JP2016188385A - Resin, resist composition and method for manufacturing resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition that can give a resist pattern having excellent line edge roughness, and a resin included in the resist composition.SOLUTION: The resin has a structural unit represented by formula (I). In formula (I), Rrepresents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom; Arepresents a single bond,-A-O-,-A-CO-O-,-A-CO-O-A-CO-O- or-A-O-CO-A-O-, where * represents a coupling bond to -O-; and Aand Aeach independently represent an alkylene group having 1 to 6 carbon atoms. The resist composition contains the above resin.SELECTED DRAWING: None

Description

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

  A resist composition used for semiconductor microfabrication using a lithography technique contains a resin, an acid generator, and a solvent.

For example, in Patent Document 1, as a resin for a resist composition, a structural unit represented by the formula (u-A), a structural unit represented by the formula (u-B), and a formula (u-C) are used. Resins composed of structural units are described.

JP 2001-240625 A

  A resist composition containing a conventional resin may not always satisfy the line edge roughness (LER) of the resulting resist pattern.

［式（Ｉ）中、
Ｒ^１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。
Ａ^１は、単結合、^＊−Ａ^２−Ｏ−、^＊−Ａ^２−ＣＯ−Ｏ−、^＊−Ａ^２−ＣＯ−Ｏ−Ａ^２−ＣＯ−Ｏ−又は^＊−Ａ^２−Ｏ−ＣＯ−Ａ^２−Ｏ−を表す。
＊は−Ｏ−との結合手を表す。
Ａ^２は、炭素数１〜６のアルカンジイル基を表す。］ The present invention includes the following inventions.
[1] A resin having a structural unit represented by the formula (I).

[In the formula (I),
R ¹ represents a C 1-6 alkyl group, a hydrogen atom or a halogen atom which may have a halogen atom.
A ¹ is a single bond, ^* —A ² —O—, ^* —A ² —CO—O—, ^* —A ² —CO—O—A ² —CO—O— or ^* —A ² —O—CO. -A represents a ² -O-.
* Represents a bond with -O-.
A ² represents an alkanediyl group having 1 to 6 carbon atoms. ]

[2] The resin according to [1], which is insoluble or hardly soluble in an alkaline aqueous solution and can be dissolved in an alkaline aqueous solution by the action of an acid.

[3] A resist composition containing the resin according to [1] or [2], an acid generator, and a solvent.

[4] The resist composition according to [3], further comprising a basic compound.

[5] (1) A step of applying the resist composition according to [3] or [4] on a substrate,
(2) a step of removing the solvent from the composition after coating to form a composition layer;
(3) a step of exposing the composition layer,
(4) A method for producing a resist pattern, comprising a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

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

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

［式（Ｉ）中、
Ｒ^１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。
Ａ^１は、単結合、^＊−Ａ^２−Ｏ−、^＊−Ａ^２−ＣＯ−Ｏ−、^＊−Ａ^２−ＣＯ−Ｏ−Ａ^２−ＣＯ−Ｏ−又は^＊−Ａ^２−Ｏ−ＣＯ−Ａ^２−Ｏ−を表す。
＊は−Ｏ−との結合手を表す。
Ａ^２は、炭素数１〜６のアルカンジイル基を表す。］ <Structural unit (I)>
The structural unit (I) is represented by the formula (I). Again, formula (I) is shown below.

[In the formula (I),
R ¹ represents a C 1-6 alkyl group, a hydrogen atom or a halogen atom which may have a halogen atom.
A ¹ is a single bond, ^* —A ² —O—, ^* —A ² —CO—O—, ^* —A ² —CO—O—A ² —CO—O— or ^* —A ² —O—CO. -A represents a ² -O-.
* Represents a bond with -O-.
A ² represents an alkanediyl group having 1 to 6 carbon atoms. ]

Examples of the alkyl group for R ¹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, and n-hexyl group. Preferably, it is a C1-C4 alkyl group, More preferably, they are a methyl group and an ethyl group.

Examples of the halogen atom for R ¹ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkyl group having a halogen atom for R ¹ include perfluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group, perfluorohexyl. A group, a perchloromethyl group, a perbromomethyl group, a periodomethyl group, and the like.
Among the above specific examples, R ¹ is preferably a hydrogen atom or a methyl group.

A ¹ is a single bond, ^* —A ² —O—, ^* —A ² —CO—O—, ^* —A ² —CO—O—A ² —CO—O— or ^* —A ² —O—CO. —A ² —O— is represented, and A ² is an alkanediyl group having 1 to 6 carbon atoms. 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 and hexane. A linear alkanediyl group such as a -1,6-diyl group or a linear alkanediyl group, an alkyl group (particularly, an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, Having a side chain of isopropyl group, butyl group, sec-butyl group, tert-butyl group, etc., for example, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2- Examples include branched alkanediyl groups such as methylpropane-1,2-diyl group, pentane-1,4-diyl group and 2-methylbutane-1,4-diyl group.
Among the above specific examples, A ¹ is preferably a single bond or ^* —A ² —CO—O—, and is a single bond, —CH ₂ —CO—O— or —C ₂ H ₄ —CO—O. -Is more preferable.

Specific examples of the structural unit (I) are shown below.

Regarding the structural units represented by formula (aa-1) to formula (aa-6), structural units in which the methyl group corresponding to R ¹ is replaced by a hydrogen atom are also exemplified as specific examples of structural unit (I). Can do.

［式（Ｉ’）中、Ｒ^１及びＡ^１は上記と同じ意味を表す。］ The structural unit (I) is derived from a compound represented by the formula (I ′) (hereinafter sometimes referred to as “compound (I ′)”).

[In formula (I ′), R ¹ and A ¹ represent the same meaning as described above. ]

式（Ｉ’−１−ａ）で表される化合物としては、メタクリル酸クロリドなどが挙げられる。このメタクリル酸クロリドは市場から容易に入手できる。 Compound (I ′) can be produced as follows.
Here, taking the compound (I ′) [compound represented by formula (I′-1)] wherein A ¹ is a single bond as an example, the production method thereof will be described.
The compound represented by the formula (I′-1) is obtained by combining the compound represented by the formula (I′-1-a) with the compound represented by the formula (I′-1-b) in the presence of a base catalyst. Then, it can be obtained by reacting in a solvent. The base catalyst used here is preferably pyridine, and the solvent is preferably tetrahydrofuran.

Examples of the compound represented by the formula (I′-1-a) include methacrylic acid chloride. This methacrylic acid chloride is easily available from the market.

Specific examples of compound (I ′) are shown below.

Regarding the compounds represented by the formulas (aa′-1) to (aa′-6), structural units in which the methyl group corresponding to R ¹ is replaced by a hydrogen atom are also exemplified as specific examples of the compound (I ′). Can do.

  As described above, the resin of the present invention has the structural unit (I). The content of the structural unit (I) in the resin is in the range of 1 to 100 mol%, preferably in the range of 2 to 70 mol%, with respect to the total structural units (100 mol%) of the resin. The range of -65 mol% is more preferable, and the range of 5-60 mol% is more preferable.

  The resist composition (particularly a chemically amplified resist composition) is insoluble or hardly soluble in an aqueous alkali solution and can be dissolved in an aqueous alkaline solution by the action of an acid (hereinafter, sometimes referred to as “acid action characteristics”). It is necessary to contain a resin having The resist composition of the present invention to be described later (hereinafter sometimes referred to as “the present resist composition”) may contain a resin having the structural unit (I) and a resin having acid action characteristics, It is preferable that the resin itself of the present invention has acid action characteristics. Among the resins of the present invention, those having acid action characteristics are hereinafter sometimes referred to as “resin (A)”. 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) can be produced by polymerizing a monomer having an acid labile group (hereinafter sometimes referred to as “monomer (a1)”) with the compound (I ′). 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. As the monomer (a1) for producing the resin (A), one type may be used alone, or two or more types may be used in combination.

<Monomer (a1)>
The “acid labile group” means a group that forms a hydrophilic group (for example, a hydroxy group, a carboxy group, etc.) by leaving the leaving group upon contact with an acid. Examples of such an acid labile group include a group represented by the formula (1) (hereinafter sometimes referred to as “acid labile group (1)”) and a group represented by the formula (2) ( Hereinafter, in some cases, it is referred to as “acid-labile group (2)”.

［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のアルキル基又は炭素数３〜２０の脂環式炭化水素基を表すか、Ｒ^a1及びＲ^a2は互いに結合して、それらが結合している炭素原子とともに、炭素数３〜２０の環を形成する。＊は結合手を表す。
］

［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、それらが結合する炭素原子及び酸素原子とともに、炭素数３〜２０の環を形成する。
該炭化水素基及び該環に含まれるメチレン基は、酸素原子又は硫黄原子に置き換わってもよい。］

[In Formula (1),
Or which R ^a1, R ^a2 and a R ^a3 (R ^a1 ~R ^a3) each independently represents an alicyclic hydrocarbon group of the alkyl group or 3 to 20 carbon atoms having 1 to 8 carbon atoms, R ^a1 and R ^a2 are bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. * Represents a bond.
]

[In Formula (2),
R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms, or R ^{a2 ′} and R ^{a2 ′} R ^{a3 ′} is bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom and the oxygen atom to which they are bonded.
The hydrocarbon group and the methylene group contained in the ring may be replaced with an oxygen atom or a sulfur atom. ]

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, and dimethylcyclohexane. Examples thereof include a cycloalkyl group such as a hexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic saturated hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, methylnorbornyl group, and the following groups. In the acid labile group (1), the alicyclic hydrocarbon group preferably has 3 to 16 carbon atoms.

When R ^a1 and R ^a2 are bonded to each other to form a ring, examples of the —C (R ^a1 ) (R ^a2 ) (R ^a3 ) group include the following groups. The number of carbon atoms in the ring 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 a tert-butoxycarbonyl group), 2- An alkyladamantan-2-yloxycarbonyl group (in the 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).

In the acid labile group (2), the hydrocarbon groups of R ^{a1 ′ to} R ^{a3 ′} may be, for example, any of an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Here, specific examples of the alkyl group and the alicyclic hydrocarbon group may be the same as the alkyl group and the alicyclic hydrocarbon group exemplified in R ^a1 of the formula (1), for example.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, and aryl groups such as 2-methyl-6-ethylphenyl.
Although the hydrocarbon groups R ^{a1 ′ to} R ^{a3 ′} have been described above, it is preferable that at least one of R ^{a1 ′} and R ^{a2 ′} is 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.

  Of the (meth) acrylic monomers having an acid labile group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferred. If the resin (A) obtained by polymerizing the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used, the resolution of the resist composition can be improved.

［式（ａ１−１）及び式（ａ１−２）中、
Ｌ^a1及びＬ^a2は、それぞれ独立に、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−を表し、ｋ１は１〜７の整数を表し、＊は−ＣＯ−との結合手を表す。
Ｒ^a4及びＲ^a5は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a6及びＲ^a7は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜１０の脂環式炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
ｎ１は０〜１０の整数を表す。
ｎ２は０又は１の整数を表す。］ The (meth) acrylic monomer having an acid labile group and an alicyclic hydrocarbon group is preferably a monomer (a1) represented by the formula (a1-1) and the formula (a1-2) [below] In some cases, these are referred to as “monomer (a1-1)” and “monomer (a1-2)” according to the formula number. ]. In producing the resin (A), these may be used alone or in combination of two or more.

[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents a bond to —CO—. Represents a hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms.
m1 represents the integer of 0-14.
n1 represents an integer of 0 to 10.
n2 represents an integer of 0 or 1. ]

ｍ１は、好ましくは０〜３の整数、より好ましくは０又は１である。
ｎ１は、好ましくは０〜３の整数、より好ましくは０又は１である。 L ^a1 and L ^a2 are preferably —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, more preferably —O—. k1 is preferably an integer of 1 to 4, more preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
Specific examples of the alkyl group for R ^a6 and R ^a7 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. The alkyl group for R ^a6 and R ^a7 preferably has 6 or less carbon atoms. The alicyclic hydrocarbon group preferably has 8 or less carbon atoms, more preferably 6 or less.
The alicyclic hydrocarbon group for R ^a6 and R ^a7 may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, Examples thereof include cycloalkyl groups such as methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, and cyclooctyl group. Examples of the polycyclic saturated hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, a methylnorbornyl group, and the following groups.

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.

As a monomer (a1-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, monomers (a1-1) represented by the following formulas (a1-1-1) to (a1-1-6) are preferable, and the following formulas (a1-1-1) to (a1-1-3) are preferable. And the monomer (a1-1) represented by each is more preferable.

Examples of the monomer (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, and 1-ethylcycloheptan-1-yl (meth). Examples include acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, and 1-isopropylcyclopentan-1-yl (meth) acrylate. Monomers (a1-2) represented by the following formulas (a1-2-1) to (a1-2-6) are preferable, and the following formulas (a1-2-3) to (a1-2-4) are respectively used. The monomer (a1-2) represented is more preferable, and the monomer (a1-2) represented by the following formula (a1-2-3) is more preferable.

  The content ratio of the structural unit derived from the monomer (a1-1) and / or the monomer (a1-2) in the resin (A) is usually in the range of 10 to 95 mol% with respect to all the structural units of the resin (A). Preferably, it is the range of 15-90 mol%, More preferably, it is the range of 20-85 mol%.

  The resin (A) can be preferably obtained by polymerizing the compound (I ′) and the monomer (a1), but in addition to the compound (I ′) and the monomer (a1), an acid labile group is added. More preferably, it is a copolymer obtained by polymerizing a monomer that is not present (hereinafter, sometimes referred to as “acid-stable monomer”). An acid stable monomer may be used individually by 1 type, and may use 2 or more types together.

  When the resin (A) is a copolymer of the compound (I ′), a monomer (a1) having an acid labile group and an acid stable monomer, the structural unit (I) is 100 mol% of all structural units. The amount is preferably in the range of 5 to 60 mol%, more preferably in the range of 10 to 50 mol%. The structural unit derived from the monomer (a1) is preferably in the range of 10 to 80 mol%, more preferably in the range of 20 to 60 mol% with respect to the total structural units. Moreover, the content rate of the structural unit derived from the monomer which has an adamantyl group (especially monomer (a1-1)), Preferably, it is 15 mol% or more with respect to the total amount of the structural unit derived from the monomer (a1). . When the content ratio of the structural unit derived from the monomer (a1) having an adamantyl group is increased, the dry etching resistance of the resist pattern obtained from the present resist composition containing the resin (A) is improved.

  As an acid stable monomer, Preferably, the monomer which has a hydroxyl group or a lactone ring is mentioned. Derived from an acid-stable monomer having a hydroxy group (hereinafter, sometimes referred to as “acid-stable monomer (a2)”) or an acid-stable monomer containing a lactone ring (hereinafter, sometimes referred to as “acid-stable monomer (a3)”). The present resist composition containing the resin (A) having a structural unit is superior in resolution, and in the production of a resist pattern described later, the composition layer formed on the substrate is excellent between the substrate and the substrate. There is a tendency to develop adhesion.

<Acid stable monomer (a2)>
When the acid-stable monomer (a2) is used for the production of the resin (A), a suitable acid-stable monomer (depending on the type of exposure source used when producing a resist pattern from the resist composition containing the resin (A), 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 monomer (a2 ), It is preferable to use an acid stable monomer having a phenolic hydroxyl group and represented by the formula (a2-0) described later for the production of the resin (A). When using exposure using a short wavelength ArF excimer laser (wavelength: 193 nm) as an exposure source, the acid stable monomer (a2) represented by the formula (a2-1) described below is used as the resin as the acid stable monomer (a2). (A) It is preferable to use for manufacture. Thus, the acid stable monomer (a2) used for the production of the resin (A) can be selected according to the exposure source used for producing the resist pattern. In addition, when using an acid stable monomer (a2) for resin (A) manufacture, this acid stable monomer (a2) may be used individually by 1 type, and may use 2 or more types together.

［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は同一であっても異なってもよい。］ As the acid-stable monomer (a2) having a phenolic hydroxy group, a styrene-based monomer such as p- or m-hydroxystyrene represented by the formula (a2-0) (hereinafter sometimes referred to as “acid-stable monomer (a2-0)”) ").

[In the 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 which may have a halogen atom in R ^a30 are the same as those exemplified as the alkyl group which may have a halogen atom of R ^{1 in} the formula (I). R ^a30 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.
As the alkyl group for R ^a31 , an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group and an ethyl group are more preferable, and a methyl group is particularly preferable.
Examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentoxy group, and n-hexoxy group. , Preferably, it is a C1-C4 alkoxy group, More preferably, they are a methoxy group and an ethoxy group, Most preferably, it is a methoxy group.
ma is preferably 0 to 2, more preferably 0 or 1, and particularly preferably 0.

  When obtaining a resin (A) having a structural unit derived from such an acid-stable monomer (a2-0), the phenolic hydroxyl group contained in the acid-stable monomer (a2-0) was protected with an appropriate protecting group. A monomer (protected acid stable monomer (a2-0)) may be used. If the resin having a structural unit derived from the protected acid-stable monomer (a2-0) is appropriately deprotected according to the type of the protecting group, the structure derived from the acid-stable monomer (a2-0) A resin having a unit can be obtained.

As an acid stable monomer (a2-0), the monomer described in Unexamined-Japanese-Patent No. 2010-204634 is mentioned, for example. Monomers represented by the following formulas (a2-0-1) and (a2-0-2) are preferable. When manufacturing resin (A), as mentioned above, what protected the phenolic hydroxy group with the appropriate protective group can also be used.

  When the resin (A) has a structural unit derived from the acid-stable monomer (a2-0), the content ratio is usually in the range of 5 to 90 mol% with respect to all the structural units of the resin (A). Yes, preferably in the range of 10-85 mol%, more preferably in the range of 15-80 mol%.

式（ａ２−１）中、
Ｌ^a3は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k2−ＣＯ−Ｏ−を表し、
ｋ２は１〜７の整数を表す。＊は−ＣＯ−との結合手を表す。
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。 Examples of the acid-stable monomer having a hydroxyadamantyl group include a monomer represented by the formula (a2-1) (hereinafter sometimes referred to as “acid-stable monomer (a2-1)”).

In formula (a2-1),
L ^a3 represents —O— or ^* —O— (CH ₂ ) _k2 —CO—O—,
k2 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents an integer of 0 to 10.

In the formula (a2-1), L ^a3 is preferably, -O-, k2 is a _{1~4 -O- (CH 2) k2 -CO} -O- and, more preferably -O- .
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

As an acid stable monomer (a2-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, monomers represented by the following formulas (a2-1-1) to (a2-1-6) are preferable, and represented by the following formulas (a2-1-1) to (a2-1-4), respectively. Monomers are more preferred, and monomers represented by the following formulas (a2-1-1) and (a2-1-3) are more preferred.

  When the resin (A) has a structural unit derived from the acid-stable monomer (a2-1), the content ratio is usually in the range of 3 to 45 mol% with respect to all the structural units of the resin (A). Yes, preferably in the range of 5-40 mol%, more preferably in the range of 5-35 mol%.

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

式（ａ３−１）〜式（ａ３−３）中、
Ｌ^a4〜Ｌ^a6は、それぞれ独立に、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−を表す。
ｋ３は１〜７の整数を表す。＊は−ＣＯ−との結合手を表す。
Ｒ^a18〜Ｒ^a20は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a21は、炭素数１〜４のアルキル基を表す。
ｐ１は０〜５の整数を表す。
Ｒ^a22及びＲ^a23は、それぞれ独立に、カルボキシ基、シアノ基又は炭素数１〜４のアルキル基を表す。
ｑ１及びｒ１は、それぞれ独立に０〜３の整数を表す。ｐ１が２以上のとき、複数のＲ^a21は互いに同一でも異なってもよく、ｑ１が２以上のとき、複数Ｒ^a22は互いに同一でも異なってもよく、ｒ１が２以上のとき、複数のＲ^a23は互いに同一でも異なってもよい。 The acid stable monomer (a3) is preferably represented by the formula (a3-1), the formula (a3-2) or the formula (a3-3). These 1 type may be used independently and may use 2 or more types together.

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

In the formula (a3-1) to the formula (a3-3), examples of L ^{a4 to} L ^a6 include those described for L ^a3 .
L ^{a4 to} L ^a6 are each independently preferably —O— or ^* —O— (CH ₂ ) _k3 —CO—O—, wherein k3 is an integer of 1 to 4, more preferably ^* —. O—CH ₂ —CO—O— and —O— are preferable, and —O— 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 to r1 are each independently preferably 0 to 2, more preferably 0 or 1.

Examples of the acid stable monomer (a3) include monomers described in JP 2010-204646 A. In the following formulas (a3-1-1) to (a3-1-4), (a3-2-1) to (a3-2-4), (a3-3-1) to (a3-3-4) The acid-stable monomer (a3) represented is preferable, and the acid represented by the following formulas (a3-1-1) to (a3-1-2), (a3-2-3) to (a3-2-4) The stable monomer (a3) is more preferable, and the acid stable monomer (a3) represented by the following formula (a3-1-1) or (a3-2-3) is more preferable.

  When the resin (A) has a structural unit derived from the acid-stable monomer (a3), the content ratio is usually in the range of 5 to 70 mol% with respect to all the structural units of the resin (A), Preferably it is the range of 10-65 mol%, More preferably, it is the range of 10-60 mol%.

<Other monomers>
The resin of the present invention, particularly the resin (A), may have a structural unit derived from the monomer (A1), the monomer (a1), and other monomers other than the acid-stable monomer described above. Examples of such other monomers include those known for the production of resins for resist compositions.

  Preferably, the resin (A) is produced from at least the compound (I ′) and the monomer (a1), and preferably the compound (I ′), the monomer (a1), and the acid stable monomer. It is manufactured from. As the acid stable monomer, the acid stable monomer (a2) and / or acid stable monomer (a3) described above are preferable. In the resin (A), the monomer (a1) is more preferably at least one of the monomer (a1-1) and the monomer (a1-2) (more preferably the monomer (a1-1)), and the acid stable monomer. (A2) is preferably an acid stable monomer (a2-1), and the acid stable monomer (a3) is more preferably an acid stable monomer represented by the formula (a3-1) having a γ-butyrolactone ring and It is at least one acid-stable monomer represented by the formula (a3-2) having a condensed ring of γ-butyrolactone ring and norbornane ring. The resin (A) can be produced by subjecting these monomers to a known polymerization method (for example, radical polymerization method).

  The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less). The weight average molecular weight is obtained as a polystyrene equivalent value by gel permeation chromatography, and details of the analysis conditions are described in the examples of the present application.

In the resist composition of the present invention to be described later (hereinafter sometimes referred to as “the present resist composition”), the content ratio of the resin (A) is preferably 80% by mass or more in the solid content of the resist composition. .
In the present specification, the “solid content in the composition” means the total of resist composition components excluding the solvent (D) described later. The solid content in the composition and the content ratio of the resin (A) to the solid content can be measured by a known analysis means such as liquid chromatography or gas chromatography.

A specific example of the resin (A) is shown as a combination of structural units as follows.

<This resist composition>
The resist composition contains the resin of the present invention (resin having the structural unit (I)), preferably the resin (A) (resin (A) having the structural unit (I)), so that the line edge roughness ( A resist pattern excellent in (LER) can be manufactured. In addition to the resin of the present invention, the present resist composition contains an acid generator (hereinafter sometimes referred to as “acid generator (B)”), and further a solvent (hereinafter sometimes referred to as “solvent (D)”). ), And a basic compound (hereinafter sometimes referred to as “basic compound (C)”). Hereinafter, the components contained in the resist composition will be described.

<Acid generator (B)>
Acid generators used in the resist field are classified into nonionic and ionic. The acid generator (B) contained in the resist composition may be a nonionic acid generator, an ionic acid generator, or a combination thereof. Nonionic acid generators include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone). 4-sulfonate), sulfones (for example, disulfone, ketosulfone, sulfonyldiazomethane) and the like. The ionic acid generator is typically an onium salt containing an onium cation (for example, diazonium salt, phosphonium salt, sulfonium salt, iodonium salt). Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

  Examples of the acid generator (B) include JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, and JP-A-63-163452. JP-A-62-153853, JP-A-63-146029, US Pat. No. 3,779,778, US Pat. No. 3,849,137, German Patent 3914407, European Patent 126, A compound capable of generating an acid by radiation described in No. 712 may also be used.

［式（Ｂ１）中、
Ｑ¹及びＱ²は、それぞれ独立に、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^b1は、単結合又は炭素数１〜１７の２価の飽和炭化水素基を表し、前記２価の飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｙは、置換基を有していてもよい炭素数１〜１８のアルキル基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、前記アルキル基及び前記脂環式炭化水素基に含まれるメチレン基は、酸素原子、スルホニル基又はカルボニル基に置き換わっていてもよい。
Ｚ⁺は、有機カチオンを表す。］
以下の説明において、酸発生剤（Ｂ１）から、有機カチオン（Ｚ⁺）を取り除いたものを、「スルホン酸アニオン」ということがある。 The acid generator (B) is preferably a fluorine-containing acid generator, and more preferably a sulfonate represented by the formula (B1) (hereinafter sometimes referred to as “acid generator (B1)”). .

[In the formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group contained in the divalent saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y represents an alkyl group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and the alkyl group and the above The methylene group contained in the alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Z ⁺ represents an organic cation. ]
In the following description, what remove | excluded the organic cation (Z ^<+> ) from the acid generator (B1) may be called "sulfonate anion."

Examples of the perfluoroalkyl group 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. Can be mentioned.
In formula (B1), Q ¹ and Q ² are each independently preferably a trifluoromethyl group or a fluorine atom, more preferably a fluorine atom.

Examples of the divalent saturated hydrocarbon group include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic hydrocarbon group, and 2 of these groups. It may be a combination of more than one species.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1 , 6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group , Dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1, Linear alkanediyl groups such as 17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-2,2-diyl group;
An alkyl group (particularly an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group) For example, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl Groups, branched alkanediyl groups such as 2-methylbutane-1,4-diyl group;
Cycloalkanediyl groups such as cyclobutane-1,3-diyl group, 1,3-cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group silene group, cyclooctane-1,5-diyl group, etc. A monocyclic divalent alicyclic hydrocarbon group which is a cycloalkanediyl group of
Norbornane-2,3-diyl group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,2-diyl group, adamantane-1,5-diyl group, adamantane-2,6 -Polycyclic bivalent alicyclic hydrocarbon groups, such as a diyl group, etc. are mentioned.

式（ｂ１−１）〜式（ｂ１−６）中、
Ｌ^b2は、単結合又は炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b3は、単結合又は炭素数１〜１２の２価の飽和炭化水素基を表す。
Ｌ^b4は、炭素数１〜１３の２価の飽和炭化水素基を表す。但しＬ^b3及びＬ^b4の炭素数上限は１３である。
Ｌ^b5は、炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b6及びＬ^b7は、それぞれ独立に、炭素数１〜１５の２価の飽和炭化水素基を表す。但しＬ^b6及びＬ^b7の炭素数上限は１６である。
Ｌ^b8は、炭素数１〜１４の２価の飽和炭化水素基を表す。
Ｌ^b9及びＬ^b10は、それぞれ独立に、炭素数１〜１１の２価の飽和炭化水素基を表す。
但しＬ^ｂ９及びＬ^ｂ１０の炭素数上限は１２である。
中でも、Ｌ^b1は式（ｂ１−１）で表される２価の基であると好ましく、Ｌ^b2は単結合又はメチレン基であると好ましい。 Examples of the group in which the methylene group contained in the saturated hydrocarbon group in L ^b1 is replaced with an oxygen atom or a carbonyl group include, for example, divalent groups represented by formulas (b1-1) to (b1-6), respectively. Groups. L ^b1 is preferably a divalent group represented by formula (b1-1) to formula (b1-4), more preferably represented by formula (b1-1) or formula (b1-2). A divalent group. In addition, in the formula (b1-1) to the formula (b1-6), the left and right are described in accordance with the formula (B1), and bonded to the carbon atom of —C (Q ¹ ) (Q ² ) — on the left side. And bind to -Y on the right. The same applies to specific examples of the following formulas (b1-1) to (b1-6).

In formula (b1-1) to formula (b1-6),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms. However, the upper limit of the carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 and L ^b7 each independently represent a divalent saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the carbon number of L ^b6 and L ^b7 is 16.
L ^b8 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 and L ^b10 each independently represent a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
However, the upper limit of the carbon number of L ^b9 and L ^b10 is 12.
Among these, L ^b1 is preferably a divalent group represented by the formula (b1-1), and L ^b2 is preferably a single bond or a methylene group.

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

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

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

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

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

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

As an alkyl group of Y, Preferably, a C1-C6 alkyl group is mentioned.
Examples of the substituent of the alkyl group and the alicyclic hydrocarbon group include a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, a hydroxy group-containing alkyl group having 1 to 12 carbon atoms, and 3 to 16 carbon atoms. An alicyclic hydrocarbon group, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group, or — (CH ₂ ) _j2 —O—CO—R ^b1 group (wherein R ^b1 is an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, or a group having 6 to 18 carbon atoms. Represents an aromatic hydrocarbon group, j2 represents an integer of 0 to 4, and the like. The alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, aralkyl group, and the like, which are substituents for Y, may further have a substituent. Examples of the substituent include an alkyl group, a halogen atom, a hydroxy group, and an oxo group.
Examples of the hydroxy group-containing alkyl group include a hydroxymethyl group and a hydroxyethyl group.
Examples of the group in which the methylene group in the alkyl group and the alicyclic hydrocarbon group of Y is replaced with an oxygen atom, a sulfonyl group or a carbonyl group include, for example, a cyclic ether group (a group in which a methylene group is replaced with an oxygen atom), oxo Group having an alicyclic hydrocarbon group (a group in which a methylene group is replaced with a carbonyl group), a sultone ring group (a group in which two adjacent methylene groups are replaced with an oxygen atom and a sulfonyl group, respectively) or a lactone ring group (Groups in which two adjacent methylene groups are replaced by an oxygen atom and a carbonyl group, respectively).

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

  Among them, preferred are groups represented by formula (Y1) to formula (Y19), and more preferred are groups represented by formula (Y11), formula (Y14), formula (Y15), or formula (Y19). And more preferably a group represented by the formula (Y11) or the formula (Y14).

Examples of Y that is an alicyclic hydrocarbon group having a substituent include the following.

  Y is preferably an adamantyl group which may have a substituent, and more preferably an adamantyl group or an oxoadamantyl group.

The sulfonate anion constituting the acid generator (B1) is preferably an anion represented by each of the formulas (b1-1-1) to (b1-1-1-9). In the following formulae, the definition of the substituent has the same meaning as described above, and the substituents R ^b2 and R ^b3 each independently represent an alkyl group having 1 to 4 carbon atoms (preferably a methyl group).
Specific examples of the sulfonic acid anion constituting the acid generator (B1) include anions described in JP 2010-204646 A.

以下、ここに示すスルホン酸アニオンをその式番号に応じて、「アニオン（ｂ１−１−１）」〜「アニオン（ｂ１−１−９）」という。

Hereinafter, the sulfonate anion shown here is referred to as “anion (b1-1-1)” to “anion (b1-1-9)” depending on the formula number.

  Examples of the organic cation constituting the acid generator (B1) include organic onium cations such as organic sulfonium cation, organic iodonium cation, organic ammonium cation, benzothiazolium cation, and organic phosphonium cation, and preferably organic sulfonium. It is a cation or an organic iodonium cation, and more preferably an arylsulfonium cation.

以下、ここに示す有機カチオンをその式番号に応じて、「カチオン（ｂ２−１）」〜「カチオン（ｂ２−４）」という。 The organic cation (Z ⁺ ) is preferably represented by any one of formulas (b2-1) to (b2-4).

Hereinafter, the organic cation shown here is referred to as “cation (b2-1)” to “cation (b2-4)” according to the formula number.

In these formulas (b2-1) to (b2-4),
R ^{b4 to} R ^b6 each independently represents an alkyl 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 alkyl group may be substituted with 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 has a halogen atom or a carbon number. The aromatic hydrocarbon group may be substituted with 2 to 4 acyl groups or glycidyloxy groups, and the aromatic hydrocarbon group is a halogen atom, a hydroxy group, an alkyl group having 1 to 18 carbon atoms, or an alicyclic group having 3 to 18 carbon atoms. It may be substituted with a hydrocarbon group or an alkoxy group having 1 to 12 carbon atoms.

R ^b7 and R ^b8 each independently represent a hydroxy group, an alkyl 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.

R ^b9 and R ^b10 each independently represent an alkyl group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms.
R ^b11 represents a hydrogen atom, an alkyl 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.
The alkyl group of R ^{b9 to} R ^b11 preferably has 1 to 12 carbon atoms, and the alicyclic hydrocarbon group preferably has 3 to 18 carbon atoms, more preferably 4 to 12 carbon atoms.
R ^b12 represents an alkyl 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. The aromatic hydrocarbon group is an alkyl 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 1 to 12 carbon atoms. May be substituted.
R ^b9 and R ^b10 , and R ^b11 and R ^b12 may be independently bonded to each other to form a 3- to 12-membered ring (preferably a 3- to 7-membered ring), The methylene group contained in these rings 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 alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b11 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When any of o2 to t2 is 2, any of the plurality of R ^{b13 to} R ^b18 may be the same as or different from each other.

  Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group, and a 2-ethylhexylcarbonyloxy group.

The alkyl group is preferably a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group and 2-ethylhexyl group. Is mentioned.
The alicyclic hydrocarbon group is preferably a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclodecyl group, a 2-alkyladamantan-2-yl group, or 1- (adamantan-1-yl). ) Alkane-1-yl group and isobornyl group.
The aromatic hydrocarbon group is preferably a phenyl group, a 4-methylphenyl group, a 4-ethylphenyl group, a 4-tert-butylphenyl group, a 4-cyclohexylphenyl group, a 4-methoxyphenyl group, or a biphenylyl group. And a naphthyl group.
Examples of the alkyl group (aralkyl group) whose substituent is an aromatic hydrocarbon group include a benzyl group.
Examples of the ring formed by R ^b9 and R ^b10 include a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring.
^Examples of the ring formed by R ^b11 and R ^b12 include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

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

式（ｂ２−１−１）中、
Ｒ^b19〜Ｒ^b21は、それぞれ独立に、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のアルキル基、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す。
アルキル基は、好ましくは炭素数１〜１２であり、脂環式炭化水素基は、好ましくは炭素数４〜１８である。
該アルキル基は、ヒドロキシ基、炭素数１〜１２のアルコキシ基又は炭素数６〜１８の芳香族炭化水素基で置換されていてもよい。
該脂環式炭化水素基は、ハロゲン原子、炭素数２〜４のアシル基又はグリシジルオキシ基で置換されていてもよい。
ｖ２、ｗ２及びｘ２（ｖ２〜ｘ２）は、それぞれ独立に０〜５の整数（好ましくは０又は１）を表す。ｖ２〜ｘ２のいずれかが２以上のとき、それぞれ、複数のＲ^b19〜Ｒ^b21のいずれかは、互いに同一でも異なってもよい。
なかでも、Ｒ^b19〜Ｒ^b21は、それぞれ独立に、好ましくは、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１〜１２のアルキル基、又は炭素数１〜１２のアルコキシ基である。

In formula (b2-1-1),
R ^{b19 to} R ^b21 each independently represent a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or 1 to 1 carbon atoms. 12 alkoxy groups are represented.
The alkyl group preferably has 1 to 12 carbon atoms, and the alicyclic hydrocarbon group preferably has 4 to 18 carbon atoms.
The alkyl group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
The alicyclic hydrocarbon group may be substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group.
v2, w2 and x2 (v2 to x2) each independently represent an integer of 0 to 5 (preferably 0 or 1). When any one of v2 to x2 is 2 or more, any one of the plurality of R ^{b19 to} R ^b21 may be the same as or different from each other.
Among them, R ^{b19 to} R ^b21 are preferably each independently 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. .

Specific examples of the organic cation (Z ⁺ ) include cations described in JP 2010-204646 A.

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

  As an acid generator (B1), Preferably, the salt respectively represented by Formula (B1-1)-Formula (B1-17) is mentioned, More preferably, a triphenylsulfonium cation or a tolylsulfonium cation is included. Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), Formula (B1-7), Formula (B1-11), Formula (B) that are acid generators B1-12), salts represented by formula (B1-13) and formula (B1-14), respectively.

  The content ratio of the acid generator (B) in the resist composition is expressed as a content ratio with respect to the content mass of the resin (A), and is preferably 1% by mass or more (more preferably 3% by mass or more), preferably 30% by mass. % Or less (more preferably 25% by mass or less).

<Basic compound (C)>
The resist composition preferably contains a basic compound (C). The basic compound (C) acts as a quencher.

  The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines. The basic compound (C) is preferably a compound represented by the formula (C1) to a compound represented by the formula (C8), more preferably a compound represented by the formula (C1-1). It is done.

［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、上記と同じ意味を表す。
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 represent the same meaning as described above.
R ^c4 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
m3 represents an integer of 0 to 3, and when m3 is 2 or more, 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と同じ意味を表す。
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 each independently represent the same meaning as R ^c1 .
R ^c9 represents an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 6 carbon atoms, or an alkanoyl group having 2 to 6 carbon atoms.
n3 represents an integer of 0 to 8, and when n3 is 2 or more, the plurality of R ^c9 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と同じ意味を表す。
Ｒ^c14、Ｒ^c15及びＲ^c17は、それぞれ独立に、Ｒ^c4と同じ意味を表す。
ｏ３及びｐ３は、それぞれ独立に０〜３の整数を表し、ｏ３又はｐ３が２以上であるとき、それぞれ、複数のＲ^c14及び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 each independently represent the same meaning as R ^c1 .
R ^c14 , R ^c15 and R ^c17 each independently represent the same meaning as R ^c4 .
o3 and p3 each independently represent an integer of 0 to 3, and when o3 or p3 is 2 or more, the plurality of R ^c14 and 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と同じ意味を表す。
ｑ３、ｒ３及びｓ３は、それぞれ独立に０〜３の整数を表し、ｑ３、ｒ３及びｓ３が２以上であるとき、それぞれ、複数のＲ^c18、Ｒ^c19及び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。］

Wherein (C7) and formula ^{(C8), R c18, R} c19 and R ^c20 in each occurrence independently represent the same meaning as R ^c4.
q3, r3 and s3 each independently represent an integer of 0 to 3, q3, when r3 and s3 is 2 or more, each of a plurality of R ^c18, R ^c19 and R ^{c 20} may be the same or different from each other .
L ^c2 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

  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-diphenyl Examples include ethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and preferably diisopropyl. Piruanirin. Particularly preferred include 2,6-diisopropylaniline.

Examples of the compound represented by the formula (C2) include piperazine.
Examples of the compound represented by the formula (C3) include morpholine.
Examples of the compound represented by the formula (C4) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound represented by the formula (C5) include 2,2′-methylenebisaniline.
Examples of the compound represented by the formula (C6) include imidazole and 4-methylimidazole.
Examples of the compound represented by the formula (C7) include pyridine and 4-methylpyridine.
Examples of the compound represented by the formula (C8) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1, 2-di (4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide 4,4′-dipyridyl disulfide, 2,2′-dipyridylamine, 2,2′-dipiconylamine, bipyridine and the like.

  As ammonium salt, 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.

  The content ratio of the basic compound (C) in the resist composition is preferably about 0.01 to 5% by mass, more preferably 0.01 to 3% by mass, based on the solid content of the resist composition. And is particularly preferably about 0.01 to 1% by mass.

<Solvent (D)>
When using it for manufacture of the resist pattern mentioned later, it is preferable that this resist composition contains the solvent (D). The content of the solvent (D) is, for example, 90% by mass or more, preferably 92% by mass or more, more preferably 94% by mass or more, for example, 99.9% by mass or less, based on the total mass of the resist composition. , Preferably it is 99 mass% or less.
The content ratio of the solvent (D) can be measured by a known analysis means such as liquid chromatography or gas chromatography.

  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 components (hereinafter referred to as “other components (F)”)>
This resist composition may contain the other component (F) as needed. The component (F) is not particularly limited, and additives known in the resist field, for example, sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes and the like can be used.

<Preparation method of the present resist composition>
The present resist composition is obtained by mixing the resin of the present invention (preferably, the resin (A)), the acid generator (B) and the solvent (D), or
It can prepare by mixing resin (preferably resin (A)) of this invention, an acid generator (B), a basic compound (C), and a solvent (D). When the resin of the present invention does not have acid action characteristics, a resin having acid action characteristics may be mixed in addition to the resin of the present invention. In such mixing, the mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select an appropriate temperature range from the range of 10-40 degreeC according to the kind etc. of resin of this invention, the solubility with respect to solvents (D), such as the said resin. The mixing time may be selected according to the mixing temperature, but is preferably 0.5 to 24 hours. The mixing means is not particularly limited, and stirring and mixing can be used.

  As described above, after mixing the resin of the present invention, the acid generator (B) and the solvent (D), and each of the basic compound (C) or the component (F) used as necessary at a preferable content. The resist composition can be prepared by filtration using a filter having a pore size of about 0.01 to 0.2 μm.

<Method for producing resist pattern>
The method for producing a resist pattern using the resist composition is as follows:
(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,
(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 present resist composition coated on the substrate, that is, the coating film is dried, and the solvent [solvent (D)] is removed from the coating 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 the immersion exposure, for example, ultrapure water or the like is used as the immersion medium.
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 acid generator (B), preferably the acid generator (B1) contained in the composition layer generates an acid upon receiving exposure energy, and further acts by reacting with the generated acid. An acid labile group in a resin having an action characteristic (preferably a resin (A) having an acid action characteristic) generates a hydrophilic group by a deprotection reaction. As a result, the resin in the composition layer of the exposed portion is an alkali. It becomes soluble in an aqueous solution. On the other hand, since the exposure energy is not received in the unexposed area, the resin 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, and preferably the heated composition layer is developed with a developing device. The term “development” as used herein refers to removing the composition layer in the exposed area by dissolving it in the aqueous alkali solution by bringing the heated composition layer into contact with the aqueous alkali solution. Since the unexposed portion is insoluble or hardly soluble in the alkaline aqueous solution as described above, it remains on the substrate, and a resist pattern is produced on the substrate.
As the alkaline aqueous solution, those known in this technical field called “alkaline developer” can be used. Examples of the alkaline aqueous solution include an aqueous solution of tetramethylammonium hydroxide and an aqueous solution of (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline).

  After the development, it is preferable to perform a rinsing treatment with ultrapure water or the like, and to further remove moisture remaining on the substrate and the resist pattern.

<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. .

The present invention will be described more specifically with reference to examples. In the examples, “%” and “parts” representing the content or amount used are based on mass unless otherwise specified. The composition ratio of the resin (A) (copolymerization ratio of the structural unit derived from each monomer used for the production of the resin (A) to the resin (A)) is the amount of unreacted monomer in the reaction liquid after the polymerization is finished. It measured using the chromatography, and computed by calculating | requiring the monomer amount used for superposition | polymerization from the obtained result. The weight average molecular weight is a value determined by gel permeation chromatography. The analysis conditions for gel permeation chromatography are as follows.
Column: TSKgel Multipore HXL-M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

以下、これらのモノマーを、その符号に応じて、「モノマー（Ｍ−Ａ）」〜「モノマー（Ｍ−Ｊ）」という。 Synthesis of Resin (A) Compounds (monomers) used in the synthesis of resin (A) are shown below.

Hereinafter, these monomers are referred to as “monomer (MA)” to “monomer (M-J)” according to their symbols.

Example 1 [Synthesis of Resin A1]
As a monomer, a monomer (MG), a monomer (ME), a monomer (MB), a monomer (M-H), and a monomer (M-I) are used, and the molar ratio (monomer (MG) : Monomer (ME): monomer (MB): monomer (M-H): monomer (M-I)) were mixed so as to be 32: 7: 8: 43: 10. 1.5 mass times dioxane was added to make a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators are added to the solution, respectively, with respect to the total monomer amount, and these are heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained is again dissolved in dioxane, and a solution obtained by pouring the solution into a methanol / water mixed solvent is precipitated twice, and the resin is filtered twice to perform a reprecipitation operation twice. 2 × 10 ³ resin A1 (copolymer) was obtained with a yield of 78%. This resin A1 has the following structural units. The molar ratio of each structural unit is (u-G) :( u-E) :( u-B) :( u-H) :( u-I) [structural unit derived from monomer (MA). , According to the sign of “A”. This is expressed as “(u−A)”. Structural units derived from other monomers are also shown in accordance with the symbols of the monomers. ] = 26.8: 7.0: 8.6: 47.2: 10.4.

Example 2 [Synthesis of Resin A2]
As a monomer, a monomer (MF), a monomer (ME), a monomer (MB), a monomer (M-H), and a monomer (M-I) are used, and the molar ratio (monomer (MF)) : Monomer (ME): monomer (MB): monomer (M-H): monomer (M-I)) were mixed so that the ratio was 35: 10: 6: 37: 12. 1.5 mass times dioxane was added to make a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators are added to the solution, respectively, with respect to the total monomer amount, and these are heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained was dissolved again in dioxane, and the solution obtained by pouring the solution into a methanol / water mixed solvent was precipitated twice, and the reprecipitation operation of filtering the resin was performed twice, and the weight average molecular weight 6. 9 × 10 ³ resin A2 (copolymer) was obtained with a yield of 65%. This resin A2 has the following structural units. The molar ratio of each structural unit is (u-F) :( u-E) :( u-B) :( u-H) :( u-I) = 26.9: 10.3: 7.3: 42.9: 12.6.

Example 3 [Synthesis of Resin A3]
As a monomer, a monomer (MG), a monomer (ME), a monomer (MB), a monomer (MD), a monomer (M-H) and a monomer (M-I) are used, and the molar ratio thereof. (Monomer (MG): Monomer (ME): Monomer (MB): Monomer (MD): Monomer (M-H): Monomer (M-I))) is 32: 7: 8: It mixed so that it might become 10:33:10, and 1.5 mass times dioxane of the total monomer amount was added, and it was set as the solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators are added to the solution, respectively, with respect to the total monomer amount, and these are heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained is again dissolved in dioxane, and a solution obtained by pouring the solution into a methanol / water mixed solvent is precipitated twice, and the resin is filtered twice to perform a reprecipitation operation twice. 3 × 10 ³ resin A3 (copolymer) was obtained with a yield of 77%. This resin A3 has the following structural units. The molar ratio of each structural unit is (u−G) :( u−E) :( u−B) :( u−D) :( u−H) :( u−I) = 26.8: 7. It was 0: 8.6: 11.2: 36.1: 10.3.

Example 4 [Synthesis of Resin A4]
As the monomer, monomer (MA), monomer (MB) and monomer (MI) are used, and the molar ratio thereof (monomer (MA): monomer (MB): monomer (MI)) ) Was 40:20:40, and 1.5 mass times dioxane of the total monomer amount was added to obtain a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators are added to the solution, respectively, and heated at 78 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained was dissolved again in dioxane, and the solution obtained by pouring the solution into a methanol / water mixed solvent was precipitated twice, and the reprecipitation operation of filtering the resin was performed twice, and the weight average molecular weight 6. 6 × 10 ³ resin A4 (copolymer) was obtained in a yield of 82%. This resin A4 has the following structural units. The molar ratio of each structural unit was (u−A) :( u−B) :( u−I) = 43.8: 20.3: 39.9.

Example 5 [Synthesis of Resin A5]
As a monomer, a monomer (MG), a monomer (ME), a monomer (MB), a monomer (MD), a monomer (M-H) and a monomer (M-J) are used, and the molar ratio thereof. (Monomer (MG): monomer (ME): monomer (MB): monomer (MD): monomer (M-H): monomer (M-J)) is 32: 7: 8: It mixed so that it might become 10:33:10, and 1.5 mass times dioxane of the total monomer amount was added, and it was set as the solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators are added to the solution, respectively, with respect to the total monomer amount, and these are heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained is again dissolved in dioxane, and a solution obtained by pouring the solution into a methanol / water mixed solvent is precipitated twice, and the resin is filtered twice to perform a reprecipitation operation twice. 8 × 10 ³ resin A5 (copolymer) was obtained with a yield of 77%. This resin A5 has the following structural units. The molar ratio of each structural unit is (u−G) :( u−E) :( u−B) :( u−D) :( u−H) :( u−J) = 26.8: 7. It was 0: 8.5: 11.2: 36.0: 10.5.

Synthesis Example 1 [Synthesis of Resin H1]
As the monomer, monomer (MA), monomer (MB) and monomer (MI) are used, and the molar ratio thereof (monomer (MA): monomer (MB): monomer (MI)) ) Was 40:20:40, and 1.5 mass times dioxane of the total monomer amount was added to obtain a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators are added to the solution, respectively, and heated at 78 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained was dissolved again in dioxane, and the solution obtained by pouring the solution into a methanol / water mixed solvent was precipitated twice, and the reprecipitation operation of filtering the resin was performed twice, and the weight average molecular weight 6. 5 × 10 ³ resin H1 (copolymer) was obtained with a yield of 85%. This resin H1 has the following structural units. The molar ratio of each structural unit was (u−A) :( u−B) :( u−I) = 43.9: 20.5: 39.6.

Examples 6 to 10 and Comparative Example 1
<Preparation of resist composition>
Resin A1 to Resin A5 and Resin H1 obtained in Examples 1 to 5 and Synthesis Example 1;
Acid generator B1 shown below;
Basic compound C1 shown below;
Each was dissolved in the solvent shown below in parts by mass shown in Table 2, and further filtered through a fluororesin filter having a pore diameter of 0.2 μm to prepare a resist composition.

<Resin>
A1 to A5, H1: Resin A1 to Resin A5, Resin H1
<Acid generator>
B1:

<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

<Manufacture of resist pattern and its evaluation>
The resist compositions of Examples 6 to 10 and the resist composition of Comparative Example 1 were subjected to line edge roughness (LER) evaluation by immersion exposure as follows. Hereinafter, the resist composition and the resist composition of Comparative Example 1 may be collectively referred to as “resist composition”.

<Immersion exposure evaluation of resist composition>
In the following manner, the resist composition was subjected to immersion exposure and line edge roughness (LER) evaluation was performed.
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Co., Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 780 mm. 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.
After applying the resist composition, the obtained silicon wafer was pre-baked (PB) for 60 seconds at a temperature described in the “PB” column of Table 2 on a direct hot plate. Using the ArF excimer stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light] on the wafer on which the resist composition film is thus formed, the exposure amount is stepwise. The line and space pattern was subjected to immersion exposure. Note that ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking (PEB) was performed for 60 seconds on the hot plate at the temperature described in the “PEB” column of Table 2, and further with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed.

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

<Evaluation of line edge roughness (LER)>
The wall surface of the resist pattern after the lithography process is observed with a scanning electron microscope.
If it is less than 3.5 nm, ◎◎,
Those exceeding 3.5 nm and 4 nm or less
O exceeding 4 nm and 4.5 nm or less
What exceeded 4.5 nm was set as x.
The results are shown in Table 3.

  The resist compositions (Examples 6 to 10) were able to produce resist patterns with excellent line edge roughness. On the other hand, in the resist composition of Comparative Example 1, the line edge roughness of the resulting resist pattern was poor.

  The resist composition containing the resin of the present invention can produce a resist pattern having excellent line edge roughness (LER). Therefore, the present resist composition is extremely useful for fine processing of semiconductors, and the resin of the present invention that can realize such a resist composition has extremely high industrial value.

Claims (6)

A resin having a structural unit derived from an acid-stable monomer containing a structural unit represented by formula (I) and a lactone ring.

[In the formula (I),
R ¹ represents a C 1-6 alkyl group, a hydrogen atom or a halogen atom which may have a halogen atom.
A ¹ represents a single ^{bond, * - A 2 -O -,} * - A 2 -CO-O -, * - A 2 -CO-O-A 2 -CO-O- or ^* -A 2 -O-CO -A represents a ² -O-.
* Represents a bond with -O-.
A ² represents an alkanediyl group having 1 to 6 carbon atoms. ] A resist composition containing a resin having a structural unit represented by formula (I), an acid generator, and a solvent,
A resist composition, wherein the solvent comprises propylene glycol monomethyl ether.

[In the formula (I),
R ¹ represents a C 1-6 alkyl group, a hydrogen atom or a halogen atom which may have a halogen atom.
A ¹ represents a single ^{bond, * - A 2 -O -,} * - A 2 -CO-O -, * - A 2 -CO-O-A 2 -CO-O- or ^* -A 2 -O-CO -A represents a ² -O-.
* Represents a bond with -O-.
A ² represents an alkanediyl group having 1 to 6 carbon atoms. ] A resist composition containing a resin having a structural unit represented by formula (I), an acid generator, and a solvent,
A resist composition wherein the solvent contains 2-heptanone.

[In the formula (I),
R ¹ represents a C 1-6 alkyl group, a hydrogen atom or a halogen atom which may have a halogen atom.
A ¹ represents a single ^{bond, * - A 2 -O -,} * - A 2 -CO-O -, * - A 2 -CO-O-A 2 -CO-O- or ^* -A 2 -O-CO -A represents a ² -O-.
* Represents a bond with -O-.
A ² represents an alkanediyl group having 1 to 6 carbon atoms. ] A resist composition containing a resin having a structural unit represented by formula (I), an acid generator, and a solvent,
A resist composition, wherein the solvent comprises γ-butyrolactone.

[In the formula (I),
R ¹ represents a C 1-6 alkyl group, a hydrogen atom or a halogen atom which may have a halogen atom.
A ¹ represents a single ^{bond, * - A 2 -O -,} * - A 2 -CO-O -, * - A 2 -CO-O-A 2 -CO-O- or ^* -A 2 -O-CO -A represents a ² -O-.
* Represents a bond with -O-.
A ² represents an alkanediyl group having 1 to 6 carbon atoms. ]   The resist composition according to claim 2, wherein the solvent further contains propylene glycol monomethyl ether acetate.   The resist composition according to claim 1, wherein the resin is a resin that is insoluble or hardly soluble in an aqueous alkali solution and can be dissolved in the aqueous alkali solution by the action of an acid.