JP6240414B2 - Resist composition and method for producing resist pattern - Google Patents

Description

  The present invention relates to a resist composition, a method for producing a resist pattern using the resist composition, and the like.

Patent Document 1 includes a structural unit represented by the formula (a1-1-3), a structural unit represented by the formula (a2-1-1), and a structural unit represented by the formula (a3-1-1). And a resist composition comprising a resin comprising a structural unit represented by formula (I-1) and an acid generator comprising a salt represented by formula (B1-X).
Further, it is known that when a resist pattern is formed from a resist composition by photolithography, a positive resist pattern is obtained when developed with an alkaline developer, and a negative resist pattern is obtained when developed with an organic solvent ( Non-patent document 1).

JP 2010-113334 A

Published by Techno Times Inc. Monthly Display '11 June p. 31

  An object of the present invention is to provide a resist composition capable of producing a resist pattern having excellent pattern collapse resistance (PCM).

The present invention includes the following inventions.
[1] A resist composition comprising a resin having a structural unit represented by formula (I) and an acid generator represented by formula (II).
[In the formula (I),
Ring T ¹ represents a sultone ring having 3 to 34 carbon atoms which may have a substituent.
R ³ represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ¹ represents an alkanediyl group having 1 to 6 carbon atoms. ]
[In the formula (II),
X ² represents an alkanediyl group having 1 to 6 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted with a hydroxy group or —OR ⁵ , and a methylene group constituting the alkanediyl group May be replaced by an oxygen atom or a carbonyl group.
R ⁴ and R ⁵ each independently represent a hydrocarbon group having 1 to 24 carbon atoms, and the hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, The methylene group contained in the group may be replaced with an oxygen atom or a carbonyl group.
Z ⁺ represents an organic cation. ]
[2] The method for producing a resist pattern according to [1], wherein the acid generator represented by the formula (II) is an acid generator represented by the formula (IIA).
[In formula (IIA), X ² and Z ⁺ represent the same meaning as described above.
R ⁶ represents a hydrocarbon group having 1 to 17 carbon atoms, the hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the methylene group constituting the hydrocarbon group is May be replaced by an oxygen atom or a carbonyl group.
R ⁷ represents an alkyl group having 1 to 6 carbon atoms.
R ⁸ represents a fluorinated alkyl group having 1 to 6 carbon atoms.
However, the total carbon number of R ⁶ , R ⁷ and R ⁸ is 19 or less. ]
[3] The resist composition according to [1] or [1], further containing a solvent.
[4] (1) A step of applying the resist composition according to any one of [1] to [3] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
(4) A method for producing a resist pattern, comprising: a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.

  According to the resist composition of the present invention, a resist pattern having excellent pattern collapse resistance can be produced.

<Resist composition>
The resist composition of the present invention comprises:
Resin (hereinafter sometimes referred to as “resin (A)”), and
It contains an acid generator represented by the formula (II) (hereinafter sometimes referred to as “acid generator (II)”).
The resist composition of the present invention preferably further contains a solvent (E).
The resist composition of the present invention preferably further contains a basic compound (C).

<Resin (A)>
The resin (A) includes a structural unit represented by the formula (I) (hereinafter sometimes referred to as “structural unit (I)”).
The resin (A) preferably further contains a structural unit having an acid labile group (hereinafter sometimes referred to as “structural unit (a)”), and a structural unit having no acid labile group (hereinafter “structural unit”). (S) "may be included).
In the present specification, the “acid labile group” is a group having a leaving group and forming a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group by contact with an acid. Means.

<Structural unit (I)>
The structural unit (I) is shown below.
[In the formula (I),
Ring T ¹ represents a sultone ring having 3 to 34 carbon atoms which may have a substituent.
R ³ represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ¹ represents an alkanediyl group having 1 to 6 carbon atoms. ]

The sultone ring of the ring T ¹ refers to a ring containing —SO ₂ —O— as an atomic group constituting the ring.
The sultone ring, for example, formula (T ¹ -1), formula (T ¹ -2), the ring can be mentioned formula (T ¹ -3) or formula (T ¹ -4). The sultone ring may be monocyclic but is preferably polycyclic. The polycyclic sultone ring means a bridged ring containing —SO ₂ —O— as an atomic group constituting the ring, and is represented by, for example, the formula (T ¹ -1) or the formula (T ¹ -2). Ring. Incidentally, sultone ring, as the ring represented by the formula (T ¹ -2), as an atomic group forming a ring, other than -SO ₂ -O-, may contain a further hetero atom. Examples of the hetero atom include an oxygen atom, a sulfur atom, and a nitrogen atom, and among them, an oxygen atom is preferable.
Examples of the substituent that the sultone ring may have include an alkyl group having 1 to 12 carbon atoms that may have a halogen atom or a hydroxy group, a halogen atom, a hydroxy group, a cyano group, and 1 to 12 carbon atoms. Examples thereof include an alkoxy group, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms, and an acyl group having 2 to 4 carbon atoms.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.
Examples of the alkyl group having a halogen atom include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group, perfluorohexyl group, A trichloromethyl group, a tribromomethyl group, a triiodomethyl group, etc. are mentioned.
Examples of the alkyl group having a hydroxy group include a hydroxymethyl group and a 2-hydroxyethyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Aryl groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl, phenanthryl. Group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl and the like.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group, and a naphthylethyl group.
Examples of the alkoxycarbonyl group include groups in which a carbonyl group is further bonded to an alkoxy group such as a methoxycarbonyl group or an ethoxycarbonyl group.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.

The alkyl group in the substituent of the ring represented by any of the formulas (T ¹ -1) to (T ¹ -4) is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group.
The alkyl group having a halogen atom or a hydroxy group is preferably a hydroxymethyl group, a hydroxyethyl group, a trifluoromethyl group, or the like.
The alkoxycarbonyl group preferably has 6 or less carbon atoms, and more preferably a methoxycarbonyl group.
In addition, as a sultone ring, the sultone ring which does not have a substituent is preferable from a viewpoint that manufacture of the compound which can derive | guide | derive structural unit (I) is easy.

The ring T ¹ is preferably a ring represented by the following formula (T1 ′).
[In the formula (T1 ′),
X ¹¹ each independently represents an oxygen atom, a sulfur atom or a methylene group.
R ⁴¹ is a halogen atom or an alkyl group having 1-12 carbon atoms which may have hydroxy group, a halogen atom, hydroxy group, aryloxy group, a cyano group, an alkoxy group having 1-12 carbon atoms, 6 carbon atoms 12 represents an aryl group having 12 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms, or an acyl group having 2 to 4 carbon atoms.
ma represents an integer of 0 to 9. When ma is 2 or more, the plurality of R ⁴¹ are the same or different.
* Represents a bond with an oxygen atom. ]

X ¹¹ is preferably an oxygen atom or a methylene group, more preferably an oxygen atom.
R ⁴¹ is preferably a C 1-12 alkyl group which may have a halogen atom or a hydroxy group.

Further, the ring T ¹ is preferably a ring represented by the formula (T1).
[In the formula (T1),
R ⁴ is an alkyl group having 1 to 12 carbon atoms which may have a halogen atom or a hydroxy group, a halogen atom, a hydroxy group, a cyano group, an alkoxy group having 1 to 12 carbon atoms, or an aryl having 6 to 12 carbon atoms. Group, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms, or an acyl group having 2 to 4 carbon atoms.
m represents an integer of 0 to 9. When m is 2 or more, the plurality of R ⁴ are the same or different.
* Represents a bond with an oxygen atom. ]
Ma in the formula (T1 ′) and m in the formula (T1) are preferably 0 or 1, and more preferably 0.

Examples of the ring represented by the formula (T1 ′) and the ring represented by the formula (T1) include the following rings.

Examples of the halogen atom for R ³ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkyl 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 group, 2-ethylhexyl. And alkyl groups such as a group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group.
Examples of the alkyl group having a halogen atom include trifluoromethyl group, 1,1,1-trifluoroethyl group, perfluoroethyl group, 1,1,1,2,2-pentafluoropropyl group, perfluoropropyl group, 1, 1,1,2,2,3,3-peptafluorobutyl group, perfluorobutyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, perfluoropentyl group, perfluoro Examples include fluorinated alkyl groups such as hexyl group, perfluoroheptyl group, and perfluorooctyl group.
Among these, R ³ is preferably an alkyl group having no halogen atom or a hydrogen atom, and more preferably a hydrogen atom or a methyl group.

Examples of the alkanediyl group of Z ¹ include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, and a pentane-1,5- Diyl group, 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 A linear alkanediyl group such as a group, heptadecane-1,17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group and propane-2,2-diyl group;
1-methylbutane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1, Branched alkanediyl groups such as a 4-diyl group.

Examples of the structural unit (I) include the following structural units.

Specific examples of the structural unit (I) include those in which the methyl group corresponding to R ³ is replaced by a hydrogen atom.

  The monomer for deriving the structural unit (I) can be produced, for example, by the method described in JP 2010-113334 A.

  The resin (A) is preferably a copolymer of a monomer that leads to the structural unit (I) and a monomer that leads to the structural unit (a) and / or a monomer that leads to the structural unit (s).

<Structural unit (a)>
The structural unit (a) is a structural unit having an acid labile group. Here, as described above, the “acid labile group” is a group that forms a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group upon contact with an acid.
Examples of the acid labile group include a group represented by the formula (1) and a group represented by the formula (2).
[In the formula (1), R ^a1 , R ^a2 and R ^a3 each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination thereof. R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms. * Represents a bond. ]
[In Formula (2), R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms. R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and —CH ₂ — constituting the hydrocarbon group and the divalent hydrocarbon group. May be replaced by -O- or -S-.

^Examples of the alkyl group represented by R ^a1 , R ^a2 and R ^a3 include 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 hydrocarbon group represented by R ^a1 , R ^a2 and R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups (* represents a bond). The alicyclic hydrocarbon group represented by R ^a1 , R ^a2 and R ^a3 preferably has 3 to 16 carbon atoms.
Examples of the group obtained by combining an alkyl group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, and a methylnorbornyl group.

Examples of —C (R ^a1 ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group include the following groups. The divalent hydrocarbon group preferably has 3 to 12 carbon atoms. In each formula, R ^a3 has the same meaning as described above, and * represents a bond to —O—.

Examples of the group represented by the formula (1) include a 1,1-dialkylalkoxycarbonyl group (a group in which R ^a1 , R ^a2 and R ^a3 are alkyl groups in the formula (1), preferably tert-butoxycarbonyl). Group), 2-alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and the carbon atom to which they are bonded form an adamantyl group, and R ^a3 is an alkyl group) and 1- (adamantan-1-yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

Examples of the hydrocarbon group represented by R ^{a1 ′} , R ^{a2 ′} and R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group obtained by combining these.
Examples of the alkyl group and alicyclic hydrocarbon group are the same as those described above.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.
Examples of the divalent hydrocarbon group formed by combining R ^{a2 ′} and R ^{a3 ′} include groups in which one hydrogen atom has been removed from the hydrocarbon groups of R ^{a1 ′ to} R ^{a3 ′} .
At least one of R ^{a1 ′} and R ^{a2 ′} is preferably a hydrogen atom.

Specific examples of the group represented by the formula (2) include the following groups. * Represents a bond.

  The monomer for deriving the structural unit (a) is preferably a monomer having an acid labile group and an ethylenically unsaturated bond, and more preferably a (meth) acrylic monomer having an acid labile group.

  Among the (meth) acrylic monomers having an acid labile group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferable. If a resin having a structural unit (a) having a bulky structure such as an alicyclic hydrocarbon group is used in the resist composition, the resolution of the resist pattern can be improved.

  As a structural unit derived from a (meth) acrylic monomer having a group represented by formula (1), preferably a structural unit represented by formula (a1-1) or a structure represented by formula (a1-2) Units are listed. These may be used alone or in combination of two or more. In this specification, the structural unit represented by the formula (a1-1) and the structural unit represented by the formula (a1-2) are represented by the structural unit (a1-1) and the structural unit (a1-2), respectively. The monomer that derives the structural unit (a1-1) and the monomer that derives the structural unit (a1-2) may be referred to as a monomer (a1-1) and a monomer (a1-2), respectively.

[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents a bond to —CO—. Represents a hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group obtained by combining these.
m1 represents the integer of 0-14.
n1 represents an integer of 0 to 10.
n1 ′ represents an integer of 0 to 3. ]

L ^a1 and L ^a2 are preferably —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, more preferably —O—. k1 is preferably an integer of 1 to 4, more preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
Examples of the alkyl group of R ^a6 and R ^a7 , the alicyclic hydrocarbon group, and the group obtained by combining these include the same groups as the groups represented by R ^a1 , R ^a2, and R ^a3 in formula (1). .
The alkyl group for R ^a6 and R ^a7 preferably has 6 or less carbon atoms.
The alicyclic hydrocarbon group of R ^a6 and R ^a7 preferably has 8 or less carbon atoms, more preferably 6 or less.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 ′ is preferably 0 or 1.

As a monomer (a1-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned. Among these, a monomer represented by any one of formula (a1-1-1) to formula (a1-1-8) is preferable, and any one of formula (a1-1-1) to formula (a1-1-4) is preferable. The monomer represented by is more preferable.

Examples of the monomer (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, and 1-ethylcycloheptan-1-yl (meth). Acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, 1-methylcyclohexane-1-yl (meth) acrylate, 1-isopropylcyclopentan-1-yl (meth) acrylate, 1-isopropylcyclohexane-1- And yl (meth) acrylate. Monomers represented by the formula (a1-2-1) to the formula (a1-2-12) are preferred, and the formula (a1-2-3) to the formula (a1-2-4) or the formula (a1-2-9) The monomer represented by formula (a1-2-10) is more preferable, and the monomer represented by formula (a1-2-3) or formula (a1-2-9) is more preferable.

  When the resin (A) contains the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is usually 10 to 95 mol with respect to all the structural units of the resin (A). %, Preferably 15 to 90 mol%, more preferably 20 to 85 mol%.

As a structural unit derived from a (meth) acrylic monomer having a group represented by the formula (2), a structural unit represented by the formula (a1-5) (hereinafter referred to as “structural unit (a1-5)”) There are).
[In the formula (a1-5),
R ³¹ represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ^a1 represents a single bond or * — [CH ₂ ] _k4 —CO—L ^a54 —. Here, k4 represents an integer of 1 to 4. * Represents a bond with L ^a51 .
L ^a51 , L ^a52 , L ^a53 and L ^a54 each independently represent —O— or —S—.
s1 represents an integer of 1 to 3.
s1 ′ represents an integer of 0 to 3. ]

In formula (a1-5), R ³¹ is preferably a hydrogen atom, a methyl group, or a trifluoromethyl group.
L ^a51 is preferably an oxygen atom.
One of L ^a52 and L ^a53 is preferably an oxygen atom and the other is a sulfur atom.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ^a1 is preferably a single bond or * —CH ₂ —CO—O—.

Examples of the monomer that leads to the structural unit (a1-5) include the following monomers.

  When resin (A) has a structural unit (a1-5), the content rate is preferable 1-50 mol% with respect to all the structural units of resin (A), and 3-45 mol% is more preferable. 5 to 40 mol% is more preferable.

<Structural unit (s)>
The monomer for deriving the “structural unit (s)” which is a structural unit having no acid labile group is not particularly limited as long as it is a monomer having no acid labile group, and a known monomer in the resist field can be used. .
As the structural unit (s), a structural unit having a hydroxy group or a lactone ring and having no acid labile group is preferable. A structure having a hydroxy group and having no acid labile group (hereinafter sometimes referred to as “structural unit (a2)”) and / or a lactone ring and having no acid labile group If a resin having a unit (hereinafter sometimes referred to as “structural unit (a3)”) is used for the resist composition, the resolution of the resist pattern and the adhesion to the substrate can be improved.

<Structural unit (a2)>
The hydroxy group contained in the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group.
When the resist composition is applied to KrF excimer laser exposure (248 nm), high energy beam exposure such as electron beam or EUV (extreme ultraviolet light), the structural unit (a2) having a phenolic hydroxy group as the structural unit (a2) ) Is preferably used. When applied to ArF excimer laser exposure (193 nm) or the like, the structural unit (a2) is preferably a structural unit (a2) having an alcoholic hydroxy group, and more preferably a structural unit (a2-1). As the structural unit (a2), one type may be contained alone, or two or more types may be used in combination.

Examples of the structural unit (a2) having an alcoholic hydroxy group include a structural unit represented by the formula (a2-1) (hereinafter sometimes referred to as “structural unit (a2-1)”).
[In the formula (a2-1),
L ^a3 represents —O— or ^* —O— (CH ₂ ) _k2 —CO—O—,
k2 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy 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 or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

As a monomer which introduce | transduces structural unit (a2-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. A monomer represented by any one of formula (a2-1-1) to formula (a2-1-6) is preferable, and represented by any one of formula (a2-1-1) to formula (a2-1-4). The monomer represented by Formula (a2-1-1) or Formula (a2-1-3) is more preferable.

  When resin (A) contains structural unit (a2-1), the content rate is 3 to 45 mol% normally with respect to all the structural units of resin (A), Preferably it is 1 to 40 mol%. More preferably, it is 1-35 mol%, More preferably, it is 2-20 mol%.

<Structural unit (a3)>
The lactone ring contained in the structural unit (a3) may be, for example, a monocycle such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, and a bridged ring including these monocyclic lactone ring structures. But you can. Among these lactone rings, a γ-butyrolactone ring or a bridged ring containing a γ-butyrolactone ring structure is preferable.

  The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), or the formula (a3-3). These 1 type may be contained independently and 2 or more types may be contained.

[In the formula (a3-1),
L ^a4 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents an integer of 0 to 5. When p1 is 2 or more, the plurality of R ^a21 are the same or different from each other.
In formula (a3-2),
L ^a5 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 represents an integer of 0 to 3. When q1 is 2 or more, the plurality of R ^a22 are the same or different from each other.
In formula (a3-3),
L ^a6 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
r1 represents an integer of 0 to 3. When r1 is 2 or more, the plurality of R ^a23 are the same or different from each other. ]

In Formula (a3-1), Formula (a3-2), and Formula (a3-3), L ^a4 , L ^a5, and L ^a6 are each independently preferably an oxygen atom or an integer of k3 of 1 to 4. A group represented by * —O— (CH ₂ ) _k3 —CO—O—, more preferably an oxygen atom and * —O—CH ₂ —CO—O—, still more preferably an oxygen atom.
R ^a18 , R ^a19 , R ^a20 and R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are each independently preferably an integer of 0 to 2, more preferably 0 or 1.

  Examples of the monomer that leads to the structural unit (a3) include monomers described in JP 2010-204646 A. Formula (a3-1-1) to Formula (a3-1-4), Formula (a3-2-1) to Formula (a3-2-4), and Formula (a3-3-1) to Formula (a3-3) -4) is preferred, and the monomers represented by formula (a3-1-1) to formula (a3-1-2) and formula (a3-2-3) to formula (a3-2-4) are preferred. The monomer represented by either is more preferable, and the monomer represented by the formula (a3-1-1) or the formula (a3-2-3) is more preferable.

  When the resin (A) includes the structural unit (a3), the content is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on all the structural units of the resin (A). More preferably, it is 10-60 mol%.

The content of the structural unit (I) in the resin (A) is usually 1 to 80 mol%, preferably 2 to 75 mol%, and preferably 5 to 65 mol% with respect to all the structural units of the resin (A). More preferred.
The resin (A) having the structural unit (I) at such a content rate is adjusted by adjusting the molar amount of the monomer used to derive the structural unit (I) with respect to the total molar amount of all monomers used in the production of the resin (A). Can be manufactured.

When the resin (A) is a resin composed only of the structural unit (I) and the structural unit (a), these contents are respectively relative to all the structural units of the resin (A).
Structural unit (I); 1 to 80 mol%
Structural unit (a); 20 to 99 mol% is preferred,
Structural unit (I); 2-75 mol%
Structural unit (a); 25 to 98 mol% is more preferred,
Structural unit (I); 5-65 mol%
The structural unit (a); 35 to 95 mol% is more preferable.

When the resin (A) is a resin composed of the structural unit (I), the structural unit (a), and the structural unit (s), these content rates are respectively based on the total structural units of the resin (A).
Structural unit (I); 1 to 80 mol%
Structural unit (a); 17-96 mol%
Structural unit (s); 3-82 mol% is preferable,
Structural unit (I); 2-75 mol%
Structural unit (a); 20-93 mol%
Structural unit (s); 5-78 mol% is more preferable,
Structural unit (I); 5-65 mol%
Structural unit (a); 30 to 90 mol%
The structural unit (s); 5 to 65 mol% is more preferable.

  The resin (A) preferably contains 15 mol% or more of structural units derived from the monomer having an adamantyl group (particularly the structural unit (a1-1)) with respect to the total structural units (a). When the content of the structural unit having an adamantyl group is large, the dry etching resistance of the resist pattern is improved.

The resin (A) is preferably a resin composed of the structural unit (a) and the structural unit (s).
The structural unit (a) is preferably at least one of the structural unit (a1-1) and the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group), more preferably the structural unit (a1- 1).
The structural unit (s) is preferably at least one of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably the structural unit (a2-1). The structural unit (a3) is preferably at least one of the structural unit (a3-1) and the structural unit (a3-2).

Each structural unit constituting the resin (A) may be used alone or in combination of two or more, and is produced by a known polymerization method (for example, radical polymerization method) using a monomer that derives these structural units. can do.
The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more, more preferably 4,000 or more), 50,000 or less (more preferably 30,000 or less, and further preferably 15,000 or less).

<Resin other than resin (A)>
The resist composition of the present invention is selected from resins other than the above-described resin (A1), for example, the above-described structural unit (a), structural unit (s), and structural units derived from known monomers used in this field. A resin having at least one selected from the above may be contained.
When the resist composition of this invention contains resin other than resin (A), the content rate is 0.1-50 mass% normally with respect to the total amount of resin contained in the resist composition of this invention. , Preferably it is 0.5-30 mass%, More preferably, it is 1-20 mass%.

  In the resist composition of the present invention, the total content of the resin (A) is preferably 80% by mass or more and 99.9% by weight or less in the solid content of the resist composition. In the present specification, the “solid content in the composition” means the total of resist composition components excluding the solvent (E) described later. The solid content in the composition and the resin content relative thereto can be measured, for example, by a known analytical means such as liquid chromatography or gas chromatography.

<Acid generator (II)>
The acid generator (II) is represented by the formula (II).
[In the formula (II),
X ² represents an alkanediyl group having 1 to 6 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted with a hydroxy group or —OR ⁵ , and a methylene group constituting the alkanediyl group May be replaced by an oxygen atom or a carbonyl group.
R ⁴ and R ⁵ each independently represent a hydrocarbon group having 1 to 24 carbon atoms, and the hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, The methylene group constituting the group may be replaced with an oxygen atom or a carbonyl group.
Z ⁺ represents an organic cation. ]

Examples of the alkanediyl group of X ² include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, and a pentane-1,5-diyl group. Hexane-1,6-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-2,2-diyl group, butane-1,3-diyl group, 2-methylpropane -1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group and the like.
Of these, a methylene group is preferable.

Examples of the group in which one or more methylene groups contained in the alkanediyl group are replaced with an oxygen atom or a carbonyl group include the following divalent groups. * Represents a bond with CF ₂ .

Examples of the group in which the hydrogen atom contained in the alkanediyl group is substituted with a hydroxy group or —OR ⁵ and one or more methylene groups contained in the alkanediyl group are replaced with oxygen atoms include the following groups: . * Represents a bond with CF ₂ .

The hydrocarbon group for R ⁴ and R ⁵ may be either saturated or unsaturated, for example, a linear or branched alkyl group or alkenyl group, a monocyclic or polycyclic alicyclic hydrocarbon group , Aromatic hydrocarbon groups and the like, and a combination of two or more of these groups may be used.
Examples of the linear alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.
Examples of the branched alkyl group include an isopropyl group, a sec-butyl group, and a tert-butyl group.
Examples of the linear or branched alkenyl group include a vinyl group and an α-methylvinyl group.
Examples of the monocyclic alicyclic hydrocarbon group include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.
Examples of the polycyclic alicyclic hydrocarbon group include a norbornyl group and an adamantyl group.
Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group, tolyl group, xylyl group, 2,6-diethylphenyl group, 2- And methyl-6-ethylphenyl.

The acid generator (II) is preferably an acid generator represented by the formula (IIA).
[In formula (IIA), X ² and Z ⁺ represent the same meaning as described above.
R ⁶ represents a hydrocarbon group having 1 to 17 carbon atoms, the hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the methylene group constituting the hydrocarbon group is May be replaced by an oxygen atom or a carbonyl group.
R ⁷ represents an alkyl group having 1 to 6 carbon atoms.
R ⁸ represents a fluorinated alkyl group having 1 to 6 carbon atoms.
However, the total carbon number of R ⁶ , R ⁷ and R ⁸ is 19 or less. ]

Examples of the hydrocarbon group for R ⁶ include the same groups as those for R ⁴ , and an alicyclic hydrocarbon group is preferable.
Examples of the group in which the methylene group constituting the hydrocarbon group is replaced with an oxygen atom or a carbonyl group include the following. * Represents a bond.
Examples of the alkyl group for R ⁷ include a methyl group, an ethyl group, a propyl group, and a butyl group.
As the fluorinated alkyl group for R ⁸ , a trifluoromethyl group, a perfluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, a perfluorobutyl group, 1,1,2,2,3,3, Examples include 4,4-octafluorobutyl group, and a trifluoromethyl group is preferable.

Examples of the acid generator (II) include the following salts.

Examples of Z ⁺ include organic onium cations such as organic sulfonium cations, organic iodonium cations, organic ammonium cations, benzothiazolium cations, and organic phosphonium cations. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, an arylsulfonium cation is more preferable, and a cation represented by any one of the formulas (b2-1) to (b2-4) [hereinafter, depending on the formula number Sometimes referred to as “cation (b2-1)”. ] Is more preferable.

In formula (b2-1) to formula (b2-4),
Each of R ^{b4 to} R ^b6 independently represents an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms; , R ^b4 and R ^b5 together form a ring containing a sulfur atom. The hydrogen atom contained in the aliphatic hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group, and the aromatic hydrocarbon The hydrogen atom contained in the group may be substituted with a halogen atom, a hydroxy group or an alkoxy group having 1 to 12 carbon atoms.
R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5. When m2 is 2 or more, the plurality of R ^b7 are the same or different from each other, and when n2 is 2 or more, the plurality of R ^b8 are the same or different from each other.
R ^b9 and R ^b10 each independently represent an aliphatic hydrocarbon group having 1 to 30 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or R ^b9 and R ^b10 are combined together. Together with the sulfur atom to which they are attached, forms a 3- to 12-membered ring (preferably a 3- to 7-membered ring). —CH ₂ — constituting the ring may be replaced by —O—, —SO— or —CO—.
R ^b11 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms.
R ^b12 represents an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms. The hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group has 1 to 12 carbon atoms. Or an alkoxycarbonyloxy group having 1 to 12 carbon atoms.
R ^b11 and R ^b12 may form a 3- to 12-membered ring (preferably a 3- to 7-membered ring) together with —CH—CO— to which they are bonded. —CH ₂ — constituting the ring may be replaced by —O—, —SO— or —CO—.
R ^{b13 to} R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b24 represents -S- or -O-.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, the plurality of R ^b13 are the same or different from each other. When p2 is 2 or more, the plurality of R ^b14 are the same or different from each other. When q2 is 2 or more, the plurality of R ^b15 are the same. Alternatively, when r2 is 2 or more, a plurality of R ^b16 are the same or different from each other, when s2 is 2 or more, a plurality of R ^b17 are the same or different from each other, and when t2 is 2 or more, a plurality of R ^{b16 b18} are the same or different from each other.

R ^b4 and R ^b5 may together form a 3- to 12-membered ring (preferably a 3- to 7-membered ring) with the sulfur atom to which they are bonded.

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, pentyl group, hexyl group, octyl group and 2- An ethylhexyl group is mentioned. In particular, the aliphatic hydrocarbon group represented by R ^{b9 to} R ^b12 preferably has 1 to 12 carbon atoms.
Examples of the aliphatic hydrocarbon group in which a hydrogen atom is substituted with an alicyclic hydrocarbon group include a 1- (adamantan-1-yl) alkane-1-yl group.
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an alkyl group. In this case, the carbon number of the alicyclic hydrocarbon group is 20 or less including the carbon number of the alkyl group. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups.
In particular, the alicyclic hydrocarbon group of R ^{b9 to} R ^b11 preferably has 4 to 12 carbon atoms.

  Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an alkyl group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-alkyladamantan-2-yl group, a methylnorbornyl group, and an isobornyl group. Can be mentioned.

Examples of the aromatic hydrocarbon group include phenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-adamantyl group. Substituted or unsubstituted phenyl groups such as phenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group; biphenylyl group, naphthyl group, phenanthryl group and the like.
As an aromatic hydrocarbon group by which the hydrogen atom was substituted by the alkoxy group, 4-methoxyphenyl group etc. are mentioned, for example.
Examples of the alkyl group in which a hydrogen atom is substituted with an aromatic hydrocarbon group, that is, an aralkyl group, include a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, and a naphthylethyl group.
In addition, when an alkyl group or an alicyclic hydrocarbon group is contained in an aromatic hydrocarbon group, a C1-C12 alkyl group and a C3-C18 alicyclic hydrocarbon group are preferable.

Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkylcarbonyloxy group include methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group. Group, pentylcarbonyloxy group, hexylcarbonyloxy group, octylcarbonyloxy group, 2-ethylhexylcarbonyloxy group and the like.

The ring containing a sulfur atom which may be formed by combining R ^b4 and R ^b5 is any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. As long as it contains one or more sulfur atoms, it may further contain one or more oxygen atoms. As the ring, a ring having 3 to 18 carbon atoms is preferable, and a ring having 4 to 18 carbon atoms is more preferable.

Examples of the ring formed together with the sulfur atom to which R ^b9 and R ^b10 are bonded include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium. A ring etc. are mentioned.
Examples of the ring formed with —CH—CO— in which R ^b11 and R ^b12 are bonded include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

Examples of the cation (b2-1) include the following cations.

Examples of the cation (b2-2) include the following cations.

Examples of the cation (b2-3) include the following cations.

  The acid generator (II) is a combination of the above anion and the above cation. These can be arbitrarily combined, and among them, the salt represented by the following is preferable.

The salt (II) can be obtained, for example, by reacting a salt represented by the formula (II-0-1) with a compound represented by the formula (II-0-2) in a solvent. Examples of the solvent include chloroform.
[Wherein, X ² , R ⁴ and Z ⁺ represent the same meaning as described above. ]

Examples of the salt represented by the formula (II-0-1) include salts represented by the following.

The compound represented by the formula (II-0-2) is obtained by reacting a salt represented by the formula (II-0-3) and a compound represented by the formula (II-0-4) in a solvent. Can be obtained.
Examples of the solvent include chloroform.
[Wherein R ⁴ represents the same meaning as described above. ]
Examples of the compound represented by the formula (II-0-3) include compounds represented by the following.

The salt represented by the formula (IIA) can be obtained, for example, by reacting the salt represented by the formula (IIA-1) with the compound represented by the formula (IIA-2) in a solvent. Examples of the solvent include chloroform.
[Wherein, X ² , R ⁶ , R ⁷ , R ⁸ and Z ⁺ represent the same meaning as described above. ]

The salt represented by the formula (IIA-1) is obtained by reacting the salt represented by the formula (IIA-3) with the compound represented by the formula (IIA-4) in a solvent in the presence of an acid catalyst. Can be manufactured. Examples of the solvent include dimethylformamide. Examples of the acid catalyst include p-toluenesulfonic acid.
[Wherein, X ² , R ⁷ , R ⁸ and Z ⁺ represent the same meaning as described above. ]
Examples of the salt represented by the formula (IIA-3) include salts represented by the following.
Examples of the compound represented by the formula (IIA-4) include ethyl trifluoropyruvate.

The compound represented by the formula (IIA-2) can be obtained by reacting the salt represented by the formula (IIA-5) and the compound represented by the formula (IIA-6) in a solvent. .
Examples of the solvent include chloroform.
[Wherein R ⁶ represents the same meaning as described above. ]
Examples of the compound represented by the formula (IIA-5) include compounds represented by the following.

  The salt (II) may be used alone or in combination of two or more.

<Acid generator other than salt (II)>
The resist composition may contain an acid generator other than the acid generator (II) described above (hereinafter sometimes referred to as “acid generator (B)”).
The acid generator (B) may be either nonionic or ionic. Nonionic acid generators include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4). -Sulfonate), sulfones (for example, disulfone, ketosulfone, sulfonyldiazomethane) and the like. Examples of the ionic acid generator include onium salts containing onium cations (for example, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts) and the like. Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

  Examples of the acid generator (B) include JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, JP-A-62-153853, JP-A-63-146029, US Pat. No. 3,779,778, US Pat. No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712 The compound which generate | occur | produces an acid by the radiation as described in etc. can be used.

  The acid generator (B) is preferably a fluorine-containing acid generator, more preferably a salt represented by the formula (B1) (hereinafter sometimes referred to as “salt (B1)”).

[In the formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a saturated hydrocarbon group having 1 to 24 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be replaced by a fluorine atom or a hydroxy group, and methylene constituting the saturated hydrocarbon group The group may be replaced by an oxygen atom or a carbonyl group.
Y represents a hydrogen atom, a fluorine atom, or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and the methylene group constituting the alicyclic hydrocarbon group is an oxygen atom, A sulfonyl group or a carbonyl group may be substituted.
Z1 ⁺ represents an organic cation. ]

Examples of the perfluoroalkyl group for Q ^b1 and Q ^b2 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluoro sec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, A perfluorohexyl group etc. are mentioned.
Q ^b1 and Q ^b2 are each independently preferably a trifluoromethyl group or a fluorine atom, more preferably a fluorine atom.

Examples of the saturated hydrocarbon group for L ^b1 include an aliphatic saturated hydrocarbon group such as a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic alicyclic saturated hydrocarbon group, A combination of two or more of these groups may be used.
Specifically, methylene group, ethylene 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, 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, Linear alkanediyl groups such as 17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group and propane-2,2-diyl group;
Butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4- Branched alkanediyl groups such as diyl groups;
Monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group Valent alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbon such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group, etc. Groups and the like.

Examples of the group in which the methylene group constituting the divalent saturated hydrocarbon group of L ^b1 is replaced by an oxygen atom or a carbonyl group are represented by any of formulas (b1-1) to (b1-7). Groups. In addition, Formula (b1-1)-Formula (b1-7) have described the right and left according to Formula (B1), and among two bonds represented by *, C (Q ^b1 ) binds to (Q ^b2 )-, and binds to -Y on the right. The same applies to specific examples of the following formulas (b1-1) to (b1-7).

In formula (b1-1) to formula (b1-7),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b4 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 20.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms.
L ^b6 represents a divalent saturated hydrocarbon group having 1 to 22 carbon atoms. However, the upper limit of the total carbon number of L ^b5 and L ^b6 is 22.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms.
L ^b8 represents a divalent saturated hydrocarbon group having 1 to 23 carbon atoms. However, the upper limit of the total carbon number of L ^b7 and L ^b8 is 23.
L ^b9 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b10 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 21.
L ^b11 and L ^b12 represent a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms. However, the upper limit of the total carbon number of L ^b11 , L ^b12 and L ^b13 is 19.
L ^b14 and L ^b15 each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms. However, the upper limit of the total carbon number of L ^b14 , L ^b15 and L ^b16 is 21.

Among them, L ^b1 is preferably any one of formula (b1-1) to formula (b1-4), more preferably formula (b1-1) or formula (b1-2), and still more preferably formula (b1-1). And particularly preferably a divalent group represented by the formula (b1-1) in which L ^b2 is a single bond or —CH ₂ —.

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.

Examples of the divalent group represented by the formula (b1-7) include the following.

Specific examples when the hydrogen atom contained in the saturated hydrocarbon group of L ^b1 is substituted with a fluorine atom or a hydroxy group include the following.

Examples of the alicyclic hydrocarbon group represented by Y include groups represented by formulas (Y1) to (Y26).

  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 of the alkyl group and alicyclic hydrocarbon group in Y include, for example, a halogen atom, a hydroxy group, an oxo group, an alkyl group having 1 to 12 carbon atoms, a hydroxy group-containing alkyl group having 1 to 12 carbon atoms, carbon C3-C16 alicyclic hydrocarbon group, C1-C12 alkoxy group, C6-C18 aromatic hydrocarbon group, C7-C21 aralkyl group, C2-C4 acyl group , Glycidyloxy group or — (CH ₂ ) _j2 —O—CO—R ^b1 group (wherein R ^b1 is an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, or carbon Represents an aromatic hydrocarbon group of formula 6 to 18. j2 represents an integer of 0 to 4).

Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of the hydroxy group-containing alkyl group include a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, anthryl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group; tolyl group, xylyl group, cumenyl group, mesityl group. , Aryl groups such as biphenyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl, and the like.
Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, naphthylmethyl group, and naphthylethyl group.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.

Examples of Y include the following.

  Y is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, more preferably a substituent (for example, an oxo group, a hydroxy group, etc.). A good adamantyl group, more preferably an adamantyl group, a hydroxyadamantyl group or an oxoadamantyl group.

The sulfonate anion in the salt (B1) is preferably an anion represented by the formula (b1-1-1) to the formula (b1-1-9). In the following formulas, the definitions of the symbols have the same meaning as described above, and R ^b2 and R ^b3 each independently represent an alkyl group having 1 to 4 carbon atoms (preferably a methyl group).
Specific examples of the sulfonate anion in the salt (B1) include anions described in JP 2010-204646 A.

Examples of the organic cation (Z1 ⁺ ) contained in the salt (B1) include an organic onium cation, such as an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation, and an organic phosphonium cation. It is an organic sulfonium cation or an organic iodonium cation, more preferably an arylsulfonium cation, and still more preferably the same as the cation represented by any one of the formulas (b2-1) to (b2-4) described above. Is.

  Examples of the salt (B1) include salts represented by formulas (B1-1) to (B1-20), respectively. Among them, those containing an arylsulfonium cation are preferable. Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), Formula (B1-7), Formula (B1-11) ), Formula (B1-12), Formula (B1-13), Formula (B1-14), Formula (B1-18), Formula (B1-19), or Formula (B1-20). More preferred are salts.

When the resist composition contains only the acid generator (II) as the acid generator, the content of the acid generator (II) is preferably 1% by mass or more (more preferably) with respect to the resin (A). 3% by mass or more), preferably 30% by mass or less (more preferably 25% by mass or less).
When the resist composition contains the acid generator (II) and the acid generator (B), the total content of the acid generator (II) and the acid generator (B) is based on the resin (A). Preferably, it is 1% by mass or more (more preferably 3% by mass or more), preferably 40% by mass or less (more preferably 35% by mass or less).
The content ratio (mass ratio) between the acid generator (II) and the acid generator (B) is, for example, 5:95 to 95: 5, preferably 10:90 to 90:10, and more preferably 15: 85-85: 15.

<Solvent (E)>
The content of the solvent (E) is, for example, 90% by mass or more in the resist composition, preferably 92% by mass or more, more preferably 94% by mass or more, for example 99.9% by mass or less, preferably 99% by mass or less. It is. The content rate of a solvent (E) can be measured by well-known analysis means, such as a liquid chromatography or a gas chromatography, for example.

  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 may contain individually by 1 type and may contain 2 or more types.

<Basic compound (C)>
The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines. The basic compound (C) is preferably a compound represented by any one of the formulas (C1) to (C8) and (C1-1), more preferably represented by the formula (C1-1). The compound which is made is mentioned.

[In formula (C1), R ^c1 , R ^c2 and R ^c3 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or 6 to 6 carbon atoms. 10 represents an aromatic hydrocarbon group, and the hydrogen atom contained in the alkyl group and the alicyclic hydrocarbon group may be substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms, The hydrogen atom contained in the aromatic hydrocarbon group is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms. It may be substituted with a group hydrocarbon group. ]

[In Formula (C1-1), R ^c2 and R ^c3 represent the same meaning as described above.
R ^c4 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
m3 represents an integer of 0 to 3, and when m3 is 2 or more, the plurality of R ^c4 are the same or different from each other. ]

[In Formula (C2), Formula (C3) and Formula (C4), R ^c5 , R ^c6 , R ^c7 and R ^c8 each independently represent the same meaning as R ^c1 .
R ^c9 represents an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 6 carbon atoms, or an alkanoyl group having 2 to 6 carbon atoms.
n3 represents an integer of 0 to 8, and when n3 is 2 or more, the plurality of R ^c9 are the same or different from each other. ]

[In Formula (C5) and Formula (C6), R ^c10 , R ^c11 , R ^c12 , R ^c13 and R ^c16 each independently represent the same meaning as R ^c1 .
R ^c14 , R ^c15 and R ^c17 each independently represent the same meaning as R ^c4 .
o3 and p3 each independently represent an integer of 0 to 3, and when o3 is 2 or more, the plurality of R ^c14 are the same or different from each other, and when p3 is 2 or more, the plurality of R ^c15 are the same as each other Or different.
L ^c1 represents an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

Wherein (C7) and formula ^{(C8), R c18, R} c19 and R ^c20 in each occurrence independently represent the same meaning as R ^c4.
q3, r3 and s3 each independently represent an integer of 0 to 3, and when q3 is 2 or more, the plurality of R ^c18 are the same or different from each other, and when r3 is 2 or more, the plurality of R ^c19 are When the same or different from each other and s3 is 2 or more, the plurality of R ^c20 are the same or different from each other.
L ^c2 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

In formula (C1) to formula (C8) and formula (C1-1), the alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, alkoxy group, alkanediyl group are the same as those described above. Is mentioned.
Examples of the alkanoyl group include acetyl group, 2-methylacetyl group, 2,2-dimethylacetyl group, propionyl group, butyryl group, isobutyryl group, pentanoyl group, and 2,2-dimethylpropionyl group.

  Examples of the compound represented by the formula (C1) include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N- Dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tri Pentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyl Hexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonyl Amine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2- Examples include diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and preferably diisopropyl. Piruanirin. Particularly preferred include 2,6-diisopropylaniline.

Examples of the compound represented by the formula (C2) include piperazine.
Examples of the compound represented by the formula (C3) include morpholine.
Examples of the compound represented by the formula (C4) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound represented by the formula (C5) include 2,2′-methylenebisaniline.
Examples of the compound represented by the formula (C6) include imidazole and 4-methylimidazole.
Examples of the compound represented by the formula (C7) include pyridine and 4-methylpyridine.
Examples of the compound represented by the formula (C8) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 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′-dipiconylamine, bipyridine and the like.

  As ammonium salts, tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3- (trifluoromethyl) phenyltrimethyl Ammonium hydroxide, tetra-n-butylammonium salicylate, choline and the like can be mentioned.

  The content of the basic compound (C) in the solid content of the resist composition is preferably about 0.01 to 5% by mass, more preferably about 0.01 to 3% by mass, and particularly preferably 0.8. It is about 01 to 1% by mass.

<Other components (hereinafter sometimes referred to as “other components (F)”)>
The resist composition may contain other components (F) as necessary. The other 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.

<Preparation of resist composition>
The resist composition includes a resin (A) and an acid generator (II), and a solvent (E), an acid generator (B), a basic compound (C) and other components (F) used as necessary. Can be prepared by mixing. The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select the suitable temperature range from the range of 10-40 degreeC according to the solubility with respect to the solvent (E), such as a kind, etc. of resin. An appropriate mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.
After mixing each component, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

<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 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
(4) The process of heating the composition layer after exposure, (5) The process of developing the composition layer after a heating is included.

  Application of the resist composition onto the substrate can be performed by a commonly used apparatus such as a spin coater. Examples of the substrate include an inorganic substrate such as a silicon wafer. Before applying the resist composition, the substrate may be washed or an antireflection film or the like may be formed.

The composition layer is formed by drying the composition after application. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), or using a decompression device. The heating temperature is preferably 50 to 200 ° C., for example, and the heating time is preferably 10 to 180 seconds, for example. The pressure during drying under reduced pressure is preferably about 1 to 1.0 × 10 ⁵ Pa.

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

  The composition layer after exposure is subjected to heat treatment (so-called post-exposure baking) in order to promote the deprotection group reaction of the resin (A). 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 a developer using a developing device. Examples of the developing method include a dipping method, a paddle method, a spray method, and a dynamic dispensing method. The development temperature is preferably 5 to 60 ° C., and the development time is preferably 5 to 300 seconds.

When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer 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). The alkali developer may contain a surfactant.
It is preferable to wash the resist pattern with ultrapure water after development, and then remove the water remaining on the substrate and the pattern.

In the case of producing a negative resist pattern from the resist composition of the present invention, a developer containing an organic solvent as a developer (hereinafter sometimes referred to as “organic developer”) is used.
Organic solvents contained in the organic developer include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycols such as propylene glycol monomethyl ether Examples include ether solvents; amide solvents such as N, N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
In the organic developer, the content of the organic solvent is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and still more preferably only the organic solvent.
Among them, the organic developer is preferably a developer containing butyl acetate and / or 2-heptanone. In the organic developer, the total content of butyl acetate and 2-heptanone is preferably 50% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and substantially butyl acetate and / or 2 -More preferred is heptanone alone.
The organic developer may contain a surfactant. The organic developer may contain a trace amount of water.
At the time of development, the development may be stopped by substituting a solvent of a different type from the organic developer.

It is preferable to wash the developed resist pattern with a rinse solution. The rinsing liquid is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, and an alcohol solvent or an ester solvent is preferable.
After the cleaning, it is preferable to remove the rinse solution remaining on the substrate and the pattern.

<Application>
The resist composition of the present invention is a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, particularly a liquid. It is suitable as a resist composition for immersion exposure and useful for fine processing of semiconductors.

The present invention will be described more specifically with reference to examples. In the examples, “%” and “parts” representing the content or amount used are based on mass unless otherwise specified.
The structure of the compound was confirmed by MASS (LC: Agilent 1100 type, MASS: Agilent LC / MSD type or LC / MSD TOF type).
The weight average molecular weight is a value determined by gel permeation chromatography under the following conditions.
Apparatus: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore HXL-M x 3 + 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)

Synthesis Example 1: [Synthesis of salt represented by formula (II-1)]
A salt represented by the formula (II1-a) was synthesized by the method described in JP-A-2008-7409. 10.00 parts of salt represented by formula (II1-a), 50.00 parts of dimethylformamide, 4.18 parts of compound represented by formula (II1-b) and 0.70 parts of p-toluenesulfonic acid And stirred at 100 ° C. for 2 hours. To the obtained reaction solution, 200 parts of chloroform and 50 parts of ion-exchanged water were added, stirred for 30 minutes, and separated. This washing operation was repeated three times. The collected organic layer is concentrated, and the concentrate is fractionated in a column (Merck silica gel 60-200 mesh developing solvent: chloroform / methanol = 5/1) to give a salt represented by the formula (II1-c) 2. 43 parts were obtained.

0.63 parts of the compound represented by the formula (II1-d) and 10 parts of chloroform were charged, stirred at 23 ° C. for 30 minutes, 0.55 parts of the compound represented by the formula (II1-e) were charged, and 60 ° C. For 1 hour. The obtained reaction product was cooled to 23 ° C. and filtered to obtain a solution containing a compound represented by the formula (II1-f). A solution containing the compound represented by the formula (II1-f) was charged with 2.10 parts of the salt represented by the formula (II1-c) and stirred at 60 ° C. for 6 hours. To the obtained reaction product, 50 parts of chloroform and 20 parts of ion-exchanged water were charged, stirred and separated. Water washing was performed 5 times. The obtained organic layer was concentrated, and the resulting concentrate was dissolved in 20 parts of acetonitrile and concentrated. To the obtained concentrate, 30 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 1.69 parts of the salt represented by the formula (II-1).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 573.1

Synthesis Example 2: Synthesis of salt represented by formula (B1-5)
50.49 parts of the salt represented by the formula (B1-5-a) and 252.44 parts of chloroform are charged into a reactor, stirred at 23 ° C. for 30 minutes, and then represented by the formula (B1-5-b). 16.27 parts of the compound was added dropwise and stirred at 23 ° C. for 1 hour to obtain a solution containing a salt represented by the formula (B1-5-c). To the obtained solution containing the salt represented by the formula (B1-5-c), 48.80 parts of the salt represented by the formula (B1-5-d) and 84.15 parts of ion-exchanged water are added, The mixture was stirred at 23 ° C. for 12 hours. Since the resulting reaction solution was separated into two layers, the chloroform layer was separated and removed, and 84.15 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. To the obtained chloroform layer, 3.88 parts of activated carbon was added and stirred, followed by filtration. The collected filtrate was concentrated, 125.87 parts of acetonitrile was added to the resulting residue, and the mixture was stirred and concentrated. To the obtained residue, 20.62 parts of acetonitrile and 309.30 parts of tert-butyl methyl ether were added and stirred at 23 ° C. for 30 minutes, and then the supernatant was removed and concentrated. To the obtained residue, 200 parts of n-heptane was added, stirred at 23 ° C. for 30 minutes, and then filtered to obtain 61.54 parts of a salt represented by the formula (B1-5).
MASS (ESI (+) Spectrum): M ⁺ 375.2
MASS (ESI (−) Spectrum): M ⁻ 339.1

Synthesis of Resin (A) Compounds (monomers) used in the synthesis of resin (A) are shown below.
Hereinafter, these monomers are referred to as “monomer (a1-1-3)” or the like according to the formula number.

Synthesis Example 3 [Synthesis of Resin A1]
As the monomer, the monomer (a1-1-3), the monomer (a1-2-3), the monomer (a2-1-3), the monomer (a3-2-3) and the monomer (I-1) The ratio [monomer (a1-1-3): monomer (a1-2-3): monomer (a2-1-3): monomer (a3-2-3): monomer (I-1)] is 45:14: It mixed so that it might become 2.5: 22: 16.5, and the propylene glycol monomethyl ether acetate of 1.5 mass times of the total monomer amount was added, and it was set as the solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 0.95 mol% and 2.85 mol%, respectively, based on the total monomer amount, and these were added at 73 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / ion-exchanged water = 4/1 mixing solution to precipitate the resin, and this resin was filtered to obtain a resin A1 having a weight average molecular weight of 7.9 × 10 ³ (co-polymer). Polymer) with a yield of 65%. This resin A1 has the following structural units and was soluble in butyl acetate.

Synthesis Example 4 [Synthesis of Resin A2]
As monomers, monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-3), monomer (a3-2-3), monomer (a3-1-1) and monomer ( I-1) and its molar ratio (monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-2-3): monomer (a3 -1-1): The monomer (I-1) was mixed so as to be 45: 14: 2.5: 22: 6.5: 10, and the propylene glycol monomethyl ether acetate was 1.5 mass times the total monomer amount. In this solution, 0.95 mol% and 2.85 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total amount of monomers, respectively. And these The mixture was heated for about 5 hours at 3 ° C. The obtained reaction mixture was poured into a large amount of methanol / ion-exchanged water = 4/1 mixing solution to precipitate the resin, the resin was filtered, and the weight average molecular weight was 8. 0 × 10 ³ of resin A2 (copolymer) was obtained with a yield of 68%, and this resin A2 had the following structural units and was soluble in butyl acetate.

Synthesis Example 5 [Synthesis of Resin A3]
The monomer (a1-1-2), the monomer (a1-2-3), the monomer (a2-1-1), the monomer (I-1) and the monomer (a3-1-1) are mixed in a molar ratio [monomer (a1 -1-2): monomer (a1-2-3): monomer (a2-1-1): monomer (I-1): monomer (a3-1-1)] is 45: 14: 2.5: It mixed so that it might become a ratio of 10: 28.5, and also 1.5 mass times dioxane was mixed with this monomer mixture 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. It added so that it might become. This was polymerized by heating at 75 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. Again, the resin is dissolved in dioxane, poured into a large amount of methanol / water mixed solvent, the resin is precipitated, the precipitated resin is filtered and recovered twice, and purified by reprecipitation, weight average. A copolymer having a molecular weight of 7.9 × 10 ³ was obtained with a yield of 71%. This resin A3 had the following structural units and was soluble in butyl acetate.

Synthesis Example 6 [Synthesis of Resin A4]
As a monomer, a monomer (a1-1-3), a monomer (a2-1-1), a monomer (a3-1-1), a monomer (I-1), a molar ratio thereof [monomer (a1-1-3) : Monomer (a2-1-1): Monomer (a3-1-1): Monomer (I-1)] were mixed so that 51.7: 7.8: 23.3: 17.2. Dioxane of 1.5 mass times the amount of monomer was added to make a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators are added to the solution, respectively, with respect to the total monomer amount, and these are heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained is again dissolved in dioxane, and a solution obtained by pouring the solution into a methanol / water mixed solvent is precipitated twice, and the resin is filtered twice to perform a reprecipitation operation twice. 7 × 10 ³ resin A4 (copolymer) was obtained with a yield of 64%. This resin A4 has the following structural units.
Synthesis Example 7 [Synthesis of Resin A5]
As the monomer, monomer (a1-1-3), monomer (a1-5-1), monomer (a2-1-3), monomer (a3-2-3) and monomer (I-1) were used, The ratio [monomer (a1-1-3): monomer (a1-2-3): monomer (a2-1-3): monomer (a3-2-3): monomer (I-1)] is 45:14: It mixed so that it might become 2.5: 22: 16.5, and the propylene glycol monomethyl ether acetate of 1.5 mass times of the total monomer amount was added, and it was set as the solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 0.95 mol% and 2.85 mol%, respectively, based on the total monomer amount, and these were added at 73 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / ion-exchanged water = 4/1 mixing solution to precipitate a resin, and the resin was filtered to obtain a resin A5 having a weight average molecular weight of 8.1 × 10 ³ (co-polymer). Polymer) with a yield of 60%. This resin A5 had the following structural units and was soluble in butyl acetate.

Synthesis Example 8 [Synthesis of Resin A6]
As the monomer, monomer (a1-1-2), monomer (a1-5-1), monomer (a2-1-1), monomer (I-1) and monomer (a3-1-1) were used, The ratio [monomer (a1-1-2): monomer (a1-5-1): monomer (a2-1-1): monomer (I-1)): monomer (a3-1-1)] is 30:14 : 6: 20: 30, and 1.5 mass times the total monomer amount of propylene glycol monomethyl ether acetate was added to obtain a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was again dissolved in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by reprecipitation operation of filtering the resin twice. Resin A6 (copolymer) having a molecular weight of 7.7 × 10 ³ was obtained in a yield of 82%. This resin A6 has the following structural units.

<Preparation of resist composition>
Each of the components shown below was dissolved in a solvent in parts by mass shown in Table 1, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
Resins A1 to A6 synthesized in the above synthesis example
<Acid generator>
II1: Salt represented by formula (II-1) II2: Central Glass Co., Ltd.
B1-3: synthesized according to the example of JP 2010-152341 A
B1-5:
B1-X: synthesized according to the example of JP 2010-113334 A

<Basic compound: Quencher>
C1: 2,6-diisopropylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.)

<Solvent>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 3.5 parts

Examples 1-7 and Comparative Example 1
<Manufacture of negative resist pattern>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer, and baked under the conditions of 205 ° C. and 60 seconds, whereby an organic layer having a thickness of 78 nm was obtained. An antireflection film was formed. Next, the resist composition was spin-coated on the organic antireflection film so that the film thickness of the composition layer after drying (pre-baking) was 100 nm. After coating, the composition layer was formed on the silicon wafer by pre-baking on a direct hot plate for 60 seconds at the temperature described in the “PB” column of Table 1. The composition layer formed on the silicon wafer was subjected to an immersion exposure ArF excimer laser stepper [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized illumination], and a line and space pattern. Using a mask for forming (pitch 90 nm / line width 45 nm), the exposure was changed in stages and exposed. Note that ultrapure water was used as the immersion medium. After the exposure, post-exposure baking was performed for 60 seconds on the hot plate at the temperature described in the “PEB” column of Table 1. Next, the composition layer on the silicon wafer was subjected to paddle development at 23 ° C. for 20 seconds using butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developer to produce a negative resist pattern.
The obtained resist pattern was observed with a scanning electron microscope, and the exposure amount at which the line width and the space width of the line and space pattern were 1: 1 was defined as the effective sensitivity.

<Pattern collapse evaluation (PCM) evaluation>
Using a mask for forming a 45 nm 1: 1 line and space pattern (pitch 90 nm / line width 45 nm), the line pattern formed with an exposure amount higher than the effective sensitivity was observed. The case where the pattern disappearance due to falling or peeling was not observed even when the line width of the line pattern was thinner than 45 nm was marked as ◯, and the case where the pattern disappearing due to falling or peeling was observed even when the line width was 45 nm or more was marked as x. The results are shown in Table 2. The numbers in parentheses indicate the minimum line width (nm) of the resist pattern in which no pattern disappearance is observed.

Examples 8 to 14 and Comparative Example 2
Except that the developer was changed from n-butyl acetate to 2-heptanone (manufactured by Kyowa Hakko Co., Ltd.), the same operation as above was performed to produce a negative resist pattern, and the same evaluation as in Example 1 was performed. went. The results are shown in Table 3.

  From the above results, it can be seen that according to the resist composition of the present invention, a resist pattern can be produced with excellent pattern collapse resistance.

<Preparation of resist composition>
Each of the components shown below was dissolved in the following solvent in the parts by mass shown in Table 4 and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

Examples 15 to 17 and Comparative Example 3
<Manufacture of resist pattern>
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.
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 4. 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. Note that ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking (PEB) was performed for 60 seconds on a hot plate at the temperature described in the “PEB” column of Table 4, and then with an aqueous 2.38 mass% tetramethylammonium hydroxide solution for 60 seconds. Paddle development was performed.

<Pattern collapse evaluation (PCM) evaluation>
Using a line-and-space pattern mask reduced from the line width of 45 nm to every 1 nm, the line-and-space pattern of each line width is exposed at an exposure amount that can be resolved, and when the line-and-space pattern is obtained, the pattern of the resist pattern collapses Or the presence or absence of pattern peeling (presence or absence of pattern disappearance) was observed. The case where pattern disappearance due to falling or peeling was not observed even when the line width was thinner than 38 nm was designated as “◯”, and the case where pattern disappearance due to falling or peeling was observed with a line width of 38 nm or more was designated as “X”. The results are shown in Table 5. The numerical value in the parenthesis indicates the line width (nm).

  From the above results, it can be seen that according to the resist composition of the present invention, a resist pattern can be produced with excellent pattern collapse resistance.

  The resist composition of the present invention can produce a resist pattern having excellent pattern collapse resistance.

Claims (3)

Resin having a structural unit represented by formula (I) and a structural unit containing an adamantane ring having 2 or 3 hydroxy groups, an acid generator represented by formula (IIA), and an acid represented by formula (B1) A resist composition containing a generator.
[In the formula (I),
Ring T ¹ represents a sultone ring having 3 to 34 carbon atoms which may have a substituent.
R ³ represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ¹ represents an alkanediyl group having 1 to 6 carbon atoms. ]
[In the formula (IIA)
X ² represents an alkanediyl group having 1 to 6 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted with a hydroxy group or —OR ⁵ , and a methylene group constituting the alkanediyl group May be replaced by an oxygen atom or a carbonyl group.
R ⁵ represents a hydrocarbon group having 1 to 24 carbon atoms, the hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the methylene group contained in the hydrocarbon group is May be replaced by an oxygen atom or a carbonyl group.
R ⁶ represents a hydrocarbon group having 1 to 17 carbon atoms, the hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the methylene group constituting the hydrocarbon group is May be replaced by an oxygen atom or a carbonyl group.
R ⁷ represents an alkyl group having 1 to 6 carbon atoms.
R ⁸ represents a fluorinated alkyl group having 1 to 6 carbon atoms.
However, the total carbon number of R ⁶ , R ⁷ and R ⁸ is 19 or less.
Z ⁺ represents an organic cation. ]
[In the formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a saturated hydrocarbon group having 1 to 24 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be replaced by a fluorine atom or a hydroxy group, and methylene constituting the saturated hydrocarbon group The group may be replaced by an oxygen atom or a carbonyl group.
Y represents a hydrogen atom, a fluorine atom, or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and the methylene group constituting the alicyclic hydrocarbon group is an oxygen atom, A sulfonyl group or a carbonyl group may be substituted.
Z1 ⁺ represents an organic cation. ]   Furthermore, the resist composition of Claim 1 containing a solvent. (1) The process of apply | coating the resist composition of Claim 1 or 2 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
(4) A step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.