _groups, C 6 _{-C 12} aryl _group, C 7 _{-C 13} aralkyl group, glycidoxy group or _{C 2} It may be substituted with -C ₄ acyl group, _-CH 2 contained in the ring - is, -CO -, - O -, - S -, - SO 2 - or -N ^{(R 33)} - in has been replaced May be.
R ³³ represents a hydrogen atom or a C ₁ -C ₆ alkyl group.
* Represents a bond. ]

  [7] The resin according to any one of [1] to [6], further having an acid labile group, insoluble or hardly soluble in an alkaline aqueous solution, and capable of dissolving in an alkaline aqueous solution by acting with an acid .

  [8] A photoresist composition comprising the resin according to any one of [1] to [7] and an acid generator.

[9] The photoresist composition according to [8], wherein the acid generator is an acid generator represented by the formula (B1).
[In Formula (B1), Q ¹ and Q ² each independently represent a fluorine atom or a C ₁ -C ₆ perfluoroalkyl group.
L ^b1 represents a single bond or a divalent C _{1 to} C ₁₇ saturated hydrocarbon group, and —CH ₂ — of the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Y represents a C _{1 to} C ₁₈ aliphatic hydrocarbon group which may have a substituent or a C _{3 to} C ₁₈ saturated cyclic hydrocarbon group which may have a substituent, and the aliphatic hydrocarbon —CH ₂ — contained in the group and the saturated cyclic hydrocarbon group may be replaced by —O—, —SO ₂ — or —CO—.
Z ⁺ represents an organic cation. ]

[10] The photoresist composition according to [9], wherein L ^b1 is * —CO—O— (* represents a bond with —C (Q ¹ ) (Q ² ) —).

[11] The photoresist composition according to [9] or [10], wherein Z ⁺ is an arylsulfonium cation.

  [12] The photoresist composition according to any one of [8] to [11], which contains a basic compound.

[13] (1) A step of applying the photoresist composition according to any one of [8] to [12] on a substrate,
(2) a step of removing the solvent from the composition after coating to form a composition layer;
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) A pattern forming method including a step of developing the heated composition layer using a developing device.

  According to the resin of the present invention, a pattern having excellent resolution, focus margin and exposure margin can be formed using a photoresist composition containing the resin.

In this specification, unless otherwise specified, examples of each substituent are applied to any chemical structural formula having the same substituent while appropriately selecting the number of carbon atoms. Those which can be linear, branched or cyclic include any of them, and they may be mixed. Each substituent can be a monovalent or divalent or higher substituent depending on the binding site. When stereoisomers exist, all stereoisomers are included.
Further, "(meth) acrylic monomer" means at least one monomer having a structure of "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- ". Similarly, “(meth) acrylate” and “(meth) acrylic acid” mean “at least one of acrylate and methacrylate” and “at least one of acrylic acid and methacrylic acid”, respectively.

<Resin (hereinafter sometimes referred to as “resin (A)”)>
The resin of the present invention has a structural unit derived from the compound represented by formula (I) and a structural unit derived from the compound represented by formula (II).

<Compound represented by formula (I)>
[In the formula (I),
R ¹ represents a hydrogen atom, a halogen atom or a C ₁ -C ₆ alkyl group which may have a halogen atom.
X ¹ represents a C _{2 to} C ₃₆ heterocyclic group, and a hydrogen atom contained in the heterocyclic group is a halogen atom, a hydroxyl group, a C _{1 to} C ₂₄ hydrocarbon group, a C _{1 to} C ₁₂ alkoxy group, or C _2. -C ₄ acyl group or _C 2 -C ₄ may be substituted with an acyloxy group, -CH contained in the heterocyclic group ₂ - may be replaced by -CO- or -O-. ]

The structural unit derived from the compound represented by the formula (I) is the following structural unit.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group.

  Examples of the alkyl group which may have a halogen atom include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, A perfluorohexyl group etc. are mentioned.

Any heterocyclic group may be used as long as it contains —CO— and a nitrogen atom, and may be an aromatic heterocyclic ring or may have no aromaticity. Moreover, any of monocyclic and polycyclic may be sufficient.
Specific examples include the following.

In addition, examples of the group in which —CH ₂ — contained in the heterocyclic ring is replaced by —O— include the following.

As a hydrocarbon group, any of an aliphatic hydrocarbon group, a saturated cyclic hydrocarbon group, and an aromatic hydrocarbon group may be sufficient. For example, as the aliphatic hydrocarbon group, methyl group, ethyl group, n-propyl group, 1-methylethyl group (isopropyl group), n-butyl group, 1,1-dimethylethyl group (tert-butyl group), 2 , 2-dimethylethyl group, sec-butyl group, 1-methylpropyl group, 2,2-dimethylpropyl group, n-pentyl group, 1-ethylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl Group, n-hexyl group, 1-propylbutyl group, 1-methylpentyl group, 1,4-dimethylhexyl group, heptyl group, 1-methylheptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, Alkyl groups such as undecyl group and dodecyl group; as saturated cyclic hydrocarbon group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl Group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group and other cycloalkyl groups, norbornyl group, 1-adamantyl group, 2-adamantyl group, isobornyl group, etc .; aromatic hydrocarbon group such as phenyl group, naphthyl group Anthranyl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, biphenyl group, anthryl group, phenanthryl group, 2,6-diethyl Aryl groups such as phenyl group and 2-methyl-6-ethylphenyl; and the like. Moreover, the combination of these groups may be sufficient.
The hydrocarbon _group, C 1 _{-C 12} alkyl group are preferable.

As an alkoxy group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, an n-hexoxy group, a heptoxy group, an octoxy group , 2-ethylhexoxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group and the like.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.

In the formula (I), R ¹ is preferably a hydrogen atom or a methyl group.
X ¹ represents a 4-6 membered heterocyclic group containing a nitrogen atom or a heterocyclic ring containing such a 4-6 membered ring (eg, preferably 4-20 membered, more preferably 4-16 membered polycyclic ring). Or a polycyclic bridged ring). -CO- is preferably arranged at a position adjacent to the nitrogen atom.

The compound represented by the formula (I) is preferably a compound represented by the formula (III).
[In the formula (III),
R ² represents a C _{1 to} C ₆ alkyl group which may have a hydrogen atom, a halogen atom or a halogen atom.
R ^{3 to} R ⁸ each independently represents a hydrogen atom or a C _{1 to} C ₂₄ hydrocarbon group, or at least two selected from R ^{3 to} R ⁸ are bonded to each other to form a ring of C _{3 to} C ₃₀ . It is formed and hydrogen atoms contained in the hydrocarbon group and the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _group, C 2 -C ₄ acyl group or a _C 2 ~ It may be substituted with a C ₄ acyloxy group, and —CH ₂ — contained in the hydrocarbon group and the ring may be replaced with —CO— or —O—.
t1 represents an integer of 0 to 3. ]

The compound represented by formula (I) is preferably a compound represented by formula (IV).
[In the formula (IV),
R ⁹ represents a hydrogen atom, a halogen atom or a C ₁ -C ₆ alkyl group which may have a halogen atom.
R ^{10 to} R ¹⁹ each independently represents a hydrogen atom or a C _{1 to} C ₁₂ hydrocarbon group, or at least two selected from R ^{10 to} R ¹⁹ are bonded to each other to form a ring of C _{3 to} C ₂₄ . It is formed and hydrogen atoms contained in the hydrocarbon group and the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _group, C 2 -C ₄ acyl group or a _C 2 ~ It may be substituted with a C ₄ acyloxy group, and —CH ₂ — contained in the hydrocarbon group and the ring may be replaced with —CO— or —O—.
t2 and t3 each independently represents an integer of 0 to 3. ]

In formula (III) and formula (IV), examples of the ring formed by combining two of R ^{3 to} R ⁸ or R ^{10 to} R ¹⁹ include saturated cyclic hydrocarbons and the above-described heterocyclic rings.
t1 is preferably 0 or 1, and more preferably 0.
t2 is preferably 0 or 1, more preferably 0.
t3 is preferably 1 or 2, and more preferably 1.

The compound represented by the formula (I) is preferably a compound represented by the formula (V).
[In the formula (V),
R ²⁰ represents a C ₁ -C ₆ alkyl group which may have a hydrogen atom, a halogen atom or a halogen atom.
R ²¹ represents a halogen atom, a hydroxyl group, a C _{1 to} C ₁₂ alkyl group, a C _{1 to} C ₁₂ alkoxy group, a C _{2 to} C ₄ acyl group, or a C _{2 to} C ₄ acyloxy group.
t4 represents an integer of 0 to 8. ]
t4 is preferably 0 or 1, and more preferably 0.

Examples of the compound represented by the formula (I) include the following compounds.

The compound represented by the formula (I) can be produced by a method known in the art, and examples thereof include the following production methods.
A compound represented by the formula (I) can be obtained by reacting a compound represented by the formula (Ia) and a compound represented by the formula (Ib) in a solvent under a catalyst. it can. Here, as a catalyst, N-methylpyrrolidine is preferable. As the solvent, dimethylformamide is preferable.

[Wherein, X ¹ and R ¹ represent the same meaning as described above.
X represents a halogen atom or a (meth) acryloyloxy group. ]

Among them, a chlorine atom is preferable as the halogen atom.
Examples of the compound represented by the formula (Ia) include the following compounds. These compounds can use what is marketed.

For example, the compound represented by the formula (I-a-1) can be obtained by a reaction of cyclopentene and chlorosulfonyl isocyanate (refer to JP-T-2007-514775).

  Examples of the compound represented by the formula (Ib) include methacrylic acid chloride and methacrylic anhydride.

<Compound represented by formula (II)>
[In the formula (II),
R ³¹ represents a C ₁ -C ₆ alkyl group which may have a hydrogen atom, a halogen atom or a halogen atom.
Z ¹ represents a divalent C _{1 to} C ₁₇ saturated hydrocarbon group, and —CH ₂ — contained in the saturated hydrocarbon group is —CO—, —O—, —S—, or —N (R ³² )-May be replaced.
R ³² represents a hydrogen atom or a C ₁ -C ₆ alkyl group.
T represents a heterocyclic group containing —SO ₂ — in the skeleton, and the hydrogen atom contained in the heterocyclic group is a halogen atom, a hydroxyl group, a C ₁ -C ₁₂ alkyl group, a C ₁ -C ₁₂ alkoxy group, C ₆ -C ₁₂ aryl _group, C 7 _{-C 13} aralkyl group may be substituted with a glycidyl group or a _C 2 -C ₄ acyl group, -CH contained in the heterocyclic group ₂ -, -CO- , —O—, —S—, —SO ₂ — or —N (R ³³ ) — may be substituted.
R ³³ represents a hydrogen atom or a C ₁ -C ₆ alkyl group. ]

The structural unit derived from the compound represented by the formula (II) is the following structural unit.

R ³¹ may be the same as R ^1, and is preferably a hydrogen atom or a methyl group.

Examples of the divalent saturated hydrocarbon group include an alkylene group (alkanediyl group) and a group containing a divalent saturated cyclic hydrocarbon.
Examples of the alkylene group include methylene group, ethylene group, propylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl. Group, hexane-1,6-diyl group, heptane-1,7-diyl group and the like.
Examples of the divalent group containing a divalent saturated cyclic hydrocarbon group include groups represented by formulas (Z1) to (Z3).
[In Formula (Z1)-Formula (Z3),
Z ^A and Z ^B each independently represent a single bond or a C ₁ -C ₆ alkylene group. However, carbon number of the group represented by Formula (Z1)-Formula (Z3) is 1-17. ]

Z ¹ is preferably a group in which —CH ₂ — contained in a divalent saturated hydrocarbon group is replaced by —O—, —CO—, —S— or —N (R ³² ) —. In particular, the divalent saturated hydrocarbon group is preferably an alkylene group. R ³² is preferably a hydrogen atom.
For ^{example, -O-X 11 -, -} X 11 -O -, - X 11 -CO-O -, - X 11 -O-CO -, - X 11 -O-X 12 -, - NH-X 11 - , ^-X 11 -NH- and the like, preferably ^{-O-X 11 -, - X} 11 -O -, - X 11 -CO-O -, - NH-X 11 -, - X 11 -NH- and the like, more preferably ^{-O-X 11 -, - NH} -X 11 - , and the like. In particular, it is more preferable that Z ¹ is —O—CH ₂ —.
^{Here, X 11} and ^{X 12} each independently represent a single bond or a _C 1 _{-C 15} alkylene group. However, in the group in which —CH ₂ — contained in the alkylene group is replaced by —O—, —CO—, —S— or —N (R ³² ) —, the number of atoms constituting the main chain of each of the above groups 1 to 17 is suitable, 1 to 10 is preferable, and 1 to 5 is more preferable.

Examples of the group having a heterocyclic group containing —SO ₂ — in the skeleton include _2- to 20-membered aromatic or non-aromatic monocyclic, polycyclic or bridged rings.
Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, trityl group, naphthylmethyl group, naphthylethyl group and the like.
Examples of the group in which —CH ₂ — contained in the heterocyclic group containing —SO ₂ — in the skeleton is replaced by —O— etc. are replaced by —O—, —CO—, —O— and —CO—. Group.

In the formula (II), T is preferably a group containing —SO ₂ — in the norbornane skeleton, for example, more preferably a group represented by the formula (T1). It is more preferable that it is group represented by.
[In Formula (T1) and Formula (T2),
At least one —CH ₂ — contained in the ring is replaced by —SO ₂ —, and is further replaced by —CO—, —O—, —S—, —SO ₂ — or —N (R ³³ ) —. even if well, hydrogen atoms contained in the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _groups, C 6 _{-C 12} aryl _group, C 7 _{-C 13} aralkyl group, it may be substituted with a glycidoxy group or a C ₂ -C ₄ acyl group. R ³³ represents a hydrogen atom or a C ₁ -C ₆ alkyl group.
* Represents a bond. ]

Furthermore, the group represented by the formula (T3) is more preferable, and the group represented by the formula (T4) is more preferable.
[In Formula (T3) and Formula (T4),
Hydrogen atoms contained in the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _groups, C 6 _{-C 12} aryl _group, C 7 _{-C 13} aralkyl group, glycidoxy group or _{C 2} It may be substituted with -C ₄ acyl group, _-CH 2 contained in the ring - is, -CO -, - O -, - S -, - SO 2 - or -N ^{(R 33)} - in has been replaced May be.
R ³³ and * have the same meaning as described above. ]

Examples of T include the following. * Indicates a bond with an oxygen atom.

Examples of the compound represented by the formula (II) include the following compounds.

The compound represented by the formula (II) can be produced by a method known in the art.
For example, ^{Z 1} is -O-CH ₂ - Examples of those compounds include the following manufacturing method.
The compound represented by the formula (II-c) is obtained by reacting the compound represented by the formula (II-a) with the compound represented by the formula (II-b) in the presence of a basic catalyst. be able to. Examples of the base catalyst include pyridine. Examples of the solvent include tetrahydrofuran.
The compound represented by the formula (II) is obtained by reacting the compound represented by the formula (II-c) and the compound represented by the formula (II-d) in a solvent under a catalyst. Can be obtained. Here, N-methylpyrrolidine etc. are mentioned as a catalyst. Examples of the solvent include dimethylformamide.
[Wherein T and R ³¹ represent the same meaning as described above.
X ¹ and X ² each independently represent a halogen atom. X ³ represents a halogen atom or a (meth) acryloyloxy group. ]

As the halogen atom, a chlorine atom is preferable.
Examples of the compound represented by the formula (II-a) include 5-hydroxy-3-oxa-2-thiatricyclo [4.2.1.0 ^4,8 ] nonane described in JP-A-2007-119696. 2,2-dione and the like can be mentioned.
Examples of the compound represented by the formula (II-b) include chloroacetyl chloride.
Examples of the compound represented by the formula (II-d) include methacrylic acid chloride and methacrylic anhydride.

The molar ratio of the content of the structural unit derived from the compound represented by formula (I) and the structural unit derived from the compound represented by formula (II) in the resin is usually 1: 0.2 to 1:10 mol. %, Preferably 1: 0.4 to 1: 8 mol%, more preferably 1: 0.5 to 1: 5 mol%.
The total content of the structural unit derived from the compound represented by the formula (I) and the structural unit derived from the compound represented by the formula (II) in the resin is usually 5 to 100 mol% in all the units of the resin. Preferably, it is 10-70 mol%, More preferably, it is 15-50 mol%.

  In addition to the structural unit derived from the compound represented by formula (I) and the structural unit derived from the compound represented by formula (II), the resin preferably further has an acid-labile group, It is a resin that is insoluble or hardly soluble in an alkaline aqueous solution, and the resin that has reacted with an acid is preferably a resin that can be dissolved in an alkaline aqueous solution.

  A resin that becomes alkali-soluble by the action of an acid can be produced by polymerizing a monomer having an acid-labile group (hereinafter sometimes referred to as “monomer having an acid-labile group (a1)”). The phrase “becomes soluble in an alkali by the action of an acid” means “being insoluble or hardly soluble in an alkaline aqueous solution before contact with an acid, but soluble in an alkaline aqueous solution after contact with an acid”. . As the monomer (a1) having an acid labile group, one type may be used alone, or two or more types may be used in combination.

<Monomer (a1) having an acid labile group>
The “acid-labile group” means a group that cleaves a leaving group upon contact with an acid to form a hydrophilic group (for example, a hydroxy group or a carboxy group). Examples of the acid labile group include an alkoxycarbonyl group represented by the formula (1) in which —O— is bonded to a tertiary carbon atom (excluding a bridgehead carbon atom of a bridged cyclic hydrocarbon group) (ie, Ester bond having a tertiary alcohol residue). Hereinafter, the group represented by the formula (1) may be referred to as “acid-labile group (1)”.

In formula (1), R ^{a1 to} R ^a3 each independently represents an aliphatic hydrocarbon group or a saturated cyclic hydrocarbon group, or R ^a1 and R ^a2 may be bonded to each other to form a ring. Good. * Represents a bond.

Examples of the acid labile group (1) include:
1,1-dialkylalkoxycarbonyl group (in the group (1), wherein R ^{a1 to} R ^a3 are alkyl groups, preferably a tert-butoxycarbonyl group),
2-alkyl-2-adamantyloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom form an adamantyl group and R ^a3 is an alkyl group), and 1- (1-adamantyl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

  The monomer (a1) having an acid labile group is preferably a monomer having an acid labile group (1) and a carbon-carbon double bond, more preferably an acid labile group (1). (Meth) acrylic monomer having

Among the (meth) acrylic monomers having the acid-labile group (1), those having a C _{5 to} C ₂₀ saturated cyclic hydrocarbon group are preferred. If a resin obtained by polymerizing the monomer (a1) having a bulky structure such as a saturated cyclic hydrocarbon group is used, the resolution can be improved.
The saturated cyclic hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic saturated cyclic hydrocarbon group include a cycloalkyl group (for example, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group). Examples of the polycyclic saturated cyclic hydrocarbon group include a group obtained by hydrogenating a condensed aromatic hydrocarbon group (for example, a hydronaphthyl group), a bridged cyclic hydrocarbon group (for example, an adamantyl group, a norbornyl group), and the like. . In addition, a group having a shape in which a bridged ring (for example, norbornane ring) and a single ring (for example, cycloheptane ring or cyclohexane ring) or a polycycle (for example, decahydronaphthalene ring) are condensed, or A group having a condensed shape is also included in the saturated cyclic hydrocarbon group.

  Among the (meth) acrylic monomers having the acid labile group (1) and the saturated cyclic hydrocarbon group, the acid labile group represented by the formula (a1-1) or the formula (a1-2) Monomers having are preferred. These may be used alone or in combination of two or more.

In formula (a1-1) and formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or —O— (CH ₂ ) _k1 —CO—O—, and k1 represents an integer of 1 to 7. However, —O— and the like enumerated for L ^a1 and L ^a2 are respectively bonded to —CO— of the formula (a1-1) and the formula (a1-2) on the left side, and to an adamantyl group or cyclohexyl group on the right side. Means to join.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent a C _{1 to} C ₈ aliphatic hydrocarbon group or a C _{3 to} C ₁₀ saturated cyclic hydrocarbon group.
m1 represents an integer of 0 to 14, and n1 represents an integer of 0 to 10.

In the formula (a1-1) and the formula (a1-2), L ^a1 and L ^a2 are preferably, -O- or _{-O- (CH 2) f1 -CO-} O- and is (wherein f1 is 1 to 4), and more preferably -O-.
R ^a4 and R ^a5 are preferably methyl groups.
The carbon number of the aliphatic hydrocarbon group of R ^a6 and R ^a7 is preferably 6 or less, and the carbon number of the saturated cyclic hydrocarbon group is preferably 8 or less, more preferably 6 or less.
Examples of the aliphatic hydrocarbon group for R ^a6 and R ^a7 include a methyl group, an ethyl group, a 1-methylethyl group (isopropyl group), a 1,1-dimethylethyl group (tert-butyl group), 2,2- Dimethylethyl group, propyl group, 1-methylpropyl group, 2,2-dimethylpropyl group, 1-ethylpropyl group, butyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-propylbutyl group , A pentyl group, 1-methylpentyl group, hexyl group, 1,4-dimethylhexyl group, heptyl group, 1-methylheptyl group, octyl group and the like are preferable. As the saturated cyclic hydrocarbon group for R ^a6 and R ^a7 , for example, a cycloheptyl group, a methylcycloheptyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a norbornyl group, a methylnorbornyl group, and the like are preferable.

  m1 is preferably an integer of 0 to 3, more preferably 0 or 1. n1 is 0, preferably an integer of 0 to 3, more preferably 0 or 1. k1 is preferably an integer of 1 to 4, more preferably 1.

Examples of the monomer (a1-1) having an adamantyl group include the following.

Among these, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, and 2-isopropyl-2-adamantyl (meth) acrylate are preferable, and those in the form of methacrylate are more preferable. .

Examples of the monomer (a1-2) having a cyclohexyl group include the following.
Among these, 1-ethyl-1-cyclohexyl (meth) acrylate is preferable, and 1-ethyl-1-cyclohexyl methacrylate is more preferable.

  The content of the structural unit derived from the monomer represented by the formula (a1-1) or the formula (a1-2) in the resin is usually 10 to 95 mol%, preferably 10 to 90, in all units of the resin. It is mol%, More preferably, it is 50-85 mol%.

  Examples of the monomer having an acid labile group (1) and a carbon-carbon double bond include a monomer having a norbornene ring represented by the formula (a1-3). Since the resin having a structural unit derived from the monomer (a1-3) having an acid labile group has a bulky structure, the resolution can be improved. Furthermore, the monomer (a1-3) having an acid labile group can improve the resistance to dry etching of a resist by introducing a rigid norbornane ring into the main chain of the resin.

In formula (a1-3),
R ^a9 represents a hydrogen atom, a C ₁ -C ₃ aliphatic hydrocarbon group ^optionally having a substituent (for example, a hydroxy group), a carboxy group, a cyano group, or a group —COOR ^a13 , and R ^a13 represents C ₁ -C ₈ represents an aliphatic hydrocarbon group or a C ₃ -C ₈ saturated cyclic hydrocarbon group, a hydrogen atom of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be substituted with a hydroxy group, In the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group, —CH ₂ — may be replaced by —O— or —CO—.
R ^{a10 to} R ^a12 each independently represent a C _{1 to} C ₁₂ aliphatic hydrocarbon group or a C _{3 to} C ₁₂ saturated cyclic hydrocarbon group, or R ^a10 and R ^a11 are bonded to each other to form a ring. The aliphatic hydrocarbon group and the hydrogen atom of the saturated cyclic hydrocarbon group may be substituted with a hydroxy group or the like, and —CH of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group _2- may be replaced by -O- or -CO-.

Examples of the aliphatic hydrocarbon group which may have a substituent for R ^a9 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a 2-hydroxyethyl group.
^Examples of R ^a13 include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group, and a 2-oxo-oxolan-4-yl group.

Examples of R ^{a10 to} R ^a12 include a methyl group, an ethyl group, a cyclohexyl group, a methylcyclohexyl group, a hydroxycyclohexyl group, an oxocyclohexyl group, and an adamantyl group.
Examples of the saturated cyclic hydrocarbon group formed by R ^a10 , R ^a11 and the carbon to which they are bonded include a cyclohexyl group and an adamantyl group.

  Examples of the monomer (a1-3) having a norbornene ring include, for example, 5-norbornene-2-carboxylic acid-tert-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, 5-norbornene-2 -1-methylcyclohexyl carboxylate, 2-methyl-2-adamantyl 5-norbornene-2-carboxylate, 2-ethyl-2-adamantyl 5-norbornene-2-carboxylate, 5-norbornene-2-carboxylic acid 1- (4-methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl-1- (4 -Oxocyclohexyl) ethyl, 5-norbornene-2-carboxylic acid 1- (1-adap Pentyl) -1-methylethyl and the like.

  The content of the structural unit derived from the monomer represented by the formula (a1-3) in the resin is usually 10 to 95 mol%, preferably 10 to 90 mol%, more preferably in all units of the resin. Is 50 to 85 mol%.

Examples of the monomer having an acid labile group (1) and a carbon-carbon double bond include monomers represented by the formula (a1-4).
In formula (a1-4),
R ^{10 ′} represents a hydrogen atom, a halogen atom, or a C _{1 to} C ₆ alkyl group which may have a halogen atom.
R ^{11 ′} is independently a halogen atom, a hydroxyl group, a C ₁ -C ₆ alkyl group, a C ₁ -C ₆ alkoxy group, a C ₂ -C ₄ acyl group, a C ₂ -C ₄ acyloxy group, an acryloyl group or a methacryloyl group. Represents a group.
l ^a represents an integer of 0 to 4; If l ^a is an integer of 2 or more, plural R ^{11 'may} be the same, even the type of groups of different types of groups.
R ^{12 ′} and R ^{13 ′} each independently represents a hydrogen atom or a C ₁ -C ₁₂ hydrocarbon group.
X ^a2 represents a C _{1 to} C ₁₇ saturated hydrocarbon group which may have a single bond or a substituent, and —CH ₂ — contained in the saturated hydrocarbon group represents —CO—, —O—, — S—, —SO ₂ — or —N (R ^c ) — may be substituted. R ^c is a hydrogen atom or a C ₁ -C ₆ alkyl group.
Y ^a3 is a C _{1 to} C ₁₂ aliphatic hydrocarbon group, a C _{3 to} C ₁₈ saturated cyclic hydrocarbon group or a C _{6 to} C ₁₈ aromatic hydrocarbon group, and the aliphatic hydrocarbon group and saturated cyclic hydrocarbon The group and the aromatic hydrocarbon group may have a substituent.

In the formula (a1-4), examples of the alkyl group, particularly preferably C ₁ -C ₄ alkyl group, C ₁ -C more preferably ₂ alkyl group, a methyl group is particularly preferred.
The alkoxy group, particularly preferably C ₁ -C ₄ alkoxy group, more preferably C ₁ -C ₂ alkoxy group, a methoxy group is particularly preferred.
Examples of the C _{1 to} C ₁₂ hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, and an octyl group. 2-ethylhexyl group, cyclohexyl group, adamantyl group, 2-alkyl-2-adamantyl group, 1- (1-adamantyl) -1-alkyl group, isobornyl group and the like.

As a monomer (a1-4), the following monomers are mentioned, for example.

  The content of the structural unit derived from the monomer represented by the formula (a1-4) in the resin is usually 10 to 95 mol%, preferably 10 to 90 mol%, more preferably in all units of the resin. Is 50 to 85 mol%.

Examples of other acid labile monomers having an acid labile group (a) include the following monomers.

  The content of structural units derived from other acid labile monomers in the resin is usually 10 to 95 mol%, preferably 15 to 90 mol%, more preferably 20 to 85 mol% in all units of the resin. %.

The resin (A) is preferably a co-polymerization of a monomer (a1) having an acid labile group and a monomer having no acid labile group (hereinafter sometimes referred to as “acid stable monomer”). It is a coalescence. An acid stable monomer may be used individually by 1 type, and may use 2 or more types together.
When the resin (A) is a copolymer of a monomer (a1) having an acid labile group and an acid stable monomer, the structural units derived from the monomer (a1) having an acid labile group are all Preferably it is 10-80 mol% with respect to 100 mol% of structural units, More preferably, it is 20-60 mol%. Further, the structural unit derived from the monomer having an adamantyl group (particularly the monomer (a1-1) having an acid labile group) is added in an amount of 15 mol with respect to 100 mol% of the monomer (a1) having an acid labile group. % Or more is preferable. When the ratio of the monomer having an adamantyl group is increased, the dry etching resistance of the resist is improved.

<Acid stable monomer>
As the acid stable monomer, those having a hydroxy group or a lactone ring are preferred. Derived from an acid stable monomer having a hydroxy group (hereinafter referred to as “acid stable monomer having a hydroxy group (a2)”) or an acid stable monomer having a lactone ring (hereinafter referred to as “acid stable monomer having a lactone ring (a3)”) If a resin having a structural unit is used, the resolution and the adhesion to the substrate can be improved.

<Acid-stable monomer having a hydroxy group (a2)>
When the resist composition is used for KrF excimer laser exposure (248 nm), high energy beam exposure such as electron beam or EUV light, the acid-stable monomer (a2) having a hydroxy group has an acid having a phenolic hydroxyl group which is a hydroxystyrene. It is preferable to use a stable monomer (a2-0). When using short wavelength ArF excimer laser exposure (193 nm) or the like, an acid stable monomer having a hydroxyadamantyl group represented by formula (a2-1) should be used as the acid stable monomer having a hydroxy group (a2). Is preferred. The acid-stable monomer (a2) having a hydroxy group may be used alone or in combination of two or more.

  Examples of the monomer (a2-0) having a phenolic hydroxyl group include styrene monomers such as p- or m-hydroxystyrene represented by the formula (a2-0).

In formula (a2-0),
R ^{8 ′} represents a hydrogen atom, a halogen atom, or a C _{1 to} C ₆ alkyl group which may have a halogen atom.
R ^{9 ′} represents a halogen atom, a hydroxyl group, a C ₁ -C ₆ alkyl group, a C ₁ -C ₆ alkoxy group, a C ₂ -C ₄ acyl group, a C ₂ -C ₄ acyloxy group, an acryloyl group or a methacryloyl group.
ma represents an integer of 0 to 4. When ma is an integer of 2 or more, the plurality of R ⁹ may be the same type of group or different types of groups.

In the formula (a2-0), the alkyl group is preferably a C ₁ -C ₄ alkyl group, C ₁ -C more preferably ₂ alkyl group, a methyl group is particularly preferred.
The alkoxy group is preferably a C ₁ -C ₄ alkoxy group, more preferably C ₁ -C ₂ alkoxy group, a methoxy group is particularly preferred.

  When obtaining a copolymer resin having a structural unit derived from a monomer having such a phenolic hydroxyl group, the corresponding (meth) acrylic acid ester monomer, acetoxystyrene, and styrene are radically polymerized and then deacetylated with an acid. Can be obtained.

Examples of the monomer represented by the formula (a2-0) include the following monomers.

  Of the above monomers, 4-hydroxystyrene or 4-hydroxy-α-methylstyrene is particularly preferred.

  The content of the structural unit derived from the monomer represented by the formula (a2-0) in the resin is usually from 5 to 90 mol%, preferably from 10 to 85 mol%, more preferably in all units of the resin. Is 15 to 80 mol%.

Examples of the acid stable monomer having a hydroxyadamantyl group include a monomer represented by the formula (a2-1).
In formula (a2-1),
L ^a3 represents —O— or —O— (CH ₂ ) _k2 —CO—O—, and k2 represents an integer of 1 to 7.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom or a methyl group.
o1 represents an integer of 0 to 10.

In the formula (a2-1), L ^a3 is preferably, -O -, - O- (CH 2) f1 -CO-O- and is (wherein f1 is an integer from 1 to 4), more preferably Is —O—.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

Examples of the monoar represented by the formula (a2-1) include the following.

Among these, 3-hydroxy-1-adamantyl (meth) acrylate is preferable.

  The content of the structural unit derived from the monomer represented by the formula (a2-1) in the resin is usually 3 to 40 mol%, preferably 5 to 35 mol%, more preferably in all units of the resin. Is 5 to 30 mol%.

<Acid-stable monomer having a lactone ring (a3)>
The lactone ring possessed by the acid stable monomer (a3) may be, for example, a monocycle such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, a monocyclic lactone ring and other rings The condensed ring may be used. Among these lactone rings, a γ-butyrolactone ring and a condensed ring of a γ-butyrolactone ring and another ring are preferable.

  The acid stable monomer (a3) having a lactone ring is preferably represented by the formula (a3-1), the formula (a3-2) or the formula (a3-3). These 1 type may be used independently and may use 2 or more types together.

In formula (a3-1) to formula (a3-3),
L ^{a4 to} L ^a6 each independently represent —O— or —O— (CH ₂ ) _k3 —CO—O—, and k3 represents an integer of 1 to 7.
R ^{a18 to} R ^a20 each independently represents a hydrogen atom or a methyl group.
R ^a21 represents a C _{1 to} C ₄ aliphatic hydrocarbon group, and p1 represents an integer of 0 to 5.
R ^a22 and R ^a23 each independently represent a carboxy group, a cyano group, or a C ₁ -C ₄ aliphatic hydrocarbon group.
q1 and r1 each independently represents an integer of 0 to 3. When p1, q1 or r1 is 2 or more, a plurality of R ^a21 , R ^a22 or R ^a23 may be the same or different from each other.

Examples of L ^{a4 to} L ^a6 include those described for L ^a3 . L ^{a4 to} L ^a6 are each independently preferably —O—, —O— (CH ₂ ) _d1 —CO—O— (wherein d1 is an integer of 1 to 4), more preferably -O-. However, —O— and the like enumerated in L ^{a4 to} L ^a6 mean that they are bonded to —CO— of the formula (a3-1) to the formula (a3-3) on the left side and to the lactone ring on the right side. To do.
R ^{a18 to} R ^a20 are preferably methyl groups.
R ^a21 is preferably a methyl group.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1 to r1 are each independently preferably 0 to 2, more preferably 0 or 1.

Examples of the monomer represented by the formula (a3-1) include the following.

Examples of the monomer represented by the formula (a3-2) include the following.

Examples of the monomer represented by the formula (a3-3) include the following.

Among acid-stable monomers (a3) having a lactone ring, (meth) acrylic acid (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl, (meth) acrylic Acid tetrahydro-2-oxo-3-furyl, 2- (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yloxy) -2-oxoethyl (meth) acrylate Are preferred, and those in the form of methacrylate are more preferred.

  Content of the structural unit derived from the monomer represented by Formula (a3-1), Formula (a3-2), or Formula (a3-3) in the resin is usually 5 to 50 mol% in all units of the resin. Yes, preferably 10 to 45 mol%, more preferably 15 to 40 mol%.

<Other acid stable monomers (a4)>
Examples of the other acid stable monomer (a4) include maleic anhydride represented by formula (a4-1), itaconic anhydride represented by formula (a4-2), and formula (a4-3). And acid-stable monomers having a norbornene ring.

In formula (a4-3), R ^a25 and R ^a26 each independently represent a hydrogen atom, a C ₁ -C ₃ aliphatic hydrocarbon group ^optionally having a substituent (for example, a hydroxy group), a cyano group, A carboxy group, or a group —COOR ^a27 , or R ^a25 and R ^a26 combine with each other to form —CO—O—CO—, where R ^a27 is a C ₁ -C ₃₆ aliphatic hydrocarbon group or C ₃ —C ₃₆ represents a saturated cyclic hydrocarbon group, and —CH ₂ — in the aliphatic hydrocarbon group and saturated cyclic hydrocarbon group may be replaced by —O— or —CO—. However, those in which —COOR ^a27 is an acid labile group are excluded (that is, R ^a27 does not include those in which a tertiary carbon atom is bonded to —O—).

^Examples of the aliphatic hydrocarbon group which may have a substituent for R ^a25 and R ^a26 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a 2-hydroxyethyl group.
The carbon number of the aliphatic hydrocarbon group is preferably 1-8, more preferably 1-6, and the carbon number of the saturated cyclic hydrocarbon group is preferably 4-36, more preferably 4-12.
^Examples of R ^a27 include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group, and a 2-oxo-oxolan-4-yl group.

  Examples of the monomer represented by the formula (a4-3) include 2-norbornene, 2-hydroxy-5-norbornene, 5-norbornene-2-carboxylic acid, methyl 5-norbornene-2-carboxylate, and 5-norbornene. Examples include 2-hydroxy-1-ethyl-2-carboxylate, 5-norbornene-2-methanol, 5-norbornene-2,3-dicarboxylic acid anhydride, and the like.

  Content of the structural unit derived from the monomer represented by Formula (a4-1), Formula (a4-2), or Formula (a4-3) in the resin is usually 2 to 40 mol% in all units of the resin. Yes, preferably 3-30 mol%, more preferably 5-20 mol%.

  The resin may further contain a structural unit represented by the formula (a4-4) as an acid-stable group.

In formula (a4-4),
R ^a28 represents a hydrogen atom, a methyl group or a trifluoromethyl group.
R ^a29 represents a C _{1 to} C ₃₀ hydrocarbon group, and at least one of hydrogen atoms contained in the hydrocarbon group is substituted with a fluorine atom. —CH ₂ — contained in the hydrocarbon group may be replaced by —O—, —S— or —N (R ^a30 ) —, and the hydrogen atom contained in the hydrocarbon group is a hydroxyl group or C _1. ~C ₆ aliphatic hydrocarbon group which may be substituted.
R ^a30 represents a hydrogen atom or a C _{1 to} C ₆ aliphatic hydrocarbon group.

Specific examples of the monomer that gives the structural unit represented by the formula (a4-4) include the following monomers.

  The content of the structural unit represented by the formula (a4-4) in the resin is usually 1 to 30 mol%, preferably 2 to 20 mol%, more preferably 3 to 10 in all units of the resin. Mol%.

  Preferred resin (A) includes, in addition to the compound represented by formula (I) and the compound represented by formula (II), at least a monomer (a1) having an acid-labile group, a hydroxy group It is a copolymer obtained by polymerizing the acid-stable monomer (a2) and / or the acid-stable monomer (a3) having a lactone ring. In this preferred copolymer, the monomer (a1) having an acid labile group is more preferably at least one of a monomer (a1-1) having an adamantyl group and a monomer (a1-2) having a cyclohexyl group. A species (more preferably a monomer (a1-1) having an adamantyl group), and an acid stable monomer (a2) having a hydroxy group, preferably an acid stable monomer (a2-1) having a hydroxyadamantyl group, and a lactone The acid-stable monomer (a3) having a ring is more preferably an acid-stable monomer (a3-1) having a γ-butyrolactone ring and an acid-stable monomer (a3-2) having a condensed ring of a γ-butyrolactone ring and a norbornane ring At least one of the following. Resin (A) can be manufactured by a well-known polymerization method (for example, radical polymerization method).

  The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less). In addition, as described in the Examples, the weight average molecular weight is a value obtained by gel permeation chromatography using polystyrene as a standard product.

<Photoresist composition>
The photoresist composition of the present invention (hereinafter sometimes referred to as “resist composition”) preferably contains the resin (A), and further preferably contains an acid generator.

  It is preferable that content of resin (A) is 80 mass% or more in solid content of a composition. In the present specification, the “solid content in the composition” means the total of the composition components excluding the solvent (E). The solid content in the composition and the content of the resin (A) relative thereto can be measured by known analytical means such as liquid chromatography or gas chromatography.

<Acid generator (hereinafter sometimes referred to as "acid generator (B)")>
The acid generator (B) is classified into a nonionic type and an ionic type. Nonionic acid generators include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, DNQ 4- Sulfonate), sulfones (for example, disulfone, ketosulfone, sulfonyldiazomethane) and the like. The ionic acid generator is typically an onium salt containing an onium cation (for example, diazonium salt, phosphonium salt, sulfonium salt, iodonium salt). Examples of the onium salt anion include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

  Examples of the acid generator (B) include not only acid generators (particularly photoacid generators) used in the resist field, but also photoinitiators for photocationic polymerization, photodecolorants for dyes, and photochromic agents. Known compounds that generate an acid by radiation (light) and mixtures thereof can also be used as appropriate. For example, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, JP-A 62-153853, Acid can be obtained by radiation described in Japanese Utility Model Laid-Open No. 63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712, etc. The resulting compound can be used.

  The acid generator (B) is preferably a fluorine-containing acid generator, more preferably a sulfonate represented by the formula (B1).

In formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C _{1 to} C ₆ perfluoroalkyl group.
Y represents a C ₁ -C ₁₈ aliphatic hydrocarbon group or a C ₃ -C ₁₈ saturated cyclic hydrocarbon group, the aliphatic hydrocarbon group and a saturated cyclic hydrocarbon group may have a substituent In the aliphatic hydrocarbon group and saturated cyclic hydrocarbon group, —CH ₂ — may be replaced by —O— or —CO—.
L ^b1 represents a single bond or a divalent C _{1 to} C ₁₇ saturated hydrocarbon group, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO—.
Z ⁺ represents an organic counter ion.

  Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group. .

In the formula (B1), Q ¹ and Q ² are each independently preferably a perfluoromethyl group or a fluorine atom, more preferably a fluorine atom.
Examples of the aliphatic hydrocarbon group of Y, C ₁ ~C ₆ alkyl group is preferable.
Examples of the saturated cyclic hydrocarbon group for Y include groups represented by formulas (Y1) to (Y11). Examples of the saturated cyclic hydrocarbon group in which —CH ₂ — is replaced by —O— or —CO— in Y include, for example, a cyclic ether group (a group in which —CH ₂ — is replaced by —O—), an oxo group, and the like. A saturated cyclic hydrocarbon group having — (a group in which —CH ₂ — is replaced by —CO—), and a group in a sultone ring (two adjacent —CH ₂ — are each replaced by —O— or —SO ₂ —. Group) or a group of a lactone ring (a group in which two adjacent —CH ₂ — are replaced by —O— or —CO—, respectively), specifically, represented by formula (Y12) to formula (Y26) Group to be used.
Especially, it is preferably a group represented by any one of formulas (Y1) to (Y19), more preferably represented by formula (Y11), formula (Y14), formula (Y15) or formula (Y19). And more preferably a group represented by formula (Y11) or formula (Y14).

Examples of the substituent for Y include a halogen atom (excluding a fluorine atom), a hydroxy group, an oxo group, a C _{1 to} C ₁₂ aliphatic hydrocarbon group, a hydroxy group-containing C _{1 to} C ₁₂ aliphatic hydrocarbon group, C ₃ -C ₁₆ saturated cyclic hydrocarbon group, C ₁ -C ₁₂ alkoxy groups, C ₆ -C ₁₈ aromatic hydrocarbon group, C ₇ -C ₂₁ aralkyl group, C ₂ -C ₄ acyl group, glycidyloxy group, or - (CH ₂ ) _{j 2} —O—CO—R ^b1 group (wherein R ^b1 is a C _{1 to} C ₁₆ aliphatic hydrocarbon group, a C _{3 to} C ₁₆ saturated cyclic hydrocarbon group, or a C _{6 to} C ₁₈ aromatic group. Represents a hydrocarbon group, j2 represents an integer of 0 to 4, and the like.

Examples of the hydroxy group-containing aliphatic hydrocarbon group include a hydroxymethyl group.
The aliphatic hydrocarbon group, saturated cyclic hydrocarbon group, aromatic hydrocarbon group, aralkyl group, and the like, which are substituents for Y, may further have a substituent. Substituents here are, for example, C ₁ -C ₆ alkyl group, a halogen atom, hydroxy group, etc. oxo group.

Examples of Y having a substituent include the following.

  Y is preferably an adamantyl group optionally having a substituent (for example, an oxo group), more preferably an adamantyl group or an oxoadamantyl group.

Examples of the divalent saturated hydrocarbon group include a linear or branched alkanediyl group and a group containing a saturated cyclic hydrocarbon group.
Examples of the linear alkanediyl group include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group. , Heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1, 12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, etc. Is mentioned.
Examples of the branched alkanediyl group, a linear alkanediyl group in C ₁ -C ₄ alkyl group (e.g. methyl group, an ethyl group, a propyl group, an isopropyl group, butyl group, sec- butyl group, tert- butyl group, etc.) The one added with the side chain of.
Examples of the saturated cyclic hydrocarbon include a cycloalkanediyl group (for example, cyclohexanediyl group) and a divalent bridged cyclic hydrocarbon group (for example, adamantanediyl group).
As the saturated hydrocarbon group, these may be a combination of two or more.

The group in which —CH ₂ — of L ^b1 is replaced by —O— or —CO— is preferably any one of formula (b1-1) to formula (b1-6), more preferably formula (b1-1). To any one of formula (b1-4), more preferably represented by formula (b1-1) or formula (b1-2). Note the formula (b1-1) ~ formula (b1-6) has its left and right are described in accordance with the formula (B1), the left ^{C (Q 1) (Q 2} ) - bound to, the right side - Combine with Y. The same applies to specific examples of the following formulas (b1-1) to (b1-6).

In these equations,
L ^b2 represents a single bond or a C _{1 to} C ₁₅ saturated hydrocarbon group.
L ^b3 represents a single bond or a C _{1 to} C ₁₂ saturated hydrocarbon group,
L ^b4 represents a C _{1 to} C ₁₃ saturated hydrocarbon group. However, the upper limit of the carbon number of L ^b3 and L ^b4 is 13 or less.
L ^b5 represents a C _{1 to} C ₁₅ saturated hydrocarbon group.
L ^b6 and L ^b7 each independently represent a C _{1 to} C ₁₅ saturated hydrocarbon group. However, the upper limit of the carbon number of L ^b6 and L ^b7 is 16 or less.
L ^b8 represents a C _{1 to} C ₁₄ saturated hydrocarbon group.
L ^b9 and L ^b10 each independently represent a C _{1 to} C ₁₁ saturated hydrocarbon group. However, the upper limit of the carbon number of L ^b9 and L ^b10 is 12 or less.

Among these, a divalent group represented by the formula (b1-1) is preferable, and a divalent group represented by the formula (b1-1) in which L ^b2 is a single bond or —CH ₂ — is more preferable.

Examples of the divalent group represented by the formula (b1-1) include the following.

Examples of the divalent group represented by the formula (b1-2) include the following.

Examples of the divalent group represented by the formula (b1-3) include the following.

Examples of the divalent group represented by the formula (b1-4) include the following.

Examples of the divalent group represented by the formula (b1-5) include the following.

Examples of the divalent group represented by the formula (b1-6) include the following.

The sulfonate anion preferably has a divalent group represented by the formula (b1-1), more preferably one represented by the formula (b1-1-1) to the formula (b1-1-9). .

In formula (b1-1-1) to formula (b1-1-9), Q ¹ , Q ² and L ^b2 are the same as described above. R ^b2 and R ^b3 each independently represent a C _{1 to} C ₄ aliphatic hydrocarbon group (preferably a methyl group).

Examples of the sulfonate anion include the following.

Among these, the following sulfonate anions having a divalent group represented by the formula (b1-1) are preferable.

  Examples of the cation of the acid generator include onium cations such as sulfonium cations, iodonium cations, ammonium cations, benzothiazolium cations, and phosphonium cations. Among these, a sulfonium cation and an iodonium cation are preferable, and an arylsulfonium cation is more preferable.

Z ⁺ in formula (B1) is preferably represented by any of formula (b2-1) to formula (b2-4).
In formula (b2-1), R ^{b4 to} R ^b6 each independently represent a C _{1 to} C ₃₀ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group, or a C _{6 to} C ₁₈ aromatic hydrocarbon. represents a group, the aliphatic hydrocarbon group, hydroxy group, may be substituted by C ₁ -C ₁₂ alkoxy or C ₆ -C ₁₈ aromatic hydrocarbon group, the saturated cyclic hydrocarbon group, halogen atom may be substituted by C ₂ -C ₄ acyl group or glycidyloxy group, the aromatic hydrocarbon group, a halogen atom, hydroxy group, C ₁ -C ₃₆ aliphatic hydrocarbon group, C ₃ -C _It may be substituted with a ₃₆ saturated cyclic hydrocarbon group or a C ₁ -C ₁₂ alkoxy group.

In formula (b2-2), R ^b7 and R ^b8 each independently represent a hydroxy group, a C _{1 to} C ₁₂ aliphatic hydrocarbon group or a C _{1 to} C ₁₂ alkoxy group, and m 2 and n 2 are each independently Represents an integer of 0 to 5.

In formula (b2-3), R ^b9 and R ^b10 each independently represent a C _{1 to} C ₃₆ aliphatic hydrocarbon group or a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group. R ^b11 represents a hydrogen atom, a C _{1 to} C ₃₆ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group, or a C _{6 to} C ₁₈ aromatic hydrocarbon group.
The carbon number of the aliphatic hydrocarbon group of R ^{b9 to} R ^b11 is preferably 1 to 12, and the carbon number of the saturated cyclic hydrocarbon group is preferably 3 to 36, more preferably 4 to 12.
R ^b12 represents a C _{1 to} C ₁₂ aliphatic hydrocarbon group, a C _{3 to} C ₁₈ saturated cyclic hydrocarbon group or a C _{6 to} C ₁₈ aromatic hydrocarbon group, and the aromatic hydrocarbon group is a C ₁ to C ₁₈ C ₁₂ aliphatic hydrocarbon group, C ₁ -C ₁₂ alkoxy group, C ₃ -C ₁₈ saturated cyclic hydrocarbon group or alkylcarbonyloxy group may be substituted.
R ^b9 and R ^b10 , and R ^b11 and R ^b12 may be independently bonded to each other to form a 3- to 12-membered ring (preferably a 3- to 7-membered ring), In these rings, —CH ₂ — may be replaced by —O—, —S—, or —CO—.

In formula (b2-4), R ^{b13 to} R ^b18 each independently represents a hydroxy group, a C _{1 to} C ₁₂ aliphatic hydrocarbon group, or a C _{1 to} C ₁₂ alkoxy group. L ^b11 represents -S- or -O-. o2, p2, s2, and t2 each independently represent an integer of 0 to 5, q2 and r2 each independently represent an integer of 0 to 4, and u2 represents 0 or 1. When any of o2 to t2 is 2, any of the plurality of R ^{b13 to} R ^b18 may be the same as or different from each other.

In the formula (b2-1) to the formula (b2-4), preferred aliphatic hydrocarbon groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert- A butyl group, a pentyl group, a hexyl group, an octyl group and a 2-ethylhexyl group;
Preferred saturated cyclic hydrocarbon groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclodecyl group, a 2-alkyl-2-adamantyl group, and a 1- (1-adamantyl) -1-alkyl group. And isobornyl groups.
Preferred aromatic hydrocarbon groups include phenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-cyclohexylphenyl, 4-methoxyphenyl, biphenylyl, naphthyl Groups.
Examples of the aliphatic hydrocarbon group (aralkyl group) whose substituent is an aromatic hydrocarbon group include a benzyl group.
Examples of the ring formed by R ^b9 and R ^b10 include a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring.
^Examples of the ring formed by R ^b11 and R ^b12 include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group, and a 2-ethylhexylcarbonyloxy group.

  Among the cations (b2-1) to (b2-4), the cation (b2-1) is preferable, the cation represented by the formula (b2-1-1) is more preferable, and the triphenylsulfonium cation (formula (b2) In (1-1), v2 = w2 = x2 = 0) is more preferable.

In formula (b2-1-1), R ^{b19 to} R ^b21 each independently represent a halogen atom, a hydroxy group, a C _{1 to} C ₃₆ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group or C _{1 to} C ₁₂ alkoxy group, wherein the aliphatic hydrocarbon group may be substituted with a hydroxy group, a C _{1 to} C ₁₂ alkoxy group or a C _{6 to} C ₁₈ aromatic hydrocarbon group, and the saturated cyclic carbon group hydrogen group, a halogen atom, C ₂ -C ₄ acyl group, or a glycidyl group may be substituted.
v2 to x2 each independently represents an integer of 0 to 5 (preferably 0 or 1). When any one of v2 to x2 is 2 or more, any one of the plurality of R ^{b19 to} R ^b21 may be the same as or different from each other.

  The carbon number of the aliphatic hydrocarbon group is preferably 1 to 12, and the carbon number of the saturated cyclic hydrocarbon group is preferably 4 to 36.

In the formula (b2-1-1), R ^{b19 to} R ^b21 are preferably each independently a halogen atom (more preferably a fluorine atom), a hydroxy group, a C ₁ -C ₁₂ alkyl group, or a C _1- Represents a C ₁₂ alkoxy group, and v2 to x2 are each independently an integer of 0 to 5 (preferably 0 or 1).

Specific examples of the cation (b2-1-1) include the following.

Specific examples of the cation (b2-2) include the following.

Specific examples of the cation (b2-3) include the following.

Specific examples of the cation (b2-4) include the following.

  The acid generator (B1) is a combination of the above-described sulfonate anion and organic cation. The above-mentioned anion and cation can be arbitrarily combined, but any one of anion (b1-1-1) to anion (b1-1-9) and a cation (b2-1-1), and an anion ( A combination of any one of b1-1-3) to (b1-1-5) and a cation (b2-3) is preferable.

  Preferred acid generators (B1) are those represented by formulas (B1-1) to (B1-17), and among these, acid generators (B1-1) and (B1) containing a triphenylsulfonium cation. -2), (B1-6), (B1-11), (B1-12), (B1-13) and (B1-14) are more preferred.

  The content of the acid generator (B) is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 30 parts by mass or less (more preferably 25 parts by mass) with respect to 100 parts by mass of the resin (A). Part or less).

<Basic compound (hereinafter sometimes referred to as “basic compound (C)”)>
The resist composition of the present invention may contain a basic compound (C). The content of the basic compound (C) is preferably about 0.01 to 1% by mass based on the solid content of the resist composition.

  The basic compound (C) is preferably a basic nitrogen-containing organic compound (for example, an amine). The amine may be an aliphatic amine or an aromatic amine. As the aliphatic amine, any of primary amine, secondary amine and tertiary amine can be used. The aromatic amine may be any of an amino group bonded to an aromatic ring such as aniline and a heteroaromatic amine such as pyridine. Preferable basic compound (C) includes an aromatic amine represented by the formula (C2), particularly an aniline represented by the formula (C2-1).

In these formulas
Ar ^c1 represents an aromatic hydrocarbon group.
R ^c5 and R ^c6 each independently represent a hydrogen atom, an aliphatic hydrocarbon group, a saturated cyclic hydrocarbon group or an aromatic hydrocarbon group,
R ^c7 represents an aliphatic hydrocarbon group, an alkoxy group, a saturated cyclic hydrocarbon group or an aromatic hydrocarbon group;
The hydrogen atom of the aliphatic hydrocarbon group, saturated cyclic hydrocarbon group, aromatic hydrocarbon group and alkoxy group in R ^{c5 to} R ^c7 may be substituted with a hydroxy group, an amino group or a C _{1 to} C ₆ alkoxy group. well, wherein the amino group may be substituted by C ₁ -C ₄ alkyl group.
m3 represents an integer of 0 to 3, and when m3 is 2 or more, the plurality of R ^c7 may be the same or different from each other.

The aliphatic hydrocarbon group is preferably an alkyl group or a cycloalkyl group, and the aliphatic hydrocarbon group preferably has about 1 to 6 carbon atoms.
The carbon number of the saturated cyclic hydrocarbon group is preferably about 5 to 10.
The number of carbon atoms of the aromatic hydrocarbon group is preferably about 6 to 10.
The number of carbon atoms of the alkoxy group is preferably about 1 to 6.

  Examples of the aromatic amine (C2) include 1-naphthylamine and 2-naphthylamine. Examples of aniline (C2-1) include aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine and the like. Of these, diisopropylaniline (particularly 2,6-diisopropylaniline) is preferable.

Moreover, as a basic compound (C), the compound represented by Formula (C3)-Formula (C11) is mentioned.
In formula (C3) to formula (C11),
R ^c8 represents any of the groups described for R ^c7 in formula (C2).
R ^{c9 to} R ^c14 , R ^{c16 to} R ^c19 and R ^c22 each independently represent any of the groups described for R ^c5 and R ^c6 in formula (C2).
R ^c20 , R ^c21 , R ^{c23 to} R ^c28 each independently represents any of the groups described for R ^c7 in formula (C2-1).
R ^c15 represents an aliphatic hydrocarbon group, a saturated cyclic hydrocarbon group or an alkanoyl group.
L ^c1 and L ^c2 are each independently a divalent aliphatic hydrocarbon group, —CO—, —C (═NH) —, —C (═NR ^c3 ) —, —S—, —S—S—. or an combination thereof, R ^c3 represents a C ₁ -C ₄ alkyl group.
n3 represents an integer of 0 to 8. When n3 is 2 or more, the plurality of R ^c15 may be the same as or different from each other.
o3 to u3 each independently represents an integer of 0 to 3. When any of o3 to u3 is 2 or more, any of the plurality of R ^{c20 to} R ^c28 may be the same as or different from each other.

In Formula (C3) to Formula (C11), the carbon number of the aliphatic hydrocarbon group is preferably about 1 to 6, and the carbon number of the saturated cyclic hydrocarbon group is preferably about 3 to 6, The carbon number of the alkanoyl group is preferably about 2 to 6.
The divalent aliphatic hydrocarbon group is preferably an alkylene group, and the aliphatic hydrocarbon group preferably has about 1 to 6 carbon atoms.

  Examples of the compound (C3) include hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, Tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctyl Amine, methyl dinonyl amine, methyl didecyl amine, ethyl dibutyl amine, ethyl dipentyl amine, ethyl di Silamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine ethylenediamine, tetramethylenediamine, hexamethylene Examples include diamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and the like.

Examples of the compound (C4) include piperazine.
Examples of the compound (C5) include morpholine.
Examples of the compound (C6) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound (C7) include 2,2′-methylenebisaniline.

Examples of the compound (C8) include imidazole and 4-methylimidazole.
Examples of the compound (C9) include pyridine and 4-methylpyridine.
Examples of the compound (C10) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, and 1,2-di. (4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide, 4, 4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicolylamine and the like can be mentioned.
Examples of the compound (C11) include bipyridine.

<Solvent (sometimes referred to as "solvent (E)")
The resist composition of the present invention may contain a solvent (E). The resist composition of the present invention containing the solvent (E) is suitable for producing a thin film resist. The content of the solvent (E) is 90% by mass or more (preferably 92% by mass or more, more preferably 94% by mass or more) and 99.9% by mass or less (preferably 99% by mass or less) in the composition. The content of the solvent (E) can be measured by a known analysis means such as liquid chromatography or gas chromatography.

  Examples of the solvent (E) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and And esters such as ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; A solvent (E) may be used individually by 1 type, and may use 2 or more types together.

<Other components (hereinafter sometimes referred to as “other components (F)”)>
The resist composition of this invention may contain the other component (F) as needed. Component (F) is not particularly limited, and additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, and the like can be used.

<Method for producing resist pattern>
The method for producing a resist pattern of the present invention comprises:
(1) The process of apply | coating the resist composition of this invention mentioned above on a board | substrate,
(2) a step of removing the solvent from the composition after coating to form a composition layer;
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) The process which develops the composition layer after a heating using a image development apparatus is included.

  Application of the resist composition onto the substrate can be performed by a commonly used apparatus such as a spin coater.

The removal of the solvent is performed, for example, by evaporating the solvent using a heating device such as a hot plate or by using a decompression device to form a composition layer from which the solvent has been removed. As for the temperature in this case, about 50-200 degreeC is illustrated, for example. The pressure is exemplified by about 1 to 1.0 × 10 ⁵ Pa.

The obtained composition layer is exposed using an exposure machine. An immersion exposure machine may be used. At this time, exposure is usually performed through a mask corresponding to a required pattern. The exposure light source emits ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser, etc.) Various types of laser beam can be used, such as those that convert the wavelength of the laser beam from) to radiate a harmonic laser beam in the far ultraviolet region or the vacuum ultraviolet region.

The composition layer after the exposure is subjected to heat treatment for promoting the deprotection group reaction. As heating temperature, it is about 50-200 degreeC normally, Preferably it is about 70-150 degreeC.
The heated composition layer is usually developed using an alkali developer using a developing device.
The alkaline developer used here may be various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline).
After development, it is preferable to rinse with ultrapure water to remove water remaining on the substrate and the pattern.

<Application>
The resist composition of the present invention is suitable as a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for EB, or a resist composition for EUV exposure machines.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
In Examples and Comparative Examples, “%” and “part” representing content and use amount are based on mass unless otherwise specified.
The weight average molecular weight is a value determined by gel permeation chromatography using polystyrene as a standard product.
Column: 3 TSKgel Multipore HXL-M + guard column (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

  The structure of the compound was confirmed by NMR (GX-270 type or EX-270 type manufactured by JEOL Ltd.) and mass spectrometry (LC: Agilent 1100 type, MASS: Agilent LC / MSD type or LC / MSD TOF type).

Monomers used in Examples and Comparative Examples are shown below.

Example 1 [Synthesis of Resin A1]
Monomer A, Monomer F, Monomer B, Monomer G, Monomer H, and Monomer D are charged at a molar ratio of 31: 7: 8: 5: 5: 44, and 1.5 wt. did. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 73 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent for precipitation three times to obtain a copolymer having a weight average molecular weight of 7.2 × 10 ^{3 in} a yield of 76%. It was. This copolymer has a structural unit of the following formula, and this is designated as resin A1.

Example 2 [Synthesis of Resin A2]
Monomer E, monomer F, monomer B, monomer G, monomer H, and monomer D were charged at a molar ratio of 28: 10: 8: 5: 5: 44, and 1.5 wt. did. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent and precipitating three times to obtain a copolymer having a weight average molecular weight of 7.4 × 10 ^{3 in} a yield of 72%. It was. This copolymer has a structural unit of the following formula, and this is designated as resin A2.

Example 3 [Synthesis of Resin A3]
Monomer A, Monomer F, Monomer B, Monomer I, Monomer H, and Monomer D are charged at a molar ratio of 31: 7: 8: 5: 5: 44, and 1.5 wt. did. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent and precipitating three times to obtain a copolymer having a weight average molecular weight of 7.0 × 10 ^{3 in} a yield of 70%. It was. This copolymer has a structural unit of the following formula, and this is designated as resin A3.

[Synthesis of Resin X1]
Monomer A, monomer B, and monomer D were charged at a molar ratio of 50:25:25, and 1.5 weight times dioxane of the total monomer amount was added to prepare a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 77 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a mixed solvent of a large amount of methanol and water three times to obtain a copolymer having a weight average molecular weight of 8.1 × 10 ^{3 in} a yield of 55%. . This copolymer has a structural unit of the following formula, and this is designated as resin X1.

Examples and Comparative Examples The following components were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist solution.

<Acid generator>
B1a:
B2:
<Basic compound: Quencher>
C1: 2,6-Diisopropylaniline <Solvent>
Propylene glycol monomethyl ether acetate 265 parts 2-heptanone 20.0 parts Propylene glycol monomethyl ether 20.0 parts γ-butyrolactone 3.5 parts

An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 78 nm. An organic antireflection film was formed. Next, the above resist composition was spin-coated on the organic antireflection film so that the film thickness after drying was 85 nm.
After applying the resist composition, the obtained silicon wafer was pre-baked (PB) for 60 seconds on a direct hot plate at the temperature described in the “PB” column of Table 1. Using the ArF excimer stepper for immersion exposure [XT: 1900Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light] on the wafer on which the resist composition film is formed in this manner, the exposure amount is stepwise. The line and space pattern was subjected to immersion exposure.
After the exposure, post exposure bake (PEB) is performed on the hot plate at a temperature described in the “PEB” column of Table 1 for 60 seconds, and further with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed.

  In each resist film, the exposure amount at which the 50 nm line and space pattern becomes an exposure amount of 1: 1 was defined as the effective sensitivity.

  Resolution evaluation: In terms of effective sensitivity, the resist pattern was observed with a scanning electron microscope.

  Focus margin evaluation (DOF: Depth of Focus): When the focus is moved in the effective sensitivity, the range (47.5 to 52.5 nm) in which the line width is 50 nm ± 5% is used as the line width index. Those having a diameter of 0.15 μm or more were rated as “◯”, and those having a diameter of less than 0.15 μm were marked as “X”.

Exposure margin evaluation (EL; Exposure Latitude): The exposure amount range of effective sensitivity ± 10% is plotted on the horizontal axis, and the line width of a 50 nm line and space pattern at the exposure amount is plotted on the vertical axis. The absolute value of the slope of the straight line, 1.3 nm / (mJ / cm ²⁾ for the following ○, and as × in excess of ^{1.3nm / (mJ / cm 2)} .
These results are shown in Table 2.

  According to the resin of the present invention, a pattern having excellent resolution, focus margin and exposure margin can be formed using a photoresist composition containing the resin.

Claims (14)

A resin having a structural unit derived from a compound represented by formula (I) and a structural unit derived from a compound represented by formula (II).
[In the formula (I),
R ¹ represents a hydrogen atom, a halogen atom or a C ₁ -C ₆ alkyl group which may have a halogen atom.
X ¹ represents a C _{2 to} C ₃₆ heterocyclic group, and a hydrogen atom contained in the heterocyclic group is a halogen atom, a hydroxyl group, a C _{1 to} C ₂₄ hydrocarbon group, a C _{1 to} C ₁₂ alkoxy group, or C _2. -C ₄ acyl group or _C 2 -C ₄ may be substituted with an acyloxy group, -CH contained in the heterocyclic group ₂ - may be replaced by -CO- or -O-. ]
[In the formula (II),
R ³¹ represents a C ₁ -C ₆ alkyl group which may have a hydrogen atom, a halogen atom or a halogen atom.
Z ¹ represents a divalent C _{1 to} C ₁₇ saturated hydrocarbon group, and —CH ₂ — contained in the saturated hydrocarbon group is —CO—, —O—, —S—, or —N (R ³² )-May be replaced.
R ³² represents a hydrogen atom or a C ₁ -C ₆ alkyl group.
T represents a heterocyclic group containing —SO ₂ — in the skeleton, and the hydrogen atom contained in the heterocyclic group is a halogen atom, a hydroxyl group, a C ₁ -C ₁₂ alkyl group, a C ₁ -C ₁₂ alkoxy group, C ₆ -C ₁₂ aryl _group, C 7 _{-C 13} aralkyl group may be substituted with a glycidyl group or a _C 2 -C ₄ acyl group, -CH contained in the heterocyclic group ₂ -, -CO- , —O—, —S—, —SO ₂ — or —N (R ³³ ) — may be substituted.
R ³³ represents a hydrogen atom or a C ₁ -C ₆ alkyl group. ] The resin according to claim 1, wherein the compound represented by the formula (I) is a compound represented by the formula (III).
[In the formula (III),
R ² represents a C _{1 to} C ₆ alkyl group which may have a hydrogen atom, a halogen atom or a halogen atom.
R ^{3 to} R ⁸ each independently represents a hydrogen atom or a C _{1 to} C ₂₄ hydrocarbon group, or at least two selected from R ^{3 to} R ⁸ are bonded to each other to form a ring of C _{3 to} C ₃₀ . It is formed and hydrogen atoms contained in the hydrocarbon group and the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _group, C 2 -C ₄ acyl group or a _C 2 ~ It may be substituted with a C ₄ acyloxy group, and —CH ₂ — contained in the hydrocarbon group and the ring may be replaced with —CO— or —O—.
t1 represents an integer of 0 to 3. ] The resin according to claim 1 or 2, wherein the compound represented by the formula (I) is a compound represented by the formula (IV).
[In the formula (IV),
R ⁹ represents a hydrogen atom, a halogen atom or a C ₁ -C ₆ alkyl group which may have a halogen atom.
R ^{10 to} R ¹⁹ each independently represents a hydrogen atom or a C _{1 to} C ₁₂ hydrocarbon group, or at least two selected from R ^{10 to} R ¹⁹ are bonded to each other to form a ring of C _{3 to} C ₂₄ . It is formed and hydrogen atoms contained in the hydrocarbon group and the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _group, C 2 -C ₄ acyl group or a _C 2 ~ It may be substituted with a C ₄ acyloxy group, and —CH ₂ — contained in the hydrocarbon group and the ring may be replaced with —CO— or —O—.
t2 and t3 each independently represents an integer of 0 to 3. ] The resin according to any one of claims 1 to 3, wherein the compound represented by the formula (I) is a compound represented by the formula (V).
[In the formula (V),
R ²⁰ represents a C ₁ -C ₆ alkyl group which may have a hydrogen atom, a halogen atom or a halogen atom.
R ²¹ represents a halogen atom, a hydroxyl group, a C _{1 to} C ₁₂ alkyl group, a C _{1 to} C ₁₂ alkoxy group, a C _{2 to} C ₄ acyl group, or a C _{2 to} C ₄ acyloxy group.
t4 represents an integer of 0 to 8. ]   The resin according to any one of claims 1 to 4, wherein T is a group having a norbornane skeleton. T is group represented by a formula (T3), Resin in any one of Claims 1-5.
[In the formula (T3),
Hydrogen atoms contained in the ring, a halogen atom, a hydroxyl _group, C 1 _{-C 12} alkyl _group, C 1 _{-C 12} alkoxy _groups, C 6 _{-C 12} aryl _group, C 7 _{-C 13} aralkyl group, glycidoxy group or _{C 2} It may be substituted with -C ₄ acyl group, _-CH 2 contained in the ring - is, -CO -, - O -, - S -, - SO 2 - or -N ^{(R 33)} - in has been replaced May be.
R ³³ represents a hydrogen atom or a C ₁ -C ₆ alkyl group.
* Represents a bond. ]   The resin according to any one of claims 1 to 6, further comprising a structural unit derived from an acid-stable monomer having a hydroxy group or an acid-stable monomer having a lactone ring. Furthermore, the resin according to any one of claims 1 to 7 , which has an acid-labile group, is insoluble or hardly soluble in an aqueous alkaline solution, and can be dissolved in an aqueous alkaline solution by acting with an acid. A photoresist composition comprising a resin and a photoacid generator according to any one of claims 1-8. The photoresist composition according to claim 9 , wherein the acid generator is an acid generator represented by the formula (B1).
[In Formula (B1), Q ¹ and Q ² each independently represent a fluorine atom or a C ₁ -C ₆ perfluoroalkyl group.
L ^b1 represents a single bond or a divalent C _{1 to} C ₁₇ saturated hydrocarbon group, and —CH ₂ — of the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Y represents a C _{1 to} C ₁₈ aliphatic hydrocarbon group which may have a substituent or a C _{3 to} C ₁₈ saturated cyclic hydrocarbon group which may have a substituent, and the aliphatic hydrocarbon —CH ₂ — contained in the group and the saturated cyclic hydrocarbon group may be replaced by —O—, —SO ₂ — or —CO—.
Z ⁺ represents an organic cation. ] The photoresist composition according to claim 10 , wherein L ^b1 is * —CO—O— (* represents a bond with —C (Q ¹ ) (Q ² ) —). The photoresist composition according to claim 10 or 11 , wherein Z ⁺ is an arylsulfonium cation. The photoresist composition according to claim 9 , comprising a basic compound. (1) The process of apply | coating the photoresist composition in any one of Claims 9-13 on a board | substrate,
(2) a step of removing the solvent from the composition after coating to form a composition layer;
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) A method for producing a resist pattern, comprising a step of developing the heated composition layer using a developing device.