JP6134563B2 - 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 describes a resist composition comprising a resin composed of a structural unit represented by the formula (u-A) and a structural unit represented by the formula (u-C), and triphenylsulfonium triflate. ing.
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 2000-122294 A

Monthly display '11 June issue issued by Techno Times p. 31

  An object of the present invention is to provide a resist composition capable of producing a resist pattern having excellent line edge roughness (LER).

The present invention includes the following inventions.
[1] A resist composition comprising a resin comprising a structural unit represented by formula (I) and a structural unit having an acid labile group, and an acid generator represented by formula (II).
[In the formula (I),
R ¹ represents a C 1-6 alkyl group, a hydrogen atom or a halogen atom which may have a halogen atom.
A ¹ is a single bond, ^* —A ² —O—, ^* —A ² —CO—O—, ^* —A ² —CO—O—A ³ —CO—O— or ^* —A ² —O—CO. -A ³ represents a -O-.
* Represents a bond with -O-.
A ² and A ³ each independently represents an alkanediyl group having 1 to 6 carbon atoms. ]
[In the formula (II),
R ^b1 and R ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Ring ^{W b1} represents a heterocycle of the C 2 to C 36.
R ^b3 represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ^b4 represents a hydrocarbon group having 1 to 6 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
s represents an integer of 0 to 6, and when s is 2 or more, the plurality of R ^b4 are the same or different.
Z1 ⁺ represents an organic cation. ]
[2] A ¹ is a single bond or ^* —A ² —O— (A ² represents an alkanediyl group having 1 to 6 carbon atoms, and * represents a bond to —O—) [1. ] The resist composition of description.
[3] The resist composition according to [1] or [2], 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 step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including:

  According to the resist composition of the present invention, a resist pattern having excellent line edge roughness (LER) can be produced.

The term "(meth) acrylic monomer" as used herein means at least one monomer having a structure of "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- " . Similarly, “(meth) acrylate” and “(meth) acrylic acid” mean “at least one of acrylate and methacrylate” and “at least one of acrylic acid and methacrylic acid”, respectively.

<Resist composition>
The resist composition of the present invention comprises a resin comprising a structural unit represented by formula (I) and a structural unit having an acid labile group (hereinafter sometimes referred to as “resin (A)”), and formula (II) (Hereinafter sometimes referred to as “acid generator (II)”).

It is preferable that the resist composition of the present invention further contains a solvent (E).
The resist composition of the present invention may further contain a basic compound (C).

<Resin (A)>
The resin (A) has a structural unit represented by the formula (I) and a structural unit having an acid labile group, and may further have a structural unit having no acid labile group.
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 represented by formula (I)>
The resin (A) has a structural unit represented by the formula (I) (hereinafter sometimes referred to as “structural unit (I)”).
[In the formula (I),
R ¹ represents a C 1-6 alkyl group, a hydrogen atom or a halogen atom which may have a halogen atom.
A ¹ is a single bond, ^* —A ² —O—, ^* —A ² —CO—O—, ^* —A ² —CO—O—A ³ —CO—O— or ^* —A ² —O—CO. -A ³ represents a -O-.
* Represents a bond with -O-.
A ² and A ³ each independently represents an alkanediyl group having 1 to 6 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 for R ¹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, and n-hexyl group. , Preferably it is a C1-C4 alkyl group, More preferably, it is a methyl group or an ethyl group.
Examples of the alkyl group having a halogen atom of R ¹ include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group, perfluoro group. A hexyl group, a trichloromethyl group, a tribromomethyl group, a triiodomethyl group, etc. are mentioned.
R ¹ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group.

Examples of the alkanediyl group of A ² and A ³ 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 and hexane-1,6-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, etc. are mentioned.
A ¹ is preferably a single bond or ^* —A ² —CO—O—, more preferably a single bond, —CH ₂ —CO—O— or —C ₂ H ₄ —CO—O—. .

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

In the above structural unit, a structural unit in which a methyl group corresponding to R ¹ is replaced by a hydrogen atom can also be given as a specific example of the structural unit (I).

The structural unit (I) is derived from a compound represented by the formula (I ′) (hereinafter sometimes referred to as “compound (I ′)”).
[In formula (I ′), R ¹ and A ¹ represent the same meaning as described above. ]

Compound (I ′) [compound represented by formula (I′-1)] in which A ¹ is * —CH ₂ —CO—O— (* represents a bond to —CO—O—) is The compound represented by the formula (I′-1-a) and the compound represented by the formula (I′-1-b) can be produced in a solvent. Examples of the solvent used for the reaction include methylene chloride, tetrahydrofuran, acetonitrile and the like.
[Wherein R ¹ represents the same meaning as described above. ]

The compound represented by the formula (I′-1-a) is obtained by reacting the compound represented by the formula (I′-1-c) with the compound represented by the formula (I′-1-d). Can be manufactured.
[Wherein R ¹ represents the same meaning as described above. ]
This reaction is preferably carried out in the presence of a solvent such as methylene chloride, tetrahydrofuran or acetonitrile. In this reaction, a condensing agent such as dicyclohexylcarbodiimide may be used.

Examples of the compound represented by the formula (I′-1-c) include the following compounds. The compounds represented by formula (I′-1-c) and formula (I′-1-d) are easily available from the market.
If a compound having A ¹ and R ¹ corresponding to the target compound (I ′) is used as the compound represented by the formula (I′-1-c), the target compound (I ′) can be obtained. .

Examples of compound (I ′) include the following.

In the above compounds, compounds in which the methyl group corresponding to R ¹ is replaced with a hydrogen atom can also be mentioned as specific examples of the compound (I ′).

  The content of the structural unit (I) is preferably 1 to 80 mol%, more preferably 2 to 75 mol%, still more preferably 3 to 70 mol% with respect to all the structural units of the resin (A). %, Particularly preferably 5 to 65 mol%.

<Monomer (a1) having an acid labile group>
The “acid-labile group” means a group having a leaving group and leaving the leaving group upon contact with an acid to form a hydrophilic group (for example, a hydroxy group or a carboxy group). Examples of the acid labile group include 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 — contained in 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 a decahydronaphthyl group, an adamantyl group, a 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 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 (in the formula (1), R ^a1 , R ^a2 and R ^a3 are alkyl groups, preferably tert-butoxycarbonyl). Group), 2-alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom form an adamantyl group, and R ^a3 is an alkyl group) and 1- (adamantane) -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 ′} .

In Formula (2), it is preferable that at least one of R ^{a1 ′} and R ^{a2 ′} is a hydrogen atom.
Specific examples of the group represented by the formula (2) include the following groups. * Represents a bond.

  The acid labile monomer (a1) is preferably a monomer having an acid labile group and an ethylenically unsaturated bond, 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 the resin composition (A2) having a structural unit derived from an acid labile monomer (a1) 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. it can.

  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 those 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). Examples include acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, and 1-isopropylcyclopentan-1-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) includes a structural unit represented by the formula (a1-1) and / or a structural unit represented by the formula (a1-2), the total content thereof is the total structure of the resin (A). It is 10-95 mol% normally with respect to a unit, Preferably it is 15-90 mol%, More preferably, it is 20-85 mol%.

Examples of the acid labile monomer (a1) include a monomer represented by the formula (a1-5) which is a (meth) acrylic monomer having an acid labile group (hereinafter referred to as “monomer (a1-5)”). May be used).
In 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 a * — [CH ₂ ] _k4 —CO—L ^a34 — group. Here, k4 represents an integer of 1 to 4. * Represents a bond with L ^a31 .
L ^a31 , L ^a32 , L ^a33 and L ^a34 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 ^a31 is preferably an oxygen atom.
One of L ^a32 and L ^a33 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 (a1-5) include the following monomers.

  When the resin (A) has a structural unit derived from the monomer (a1-5), the content is preferably from 1 to 50 mol%, preferably from 3 to 45 mol, based on all structural units of the resin (A). % Is more preferable, and 5 to 40 mol% is more preferable.

<Structural unit without acid labile group>
The structural unit having no acid labile group (hereinafter sometimes referred to as “acid stable structural unit”) is derived from a monomer having no acid labile group (hereinafter sometimes referred to as “acid stable monomer”).
As an acid stable monomer, Preferably, the monomer which has a hydroxyl group or a lactone ring is mentioned. If a resin having a structural unit derived from an acid-stable monomer having a hydroxy group or an acid-stable monomer containing a lactone ring is used, the resolution of the resist pattern and the adhesion to the substrate can be improved.

<Acid-stable monomer having a hydroxy group>
When the resist composition is used for high energy beam exposure such as KrF excimer laser exposure (248 nm), electron beam or EUV (extreme ultraviolet light), it is referred to as an acid stable monomer having a hydroxy group (hereinafter referred to as “acid stable monomer (a2)”) Preferably, an acid stable monomer having a phenolic hydroxy group is used.
When the resist composition is used for ArF excimer laser exposure (193 nm) or the like, the acid stable monomer (a2) having a hydroxy group is preferably an acid stable monomer having a hydroxyadamantyl group represented by the formula (a2-1) Is used.
An acid stable monomer (a2) may be used individually by 1 type, and may use 2 or more types together.

Examples of the acid-stable monomer having a hydroxyadamantyl group include an acid-stable monomer represented by the formula (a2-1).
In 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.

Examples of the acid stable monomer represented by the formula (a2-1) include monomers described in JP 2010-204646 A. 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 the resin (A) contains a structural unit derived from the acid-stable monomer (a2), the content thereof is usually 1 to 45 mol%, preferably 1 to 45 mol% with respect to all the structural units of the resin (A). It is 40 mol%, More preferably, it is 1-35 mol%, More preferably, it is 2-20 mol%.

<Acid-stable monomer having a lactone ring>
The lactone ring possessed by the acid-stable monomer containing a lactone ring (hereinafter sometimes referred to as “acid-stable monomer (a3)”) is, for example, a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring. A monocyclic ring or a condensed ring of a monocyclic lactone ring and another ring may be used. Among these lactone rings, a γ-butyrolactone ring or a condensed ring of γ-butyrolactone ring and another ring is preferable. The acid stable monomer (a3) does not include the compound (I ′).

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

In formula (a3-1), formula (a3-2) and formula (a3-3),
L ^a4 , L ^a5 and L ^a6 each independently represent —O— or ^* —O— (CH ₂ ) _k3 —CO—O—.
k3 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a18 , R ^a19 and R ^a20 each independently represents a hydrogen atom or a methyl group.
R ^a21 represents an alkyl group having 1 to 4 carbon atoms.
p1 represents an integer of 0 to 5.
R ^a22 and R ^a23 each independently represent a carboxy group, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
q1 and r1 each independently represents an integer of 0 to 3. When p1 is 2 or more, a plurality of R ^a21 are the same or different, when q1 is 2 or more, a plurality of R ^a22 are the same or different, and when r1 is 2 or more, a plurality of R ^a23 are the same or different Different.

^Examples of the alkyl group for R ^a21 , R ^a22 and R ^a23 include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, and a sec-butyl group.

In formula (a3-1), formula (a3-2) and formula (a3-3), L ^a4 , L ^a5 and L ^a6 are each independently —O— or ^* —O— (CH ₂ ) _k3 —. CO-O- is preferable, and -O- is more preferable. k3 is preferably an integer of 1 to 4, more preferably 1.
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 0 to 2, more preferably 0 or 1.

  Examples of the acid stable monomer (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) contains a structural unit derived from the acid-stable monomer (a3), the content is usually 5 to 70 mol%, preferably 10 to 10%, based on all structural units of the resin (A). It is 65 mol%, More preferably, it is 10-60 mol%.

When the resin (A) is a resin composed only of the structural unit (I) and the acid labile structural unit, these contents are respectively relative to the total structural unit of the resin (A),
Structural unit (I); 1 to 80 mol%
Acid-labile structural unit; 20-99 mol%
Is preferred,
Structural unit (I); 5-65 mol%
Acid labile structural unit; 35-95 mol%
Is more preferable.

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

The resin (A) is preferably a resin comprising a structural unit (I), an acid labile structural unit, and an acid stable structural unit, that is, a compound (I ′), an acid labile monomer (a1), and an acid stable monomer. It is a copolymer.
The acid labile structural unit 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 acid stable structural unit is preferably at least one of a structural unit derived from the acid stable monomer (a2) and a structural unit derived from the acid stable monomer (a3). The acid stable monomer (a2) is preferably a monomer represented by the formula (a2-1). The acid stable monomer (a3) is preferably at least one of an acid stable monomer represented by the formula (a3-1) and an acid stable monomer represented by the formula (a3-2).

  The resin (A) may contain a structural unit derived from a monomer having an adamantyl group (particularly the structural unit (a1-1)) in an amount of 15 mol% or more based on the content of the acid labile structural unit. preferable. When the content of the structural unit having an adamantyl group is increased, the dry etching resistance of the resist pattern is improved.

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 may contain a resin other than the resin (A).
The resin other than the resin (A) is not particularly limited as long as the resin does not contain the structural unit (I). For example, in addition to the above-mentioned acid-labile structural unit and acid-stable structural unit, the resin is used in this field. Examples of the resin include structural units derived from known monomers.
When the resist composition of this invention contains resin other than resin (A), these content rates are 0.1-50 mass% normally with respect to the total amount of resin, Preferably 0.5-30 It is mass%, More preferably, it is 1-20 mass%.

  The content of the resin (A) is preferably 80% by mass or more and 99% by mass or less in the solid content of the resist composition. In the present specification, the “solid content of the resist composition” means the total amount of components excluding the solvent (E) from the total amount of the resist composition of the present invention. The solid content of the resist composition and the content of the resin (A) relative thereto can be measured, for example, by a known analysis means such as liquid chromatography or gas chromatography.

<Acid generator (II)>
The acid generator (II) contained in the resist composition of the present invention contains a salt represented by the formula (II).
[In the formula (II),
R ^b1 and R ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Ring ^{W b1} represents a heterocycle of the C 2 to C 36.
R ^b3 represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ^b4 represents a hydrocarbon group having 1 to 6 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
s represents an integer of 0 to 6, and when s is 2 or more, the plurality of R ^b4 are the same or different.
Z1 ⁺ represents an organic cation. ]
In the formula (II), a compound having a negative charge obtained by removing an organic cation represented by Z ¹⁺ having a positive charge may be referred to as a “sulfonate anion”.

Examples of the perfluoroalkyl group for R ^b1 and R ^b2 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group. And perfluorohexyl group.

Examples of the divalent saturated hydrocarbon group for L ^b1 include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and these A combination of two or more of the 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, propane-2,2-diyl group;
An alkyl group (particularly an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group); For example, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl A branched alkanediyl group such as a 2-methylbutane-1,4-diyl group;
Cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,2-diyl group, 1-methylcyclohexane-1,2-diyl group, cyclohexane-1,4-diyl group, cyclo A monocyclic alicyclic saturated hydrocarbon group which is a cycloalkanediyl group such as an octane-1,2-diyl group or a cyclooctane-1,5-diyl group;
A polycyclic group such as norbornane-2,3-diyl group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group, etc. An alicyclic saturated hydrocarbon group etc. are mentioned.
The divalent alicyclic hydrocarbon group may be a group obtained by removing any one hydrogen atom from a monovalent alicyclic hydrocarbon group described later.

The heterocyclic ring of ring W ^b1 may be any ring containing one or more nitrogen atoms, and may further contain one or more nitrogen atoms, one or more oxygen atoms, one or more sulfur atoms, and the like. Good. The heterocyclic ring may be an aromatic heterocyclic ring, or may have no aromaticity, and may be a monocyclic, polycyclic, condensed ring or bridged ring. .
Examples of the heterocyclic ring include the following rings. However, —CH ₂ — contained in these heterocyclic rings may be replaced by —O— or —CO—. Among these, a ring represented by the formula (W1), a ring represented by the formula (W2), and a ring represented by the formula (W3) are preferable. * Represents a bond to L ^b1 .

Examples of the hydrocarbon group for R ^b3 and R ^b4 include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group obtained by combining these.
Examples of the aliphatic hydrocarbon group include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, 2,2-dimethylethyl, 1-methylpropyl, and 2-methylpropyl. Group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, 1-ethylpropyl group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, n-hexyl group, 1 -Propylbutyl group, pentyl group, 1-methylpentyl group, 1,4-dimethylhexyl group, heptyl group, 1-methylheptyl group, octyl group, methyloctyl group, methylnonyl group, 2-ethylhexyl group, nonyl group, decyl And alkyl groups such as a group, an undecyl group, and a dodecyl group.

The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples thereof include monocyclic alicyclic hydrocarbon groups such as cycloalkyl groups (for example, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group). A polycyclic group such as a group in which a condensed cyclic aromatic hydrocarbon group is hydrogenated (for example, a hydronaphthyl group) or a bridged cyclic hydrocarbon group (for example, an adamantyl group, a norbornyl group, or a group represented by the following formula). An alicyclic hydrocarbon group is mentioned.
Examples of the group obtained by combining an aliphatic hydrocarbon group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, and a methylnorbornyl group.
Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, p-methylphenyl group, p-ethylphenyl group, p-tert-butylphenyl group, p-cyclohexylphenyl group, p-methoxyphenyl group, p- Examples include an adamantylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a biphenyl group, an anthryl group, a phenanthryl group, a 2,6-diethylphenyl group, and an aryl group such as 2-methyl-6-ethylphenyl.

In the acid generator represented by the formula (II), R ^b1 and R ^b2 are each independently preferably a trifluoromethyl group or a fluorine atom, more preferably a fluorine atom.

Examples of the group in which —CH ₂ — in the divalent saturated hydrocarbon group of L ^b1 is replaced by —O— or —CO— include formulas (L1-1) to (L1-6). . L ^b1 is preferably any of formula (L1-1) to formula (L1-4), more preferably formula (L1-1) or formula (L1-2). In addition, Formula (L1-1)-Formula (L1-6) have described the right and left according to Formula (II), and among two bonds represented by *, C (R ^b1 ) (R ^b2 ) — and on the right side with ring W ^b1 . The same applies to specific examples of the following formulas (L1-1) to (L1-6).

In formula (L1-1) to formula (L1-6),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^b5 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 and L ^b7 each independently represent a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b8 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 independently represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
L ^b10 represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
Among them, L ^b1 is preferably any one of formula (L1-1) to formula (L1-4), more preferably formula (L1-1) or formula (L1-2), and still more preferably formula (L1). -1) is a divalent group. Particularly preferably, L ^b2 is a single bond or a saturated hydrocarbon group having 1 to 6 carbon atoms, that is, * —CO—O— (CH ₂ ) _t — (t represents an integer of 0 to 6. * represents − A divalent group represented by the formula (L1-1) in which L ^b2 is a single bond or a methylene group, and particularly preferably represents a bond to C (R ^b1 ) (R ^b2 ) —, More preferably, it is a divalent group represented by the formula (L1-1) in which L ^b2 is a single bond, that is, * —CO—O—.

Examples of the divalent group represented by the formula (L1-1) include the following.

Examples of the divalent group represented by the formula (L1-2) include the following.

Examples of the divalent group represented by the formula (L1-3) include the following.

Examples of the divalent group represented by the formula (L1-4) include the following.

Examples of the divalent group represented by the formula (L1-5) include the following.

Examples of the divalent group represented by the formula (L1-6) include the following.

R ^b3 is preferably a hydrogen atom, a methyl group, an ethyl group or a tert-butoxycarbonyl group, and more preferably a hydrogen atom, a methyl group or a tert-butoxycarbonyl group.
s is preferably 0, but when s is an integer of 1 to 6, R ^b4 is preferably a methyl group, an ethyl group, a methylcarbonyloxy group (acetyloxy group), an ethylcarbonyloxy group, or the like. Can be mentioned.

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

Examples of Z1 ⁺ 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, and an arylsulfonium cation is more preferable.

Examples of Z1 ⁺ include cations represented by formulas (Z1) to (Z4).

In formula (Z1) to formula (Z4),
Do P ^{a to} P ^c each independently represent 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? , P ^a and P ^b may 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 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 aliphatic hydrocarbon group having 1 to 18 carbon atoms, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group. The hydrogen atom contained in the aromatic hydrocarbon group may be a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or It may be substituted with an alkoxy group having 1 to 12 carbon atoms.

P ⁴ and P ⁵ 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.
P ⁶ and P ⁷ each independently represent an aliphatic hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or P ⁶ and P ^{7 taken} together Forms a ring containing a sulfur atom to which.
P ⁸ represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
P ⁹ represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the aliphatic hydrocarbon group includes The hydrogen atom contained may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group is an aliphatic hydrocarbon group having 1 to 12 carbon atoms, It may be substituted with an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkylcarbonyloxy group having 2 to 12 carbon atoms.
P ⁸ and P ⁹ may be combined to form a ring containing —CH—CO— to which they are attached.

P < ¹⁰ > -P < ¹⁵ > represents a hydroxyl group, a C1-C12 aliphatic hydrocarbon group, or a C1-C12 alkoxy group each independently.
E represents -S- or -O-.
i, j, p, r, x and y each independently represents an integer of 0 to 5;
q represents 0 or 1;
v and w each independently represent an integer of 0 to 4.
When i is 2 or more, the plurality of P ⁴ are the same or different from each other. When j is 2 or more, the plurality of P ⁵ are the same or different from each other. When p is 2 or more, the plurality of P ¹⁰ are the same. Or, when r is 2 or more, a plurality of P ¹¹ are the same or different from each other, when v is 2 or more, a plurality of P ¹² are the same or different from each other, and when w is 2 or more, a plurality of P 11 ¹³ are the same or different from each other. When x is 2 or more, the plurality of P ¹⁴ are the same or different from each other, and when y is 2 or more, the plurality of P ¹⁵ are the same or different from each other.

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-ethylhexyl group. Is mentioned.
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.
Examples of the aliphatic hydrocarbon group in which a hydrogen atom is substituted with an aromatic hydrocarbon group include an aralkyl group, and specifically include a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, and a naphthylethyl group. Groups and the like.
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. And cycloalkyl groups such as groups. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups. * Represents a bond.
Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a 2-alkyladamantan-2-yl group, and a methyl group. A norbornyl group, an isobornyl group, etc. are mentioned.
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.
In addition, when the hydrogen atom contained in the aromatic hydrocarbon group is substituted with an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, the C1-C18 aliphatic hydrocarbon group and the C3-C18 The alicyclic hydrocarbon group is preferably substituted.

As an alkoxy group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, an n-hexoxy group, a heptoxy group, an octoxy group , 2-ethylhexoxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group and the like.
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 halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group, and a 2-ethylhexylcarbonyloxy group.

Examples of the ring and the P ^a and P ^b together form a monocyclic, polycyclic, aromatic or non-aromatic, it may be any of the rings of the saturated and unsaturated, sulfur atom In addition, one or more sulfur atoms and / or one or more oxygen atoms, that is, —O—, —S—, or —CO— may be further included. This ring includes a 3-membered ring to a 18-membered ring, preferably a 3-membered ring to a 12-membered ring or a 4- to 18-membered ring.
The ring formed by combining P ⁶ and P ⁷ may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings, and a sulfur atom If it contains one or more, it may further contain one or more sulfur atoms and / or one or more oxygen atoms, that is, —O—, —S—, or —CO—. This ring includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring.
The ring formed by combining P ⁸ and P ⁹ may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated, and —CH— As long as it contains CO-, it may further contain one or more sulfur atoms and / or one or more oxygen atoms, that is, -O-, -S-, -CO-. This ring includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring.

Examples of the ring formed together with the sulfur atom to which P ⁶ and P ⁷ are bonded include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring. Etc.
Examples of the ring formed with —CH—CO— to which P ⁸ and P ⁹ are bonded include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

Among the cations represented by the formulas (Z1) to (Z4), the formula (Z1) is preferable, the cation represented by the formula (Z5) is more preferable, and the triphenylsulfonium cation (in the formula (Z5), z1 = z2 = z3 = 0), in diphenyl tolyl sulfonium cation (formula (Z5), a z1 = z2 = 0, z3 = 1, P 3 is a methyl group.) or tri tolyl sulfonium cation (formula (Z5) in Z1 = z2 = z3 = 1 and P ¹ , P ² and P ³ are all methyl groups.

In formula (Z5),
P ^{1 to} P ³ are each independently a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Or two selected from P ^{1 to} P ³ may be combined to form a ring containing a sulfur atom.
z1, z2 and z3 each independently represents an integer of 0 to 5. When z1 is 2 or more, a plurality of ^{P 1} are the same or different, when z2 is 2 or more, ^{P 2} are the same or different, when z3 is 2 or more, a plurality of ^{P 3} are the same Or different.

The ring formed by combining two selected from P ^{1 to} P ³ may be any of monocyclic, polycyclic, aromatic and non-aromatic rings. As long as it contains the above, it may contain one or more sulfur atoms and / or one or more oxygen atoms.
Aliphatic hydrocarbon group of P ¹ to P ³ is preferably 1 to 12 carbon atoms, alicyclic hydrocarbon group is preferably 4 to 18 carbon atoms.
Among them, each of P ^{1 to} P ³ independently represents a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, or P ¹ two selected from to P ³ is represent together -O-, it is preferable to form a ring containing a sulfur atom. z1 to z3 are preferably each independently 0 or 1.

Examples of the cation represented by the formula (Z1) or the formula (Z5) include the following.

The following are mentioned as a specific example of the cation in which the ring containing a sulfur atom was formed among the cations represented by a formula (Z5).

Specific examples of the cation (Z1) include the following.

Specific examples of the cation (Z2) include the following.

Specific examples of the cation (Z3) include the following.

Specific examples of the cation (Z4) include the following.

  The salt represented by the formula (II) is a combination of the above-mentioned anion and organic cation. Although the above-mentioned anion and organic cation can be combined arbitrarily, the compound represented below is preferable. In the following formulae, the definition of the substituent has the same meaning as described above.

Furthermore, the following compounds are more preferable as the salt represented by the formula (II).

The salt represented by the formula (II) can be produced by a method known in the art.
For example, in the salt represented by the formula (II), the salt represented by the formula (IIa) in which L ^b1 is —CO—O— includes the salt represented by the formula (IIa-1) and the formula (IIa— It can manufacture by making the compound represented by 2) react in a solvent. In the following formulas, each symbol represents the same meaning as above unless otherwise noted.
Examples of the solvent include chloroform.
Examples of the compound represented by the formula (IIa-2) include 4-hydroxy-1-methylpiperidine, 4-hydroxy-2,2,6,6-tetramethylpiperidine, tropine and the like.
The salt represented by the formula (IIa-1) can be obtained by reacting the salt represented by the formula (IIa-3) with the compound represented by the formula (IIa-4).
The salt represented by the formula (IIa-3) can be synthesized, for example, by the method described in JP2008-13551A.

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

<Acid generator (B)>
The resist composition of the present invention may contain an acid generator other than the salt represented by the formula (II) described above (hereinafter sometimes referred to as “acid generator (B)”). A known acid generator can be used as the acid generator (B).
The acid generator (B) is classified into a nonionic type and an ionic type, and any of them may be used in the resist composition of the present invention.
Nonionic acid generators include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4). -Sulfonates), sulfones (e.g. disulfone, ketosulfone, sulfonyldiazomethane) and the like. The ionic acid generator is typically an onium salt containing an onium cation (for example, diazonium salt, phosphonium salt, sulfonium salt, iodonium salt). Examples of the 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 sulfonate represented by the formula (B1).

[In the formula (B1),
Q ¹ and Q ² each independently represents 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 constitutes the saturated hydrocarbon group. The methylene group may be replaced with 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.
Z ⁺ represents an organic cation. ]

Examples of the perfluoroalkyl group of Q ¹ and Q ² are the same as the perfluoroalkyl group of R ^b1 and R ^b2 in formula (II).
In formula (B1), Q ¹ and Q ² are each independently preferably a trifluoromethyl group or a fluorine atom, more preferably a fluorine atom.

Examples of the divalent saturated hydrocarbon group represented by L ^{b1 ′} include a linear alkanediyl group, a branched alkanediyl group, or 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;
An alkyl group (particularly an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group); For example, 1-methylbutane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4 A branched alkanediyl group such as a diyl group or 2-methylbutane-1,4-diyl group;
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 saturated hydrocarbon group represented by L ^{b1 ′ in} which the methylene group is replaced with an oxygen atom or a carbonyl group include formula (b1-1) to formula (b1-7). 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 ¹ ) Combined with (Q ² )-and combined with -Y on the right side. 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 carbon number of L ^{b3 ′} and L ^{b4 ′} is 20.
L ^{b5 ′} represents a divalent saturated hydrocarbon group having 1 to 22 carbon atoms.
L ^{b6 ′} and L ^{b7 ′} each independently represent a divalent saturated hydrocarbon group having 1 to 22 carbon atoms. However, the upper limit of the carbon number of L ^{b6 ′} and L ^{b7 ′} is 23.
L ^{b8 ′} represents a divalent saturated hydrocarbon group having 1 to 22 carbon atoms.
L ^{b9 ′} and L ^{b10 ′} each independently represent a divalent saturated hydrocarbon group having 1 to 18 carbon atoms. However, the upper limit of the carbon number of L ^{b9 ′} and L ^{b10 ′} is 20.
L ^{b11 ′} and L ^{b12 ′} represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^{b13 ′} represents a C 1-19 divalent aliphatic saturated hydrocarbon group. 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 aliphatic saturated hydrocarbon group having 1 to 20 carbon atoms.
L ^{b16 ′} represents a divalent aliphatic 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 the formulas (b1-1) to (b1-4), more preferably the formula (b1-1) or the formula (b1-2), and still more preferably the formula (b1- The divalent group represented by 1) is 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 in which the hydrogen atom contained in the aliphatic saturated hydrocarbon group of L ^{b1 ′} is substituted with a fluorine atom or a hydroxy group, and in addition to the fluorine atom or hydroxy group, the hydrogen atom is substituted with an oxygen atom or a carbonyl group Specific examples of the case include the following.

Examples of the alicyclic hydrocarbon group represented by Y include groups represented by the following 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 for the alicyclic hydrocarbon group represented by Y include 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, and 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, — (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. The alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, aralkyl group and the like which are the above substituents may further have a substituent. Examples of the substituent include an alkyl group, a halogen atom, a hydroxy group, and an oxo group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
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 a phenyl group, a naphthyl group, an anthranyl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group; a tolyl group, a xylyl group, a cumenyl group, and a mesityl group. , Aryl groups such as biphenyl group, anthryl group, 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 acyl group include an acetyl group, a propionyl group, and a butyryl group.

Examples of Y include the following. * Represents a bond to L ^{b1 ′} .

  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 represented by the formula (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).
The sulfonate anion in the salt represented by the formula (B1) may be an anion described in JP 2010-204646 A.

Cation Z ⁺ contained in the acid generator (B1) include the same as the cation Z1 ⁺ contained in the formula (II) described above.

  The acid generator (B1) is a combination of the above-described sulfonate anion and organic cation. The above-mentioned anion and cation can be arbitrarily combined, and preferably a combination of any one of anion (b1-1) to anion (b1-1-9) with cation (Z5) and anion (b1-1-3) ) To (b1-1-5) and a combination of a cation (Z3).

  The acid generator (B1) is preferably a salt represented by the formula (B1-1) to the formula (B1-20), more preferably an acid generator containing an arylsulfonium cation. (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), Formula (B1-7), Formula (B1-11), Formula (B1-12), Formula ( B1-13), a formula (B1-14), a formula (B1-18), a formula (B1-19), or a salt represented by formula (B1-20).

When the resist composition of the present invention contains only the acid generator (II) as an acid generator, the content thereof is preferably 1 part by mass or more (more preferably) with respect to 100 parts by mass of the resin (A). 3 parts by mass or more), preferably 40 parts by mass or less (more preferably 35 parts by mass or less).
Further, when the resist composition of the present invention contains the acid generator (B) in addition to the acid generator (II), the total content of the acid generator (II) and the acid generator (B). Is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 40 parts by mass or less (more preferably 35 parts by mass or less) with respect to 100 parts by mass of the resin (A). In this case, the content ratio (mass) of the acid generator (II) and the acid generator (B) is, for example, 5:95 to 95: 5, preferably 10:90 to 90:10, 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 (E) may contain 1 type independently, and may contain 2 or more types.

<Basic compound (hereinafter sometimes referred to as “basic compound (C)”)>
The resist composition of the present invention is a compound that acts as a quencher.
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 the formula (C1) to a compound represented by the formula (C8), more preferably a compound represented by the formula (C1-1). It is done.

[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. ]

[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. ]

[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 represents an integer of 0 to 3, and when o3 is 2 or more, the plurality of R ^c14 are the same or different, and when p3 is 2 or more, the plurality of R ^c15 are the same 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 represents an integer of 0 to 3, and when q3 is 2 or more, the plurality of R ^c18 are the same or different, and when r3 is 2 or more, the plurality of R ^c19 are the same. Or when different and when s3 is 2 or more, the plurality of R ^c20 are the same or different.
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 the formulas (C1) to (C8), examples of the alkyl group, the alicyclic hydrocarbon group, the aromatic hydrocarbon group, the alkoxy group, and the alkanediyl group are the same as those described above.
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 of this invention may contain the other component (F) as needed. The other component (F) is not particularly limited, and additives known in the resist field, for example, sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes and the like can be used.

<Preparation of resist composition>
The resist composition of the present invention comprises a resin (A), an acid generator (II), a solvent (E) used as necessary, an acid generator (B), a basic compound (C), and other components (F ) Can be prepared by mixing. The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select an appropriate temperature range from the range of 10-40 degreeC according to the kind etc. of resin, the solubility with respect to solvent (E), such as 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) A step of applying the resist composition of the present invention 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) 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 to form a composition layer from which the solvent has been removed. The temperature in this case is preferably about 50 to 200 ° C., for example. The 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 lasers such as those that convert wavelength of laser light from the laser and emit harmonic laser light in the far-ultraviolet region or vacuum ultraviolet region, those that irradiate electron beams or extreme ultraviolet light (EUV), etc. Can do.

  The composition layer after exposure is subjected to heat treatment (so-called post-exposure baking) in order to promote the deprotection group reaction. As heating temperature, it is about 50-200 degreeC normally, Preferably it is about 70-150 degreeC.

  The heated composition layer is usually developed using 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 these, as the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable.
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 surfactant is not particularly limited, and examples thereof include ionic or nonionic fluorine-based and / or silicon-based surfactants. 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 of the resin 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 monomer (M-K))
33.48 parts of the compound represented by the formula (K-1), 23.93 parts of dicyclohexylcarbodiimide and 40 parts of methylene chloride were charged into a reactor and mixed. After cooling the obtained mixture to about 0 ° C., 18.83 parts of the compound represented by the formula (K-2) was added, and the mixture was stirred for about 1 hour while maintaining about 0 ° C. The temperature was raised to 23 ° C. and the mixture was further stirred for 30 minutes. Insoluble matters were removed by filtration, and the obtained filtrate was concentrated to obtain 44.28 parts of a compound represented by the formula (K-3).

A reactor was charged with 19.42 parts of the compound represented by the formula (K-3) obtained as described above, 18.22 parts of the compound represented by the formula (K-4) and 200 parts of acetonitrile. Mixed. The resulting mixture was stirred at 50 ° C. for 3 hours. The obtained mixture was concentrated, 300 parts of chloroform and 150 parts of ion-exchanged water were added, and then the organic layer was recovered by a liquid separation operation. The recovered organic layer was washed with 150 parts of ion exchange water, and then the organic layer was concentrated. The concentrate is subjected to column fractionation (column fractionation conditions stationary phase: silica gel 60-200 mesh manufactured by Merck & Co., Ltd. developing solvent: ethyl acetate) to obtain 12.89 parts of a compound represented by the formula (M-K). It was.
MS (mass spectrometry): 308.1 (molecular ion peak)

Synthesis Example 2: Synthesis of salt represented by formula (II-1)
A salt represented by the formula (II-1-1) was synthesized by the method described in JP 2008-127367 A.
10.00 parts of a salt represented by the formula (II-1-1) and 60.00 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and a compound 4.44 represented by the formula (II-1-2). A solution containing a compound represented by the formula (II-1-3) was obtained by charging 1 part and stirring at 50 ° C. for 1 hour. To the obtained solution containing the compound represented by the formula (II-1-3), 2.63 parts of the compound represented by the formula (II-1-4) was charged and stirred at 23 ° C. for 1 hour. The obtained reaction mass was charged with 80 parts of chloroform and 30 parts of ion-exchanged water, and stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 25 parts of acetonitrile was added to the resulting concentrate to dissolve and concentrate. To the obtained residue, 30 parts of tert-butyl methyl ether was added, stirred, stirred for 30 minutes, and filtered to obtain 4.48 parts of the salt represented by the formula (II-1).

Identification of the salt represented by the formula (II-1);
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 272.0

Synthesis Example 3: Synthesis of salt represented by formula (II-2)
A salt represented by the formula (II-2-1) was synthesized by the method described in JP 2008-127367 A.
10.00 parts of a salt represented by the formula (II-2-1) and 60.00 parts of acetonitrile were charged and stirred at 40 ° C. for 30 minutes to give a compound 4.44 represented by the formula (II-2-2). A solution containing a compound represented by the formula (II-2-3) was obtained by stirring 1 part at 50 ° C. for 1 hour. To the obtained solution containing the compound represented by the formula (II-2-3), 3.22 parts of the compound represented by the formula (II-2-4) was charged and stirred at 23 ° C. for 1 hour. The obtained reaction mass was charged with 80 parts of chloroform and 30 parts of ion-exchanged water, and stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and the resulting concentrate was dissolved by adding 30 parts of acetonitrile and concentrated. To the obtained residue, 50 parts of tert-butyl methyl ether was added and stirred, stirred for 30 minutes, and filtered to obtain 7.79 parts of the salt represented by the formula (II-2).

Identification of a salt represented by formula (II-2);
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 298.1

Synthesis Example 4: Synthesis of salt represented by formula (II-3)
50.00 parts of the compound represented by the formula (II-3-1) and 250 parts of tetrahydrofuran were charged into a reactor, stirred at 30 ° C. for 30 minutes, and 50.23 parts of trimethylsilyl chloride was added dropwise. The obtained mixed liquid was cooled to 0 ° C., and 157.20 parts of a compound represented by the formula (II-3-2) (purity: 32%, manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise over 30 minutes. Furthermore, this was heated up to 23 degreeC and stirred at the same temperature for 1 hour. To the resulting reaction mixture, 125 parts of 1N hydrochloric acid was charged, stirred and allowed to stand, and separated to recover the aqueous layer. To the recovered aqueous layer, 125 parts of tert-butyl methyl ether was added, stirred and allowed to stand, and the aqueous layer was recovered by liquid separation. To the recovered aqueous layer, 125 parts of chloroform was added, stirred and allowed to stand, and separated to recover the organic layer. The collected organic layer was filtered, and the obtained filtrate was concentrated. The concentrated residue was charged with 28.33 parts of acetonitrile and 354.15 parts of tert-butyl methyl ether, stirred at 23 ° C. for 30 minutes, and the precipitated crystals were filtered, thereby being represented by the formula (II-3-3). Compound 53.00 parts was obtained.
13.12 parts of a compound represented by the formula (II-3-4) and 73.86 parts of chloroform were charged into a reactor, stirred at 30 ° C. for 30 minutes, and represented by the formula (II-3-3). 200.71 parts of salt and 62.27 parts of ion-exchanged water were added. Subsequently, 6.90 parts of 35% hydrochloric acid was added dropwise and stirred at 23 ° C. for 12 hours. To the resulting reaction mixture, 12.00 parts of 28% aqueous ammonia was added dropwise, and this was separated to recover the organic layer. The recovered organic layer was charged with 50 parts of ion-exchanged water and subjected to a total of five washing operations such as stirring, standing and liquid separation. The obtained organic layer was charged with 2.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, 30 parts of acetonitrile and 150 parts of tert-butyl methyl ether were added to the resulting concentrate, the mixture was stirred, filtered, and the salt 14.28 represented by the formula (II-3-5). Got a part.

  10.32 parts of a salt represented by the formula (II-3-5) and 61.91 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and a compound 4.44 represented by the formula (II-3-6). Prepared the department. By stirring this at 50 degreeC for 1 hour, the solution containing the compound represented by Formula (II-3-7) was obtained. In a solution containing the compound represented by the formula (II-3-7) thus obtained, 2.63 parts of the compound represented by the formula (II-3-8) was charged and stirred at 23 ° C. for 1 hour. To the obtained reaction mass, 100 parts of chloroform and 50 parts of ion-exchanged water were added, and the mixture was stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and the resulting concentrate was dissolved by adding 30 parts of acetonitrile and concentrated. To the obtained residue, 30 parts of tert-butyl methyl ether was added and stirred, stirred for 30 minutes, and filtered to obtain 10.81 parts of the salt represented by the formula (II-3).

Identification of a salt represented by formula (II-3);
MS (ESI (+) Spectrum): M ⁺ 277.1
MS (ESI (-) Spectrum): M ^- 272.0

Synthesis Example 5: 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, and 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 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 filtered to obtain 61.54 parts of the 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 (MA)” to “monomer (ML)” depending on the reference numerals.

[Synthesis of Resin A1]
As a monomer, a monomer (MG), a monomer (ME), a monomer (MB), a monomer (M-H), and a monomer (M-K) are used, and the molar ratio (monomer (MG) : Monomer (ME): Monomer (MB): Monomer (M-H): Monomer (M-K)) were mixed so that the ratio was 32: 7: 8: 43: 10. 1.5 mass times dioxane was added to make 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 dissolved again in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.6. A × 10 ³ resin A1 (copolymer) was obtained in a yield of 80%. This resin A1 has the following structural units.

[Synthesis of Resin A2]
As a monomer, a monomer (MF), a monomer (M-I), a monomer (M-J), a monomer (MD) and a monomer (M-K) are used, and the molar ratio (monomer (MF)) : Monomer (M-I): monomer (M-J): monomer (MD): monomer (M-K)) were mixed so that 45: 14: 2.5: 22.5: 16, Dioxane of 1.5 mass times the total monomer amount was added to make 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 73 ° 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 dissolved again in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 8.8. × 10 ³ of the resin A2 (copolymer) was obtained in 71% yield. This resin A2 has the following structural units.

[Synthesis of Resin A3]
As a monomer, a monomer (M−F), a monomer (M−I), a monomer (M−J), a monomer (M−D), a monomer (M−H), and a monomer (M−K) are used, and a molar ratio thereof. (Monomer (MF): Monomer (M-I): Monomer (M-J): Monomer (MD): Monomer (M-H): Monomer (M-K))) 45: 14: 2. It mixed so that it might become 5: 17.5: 5: 16, and the dioxane of 1.5 mass times the total monomer amount was added, and it was set as the 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 dissolved again in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 8.3. × 10 ³ of the resin A3 (copolymer) was obtained in 69% yield. This resin A3 has the following structural units.

[Synthesis of Resin A4]
As a monomer, a monomer (MF), a monomer (ML), a monomer (MJ), a monomer (MD), and a monomer (MK) are used, and the molar ratio [monomer (MF) : Monomer (ML): monomer (M-J): monomer (MD): monomer (M-K)] is mixed to be 45: 14: 2.5: 22.5: 16, A solution was prepared by adding propylene glycol monomethyl ether acetate of 1.5 mass times the total monomer amount. 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 A4 (copolymer) having a molecular weight of 8.2 × 10 ³ was obtained in a yield of 66%. This resin A4 has the following structural units.

[Synthesis of Resin A5]
As a monomer, a monomer (MG), a monomer (ML), a monomer (MB), a monomer (M-H), and a monomer (M-K) are used, and the molar ratio [monomer (MG) : Monomer (ML): monomer (MB): monomer (M-H): monomer (M-K)] to be 32: 7: 8: 43: 10 1.5 mass times propylene glycol monomethyl ether acetate was added to prepare 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 A5 (copolymer) having a molecular weight of 7.9 × 10 ³ was obtained in a yield of 82%. This resin A5 has the following structural units.

[Synthesis of Resin H1]
Monomer (MA) and monomer (MC) are used as monomers and mixed so that the molar ratio (monomer (MA): monomer (MC)) is 40:60. An amount of 1.5 mass times dioxane was added to prepare a solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 1.4 mol% and 4.2 mol%, respectively, based on the total monomer amount, and these were added at 70 ° C. Heated for about 5 hours. 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 dissolved again in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, and the reprecipitation operation of filtering the resin was performed twice, and the weight average molecular weight was 5.0. A × 10 ³ resin H1 (copolymer) was obtained in a yield of 92%. This resin H1 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>
A1 to A5, H1: Resin A1 to Resin A5, Resin H1
<Acid generator>
II-1:
II-2:
II-3:
B1-3: synthesized according to the example of JP 2010-152341 A
B1-5:
B2: Triphenylsulfonium triflate (manufactured by TPS-105 Midori Chemical Co., Ltd.)

<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 to 11 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. 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. ArF excimer laser stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, Annual σ _out = 0.85 σ _in = 0.65 XY-pol on a silicon wafer on which the composition layer is formed . Illumination], using a mask for forming a trench pattern (pitch 120 nm / trench width 40 nm), the exposure amount was changed stepwise to perform exposure. 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.

  In the obtained resist pattern, the exposure amount at which the width of the trench pattern was 40 nm was defined as effective sensitivity.

<Line edge roughness evaluation (LER)>
The side wall of the obtained resist pattern is observed with a scanning electron microscope, and the fluctuation width of the unevenness on the side wall is
○ that is 5 nm or less,
The thing exceeding 5 nm was set as x.
The results are shown in Table 2. The numerical value in the parenthesis represents the fluctuation width (nm).

Examples 12 to 22 and Comparative Example 2
Except for changing the developer to 2-heptanone (manufactured by Kyowa Hakko Co., Ltd.), the same operation as described above was performed to produce a negative resist pattern, and the same evaluation as in the examples was performed. The results are shown in Table 3.

  From the above results, it can be seen that the resist composition of the present invention can produce a negative resist pattern having excellent line edge roughness.

<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 23 to 25 and Comparative Example 3
<Manufacture of resist pattern and its evaluation>
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 (pre-baking) 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 to obtain a resist pattern.

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

<Line edge roughness evaluation (LER)>
The wall surface of the resist pattern after the lithography process was observed with a scanning electron microscope, and the fluctuation width (nm) of the unevenness on the side wall of the resist pattern was obtained. The results are shown in Table 5.

  The resist composition of the present invention can produce a resist pattern with good line edge roughness (LER), and can be used for semiconductor fine processing and the like.

Claims (4)

Acid-stable having a structural unit represented by formula (I), a structural unit having an acid labile group, a structural unit derived from an acid-stable monomer containing a polycyclic lactone ring, and a hydroxyadamantyl group containing two hydroxyl groups A resist composition comprising a resin containing a structural unit derived from a monomer and an acid generator represented by formula (II).
[In the formula (I),
R ¹ represents a C 1-6 alkyl group, a hydrogen atom or a halogen atom which may have a halogen atom.
A ¹ is a single bond, ^* —A ² —O—, ^* —A ² —CO—O—, ^* —A ² —CO—O—A ³ —CO—O— or ^* —A ² —O—CO. -A ³ represents a -O-.
* Represents a bond with -O-.
A ² and A ³ each independently represents an alkanediyl group having 1 to 6 carbon atoms. ]
[In the formula (II),
R ^b1 and R ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Ring ^{W b1} represents a heterocycle of the C 2 to C 36.
R ^b3 represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ^b4 represents a hydrocarbon group having 1 to 6 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
s represents an integer of 0 to 6, and when s is 2 or more, the plurality of R ^b4 are the same or different.
Z1 ⁺ represents an organic cation. ] A ¹ is a single bond or ^* -A ² -O- ^{(A 2} represents an alkanediyl group having 1 to 6 carbon atoms, * represents. A bond to -O-) of claim 1 wherein the Resist composition.   Furthermore, the resist composition of Claim 1 or 2 containing a solvent. (1) The process of apply | coating the resist composition as described in any one of Claims 1-3 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,
A method for producing a resist pattern including: