JP5722558B2 - Resist composition - Google Patents

Description

  The present invention relates to a resist composition.

In microfabrication of a semiconductor, it is desirable to form a pattern with high resolution.
In Patent Document 1, 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate and α-methacryloyloxy-γ-butyrolactone are charged at a molar ratio of 50:25:25 and polymerized. A chemical amplification type comprising: a resin comprising: an acid generator comprising triphenylsulfonium 1-((3-hydroxyadamantyl) methoxycarbonyl) difluoromethanesulfonate; a quencher comprising 2,6-diisopropylaniline; and a solvent. A photoresist composition is described.

JP 2006-257078 A

  In the conventional resist composition, the shape of the pattern obtained, the focus margin (DOF), and the mask error factor (MEF) are not always satisfactory.

The present invention includes the following inventions.
[1] A resist composition comprising a salt represented by the formula (AA) and a resin having a repeating unit derived from the compound represented by the formula (II).
[In the formula (AA)
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —O— or It may be replaced by -CO-.
T represents an alicyclic hydrocarbon group having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group includes a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, and 1 to 1 carbon atoms. The alicyclic hydrocarbon group may be substituted with an alkoxy group having 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, or an acyl group having 2 to 4 carbon atoms. —CH ₂ — contained in is substituted with at least one —SO ₂ —, and is further substituted with —CO—, —O—, —S—, —SO ₂ — or —N (R ^c ) —. May be. R ^c represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms.
Z ⁺ represents an organic cation. ]
[In the formula (II),
R ³ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
X represents —CH ₂ —, —O— or —S—. ]

[2] The resist composition according to [1], wherein T is a group represented by the formula (T1).
[In the formula (T1),
The hydrogen atom contained in the ring is a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or glycidyl. It may be substituted with an oxy group or an acyl group having 2 to 4 carbon atoms, and —CH ₂ — contained in the ring is replaced with at least one —SO ₂ —, and further —CO—, —O— , —S—, —SO ₂ — or —N (R ^c ) — may be substituted. R ^c represents the same meaning as described above.
* Represents a bond to ^{X 1.}
T ¹ represents an oxygen atom or a methylene group. ]

[3] The resist composition according to [1] or [2], wherein T is a group represented by the formula (T2).
[In the formula (T2),
The hydrogen atom contained in the ring includes a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, and glycidoxy -CH _2- which may be substituted with a group or an acyl group having 2 to 4 carbon atoms and is included in the ring is -CO-, -O-, -S-, -SO ₂ -or -N (R ^c )-May be replaced. R ^c and * represent the same meaning as described above. ]

[4] ^{X 1} is a group represented by the formula (x-1) [1] The resist composition according to any one of - [3].
[In the formula (x-1),
X ² represents a divalent saturated hydrocarbon group having 1 to 16 carbon atoms.
X ³ represents a single bond or a divalent saturated hydrocarbon group having 1 to 16 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group is —O—, —CO— or —N (R ^c The hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxyl group, a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms. Good. R ^c represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms.
m represents an integer of 0-2. ]

[5] The resist according to any one of [1] to [4], wherein X ¹ is * —CO—O— (* represents a bond with —C (Q ¹ ) (Q ² ) —). Composition.

[6] The resist composition according to any one of [1] to [5], wherein Z ⁺ is an arylsulfonium cation.

  [7] The resin further has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution, and is a resin that can be dissolved in an alkaline aqueous solution by the action of an acid [1] to [6]. The resist composition according to any one of the above.

  [8] The resist composition according to any one of [1] to [7], further containing a basic compound.

  According to the resist composition of the present invention, a pattern having an excellent shape, DOF and MEF can be formed.

In this specification, unless otherwise specified, specific chemical substituents described later can be applied to any chemical structural formula having the same substituents while appropriately selecting the number of carbon atoms. Those which can take any of linear, branched or cyclic are included unless otherwise specified, and in the same group, linear, branched and / or cyclic partial structures are mixed. It may be. When stereoisomers exist, all of those 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.

  The resist composition of the present invention contains a salt represented by the formula (AA) and a resin having a repeating unit derived from the compound represented by the formula (II).

<Salt represented by formula (AA) (hereinafter sometimes referred to as salt (AA))>
[In the formula (AA)
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —O— or It may be replaced by -CO-.
T represents an alicyclic hydrocarbon group having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group includes a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, and 1 to 1 carbon atoms. The alicyclic hydrocarbon group may be substituted with an alkoxy group having 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, or an acyl group having 2 to 4 carbon atoms. —CH ₂ — contained in is substituted with at least one —SO ₂ —, and is further substituted with —CO—, —O—, —S—, —SO ₂ — or —N (R ^c ) —. May be. R ^c represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms.
Z ⁺ represents an organic cation. ]

  Examples of perfluoroalkyl groups include perfluoromethyl group, perfluoroethyl group, perfluoro-n-propyl group, perfluoroisopropyl group, perfluoro-n-butyl group, perfluoro-sec-butyl group, perfluoro-tert-butyl group, perfluoro-n- A pentyl group, a perfluoro-n-hexyl group, etc. are mentioned. Of these, a perfluoromethyl group is preferable.

Examples of the divalent saturated hydrocarbon group include linear, branched or cyclic saturated hydrocarbons. Specific examples include a divalent group including an alkylene group and a cycloalkylene group.
Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, an isopropylene group, a sec-butylene group, and a tert-butylene group.
Examples of the divalent group containing a cycloalkylene group include groups represented by the formula (X ¹ -A) to the formula (X ¹ -C).
[In the formulas (X ¹ -A) to (X ¹ -C), X ^1A and X ^1B each independently represent an optionally substituted alkylene group having 1 to 6 carbon atoms, —CH ₂ — contained in the alkylene group may be replaced by —O— or —CO—. However, the number of carbon atoms of the group represented by the formula ^(X 1 -A) ~ Formula ^(X 1 -C) is 1 to 17. ]

  Examples of the alicyclic hydrocarbon group include cycloalkyl such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, adamantyl group, and isobornyl group. Groups.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
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 aryl group include a phenyl group, a naphthyl group, an anthranyl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group; a tolyl group, a xylyl group, a cumenyl group, a mesityl group, and a biphenyl group. , An anthryl group, a phenanthryl group, a 2,6-diethylphenyl group, an aromatic hydrocarbon group such as 2-methyl-6-ethylphenyl.
Examples of the aralkyl group include benzyl, phenethyl, phenylpropyl, trityl, naphthylmethyl group, naphthylethyl group, and the like.
Examples of the acyl group include acetyl, propionyl, butyryl and the like.
Examples of the aliphatic hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, heptyl. And alkyl groups such as 2-ethylhexyl group, octyl group, nonyl group, decyl group, undecyl group and dodecyl group.

In the anion of the salt represented by the formula (AA), Q ¹ and Q ² are preferably each independently a fluorine atom or —CF ₃ , and more preferably both are fluorine atoms.

Examples of the substituent in X ¹ include a halogen atom, a hydroxyl group, a carboxyl group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and an aromatic carbon atom having 6 to 20 carbon atoms. Examples thereof include a hydrogen group, an aralkyl group having 7 to 21 carbon atoms, a glycidyloxy group, and an acyl group having 2 to 4 carbon atoms.

Examples of the group in which —CH ₂ — contained in the saturated hydrocarbon group for X ¹ is replaced by —O— or —CO— include, for example, —X ¹¹ —O—, —X ¹¹ —CO—O—, —X ^{11 -O-CO -, - X} 11 -O-X 11 -, - O-X 11 -, - CO-O-X 11 - , and the like.
Here, X ^11, independently of one another, represent a saturated hydrocarbon group having a single bond or a substituent 1 to 15 carbon atoms which may have a. However, in the group in which the methylene group contained in the saturated hydrocarbon group is substituted, the number of atoms constituting the main chain of each of the above groups is 1 to 17.

X ¹ is preferably a group represented by the formula (X ¹ -1).
[In the formula (X ¹ -1),
X ^a1 represents a C1-C15 saturated hydrocarbon group which may have a single bond or a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —O— or —CO—. It may be replaced with. * Represents a bond with —C (Q ¹ ) (Q ² ) —. ]

X ¹ is preferably a group represented by the formula (x-1).
[In the formula (x-1),
X ² represents a saturated hydrocarbon group having 1 to 16 carbon atoms.
X ³ represents a single bond or a saturated hydrocarbon group having 1 to 16 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group is —O—, —CO—, or —N (R ^c ) —. The hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxyl group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. R ^c represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms.
m represents an integer of 0-2. ]

In the group represented by the formula (x-1), X ² and X ³ are preferably alkylene groups.
M is preferably 0.

Specific examples of X ¹ include the following groups.

In particular, examples of the group represented by the formula (x-1) include the following.
Among these, X ¹ is preferably * —CO—O— (* represents a bond with —C (Q ¹ ) (Q ² ) —).

T is suitably an alicyclic hydrocarbon group having 4 to 36 carbon atoms which may have a substituent.
In particular, T is suitably a group represented by the formula (T0), and among them, a group represented by the formula (T0a) is preferable.
Further, T is preferably a group represented by the formula (T1), and more preferably a group represented by the formula (T1a).
Further, T is more preferably a group represented by the formula (T2), and among them, a group represented by the formula (T2a) is even more preferable.
[Where:
The hydrogen atom contained in the ring is a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or glycidyl. It may be substituted with an oxy group or an acyl group having 2 to 4 carbon atoms.
The methylene group contained in the ring is substituted with at least one —SO ₂ — as in T2 and T2a, and is further substituted with a carbonyl group, an oxygen atom, a sulfur atom, —SO ₂ — or —N (R ^c ). It may be substituted with-.
R ^c represents the same meaning as described above.
* Represents a bond with ^{X 1.}
T ¹ represents an oxygen atom or a methylene group. ]

Examples of T include the following.

Examples of the anion of the salt represented by the formula (AA) include the following.

Examples of Z ^{+ in the} salt represented by the formula (AA) include cations such as the formula (IXz), the formula (IXb), the formula (IXc), and the formula (IXd).

[In formula (IXz), P ^a , P ^b and P ^c are each independently a linear or branched alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, or Represents an aromatic hydrocarbon group having 6 to 20 carbon atoms.
When any one of P ^a , P ^b and P ^c is an alkyl group, the alkyl group is a hydroxyl group, a linear or branched alkoxy group having 1 to 12 carbon atoms, or a cyclic carbonization having 3 to 12 carbon atoms. May be substituted with a hydrogen group,
When any of P ^a , P ^b and P ^c is an alicyclic hydrocarbon group or an aromatic hydrocarbon, a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched ^C 1-12 carbon atom Represents an alkyl group, a linear or branched alkoxy group having 1 to 12 carbon atoms or an alicyclic hydrocarbon having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom, Hydroxyl group, linear or branched alkyl group having 1 to 12 carbon atoms, linear or branched alkoxy group having 1 to 12 carbon atoms, aryl group having 6 to 12 carbon atoms, aralkyl having 7 to 12 carbon atoms Group, a glycidyloxy group, or an acyl group having 2 to 4 carbon atoms.
In formula (IXb), P ⁴ and P ⁵ each independently represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

In formula (IXc), P ⁶ and P ⁷ each independently represent a linear or branched alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms, or P ⁶ and P ^7. And may form a ring having 3 to 12 carbon atoms.
P ⁸ represents a hydrogen atom, and P ⁹ is a linear or branched alkyl group having 1 to 12 carbon atoms and a C 6 to 20 carbon atom that may be substituted with a cycloalkyl group having 3 to 12 carbon atoms. Or P ⁸ and P ⁹ may be combined to form a ring having 3 to 12 carbon atoms.

In formula (IXd), P ^{10 to} P ²¹ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
E represents a sulfur atom or an oxygen atom.
m represents 0 or 1. ]

The alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, alkoxy group, cycloalkyl group and the like are the same as described above.
Examples of the cyclic hydrocarbon group include an alicyclic hydrocarbon group and an aromatic hydrocarbon group. Examples of the ring include a 3-membered ring to a 12-membered ring (preferably a 3-membered ring to a 7-membered ring). These rings —CH ₂ — may be replaced by —O—, —S— or —CO—. Specifically, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, a 1,4-oxathian-4-ium ring, an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, Examples thereof include an oxoadamantane ring.

Among the cations represented by the formula (IXz), for example, a cation represented by the formula (IXa) is preferable.
[In the formula (IXa)
P ^{1 to} P ³ are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched alkoxy group having 1 to 12 carbon atoms. Alternatively, it represents an alicyclic hydrocarbon having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, It is substituted with a linear or branched alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, or an acyl group having 2 to 4 carbon atoms. May be. ]

  In particular, those containing an adamantyl skeleton and an isobornyl skeleton are suitable as the alicyclic hydrocarbon group, preferably a 2-alkyl-2-adamantyl group, a 1- (1-adamantyl) -1-alkyl group, an isobornyl group, and the like. Is mentioned.

Examples of the cation represented by the formula (IXa) include the followings.

  Among the cations represented by the formula (IXa), the cation represented by the formula (IXe) is preferably used because of its easy production.

[In the formula (IXe)
P ²² , P ²³ and P ²⁴ are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched carbon number 1 to 12. Represents an alkoxy group. ]

Examples of the cation represented by the formula (IXb) include the followings.

Examples of the cation represented by the formula (IXc) include the followings.

Examples of the cation represented by the formula (IXd) include the followings.

Among these, Z ⁺ is preferably an arylsulfonium cation.
The anions and cations described above can be arbitrarily combined.

For example, the following are mentioned as a salt represented by a formula (AA).

The salt (AA) can be produced, for example, by the following method.
For example, the salt represented by the formula (IA) where X ¹ is —CO—O— is obtained by reacting the salt represented by the formula (IA-a) and the compound represented by the formula (IA-b) with an acid catalyst. Then, it can be obtained by reacting in a solvent.
Examples of the acid catalyst include sulfuric acid.
Examples of the solvent include monochlorobenzene.
The salt represented by the formula (IA-b) can be produced by the method described in JP-A-2008-13551.

Examples of the compound represented by the formula (IA-b) include compounds represented by the following.

The salt represented by the formula (AA) can be used as an acid generator of the resist composition, and may be used alone or in combination of two or more.
Further, the resist composition further includes, as an acid generator, a known salt other than the salt represented by the formula (AA), a salt composed of a cation and a known anion contained in the salt represented by the formula (AA), and An anion contained in the salt represented by the formula (AA) and a salt composed of a known cation may be included.

  The content of the acid generator 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 or less) with respect to 100 parts by mass of the resin.

<Resin having a repeating unit derived from the compound represented by formula (II)>
[In the formula (II),
R ³ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
X represents —CH ₂ —, —O— or —S—. ]
Examples of the alkyl group that 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, and a perfluoropentyl group. And perfluorohexyl group.

In the compound represented by formula (II), R ³ is preferably a hydrogen atom or a methyl group.
Examples of the compound represented by the formula (II) include the following compounds.

  In addition to the repeating unit derived from the monomer represented by the formula (II), the resin contained in the resist composition of the present invention further has an acid-labile group and is insoluble or hardly soluble in an aqueous alkali solution. It is preferably a resin that can be dissolved in an alkaline aqueous solution by the action of an acid.

  In the resist composition of the present invention, the salt represented by the formula (AA) which is an acid generator generates an acid upon exposure and acts catalytically on a group in the resin which is unstable to the acid. To make the resin soluble in an alkaline aqueous solution. Such a resist composition is suitable as a chemically amplified positive resist composition.

  That is, a resin having an “acid-labile group” means insoluble or hardly soluble in an aqueous alkali solution before contact with an acid, but becomes soluble in an aqueous alkali solution after contact with an acid. . In such a resin, part or all of the hydrophilic group in the molecule is protected by a protecting group that can be removed by contact with an acid. When the resin comes into contact with an acid, the protecting group is removed. Upon release, the resin is converted to a resin that is soluble in an aqueous alkaline solution. Hereinafter, the hydrophilic group protected by the protecting group is referred to as “acid-labile group”. Examples of the hydrophilic group include a hydroxy group or a carboxy group, and a carboxy group is more preferable.

When the hydrophilic group is a carboxy group, the acid labile group is such that the hydrogen atom of the carboxy group is replaced with an organic residue, and the atom of the organic residue bonded to the oxy group is a tertiary carbon atom. Groups. Among such acid labile groups, preferred acid labile groups are, for example, those represented by the following formula (1) (hereinafter sometimes referred to as “acid labile group (1)”) It is said.)
In formula (1),
R ^a1 , R ^a2 and R ^a3 each independently represent an aliphatic hydrocarbon group having 1 to 8 carbon atoms or an alicyclic group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 are bonded to each other. Then, a ring having 3 to 20 carbon atoms is formed with the carbon atom to which they are bonded. When the ring formed by combining R ^a1 and R ^a2 , the aliphatic hydrocarbon group or the alicyclic group has a methylene group, —CH ₂ — contained therein is —O—, —S— or It may be replaced by -CO-. * Represents a bond.

Examples of the aliphatic hydrocarbon group represented by R ^{a1 to} R ^a3 include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
The alicyclic group of R ^{a1 to} R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, a methylnorbornyl group, and groups shown below.
This alicyclic group preferably has 1 to 16 carbon atoms.

When R ^a1 and R ^a2 are bonded to each other to form a ring, examples of the —C (R ^a1 ) (R ^a2 ) (R ^a3 ) group include the following groups.
In the formula (1), the number of carbon atoms in such a ring is preferably 3-12.

  Examples of the group having a carboxylic acid ester include a group having a (meth) acrylic acid ester, a norbornene carboxylic acid ester, a tricyclodecene carboxylic acid ester, and a tetracyclodecene carboxylic acid ester.

Specific examples of the acid labile group (1) are:
1,1-dialkylalkoxycarbonyl group (in formula (1), R ^{a1 to} R ^a3 are all alkyl groups, and one of these alkyl groups is preferably a tert-butoxycarbonyl group),
2-alkyl-2-adamantyloxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are bonded to each other to form an adamantyl ring together with the carbon atom to which they are bonded, 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).

In the case where the hydrophilic group is a hydroxy group, examples of the acid labile group include those in which the hydrogen atom of the hydroxy group is replaced with an organic residue to become a group containing an acetal structure. Among such acid labile groups, preferred acid labile groups are, for example, those represented by the following formula (2) (hereinafter referred to as “acid labile group (2)” in some cases. ).

In formula (2),
R ^b1 and R ^b2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^b3 represents a hydrocarbon group having 1 to 20 carbon atoms, or R ^b2 and R ^b3 Are bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom and the oxygen atom to which they are bonded. When R ^b2 and R ^b3 have a ring formed by bonding to each other or the hydrocarbon group methylene group, —CH ₂ — contained therein may be replaced by —O—, —S— or —CO—. Good. * Represents a bond.

Examples of the hydrocarbon group include an aliphatic hydrocarbon group, an alicyclic group, and an aromatic hydrocarbon group. Here, the aliphatic hydrocarbon group and the alicyclic group are the same as those described as the groups R ^{a1 to} R ^a3 . Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, anthranyl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, Examples thereof include aryl groups such as biphenyl group, anthryl group, phenanthryl group, 2,6-diethylphenyl group, and 2-methyl-6-ethylphenyl.
At least one of R ^{b1 to} R ^b2 is preferably a hydrogen atom.

Examples of the acid labile group (2) include the following groups.

The resin can be produced by addition polymerization of a monomer having an acid labile group and an olefinic double bond.
Such monomers include bulky groups such as alicyclic structures such as 2-alkyl-2-adamantyl groups and 1- (1-adamantyl) -1-alkylalkyl groups as acid labile groups. Monomers are preferred because the resolution of the resulting resist tends to be excellent.

  Specific examples of the monomer containing a bulky group include 2-alkyl-2-adamantyl (meth) acrylate, 1- (1-adamantyl) -1-alkylalkyl (meth) acrylate, and 5-norbornene-2. -2-alkyl-2-adamantyl carboxylate, 1- (1-adamantyl) -1-alkylalkyl 5-norbornene-2-carboxylate, 2-alkyl-2-adamantyl α-chloroacrylate, α-chloroacrylic acid 1- (1-adamantyl) -1-alkylalkyl and the like.

  In particular, when 2-alkyl-2-adamantyl (meth) acrylate or 2-alkyl-2-adamantyl α-chloroacrylate is used as a monomer, it is preferable because the resolution of the resulting resist tends to be excellent.

  Specifically, as 2-alkyl-2-adamantyl (meth) acrylate, for example, 2-methyl-2-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-acrylate Examples include adamantyl, 2-ethyl-2-adamantyl methacrylate, 2-n-butyl-2-adamantyl acrylate, and the like. Examples of the α-chloro-2-alkyl-2-adamantyl α-chloroacrylate include 2-methyl-2-adamantyl α-chloroacrylate, 2-ethyl-2-adamantyl α-chloroacrylate, and the like.

  Among these, when 2-ethyl-2-adamantyl (meth) acrylate or 2-isopropyl-2-adamantyl (meth) acrylate is used, the resulting resist tends to have excellent sensitivity and heat resistance. preferable.

  (Meth) acrylic acid 2-alkyl-2-adamantyl can be usually produced by a reaction of 2-alkyl-2-adamantanol or a metal salt thereof with acrylic acid halide or methacrylic acid halide.

The resin may contain repeating units derived from acid stable monomers. Here, the structure derived from an acid-stable monomer means a structure that is not cleaved by an acid generator.
Specifically, a repeating unit derived from a monomer having a free carboxylic acid group such as acrylic acid or methacrylic acid, a repeating unit derived from an aliphatic unsaturated dicarboxylic anhydride such as maleic anhydride or itaconic anhydride , A repeating unit derived from 2-norbornene, a repeating unit derived from (meth) acrylonitrile, an alkyl ester or 1-adamantyl ester in which the carbon atom adjacent to the oxygen atom is a secondary or tertiary carbon atom (meth) Derived from a repeating unit derived from an acrylate ester, a repeating unit derived from a styrene monomer such as p- or m-hydroxystyrene, and a (meth) acryloyloxy-γ-butyrolactone in which the lactone ring may be substituted with an alkyl group And the like. In the 1-adamantyl ester, the carbon atom adjacent to the oxygen atom is a quaternary carbon atom. However, the 1-adamantyl ester is an acid-stable group, and a hydroxyl group or the like may be bonded to the 1-adamantyl ester.

  Specific examples of acid-stable monomers include 3-hydroxy-1-adamantyl (meth) acrylate, 3,5-dihydroxy-1-adamantyl (meth) acrylate, α- (meth) acryloyloxy-γ-butyrolactone, β- (meth) acryloyloxy-γ-butyrolactone, a monomer that gives a repeating unit represented by the formula (a), a monomer that gives a repeating unit represented by the formula (b), hydroxystyrene, norbornene, etc. Examples thereof include an alicyclic compound having a bond, an aliphatic unsaturated dicarboxylic acid anhydride such as maleic anhydride, and itaconic anhydride.

  Among them, in particular, a repeating unit derived from a styrenic monomer such as p- or m-hydroxystyrene, a repeating unit derived from 3-hydroxy-1-adamantyl (meth) acrylate, (meth) acrylic acid 3,5- A resist obtained from a resin containing any one of a repeating unit derived from dihydroxy-1-adamantyl, a repeating unit represented by the formula (a), and a repeating unit represented by the formula (b) has the following characteristics: This is preferable because the resolution tends to be improved.

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group; R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group, a trifluoromethyl group, or a halogen atom; And j represents an integer of 1 to 3. When i is 2 or 3, R ³ may be a different group, and when j is 2 or 3, R ⁴ may be a different group. Good.)

  Monomers such as (meth) acrylic acid 3-hydroxy-1-adamantyl and (meth) acrylic acid 3,5-dihydroxy-1-adamantyl are commercially available. For example, it can also be produced by reacting the corresponding hydroxyadamantane with (meth) acrylic acid or its halide.

  In addition, a monomer such as (meth) acryloyloxy-γ-butyrolactone is obtained by reacting α- or β-bromo-γ-butyrolactone, in which the lactone ring may be substituted with an alkyl group, with acrylic acid or methacrylic acid, or lactone It can be produced by reacting an α- or β-hydroxy-γ-butyrolactone whose ring may be substituted with an alkyl group with an acrylic acid halide or a methacrylic acid halide.

  Examples of the monomer that gives the repeating unit represented by the formulas (a) and (b) include (meth) acrylic acid esters of alicyclic lactones having the following hydroxyl groups, and mixtures thereof. These esters can be produced, for example, by a reaction between a corresponding alicyclic lactone having a hydroxyl group and (meth) acrylic acid (see, for example, JP-A No. 2000-26446).

  Here, as (meth) acryloyloxy-γ-butyrolactone, for example, α-acryloyloxy-γ-butyrolactone, α-methacryloyloxy-γ-butyrolactone, α-acryloyloxy-β, β-dimethyl-γ-butyrolactone, α- Methacryloyloxy-β, β-dimethyl-γ-butyrolactone, α-acryloyloxy-α-methyl-γ-butyrolactone, α-methacryloyloxy-α-methyl-γ-butyrolactone, β-acryloyloxy-γ-butyrolactone, β- Examples include methacryloyloxy-γ-butyrolactone, β-methacryloyloxy-α-methyl-γ-butyrolactone, and the like.

In the case of KrF excimer laser exposure and EUV exposure, sufficient transmittance can be obtained even when a repeating unit derived from a styrene monomer such as p- or m-hydroxystyrene is used as the resin repeating unit. Such a copolymer resin can be obtained by radically polymerizing the corresponding (meth) acrylic acid ester monomer, acetoxystyrene, and styrene and then deacetylating with an acid.
As a monomer which gives the repeating unit derived from a styrene-type monomer, the following compounds are mentioned, for example.

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

  Moreover, since the resin containing a repeating unit derived from 2-norbornene has an alicyclic skeleton directly in its main chain, it has a strong structure and exhibits excellent dry etching resistance. The repeating unit derived from 2-norbornene can be introduced into the main chain by radical polymerization using, in addition to the corresponding 2-norbornene, an aliphatic unsaturated dicarboxylic acid anhydride such as maleic anhydride or itaconic anhydride. Therefore, the one formed by opening the double bond of the norbornene structure can be represented by the formula (c), and the one formed by opening the double bond of maleic anhydride and itaconic anhydride is respectively It can represent with Formula (d) and Formula (e).

Here, R ⁵ and R ⁶ in formula (c) are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a carboxyl group, a cyano group, or —COOU (U is an alcohol residue). Or R ⁵ and R ⁶ are bonded to each other to represent a carboxylic anhydride residue represented by —C (═O) OC (═O) —.
When R ⁵ and R ⁶ are a group —COOU, the carboxyl group is an ester group, and the alcohol residue corresponding to U has, for example, about 1 to 8 carbon atoms that may be substituted. And an alkyl group, a 2-oxooxolan-3- or -4-yl group. Here, in the alkyl group, a hydroxyl group, an alicyclic hydrocarbon residue, or the like may be bonded as a substituent.
Specific examples when R ⁵ and R ⁶ are alkyl groups include a methyl group, an ethyl group, and a propyl group. Specific examples of the alkyl group to which a hydroxyl group is bonded include a hydroxymethyl group and 2-hydroxyethyl group. Group and the like.

Thus, specific examples of the norbornene structure represented by the formula (c), which is a monomer that gives a stable repeating unit to an acid, include the following compounds.
2-norbornene,
2-hydroxy-5-norbornene,
5-norbornene-2-carboxylic acid,
Methyl 5-norbornene-2-carboxylate,
2-hydroxy-1-ethyl 5-norbornene-2-carboxylate,
5-norbornene-2-methanol,
5-norbornene-2,3-dicarboxylic anhydride.

In addition, in U of —COOU of R ⁵ and R ^{6 in} the formula (c), if it is an acid-labile group such as an alicyclic ester in which the carbon atom adjacent to the oxygen atom is a quaternary carbon atom, Even though it has a norbornene structure, it is a repeating unit having an acid labile group. Examples of the monomer containing a norbornene structure and an acid labile group include, for example, 5-norbornene-2-carboxylic acid-t-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, and 5-norbornene. 2-carboxylate 1-methylcyclohexyl, 5-norbornene-2-carboxylic acid 2-methyl-2-adamantyl, 5-norbornene-2-carboxylic acid 2-ethyl-2-adamantyl, 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-adama) Chill) -1-methylethyl and the like.

  Furthermore, you may contain the repeating unit containing the repeating unit represented by a formula (b1), and a fluorine atom as an acid stable group.

[In the formula (b1),
R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group.
AR represents a linear, branched or cyclic hydrocarbon group having 1 to 30 carbon atoms, and at least one hydrogen atom 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 ^c ) —, and the hydrogen atom contained in the hydrocarbon group is a hydroxyl group or a straight chain. Or a branched or branched aliphatic hydrocarbon group having 1 to 6 carbon atoms. R ^c represents the same meaning as described above. ]

  Specific examples of the monomer that gives the repeating unit represented by the formula (b1) include the following monomers.

  The resin varies depending on the type of radiation for patterning exposure, the type of acid labile group, etc., but the content of repeating units derived from monomers having an acid labile group in the resin is usually 10 to 10. Adjust to the range of 80 mol%.

  As repeating units derived from monomers having acid labile groups, in particular, 2-alkyl-2-adamantyl methacrylate, 2-alkyl-2-adamantyl acrylate 1- (1-adamantyl) -1-alkyl methacrylate In the case of containing a repeating unit derived from alkyl, 2-alkyl-2-adamantyl methacrylate 1- (1-adamantyl) -1-alkylalkyl acrylate, 15 of all repeating units constituting the resin. When it is at least mol%, the resin has an alicyclic group, so that it has a sturdy structure, which is advantageous in terms of dry etching resistance of the resist to be provided.

  When an alicyclic compound having an olefinic double bond in the molecule and an aliphatic unsaturated dicarboxylic acid anhydride are used as monomers, they tend to be difficult to undergo addition polymerization. It is preferable to use in excess.

  As the monomer used, monomers having the same olefinic double bond but different acid labile groups may be used in combination, or monomers having the same acid labile group and different olefinic double bonds may be used in combination. Alternatively, monomers having different combinations of acid-labile groups and olefinic double bonds may be used in combination.

  The weight average molecular weight of the resin (B) is preferably 2,500 or more and 100,000 or less, more preferably 2,700 or more and 50,000 or less, and further preferably 3,000 or more and 40,000 or less. .

  The resist composition of the present invention preferably contains a basic compound. The basic compound is preferably a basic nitrogen-containing organic compound, more preferably an amine or ammonium salt. By adding a basic compound as a quencher, it is possible to improve the performance degradation due to the deactivation of the acid accompanying the holding after exposure. Specific examples of the basic compound used for the quencher include those represented by the following formulas.

In the formula, R ¹¹ , R ¹² and R ¹⁷ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has about 6 to 10 carbon atoms. Of carbon atoms. Further, at least one hydrogen atom on the alkyl group, cycloalkyl group or aryl group may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. Good. At least one hydrogen atom on the amino group may be independently substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹³ and R ¹⁴ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an alkoxy group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has 6 to 10 carbon atoms. The alkoxy group preferably has 1 to 6 carbon atoms. Alternatively, R ¹³ and R ¹⁴ may be bonded to form an aromatic ring.
At least one hydrogen atom on the alkyl group, cycloalkyl group, aryl group or alkoxy group is independently substituted with a hydroxyl group, an amino group or an alkoxy group having about 1 to 6 carbon atoms. Also good. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹⁵ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group or a nitro group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has 6 to 10 carbon atoms. The alkoxy group preferably has 1 to 6 carbon atoms.
At least one hydrogen atom on the alkyl group, cycloalkyl group, aryl group or alkoxy group is each independently substituted with a hydroxyl group, an amino group, or an alkoxy group having about 1 to 6 carbon atoms. May be. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹⁶ represents an alkyl group or a cycloalkyl group. The alkyl group preferably has about 1 to 6 carbon atoms, and the cycloalkyl group preferably has about 5 to 10 carbon atoms. At least one hydrogen atom on the alkyl group or cycloalkyl group may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹⁸ , R ¹⁹ and R ²⁰ each independently represents an alkyl group, a cycloalkyl group or an aryl group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has 6 to 10 carbon atoms. Has about carbon atoms. Furthermore, at least one hydrogen atom on the alkyl group, cycloalkyl group or aryl group may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. . At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

W represents an alkylene group, a carbonyl group, an imino group, a sulfide group or a disulfide group. The alkylene group preferably has about 2 to 6 carbon atoms.
Further, in R ^{11 to} R ²⁰ , any of those that can take both a linear structure and a branched structure may be used.
As an aromatic ring, the same thing as the aromatic hydrocarbon mentioned above etc. are mentioned.

  Specific examples of such compounds include hexylamine, heptylamine, octylamine, nonylamine, decylamine, aniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, diisopropylaniline, 1- or 2- Naphthylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3, 3'-diethyldiphenylmethane, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, N-methylaniline, piperidine, diphenylamine, triethylamine, trimethylamine, tripro Ruamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, Methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, N, N-dimethylaniline, 2,6-isopropylaniline, Midazole, pyridine, 4-methylpyridine, 4-methylimidazole, bipyridine, 2,2′-dipyridylamine, di-2-pyridyl ketone, 1,2-di (2-pyridyl) ethane, 1,2-di (4 -Pyridyl) ethane, 1,3-di (4-pyridyl) propane, 1,2-bis (2-pyridyl) ethylene, 1,2-bis (4-pyridyl) ethylene, 1,2-bis (4-pyridyl) Oxy) ethane, 4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide, 1,2-bis (4-pyridyl) ethylene, 2,2′-dipiconylamine, 3,3′-dipiconylamine, Tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetra-n-hexylammonium hydroxide Examples thereof include droxide, tetra-n-octylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-trifluoromethylphenyltrimethylammonium hydroxide, (2-hydroxyethyl) trimethylammonium hydroxide (common name: choline), and the like. Of these, diisopropylaniline is preferable.

  Further, a hindered amine compound having a piperidine skeleton as disclosed in JP-A-11-52575 can be used as a quencher.

The resist composition of the present invention preferably contains the resin in the range of about 80 to 99.9% by weight and the acid generator in the range of about 0.1 to 20% by weight based on the total solid content.
Moreover, when using the basic compound which is a quencher, it is preferable to contain in the range of about 0.01 to 1 weight% on the basis of the total solid content of a resist composition.
The resist composition may further contain small amounts of various additives such as sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers, and dyes as necessary.

  The resist composition of the present invention is usually used as a resist solution composition in a state in which each of the above components is dissolved in a solvent, and is usually used in industrial processes such as spin coating on a substrate such as a silicon wafer. Applied by. The solvent used here may be any solvent that dissolves each component, has an appropriate drying rate, and gives a uniform and smooth coating film after the solvent evaporates, and is usually used industrially in this field. A solvent can be used.

  For example, 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, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate And ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone, and cyclic esters such as γ-butyrolactone. These solvents can be used alone or in combination of two or more.

As a method of forming a pattern using the resist composition of the present invention,
(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 method including the process of developing the composition layer after a heating using a image development apparatus is mentioned.

  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. Examples of the exposure machine include an immersion exposure machine. 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.

  In addition, the resist composition of the present invention is particularly useful for chemically amplified photoresist compositions, and is widely used for semiconductor microfabrication, manufacturing of circuit boards such as liquid crystals and thermal heads, and other photofabrication processes. It can be suitably used for various applications. In particular, it can be used as a chemically amplified photoresist composition suitable for excimer laser lithography such as ArF and KrF, ArF immersion exposure lithography, and EUV exposure lithography. In addition to immersion exposure, it can also be used for dry exposure. Furthermore, it can be used for double imaging and is industrially useful.

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 of the resin is a value determined by gel permeation chromatography.

Apparatus: HLC-8120GPC (manufactured by Tosoh Corporation)
Column: 3 TSKgel Multipore HXL-M + guardcolumn (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 is NMR (GX-270 type or EX-270 type; manufactured by JEOL Ltd.), mass spectrometry (LC: Agilent 1100 type, MASS: Agilent LC / MSD type or LC / MSD TOF type) It confirmed using.

Synthesis of acid generator A1

  10.00 parts of compound (aa-1-b), 120.00 parts of monochlorobenzene and 16.0 parts of compound (aa-1-a) were charged, and 1.40 parts of sulfuric acid were charged at 23 ° C. with stirring. The temperature was raised to ° C and concentrated. To the obtained reaction product, 4.00 parts of molecular sieve (4A Wako Pure Chemical Industries, Ltd.) was added, dehydrated at 125 ° C. for 8 hours, and concentrated. To the obtained concentrate, 166 parts of chloroform and 83 parts of ion-exchanged water were added, washed, and separated to recover the organic layer. This washing with water was performed a total of 6 times. To the collected organic layer, 1.66 parts of activated carbon was added, stirred, and filtered. The collected filtrate was concentrated to obtain 42.26 parts of pale yellow oil. To the obtained pale yellow oil, 42.26 parts of acetonitrile was added, and after homogenization, 126.78 parts of methyl-t-butyl ether was added and left to stand after stirring. The lower layer separated into two layers was collected, and further, 42.26 parts of acetonitrile was added. After homogenization, 126.78 parts of methyl-t-butyl ether was added and left to stand after stirring. The lower layer separated into two layers was collected, concentrated, and filtered after stirring to obtain 8.53 parts (yield 20%) of compound (aa-1-1) as a white solid. Compound (aa-1-1) was designated as A1.

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 347.0
¹ H-NMR (chloroform-d, internal standard substance tetramethylsilane): δ (ppm) 1.77-1.79 (m, 1H), 2.03-2.07 (m, 1H), 2.16 -2.21 (m, 1H), 2.27-2.29 (m, 1H), 2.65 (m, 1H), 3.45-3.47 (m, 1H), 3.50-3 .53 (m, 1H), 4.77 (m, 1H), 4.82-4.83 (m, 1H), 7.71-7.81 (m, 15H)

Synthesis of acid generator A2
32.88 parts of compound (aa-2-b), 120.00 parts of monochlorobenzene and 16.00 parts of compound (aa-1-a) were charged, and 1.40 parts of sulfuric acid was charged at 23 ° C. with stirring. The temperature was raised to ° C and concentrated. To the obtained reaction product, 4.50 parts of molecular sieve (4A Wako Pure Chemical Industries, Ltd.) was added, dehydrated at 125 ° C. for 8 hours, and concentrated. To the obtained concentrate, 170 parts of chloroform and 85 parts of ion-exchanged water were added and washed, followed by liquid separation to recover the organic layer. This washing with water was performed a total of 6 times. To the collected organic layer, 1.50 parts of activated carbon was added, stirred, and filtered. After the collected filtrate was concentrated, 40 parts of acetonitrile was added to the resulting concentrate to dissolve it, and then concentrated, 100 parts of methyl-tert-butyl ether was added, stirred, and then separated into two layers. The liquid was removed and the lower layer was taken out and concentrated. After adding 60.00 parts of ethyl acetate to the obtained concentrated liquid and stirring, the supernatant liquid separated into two layers is removed, and the lower layer is taken out and concentrated to obtain the compound (aa-2-1). 8.64 parts were obtained. Compound (aa-2-1) was designated as A2.

MS (ESI (+) Spectrum): M ⁺ 305.1
MS (ESI (-) Spectrum): M ^- 347.0

Synthesis of acid generator A3
31.15 parts of compound (aa-3-b), 120.00 parts of monochlorobenzene and 16.00 parts of compound (aa-1-a) were charged, and 1.40 parts of sulfuric acid was charged at 23 ° C. with stirring. The temperature was raised to ° C and concentrated. To the obtained reaction product, 4.00 parts of molecular sieve (4A Wako Pure Chemical Industries, Ltd.) was added, dehydrated at 125 ° C. for 8 hours, and concentrated. To the obtained concentrate, 170 parts of chloroform and 85 parts of ion-exchanged water were added and washed, followed by liquid separation to recover the organic layer. This washing with water was performed a total of 6 times. To the collected organic layer, 1.50 parts of activated carbon was added, stirred, and filtered. After the collected filtrate was concentrated, 40 parts of acetonitrile was added to the resulting concentrate to dissolve it, and then concentrated, 100 parts of methyl-tert-butyl ether was added, stirred, and then separated into two layers. The liquid was removed and the lower layer was taken out and concentrated. After adding 60.00 parts of ethyl acetate to the obtained concentrated liquid and stirring, the supernatant liquid separated into two layers is removed, and the lower layer is taken out and concentrated to obtain the compound (aa-3-1). 6.84 parts were obtained. The compound (aa-3-1) was designated as A3.

MS (ESI (+) Spectrum): M ⁺ 280.1
MS (ESI (-) Spectrum): M ^- 347.0

Synthesis of acid generator A4
First, 26.17 parts of compound (aa-4-b), 120.00 parts of monochlorobenzene and 16.00 parts of compound (aa-1-a) were charged, and 1.40 parts of sulfuric acid was charged at 23 ° C. with stirring. The temperature was raised to ° C and concentrated. To the obtained reaction product, 4.00 parts of molecular sieve (4A Wako Pure Chemical Industries, Ltd.) was added, dehydrated at 125 ° C. for 8 hours, and concentrated. To the obtained concentrate, 170 parts of chloroform and 85 parts of ion-exchanged water were added and washed, followed by liquid separation to recover the organic layer. This washing with water was performed a total of 6 times. To the collected organic layer, 1.50 parts of activated carbon was added, stirred, and filtered. After the collected filtrate was concentrated, 40 parts of acetonitrile was added to the resulting concentrate to dissolve it, and then concentrated, 100 parts of methyl-tert-butyl ether was added, stirred, and then separated into two layers. The liquid was removed and the lower layer was taken out and concentrated. After adding 60.00 parts of ethyl acetate to the obtained concentrated liquid and stirring, the supernatant liquid separated into two layers is removed, and the lower layer is taken out and concentrated to obtain the compound (aa-4-1). 4.98 parts were obtained. Compound (aa-4-1) was designated as A4.

MS (ESI (+) Spectrum): M ^<+> 207.1
MS (ESI (-) Spectrum): M ^- 347.0

[Synthesis of Resin B1]
Monomer E, monomer F, monomer B, monomer C and monomer D were charged in a molar ratio of 30: 14: 6: 20: 30. Subsequently, 1.5 mass times dioxane was added with respect to the total mass of all the monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. And heated at 73 ° C. for about 5 hours. Thereafter, the reaction solution is purified by performing the operation of pouring into a large amount of methanol / water mixed solvent (4: 1) and precipitating three times, and the weight average molecular weight is about 8.1 × 10 ^3. The coalescence was obtained with a yield of 65%. The obtained copolymer has a repeating unit derived from each monomer of the following formula, and this was designated as resin B1.

[Synthesis of Resin Y1]
Monomer A, monomer B and monomer C were charged in a molar ratio of 50:25:25, and then 1.5 mass times dioxane was added to the total mass of all monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. This was heated at 77 ° C. for about 5 hours. Thereafter, the reaction solution is purified by pouring it into a large amount of methanol / water mixed solvent (3: 1) and precipitating three times, and the weight average molecular weight is about 8.0 × 10 ^3. The coalescence was obtained in 60% yield. This copolymer has a repeating unit derived from each monomer of the following formula, and this was designated as resin Y1.

[Synthesis of Resin B2]
Monomer A, monomer F, monomer B, monomer C and monomer D were charged at a molar ratio of 30: 14: 6: 20: 30. Subsequently, 1.5 mass times dioxane was added with respect to the total mass of all the monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. And heated at 78 ° C. for about 5 hours. Thereafter, the reaction solution is purified by pouring it into a large amount of methanol / water mixed solvent (4: 1) and precipitating three times, and the weight average molecular weight is about 7.2 × 10 ^3. The coalescence was obtained with a yield of 68%. The obtained copolymer has a repeating unit derived from each monomer of the following formula, and this was designated as resin B2.

Examples and Comparative Examples (Preparation of Resist Composition)
As shown in Table 1, a chemically amplified photoresist composition was prepared by filtering a mixture obtained by mixing and dissolving the following components through a fluororesin filter having a pore size of 0.2 μm.

<Acid generator>
X1:
A1:
A2:
A3:
A4:
<Quencher>
Q1: 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

(Evaluation of resist composition)
An organic antireflective coating composition (ARC-29; manufactured by Nissan Chemical Co., Ltd.) is applied to a silicon wafer and baked at 205 ° C. for 60 seconds to form an organic antireflective coating having a thickness of 78 nm. Formed.
Next, the chemical amplification photoresist 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 [FPA5000-AS3; manufactured by Canon Inc., NA = 0.75, 2 / 3Annular] on the silicon wafer on which the film of the chemically amplified photoresist composition is formed in this manner, the exposure amount is stepped. The line-and-space pattern was exposed with various changes.
After exposure, post-exposure baking (PEB) was performed for 60 seconds on a hot plate at the temperature described in the “PEB” column of Table 1, and further with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed.

  Resolution evaluation: 100 nm line and space pattern is exposed at an exposure amount of 1: 1, and the resist pattern is observed with a scanning electron microscope. A thing or a thing in which pattern collapse was observed was set as x.

  Mask error factor evaluation (MEF): exposure was performed with an exposure amount at which an 85 nm line and space pattern was 1: 1, and mask patterns with mask sizes of 90 nm, 95 nm, and 100 nm were formed, respectively. The mask size is plotted on the horizontal axis, and the line width of the line pattern formed using each mask pattern is plotted on the vertical axis. A straight line having a slope of 2.3 or less was evaluated as ○, and a straight line exceeding 2.3 was evaluated as ×.

Focus margin evaluation (DOF): A range in which the line width is 90 nm ± 5% when the focus is shaken with an exposure amount at which the line width of a line-and-space pattern with a mask size of 90 nm is 90 nm (approximately 85.5%). ˜94.5 nm) was used as a line width index, and those having a DOF of 0.60 μm or more were indicated by ◯, and those having a DOF of less than 0.60 μm were indicated by ×.
These results are shown in Table 2.

  According to the resist composition of the present invention, a pattern having an excellent shape, DOF and MEF can be formed.

Claims (6)

A resist composition comprising a salt represented by the formula (AA) and a resin having a repeating unit derived from the compound represented by the formula (II).
[In the formula (AA)
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —O— or It may be replaced by -CO-.
T is a group represented by the formula (T2).
[In the formula (T2),
The hydrogen atom contained in the ring includes a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, and glycidoxy -CH _2- which may be substituted with a group or an acyl group having 2 to 4 carbon atoms and is included in the ring is -CO-, -O- , -S-, -SO ₂ -or -N (R ^c )-May be replaced.
R ^c represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms.
* Represents a bond to ^{X 1.} ]
Z ⁺ represents an organic cation. ]
[In the formula (II),
R ³ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
X represents —CH ₂ — or —S—. ] X ¹ is, the resist composition according to claim 1 Symbol placement is a group represented by the formula (x-1).
[In the formula (x-1),
X ² represents a divalent saturated hydrocarbon group having 1 to 16 carbon atoms.
X ³ represents a single bond or a divalent saturated hydrocarbon group having 1 to 16 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group is —O—, —CO— or —N (R ^c The hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxyl group, a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms. Good. R ^c represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms.
m represents an integer of 0-2. ] X ¹ is, * - CO-O - ( * ^{is, -C (Q 1) (Q} 2) - represents a bond to) a is claim 1 or 2 resist composition. The resist composition according to any one of claims 1 to 3 , wherein Z ⁺ is an arylsulfonium cation. The resin according to any one of claims 1 to 4 , wherein the resin further has an acid-labile group and is insoluble or hardly soluble in an alkaline aqueous solution, and is a resin that can be dissolved in an alkaline aqueous solution by the action of an acid. Resist composition. Furthermore, the resist composition in any one of Claims 1-5 containing a basic compound.