JP2007114261A - Resist composition and resist pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composition excellent in resolution and capable of forming a finer resist pattern, and a resist pattern forming method. <P>SOLUTION: The resist composition contains (A) a resin component the alkali solubility of which varies by the action of an acid and (B) an acid generator component capable of generating an acid upon exposure, wherein the component (B) contains a compound (B0) represented by formula (B-0) [wherein R<SP>0</SP>represents an alkyl group or an alkoxy group; X represents a halogenated alkyl group; (a) is an integer of 0-3; and when (a) is 2 or 3, a plurality of symbols R<SP>0</SP>may be the same or different]. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resist composition and a resist pattern forming method.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to light such as light or an electron beam through a mask on which a predetermined pattern is formed. And a development process is performed to form a resist pattern having a predetermined shape on the resist film. A resist material in which the exposed portion changes to a property that dissolves in the developer is referred to as a positive type, and a resist material that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type.
In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has been rapidly progressing due to advances in lithography technology.
As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but at present, mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. In addition, studies have been made on F ₂ excimer lasers, electron beams, EUV (extreme ultraviolet rays), X-rays, and the like having shorter wavelengths than these excimer lasers.

  Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions. As a resist material satisfying such requirements, a chemically amplified resist containing a base resin whose alkali solubility is changed by the action of an acid and an acid generator that generates an acid upon exposure is used.

Up to now, as the base resin of chemically amplified resist, polyhydroxystyrene (PHS), which is highly transparent to KrF excimer laser (248 nm), and a resin whose hydroxyl group is protected with an acid dissociable, dissolution inhibiting group (PHS resin) Has been used. However, since the PHS resin has an aromatic ring such as a benzene ring, the transparency to light having a wavelength shorter than 248 nm, for example, 193 nm, is not sufficient. Therefore, a chemically amplified resist having a PHS-based resin as a base resin component has drawbacks such as low resolution in a process using 193 nm light, for example. Therefore, as a resist base resin currently used in ArF excimer laser lithography and the like, since it has excellent transparency near 193 nm, a resin (acrylic resin) having a structural unit derived from (meth) acrylic ester is used. System resin) is mainly used (for example, see Patent Documents 1 and 2).
As the acid generator used for the chemically amplified resist, an onium salt acid generator having an onium ion such as a sulfonium ion or an iodonium ion in the cation portion is mainly used. Various acid generators have been proposed so far. For example, Patent Document 3 discloses an acid generator composed of a triphenylsulfonium-based onium salt.
The anion portion of the onium salt acid generator is generally an alkyl sulfonate ion or a fluorinated alkyl sulfonate ion in which part or all of the hydrogen atoms of the alkyl group are substituted with a fluorine atom. An onium salt acid generator having a fluorinated alkyl sulfonate ion in the anion portion, such as phenylsulfonium nonafluorobutane sulfonate (TPS-PFBS), is most used.

Non-patent documents 1 to 3 below describe a compound that is common to the compound (B0) in the present invention, but it does not describe the use of this compound as an acid generator in a chemically amplified resist composition. Absent.
Japanese Patent No. 2881969 JP 2003-241385 A JP 2003-167347 A Tetrahedron Lett. Vol. 33, NO. 5, pp. 607-608, 1992 Tetrahedron: Asymmetry, Vol. 4, NO. 11, pp. 2333-2334, 1993 Tetrahedron, Vol. 52, no. 44, pp. 14041-14048, 1996

In recent years, the miniaturization of resist patterns has further progressed, and improvement in resolution has been demanded. However, a resist composition using a conventional acid generator has insufficient resolution.
This invention is made | formed in view of the said situation, Comprising: It aims at providing the resist composition and resist pattern formation method excellent in resolution.

The present inventors propose the following means in order to solve the above problems.
That is, the first aspect of the present invention is a resist composition comprising (A) a resin component whose alkali solubility is changed by the action of an acid, and (B) an acid generator component which generates an acid upon exposure, The component (B) contains a compound (B0) represented by the following general formula (B-0).

［前記式中、Ｒ^０はアルキル基又はアルコキシ基を表し；Ｘはハロゲン化アルキル基を表し；ａは０〜３の整数であり；ａが２または３のとき、Ｒ^０は互いに同じでもよく異なっていてもよい。］

[Wherein, R ⁰ represents an alkyl group or an alkoxy group; X represents a halogenated alkyl group; a is an integer of 0 to 3; and when a is 2 or 3, R ⁰ may be the same as each other. May be different. ]

  The second aspect of the present invention includes a step of forming a resist film on a substrate using the resist composition of the first aspect, a step of selectively exposing the resist film, and an alkali development of the resist film. And a resist pattern forming method including a step of forming a resist pattern.

In the present specification and claims, “structural unit” means a monomer unit (monomer unit) constituting a resin component (polymer).
Further, the “alkyl group” includes a linear, branched or cyclic monovalent saturated hydrocarbon group unless otherwise specified.
“Exposure” is a concept that includes general irradiation of radiation, and includes irradiation of an electron beam.

  ADVANTAGE OF THE INVENTION According to this invention, the resist composition and resist pattern formation method which can form the resist pattern excellent in resolution can be provided.

≪Resist composition≫
The resist composition of the present invention includes (A) a resin component whose alkali solubility is changed by the action of an acid, and (B) an acid generator component that generates an acid upon exposure. The resist composition of the present invention may be a positive resist composition or a negative resist composition.
The component (A) is not particularly limited, and the action of one or two or more (A _N ) alkali-soluble resins or (A _P ) acids that have been proposed as base resins for chemically amplified resists. Thus, a resin component whose alkali solubility is increased can be used. In the former case, a so-called negative type resist composition is used, and in the latter case, a so-called positive type resist composition.

In the case of the negative type, (C) a crosslinking agent is blended in the resist composition together with the (A _N ) alkali-soluble resin and the (B) component. When an acid is generated from the component (B) by exposure at the time of resist pattern formation, the acid acts to cause cross-linking between the alkali-soluble resin and the cross-linking agent, thereby changing to alkali-insoluble.

In the case of the positive type, the (A _P ) component is an alkali-insoluble one having a so-called acid dissociable, dissolution inhibiting group. By dissociating, the (A _P ) component becomes alkali-soluble.
Therefore, in the formation of the resist pattern, when the resist composition applied on the substrate is selectively exposed, the alkali solubility of the exposed portion increases and alkali development can be performed.

Hereinafter, preferred embodiments of the resist composition of the present invention will be described.
[First Embodiment]
The first embodiment of the resist composition of the present invention comprises (A _P ) an acid dissociable, dissolution inhibiting group, a resin component whose alkali solubility is increased by the action of an acid, and (B) an acid generated by exposure. A positive resist composition containing an acid generator component, wherein the (A _P ) component is a structural unit (a1) derived from hydroxystyrene and the following general formula (a2-1) or (a2-2): And a resin component (A _P 1) containing the structural unit (a2) represented by formula (B2), wherein the component (B) contains the compound (B0) represented by the general formula (B-0). It is a resist composition.

［式中、Ｚは炭素数１〜５のアルキル基または脂肪族環式基を表し；ｎは０〜３の整数を表し；ｍは０または１を表し；Ｒはそれぞれ独立して水素原子、アルキル基、ハロゲン原子またはハロゲン化アルキル基を表し；Ｒ^１、Ｒ^２はそれぞれ独立して水素原子または炭素数１〜５の低級アルキル基を表す。］

[In the formula, Z represents an alkyl group having 1 to 5 carbon atoms or an aliphatic cyclic group; n represents an integer of 0 to 3; m represents 0 or 1; and each R independently represents a hydrogen atom, Represents an alkyl group, a halogen atom or a halogenated alkyl group; R ¹ and R ² each independently represents a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms; ]

<Resin component (A _P 1)>
Structural unit (a1)
The structural unit (a1) is a structural unit derived from hydroxystyrene.
In this embodiment, by using the (A _P 1) component including the structural unit (a1) and the structural unit (a2), the exposure margin when forming the resist pattern can be further increased and the resolution can be improved. It can be improved further. Moreover, dry etching tolerance improves by having a structural unit (a1). Furthermore, there is an advantage that hydroxystyrene as a raw material is easily available and is inexpensive.
As used herein, “hydroxystyrene” refers to hydroxystyrene, and those obtained by substituting a hydrogen atom bonded to the α-position of hydroxystyrene with another substituent such as a halogen atom, an alkyl group, or a halogenated alkyl group, and derivatives thereof. The concept includes a hydroxystyrene derivative (monomer).
The “structural unit derived from hydroxystyrene” includes a structural unit obtained by cleaving an ethylenic double bond of hydroxystyrene and a hydroxystyrene derivative (monomer).
In the “hydroxystyrene derivative”, at least a benzene ring and a hydroxyl group bonded thereto are maintained. For example, a hydrogen atom bonded to the α-position of hydroxystyrene is a halogen atom, a lower alkyl group having 1 to 5 carbon atoms, Those substituted with other substituents such as a halogenated alkyl group, those having a lower alkyl group having 1 to 5 carbon atoms bonded to the benzene ring to which the hydroxyl group of hydroxystyrene is bonded, and this hydroxyl group bonded In addition, one having 1 to 2 hydroxyl groups bonded to a benzene ring (in this case, the total number of hydroxyl groups is 2 to 3) and the like are included.
Examples of the halogen atom include a chlorine atom, a fluorine atom, and a bromine atom, and a fluorine atom is preferable.
The “α-position of hydroxystyrene” means a carbon atom to which a benzene ring is bonded unless otherwise specified.
As a structural unit (a1) in this embodiment, the structural unit represented by the following general formula (a-1) can be illustrated.

［上記式中、Ｒは水素原子、アルキル基、ハロゲン原子またはハロゲン化アルキル基を表し；Ｒ^３は炭素数１〜５の低級アルキル基を表し；ｏは１〜３の整数を表し；ｐは０〜２の整数を表す。］

[In the above formula, R represents a hydrogen atom, an alkyl group, a halogen atom or a halogenated alkyl group; R ³ represents a lower alkyl group having 1 to 5 carbon atoms; o represents an integer of 1 to 3; An integer of 0 to 2 is represented. ]

The alkyl group of R is preferably a lower alkyl group, and is an alkyl group having 1 to 5 carbon atoms. Further, a linear or branched alkyl group is preferable, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. It is done. Of these, a methyl group is preferred industrially.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
The halogenated alkyl group is preferably a halogenated lower alkyl group, in which some or all of the hydrogen atoms of the above-described lower alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Especially, it is preferable that all the hydrogen atoms are fluorinated.
As the halogenated lower alkyl group, a linear or branched fluorinated lower alkyl group is preferable, and a trifluoromethyl group, a hexafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, and the like are more preferable. The group (—CF ₃ ) is most preferred.
R is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

Examples of the lower alkyl group having 1 to 5 carbon atoms of R ³ include those similar to the lower alkyl group having 1 to 5 carbon atoms of R.
o is an integer of 1 to 3, preferably 1. When o is 1, the position of the hydroxyl group may be any of the o-position, m-position and p-position, but the p-position is preferred because it is readily available and inexpensive. Furthermore, when o is 2 or 3, arbitrary substitution positions can be combined.
p is an integer of 0-2. Of these, p is preferably 0 or 1, and particularly preferably 0 industrially. When p is 1, the substitution position of R ³ may be any of the o-position, m-position, and p-position, and when p is 2, any substitution position is combined. Can do.

In the component (A _P 1), the proportion of the structural unit (a1) is preferably 10 to 80 mol%, more preferably 20 to 75, with respect to all the structural units constituting (A _P 1). -70 mol% is more preferable, and 50-65 mol% is the most preferable. Within this range, moderate alkali solubility is obtained, and the balance with other structural units is good.

Structural unit (a2)
The structural unit (a2) is a structural unit represented by the general formula (a2-1) or (a2-2). That is, the structural unit (a2) is a structural unit derived from acrylic acid, and an acetal group (alkoxyalkyl) is bonded to the terminal oxygen atom of the carbonyloxy group (—C (O) —O—) derived from the carboxy group. Group) type acid dissociable, dissolution inhibiting group [—C (R ¹ R ² ) —O— (CH ₂ ) _n —Z]. Therefore, when an acid acts, a bond is cut between the acid dissociable, dissolution inhibiting group and the terminal oxygen atom.
Therefore, the (A _P 1) component is insoluble in alkali before the acid is allowed to act, and when the acid is allowed to act, the above-described acid dissociable, dissolution inhibiting group is dissociated, whereby the entire (A _P 1) component is alkali-soluble. Can change to
In addition, the deprotection energy of such an acetal group (alkoxyalkyl group) type acid dissociable, dissolution inhibiting group is lower than that of a tertiary ester type acid dissociable, dissolution inhibiting group, and therefore has a structural unit (a2). Thus, even if the acid strength is weak, there is an advantage that the acid dissociable, dissolution inhibiting group can be eliminated, the alkali solubility can be increased, and a fine pattern can be resolved.

In this specification, “acrylic acid” refers to acrylic acid (CH ₂ ═CH—COOH) in which a hydrogen atom is bonded to the α-position carbon atom, and other hydrogen atoms bonded to the α-position carbon atom are substituted. The concept includes an α-substituted acrylic acid substituted with a group and an acrylic acid derivative such as the following acrylic ester. Examples of the substituent include a halogen atom, an alkyl group, and a halogenated alkyl group.
“Acrylic acid ester” is not only an acrylic acid ester in which a hydrogen atom is bonded to a carbon atom at the α-position, but also an α-substituted acrylic acid in which the hydrogen atom bonded to the carbon atom in the α-position is substituted with another substituent. The concept includes esters. Examples of the substituent include a halogen atom, an alkyl group, and a halogenated alkyl group.
In “acrylic acid” and “acrylic acid ester”, “α-position (α-position carbon atom)” means a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
“Structural unit derived from acrylic acid” means a structural unit formed by cleavage of an ethylenic double bond of acrylic acid.
“A structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
In acrylic acid and acrylic acid ester, the alkyl group as a substituent at the α-position is preferably a lower alkyl group having 1 to 5 carbon atoms. Specifically, lower linear or branched alkyl such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group and neopentyl group. Groups.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.

R in the general formulas (a2-1) and (a2-2) is the same as R in the general formula (a-1).
R ¹ and R ² are each independently a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms.
Specific examples of the lower alkyl group for R ¹ and R ² include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. And a lower linear or branched alkyl group. The lower alkyl group is preferably a methyl group or an ethyl group in terms of industrial availability. Since R ¹ and R ² are excellent in the effects of the present invention, at least one of them is preferably a hydrogen atom, and more preferably both are hydrogen atoms.
n is preferably an integer of 0 to 3, preferably 0 or 1, and most preferably 0.
m is 0 or 1, preferably 1.

Z represents an alkyl group having 1 to 5 carbon atoms or an aliphatic cyclic group, preferably an aliphatic cyclic group having 20 or less carbon atoms, and more preferably an aliphatic cyclic group having 5 to 12 carbon atoms.
Here, “aliphatic” in the present specification and claims is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity. The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity. The aliphatic cyclic group may be either saturated or unsaturated, but is usually preferably saturated.
The aliphatic cyclic group as Z may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, a hydrophilic group, and the like. Examples of the hydrophilic group include ═O, —COOR (R is an alkyl group), alcoholic hydroxyl group, —OR (R is an alkyl group), imino group, amino group, and the like. O or an alcoholic hydroxyl group is preferred.
The structure of the basic ring (basic ring) excluding the substituent in the aliphatic cyclic group may be a ring consisting of carbon and hydrogen (hydrocarbon ring), and the carbon atoms constituting the hydrocarbon ring A heterocyclic ring partially substituted with a hetero atom such as a sulfur atom, an oxygen atom, or a nitrogen atom may be used. For the effect of the present invention, the basic ring in the aliphatic cyclic group as Z is preferably a hydrocarbon ring.
The hydrocarbon ring can be appropriately selected and used from among many proposed KrF resists, ArF resists and the like. Specifically, monocycloalkane, bicycloalkane, tricycloalkane, tetracyclo Examples include polycycloalkanes such as alkanes. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, norbornene, methylnorbornane, ethylnorbornane, methylnorbornene, ethylnorbornene, isobornane, tricyclodecane, and tetracyclododecane. Among these, cyclohexane, cyclopentane, adamantane, norbornane, norbornene, methylnorbornane, ethylnorbornane, methylnorbornene, ethylnorbornene, and tetracyclododecane are industrially preferable, and adamantane is more preferable.

Examples of the acid dissociable, dissolution inhibiting group represented by the formula —C (R ¹ R ² ) —O— (CH ₂ ) _n —Z include groups represented by the following formulas (4) to (15). It is done.

  More specifically, the structural unit (a2) is represented by, for example, the following general formulas (a2-2-1) to (a2-2-21) and (a2-4-1) to (a2-4-30). The structural unit is given.

  In the present invention, it is particularly preferable that the structural unit (a2) has the structural unit (a2-1) because the effects of the present invention are excellent. Among them, Formula (a2-2-9), Formula (a2-2-10), Formula (a2-2-13), Formula (a2-2-14), Formula (a2-2-15), Formula (a2) The structural unit represented by -2-16) is preferable because the effect of the present invention is excellent.

In the component (A _P 1), the proportion of the structural unit (a2) is preferably from 5 to 50 mol%, more preferably from 10 to 40 mol%, based on all the structural units constituting the (A _P 1) component. More preferred is ~ 35 mol%. By setting it to the lower limit value or more, a pattern can be obtained when the resist composition is used, and by setting it to the upper limit value or less, the balance with other structural units is good. Moreover, it is excellent in an exposure margin by setting it as the said range.

Structural unit (a3)
In addition to the structural units (a1) and (a2), the (A _P 1) component may further have a structural unit (a3) derived from styrene.
In the present embodiment, the structural unit (a3) is not essential, but if it is contained, the solubility in the developer can be adjusted, and the exposure margin is further improved. In addition, advantages such as improved depth of focus and improved dry etching resistance can be obtained.
Here, the “structural unit derived from styrene” includes a structural unit obtained by cleaving an ethylenic double bond of styrene and a styrene derivative (not including hydroxystyrene).
“Styrene derivatives” are those in which the hydrogen atom bonded to the α-position of styrene is substituted with other substituents such as a halogen atom, an alkyl group, a halogenated alkyl group, and the hydrogen atom of the phenyl group of styrene. Those substituted with a substituent such as a lower alkyl group having 1 to 5 carbon atoms are included.
Examples of the halogen atom include a chlorine atom, a fluorine atom, and a bromine atom, and a fluorine atom is preferable.
The “α-position of styrene” means a carbon atom to which a benzene ring is bonded unless otherwise specified.
In the present embodiment, examples of the structural unit (a3) include structural units represented by the following general formula (a-3).

［式中、Ｒは水素原子、アルキル基、ハロゲン原子またはハロゲン化アルキル基を表し；Ｒ^３は炭素数１〜５の低級アルキル基を表し；ｎ’は０〜３の整数を表す。］

[Wherein, R represents a hydrogen atom, an alkyl group, a halogen atom or a halogenated alkyl group; R ³ represents a lower alkyl group having 1 to 5 carbon atoms; and n ′ represents an integer of 0 to 3. ]

Wherein (a-3), the same as R and ^{R 3} in the formula (a-1) can be mentioned as R and ^{R 3.}
n 'is an integer of 0-3. Of these, n ′ is preferably 0 or 1, and is particularly preferably 0 industrially. When n ′ is 1 to ³ , the substitution position of R ³ may be any of the o-position, m-position and p-position, and when n ′ is 2 or 3, it is optional. The substitution positions can be combined.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
When the component (A _P 1) has the structural unit (a3), the proportion of the structural unit (a3) is preferably 1 to 20 mol% with respect to all the structural units constituting the component (A _P 1). 15 mol% is more preferable and 5-15 mol% is further more preferable. Within this range, the effect of having the structural unit (a3) is high, and the balance with other structural units is also good.

In the present embodiment, the component (A _P 1) is preferably a copolymer having all of these structural units (a1) to (a3) from the viewpoint of the effect of the present embodiment, and particularly the structural unit (a1). ) To (a3).

Structural unit (a4)
The component (A _P 1) may contain other structural units (a4) other than the structural units (a1) to (a3) as long as the effects of the present invention are not impaired.
The structural unit (a4) is not particularly limited as long as it is another structural unit that is not classified into the structural units (a1) to (a3) described above. For ArF excimer laser, for KrF positive excimer laser (preferably ArF excimer) A number of hitherto known materials can be used for resist resins such as lasers.

The component (A _P 1) can be obtained by polymerizing a monomer that derives each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). it can.

The weight average molecular weight of the (A _P 1) component (polystyrene conversion by gel permeation chromatography (GPC), the same shall apply hereinafter) is preferably 3000 to 50000, more preferably 5000 to 30000, and even more preferably 5000 to 20000. When the mass average molecular weight is 50000 or less, sufficient solubility in a resist solvent can be secured, and roughness can be reduced. Moreover, it is easy to adjust the solubility with respect to a developing solution as it is 3000 or more. In addition, dry etching resistance is improved and film loss is improved.
Further, the smaller the degree of dispersion (Mw / Mn (number average molecular weight)) of the (A _P 1) component (the closer to monodispersion), the better the resolution and the better. The dispersity is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.0 to 2.5.

In the positive resist composition of this embodiment, the (A _P 1) component may be a single type or a combination of two or more types.
In the present embodiment, as the (A _P ) component, in addition to the (A _P 1) component, generally chemically amplified positive resists such as a PHS resin and an acrylic resin, as long as the effects of the present embodiment are not impaired. You may contain the resin currently used as resin for an application.
In the component (A _P ), the proportion of the component (A _P 1) is preferably 50% by mass or more, more preferably 80 to 100% by mass, and most preferably 100% by mass in terms of the effect of the present embodiment. It is.
In the positive resist composition of this embodiment, the content of the (A _P ) component may be adjusted according to the resist film thickness to be formed.

<Acid generator (B)>
(B) A component contains the compound (B0) represented by the said general formula (B-0).
In Formula (B-0), R ⁰ represents an alkyl group or an alkoxy group.
The alkyl group as R ⁰ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms. The alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms. Specific examples include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group and the like.
The alkoxy group as R ⁰ is preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. More preferably, the alkoxy group has 1 to 3 carbon atoms,
More preferably, it is 1-2. Specific examples include methoxy group, ethoxy group, propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, tert-butoxy group and the like.
Among these, R ⁰ is preferably a methyl group because it can be easily synthesized.

A in the formula (B-0) is an integer of 0 to 3. When a is 2 or 3, R ⁰ may be the same as or different from each other, but is more preferably the same as each other. a is more preferably 0 to 2, particularly preferably 1 or 2, and most preferably 2.

X in the formula (B-0) represents a halogenated alkyl group.
The halogenated alkyl group is a group in which some or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms, and since the effects of the present invention are excellent, all of the hydrogen atoms are substituted with halogen atoms. Is preferred.
Specifically, the alkyl group is a linear or branched alkyl group having 1 to 10 carbon atoms. The alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms. Specific examples include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group and the like. Among these, a methyl group is more preferable in terms of easy synthesis.
The halogen atom in the halogenated alkyl group is specifically a fluorine atom or a chlorine atom, and a fluorine atom is more preferable from the viewpoint of acid strength.

  Specific examples of the compound (B0) represented by the general formula (B-0) include the following chemical formulas (B-0-1) to (B-0-4).

  The compound (B0) represented by the general formula (B-0) can be produced, for example, based on the methods described in Non-Patent Documents 1 to 3.

The resist composition of the present embodiment may contain an acid generator (B1) other than the compound (B0) as long as the effects of the present invention are not impaired.
Other acid generators (B1) are not particularly limited, and various acid generators for chemically amplified resists have been proposed so far, and these can be used. Examples of such acid generators include conventionally known onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, poly (bissulfonyl) diazomethanes, and the like. And diazomethane acid generator, nitrobenzyl sulfonate acid generator, imino sulfonate acid generator, and disulfone acid generator.

The component (B) in the resist composition of the present embodiment may be used singly or in combination of two or more.
The content of the component (B) in the positive resist composition of the present invention is preferably 0.5 to 30 parts by mass, more preferably 1 to 20 parts by mass, with respect to 100 parts by mass of the component (A), and 3 to 15 Part by mass is most preferred. By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.
Further, the proportion of the compound (B0) in the whole component (B) is preferably 50% by mass or more, more preferably 70% by mass or more, and most preferably 100% by mass from the viewpoint of the effect of the present invention.

Hereinafter, specific examples of the other acid generator (B1) will be described.
As the onium salt-based acid generator as the component (B1), for example, an acid generator represented by the following general formula (b-0) can be preferably used.

［式中、Ｒ^５１は、直鎖、分岐鎖若しくは環状のアルキル基、または直鎖、分岐鎖若しくは環状のフッ素化アルキル基を表し；Ｒ^５２は、水素原子、水酸基、ハロゲン原子、直鎖若しくは分岐鎖状のアルキル基、直鎖若しくは分岐鎖状のハロゲン化アルキル基、または直鎖若しくは分岐鎖状のアルコキシ基であり；Ｒ^５３は置換基を有していてもよいアリール基であり；ｕ”は１〜３の整数である。］

[Wherein, R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic fluorinated alkyl group; R ⁵² represents a hydrogen atom, a hydroxyl group, a halogen atom, linear or A branched alkyl group, a linear or branched halogenated alkyl group, or a linear or branched alkoxy group; R ⁵³ is an aryl group which may have a substituent; u "Is an integer from 1 to 3.]

In the general formula (b-0), R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic fluorinated alkyl group.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms. Also. The fluorination rate of the fluorinated alkyl group (ratio of the number of substituted fluorine atoms to the total number of hydrogen atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%, particularly hydrogen atoms. Are preferably substituted with a fluorine atom because the strength of the acid is increased.
R ⁵¹ is most preferably a linear alkyl group or a fluorinated alkyl group.

R ⁵² is a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group, a linear or branched alkyl halide group, or a linear or branched alkoxy group.
In R ⁵² , examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom, and a fluorine atom is preferable.
In R ⁵² , the alkyl group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
In R ⁵² , the halogenated alkyl group is a group in which part or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms. Examples of the alkyl group herein are the same as the “alkyl group” in R ⁵² . Examples of the halogen atom to be substituted include the same as those described above for the “halogen atom”. In the halogenated alkyl group, it is desirable that 50 to 100% of the total number of hydrogen atoms are substituted with halogen atoms, and it is more preferable that all are substituted.
In R ⁵² , the alkoxy group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
Among these, R ⁵² is preferably a hydrogen atom.

R ⁵³ is an aryl group which may have a substituent, and examples of the structure of the basic ring (matrix ring) excluding the substituent include a naphthyl group, a phenyl group, and an anthracenyl group. When an ArF excimer laser is used for exposure, a phenyl group is desirable from the viewpoint of absorption of exposure light.
Examples of the substituent include a hydroxyl group and a lower alkyl group (straight or branched chain, preferably having 5 or less carbon atoms, particularly preferably a methyl group).
As the aryl group for R ^53, an aryl group having no substituent is more preferable.
u ″ is an integer of 1 to 3, preferably 2 or 3, and particularly preferably 3.

  Preferable examples of the acid generator represented by the general formula (b-0) include the following.

  The acid generator represented by general formula (b-0) can be used alone or in combination of two or more.

  As other onium salt-based acid generators represented by the general formula (b-0), for example, compounds represented by the following general formula (b-1) or (b-2) are also preferably used. It is done.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、アリール基またはアルキル基を表し；Ｒ^４”は、直鎖、分岐または環状のアルキル基またはフッ素化アルキル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

[Wherein R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group; R ⁴ ″ represents a linear, branched or cyclic alkyl group or fluorinated group. Represents an alkyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. At least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all R ¹ ″ to R ³ ″ are aryl groups.
The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups It may or may not be substituted with a group, a halogen atom or the like. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Is most preferred.
The alkoxy group that may be substituted for the hydrogen atom of the aryl group is preferably an alkoxy group having 1 to 5 carbon atoms, and most preferably a methoxy group or an ethoxy group.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, a straight, include alkyl groups such as branched or cyclic. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
Among these, R ¹ ″ to R ³ ″ are most preferably a phenyl group or a naphthyl group, respectively.

R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group.
The linear alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group is a cyclic group as indicated by R ¹ ″ and preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and more preferably 6 carbon atoms. Most preferably, it is -10.
The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms. Also. The fluorination rate of the fluorinated alkyl group (ratio of fluorine atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%, and particularly those in which all hydrogen atoms are substituted with fluorine atoms. Since the strength of the acid is increased, it is preferable.
R ⁴ ″ is most preferably a linear or cyclic alkyl group or a fluorinated alkyl group.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. Of R ⁵ ″ to R ⁶ ″, two or more are preferably aryl groups, and all of R ⁵ ″ to R ⁶ ″ are most preferably aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
"As ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

  Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate, triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate , Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate. In addition, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

  In addition, in the general formula (b-1) or (b-2), an onium salt-based acid generator in which the anion moiety is replaced with an anion moiety represented by the following general formula (b-3) or (b-4). Can also be used (the cation moiety is the same as (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms and substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Preferably it is C3.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably It is C1-C7, More preferably, it is C1-C3.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid increases, and high-energy light or electron beam of 200 nm or less The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

  In this specification, the oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. is there. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

(In formula (B-1), R ³¹ and R ³² each independently represents an organic group.)

The organic groups of R ³¹ and R ³² are groups containing carbon atoms, and atoms other than carbon atoms (for example, hydrogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.), etc.) You may have.
As the organic group for R ³¹ , a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ³¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.

As the organic group for R ³² , a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３７は２または３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐ”は２または３である。］

[In Formula (B-3), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. p ″ is 2 or 3.]

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more, and still more preferably 90% or more.

As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthracyl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.

The alkyl group or halogenated alkyl group having no substituent of R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group, and most preferably a partially fluorinated alkyl group.
The fluorinated alkyl group in R ³⁵ preferably has 50% or more of the hydrogen atom of the alkyl group fluorinated, more preferably 70% or more, and even more preferably 90% or more. This is preferable because the strength of the acid is increased. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁶ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^33. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent of R ³⁸ include the same alkyl groups or halogenated alkyl groups as those having no substituent of R ³⁵ .
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Also, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO 2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

  Of the above exemplified compounds, the following four compounds are preferred.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazo) disclosed in JP-A-11-322707. Methylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3 -Bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. Door can be.

  (B1) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.

<(D) component>
In the positive resist composition of the present embodiment, a nitrogen-containing organic compound (D) (hereinafter referred to as “component (D)”) is further added as an optional component in order to improve the resist pattern shape, the stability over time. Can be blended.
Since a wide variety of components (D) have already been proposed, any known one may be used. Among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are used. preferable.
Examples of the aliphatic amine include an amine (alkyl amine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms.

Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, and the like; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, and tri-n-octylamine is most preferable.
Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.
These may be used alone or in combination of two or more.
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

<Optional component>
In the positive resist composition of the present embodiment, an organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof (optional derivative) is used as an optional component for the purpose of preventing sensitivity deterioration and improving the resist pattern shape, retention stability, and the like. E) (hereinafter referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable. Salicylic acid is particularly preferable.
Phosphorus oxoacids or derivatives thereof include phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester and other phosphoric acid or derivatives thereof such as phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid- Like phosphonic acids such as di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, phosphonic acid dibenzyl ester and derivatives thereof, phosphinic acids such as phosphinic acid, phenylphosphinic acid and their esters Derivatives.
(E) A component is used in the ratio of 0.01-5.0 mass parts per 100 mass parts of (A) component.

  In the positive resist composition of the present embodiment, there are further miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coating properties, and dissolution inhibitors. , Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be added as appropriate.

The positive resist composition of the present embodiment can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone;
Ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-amyl ketone, methyl isoamyl ketone, 2-heptanone;
Polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and derivatives thereof;
Compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate or dipropylene glycol monoacetate, monomethyl ether, monoethyl ether, monopropyl of the polyhydric alcohols or the compound having an ester bond Derivatives of polyhydric alcohols such as ethers, monoalkyl ethers such as monobutyl ether or compounds having an ether bond such as monophenyl ether;
Cyclic ethers such as dioxane and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, etc. Can be mentioned.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.

Among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable. PGMEA is particularly preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
The amount of the component (S) used is not particularly limited, but is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is 2 -20% by mass, preferably 5-15% by mass.

≪Resist pattern formation method≫
A method of forming a resist pattern using the positive resist composition of the present embodiment can be performed as follows, for example.
That is, first, the positive resist composition is applied onto a substrate such as a silicon wafer with a spinner, and prebaking (PAB) is performed at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to 90 seconds. After this, ArF excimer laser light is selectively exposed through a desired mask pattern using, for example, an ArF exposure apparatus, and then subjected to PEB (post-exposure heating) for 40 to 120 seconds under a temperature condition of 80 to 150 ° C. , Preferably 60-90 seconds. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide. In this way, a resist pattern faithful to the mask pattern can be obtained.
An organic or inorganic antireflection film can be provided between the substrate and the coating layer of the resist composition.
The wavelength used for exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray Or the like. In particular, EB can be preferably used.

According to the positive resist composition of this embodiment, excellent resolution can be obtained and a fine resist pattern can be formed. In addition, a highly perpendicular shape can be obtained in the cross-sectional shape of the resist pattern.
As shown in the results of Examples described later, the use of the specific compound (B0) as the component (B) contributes to the improvement of the resolution and the improvement of the perpendicularity in the cross-sectional shape. . The reason is not clear, but since the hydrophobicity of the compound (B0) is relatively low, the affinity with the alkaline developer in the exposed area is improved during development, and the exposed area is more easily dissolved by the developer. It is presumed to progress to.
In addition, since the compound (B0) has good solubility in the organic solvent (S), the content of the compound (B0) is maintained without deteriorating the stability over time in the resist composition and suppressing the occurrence of defects. Can be increased to improve sensitivity.

[Second Embodiment]
The second embodiment of the resist composition of the present invention comprises (A _P ) an acid dissociable, dissolution inhibiting group, a resin component whose alkali solubility is increased by the action of an acid, and (B) an acid generated by exposure. A positive resist composition containing an acid generator component, wherein the (A _P ) component has a structural unit (a11) derived from hydroxystyrene, an acid dissociable, dissolution inhibiting group, and is in the α-position And a resin component (A _P 2) containing a structural unit (a12) derived from an acrylate ester to which a fluorine atom or a fluorinated lower alkyl group is bonded, and the component (B) is represented by the general formula (B-0) Is a positive resist composition containing a compound (B0) represented by

<Resin component ( _AP2 )>
Structural unit (a11)
The structural unit (a11) in the resin component (A _P 2) can be the same as the structural unit (a1) derived from hydroxystyrene in the resin component (A _P 1) of the first embodiment. .
In the present embodiment, a combination of the structural unit (a11) and a structural unit (a12) described later can be used to form a high-resolution pattern with reduced LER. Moreover, dry etching tolerance improves by having a structural unit (a11). Furthermore, there is an advantage that hydroxystyrene as a raw material is easily available and is inexpensive.

In this embodiment, the structural unit (a11) can be used alone or in combination of two or more.
In the general formula (a-1) representing the structural unit (a1) of the first embodiment as the structural unit (a11), R is a hydrogen atom, o is 1, and the hydroxyl group is in the para position. Particularly preferred are those wherein p is 0.
In the (A _P 2) component, the proportion of the structural unit (a11) is preferably 10 to 85 mol%, more preferably 15 to 70 mol%, based on all the structural units constituting the (A _p 2) component. Preferably, 20 to 60 mol% is more preferable, and 25 to 55 mol% is particularly preferable. Within this range, moderate alkali solubility is obtained, and the balance with other structural units is good.

Structural unit (a12)
The structural unit (a12) is a structural unit derived from an acrylate ester having an acid dissociable, dissolution inhibiting group and having a fluorine atom or a fluorinated lower alkyl group bonded to the α-position.
In the structural unit (a12), as the fluorine atom or the fluorinated lower alkyl group bonded to the α-position of the acrylate ester, a fluorine atom as R in the general formula (a-1) in the first embodiment Or the thing similar to a fluorinated lower alkyl group is mentioned.
In the structural unit (a12), a fluorinated lower alkyl group is preferably bonded to the α-position of the acrylate ester.
Examples of the structural unit (a12) include those represented by the following general formula (a12-1).

［式中、Ｒ^１０はフッ素原子またはフッ素化低級アルキル基を表し、Ｒ^１１は酸解離性溶解抑制基又は酸解離性溶解抑制基を有する有機基を表す。］

[Wherein, R ¹⁰ represents a fluorine atom or a fluorinated lower alkyl group, and R ¹¹ represents an organic group having an acid dissociable, dissolution inhibiting group or an acid dissociable, dissolution inhibiting group. ]

In the general formula (a12-1), examples of R ¹⁰ include the same fluorine atom or fluorinated lower alkyl group as R in the general formula (a-1) in the first embodiment. A trifluoromethyl group is preferred.

The acid dissociable, dissolution inhibiting group as R ¹¹ is not particularly limited. For example, a resin for resist compositions such as for KrF excimer laser and ArF excimer laser is appropriately selected from those proposed. be able to.
When R ¹¹ is an organic group having an acid dissociable, dissolution inhibiting group, the portion other than the acid dissociable, dissolution inhibiting group in R ¹¹ is a group containing a carbon atom, and an atom other than a carbon atom (for example, hydrogen atom, oxygen Atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.) and the like.

The “organic group having an acid dissociable, dissolution inhibiting group” as R ¹¹ is, for example, [—Y′-Z ′] (Y ′ is an organic group, and Z ′ is an acid dissociable, dissolution inhibiting group). It is a group represented.
Z ′ is the same as the acid dissociable, dissolution inhibiting group as R ¹¹ in the general formula (a12-1). Y ′ is preferably an organic group containing an aliphatic cyclic group. The aliphatic cyclic group for Y ′ is the same as the aliphatic cyclic group for Y10 described later.
Y ′ is preferably derived from an aliphatic cyclic group having —OH or —COOH as a substituent, and a hydrogen atom of the —OH or —COOH is substituted with the acid dissociable, dissolution inhibiting group Z ′. This constitutes [−Y′−Z ′].

  The following chemical formulas (I), (III) and (IV) are specific examples of acid dissociable, dissolution inhibiting groups, and the following chemical formula (II) is a specific example of “an organic group having an acid dissociable, dissolution inhibiting group”.

Acid dissociable, dissolution inhibiting group (I)
The acid dissociable, dissolution inhibiting group (I) is a group represented by the following general formula (I). By including the acid dissociable, dissolution inhibiting group (I), the effect of this embodiment is further improved.

［式中、Ｘ^１０は脂肪族環式基、芳香族環式炭化水素基または低級アルキル基を表し、Ｒ^１２は水素原子または低級アルキル基を表し、もしくはＸ^１０およびＲ^１２がそれぞれ独立に炭素数１〜５のアルキレン基であってＸ^１０の末端とＲ^１２の末端とが結合していてもよく、Ｒ^１３は低級アルキル基または水素原子を表す。］

[Wherein, X ¹⁰ represents an aliphatic cyclic group, an aromatic cyclic hydrocarbon group or a lower alkyl group, R ¹² represents a hydrogen atom or a lower alkyl group, or X ¹⁰ and R ¹² each independently represent carbon. It may be an alkylene group having 1 to 5 and the terminal end and R ¹² in X ¹⁰ bonded, R ¹³ is a lower alkyl group or a hydrogen atom. ]

In formula (I), X ¹⁰ represents an aliphatic cyclic group, an aromatic cyclic hydrocarbon group or a lower alkyl group.
The aliphatic cyclic group for X ¹⁰ is a monovalent aliphatic cyclic group. The aliphatic cyclic group can be appropriately selected from, for example, those proposed in a number of conventional ArF resists. Specific examples of the aliphatic cyclic group include an aliphatic monocyclic group having 5 to 7 carbon atoms and an aliphatic polycyclic group having 10 to 16 carbon atoms. Examples of the aliphatic monocyclic group having 5 to 7 carbon atoms include groups in which one hydrogen atom has been removed from a monocycloalkane. Specifically, one hydrogen atom has been removed from cyclopentane, cyclohexane and the like. Group. Examples of the aliphatic polycyclic group having 10 to 16 carbon atoms include groups in which one hydrogen atom has been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specifically, adamantane, norbornane, Examples include groups in which one hydrogen atom has been removed from a polycycloalkane such as isobornane, tricyclodecane, and tetracyclododecane. Among these, an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are industrially preferable, and an adamantyl group is particularly preferable.
Examples of the aromatic cyclic hydrocarbon group for X ¹⁰ include aromatic polycyclic groups having 10 to 16 carbon atoms. Specific examples include groups in which one hydrogen atom has been removed from naphthalene, anthracene, phenanthrene, pyrene, and the like. Specific examples include 1-naphthyl group, 2-naphthyl group, 1-anthracenyl group, 2-anthracenyl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 1-pyrenyl group, and the like. A naphthyl group is particularly preferred industrially.
Examples of the lower alkyl group for X ¹⁰ include the same lower alkyl groups as R in the general formula (a-1) in the first embodiment.
X ¹⁰ is preferably a lower alkyl group, more preferably a methyl group or an ethyl group, and most preferably an ethyl group.

In the formula (I), examples of the lower alkyl group for R ¹² include the same lower alkyl groups as R in the general formula (a-1) in the first embodiment. Industrially, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
R ¹³ represents a lower alkyl group or a hydrogen atom. As the lower alkyl group for R ^{13, the same as} the lower alkyl group for R ¹² can be exemplified. R ¹³ is preferably a hydrogen atom industrially.

In Formula (I), X ¹⁰ and R ¹² are each independently an alkylene group having 1 to 5 carbon atoms, and the end of X ^{10 and} the end of R ¹² may be bonded to each other.
In this case, in the formula (I), R ¹² , X ¹⁰ , the oxygen atom to which X ¹⁰ is bonded, and the carbon atom to which the oxygen atom and R ¹² are bonded form a cyclic group. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

As the acid dissociable, dissolution inhibiting group (I), a group in which R ¹³ is a hydrogen atom is particularly preferable from the viewpoint of the effect of this embodiment. Specific examples thereof include, for example, a group in which X ¹⁰ is an alkyl group, that is, a 1-alkoxyalkyl group includes a 1-methoxyethyl group, a 1-ethoxyethyl group, a 1-iso-propoxyethyl group, a 1-n-butoxy group. Examples include an ethyl group, 1-tert-butoxyethyl group, methoxymethyl group, ethoxymethyl group, iso-propoxymethyl group, n-butoxymethyl group, tert-butoxymethyl group and the like. Examples of the group in which X ¹⁰ is an aliphatic cyclic group include 1-cyclohexyloxyethyl group, 1- (2-adamantyl) oxymethyl group, and 1- (1- And adamantyl) oxyethyl group. Examples of the group in which X is an aromatic cyclic hydrocarbon group include a 1- (2-naphthyl) oxyethyl group represented by the following formula (Ib).
Among these, a 1-ethoxyethyl group is particularly preferable.

.Organic groups (II) having acid dissociable, dissolution inhibiting groups
The organic group (II) having an acid dissociable, dissolution inhibiting group (hereinafter sometimes simply referred to as acid dissociable, dissolution inhibiting group (II)) is a group represented by the following general formula (II). By including the acid dissociable, dissolution inhibiting group (II), the effect of this embodiment is further improved. Also, the exposure margin is improved.

［式中、Ｘ^１１は脂肪族環式基、芳香族環式炭化水素基または低級アルキル基を表し、Ｒ^１４は水素原子または低級アルキル基を表し、もしくはＸ^１１およびＲ^１４がそれぞれ独立に炭素数１〜５のアルキレン基であってＸ^１１の末端とＲ^１４の末端とが結合していてもよく、Ｒ^１５は低級アルキル基または水素原子を表し、Ｙ^１０は脂肪族環式基を含む有機基を表す。

[Wherein, X ¹¹ represents an aliphatic cyclic group, an aromatic cyclic hydrocarbon group or a lower alkyl group, R ¹⁴ represents a hydrogen atom or a lower alkyl group, or X ¹¹ and R ¹⁴ each independently represent carbon. An alkylene group of 1 to 5, the end of X ^{11 and} the end of R ¹⁴ may be bonded, R ¹⁵ represents a lower alkyl group or a hydrogen atom, and Y ¹⁰ contains an aliphatic cyclic group Represents an organic group.

In the formula (II), X ¹¹ , R ¹⁴ and R ¹⁵ are the same as X ¹⁰ , R ¹² and R ¹³ in the formula (I), respectively.
Examples of the organic group containing an aliphatic cyclic group represented by Y ¹⁰ include an aliphatic cyclic group or a divalent group derived from an aliphatic cyclic group having a substituent. The aliphatic cyclic group for Y ¹⁰ is preferably a group obtained by further removing one or more hydrogen atoms from the aliphatic cyclic group for X ¹⁰ .
Y ¹⁰ is a group in which one hydrogen atom of the aliphatic cyclic group in X ¹⁰ is substituted with —OH or —COOH, and the hydrogen atom of —OH or —COOH is removed, The hydrogen atom of —OH or —COOH is more preferably substituted with the acid dissociable, dissolution inhibiting group [—CR ¹⁴ R ¹⁵ —O—X ¹¹ ]. Y ¹⁰ is most preferably a divalent group in which a hydrogen atom of —OH of the 3-hydroxy-1-adamantyl group is removed. The acid dissociable, dissolution inhibiting group [—CR ¹⁴ R ¹⁵ —O—X ¹¹ ] is most preferably a 1-ethoxyethyl group.

Acid dissociable, dissolution inhibiting group (III)
The acid dissociable, dissolution inhibiting group (III) is a chain or cyclic tertiary alkyl group. By including the acid dissociable, dissolution inhibiting group (III), the effect of this embodiment is improved. Also, the exposure margin is improved.
4-10 are preferable and, as for carbon number of a chain | strand-shaped tertiary alkyl group, 4-8 are more preferable. More specific examples of the chain-like tertiary alkyl group include a tert-butyl group and a tert-amyl group.
The cyclic tertiary alkyl group is a monocyclic or polycyclic monovalent saturated hydrocarbon group containing a tertiary carbon atom on the ring. 4-12 are preferable and, as for carbon number of a cyclic | annular tertiary alkyl group, 5-10 are more preferable. More specifically, as the cyclic tertiary alkyl group, 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 2-methyl-2-adamantyl group, 2-ethyl -2-adamantyl group and the like.
As the acid dissociable, dissolution inhibiting group (III), a chain-like tertiary alkyl group is preferable, and a tert-butyl group is particularly preferable from the viewpoint of the effect of the present embodiment and an excellent exposure margin.

Acid dissociable, dissolution inhibiting group (IV)
The acid dissociable, dissolution inhibiting group (IV) is an acid dissociable, dissolution inhibiting group not classified into the acid dissociable, dissolution inhibiting groups (I) to (III). As the acid dissociable, dissolution inhibiting group (IV), among the conventionally known acid dissociable, dissolution inhibiting groups, any acid dissociable, dissolution inhibiting group not classified into the above acid dissociable, dissolution inhibiting groups (I) to (III) can be used. Specific examples thereof include a chain-like tertiary alkoxycarbonyl group and a chain-like tertiary alkoxycarbonylalkyl group.
4-10 are preferable and, as for carbon number of a chain | strand-shaped tertiary alkoxycarbonyl group, 4-8 are more preferable. Specific examples of the chain-like tertiary alkoxycarbonyl group include a tert-butoxycarbonyl group and a tert-amyloxycarbonyl group.
The chain tertiary alkoxycarbonylalkyl group preferably has 4 to 10 carbon atoms, and more preferably 4 to 8 carbon atoms. Specific examples of the chain-like tertiary alkoxycarbonylalkyl group include a tert-butoxycarbonylmethyl group, a tert-amyloxycarbonylmethyl group, and the like.

  In this embodiment, the acid dissociable, dissolution inhibiting group in the structural unit (a12) includes at least one selected from the group consisting of acid dissociable, dissolution inhibiting groups (I), (II), and (III). It is preferable because it has an excellent effect, and it preferably includes an acid dissociable, dissolution inhibiting group (II).

The structural unit (a12) can be used alone or in combination of two or more.
In the component (A _p 2), the proportion of the structural unit (a12) is preferably 1 to 80 mol%, and preferably 1 to 60 mol% with respect to all the structural units constituting the polymer compound (A _p 2). Is more preferable, 1 to 50 mol% is more preferable, 1 to 40 mol% is particularly preferable, and 2 to 35 mol% is most preferable. By setting it to the lower limit value or more, a pattern can be obtained when the resist composition is used, and by setting it to the upper limit value or less, the balance with other structural units is good.

Structural unit (a13)
The component (A _p 2) preferably further has a structural unit (a13) in which the hydrogen atom of the hydroxyl group in the structural unit (a11) is substituted with an acid dissociable, dissolution inhibiting group. Thereby, high etching resistance and resolution can be achieved.
Examples of the acid dissociable, dissolution inhibiting group for the structural unit (a13) include the same groups as those described above for the structural unit (a12). Among these, it is preferable to include at least one selected from the group consisting of acid dissociable, dissolution inhibiting groups (I), (II), and (III) because the effect of this embodiment is excellent. Preferably it contains the group (I). Most preferred is a 1-ethoxyethyl group.

The structural unit (a13) can be used alone or in combination of two or more.
In the polymer compound (A _p 2), the proportion of the structural unit (a13) is preferably 5 to 50 mol% with respect to all the structural units constituting the polymer compound (A _p 2), and 5 to 45 More preferably, mol% is more preferable, 10-40 mol% is further more preferable, and 15-40 mol% is especially preferable. By making the structural unit (a13) greater than the lower limit, the effect of the present embodiment is high, and by making the upper limit or less, the balance with other structural units is good.

Structural unit (a14)
The (A _p 2) component preferably further has a structural unit (a14) derived from an acrylate ester having an alcoholic hydroxyl group and having a fluorine atom or a fluorinated lower alkyl group bonded to the α-position. By having such a structural unit (a14), the effect of the present embodiment is further improved.
In the structural unit (a14), the fluorine atom or fluorinated lower alkyl group bonded to the α-position of the acrylate ester is the same as in the structural unit (a12).

  Preferred examples of the structural unit (a14) include structural units having a chain or cyclic alkyl group having an alcoholic hydroxyl group. That is, the structural unit (a14) is a structural unit derived from an acrylate ester having a linear or cyclic alkyl group containing an alcoholic hydroxyl group and having a fluorine atom or a fluorinated lower alkyl group bonded to the α-position. Preferably there is.

The structural unit (a14) is a structural unit derived from an acrylate ester having an alcoholic hydroxyl group-containing cyclic alkyl group and having a fluorine atom or a fluorinated lower alkyl group bonded to the α-position (hereinafter simply referred to as “hydroxyl group”). When it has a “structural unit having a cyclic alkyl group”, the resolution is improved and the etching resistance is also improved.
The structural unit (a14) is a structural unit derived from an acrylate ester having an alcoholic hydroxyl group-containing chain alkyl group and having a fluorine atom or a fluorinated lower alkyl group bonded to the α-position (hereinafter referred to as “the structural unit”). Simply having “a structural unit having a hydroxyl group-containing chain alkyl group”), the hydrophilicity of the entire component (A _p ) is further increased, the affinity with the developer is increased, and the resolution is further improved. improves.

"Structural unit having a hydroxyl group-containing cyclic alkyl group"
Examples of the structural unit having a hydroxyl group-containing cyclic alkyl group include a structural unit in which a hydroxyl group-containing cyclic alkyl group is bonded to an ester group [—C (O) O—] of an acrylate ester. Here, the “hydroxyl group-containing cyclic alkyl group” is a group in which a hydroxyl group is bonded to a cyclic alkyl group.
It is preferable that 1-3 hydroxyl groups are couple | bonded, for example, More preferably, it is one.
The cyclic alkyl group may be monocyclic or polycyclic, but is preferably a polycyclic group. Moreover, it is preferable that carbon number of a cyclic alkyl group is 5-15.
Specific examples of the cyclic alkyl group include the following.
Examples of the monocyclic cyclic alkyl group include groups in which 1 to 4 hydrogen atoms have been removed from cycloalkane. More specifically, examples of the monocyclic cyclic alkyl group include groups in which 1 to 4 hydrogen atoms have been removed from cyclopentane and cyclohexane, and among these, a cyclohexyl group is preferable.
Examples of the polycyclic cyclic alkyl group include groups in which 1 to 4 hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. More specifically, a group obtained by removing 1 to 4 hydrogen atoms from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like can be given.
Such a cyclic alkyl group may be appropriately selected and used from among many that have been proposed as constituting an acid dissociable, dissolution inhibiting group, for example, in a resin for a photoresist composition for an ArF excimer laser process. it can. Among these, a cyclohexyl group, an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are preferred because they are easily available in the industry.
Among these exemplified monocyclic groups and polycyclic groups, a cyclohexyl group and an adamantyl group are preferable, and an adamantyl group is particularly preferable.
As a specific example of the structural unit having a hydroxyl group-containing cyclic alkyl group, for example, a structural unit (a14-1) represented by the following general formula (a14-1) is preferable.

［式中、Ｒ^１６はフッ素原子またはフッ素化低級アルキル基であり、ｓ’は１〜３の整数である。］

[Wherein R ¹⁶ represents a fluorine atom or a fluorinated lower alkyl group, and s ′ represents an integer of 1 to 3. ]

In formula (a14-1), the fluorine atom or fluorinated lower alkyl group for R ^{16 is the same as} the fluorine atom or fluorinated lower alkyl group for R ¹⁰ in formula (a12-1).
s ′ is an integer of 1 to 3, and 1 is most preferable.
The bonding position of the hydroxyl group is not particularly limited, but is preferably bonded to the 3rd position of the adamantyl group.

"Structural unit having a hydroxyl group-containing chain alkyl group"
Examples of the structural unit having a hydroxyl group-containing chain alkyl group include a structural unit in which a chain hydroxyalkyl group is bonded to an ester group [—C (O) O—] of an acrylate ester. Here, the “chain hydroxyalkyl group” means a group in which part or all of hydrogen atoms in a chain (straight chain or branched chain) alkyl group are substituted with a hydroxyl group.
As the structural unit having a hydroxyl group-containing chain alkyl group, a structural unit (a14-2) represented by general formula (a14-2) shown below is particularly desirable.

［式中、Ｒ^１７はフッ素原子またはフッ素化低級アルキル基であり、Ｒ^１８は鎖状のヒドロキシアルキル基である。］

[Wherein, R ¹⁷ represents a fluorine atom or a fluorinated lower alkyl group, and R ¹⁸ represents a chain-like hydroxyalkyl group. ]

R ¹⁷ in formula (a14-2) is the same as R ^{16 in} formula (a14-1).
The hydroxyalkyl group for R ¹⁸ is preferably a lower hydroxyalkyl group having 10 or less carbon atoms, more preferably a lower hydroxyalkyl group having 2 to 8 carbon atoms, and still more preferably a linear chain having 2 to 4 carbon atoms. Lower hydroxyalkyl group.
The number of hydroxyl groups and the bonding position in the hydroxyalkyl group are not particularly limited, but are usually one and preferably bonded to the terminal of the alkyl group.

  In the present embodiment, it is particularly preferable that the structural unit (a14) includes a structural unit having at least a hydroxyl group-containing cyclic alkyl group.

The structural unit (a14) can be used alone or in combination of two or more.
In the component (A _p 2), the proportion of the structural unit (a14) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on the total of all the structural units of the component (A _p 2). 5-30 mol% is further more preferable, and 5-15 mol% is especially preferable. The effect by containing a structural unit (a14) is high by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

Structural unit (a15)
The (A _p 2) component may further have a structural unit (a15) derived from styrene.
In the present embodiment, the structural unit (a15) is not essential, but if it is contained, the solubility in the developer can be adjusted, and the alkali solubility can be controlled by the content thereof, thereby the LER can be controlled. Further reduction can be achieved. Further, there is an advantage that a good isolated line pattern can be obtained.
As the structural unit (a15) in the present embodiment, those similar to the structural unit (a3) derived from styrene in the component (A _P 1) of the first embodiment can be used.

In this embodiment, as the structural unit (a15), one type may be used alone, or two or more types may be used in combination.
When the (A _p 2) component has the structural unit (a15), the proportion of the structural unit (a15) is preferably 1 to 20 mol% with respect to all the structural units constituting the (A _p 2) component, 15 mol% is more preferable and 5-15 mol% is further more preferable. Within this range, the effect of having the structural unit (a15) is high, and the balance with other structural units is also good.

Structural unit (a16)
The component (A _p 2) may contain other structural units (a16) other than the structural units (a11) to (a15) as long as the effects of the present embodiment are not impaired.
The structural unit (a16) is not particularly limited as long as it is another structural unit that is not classified into the structural units (a11) to (a15) described above. For the ArF excimer laser and for the KrF positive excimer laser (preferably ArF excimer) A number of hitherto known materials can be used for resist resins such as lasers.

In the present embodiment, the component (A _p 2) is preferably a copolymer containing at least the structural units (a11) and (a12).
Such a copolymer may be a copolymer composed of the structural units (a11) and (a12), and the structural units (a11) and (a12) and the structural units (a13), (a14), It may be a copolymer having at least one of (a15). Since the effect of this embodiment is excellent, the binary copolymer (A _p 2-2) composed of the structural units (a11) and (a12); 3 composed of the structural units (a11), (a12) and (a13). Copolymer (A _p 2-3); quaternary copolymer (A _p 2-4-1) composed of structural units (a11), (a12), (a13) and (a14); structural unit (a11) ), (a12), (a13) and (4 terpolymer _(A p 2-4-2) or the like is preferably composed of a15), in particular, terpolymer _(A p 2-3) and quaternary A copolymer (A _p 2-4-1) is preferred, and a quaternary copolymer (A _p 2-4-1) is most preferred.

In the ternary copolymer (A _p 2-3), the proportion of the structural unit (a11) is 10 to 85 mol% with respect to all the structural units constituting the ternary copolymer (A _p 2-3). It is preferably 15 to 70 mol%, more preferably 20 to 60 mol%, still more preferably 25 to 55 mol%. 10-80 mol% is preferable, as for the ratio of a structural unit (a12), 15-70 mol% is more preferable, 20-50 mol% is further more preferable, and 20-40 mol% is especially preferable. The proportion of the structural unit (a13) is preferably 5 to 50 mol%, more preferably 5 to 45 mol%, still more preferably 10 to 40 mol%, and particularly preferably 15 to 40 mol%.

In the quaternary copolymer (A _p 2-4-1), the proportion of the structural unit (a11) is 10 with respect to all the structural units constituting the quaternary copolymer (A _p 2-4-1). It is preferable that it is -85 mol%, 20-80 mol% is more preferable, 30-80 mol% is further more preferable, 40-70 mol% is especially preferable. The proportion of the structural unit (a12) is preferably 1 to 80 mol%, more preferably 1 to 60 mol%, further preferably 1 to 40 mol%, particularly preferably 1 to 30 mol%, and 5 to 20 Mole% is most preferred. The proportion of the structural unit (a13) is preferably 5 to 50 mol%, more preferably 5 to 45 mol%, still more preferably 10 to 40 mol%, and particularly preferably 15 to 40 mol%. The proportion of the structural unit (a14) is preferably 5 to 50 mol%, more preferably 5 to 45 mol%, still more preferably 5 to 30 mol%, and particularly preferably 5 to 15 mol%.

In these copolymers, the acid dissociable, dissolution inhibiting group preferably contains two or more selected from the group consisting of acid dissociable, dissolution inhibiting groups (I), (II) and (III).
In particular, a combination of the acid dissociable, dissolution inhibiting group (I) and the acid dissociable, dissolution inhibiting group (II) or (III) is preferable.

Further, the ternary or quaternary copolymer may be mixed and used. For example, (A _p 2-3) mixed resin having different constituent unit ratios, (A 1-4-1) mixed resins having different constituent unit ratios, (A _p 2-3) and (A _p 2-4-1) and the like.

The component (A _p 2) is obtained by polymerizing a monomer for deriving each structural unit by a conventional method, for example, a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). be able to. As an example, for example, after preparing a monomer in which the hydroxyl group of hydroxystyrene is protected with a protecting group such as an acetyl group and a monomer corresponding to the structural unit (a12), these monomers are copolymerized by a conventional method. This can be produced by substituting the protective group with a hydrogen atom to form the structural unit (a11) by hydrolysis.
In the case of the quaternary copolymer (A _p 2-4-1), for example, a monomer in which the hydroxyl group of hydroxystyrene is protected with a protective group such as an acetyl group, and a monomer corresponding to the structural unit (a14). After preparing and copolymerizing these monomers by a conventional method, the protective group is replaced with a hydrogen atom to form a structural unit (a11), and then a part of the hydroxyl groups of the structural unit (a11) and It can be produced by protecting a part of the hydroxyl group of the structural unit (a14) with an acid dissociable, dissolution inhibiting group by a well-known method to form the structural unit (a13) and the structural unit (a12), respectively.

The weight average molecular weight of the (A _p 2) component (polystyrene conversion by gel permeation chromatography (GPC), the same shall apply hereinafter) is preferably 3000 to 30000, more preferably 5000 to 20000, and even more preferably 5000 to 15000. When the mass average molecular weight is 30000 or less, sufficient solubility in a resist solvent can be secured, and LER can be reduced. Moreover, it is easy to adjust the solubility with respect to a developing solution as it is 3000 or more. In addition, dry etching resistance is improved and film loss is improved.
Further, the smaller the degree of dispersion (Mw / Mn (number average molecular weight)) of the (A _p 2) component (the closer to monodispersion), the better the resolution and the better. The dispersity is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.0 to 2.5.

As the component (A _p 2), one type may be used, or two or more types may be used in combination.
In the present embodiment, as the (A _P ) component, in addition to the (A _p 2) component, generally a chemically amplified positive type such as a PHS resin and an acrylic resin, as long as the effects of the present embodiment are not impaired. A resin used as a resist resin may be contained.
In the component (A _P ), the proportion of the component (A _p 2) is preferably 50% by mass or more, more preferably 80 to 100% by mass, and most preferably 100% by mass for the effect of the present embodiment. %.
In the positive resist composition of this embodiment, the content of the (A _P ) component may be adjusted according to the resist film thickness to be formed.

The component (B) in the present embodiment is the same as in the first embodiment.
In the positive resist composition of this embodiment, the component (D) can be blended as in the first embodiment.
Further, as in the first embodiment, an optional component such as component (E) can be contained. The positive resist composition of this embodiment can be produced by dissolving the material in an organic solvent (S). it can. The component (S) is the same as that in the first embodiment.

A method of forming a resist pattern using the positive resist composition of the present embodiment can be performed by the same method as in the first embodiment.
In particular, since the positive resist composition of the present embodiment has high stability under vacuum, it can be suitably used for forming a resist pattern including an exposure process under vacuum, such as KrF excimer laser, electron beam or It is preferable for EUV (extreme ultraviolet), and particularly suitable for an electron beam.

According to this embodiment, the same effect as that of the first embodiment, which is presumed to be the contribution of the compound (B0), can be obtained.
Further, according to the present embodiment, by using the specific (A _P 2) component as the (A) component, a high-resolution pattern with reduced LER can be formed. The reason why such an effect can be obtained is as follows. That is, in the structural unit (a12), the acid dissociable, dissolution inhibiting group is easily dissociated by bonding a fluorine atom or a fluorinated lower alkyl group to the α-position. Since the acid dissociable, dissolution inhibiting group is easily dissociated, the ratio of acid dissociable, dissolution inhibiting group present in the exposed area during the exposure is high (deprotection rate), and the alkali solubility in the exposed area is greatly increased. The difference in alkali solubility (dissolution contrast) between the unexposed area and the exposed area is increased. In addition, since the structural unit (a12) is a structural unit derived from an acrylate ester, the KrF excimer laser is more than the case where only the hydroxystyrene-based structural unit such as the structural unit (a11) or the structural unit (a13) is included. Transparency to an exposure light source such as the above increases, exposure light is sufficiently transmitted from the top of the resist film to the vicinity of the substrate interface, and the generation of acid from the component (B) is efficiently decomposed. As a result, it is estimated that LER is reduced and resolution is improved.
Furthermore, in the present embodiment, because the specific ( _AP 2) component is used, the reason is not clear, but the exposure margin is high and the exposure amount is slightly shifted. Little change in resist pattern dimensions. The formed resist pattern is also excellent in shape such as reduced LER and high cross-sectional rectangularity.

[Third Embodiment]
A third embodiment of the resist composition of the present invention is a negative resist containing (A _N ) an alkali-soluble resin, (B) an acid generator component that generates an acid upon exposure, and (C) a crosslinking agent component. The composition (A _N ) contains a copolymer (A _N 1) containing a structural unit (a21) derived from hydroxystyrene and a structural unit (a22) derived from styrene. The negative resist composition in which the component (B) contains the compound (B0) represented by the general formula (B-0).
The negative resist composition of the present embodiment is suitable for KrF excimer laser and EB (electron beam).

<Resin component (A _N 1)>
Structural unit (a21)
The structural unit (a21) is a structural unit derived from hydroxystyrene, and the same structural unit (a1) derived from hydroxystyrene in the resin component (A _P 1) of the first embodiment is used. be able to.

As the structural unit (a21), one type or a mixture of two or more types can be used.
In the component (A _N 1), the proportion of the structural unit (a21) is preferably 10 to 85 mol%, and preferably 30 to 85 mol% with respect to all the structural units constituting the component (A _N 1). More preferably, it is more preferably 40 to 85 mol%, and most preferably 60 to 85 mol%. Within this range, moderate alkali solubility is obtained when the resist composition is prepared, and the balance with other structural units is good.

Structural unit (a22)
The structural unit (a22) is a structural unit derived from styrene.
As the structural unit (a22) in the present embodiment, the same structural unit (a3) derived from styrene in the component (A _P 1) of the first embodiment can be used.

As the structural unit (a22), one type or a mixture of two or more types can be used.
In the component (A _N 1), the proportion of the structural unit (a22) is preferably 5 to 40 mol%, more preferably 10 to 40 mol%, based on all the structural units constituting the component (A _N 1). It is especially preferable that it is -35 mol%, and it is most preferable that it is 15-30 mol%. Within this range, moderate alkali solubility can be obtained when a resist composition is obtained, and the balance with other structural units is also good.

The component (A _N 1) may have another copolymerizable structural unit as a structural unit other than the structural units (a21) and (a22).
Such a structural unit is not particularly limited as long as it is another structural unit that is not classified into the structural units (a21) and (a22) described above. For resists such as for EB, for KrF excimer laser, for ArF excimer laser, etc. A large number of conventionally used resins can be used.

The component (A _N 1) is preferably a copolymer having the structural units (a21) and (a22) as main components.
Here, the “main component” means that the sum of the structural units (a21) and (a22) is 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more. is there. Most preferably, it is 100 mol%. That is, the (A _N 1) component is preferably a copolymer composed of the structural units (a21) and (a22).

As the (A _N 1) component, a copolymer composed of a combination of structural units represented by the following chemical formula (A1-1) is particularly preferable.

［式中、Ｒは前記と同じである。］

[Wherein, R is the same as defined above. ]

The mass average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of the component (A _N 1) is not particularly limited, but is preferably 1000 to 10,000, more preferably 1000 to 7000, and more preferably 1500 to 3000. Is most preferred.
When it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and the dry etching resistance and resist pattern cross-sectional shape that are larger than the lower limit of this range are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.

The component (A _N 1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). it can.
In addition, for the ( _AN 1) component, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination in the above polymerization. it may be introduced -C _{(CF 3)} 2 -OH group at the terminal. As described above, a copolymer introduced with a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing

When the (A _N 1) component is used as the (A _N ) component, one or more of the above (A _N 1) components can be mixed and used.
Further, the (A _N ) component may contain a resin component other than the (A _N 1) component.
However, when using the _(A N 1) component, the proportion of _{(A N)} in the component _(A N 1) component is more preferably preferably at least 50 mass%, 70 mass% or more, It is particularly preferably 80% by mass or more, and most preferably 100% by mass.
In the negative resist composition of this embodiment, the content of the (A _N ) component may be adjusted according to the resist film thickness to be formed.

<Crosslinking agent component (C)>
In this embodiment, the component (C) can be arbitrarily selected from cross-linking agents used in chemical amplification type negative resist compositions known so far.
Specifically, for example, 2,3-dihydroxy-5-hydroxymethylnorbornane, 2-hydroxy-5,6-bis (hydroxymethyl) norbornane, cyclohexanedimethanol, 3,4,8 (or 9) -trihydroxytri Aliphatic cyclic carbonization having a hydroxyl group or a hydroxyalkyl group or both such as cyclodecane, 2-methyl-2-adamantanol, 1,4-dioxane-2,3-diol, 1,3,5-trihydroxycyclohexane Examples thereof include hydrogen or an oxygen-containing derivative thereof.

In addition, amino group-containing compounds such as melamine, acetoguanamine, benzoguanamine, urea, ethylene urea, propylene urea, glycoluril are reacted with formaldehyde or formaldehyde and lower alcohol, and the hydrogen atom of the amino group is hydroxymethyl group or lower alkoxymethyl. And a compound substituted with a group.
Of these, those using melamine are melamine-based crosslinking agents, those using urea are urea-based crosslinking agents, those using alkylene ureas such as ethylene urea and propylene urea are alkylene urea-based crosslinking agents, and glycoluril is used. This was called a glycoluril-based crosslinking agent.
The component (C) is preferably at least one selected from the group consisting of melamine-based crosslinking agents, urea-based crosslinking agents, alkylene urea-based crosslinking agents, and glycoluril-based crosslinking agents, and glycoluril-based crosslinking agents are particularly preferred. preferable.

  Melamine-based crosslinking agents include compounds in which melamine and formaldehyde are reacted to replace the amino group hydrogen atom with a hydroxymethyl group, and melamine, formaldehyde and lower alcohol are reacted to convert the amino group hydrogen atom into a lower alkoxy group. Examples include compounds substituted with a methyl group. Specific examples include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxybutyl melamine, and the like, among which hexamethoxymethyl melamine is preferable.

  Urea-based crosslinking agents include compounds in which urea and formaldehyde are reacted to replace amino group hydrogen atoms with hydroxymethyl groups, and urea, formaldehyde and lower alcohols are reacted to convert amino group hydrogen atoms into lower alkoxy groups. Examples include compounds substituted with a methyl group. Specific examples include bismethoxymethylurea, bisethoxymethylurea, bispropoxymethylurea, bisbutoxymethylurea and the like, with bismethoxymethylurea being preferred.

  As an alkylene urea type crosslinking agent, the compound represented by the following general formula (C-1) is mentioned.

（式中のＲ^１’とＲ^２’はそれぞれ独立に水酸基又は低級アルコキシ基であり、Ｒ^３’とＲ^４’はそれぞれ独立に水素原子、水酸基又は低級アルコキシ基であり、ｖは０〜２の整数である。）

(In the formula, R ¹ ′ and R ² ′ are each independently a hydroxyl group or a lower alkoxy group, R ³ ′ and R ⁴ ′ are each independently a hydrogen atom, a hydroxyl group or a lower alkoxy group, and v is 0-2. Is an integer.)

When R ¹ ′ and R ² ′ are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ¹ ′ and R ² ′ may be the same or different from each other. More preferably, they are the same.
When R ³ ′ and R ⁴ ′ are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ³ ′ and R ⁴ ′ may be the same or different from each other. More preferably, they are the same.
v is an integer of 0 to 2, preferably 0 or 1.
As the alkylene urea crosslinking agent, a compound in which v is 0 (ethylene urea crosslinking agent) and / or a compound in which v is 1 (propylene urea crosslinking agent) are particularly preferable.

  The compound represented by the general formula (C-1) can be obtained by a condensation reaction of alkylene urea and formalin and by reacting this product with a lower alcohol.

  Specific examples of the alkylene urea crosslinking agent include, for example, mono and / or dihydroxymethylated ethylene urea, mono and / or dimethoxymethylated ethylene urea, mono and / or diethoxymethylated ethylene urea, mono and / or dipropoxy Ethylene urea-based crosslinking agents such as methylated ethylene urea, mono and / or dibutoxymethylated ethylene urea; mono and / or dihydroxymethylated propylene urea, mono and / or dimethoxymethylated propylene urea, mono and / or diethoxymethyl Propylene urea-based cross-linking agents such as propylene urea, mono and / or dipropoxymethylated propylene urea, mono and / or dibutoxymethylated propylene urea; 1,3-di (methoxymethyl) 4,5-dihydroxy-2- Imidazolidinone, 1,3-di (Metoki Like, etc.) -4,5-dimethoxy-2-imidazolidinone.

Examples of the glycoluril-based crosslinking agent include glycoluril derivatives in which the N position is substituted with one or both of a hydroxyalkyl group and an alkoxyalkyl group having 1 to 4 carbon atoms. Such glycoluril derivatives can be obtained by condensation reaction of glycoluril and formalin, and by reacting this product with a lower alcohol.
Specific examples of the glycoluril-based crosslinking agent include, for example, mono, di, tri and / or tetrahydroxymethylated glycoluril, mono, di, tri and / or tetramethoxymethylated glycoluril, mono, di, tri and / or Examples include tetraethoxymethylated glycoluril, mono, di, tri and / or tetrapropoxymethylated glycoluril, mono, di, tri and / or tetrabutoxymethylated glycoluril. Of these, tetramethoxymethylated glycoluril is preferable.

(C) A component may be used individually by 1 type and may be used in combination of 2 or more type.
The content of the entire component (C) in the negative resist composition of the present embodiment is preferably 3 to 30 parts by mass, more preferably 3 to 25 parts by mass with respect to 100 parts by mass of the (A _N ) component. Most preferred is 20 parts by weight. When the content of the component (C) is at least the lower limit value, the crosslinking formation proceeds sufficiently and a good resist pattern can be obtained. Moreover, when it is below this upper limit, the storage stability of the resist coating solution is good, and the deterioration of sensitivity with time is suppressed.

The component (B) in the present embodiment is the same as in the first embodiment.
In the negative resist composition of the present embodiment, the component (D) can be blended as in the first embodiment.
Further, as in the first embodiment, an optional component such as the component (E) can be contained. The negative resist composition of the present embodiment can be produced by dissolving the material in an organic solvent (S). it can. Examples of the component (S) are the same as those in the first embodiment. Especially, in this embodiment, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable, and PGME is more preferable.

The method of forming a resist pattern using the negative resist composition of the present embodiment can be performed by the same method as in the first embodiment, and a negative resist pattern is obtained.
In particular, the negative resist composition of this embodiment is suitable for KrF excimer lasers and electron beams.

According to this embodiment, the same effect as that of the first embodiment, which is presumed to be the contribution of the compound (B0), can be obtained.
That is, according to the negative resist composition of this embodiment, excellent resolution can be obtained and a fine resist pattern can be formed. In addition, a highly perpendicular shape can be obtained in the cross-sectional shape of the resist pattern.
The reason is that the hydrophobicity of the compound (B0) is relatively low, so that the affinity with the alkaline developer in the unexposed area during development is improved, and the dissolution of the unexposed area in the developer is better. Presumed to progress.
In addition, since the compound (B0) has good solubility in the organic solvent (S), the content of the compound (B0) is maintained without deteriorating the stability over time in the resist composition and suppressing the occurrence of defects. Can be increased to improve sensitivity.
In addition, the compound (B0) has an advantage of good environmental resistance.

[Fourth Embodiment]
A fourth embodiment of the resist composition of the present invention is a negative resist containing (A _N ) an alkali-soluble resin, (B) an acid generator component that generates an acid upon exposure, and (C) a crosslinking agent component. An acrylic ester containing a constituent unit (a31) containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group and a hydroxyl group-containing aliphatic cyclic group, wherein the component (A _N ) is a composition A negative resist containing a copolymer (A _N 2) containing a structural unit (a32) derived from A, wherein the component (B) contains the compound (B0) represented by the general formula (B-0) It is a composition.
The component (A _N 2) preferably further contains a structural unit (a33) derived from acrylic acid having no cyclic structure and having an alcoholic hydroxyl group in the side chain.
The negative resist composition of the present embodiment is suitable for ArF excimer laser.

<Resin component (A _N 2)>
Structural unit (a31)
The structural unit (a31) contains an aliphatic cyclic group having a fluorinated hydroxyalkyl group. By including the structural unit (a31), swelling of the resist is suppressed and resolution is improved.

The fluorinated hydroxyalkyl group is a group in which part or all of the hydrogen atoms bonded to the carbon atom of the alkyl group in the alkyl group having a hydroxy group (hydroxyl group) are substituted with a fluorine atom. In such a group, the hydrogen atom of the hydroxyl group is easily liberated by fluorination.
In the fluorinated hydroxyalkyl group, the alkyl group is preferably linear or branched. Although carbon number of the said alkyl group is not specifically limited, 1-20 are preferable, 4-16 are more preferable, and it is most preferable that it is 4-12. The number of hydroxyl groups is not particularly limited, but is preferably 1 or 2, and more preferably 1.
Among them, as a fluorinated hydroxyalkyl group, a fluorinated alkyl group and / or a fluorine atom is bonded to a carbon atom to which a hydroxyl group is bonded (here, the α-position carbon atom of the hydroxyalkyl group). Is preferred. In the fluorinated alkyl group bonded to the α-position, all of the hydrogen atoms of the alkyl group are preferably substituted with fluorine.

The “aliphatic cyclic group” in the “aliphatic cyclic group having a fluorinated hydroxyalkyl group” may be monocyclic or polycyclic.
In the structural unit (a31), the aliphatic cyclic group is preferably polycyclic.
Aliphatic cyclic groups include hydrocarbon groups consisting of carbon and hydrogen (alicyclic groups), and some of the carbon atoms constituting the ring of the alicyclic groups are oxygen atoms, nitrogen atoms, sulfur atoms, etc. Heterocyclic groups and the like substituted with heteroatoms are included. As the aliphatic cyclic group, an alicyclic group is preferable.
The aliphatic cyclic group may be either saturated or unsaturated, but is preferably saturated because it is highly transparent to ArF excimer laser and the like, and has excellent resolution and depth of focus (DOF). .
The aliphatic cyclic group preferably has 5 to 15 carbon atoms.

Specific examples of the aliphatic cyclic group include the following.
That is, examples of the monocyclic group include a group in which two or more hydrogen atoms are removed from a cycloalkane including a hydrogen atom substituted with a fluorinated hydroxyalkyl group (hereinafter the same). More specifically, a group in which two or more hydrogen atoms have been removed from cyclopentane or cyclohexane can be mentioned, and a group in which two hydrogen atoms have been removed from cyclohexane is preferred.
Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. More specifically, a group in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.
Such a polycyclic group is appropriately selected from those proposed as many constituting acid dissociable, dissolution inhibiting groups in, for example, resins for positive photoresist compositions for ArF excimer laser processes. Can be used.
Of these, groups in which two hydrogen atoms have been removed from cyclohexane, adamantane, norbornane, and tetracyclododecane are preferred because they are readily available in the industry.
Of these exemplified monocyclic groups and polycyclic groups, groups in which two hydrogen atoms have been removed from norbornane are particularly preferred.

  The structural unit (a31) is preferably a structural unit derived from acrylic acid, and in particular, the above fatty acid is bonded to the oxygen atom (—O—) of the carbonyloxy group [—C (O) O—] of the acrylate ester. A structure in which an aromatic cyclic group is bonded (a structure in which a hydrogen atom of a carboxy group of acrylic acid is substituted with the aliphatic cyclic group) is preferable.

  More specifically, as the structural unit (a31), a structural unit (a31-1) represented by general formula (a31-1) shown below is preferable.

［式中、Ｒ^４０は水素原子、ハロゲン原子、アルキル基又はハロゲン化アルキル基であり；ｓ、ｔ、ｔ’はそれぞれ独立して１〜５の整数である。］

[Wherein, R ⁴⁰ represents a hydrogen atom, a halogen atom, an alkyl group or a halogenated alkyl group; and s, t and t ′ each independently represents an integer of 1 to 5. ]

In formula (a31-1), R ⁴⁰ represents a hydrogen atom, a halogen atom, an alkyl group or a halogenated alkyl group.
Examples of the halogen atom for R ⁴⁰ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
The alkyl group represented by R ⁴⁰ is preferably a lower alkyl group having 5 or less carbon atoms. For example, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and an isopentyl group. And a neopentyl group, and a methyl group is preferable.
The halogenated alkyl group for R ⁴⁰ is preferably a group in which one or more hydrogen atoms of a lower alkyl group having 5 or less carbon atoms are substituted with a halogen atom. Specific examples of the alkyl group are the same as described above. The hydrogen atom substituted with a halogen atom may be a part or all of the hydrogen atoms constituting the alkyl group.
In the present embodiment, R ⁴⁰ is preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom or a methyl group in terms of industrial availability.
s is an integer of 1-5 independently, Preferably it is an integer of 1-3, and 1 is the most preferable.
t is an integer of 1 to 5, preferably an integer of 1 to 3, and 1 is most preferable.
t ′ is an integer of 1 to 3, preferably an integer of 1 to 2, and 1 is most preferable.
In the structural unit (a31-1) represented by the general formula (a31-1), a 2-norbornyl group or a 3-norbornyl group is bonded to the carboxy group of (α-lower alkyl) acrylic acid. It is preferable. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

The structural unit (a31) can be used alone or in combination of two or more.
In the component (A _N 2), the proportion of the structural unit (a31) is preferably 10 to 90 mol%, more preferably 20 to 90 mol%, based on the total of all the structural units constituting the (A _N 2) component. 40 to 90 mol% is particularly preferable, and 45 to 85 mol% is most preferable. The effect by containing a structural unit (a31) is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

Structural unit (a32)
The structural unit (a32) is a structural unit derived from an acrylate ester containing a hydroxyl group-containing aliphatic cyclic group. When the (A _N 2) component containing the structural unit (a32) is blended in the negative resist composition, the hydroxyl group (alcoholic hydroxyl group) of the structural unit (a32) acts as an acid generated from the component (B). The component (C) reacts with the component (C), whereby the component (A _N 2) is changed from a property soluble in an alkali developer to an insoluble property.

A “hydroxyl group-containing aliphatic cyclic group” is a group in which a hydroxyl group is bonded to an aliphatic cyclic group.
The number of hydroxyl groups bonded to the aliphatic cyclic group is preferably 1 to 3, more preferably 1.
The aliphatic cyclic group may be monocyclic or polycyclic, but is preferably a polycyclic group. Moreover, an alicyclic hydrocarbon group is preferable. Moreover, it is preferable that it is saturated. Moreover, it is preferable that carbon number of an aliphatic cyclic group is 5-15.
Specific examples of the aliphatic cyclic group (the state before the hydroxyl group is bonded) include the same aliphatic cyclic groups as those described above for the structural unit (a31).
As the aliphatic cyclic group of the structural unit (a32), among the above, a cyclohexyl group, an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are preferable because they are easily available in the industry. Of these, a cyclohexyl group and an adamantyl group are preferable, and an adamantyl group is particularly preferable.
In addition to the hydroxyl group, a linear or branched alkyl group having 1 to 4 carbon atoms may be bonded to the aliphatic cyclic group.

In the structural unit (a32), the hydroxyl group-containing aliphatic cyclic group is preferably bonded to the ester group (—C (O) O—) of the acrylate ester.
In this case, in the structural unit (a32), other substituents may be bonded to the α-position (α-position carbon atom) of the acrylate ester instead of the hydrogen atom. As the substituent, an alkyl group, a halogenated alkyl group, or a halogen atom is preferable. These explanations are the same as those of R ⁴⁰ in the general formula (a31-1) of the structural unit (a31), and among those that can be bonded to the α-position, a hydrogen atom or an alkyl group is preferable. In particular, a hydrogen atom or a methyl group is preferable, and a hydrogen atom is most preferable.

  As a specific example of the structural unit (a32), for example, a structural unit (a32-1) represented by general formula (a32-1) shown below is preferable.

［式中、Ｒ^４０は前記と同じであり；Ｒ^４１は水素原子、アルキル基、または炭素数１〜５のアルコキシ基であり；ｒは１〜３の整数である。］

[Wherein, R ⁴⁰ is the same as described above; R ⁴¹ is a hydrogen atom, an alkyl group, or an alkoxy group having 1 to 5 carbon atoms; and r is an integer of 1 to 3. ]

R ⁴⁰ is the same as described in the general formula (a31-1).
The alkyl group for R ⁴¹ is the same as the alkyl group for R ⁴⁰ .
In the general formula (a32-1), R ⁴⁰ and R ⁴¹ are most preferably a hydrogen atom.
r is an integer of 1 to 3, and is preferably 1.
The bonding position of the hydroxyl group is not particularly limited, but is preferably bonded to the 3rd position of the adamantyl group.

The structural unit (a32) can be used alone or in combination of two or more.
In the component (A _N 2), the proportion of the structural unit (a32) is preferably 10 to 70 mol%, more preferably 10 to 50 mol%, with respect to the total of all the structural units constituting the component (A _N 2). Preferably, 20-40 mol% is more preferable. The effect by containing a structural unit (a32) is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

Structural unit (a33)
In addition to the structural unit (a31) and the structural unit (a32), the component (A _N 2) is a structural unit that is further derived from acrylic acid having no cyclic structure and having an alcoholic hydroxyl group in the side chain. (A33).
When the (A _N 2) component having the structural unit (a33) is blended in the negative resist composition, the alcoholic hydroxyl group of the structural unit (a33) is combined with the hydroxyl group of the structural unit (a32) from the component (B). It reacts with the component (C) by the action of the generated acid.
Therefore, the (A _N 2) component is easily changed from a property soluble in an alkali developer to an insoluble property, and an effect of improving the resolution can be obtained. Moreover, film loss can be suppressed. Moreover, the controllability of the crosslinking reaction during pattern formation is improved. Furthermore, the film density tends to improve. Thereby, there exists a tendency for heat resistance to improve. Furthermore, etching resistance is also improved.

“Having no cyclic structure” means having no aliphatic cyclic group or aromatic group. The structural unit (a33) is clearly distinguished from the structural unit (a32) by not having a cyclic structure.
Examples of the structural unit having an alcoholic hydroxyl group in the side chain include a structural unit having a hydroxyalkyl group.
Examples of the hydroxyalkyl group include those similar to the hydroxyalkyl group in the “fluorinated hydroxyalkyl group” mentioned in the structural unit (a31).
For example, the hydroxyalkyl group may be directly bonded to the α-position carbon atom of the main chain (the portion where the ethylenic double bond of acrylic acid is cleaved), or may be substituted with the hydrogen atom of the carboxy group of acrylic acid. You may comprise ester. In the structural unit (a33), it is preferable that at least one or both of these be present.
When a hydroxyalkyl group is not bonded to the α-position, an alkyl group, a halogenated alkyl group, or a halogen atom may be bonded to the α-position carbon atom instead of the hydrogen atom. These are the same as those described for R ⁴⁰ in general formula (a31-1).

  As the structural unit (a33), the structural unit (a33-1) represented by the following general formula (a33-1) is preferable because of excellent effects of the present embodiment.

（式中、Ｒ^４２は水素原子、アルキル基、ハロゲン化アルキル基、ハロゲン原子またはヒドロキシアルキル基であり、Ｒ^４３は、水素原子、アルキル基、またはヒドロキシアルキル基であり、かつＲ^４２、Ｒ^４３の少なくとも一方はヒドロキシアルキル基である。）

Wherein R ⁴² is a hydrogen atom, an alkyl group, a halogenated alkyl group, a halogen atom or a hydroxyalkyl group, R ⁴³ is a hydrogen atom, an alkyl group or a hydroxyalkyl group, and R ⁴² , R ⁴³ At least one of them is a hydroxyalkyl group.)

The hydroxyalkyl group for R ⁴² is preferably a hydroxyalkyl group having 10 or less carbon atoms, desirably a linear or branched chain, more preferably a hydroxyalkyl group having 2 to 8 carbon atoms, Most preferred is a hydroxymethyl group or a hydroxyethyl group. The number of hydroxyl groups and the bonding position are not particularly limited, but it is usually one and preferably bonded to the end of the alkyl group.
The alkyl group in R ⁴² is preferably an alkyl group having 10 or less carbon atoms, more preferably an alkyl group having 2 to 8 carbon atoms, most preferably an ethyl group, a methyl group.
The halogenated alkyl group for R ⁴² is preferably a lower alkyl group having 5 or less carbon atoms (preferably an ethyl group or a methyl group), and part or all of the hydrogen atoms are substituted with halogen atoms (preferably fluorine atoms). Group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
^Examples of the alkyl group and hydroxyalkyl group for R ⁴³ include the same as the alkyl group and hydroxyalkyl group for R ⁴² .

As the structural unit represented by the general formula (a33-1), specifically, a structural unit derived from α- (hydroxyalkyl) acrylic acid (here, a structural unit derived from an acrylate ester is included). And a structural unit derived from an α- (hydroxyalkyl) acrylic acid alkyl ester and a structural unit derived from an (α-alkyl) acrylic acid hydroxyalkyl ester.
Among these, when the structural unit (a33) contains a structural unit derived from an α- (hydroxyalkyl) acrylic acid alkyl ester, it is preferable from the viewpoint of improving the effect and the film density, and among them, α- ( Structural units derived from hydroxymethyl) -acrylic acid ethyl ester or α- (hydroxymethyl) -acrylic acid methyl ester are preferred.
Moreover, when the structural unit (a33) includes a structural unit derived from (α-alkyl) acrylic acid hydroxyalkyl ester, it is preferable in terms of crosslinking efficiency. Among them, a structural unit derived from α-methyl-acrylic acid hydroxyethyl ester or α-methyl-acrylic acid hydroxymethyl ester is preferable.

The structural unit (a33) can be used alone or in combination of two or more.
In the component (A _N 2), the proportion of the structural unit (a33) is preferably from 5 to 50 mol%, more preferably from 5 to 40 mol%, based on the total of all structural units constituting the (A _N 2) component. Preferably, 5 to 30 mol% is particularly preferable, and 10 to 25 mol% is most preferable. The effect by containing a structural unit (a33) is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

-Other structural unit (A _N 2) component may have another structural unit which can be copolymerized as structural units other than each said structural unit (a31)-(a33).
As such a constitutional unit, a constitutional unit conventionally used for a known resin component for a chemically amplified resist composition can be used. For example, it is derived from an acrylate ester containing a lactone-containing monocyclic or polycyclic group. And a structural unit (a34).
When the lactone-containing monocyclic or polycyclic group of the structural unit (a34) is used for forming a resist film, it increases adhesion of the resist film to the substrate or increases hydrophilicity with the developer. It is effective. In addition, the effect of suppressing swelling is improved.
The lactone here refers to one ring containing the —O—C (O) — structure, and this is counted as the first ring. Therefore, when it has only a lactone ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.
In the structural unit (a34), one or more hydrogen atoms of the lactone-containing monocyclic or polycyclic group are substituted with a fluorinated hydroxyalkyl group.

As the structural unit (a34), any structural unit can be used without any particular limitation as long as it has a lactone ring having both the ester structure (—O—C (O) —) and a ring structure. is there.
Specifically, examples of the lactone-containing monocyclic group include groups in which one hydrogen atom has been removed from γ-butyrolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.

In the structural unit (a34), another substituent may be bonded to the α-position (the α-position carbon atom) instead of the hydrogen atom. As the substituent, an alkyl group, a halogenated alkyl group, or a halogen atom is preferable.
Description of these substituents is the same as the description of R ^{40 in} the general formula (a31-1) of the structural unit (a31), and among those capable of bonding to the α-position, a hydrogen atom or an alkyl is preferable. Of these, a hydrogen atom or a methyl group is particularly preferred, and a hydrogen atom is most preferred.

  More specifically, examples of the structural unit (a34) include structural units represented by general formulas (a34-1) to (a34-5) shown below.

（式中、Ｒ^４０は前記と同じである。Ｒ^４４はそれぞれ独立して水素原子、アルキル基、または炭素数１〜５のアルコキシ基であり、ｍ’は０または１の整数である。）

(In the formula, R ⁴⁰ is the same as described above. R ⁴⁴ is independently a hydrogen atom, an alkyl group, or an alkoxy group having 1 to 5 carbon atoms, and m ′ is an integer of 0 or 1.)

The alkyl group for R ⁴⁴ in formulas (a34-1) to (a34-5) is the same as the alkyl group for R in formula (a31-1). In general formulas (a34-1) to (a34-5), R ⁴⁴ is preferably a hydrogen atom in view of industrial availability.
As the structural unit (a34), units represented by general formulas (a34-2) to (a34-3) are most preferable.

As the structural unit (a34), one type may be used alone, or two or more types may be used in combination.
If the amount of the structural units (a34) to _(A N 2) component, the proportion of _(A N 2) structural units within the component (a34), based on the combined total of all structural units constituting the _(A N 2) component 10 to 70 mol% is preferable, 10 to 40 mol% is more preferable, and 10 to 25 mol% is most preferable. The effect by containing a structural unit (a34) is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

The (A _N 2) component is preferably a copolymer having the structural units (a31) to (a33) as main components.
Here, “main component” means that the total of the structural units (a31) to (a33) is 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more. . Most preferably, it is 100 mol%, and the (A _N 2) component is preferably a copolymer comprising the structural unit (a31), the structural unit (a32) and the structural unit (a33).

As the component (A _N 2), a component containing a combination of structural units such as the following formula (A1-11) is particularly preferable.

［式中、Ｒ^４０は前記と同じである。］

[Wherein, R ⁴⁰ is the same as defined above. ]

The mass average molecular weight (Mw; polystyrene-reduced mass average molecular weight by gel permeation chromatography) of the (A _N 2) component is preferably 2000 to 30000, more preferably 2000 to 10000, and still more preferably 3000 to 8000. By setting it within this range, a good dissolution rate in an alkali developer can be obtained, which is preferable from the viewpoint of high resolution. When the weight average molecular weight is lower within this range, good characteristics tend to be obtained.
Moreover, 1.0-5.0 are preferable and, as for dispersity (Mw / number average molecular weight (Mn)), 1.0-2.5 are more preferable.

The (A _N 2) component can be obtained, for example, by radical polymerization of a monomer for deriving each structural unit by a conventional method.

When the (A _N 2) component is used as the (A _N ) component, one or more of the above (A _N 2) components can be mixed and used.
Further, (A N ₂₎ in addition to components also other polymeric compounds known as a negative resist composition, for example hydroxystyrene resins, novolak resins, be contained in the acrylic resin (A _N) component Is also possible.
However, when using the _(A N 2) component, the proportion of _{(A N)} in the component _(A N 2) component is more preferably preferably at least 50 mass%, 70 mass% or more, It is particularly preferably 80% by mass or more, and most preferably 100% by mass.
In the negative resist composition of this embodiment, the content of the (A _N ) component may be adjusted according to the resist film thickness to be formed.

The component (B) in the present embodiment is the same as in the first embodiment.
The component (C) in the present embodiment is the same as that in the third embodiment.
In the negative resist composition of the present embodiment, the component (D) can be blended as in the first embodiment.
Further, as in the first embodiment, the negative resist composition of the present embodiment, which can contain an optional component such as the component (E), can be produced by dissolving the material in an organic solvent (S). it can. Examples of the component (S) are the same as those in the first embodiment. Especially, in this embodiment, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable, and PGME is more preferable.

The method of forming a resist pattern using the negative resist composition of the present embodiment can be performed by the same method as in the first embodiment, and a negative resist pattern is obtained.
In particular, the negative resist composition of this embodiment is suitable for ArF excimer laser.
According to this embodiment, the same effect as that of the third embodiment can be obtained.

  Examples of the present invention will be described below, but the scope of the present invention is not limited to these examples.

Synthesis Example 1: Synthesis of component (A _P 1) (1) Synthesis of resin 48 g of isopropyl alcohol, 0.4 g of 4-acetoxystyrene were added to a four-necked flask equipped with a nitrogen blowing tube, a reflux condenser, a dropping funnel and a thermometer. 0.04 g of styrene and 0.3 g of 2-adamantyloxymethyl methacrylate were added and purged with nitrogen, and then heated to 83 ° C. with stirring. While maintaining the temperature, 39 g of 4-acetoxystyrene, 4 g of styrene, 30 g of 2-adamantyloxymethyl methacrylate and 5 g of 2,2′-azobis- (2-methylbutyronitrile) were dissolved in 24 g of isopropyl alcohol. Was added dropwise over 3 hours. After completion of the dropping, stirring was continued for 3 hours while maintaining the temperature. Then, it cooled to 25 degreeC, the deposit was settled, the supernatant liquid was removed, and the sedimented deposit was melt | dissolved in 74 g of tetrahydrofuran. The 80% hydrazine aqueous solution 15g was dripped at the solution, and after stirring at 25 degreeC for 1 hour, reaction was complete | finished.
The obtained reaction solution was dropped into a large amount of water to obtain a precipitate. This precipitate was filtered, washed and dried to obtain a white solid random copolymer (hereinafter referred to as resin (A) -1).

(2) Identification of Resin (A) -1 The mass average molecular weight determined by gel permeation chromatography (GPC) in terms of polystyrene was 10,000, and the degree of dispersion was 1.70.
The composition ratio (molar ratio) of the structural units derived from each monomer by isotope carbon nuclear magnetic resonance ( ¹³ C-NMR) analysis was p-hydroxystyrene / styrene / 2-adamantyloxymethyl methacrylate = 65/10/25. It was.
The structure of Resin (A) -1 is shown below. In the following chemical formula, p / q / r = 65/10/25 [molar ratio].

Synthesis Example 2: Synthesis of component (A _P 2) (1) Synthesis of precursor polymer 141 g of isopropyl alcohol, 7 g of 4-acetoxystyrene and a 4-neck flask equipped with a nitrogen blowing tube, a reflux condenser, a dropping funnel and a thermometer After putting 3 g of 3-hydroxy-1-adamantyl-α-trifluoromethyl acrylate and replacing with nitrogen, the temperature was raised to 82 ° C. with stirring. While maintaining the temperature, 187 g of 4-acetoxystyrene, 84 g of 3-hydroxy-1-adamantyl-α-trifluoromethyl acrylate and 17 g of 2,2′-azobisisobutyronitrile were dissolved in 114 g of isopropyl alcohol. The solution was added dropwise over 3 hours. After completion of dropping, stirring was continued for 4 hours while maintaining the temperature.
Then, it cooled to 20 degreeC, the depositing deposit was settled, and after removing a supernatant liquid, 240 g of isopropyl alcohol was put, and it stirred and melt | dissolved at 75 degreeC. To the resulting solution, 9 g of 35 mass% hydrochloric acid and 43 g of water were added dropwise, stirred at 75 ° C. for 7 hours, and then cooled to 20 ° C. to complete the reaction.
2000 g of ethyl acetate is added to the obtained reaction solution, the ethyl acetate solution is washed with a large amount of water, the ethyl acetate is distilled off by atmospheric distillation, the precipitated white solid is dissolved in 1030 g of tetrahydrofuran, and the tetrahydrofuran solution of the precursor polymer is dissolved. 1237 g was obtained.

(2) Resin synthesis Into a four-necked flask equipped with a nitrogen blowing tube, a dropping funnel and a thermometer, 310 g of the tetrahydrofuran solution obtained above and 10 g of ethyl vinyl ether were added and stirred at 20 ° C., and p-toluenesulfonic acid was added thereto. -A catalytic amount of monohydrate was added and stirred for 4 hours while maintaining the temperature, and then the reaction was stopped by adding triethylamine.
The obtained reaction solution was dropped into a large amount of water to obtain a precipitate. This precipitate was filtered, washed and dried to obtain 55 g of a white solid random copolymer (resin (A) -2).

(4) Identification of Resin (A) -2 With respect to Resin (A) -2, the mass average molecular weight (Mw) determined in terms of polystyrene by gel permeation chromatography (GPC) is 10,000, and the dispersity (Mw / Mn ) Was 1.8.
As a result of isotope hydrogen nuclear magnetic resonance ( ¹ H-NMR) and isotope carbon nuclear magnetic resonance ( ¹³ C-NMR) analyses, resin (A) -2 has a structure represented by the following chemical formula and contains each structural unit. The ratio was a / b / c / d = 50/5/30/15 [molar ratio].

(Examples 1-6, Comparative Examples 1-5)
Each component shown in the following Table 1 was mixed and dissolved to prepare a resist composition solution. Examples 1 to 3 and Comparative Examples 1 and 2 are positive resist compositions, and Examples 4 to 6 and Comparative Examples 3 to 5 are negative resist compositions.
The meaning of each abbreviation in Table 1 is as follows. Moreover, the numerical value in [] is a compounding quantity (mass part). The amount of (B) -2 added was set to be equimolar with (B) -1.
(A) -1: Resin [(A _P 1) component] obtained in Synthesis Example 1 above.
(A) -2: Resin [(A _P 2) component] obtained in Synthesis Example 2 above.
(A) -3: p-hydroxystyrene / styrene = 78.5 / 21.5 (molar ratio), Mw 2500, Mw / Mn = 1.3, [(A _N 1) component].
(B) -1: a compound represented by the following chemical formula (B-0-1).
(B) -2: Triphenylsulfonium trifluoromethanesulfonate.
(C) -1: Bismethoxymethylurea N8314 (manufactured by Sanwa Chemical Co., Ltd.)
(C) -2: Hexamethoxymethylmelamine Mw30HM (manufactured by Sanwa Chemical Co., Ltd.).
(C) -3: Tetramethoxymethylated glycoluril MX270 (manufactured by Sanwa Chemical Co., Ltd.).
(D) -1: tri-n-octylamine.
(E) -1: salicylic acid.
(S) -1: PGMEA
(S) -2: PGME

  Each obtained resist composition solution was uniformly applied on an 8-inch silicon substrate subjected to hexamethyldisilazane treatment, and baked (PAB) for 90 seconds under the conditions shown in Table 1. A resist film was formed. The resulting resist film was drawn with an electron beam drawing machine (Hitachi HL-800D, 70 kV acceleration voltage) and baked (PEB) for 90 seconds under the conditions shown in Table 1. Then, after developing for 60 seconds with a 2.38 mass% TMAH aqueous solution at 23 ° C., rinsing with pure water for 30 seconds, and shaking and drying, a baking process is performed at 100 ° C. for 60 seconds to form a resist pattern. Formed.

<Evaluation of resolution>
For each of the positive resist compositions of Examples 1 to 3 and Comparative Examples 1 and 2, the sensitivity when a trench pattern having a width of 500 nm was formed was measured, and the limit resolution in the sensitivity was obtained.
About each negative resist composition of Examples 4-6 and Comparative Examples 3-5, the sensitivity at the time of 1: 1 500 nm line and space pattern formation was measured, and the limit resolution in this sensitivity was calculated | required.
The results are shown in Table 1.

<Evaluation of pattern shape>
The cross-sectional shape of the obtained resist pattern was observed with a scanning electron microscope (SEM). As a result, in Examples 1 to 6, a highly perpendicular shape was obtained. On the other hand, in Comparative Example 1, the opening tends to be narrower than the bottom of the trench, and in Comparative Example 2, the dissolution at the bottom of the trench is insufficient and the pattern is not completely removed. It was.
In Comparative Examples 3 to 5, when (B) -2 was added as component (B) in an equimolar amount to (B) -1 in Examples 4 to 6, the resist pattern was the same as in Examples 4 to 6. It was not resolved.

From these results, Examples 1 to 6 according to the present invention provide a resist pattern with good perpendicularity, which improves the resolution as compared with each comparative example using a conventional acid generator, and is finer. It was recognized that a resist pattern could be formed.
In contrast to the negative resist compositions of Comparative Examples 3 to 5 using the conventional acid generator (B) -2, the acid generator (B) -1 according to the present invention was not resolved. In the negative resist compositions of Examples 4 to 6 added in an equimolar amount with the (B) -2, good resolution was obtained. Therefore, the acid generator according to the present invention is a negative resist composition. It can be seen that there is little adverse effect on the dissolution rate during development.

Claims (5)

A resist composition comprising (A) a resin component whose alkali solubility is changed by the action of an acid, and (B) an acid generator component that generates an acid upon exposure,
The component (B) is represented by the following general formula (B-0)

[Wherein, R ⁰ represents an alkyl group or an alkoxy group; X represents a halogenated alkyl group; a is an integer of 0 to 3; and when a is 2 or 3, R ⁰ may be the same as each other. May be different. ]
The resist composition characterized by including the compound (B0) represented by these. The resist composition according to claim 1, wherein the component (A) is a resin component having an (A _P ) acid dissociable, dissolution inhibiting group and increasing alkali solubility by the action of an acid. The resist composition according to claim 1, wherein the component (A) is an (A _N ) alkali-soluble resin component, and further includes (C) a crosslinking agent component.   Furthermore, the resist composition as described in any one of Claims 1-3 containing a nitrogen-containing organic compound (D). A step of forming a resist film on a substrate using the resist composition according to claim 1, a step of selectively exposing the resist film, and an alkali developing of the resist film to form a resist A resist pattern forming method including a step of forming a pattern.