JP6135146B2 - Salt, resist composition and method for producing resist pattern - Google Patents

Description

  The present invention relates to a salt for an acid generator, a resist composition, and a method for producing a resist pattern.

また、特許文献２には、酸発生剤用の塩として、下記式で表される塩を含有するレジスト組成物が記載されている。

For example, Patent Document 1 describes a salt represented by the following formula.

Patent Document 2 describes a resist composition containing a salt represented by the following formula as a salt for an acid generator.

JP 2010-1000083 A JP 2007-145822 A

  In the conventional resist composition, the line edge roughness (LER) at the time of producing the resist pattern may not always be sufficiently satisfied.

［式（Ｉ）中、
Ｑ^１及びＱ^２は、同一又は相異なり、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、（１＋ｍ１）価の炭素数１〜２０の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子はフッ素原子又はヒドロキシ基に置き換わっていてもよく、該飽和炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｘ^１は、ハロゲン原子を表す。
ｍ１は、２又は３を表し、複数存在するＸ^１は、それぞれ独立に、同一であっても異なっていてもよい。
Ｚ^＋は、有機カチオンを表す。］
〔２〕 −Ｌ^１−（Ｘ^１）_ｍ１で示される基が、式（Ｌ^１−１）で表される基である〔１〕記載の塩。

［式（Ｌ^１−１）中、
Ｘ^０は、置換基を有していてもよい炭素数１〜１８の（１＋ｍ１）価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子はフッ素原子又はヒドロキシ基に置き換わっていてもよく、該飽和炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｘ^１及びｍ１は上記と同じ意味を表す。
＊は、Ｃ（Ｑ^１）（Ｑ^２）の炭素原子との結合手を表す。］
〔３〕Ｚ^＋が、アリールスルホニウムカチオンである前記〔１〕又は〔２〕記載の塩。
〔４〕前記〔１〕〜〔３〕のいずれか記載の塩を有効成分として含有する酸発生剤。
〔５〕前記〔４〕記載の酸発生剤と樹脂とを含有し、該樹脂は酸に不安定な基を有し、かつアルカリ水溶液に不溶又は難溶であり、酸と作用してアルカリ水溶液で溶解し得る樹脂であるレジスト組成物。
〔６〕さらに塩基性化合物を含有する前記〔５〕記載のレジスト組成物。
〔７〕（１）前記〔５〕又は〔６〕記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層に露光する工程、
（４）露光後の組成物層を加熱する工程及び
（５）加熱後の組成物層を現像する工程
を含むレジストパターンの製造方法。 The present invention includes the following inventions.
[1] A salt represented by the formula (I).

[In the formula (I),
Q ¹ and Q ² are the same or different and each represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a (1 + m1) -valent saturated hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be replaced by a fluorine atom or a hydroxy group, and the saturated hydrocarbon group May be replaced with an oxygen atom or a carbonyl group.
X ¹ represents a halogen atom.
m1 represents 2 or 3, and a plurality of X ¹ may be the same or different each independently.
Z ⁺ represents an organic cation. ]
[2] The salt according to [1], wherein the group represented by -L ^1- (X ¹ ) _m1 is a group represented by the formula (L ¹ -1).

[In the formula (L ¹ -1),
X ⁰ represents an optionally substituted (1 + m1) -valent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group is replaced with a fluorine atom or a hydroxy group. The methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
X ¹ and m ¹ represent the same meaning as described above.
* Represents a bond with a carbon atom of C (Q ¹ ) (Q ² ). ]
[3] The salt according to [1] or [2], wherein Z ⁺ is an arylsulfonium cation.
[4] An acid generator containing the salt according to any one of [1] to [3] as an active ingredient.
[5] The acid generator according to the above [4] and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an aqueous alkali solution, and acts on the acid to react with the aqueous alkali solution. A resist composition, which is a resin that can be dissolved in
[6] The resist composition according to [5], further containing a basic compound.
[7] (1) A step of applying the resist composition according to [5] or [6] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) A method for producing a resist pattern, comprising a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

  If a resist composition containing the salt of the present invention as an acid generator is used, a resist pattern can be produced with excellent line edge roughness (LER).

  In the present specification, unless otherwise specified, the following examples of substituents are applied to any chemical structural formula having the same substituents while appropriately selecting the number of carbon atoms. Among the aliphatic hydrocarbon groups, those that can be linear or branched, such as an alkyl group, include any of them. When stereoisomers exist, all stereoisomers are included. In the following examples of substituents, the numerical value attached to “C” indicates the number of carbon atoms of each group.

The hydrocarbon group includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group.
The aliphatic hydrocarbon group includes both a chain type and a cyclic type, and includes a combination of a chain type and an alicyclic aliphatic hydrocarbon group unless otherwise defined. Further, these aliphatic hydrocarbon groups may contain a carbon-carbon double bond in a part thereof, but a saturated group (aliphatic saturated hydrocarbon group) is preferable.

鎖式の脂肪族炭化水素基のうち４価のものとしては、アルキル基から水素原子を３個取り去ったアルカンテトライル基が挙げられる。アルカンテトライル基の具体例は、以下で表される４価の基などである。

Of the chain aliphatic hydrocarbon groups, the monovalent one typically includes an alkyl group. Specific examples of the alkyl group include a methyl group (C ₁ ), an ethyl group (C ₂ ), a propyl group (C ₃ ), a butyl group (C ₄ ), a pentyl group (C ₅ ), a hexyl group (C ₆ ), heptyl _(C 7), octyl _(C 8), decyl (C _10), dodecyl (C _12), hexadecyl (C _14), pentadecyl (C _15), hexyl decyl group (C _16), A heptadecyl group (C ₁₇ ) and an octadecyl group (C ₁₈ ).
Examples of the divalent group of chain aliphatic hydrocarbon groups include alkanediyl groups in which one hydrogen atom has been removed from an alkyl group. Specific examples of the alkanediyl group include 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 -1,17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group and propane-2,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1 , 3 Diyl, 2-methylpropane-1,2-diyl, pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group.
Examples of the trivalent group of chain aliphatic hydrocarbon groups include alkanetriyl groups in which two hydrogen atoms have been removed from an alkyl group. Specific examples of the alkanetriyl group include methanetriyl group, ethane-1,1,2-triyl group, ethane-1,2,2-triyl group, propane-1,2,3-triyl group, butane-1,2 , 4-triyl group, pentane-1,3,5-triyl group, heptane-1,4,7-triyl group, nonane-1,5,9-triyl group and trivalent groups represented by is there.

Examples of the tetravalent group of chain aliphatic hydrocarbon groups include alkanetetrayl groups in which three hydrogen atoms have been removed from an alkyl group. Specific examples of the alkanetetrayl group include a tetravalent group represented by the following.

  The cyclic aliphatic hydrocarbon group (hereinafter sometimes referred to as “alicyclic hydrocarbon group” in some cases) is typically a cycloalkyl group, and any of the monocyclic and polycyclic groups shown below can be used. Is also included.

As a monovalent alicyclic hydrocarbon group, a monocyclic aliphatic hydrocarbon group represents 1 hydrogen atom of a cycloalkane represented by the following formulas (KA-1) to (KA-7). It is a group that has been removed.

The polycyclic aliphatic hydrocarbon group is a group in which one hydrogen atom of a cycloalkane represented by the following formulas (KA-8) to (KA-22) is removed.

  Examples of the divalent alicyclic hydrocarbon group include groups in which two hydrogen atoms have been removed from the alicyclic hydrocarbon of formula (KA-1) to formula (KA-22). Examples of the group include groups in which three hydrogen atoms have been removed from the alicyclic hydrocarbons of the formulas (KA-1) to (KA-22), and examples of the tetravalent group include formulas (KA-1) to And a group obtained by removing four hydrogen atoms from the alicyclic hydrocarbon of the formula (KA-22).

  The aliphatic hydrocarbon group may have a substituent. The substituent is defined each time, and examples thereof include a halogen atom, a hydroxy group, an alkoxy group, an acyl group, an acyloxy group, an aryl group, an aralkyl group, and an aryloxy group.

Examples of alkoxy groups include methoxy group (C ₁ ), ethoxy group (C ₂ ), propoxy group (C ₃ ), butoxy group (C ₄ ), pentyloxy group (C ₅ ), hexyloxy group (C ₆ ), heptyl Examples thereof include an oxy group (C ₇ ), an octyloxy group (C ₈ ), a decyloxy group (C ₁₀ ), and a dodecyloxy group (C ₁₂ ).
Examples of the acyl group include acetyl group (C ₂ ), propionyl group (C ₃ ), butyryl group (C ₄ ), valeryl group (C ₅ ), hexanoyl group (C ₆ ), heptanoyl group (C ₇ ), octanoyl group ( Examples include those in which an alkyl group such as C ₈ ), decanoyl group (C ₁₀ ) and dodecanoyl group (C ₁₂ ) and a carbonyl group are bonded, and those in which an aryl group such as benzoyl group (C ₇ ) and a carbonyl group are bonded. It is done.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.
Examples of the aralkyl group include benzyl group (C ₇ ), phenethyl group (C ₈ ), phenylpropyl group (C ₉ ), naphthylmethyl group (C ₁₁ ), and naphthylethyl group (C ₁₂ ).
Aryloxy groups include phenyloxy group (C ₆ ), naphthyloxy group (C ₁₀ ), anthryloxy group (C ₁₄ ), biphenyloxy group (C ₁₂ ), phenanthryloxy group (C ₁₄ ) and full A combination of an aryl group such as an oleenyloxy group (C ₁₃ ) and an oxygen atom is exemplified.

The monovalent aromatic hydrocarbon group typically includes an aryl group.
Examples of the aryl group include a phenyl group (C ₆ ), a naphthyl group (C ₁₀ ), an anthryl group (C ₁₄ ), a biphenyl group (C ₁₂ ), a phenanthryl group (C ₁₄ ), and a fluorenyl group (C ₁₃ ). . Examples of the divalent aromatic hydrocarbon group include an arylene group in which one hydrogen atom is further removed from the aryl group exemplified here.

  The aromatic hydrocarbon group may also have a substituent. Although such a substituent is defined each time, a halogen atom, an alkoxy group, an acyl group, an alkyl group, and an aryloxy group can be mentioned. Among these, the alkyl group is the same as those exemplified as the chain aliphatic hydrocarbon group, and among the substituents optionally present in the aromatic hydrocarbon group, those other than the alkyl group are aliphatic hydrocarbon groups. The same thing as what was illustrated as a substituent of is included.

  The saturated hydrocarbon group means a saturated group among the above-described aliphatic hydrocarbon groups, that is, a saturated group among the above-described chain and cyclic aliphatic hydrocarbon groups. Further, the saturated hydrocarbon group may have the same substituent as the aliphatic hydrocarbon group.

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

  Hereinafter, the components of the resist composition will be described.

  As described above, the present invention relates to a salt represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”).

［式（Ｉ）中、
Ｑ^１及びＱ^２は、同一又は相異なり、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、（１＋ｍ１）価の炭素数１〜２０の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子はフッ素原子又はヒドロキシ基に置き換わっていてもよく、該飽和炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｘ^１は、ハロゲン原子を表す。
ｍ１は、２又は３を表し、複数存在するＸ^１は、それぞれ独立に、同一であっても異なっていてもよい。
Ｚ^＋は、有機カチオンを表す。］ <Salt represented by formula (I)>

[In the formula (I),
Q ¹ and Q ² are the same or different and each represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a (1 + m1) -valent saturated hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be replaced by a fluorine atom or a hydroxy group, and the saturated hydrocarbon group May be replaced with an oxygen atom or a carbonyl group.
X ¹ represents a halogen atom.
m1 represents 2 or 3, and a plurality of X ¹ may be the same or different each independently.
Z ⁺ represents an organic cation. ]

In the following description, those having a negative charge obtained by removing the organic cation (Z ⁺ ) from the salt represented by the formula (I) are sometimes referred to as “sulfonate anions”.

First, the sulfonate anion constituting the salt represented by the formula (I) will be described.
Q ¹ and Q ² are the same or different and each represents a fluorine atom or a C 1-6 perfluoroalkyl group. Examples of the perfluoroalkyl group include those in which all the hydrogen atoms contained in the alkyl group in the alkyl group having 1 to 6 carbon atoms already exemplified are replaced with fluorine atoms. Specific examples include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group. Here, the perfluoroalkyl group has been described with specific examples. However, Q ¹ and Q ² are the same or different and are preferably a fluorine atom or a trifluoromethyl group, and both Q ¹ and Q ² are further fluorine atoms. preferable.

L ¹ is a (1 + m1) valence, that is, a trivalent or tetravalent saturated hydrocarbon group having 1 to 20 carbon atoms.
The trivalent saturated hydrocarbon group for L ¹ is an alkanetriyl group exemplified above in the range of 1 to 20 carbon atoms, and any alicyclic ring of the above formula (KA-1) to formula (KA-22). And a trivalent alicyclic hydrocarbon group obtained by removing three hydrogen atoms from the formula hydrocarbon. Further, the trivalent saturated hydrocarbon group of L ¹ may be a trivalent group in which an alkanediyl group and a trivalent alicyclic hydrocarbon group are arbitrarily combined as long as it has a carbon number of 20 or less. Further, a trivalent group in which an alkanetriyl group and a divalent alicyclic hydrocarbon group are arbitrarily combined may be used.

The tetravalent saturated hydrocarbon group of L ¹ is an alkanetetrayl group already exemplified in the range of 1 to 20 carbon atoms, and any alicyclic ring of the above formula (KA-1) to formula (KA-22). And a tetravalent alicyclic hydrocarbon group obtained by removing four hydrogen atoms from the formula hydrocarbon. In addition, the tetravalent saturated hydrocarbon group of L ¹ may be a tetravalent group in which an alkanediyl group and a tetravalent alicyclic hydrocarbon group are arbitrarily combined as long as it has a carbon number of 20 or less. Further, a tetravalent group arbitrarily combining an alkanetriyl group and a trivalent alicyclic hydrocarbon group, or an arbitrary combination of an alkanetetrayl group and a divalent alicyclic hydrocarbon group 4 May be a valent group.

As described above, the methylene group constituting the saturated hydrocarbon group for L ¹ may be replaced with an oxygen atom or a carbonyl group. Thus, the salt represented by the formula (I) having a group in which the methylene group constituting the saturated hydrocarbon group is replaced by an oxygen atom or a carbonyl group as L ¹ is the salt represented by the formula (I). This is preferable in view of ease of manufacture. In addition, the manufacturing method of the salt represented by Formula (I) is mentioned later.

［式（Ｌ^１−１）中、
Ｘ^０は、置換基を有していてもよい炭素数１〜１８の（１＋ｍ１）価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子はフッ素原子又はヒドロキシ基に置き換わっていてもよく、該飽和炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｘ^１及びｍ１は上記と同じ意味を表す。
＊は、Ｃ（Ｑ^１）（Ｑ^２）の炭素原子との結合手を表す。］ When the methylene group constituting the saturated hydrocarbon group for L ¹ is a group in which an oxygen atom or a carbonyl group is substituted, a specific example of the group represented by -L ^1- (X ¹ ) _m1 is a group represented by the formula (L ¹ -1) is mentioned.

[In the formula (L ¹ -1),
X ⁰ represents an optionally substituted (1 + m1) -valent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group is replaced with a fluorine atom or a hydroxy group. The methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
X ¹ and m ¹ represent the same meaning as described above.
* Represents a bond with a carbon atom of C (Q ¹ ) (Q ² ). ]

In the formula (L ¹ -1), X ⁰ represents a (1 + m1) valence, that is, a trivalent or tetravalent saturated hydrocarbon group.
Examples of the group represented by the formula (L ¹ -1) include the following.

Here, the specific example of the sulfonate anion which comprises the salt represented by Formula (I) is shown.

Next, the organic cation (Z ⁺ ) constituting the salt represented by the formula (I) will be described.
Examples of the organic cation represented by Z ⁺ include organic onium cations, organic sulfonium cations, organic iodonium cations, organic ammonium cations, organic benzothiazolium cations, and organic phosphonium cations. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, an organic sulfonium cation and an organic iodonium cation are preferable, and more preferably, they are represented by any of the following formulas (b2-1) to (b2-4). Organic cation [hereinafter referred to as “cation (b2-1)”, “cation (b2-2)”, “cation (b2-3)” and “cation (b2-4)” according to the number of each formula There is. ].

In formula (b2-1) to formula (b2-4),
R ^{b4 to} R ^b6 each independently represent an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The aliphatic hydrocarbon group may have a hydroxy group, an alkoxy group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the alicyclic hydrocarbon group may be a halogen atom. May have an acyl group having 2 to 4 carbon atoms or a glycidyloxy group, and the aromatic hydrocarbon group is a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, or 3 carbon atoms. It may have an -18 alicyclic hydrocarbon group or an alkoxy group having 1 to 12 carbon atoms. Two ^members selected from R ^b4 , R ^b5 and R ^b6 may be combined to form a ring containing a sulfur atom.

The ring which may be formed by combining two selected from R ^b4 , R ^b5 and R ^b6 is any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated. It may be a ring and may contain one or more sulfur atoms and / or one or more oxygen atoms as long as it contains one or more sulfur atoms. As the ring, a ring having 3 to 18 carbon atoms is preferable, and a ring having 4 to 13 carbon atoms is more preferable.

R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5. When m2 is 2 or more, the plurality of R ^b7 may be the same or different from each other. When n2 is 2 or more, the plurality of R ^b8 may be the same or different from each other.
R ^b9 and R ^b10 each independently represent a C 1-18 aliphatic hydrocarbon group or a C 3-18 alicyclic hydrocarbon group.
R ^b11 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^{b9 to} R ^b11 are independently of each other an aliphatic hydrocarbon group (preferably having 1 to 12 carbon atoms) or an alicyclic hydrocarbon group (preferably having 3 to 18 carbon atoms, more preferably 4 to 12 carbon atoms). It is.
R ^b12 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 aromatic hydrocarbon group is And having an aliphatic hydrocarbon group having 1 to 12 carbon atoms, 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. Also good.
R ^b9 and R ^b10 and R ^b11 and R ^b12 may be bonded to each other to form a 3- to 12-membered (preferably 3- to 7-membered) ring, and methylene contained in the ring The group may be replaced with an oxygen atom, a sulfur atom or a carbonyl group.

R ^{b13 to} R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b11 represents an oxygen atom or a sulfur atom.
o2, p2, s2, and t2 each independently represent an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, the plurality of R ^b13 may be the same or different from each other. When p2 is 2 or more, the plurality of R ^b14 may be the same or different from each other, and s2 is When it is 2 or more, the plurality of R ^b15 may be the same or different from each other, and when t2 is 2 or more, the plurality of R ^b18 may be the same or different from each other.

An alkyl group is mentioned as an aliphatic hydrocarbon group.
Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of the acyl group include acetyl, propionyl, butyryl and the like.
Examples of the alkylcarbonyloxy group include methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group. Group, pentylcarbonyloxy group, hexylcarbonyloxy group, octylcarbonyloxy group, 2-ethylhexylcarbonyloxy group and the like.

^Among the aliphatic hydrocarbon groups of R ^{b9 to} R ^b12 , preferred groups are 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.
Among the alicyclic hydrocarbon groups represented by R ^{b9 to} R ^b11 , preferred groups are a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclodecyl group, a 2-alkyladamantan-2-yl group, 1- (Adamantan-1-yl) alkane-1-yl group and isobornyl group.
^Among the aromatic hydrocarbon groups ^represented by R ^b12 , preferred groups are a phenyl group, a 4-methylphenyl group, a 4-ethylphenyl group, a 4-tert-butylphenyl group, a 4-cyclohexylphenyl group, and a 4-methoxyphenyl group. A biphenylyl group and a naphthyl group.
The aromatic hydrocarbon group having an aliphatic hydrocarbon group represented by R ^b12 is typically an aralkyl group, and specific examples include a benzyl group.
Examples of the ring formed by combining R ^b9 and R ^b10 include a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring. Is mentioned.
Examples of the ring formed by combining R ^b11 and R ^b12 include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

式（ｂ２−１−１）中、
Ｒ^b19、Ｒ^b20及びＲ^b21は、互いに独立に、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１８の脂肪族炭化水素基、炭素数３〜１８の脂環式炭化水素基又は炭素数１〜１２のアルコキシ基を表し、Ｒ^b19、Ｒ^b20及びＲ^b21から選ばれる２つが一緒になって単結合、−Ｏ−又は炭素数１〜４の２価の脂肪族炭化水素基を表し、イオウ原子を含む環を形成してもよい。 Among the above-mentioned organic cations, the cation (b2-1) is preferable, and an organic cation represented by the following formula (b2-1-1) [hereinafter referred to as “cation (b2-1-1)” may be used. ], More preferably a triphenylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 0) or a tolylsulfonium cation (in formula (b2-1-1), v2 = w2 = X2 = 1, and R ^b19 , R ^b20 and R ^b21 are all methyl groups).

In formula (b2-1-1),
R ^b19 , R ^b20 and R ^b21 each independently represent a halogen atom (more preferably a fluorine atom), a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, or an alicyclic hydrocarbon having 3 to 18 carbon atoms. ^Represents a group or an alkoxy group having 1 to 12 carbon atoms, and two selected from R ^b19 , R ^b20 and R ^b21 are combined to form a single bond, —O— or a divalent aliphatic hydrocarbon having 1 to 4 carbon atoms. Represents a group and may form a ring containing a sulfur atom.

The aliphatic hydrocarbon group is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, and as a substituent, a hydroxy group, an alkoxy group having 1 to 12 carbon atoms or a carbon number. It may have 6-18 aromatic hydrocarbon groups.
The alicyclic hydrocarbon group preferably has 4 to 18 carbon atoms, and may have a halogen atom, an acyl group having 2 to 4 carbon atoms or a glycidyloxy group as a substituent.
v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).
When v2 is 2 or more, a plurality of R ^b19 may be the same or different, and when w2 is 2 or more, a plurality of R ^b20 may be the same or different. When x2 is 2 or more, a plurality of R ^{b19 b21} may be the same as or different from each other.
Among these, R ^b19 , R ^b20 and R ^b21 are preferably independently of each other preferably 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. It is.

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

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

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

As described above, the salt represented by the formula (I) has been described by dividing it into the sulfonate anion and the organic cation constituting the salt. The salt represented by the formula (I) is a combination of the sulfonate anion and the organic cation. It is. These sulfonate anions and organic cations can be arbitrarily combined.
Specific examples of this combination include those listed in Tables 1 to 6.

Tables 1 to 6 show more preferable salts represented by the formula (I) among the salts represented by the formula (I) represented by the combination of the sulfonate anion and the organic cation. It is as follows.

  Since the salt represented by the formula (I) has a highly reactive halogen atom at the terminal, it is also useful as a raw material for producing various functional materials.

Subsequently, a salt represented by the formula (I) when the group represented by -L ^1- (X ¹ ) _m1 is a group represented by the following [referred to as a salt represented by the formula (I1). ] As an example, one embodiment of the method for producing the salt represented by the formula (I) will be described. (In the formula, all symbols have the same meaning as described above.)

この反応の溶媒としては、クロロホルム、アセトニトリルなどが用いられる。式（Ｉ１−ａ）で表される化合物は、例えば、特開２００６−２５７０７８号公報に記載された方法で製造することができる。 First, the salt represented by the formula (I1-c) is obtained by reacting the salt represented by the formula (I1-a) with the compound represented by the formula (I1-b) in a solvent. be able to.

As a solvent for this reaction, chloroform, acetonitrile or the like is used. The compound represented by the formula (I1-a) can be produced, for example, by the method described in JP-A-2006-257078.

この反応の溶媒としては、クロロホルム、アセトニトリルなどが用いられる。
式（Ｉ１−ｄ）で表される化合物としては、例えば、以下で表される化合物などが挙げられる。

The salt represented by the formula (I1) can be produced by reacting the salt represented by the formula (I1-c) with the compound represented by the formula (I1-d) in a solvent. .

As a solvent for this reaction, chloroform, acetonitrile or the like is used.
Examples of the compound represented by the formula (I1-d) include compounds represented by the following.

In addition, a salt represented by the formula (I) when the group represented by -L ^1- (X ¹ ) _m1 is a group represented by the following [referred to as a salt represented by the formula (I2). ] As an example, one embodiment of the method for producing the salt represented by the formula (I) will be described. (In the formula, all symbols have the same meaning as described above.)

この反応の溶媒としては、クロロホルム、アセトニトリルなどが用いられる。
式（Ｉ２−ｄ）で表される化合物としては、例えば、以下で表される化合物などが挙げられる。

The salt represented by the formula (I2) can be produced by reacting the salt represented by the formula (I1-c) with the compound represented by the formula (I2-d) in a solvent. .

As a solvent for this reaction, chloroform, acetonitrile or the like is used.
Examples of the compound represented by the formula (I2-d) include compounds represented by the following.

Further, a salt represented by the formula (I) when the group represented by -L ^1- (X ¹ ) _m1 is a group represented by the following [referred to as a salt represented by the formula (I3). ] As an example, one embodiment of the method for producing the salt represented by the formula (I) will be described. (In the formula, all symbols have the same meaning as described above.)

By reacting the salt represented by the formula (I1-c) with the compound represented by the formula (I3-a), the salt represented by the formula (I3-b) can be produced.
Examples of the solvent include acetonitrile.

The salt represented by the formula (I3-c) can be produced by treating the salt represented by the formula (I3-b) with an acid in a solvent.
Examples of the solvent include chloroform and methanol.
Examples of the acid include hydrochloric acid.

The salt represented by the formula (I3-d) can be obtained by reacting the salt represented by the formula (I3-c) with the compound represented by the formula (I1-b).

A salt represented by the formula (I3) can be produced by reacting a salt represented by the formula (I3-d) with a compound represented by the formula (I1-d).
Examples of the solvent include acetonitrile.

In addition, a salt represented by the formula (I) when the group represented by -L ^1- (X ¹ ) _m1 is a group represented by the following [referred to as a salt represented by the formula (I4). ] As an example, one embodiment of the method for producing the salt represented by the formula (I) will be described. (In the formula, all symbols have the same meaning as described above.)

A salt represented by the formula (I4) can be produced by reacting a salt represented by the formula (I3-d) with a compound represented by the formula (I2-d).
Examples of the solvent include acetonitrile.

  The acid generator of the present invention contains a salt (I). The acid generator of the present invention may contain one or more salts (I). Further, the acid generator of the present invention is a salt known as an acid generator other than the salt (I) (for example, an organic cation contained in the salt (I) and a known anion (salt (I)). And a sulfonate anion contained in the salt (I) and a known cation (a salt comprising a cation other than the organic cation contained in the salt (I), etc.). . Hereinafter, salts other than the salt (I) contained in the acid generator of the present invention may be referred to as “acid generator (B)”.

  Examples of the acid generator (B) preferably include salts represented by the formulas (B1-1) to (B1-26), and more preferably a salt containing a triarylsulfonium cation, that is, a formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), Formula (B1-11), Formula (B1-12), Formula (B1-13), Formula ( B1-14), Formula (B1-18), Formula (B1-19), Formula (B1-20), Formula (B1-21), Formula (B1-22), Formula (B1-23), Formula (B1) -24), a salt represented by formula (B1-25) or formula (B1-26).

The total amount of the acid generator of the present invention may be salt (I).
When the acid generator of the present invention contains the salt (I) and the acid generator (B), the content of the salt (I) is preferably 10 masses with respect to 100 parts by mass of the total amount of the acid generator of the present invention. Part or more (more preferably 30 parts by weight or more), preferably 90 parts by weight or less (more preferably 70 parts by weight or less).

Next, the resist composition of the present invention will be described. The resist composition of the present invention comprises the acid generator of the present invention and a resin, and the resin has an acid-labile group and is a resin that is insoluble or hardly soluble in an alkaline aqueous solution. It is a resin (hereinafter referred to as “resin (A)”) that can be dissolved in an alkaline aqueous solution by action.
The content of the acid generator of the present invention is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 30 parts by mass or less (more preferably 25 parts by mass) with respect to 100 parts by mass of the resin (A). Part or less).

<Resin (A)>
As described above, the resin (A) is insoluble or hardly soluble in an alkaline aqueous solution and has a characteristic that it becomes soluble in an alkaline aqueous solution by the action of an acid (hereinafter, sometimes referred to as “acidic action characteristic”). Note that “can be dissolved in an alkaline aqueous solution by the action of an acid” means “insoluble or hardly soluble in an alkaline aqueous solution before contact with an acid, but soluble in an alkaline aqueous solution after contact with an acid”. Means.

  The resin (A) having acid action characteristics has an acid labile group (hereinafter, sometimes referred to as “acid labile group”) in its molecule. Such a resin (A) is a monomer having an acid labile group (hereinafter, this monomer is sometimes referred to as “monomer (a1)”, and the structural unit derived from the monomer (a1) is referred to as “structural unit (a1)”. Can be produced by polymerization. In producing the resin (A) having acid action characteristics, the monomer (a1) may be used alone, or two or more kinds may be used in combination.

［式（１）中、
Ｒ^a1、Ｒ^ａ２及びＲ^a3（Ｒ^a1〜Ｒ^a3）は、それぞれ独立に、炭素数１〜８のアルキル基、炭素数３〜２０の脂環式炭化水素基又はこれらを組み合わせた基を表すか、Ｒ^a1及びＲ^a2は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。＊は結合手を表す。］ <Acid labile group>
The “acid labile group” means a group that cleaves a leaving group upon contact with an acid to form a hydrophilic group (for example, a hydroxy group or a carboxy group). Examples of the acid labile group include a group represented by the formula (1) (acid labile group (1)) and a group represented by the formula (2) (acid labile group (2)). .

[In Formula (1),
R ^a1 , R ^a2 and R ^a3 (R ^{a1 to} R ^a3 ) each independently represent 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. ]

［式（２）中、
Ｒ^a1’及びＲ^a2’は、それぞれ独立に、水素原子又は炭素数１〜１２の１価の炭化水素基を表し、Ｒ^a3’は、炭素数１〜２０の炭化水素基を表すか、Ｒ^a2’及びＲ^a3’は互いに結合して炭素数２〜２０の２価の複素環基を形成する。該１価の炭化水素基及び該２価の複素環基を構成するメチレン基は、酸素原子又は硫黄原子に置き換わってもよい。＊は結合手を表す。］

[In Formula (2),
R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms, or R ^{a3 ′ a2 ′} and R ^{a3 ′} combine with each other to form a divalent heterocyclic group having 2 to 20 carbon atoms. The monovalent hydrocarbon group and the methylene group constituting the divalent heterocyclic group may be replaced with an oxygen atom or a sulfur atom. * Represents a bond. ]

The alkyl groups and alicyclic hydrocarbon groups represented by R ^{a1 to} R ^a3 of the acid labile group (1) include those already exemplified in each carbon number range. However, carbon number of this alicyclic hydrocarbon group becomes like this. Preferably it is the range of 3-16.

When R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group, the group represented by —C (R ^a1 ) (R ^a2 ) (R ^a3 ) is any of the following groups: This is the case. The carbon number of the divalent hydrocarbon group is preferably in the range of 3-12.

Examples of the acid labile group (1) include a 1,1-dialkylalkoxycarbonyl group (in the formula (1), groups in which R ^{a1 to} R ^a3 are alkyl groups, preferably tert-butyl groups), 2-alkyl An adamantane-2-yloxycarbonyl group (in formula (1), R ^a1 and R ^a2 combine to form an adamantyl ring, and R ^a3 is an alkyl group) and 1- (adamantan-1-yl ) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

Examples of the R ^{a1 ′} and R ^{a2 ′} hydrocarbon groups of the acid labile group (2) include an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Among these groups, the same groups are included in the range having 20 or less carbon atoms. However, at least one of R ^{a1 ′} and R ^{a2 ′} is preferably a hydrogen atom.

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

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

  Among them, the monomer (a1) having an acid labile group (1) and / or an acid labile group (2) is preferable, and having an acid labile group (1) and / or an acid labile group (2). A (meth) acrylic monomer is more preferable.

  Of the (meth) acrylic monomers having an acid labile group, the monomer (a1) having an alicyclic hydrocarbon group having 5 to 20 carbon atoms is preferred. Since the resin (A) obtained using such a monomer (a1) has a bulky structure such as an alicyclic hydrocarbon group, the resist composition containing the resin (A) The resolution tends to be better.

［式（ａ１−１）中、
Ｌ^a1は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−（ｋ１は１〜７の整数を表し、＊はカルボニル基との結合手を表す。）で表される基を表す。
Ｒ^a4は、水素原子又はメチル基を表す。
Ｒ^a6は、炭素数１〜１０の脂肪族炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
式（ａ１−２）中、
Ｌ^a2は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−（ｋ１は前記と同義である。）で表される基を表す。
Ｒ^a5は、水素原子又はメチル基を表す。
Ｒ^a7は、炭素数１〜１０の脂肪族炭化水素基を表す。
ｎ１は０〜１０の整数を表す。
ｎ１’は０〜３の整数を表す。］ <Preferred structural unit (a1)>
The resin (A) having a suitable structural unit (a1) obtained by using the monomer (a1) having such an alicyclic hydrocarbon group will be further described in detail. Among the resins (A), a structural unit represented by the formula (a1-1) (hereinafter sometimes referred to as “structural unit (a1-1)”) or a structural unit represented by the formula (a1-2) A resin (A) having (hereinafter referred to as “structural unit (a1-2)” in some cases) is preferable. Such resin (A) may have the structural unit (a1-1) as a single species, may have a plurality of types, or may have the structural unit (a1-2) as a single species. In addition, a plurality of types may be included, and the structural unit (a1-1) and the structural unit (a1-2) may be combined.

[In the formula (a1-1),
L ^a1 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k1 —CO—O— (k1 represents an integer of 1 to 7, and * represents a bond to a carbonyl group). Represent.
R ^a4 represents a hydrogen atom or a methyl group.
R ^a6 represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.
m1 represents the integer of 0-14.
In formula (a1-2),
L ^a2 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k1 —CO—O— (k1 is as defined above).
R ^a5 represents a hydrogen atom or a methyl group.
R ^a7 represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.
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—, and L ^a1 and L ^a2 are preferably oxygen atoms or k1 is 1 to 4 A group represented by * —O— (CH ₂ ) _k1 —CO—O—, more preferably an oxygen atom or * —O—CH ₂ —CO—O—, still more preferably oxygen. Is an atom.
R ^a4 and R ^a5 are preferably methyl groups.
Of the aliphatic hydrocarbon groups of R ^a6 and R ^a7 , preferably an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms, and within the range of the upper limit of the carbon number, Includes the same as those already exemplified. The aliphatic hydrocarbon groups for R ^a6 and R ^a7 are each independently preferably an alkyl group having 8 or less carbon atoms or an alicyclic hydrocarbon group having 8 or less carbon atoms, more preferably an alkyl group having 6 or less carbon atoms. Or it is an alicyclic hydrocarbon group having 6 or less carbon atoms.
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 the structural unit (a1-1), structural units represented by any of the following formulas (a1-1-1) to (a1-1-8) are preferable, and the structural units (a1-1-1) to (a1-1-1) The structural unit represented by any one of (a1-1-4) is more preferable.

  Examples of the monomer (a1) from which these structural units (a1-1) can be derived include those described in JP-A No. 2010-204646.

On the other hand, as the structural unit (a1-2), those represented by any of the following formulas (a1-2-1) to (a1-2-12) are preferable. Among these, the structural unit represented by any of formula (a1-2-3), formula (a1-2-4), formula (a1-2-9), and formula (a1-2-10) is More preferred is a structural unit represented by formula (a1-2-3) or formula (a1-2-9).

  Examples of the monomer (a1) capable of deriving the structural unit (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, and 1-ethyl. Examples include cycloheptan-1-yl (meth) acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, and 1-isopropylcyclopentan-1-yl (meth) acrylate.

  When the resin (A) has the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is based on the total structural unit (100 mol%) of the resin (A). The range of 10 to 95 mol% is preferable, the range of 15 to 90 mol% is more preferable, the range of 20 to 85 mol% is more preferable, and the range of 20 to 60 mol% is particularly preferable. When the structural unit (a1) has a structural unit (a1) having an adamantyl group (particularly preferably, the structural unit (a1-1)), the total of the structural units (a1) in the resin (A) The structural unit (a1) having an adamantyl group is preferably 15 mol% or more with respect to (100 mol%). With such a content ratio, the resin (A) having the structural unit (a1) having an adamantyl group tends to have good dry etching resistance of a resist pattern produced from the resist composition containing the resin (A). There is. In addition, in order to make the total content rate of a structural unit (a1-1) and / or a structural unit (a1-2) into the above-mentioned range, when manufacturing resin (A), it is with respect to the usage-amount of all monomers. What is necessary is just to adjust the usage-amount of the monomer which induces | guides | derives a structural unit (a1-1) and / or a structural unit (a1-2).

  Among the structural units of the resin (A), the structural unit (a1-1) and the structural unit (a1-2) that are preferable for the resin (A) to have acid action characteristics are described in detail. It is particularly preferable that the resin (A) has the unit (a1-1).

  The resin (A) may have a structural unit (a1) other than the structural unit (a1-1) and the structural unit (a1-2) which are suitable structural units (a1). Hereinafter, the structural unit (a1) other than the structural unit (a1-1) and the structural unit (a1-2) will be described by showing a monomer (a1) that derives the structural unit (a1).

［式（ａ１−３）中、
Ｒ^a9は、水素原子、置換基（例えばヒドロキシ基）を有していてもよい炭素数１〜３の脂肪族炭化水素基、カルボキシ基、シアノ基、又は−ＣＯＯＲ^a13で表される基を表し、Ｒ^a13は、炭素数１〜８の脂肪族炭化水素基を表し、該脂肪族炭化水素基に含まれる水素原子はヒドロキシ基などで置換されていてもよく、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。Ｒ^a10、Ｒ^a11及びＲ^a12は、それぞれ独立に、炭素数１〜１２の脂肪族炭化水素基を表すか、或いはＲ^a10及びＲ^a11は互いに結合して環を形成している。該脂肪族炭化水素基及に含まれる水素原子はヒドロキシ基などで置換されていてもよく、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。］ The resin (A) may have a structural unit (a1) derived from a monomer represented by the following formula (a1-3) (hereinafter sometimes referred to as “monomer (a1-3)”). . Since the resin (A) having the structural unit (a1) derived from the monomer (a1-3) contains a rigid norbornane ring in its main chain, the present resist containing such a resin (A) The composition tends to produce a resist pattern having excellent dry etching resistance.

[In the formula (a1-3),
R ^a9 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have a substituent (for example, a hydroxy group), a carboxy group, a cyano group, or a group represented by —COOR ^a13. , R ^a13 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, and a hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with a hydroxy group or the like, and constitutes the aliphatic hydrocarbon group The methylene group may be replaced by an oxygen atom or a carbonyl group. R ^a10 , R ^a11 and R ^a12 each independently represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or R ^a10 and R ^a11 are bonded to each other to form a ring. The hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with a hydroxy group or the like, and the methylene group constituting the aliphatic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. ]

The aliphatic hydrocarbon group which may have a substituent of R ^a9 is typically an alkyl group which may have a substituent, and among these alkyl groups, an alkyl having no substituent The group includes those already exemplified in the range of 1 to 8 carbon atoms. Examples of the substituent, particularly the aliphatic hydrocarbon group (alkyl group) having a hydroxy group include a hydroxymethyl group and a 2-hydroxyethyl group. ^Examples of R ^a13 include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group, and a 2-oxo-oxolan-4-yl group.

The aliphatic hydrocarbon groups of R ^{a10 to} R ^a12 are also typically alkyl groups, and specific examples thereof are the same as those of R ^a9 . The ring formed by combining R ^a10 and R ^a11 together with the carbon atom to which they are bonded includes a cyclohexane ring and an adamantane ring.

As a monomer (a1-3), what was described in Unexamined-Japanese-Patent No. 2010-204646 is used, for example. Among these, a monomer represented by any one of the following formulas (a1-3-1) to (a1-3-4) is preferable, and the formula (a1-3-2) or (a1-3-4) Is more preferable, and a monomer represented by formula (a1-3-2) is more preferable.

  When the resin (A) has a structural unit derived from the monomer (a1-3), the content is preferably in the range of 10 to 95 mol% with respect to the total structural unit of the resin (A). The range of 90 mol% is more preferable, and the range of 20 to 85 mol% is more preferable.

［式（ａ１−４）中、
Ｒ¹⁰は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
ｌ^ａは０〜４の整数を表す。
Ｒ¹¹は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイル基又はメタクリロイル基を表し、ｌ^ａが２以上である場合、複数のＲ¹¹は互いに同一であっても異なってもよい。
Ｒ¹²及びＲ¹³はそれぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表す。
Ｘ^a2は、置換基を有していてもよい炭素数１〜１７の脂肪族炭化水素基又は単結合を表し、該脂肪族炭化水素基を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基、スルホニル基又は−Ｎ（Ｒ^ｃ）−（ただし、Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す）で表される基に置き換わっていてもよい。
Ｙ^a3は、置換基を有していてもよい炭素数１〜１８の炭化水素基を表す。］ The resin (A) may have a structural unit (a1) derived from a monomer represented by the following formula (a1-4) (hereinafter sometimes referred to as “monomer (a1-4)”).

[In the formula (a1-4),
R ¹⁰ represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
l ^a represents an integer of 0 to 4;
R ¹¹ is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyl group, or methacryloyl. In the case where l ^a is 2 or more, a plurality of R ¹¹ may be the same as or different from each other.
R ¹² and R ¹³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.
X ^a2 represents an ^optionally substituted aliphatic hydrocarbon group having 1 to 17 carbon atoms or a single bond, and the methylene group constituting the aliphatic hydrocarbon group includes an oxygen atom, a sulfur atom, a carbonyl A group, a sulfonyl group, or a group represented by —N (R ^c ) — (wherein R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) may be substituted.
Y ^a3 represents an ^optionally substituted hydrocarbon group having 1 to 18 carbon atoms. ]

Among “an alkyl group having 1 to 6 carbon atoms which may have a halogen atom”, the alkyl group includes those already exemplified in the range of 1 to 6 carbon atoms. As the alkyl group having a halogen atom, an alkyl group having a fluorine atom is preferable. For example, a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert- Examples thereof include a butyl group, a perfluoropentyl group, and a perfluorohexyl group. Among these, as R < ¹⁰ >, a hydrogen atom and a C1-C4 alkyl group are preferable, a hydrogen atom, a methyl group, and an ethyl group are more preferable, and a hydrogen atom and a methyl group are especially preferable.
The alkoxy group of R ¹¹ includes those already exemplified in the range of 1 to 6 carbon atoms. Among them, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group and an ethoxy group are more preferable, and a methoxy group is particularly preferable. preferable.
The acyl group and acyloxy group of R ¹¹ include those already exemplified in the range of 2 to 4 carbon atoms.
The hydrocarbon groups of R ¹² and R ¹³ are those having 1 to 12 carbon atoms, and the hydrocarbon group of Y ^a3 is the aliphatic hydrocarbon group exemplified above in the range of 1 to 18 carbon atoms. Contains any of the aromatic hydrocarbon groups.
The aliphatic hydrocarbon group of X ^a2 is a divalent chain hydrocarbon group, a divalent alicyclic hydrocarbon group, or a divalent group in which a chain hydrocarbon group and an alicyclic hydrocarbon group are combined. And groups obtained by appropriately combining the groups already exemplified in the range of 1 to 17 carbon atoms.

As a monomer (a1-4), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among them, any monomer represented by any of the following formulas (a1-4-1) to (a1-4-7) is preferable, and the formulas (a1-4-1) to (a1-4-) The monomer represented by any one of 5) is more preferable.

  When the resin (A) has a structural unit derived from the monomer (a1-4), the content is preferably in the range of 10 to 95 mol% with respect to the total structural unit of the resin (A). The range of mol% is more preferable, and the range of 20 to 85 mol% is particularly preferable.

式（ａ１−５）中、
Ｒ^３１は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｌ^１〜Ｌ^３は、オキシ基、チオキシ基又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−で表される基を表す。ここで、ｋ１は１〜７の整数を表し、＊はカルボニル基（−ＣＯ−）との結合手である。
Ｚ^１は、単結合又は炭素数１〜６のアルカンジイル基であり、該アルカンジイル基中に含まれるメチレン基は、オキシ基又はカルボニル基に置き換わっていてもよい。
ｓ１及びｓ１’は、それぞれ独立して、０〜４の整数を表す。 As the other monomer (a1), for example, a monomer represented by the formula (a1-5) which is a (meth) acrylic monomer having an acid labile group (2) (hereinafter referred to as “monomer (a1-5)”) May be used).

In formula (a1-5),
R ³¹ represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^{1 to} L ³ represent a group represented by an oxy group, a thioxy group, or ^* —O— (CH ₂ ) _k1 —CO—O—. Here, k1 represents an integer of 1 to 7, and * is a bond with a carbonyl group (—CO—).
Z ¹ is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the methylene group contained in the alkanediyl group may be replaced with an oxy group or a carbonyl group.
s1 and s1 ′ each independently represents an integer of 0 to 4.

In formula (a1-5), R ³¹ is preferably a hydrogen atom, a methyl group, or a trifluoromethyl group.
L ¹ is preferably an oxygen atom.
One of L ² and L ³ 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 ¹ 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 ratio is in the range of 1 to 95 mol% with respect to all the structural units (100 mol%) of the resin (A). Is preferable, the range of 3-90 mol% is more preferable, and the range of 5-85 mol% is further more preferable.

<Acid stable structural unit>
Resin (A) is a structural unit having no acid labile group in addition to the structural unit (a1) containing an acid labile group (hereinafter referred to as “acid stable structural unit” in some cases). Preferably, the derivatizable monomer is referred to as an “acid-stable monomer”. In the resin (A), the acid stable structural unit may have only one type or may have a plurality of types.

  When the resin (A) has an acid stable structural unit, the content ratio of the acid stable structural unit may be determined based on the content ratio of the structural unit (a1). The ratio of the content ratio of the structural unit (a1) and the content ratio of the acid-stable structural unit is represented by [structural unit (a1)] / [acid-stable structural unit], and preferably 10 to 80 mol% / 90 to It is 20 mol%, More preferably, it is 20-60 mol% / 80-40 mol%. If it does in this way, there exists a tendency for the dry etching tolerance of the resist pattern obtained from this resist composition containing resin (A) to become still better.

Next, a preferable thing is demonstrated among an acid stable structural unit.
The acid stable structural unit is preferably a structural unit having a hydroxy group or a lactone ring. An acid stable structural unit having a hydroxy group (hereinafter sometimes referred to as “acid stable structural unit (a2)”) and / or an acid stable structural unit having a lactone ring (hereinafter sometimes referred to as “acid stable structural unit (a3)”) When the resist composition containing the resin (A) is applied to a substrate, a coating film formed on the substrate or a composition layer obtained from the coating film is a substrate. The resist composition can easily produce a resist pattern with good resolution. In addition, the manufacturing method of the resist pattern using this resist composition here is mentioned later. First, the acid stable structural unit (a2) and the acid stable structural unit (a3) suitable as the acid stable structural unit will be described with specific examples.

<Acid stable structural unit (a2)>
When the acid-stable structural unit (a2) is introduced into the resin (A), a suitable acid-stable structure is used depending on the type of exposure source when producing a resist pattern from the resist composition containing the resin (A). The unit (a2) can be selected. That is, when this resist composition is used for exposure using a KrF excimer laser (wavelength: 248 nm) as an exposure source, or exposure using a high energy beam such as an electron beam or EUV light as an exposure source, an acid stable structural unit ( As a2), it is preferable to introduce an acid stable structural unit (a2-0) having a phenolic hydroxy group into the resin (A). When using exposure using a short wavelength ArF excimer laser (wavelength: 193 nm) as an exposure source, an acid stable structural unit represented by the formula (a2-1) described later is used as a resin ( It is preferable to introduce into A). Thus, each of the acid stable structural units (a2) possessed by the resin (A) can be selected according to the exposure source used for producing the resist pattern, but the acid stable structural units possessed by the resin (A) ( a2) may have only one type of acid stable structural unit (a2) suitable for the type of exposure source, and two or more types of acid stable structural unit (a2) suitable for the type of exposure source. Or an acid stable structural unit (a2) suitable for the type of exposure source and a combination of other acid stable structural units (a2).

式（ａ２−１）中、
Ｌ^a3は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k2−ＣＯ−Ｏ−（ｋ２は１〜７の整数を表し、＊はカルボニル基（−ＣＯ−）との結合手を表す。）で表される基を表す。
Ｒ^a14は、水素原子又はメチル基を表す。
Ｒ^a15及びＲ^a16は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０〜１０の整数を表す。 One specific example of the acid stable structural unit (a2) is one represented by the following formula (a2-1) (hereinafter sometimes referred to as “acid stable structural unit (a2-1)”).

In formula (a2-1),
L ^a3 is an oxygen atom or ^* —O— (CH ₂ ) _k2 —CO—O— (k2 represents an integer of 1 to 7, and * represents a bond to a carbonyl group (—CO—)). Represents the group represented.
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.

L ^a3 is preferably an oxygen atom or a group represented by —O— (CH ₂ ) _k2 —CO—O—, wherein k2 is an integer of 1 to 4, more preferably an oxygen atom or — O—CH ₂ —CO—O—, more preferably an oxygen atom.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

As an acid stable structural unit (a2-1), the following are mentioned, for example.

  As described above, the exemplified acid stable structural unit (a2-1) is derived from, for example, an acid stable monomer described in JP 2010-204646 A. Among these, the acid stable structural unit represented by any one of formula (a2-1-1) to formula (a2-1-6) is more preferable, and the formula (a2-1-1) or (a2-1-1-) The acid stable structural unit represented by 3) is more preferable.

  When the resin (A) has an acid stable structural unit (a2-1), the content ratio is preferably in the range of 1 to 45 mol%, and 1 to 40 mol% with respect to all the structural units of the resin (A). The range of 2 to 35 mol% is more preferable.

式（ａ２−０）中、
Ｒ^a30は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｒ^a31は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイル基又はメタクリロイル基を表す。
ｍａは０〜４の整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31は同一でも異なっていてもよい。 Next, the acid stable structural unit which has a phenolic hydroxy group among the acid stable structural units which have a hydroxy group is demonstrated. The acid stable structural unit is preferably one represented by the following formula (a2-0) (hereinafter sometimes referred to as “acid stable structural unit (a2-0)”).

In formula (a2-0),
R ^a30 represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
R ^a31 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyl group, or methacryloyl. Represents a group.
ma represents an integer of 0 to 4. When ma is an integer of 2 or more, the plurality of R ^a31 may be the same or different.

Specific examples of the “alkyl group having 1 to 6 carbon atoms” in the “alkyl group having 1 to 6 carbon atoms which may have a halogen atom” for R ^a30 include those already exemplified in this range. . The “C 1-6 alkyl group having a halogen atom” is one in which at least a part of the hydrogen atoms contained in the C 1-6 alkyl group is substituted with a halogen atom. The specific example of the halogen atom is as already described. Among these, R ^a30 is preferably a hydrogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group and an ethyl group, and particularly preferably a hydrogen atom and a methyl group.
Specific examples of the alkoxy group of R ^a31 include those already exemplified in the range of 1 to 6 carbon atoms. Among these, R ^a31 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group and an ethoxy group, and particularly preferably a methoxy group.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.

Among the acid stable structural units (a2-0), those represented by any of the following formulas (a2-0-1) to (a2-0-4) are preferable. An acid stable monomer capable of deriving such a structural unit is described in, for example, JP 2010-204634 A.

  Acid-stable monomer capable of deriving acid-stable structural unit (a2-0) such as p-hydroxystyrene and p-hydroxy-α-methylstyrene [hereinafter referred to as “acid-stable monomer (a2)” in some cases. ] For the production of the resin (A), an acid stable structural unit represented by the formula (a2-0-1) or the formula (a2-0-2) can be introduced into the resin (A). Is protected with a protecting group such as an acetyl group to form a protected acid stable monomer (a2), and then this protected acid stable monomer (a2) is protected. The resin (A) can also be produced using A resin (A) having an acid-stable structural unit (a2-0) can be produced by deprotecting a resin having a structural unit derived from the protected acid-stable monomer (a2) and removing the protecting group. . However, when carrying out the deprotection treatment, it is necessary to carry out the deprotection treatment without significantly damaging the other structural unit (a1).

  When the resin (A) has an acid stable structural unit (a2-0), the content is preferably in the range of 5 to 90 mol%, and preferably 10 to 85 mol% with respect to all the structural units of the resin (A). Is more preferable, and the range of 15 to 80 mol% is more preferable.

<Acid stable structural unit (a3)>
The lactone ring possessed by the acid stable structural unit (a3) may be monocyclic such as β-propiolactone ring, γ-butyrolactone ring and δ-valerolactone ring, monocyclic lactone ring and other rings. Or a condensed ring. Among these lactone rings, a γ-butyrolactone ring and a condensed ring of a γ-butyrolactone ring and another ring are preferable.

［式（ａ３−１）中、
Ｌ^a4は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
ｐ１は０〜５の整数を表す。
Ｒ^a21は炭素数１〜４の脂肪族炭化水素基を表し、ｐ１が２以上の場合、複数のＲ^a21は同一でも異なっていてもよい。
式（ａ３−２）中、
Ｌ^a5は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
ｑ１は、０〜３の整数を表す。
Ｒ^a22は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、ｑ１が２以上の場合、複数のＲ^a22は同一でも異なっていてもよい。
式（ａ３−３）中、
Ｌ^a6は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
ｒ１は、０〜３の整数を表す。
Ｒ^a23は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、ｒ１が２以上の場合、複数のＲ^a23は同一でも異なっていてもよい。］ The acid stable structural unit (a3) is preferably one represented by the following formula (a3-1), formula (a3-2) or formula (a3-3). Resin (A) may have only 1 type among these, and may have 2 or more types. In the following description, what is represented by the formula (a3-1) is referred to as “acid-stable structural unit (a3-1)”, and what is represented by the formula (a3-2) is “acid-stable structural unit ( a3-2) ”, and the compound represented by formula (a3-3) is referred to as“ acid-stable structural unit (a3-3) ”.

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

In formula (a3-1) to formula (a3-3), L ^{a4 to} L ^a6 are the same as those described for L ^a3 in formula (a2-1).
L ^{a4 to} L ^a6 are each independently an oxygen atom or a group represented by * —O— (CH ₂ ) _k3 —CO—O— in which k3 is an integer of 1 to 4, preferably an oxygen atom and * —O—CH ₂ —CO—O— is more preferable, and an oxygen atom is more preferable.
R ^{a18 to} 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 preferably integers of 0 to 2, more preferably 0 or 1. When p1 is 2, two R ^a21 may be the same as or different from each other. When q1 is 2, two R ^a22 may be the same as or different from each other, and r1 is 2. Two R ^a23 may be the same or different from each other.

  Hereinafter, preferred examples of the acid stable structural unit (a3-1), the acid stable structural unit (a3-2), and the acid stable structural unit (a3-3) will be shown.

Preferable examples of the acid stable structural unit (a3-1) are those represented by any of the following formulas (a3-1-1) to (a3-1-4).

Preferable examples of the acid stable structural unit (a3-2) are those represented by any of the following formulas (a3-2-1) to (a3-2-4).

Preferable examples of the acid stable structural unit (a3-3) are those represented by any of the following formulas (a3-3-1) to (a3-3-4).

  The acid stable structural unit (a3-1), the acid stable structural unit (a3-2), and the acid stable structural unit (a3-3) can be derived from an acid stable monomer described in JP 2010-204646 A. Among the specific examples of the acid stable structural unit (a3), the formula (a3-1-1), the formula (a3-1-2), the formula (a3-2-3), and the formula (a3-2-4) The acid stable structural unit represented by any of these is more preferable, and the acid stable structural unit represented by Formula (a3-1-1) or Formula (a3-2-3) is more preferable.

  When the resin (A) has an acid stable structural unit (a3), the content is preferably in the range of 5 to 70 mol%, and preferably 10 to 65 mol% with respect to all the structural units of the resin (A). Is more preferable, and the range of 10 to 60 mol% is more preferable.

<Other acid stable structural units>
The preferred acid stable structural unit (a2) and acid stable structural unit (a3) have been described as the acid stable structural unit possessed by the resin (A). However, the resin (A) contains the acid stable structural unit (a2) and the acid stable structural unit. It may have an acid stable structural unit other than the structural unit (a3). Here, the acid stable structural unit (a4) other than the acid stable structural unit (a2) and the acid stable structural unit (a3) is referred to. Hereinafter, the acid-stable structural unit (a4) will be described by showing an acid-stable monomer (hereinafter sometimes referred to as “acid-stable monomer (a4)”) from which the acid-stable structural unit (a4) can be derived.

式（ａ４−１）中、
Ｒ^a41は、炭素数１〜１２の１価の脂肪族炭化水素基又は炭素数６〜１２の１価の芳香族炭化水素基を表し、該１価の脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。Ａ^a41は、置換基を有していてもよい炭素数１〜６のアルカンジイル基又は式（ａ−ｇ１）

［式（ａ−ｇ１）中、
ｓは０又は１を表す。
Ａ^a42及びＡ^a44は、それぞれ独立に、置換基を有していてもよい炭素数１〜５の脂肪族炭化水素基を表す。
Ａ^a43は、置換基を有していてもよい炭素数１〜５の脂肪族炭化水素基又は単結合を表す。
Ｘ^a41及びＸ^a42は、それぞれ独立に、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
ただし、Ａ^a42、Ａ^a43、Ａ^a44、Ｘ^a41及びＸ^a42の炭素数の合計は７以下である。］
で表される基を表す。
Ｒ^a42は、置換基を有していてもよい脂肪族炭化水素基を表す。該脂肪族炭化水素基は部分的に、炭素炭素不飽和結合を有していてもよいが、炭素炭素不飽和結合を有さない脂肪族飽和炭化水素基が好ましい。該脂肪族飽和炭化水素基としては、アルキル基（当該アルキル基は直鎖でも分岐していてもよい）及び脂環式炭化水素基、並びに、アルキル基及び脂環式炭化水素基を組み合わせた脂肪族炭化水素基などが挙げられる。 A specific example of the acid stable monomer (a4) is, for example, a monomer represented by the following formula (a4-1) (hereinafter sometimes referred to as “monomer (a4-1)”). As will be described later, this monomer (a4-1) preferably has a fluorine atom.

In formula (a4-1),
R ^a41 represents a monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and a methylene group constituting the monovalent aliphatic hydrocarbon group. May be replaced by an oxygen atom or a carbonyl group. A ^a41 is an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a formula (a-g1).

[In the formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent an ^optionally substituted aliphatic hydrocarbon group having 1 to 5 carbon atoms.
A ^a43 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent or a single bond.
X ^a41 and X ^a42 each independently represent an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less. ]
Represents a group represented by
R ^a42 represents an aliphatic hydrocarbon group which may have a substituent. The aliphatic hydrocarbon group may partially have a carbon-carbon unsaturated bond, but an aliphatic saturated hydrocarbon group having no carbon-carbon unsaturated bond is preferable. Examples of the aliphatic saturated hydrocarbon group include an alkyl group (the alkyl group may be linear or branched), an alicyclic hydrocarbon group, and an aliphatic combination of an alkyl group and an alicyclic hydrocarbon group. Group hydrocarbon group and the like.

^Among the aliphatic hydrocarbon groups ^represented by R ^a41 , the alkyl group and the aromatic hydrocarbon group include those already exemplified in the respective ranges of the carbon number.

［式（ａ−ｇ３）中、
Ｘ^a43は、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^a45は、ハロゲン原子を有していてもよい炭素数３〜１７の脂肪族炭化水素基を表す。］
つまり、Ｒ^a42は、以下の式（ａ−ｇ２）で表される基であることが好ましい。

［式（ａ−ｇ２）中、
Ａ^a46は、ハロゲン原子を有していてもよい炭素数３〜１７の脂肪族炭化水素基を表す。
Ｘ^a44は、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^a47は、ハロゲン原子を有していてもよい炭素数３〜１７の脂肪族炭化水素基を表す。
ただし、Ａ^a46、Ａ^a47及びＸ^a44の炭素数の合計は１８以下である。］ Further, the aliphatic hydrocarbon group R ^a42 may not have have a substituent, but when R ^a42 is an aliphatic hydrocarbon group having a substituent group. Such a substituent is preferably a halogen atom or a group represented by the formula (a-g3).

[In the formula (a-g3),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents an aliphatic hydrocarbon group having 3 to 17 carbon atoms which may have a halogen atom. ]
That is, R ^a42 is preferably a group represented by the following formula (a-g2).

[In the formula (a-g2),
A ^a46 represents an aliphatic hydrocarbon group having 3 to 17 carbon atoms which may have a halogen atom.
X ^a44 represents a carbonyloxy group or an oxycarbonyl group.
A ^a47 represents an aliphatic hydrocarbon group having 3 to 17 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of A ^a46 , A ^a47 and X ^a44 is 18 or less. ]

Preferred R ^a42 , an aliphatic hydrocarbon group having a substituent selected from the group consisting of a halogen atom and a group represented by formula (a-g3) (a group represented by formula (a-g2)) Detailed description.

  First, an aliphatic hydrocarbon group having a halogen atom will be described. Such an aliphatic hydrocarbon group is typically an alkyl group having a halogen atom and an alicyclic hydrocarbon group having a halogen atom (preferably a cycloalkyl group having a halogen atom). The alkyl group having a halogen atom is one in which part or all of the hydrogen atoms constituting the alkyl group are substituted with halogen atoms. Similarly, an alicyclic hydrocarbon group having a halogen atom is one in which part or all of the hydrogen atoms constituting the alicyclic hydrocarbon group are substituted with halogen atoms. The halogen atom contained in the alkyl group having a halogen atom and the alicyclic hydrocarbon group having a halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, or a combination thereof, but a fluorine atom Is particularly preferred.

When the monomer (a4-1) in which R ^a42 is an aliphatic hydrocarbon group having a fluorine atom is shown as a specific example in the case where A ^a41 is a preferable ethylene group, the following formula (a4-1-1) to And a monomer (a4-1) represented by the formula (a4-1-22).

When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, a perfluoroalkyl group in which all of the hydrogen atoms constituting the alkyl group are substituted with fluorine atoms, or all of the hydrogen atoms constituting the cycloalkyl group are fluorine atoms. A perfluorocycloalkyl group substituted with is more preferable. Among the specific examples described above, the monomer (a4-1) in which R ^a42 is a perfluoroalkyl group or a perfluorocycloalkyl group includes the formula (a4-1-3), the formula (a4-1-4), the formula ( a4-1-7), formula (a4-1-8), formula (a4-1-11), formula (a4-1-12), formula (a4-1-15), formula (a4-1-16) ), Formula (a4-1-19), formula (a4-1-20), formula (a4-1-21), and formula (a4-1-22). Further, R ² is preferably a perfluoroalkyl group, and examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Is exemplified. More preferably, it is a C1-C6 perfluoroalkyl group, Most preferably, it is a C1-C3 perfluoroalkyl group.

^Next , the ^case where R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g3) will be described. The aliphatic hydrocarbon group may have one or a plurality of groups represented by the formula (a-g3), but the carbon atom contained in the group represented by the formula (a-g3) The total carbon number of the aliphatic hydrocarbon group including the number of is preferably 15 or less, and more preferably 12 or less. In order to satisfy such a preferable total number of carbon atoms, a group having one group represented by the formula (a-g3) is preferable as R ^a42 .

［式（ａ４−１’）中、
すべての符号はいずれも、前記と同義である。］ The monomer (a4-1) in which R ^a42 is an aliphatic hydrocarbon group having one group represented by the formula (a-g2) is specifically represented by the following formula (a4-1 ′). (Hereinafter referred to as “monomer (a4-1 ′)” in some cases).

[In the formula (a4-1 ′),
All symbols are as defined above. ]

In the monomer (a4-1 ′), both A ^a46 and A ^a47 may have a halogen atom, but A ^a46 is an aliphatic hydrocarbon group having a halogen atom, or A ^a47 is a halogen atom. The aliphatic hydrocarbon group having Furthermore, A ^a46 is preferably an aliphatic hydrocarbon group having a halogen atom, and among them, A ^a46 is more preferably an alkanediyl group having a fluorine atom, and particularly preferably a perfluoroalkanediyl group. The “perfluoroalkanediyl group” refers to an alkanediyl group in which all of the hydrogen atoms are substituted with fluorine atoms.

When the compound (a4-1 ′) in which R ^a42 is a perfluoroalkanediyl group is exemplified when A ^a41 is an ethylene group, the following formulas (a4-1′-1) to (a4-1′-22) ) Represented by a monomer (a4-1 ′).

A ^a46 and A ^a47 are arbitrarily selected in a range where the total number of carbon atoms is 17 or less, and the carbon number of A ^a46 is preferably in the range of 1 to 6, and more preferably in the range of 1 to 3.
On the other hand, the carbon number of A ^a47 is preferably in the range of 4 to 15, more preferably in the range of 5 to 12. Particularly preferred A ¹⁴ is an alicyclic hydrocarbon group having 6 to 12 carbon atoms, and as the alicyclic hydrocarbon group, a cyclohexyl group and an adamantyl group are particularly preferred.

このような構造を有するモノマー（ａ４−１’）は、前記の具体例の中では、式（ａ４−１’−９）〜式（ａ４−１’−２０）で表される化合物が該当する。 Among the combinations of A ^a46 and A ^a47, the more preferable, * - is represented by the partial structure represented by A ^a46 -X ^a44 -A ^a47 (* represents a bond to a carbonyl group), the following structure Is mentioned.

The monomer (a4-1 ′) having such a structure corresponds to the compound represented by the formula (a4-1′-9) to the formula (a4-1′-20) in the above specific examples. .

  When the resin (A) has a structural unit derived from the monomer (a4-1), the content ratio thereof is preferably in the range of 1 to 20 mol% with respect to all the structural units of the resin (A). The range of 15 mol% is more preferable, and the range of 3 to 10 mol% is more preferable.

  As described above, the structural unit (a1-1), the structural unit (a1-2), the other structural unit (a1), and the acid stable structural unit suitable as the structural unit (a1) of the resin (A). Although the acid stable structural unit (a2), the acid stable structural unit (a3), and the acid stable structural unit (a4) have been described in detail, the structural unit other than these may be included. Mention may be made of structural units well known in the art. Although the resin (A) having an acid labile group in the molecule has been described here, the resist composition contains a resin having no acid labile group in addition to the resin (A). May be.

<Method for producing resin (A)>
The resin (A) is obtained by copolymerizing the monomer (a1) for deriving the structural unit (a1), more preferably the monomer (a1) and an acid stable monomer, and more preferably the structural unit. (A1-1) and / or monomer (a1) for deriving structural unit (a1-2) and acid-stable monomer for deriving acid-stable structural unit (a2) and / or acid-stable structural unit (a3) Polymerized. For example, when the resist composition is used for EUV exposure, the monomer (a1) that induces the structural unit (a1-1) and / or the structural unit (a1-2), and the acid stable structural unit (a2- And an acid-stable monomer derived from 0).
The resin (A) further preferably has a structural unit (a1-1) having an adamantyl group as the structural unit (a1). The resin (A) can be produced by subjecting the monomer as described above to a known polymerization method (for example, radical polymerization method) and polymerizing (copolymerizing) it.

  The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less). In addition, the weight average molecular weight here is calculated | required as a conversion value of a standard polystyrene reference | standard by gel permeation chromatography analysis. Detailed analysis conditions for this analysis are described in the Examples of the present application.

<Basic compound (C)>
The resist composition preferably contains a basic compound (C). Such a basic compound (C) is called a quencher in the technical field in question. 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) and a compound represented by the formula (C1-1), more preferably the formula The compound represented by (C1-1) is mentioned.

［式（Ｃ１）中、
Ｒ^c1、Ｒ^c2及びＲ^c3は、それぞれ独立に、水素原子、炭素数１〜６のアルキル基、炭素数５〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基を表し、該アルキル基及び該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基、アミノ基又は炭素数１〜６のアルコキシ基で置換されていてもよく、該芳香族炭化水素基に含まれる水素原子は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］

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

［式（Ｃ１−１）中、
Ｒ^c2及びＲ^c3は、前記と同義である。
Ｒ^c4は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基を表す。
ｍ３は０〜３の整数を表し、ｍ３が２以上のとき、複数のＲ^c4は、互いに同一でも異なってもよい。］

[In the formula (C1-1),
R ^c2 and R ^c3 are as defined 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, a plurality of R ^{c4 s} may be the same as or different from each other. ]

［式（Ｃ２）、式（Ｃ３）及び式（Ｃ４）中、
Ｒ^c5、Ｒ^c6、Ｒ^c7及びＲ^c8は、それぞれ独立に、Ｒ^c1と同義である。
Ｒ^c9は、炭素数１〜６のアルキル基、炭素数３〜６の脂環式炭化水素基又は炭素数２〜６のアルカノイル基を表す。
ｎ３は０〜８の整数を表し、ｎ３が２以上のとき、複数のＲ^c9は、互いに同一でも異なってもよい。］

[In Formula (C2), Formula (C3) and Formula (C4),
R ^c5 , R ^c6 , R ^c7 and R ^c8 are each independently synonymous with 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 may be the same as or different from each other. ]

［式（Ｃ５）及び式（Ｃ６）中、
Ｒ^c10、Ｒ^c11、Ｒ^c12、Ｒ^c13及びＲ^c16は、それぞれ独立に、Ｒ^c1と同義である。
Ｒ^c14、Ｒ^c15及びＲ^c17は、それぞれ独立に、Ｒ^c4と同義である「。
ｏ３及びｐ３は、それぞれ独立に０〜３の整数を表し、ｏ３が２以上であるとき、複数のＲ^c14は互いに同一でも異なってもよい。ｐ３が２以上であるとき、複数のＲ^c15は互いに同一でも異なってもよい。
Ｌ^c1は、炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

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

［式（Ｃ７）及び式（Ｃ８）中、
Ｒ^c18、Ｒ^c19及びＲ^c20は、それぞれ独立に、Ｒ^c4と同義である。
ｑ３、ｒ３及びｓ３は、それぞれ独立に０〜３の整数を表し、ｑ３が２以上であるとき、複数のＲ^c18は互いに同一でも異なってもよい。ｒ３が２以上であるとき、複数のＲ^c19は互いに同一でも異なってもよい。ｓ３が２以上であるとき、複数のＲ^c20は互いに同一でも異なってもよい。
Ｌ^c2は、単結合又は炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

[In Formula (C7) and Formula (C8),
R ^c18, R ^c19 and R ^c20 in each occurrence independently has 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 may be the same or different from each other. When r3 is 2 or more, the plurality of R ^c19 may be the same as or different from each other. When s3 is 2 or more, the plurality of R ^c20 may be the same as or different from each other.
L ^c2 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

  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 thereof include diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, and 4,4′-diamino-3,3′-diethyldiphenylmethane. Propyl aniline. 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 Examples include ammonium hydroxide, tetra-n-butylammonium salicylate, and choline.

<Solvent (D)>
The present resist composition may contain a solvent (D). The solvent (D) depends on the type and amount of the salt represented by the formula (I) and the resin (A), and in the production of a resist pattern described later, the resist composition is applied on the substrate. From the viewpoint of good coating properties, an optimum one can be selected as appropriate.

  Examples of the solvent (D) 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 Examples thereof include esters such as ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone. A solvent (D) may be used individually by 1 type, and may use 2 or more types together.

<Other ingredients>
The resist composition comprises an acid generator containing a salt (I) and a resin (A), preferably an acid generator containing a salt (I), a resin (A), and a basic compound (C) used as necessary. ) And a solvent (D), but may contain components other than the basic compound (C) and the solvent (D) used as necessary. This component is referred to as “component (F)”. Such component (F) is an additive known in the art, and examples thereof include a sensitizer, a dissolution inhibitor, a surfactant, a stabilizer, and a dye.

<Preparation method of the present resist composition>
Then, the preparation method of this resist composition is demonstrated.
The resist composition comprises a salt (I) and a resin (A) and a solvent (D), a basic compound (C), an acid generator (B), a basic compound (C) and / or used as necessary. It can prepare by mixing a component (F). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing should just select a suitable temperature range from the range of 10-40 degreeC according to the solubility with respect to solvent (D), such as resin (A) kind, resin (A), etc., and mixing time Is preferably 0.5 to 24 hours, depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.

  The content ratio of the acid generator in the resist composition is preferably 40% by mass or less, more preferably 35% by mass or less, and preferably 1% by mass or more, more preferably based on the solid content of the resist composition. Is 3% by mass or more. In addition, solid content here means the sum total of what remove | excluded the solvent (D) from this resist composition. The solid content can be determined by subjecting the resist composition to analysis such as liquid chromatography and gas chromatography.

  The content of the salt (I) is preferably 10 parts by mass or more, more preferably 30 parts by mass or more with respect to 100 parts by mass of the total amount of the acid generator. In the present resist composition, only a salt substantially represented by the formula (I) can be used as an acid generator. As the acid generator other than the salt (I), the acid generator (B) is preferable.

  A preferable range of the content ratio of the resin (A) in the resist composition is determined based on the solid content of the resist composition. Specifically, the resin (A) is preferably 80% by mass or more based on the mass of the solid content.

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

  The content ratio of the solvent (D) in the present resist composition is 90% by mass or more, preferably 92% by mass or more, more preferably 94% by mass or more, based on the total mass of the present resist composition. 0.9 mass% or less, preferably 99 mass% or less.

  When the resist composition contains the component (F), an appropriate content can be determined according to the type of the component (F).

  Thus, each of the acid generator containing the salt (I), the resin (A), and the basic compound (C), the solvent (D), or the component (F) used as necessary is mixed in a preferable content. Thereafter, the resist composition can be prepared by filtration using a filter having a pore size of about 0.003 to 0.2 μm.

<Method for producing resist pattern>
Specifically showing a method for producing a resist pattern using the present resist composition,
(1) a step of applying the resist composition 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;
Examples thereof include (4) a step of heating the composition layer after exposure and (5) a step of developing the composition layer after heating. Hereinafter, each of the steps shown here is referred to as “step (1)” to “step (5)”.

  Application of the resist composition on the substrate in the step (1) can be performed by a coating apparatus widely used for applying a resist material for semiconductor microfabrication, such as a spin coater. Thus, a coating film made of a resist composition is formed on the substrate. The film thickness of the coating film can be adjusted by variously adjusting the conditions (coating conditions) of the coating apparatus, and by applying an appropriate preliminary experiment, the coating film can be applied to have a desired film thickness. You can choose the conditions. Various substrates to be subjected to microfabrication can be selected as the substrate before applying the resist composition. The substrate may be washed or an antireflection film may be formed before applying the resist composition. For example, a commercially available composition for an organic antireflection film can be used for forming the antireflection film.

In the step (2), the solvent (D) is removed from the present resist composition coated on the substrate, that is, the coated film. Such solvent removal is performed by evaporating the solvent from the coating film by, for example, heating means using a heating device such as a hot plate (so-called pre-baking), decompressing means using a decompressing device, or a combination of these means. Is done. The conditions for the heating means and the decompression means can be selected according to the type of the solvent (D) contained in the resist composition. For example, in the case of a hot plate, the surface temperature of the hot plate is in the range of about 50 to 200 ° C. It is preferable to do. In the decompression means, after the substrate on which the coating film is formed is sealed in an appropriate decompressor, the internal pressure of the decompressor may be set to about 1 to 1.0 × 10 ⁵ Pa. Thus, the composition layer is formed on the substrate by removing the solvent from the coating film.

Step (3) is a step of exposing the composition layer, and preferably the composition layer is exposed using an exposure machine. At this time, exposure is performed through a mask (photomask) on which a desired pattern to be finely processed is formed. As an exposure light source of the exposure machine, an ultraviolet light source such as a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ excimer laser (wavelength 157 nm), or a solid-state laser light source (YAG In addition, various lasers such as a laser beam from a laser beam from a semiconductor laser or the like to emit a harmonic laser beam in the far ultraviolet region or the vacuum ultraviolet region can be used. The exposure machine may be an immersion exposure machine. The exposure machine may irradiate an electron beam or extreme ultraviolet light (EUV). In this specification, irradiating these radiations may be collectively referred to as “exposure”. When the exposure light source is an electron beam, a desired pattern may be directly drawn without using a photomask.

  As described above, by exposing through a mask, an exposed portion (exposed portion) and an unexposed portion (unexposed portion) are generated in the composition layer. In the composition layer of the exposed portion, the salt (I) and the acid generator (B) contained in the composition layer generate an acid upon receiving exposure energy, and further, by the action with the generated acid, “insoluble in an alkaline aqueous solution”. Alternatively, the acid labile group in the resin (A) of the resin which is hardly soluble and becomes soluble in an alkaline aqueous solution by the action of an acid generates a hydrophilic group by a deprotection reaction. As a result, the composition layer of the exposed portion The resin (A) in (1) is soluble in an alkaline aqueous solution. On the other hand, since the exposure energy is not received in the unexposed area, the resin (A) remains insoluble or hardly soluble in the alkaline aqueous solution. Thus, since the composition layer in the exposed part and the composition layer in the unexposed part are remarkably different in solubility in the alkaline aqueous solution, a resist pattern can be formed by development with the alkaline aqueous solution.

  In the step (4), a heat treatment (so-called post-exposure baking) for further promoting the progress of the deprotecting group reaction that may occur in the exposed portion is performed. Such heat treatment is preferably the heating means using the hot plate shown in the step (2). In addition, when performing hot plate heating in a process (4), about 50-200 degreeC is preferable and the surface temperature of this hot plate has more preferable about 70-150 degreeC. The deprotection reaction is promoted by the heat treatment.

  Step (5) is a step of developing the heated composition layer using a developer, usually 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., for example, and the development time is preferably 5 to 300 seconds, for example.

By selecting the type of developer, a positive resist pattern or a negative resist pattern can be produced.
When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline). The alkali developer may contain a surfactant.
It is preferable to wash the resist pattern with ultrapure water after development, and then remove the water remaining on the substrate and the pattern.

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

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

  According to the resist pattern manufacturing method including the steps (1) to (5) as described above, a resist pattern can be manufactured with excellent line edge roughness due to the effect of the present resist composition.

<Application>
This resist composition is suitable as a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) irradiation, or a resist composition for an EUV exposure machine. It can be used for fine processing of semiconductors.

Hereinafter, the present invention will be described in detail by way of examples.
In Examples and Comparative Examples, “%” and “part” representing the content and the amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value obtained by gel permeation chromatography (HLC-8120GPC, manufactured by Tosoh Corporation, three columns are “TSKgel Multipore HXL-M”, and the solvent is tetrahydrofuran) using polystyrene as a standard product.
Column: TSKgel Multipore H _XL -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)

  The structure of the compound was confirmed by measuring the molecular peak using mass spectrometry (LC is model 1100 manufactured by Agilent, and MASS is LC / MSD manufactured by Agilent). In the following examples, the value of this molecular peak is indicated by “MASS”.

式（Ｉ−１−ａ）で表される塩５．００部及びクロロホルム３０．００部を仕込み、４０℃で３０分間攪拌した。その後、式（Ｉ−１−ｂ）で表される化合物２．０４部を添加し、７０℃程度まで昇温した後、同温度で２時間攪拌し、式（Ｉ−２−ｃ）で表される化合物を含む溶液を得た。得られた式（Ｉ−２−ｃ）で表される化合物を含む溶液に、２３℃で、式（Ｉ−２−ｃ）で表される化合物２．４２部及びクロロホルム１５．００部の混合溶液を滴下した後、２３℃で１８時間攪拌した。得られた反応物に、２％シュウ酸水溶液９０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水３０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。回収された有機層に活性炭１．００部を加えて攪拌し、ろ過した。得られたろ液を濃縮し、ｔｅｒｔ−ブチルメチルエーテル４０部を加えて攪拌した後、ろ過することにより、式（Ｉ−１）で表される塩５．８９部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３７２．８ Example 1 [Synthesis of a salt represented by the formula (I-1)]

5.00 parts of a salt represented by the formula (I-1-a) and 30.00 parts of chloroform were charged and stirred at 40 ° C. for 30 minutes. Thereafter, 2.04 parts of a compound represented by the formula (I-1-b) was added, the temperature was raised to about 70 ° C., and the mixture was stirred at the same temperature for 2 hours, and represented by the formula (I-2-c). A solution containing the compound to be obtained was obtained. The solution containing the compound represented by the formula (I-2-c) thus obtained was mixed with 2.42 parts of the compound represented by the formula (I-2-c) and 15.00 parts of chloroform at 23 ° C. After the solution was added dropwise, the mixture was stirred at 23 ° C. for 18 hours. To the obtained reaction product, 90 parts of a 2% aqueous oxalic acid solution was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 30 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. To the collected organic layer, 1.00 part of activated carbon was added, stirred and filtered. The obtained filtrate was concentrated, 40 parts of tert-butyl methyl ether was added and stirred, and then filtered to obtain 5.89 parts of the salt represented by the formula (I-1).
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (−) Spectrum): M ^- 372.8

式（Ｉ−２−ａ）で表される塩８．１１部及びアセトニトリル４０．６９部を仕込み、４０℃で３０分間攪拌した。その後、式（Ｉ−２−ｂ）で表される化合物４．２１部を添加し、７０℃程度まで昇温した後、同温度で２時間攪拌し、式（Ｉ−２−ｃ）で表される化合物を含む溶液を得た。得られた式（Ｉ−２−ｃ）で表される化合物を含む溶液に、２３℃で、式（Ｉ−２−ｃ）で表される化合物５．００部及びクロロホルム１５．００部
の混合溶液を滴下した後、２３℃で１８時間攪拌した。得られた反応物を濃縮した後、濃縮物に、クロロホルム９０部及び２％シュウ酸水溶液１７５部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水４５部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。回収された有機層に活性炭１．００部を加えて攪拌し、ろ過した。得られたろ液を濃縮し、ｔｅｒｔ−ブチルメチルエーテル７０部を加えて攪拌した後、ろ過することにより、式（Ｉ−２）で表される塩９．８１部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ４７８．８ Example 2 [Synthesis of a salt represented by the formula (I-2)]

8.11 parts of the salt represented by the formula (I-2-a) and 40.69 parts of acetonitrile were charged and stirred at 40 ° C. for 30 minutes. Thereafter, 4.21 parts of the compound represented by the formula (I-2-b) was added, and the temperature was raised to about 70 ° C., followed by stirring at the same temperature for 2 hours, and represented by the formula (I-2-c). A solution containing the compound to be obtained was obtained. The solution containing the compound represented by the formula (I-2-c) thus obtained was mixed at 23 ° C. with 5.00 parts of the compound represented by the formula (I-2-c) and 15.00 parts of chloroform. After the solution was added dropwise, the mixture was stirred at 23 ° C. for 18 hours. After concentrating the obtained reaction product, 90 parts of chloroform and 175 parts of a 2% aqueous oxalic acid solution were added to the concentrate, followed by stirring at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 45 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. To the collected organic layer, 1.00 part of activated carbon was added, stirred and filtered. The obtained filtrate was concentrated, 70 parts of tert-butyl methyl ether was added and stirred, and then filtered to obtain 9.81 parts of the salt represented by the formula (I-2).
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (−) Spectrum): M ^- 478.8

式（Ｉ−１１−ａ）で表される塩を、特開２００８−１２７３６７号公報に記載された方法で合成した。式（Ｉ−１１−ａ）で表される塩５．００部及びアセトニトリル３０部を仕込み、４０℃で３０分間攪拌し、式（Ｉ−１１−ｂ）で表される化合物２．２２部を仕込み、５０℃で１時間攪拌することにより、式（Ｉ−１１−ｃ）で表される化合物を含む溶液を得た。 Example 3 [Synthesis of a salt represented by the formula (I-11)]

A salt represented by the formula (I-11-a) was synthesized by the method described in JP-A-2008-127367. 5.00 parts of a salt represented by the formula (I-11-a) and 30 parts of acetonitrile are charged and stirred at 40 ° C. for 30 minutes to obtain 2.22 parts of a compound represented by the formula (I-11-b). The solution containing the compound represented by the formula (I-11-c) was obtained by charging and stirring at 50 ° C. for 1 hour.

得られた式（Ｉ−１１−ｃ）で表される化合物を含む溶液に、式（Ｉ−１１−ｄ）で表される化合物２．７４部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム５０部及びイオン交換水２５部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮した後、得られた濃縮物に、アセトニトリル３０部を添加して溶解し、濃縮し、酢酸エチル２０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル２０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−１１−ｅ）で表される塩６．２２部を得た。

To the obtained solution containing the compound represented by the formula (I-11-c), 2.74 parts of the compound represented by the formula (I-11-d) was charged and stirred at 23 ° C. for 1 hour. Into the obtained reaction mass, 50 parts of chloroform and 25 parts of ion-exchanged water were added 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. After the filtrate was concentrated, 30 parts of acetonitrile was added to the resulting concentrate to dissolve it, concentrated, 20 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 20 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 6.22 parts of the salt represented by the formula (I-11-e).

式（Ｉ−１１−ｅ）で表される塩１．００部、クロロホルム１０部並びに１Ｎ塩酸水溶液２．６５部及びメタノール２．６５部の混合溶液を仕込み、２３℃で１５時間撹拌した。その後、１Ｎ炭酸水素ナトリウム水溶液１０部を仕込み、攪拌後、分液した。回収された有機層に、イオン交換水１０部を仕込み、攪拌後、分液した。この水洗を３回行った。回収された有機層に活性炭１．００部を添加、攪拌後、濾過して濾液を回収し、該濾液を濃縮することにより、式（Ｉ−１１−ｆ）で表される塩０．７５部を得た。

A mixed solution of 1.00 parts of the salt represented by the formula (I-11-e), 10 parts of chloroform, 2.65 parts of 1N hydrochloric acid aqueous solution and 2.65 parts of methanol was charged and stirred at 23 ° C. for 15 hours. Thereafter, 10 parts of a 1N aqueous sodium hydrogen carbonate solution was added, and the mixture was stirred and separated. To the recovered organic layer, 10 parts of ion-exchanged water was added, and after stirring, the liquid was separated. This washing with water was performed three times. 1.00 part of activated carbon is added to the recovered organic layer, stirred, and then filtered to collect the filtrate. The filtrate is concentrated to obtain 0.75 part of the salt represented by the formula (I-11-f). Got.

式（Ｉ−１１−ｆ）で表される塩０．４８部及びアセトニトリル１０部を仕込み、４０℃で３０分間攪拌し、式（Ｉ−１１−ｂ）で表される化合物０．１５部を仕込み、５０℃で１時間攪拌することにより、式（Ｉ−１１−ｇ）で表される塩を含む溶液を得た。

0.48 part of a salt represented by the formula (I-11-f) and 10 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and 0.15 part of a compound represented by the formula (I-11-b) was added. The solution containing the salt represented by the formula (I-11-g) was obtained by charging and stirring at 50 ° C. for 1 hour.

得られた式（Ｉ−１１−ｇ）で表される塩を含む溶液に、式（Ｉ−１１−ｈ）で表される化合物０．１７部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム５０部及びイオン交換水２０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮した後、得られた濃縮物に、アセトニトリル３０部を添加して溶解し、濃縮し、酢酸エチル３０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−１１）で表される塩０．５２部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５５０．９

To the obtained solution containing the salt represented by the formula (I-11-g), 0.17 part of the compound represented by the formula (I-11-h) was charged and stirred at 23 ° C. for 1 hour. To the obtained reaction mass, 50 parts of chloroform and 20 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. After concentrating the filtrate, 30 parts of acetonitrile was added to the resulting concentrate to dissolve, concentrated, 30 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 30 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 0.52 parts of the salt represented by the formula (I-11).
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 550.9

式（Ｉ−１１−ｆ）で表される塩０．４８部及びアセトニトリル１０部を仕込み、４０℃で３０分間攪拌し、式（Ｉ−１１−ｂ）で表される化合物０．１５部を仕込み、５０℃で１時間攪拌することにより、式（Ｉ−１１−ｇ）で表される塩を含む溶液を得た。 Example 4 [Synthesis of salt represented by formula (I-12)]

0.48 part of a salt represented by the formula (I-11-f) and 10 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and 0.15 part of a compound represented by the formula (I-11-b) was added. The solution containing the salt represented by the formula (I-11-g) was obtained by charging and stirring at 50 ° C. for 1 hour.

得られた式（Ｉ−１１−ｇ）で表される塩を含む溶液に、式（Ｉ−１２−ｈ）で表される化合物０．２６部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム５０部及びイオン交換水２０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮した後、得られた濃縮物に、アセトニトリル３０部を添加して溶解し、濃縮し、酢酸エチル３０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−１２）で表される塩０．５１部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ６５６．９

In a solution containing the salt represented by the formula (I-11-g) thus obtained, 0.26 part of the compound represented by the formula (I-12-h) was charged and stirred at 23 ° C. for 1 hour. To the obtained reaction mass, 50 parts of chloroform and 20 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. After concentrating the filtrate, 30 parts of acetonitrile was added to the resulting concentrate to dissolve, concentrated, 30 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 30 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 0.51 part of a salt represented by the formula (I-12).
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 656.9

以下、これらの化合物をその式番号に応じて、「モノマー（ａ１−１−２）」などという。 Synthesis of Resin (A) The compounds used for the synthesis of resin (A) are shown below.

Hereinafter, these compounds are referred to as “monomer (a1-1-2)” or the like according to the formula number.

Synthesis Example 1 [Synthesis of Resin A1]
As the monomer, using monomer (a1-1-2), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1), The molar ratio (monomer (a1-1-2): monomer (a1-2-3): monomer (a2-1-1): monomer (a3-2-3): monomer (a3-1-1)) , 30: 14: 6: 20: 30, and 1.5 mass times dioxane of 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 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 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 7.2. A copolymer A1 of × 10 ³ was obtained with a yield of 78%. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin A2]
As the monomer, using monomer (a1-1-2), monomer (a1-5-1), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1), The molar ratio (monomer (a1-1-2): monomer (a1-5-1): monomer (a2-1-1): monomer (a3-2-3): monomer (a3-1-1))) , 30: 14: 6: 20: 30, and 1.5 mass times dioxane of 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 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 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 7.2. A copolymer A2 of × 10 ³ was obtained with a yield of 78%. This resin A2 has the following structural units.

Synthesis Example 3: [Synthesis of Resin A3]
Monomer (1-1-2), monomer (a2-1-1) and monomer (a3-1-1) are mixed in a molar ratio [monomer (1-1-2): monomer (a2-1-1): Monomer (a3-1-1)] was mixed so as to be 50:25:25, and 1.5 mass times dioxane was further mixed with respect to the total mass of all monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. Then, this was heated at 80 ° C. for about 8 hours to carry out polymerization. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. Again, the obtained resin is dissolved in dioxane, poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered three times for reprecipitation purification. A copolymer having a weight average molecular weight of about 9.2 × 10 ³ was obtained in a yield of 60%. This copolymer has structural units derived from the following monomers derived from the monomer (1-1-2), the monomer (a2-1-1) and the monomer (a3-1-1), respectively. Yes, this is resin A3.

Synthesis Example 4 [Synthesis of Resin A4]
Monomer (a4-1-7) was used as a monomer, and 1.5 mass times dioxane of the total monomer amount was added to prepare a solution. Azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the solution in an amount of 0.7 mol% and 2.1 mol%, respectively, with respect to the total monomer amount, and these were added at 75 ° 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 resin thus obtained was dissolved again in dioxane, and the solution obtained by pouring the solution into a methanol / water mixed solvent was precipitated twice, and the resin was filtered twice to perform the reprecipitation operation twice. 8 × 10 ⁴ resin A4 (copolymer) was obtained with a yield of 77%. This resin A4 has the following structural units.

Synthesis Example 5 [Synthesis of Resin A5]
As the monomer, using monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-3), monomer (a3-2-3) and monomer (a3-1-1), The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-2-3): monomer (a3-1-1)] It mixed so that it might become 45: 14: 2.5: 22: 16.5, and 1.5 mass times propylene glycol monomethyl ether acetate of the total monomer amount was added, and it was set as the solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 0.95 mol% and 2.85 mol%, respectively, based on the total monomer amount, and these were added at 73 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / ion-exchanged water = 4/1 mixing solution to precipitate the resin, and the resin was filtered to obtain a resin A5 having a weight average molecular weight of 7.8 × 10 ³ (co-polymer). Polymer) with a yield of 73%. This resin A5 had the following structural units and was soluble in butyl acetate.

Examples 3-8, Comparative Example 1
<Preparation of resist composition>
Each component shown in Table 7 and the following solvent were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

Ｉ−２：式（Ｉ−２）で表される塩

Ｉ−１１：式（Ｉ−１１）で表される塩

Ｉ−１２：式（Ｉ−１２）で表される塩

酸発生剤Ｂ１−３：

酸発生剤Ｚ１：

酸発生剤Ｚ２：

<Acid generator>
I-1: salt represented by formula (I-1)

I-2: salt represented by formula (I-2)

I-11: salt represented by formula (I-11)

I-12: a salt represented by the formula (I-12)

Acid generator B1-3:

Acid generator Z1:

Acid generator Z2:

<Resin>
A1: Resin A1
A2: Resin A2
A3: Resin A3
A4: Resin A4
A5: Resin A5
<Basic compound: Quencher>
C1: 2,6-Diisopropylaniline

<Solvent>
Propylene glycol monomethyl ether acetate 265.0 parts Propylene glycol monomethyl ether 20.0 parts 2-heptanone 20.0 parts γ-butyrolactone 3.5 parts

<Evaluation of line edge roughness (LER) after immersion exposure of resist composition>
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. Subsequently, the 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 7. 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 bake (PEB) was performed for 60 seconds on the hot plate at the temperature described in the “PEB” column of Table 7, and further with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed to obtain a resist pattern.

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

<Line edge roughness evaluation (LER)>
The wall surface of the resist pattern after the lithography process is observed with a scanning electron microscope.
What is 4.0 nm or less ○,
What exceeded 4.0 nm was set as x.
Table 8 shows the results of the line edge roughness evaluation (LER) obtained as described above. The numbers in parentheses indicate the fluctuation width (nm) of the unevenness on the side wall.

<Development evaluation of organic solvent after immersion exposure of resist composition>
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. Subsequently, the 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 7. 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 exposure, post-exposure baking (PEB) is performed for 60 seconds at a temperature described in the “PEB” column of Table 7, and then paddle development is performed for 30 seconds with butyl acetate to obtain a resist pattern. It was.
In the obtained resist pattern, the exposure amount at which the 50 nm line and space pattern becomes an exposure amount of 1: 1 was defined as the effective sensitivity.

<Line edge roughness evaluation (LER)>
The wall surface of the resist pattern after the lithography process is observed with a scanning electron microscope.
What is 4.0 nm or less ○,
What exceeded 4.0 nm was set as x.
Table 9 shows the results of the line edge roughness evaluation (LER) obtained as described above. The numbers in parentheses indicate the fluctuation width (nm) of the unevenness on the side wall.

  If a resist composition containing the salt of the present invention as an acid generator is used, a resist pattern can be produced with excellent line edge roughness (LER).

Claims (7)

A salt represented by the formula (I).

[In the formula (I),
Q ¹ and Q ² are the same or different and each represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a (1 + m1) -valent saturated hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be replaced by a fluorine atom or a hydroxy group, and the saturated hydrocarbon group May be replaced with an oxygen atom or a carbonyl group.
X ¹ represents a chlorine atom or a bromine atom .
m1 represents 2 or 3, and a plurality of X ¹ may be the same or different each independently.
Z ⁺ represents an organic cation. ] -L ¹ - ^(X ₁₎ a group represented by _m1 is salt according to claim 1, wherein a group represented by the formula ^(L 1 -1).

[In the formula (L ¹ -1),
X ⁰ represents an optionally substituted (1 + m1) -valent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group is replaced with a fluorine atom or a hydroxy group. The methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
X ¹ and m ¹ represent the same meaning as described above.
* Represents a bond with a carbon atom of C (Q ¹ ) (Q ² ). ] The salt according to claim 1 or 2, wherein Z ⁺ is an arylsulfonium cation.   The acid generator which contains the salt in any one of Claims 1-3 as an active ingredient.   The acid generator according to claim 4 and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution, and can be dissolved in an alkaline aqueous solution by acting with an acid. Resist composition which is resin.   Furthermore, the resist composition of Claim 5 containing a basic compound. (1) The process of apply | coating the resist composition of Claim 5 or 6 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 method for producing a resist pattern, comprising a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.