JP2009042752A - Surface treating agent for pattern formation and pattern forming method using the treating agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treating agent for performing the chemical treatment for a first resist pattern to satisfy the requirements that the first resist pattern is not dissolved in a second resist solution, the dimensions of the first resist pattern do not change, and the first resist pattern and the second resist pattern have the same dry etching resistance, in a freezing process in which chemical treatment is performed for the first resist pattern to thereby change the property thereof not to dissolve in a second resist solution, and to provide a pattern forming method using it. <P>SOLUTION: The surface treating agent contains at least one compound having at least one structure in which adjacent carbon atoms on a benzene ring have a group expressed by X and a group expressed by -CH<SB>2</SB>-OR<SB>1</SB>(X indicates univalent organic group, hydroxyl group, amino group or mercapto group. R<SB>1</SB>indicates a hydrogen atom or univalent organic group), and the pattern forming method uses the surface treating agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a surface treatment agent for forming a resist pattern used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and other photofabrication lithography processes, and a pattern using the same. The present invention relates to a forming method.
In particular, the present invention relates to a surface treatment agent for forming a resist pattern suitable for exposure by an immersion type projection exposure apparatus using far ultraviolet light having a wavelength of 200 nm or less as a light source and a pattern forming method using the same.

  Since the resist for KrF excimer laser (248 nm), an image forming method called chemical amplification has been used as an image forming method for a resist in order to compensate for sensitivity reduction due to light absorption. An example of a positive-type chemical amplification image forming method will be described. When exposed, the acid generator in the exposed area decomposes to generate an acid, and the acid generated in the exposure bake (PEB) is a reaction catalyst. Is used to change an alkali-insoluble group to an alkali-soluble group, and an exposed portion is removed by alkali development.

With the miniaturization of semiconductor elements, the wavelength of an exposure light source has been shortened and the projection lens has a high numerical aperture (high NA). Currently, an exposure machine using an ArF excimer laser having a 193 nm wavelength as a light source has been developed. The degree of achievement of miniaturization of a semiconductor element can be expressed by resolving power, and can be expressed by the following equation as is generally well known.
(Resolving power) = k ₁ · (λ / NA)
Here, λ is the wavelength of the exposure light source, NA is the numerical aperture of the projection lens, and k ₁ is a coefficient related to the process.

As a technique for increasing the resolving power, a so-called immersion method in which a high refractive index liquid (hereinafter also referred to as “immersion liquid”) is filled between the projection lens and the sample has been proposed.
This “immersion effect” means that when λ ₀ is the wavelength of the exposure light in the air, n is the refractive index of the immersion liquid with respect to air, θ is the convergence angle of the light beam, and NA ₀ = sin θ. The above-described resolving power and depth of focus can be expressed by the following equations.
(Resolving power) = k ₁ · (λ ₀ / n) / NA ₀
That is, the immersion effect is equivalent to using an exposure wavelength having a wavelength of 1 / n. In other words, in the case of a projection optical system with the same NA, the depth of focus can be increased n times by immersion.
Further, as a technique for increasing the resolution, a pattern forming method using a special process has been proposed. This is equivalent to decreasing k ₁ in the above-described resolving power equation. One of them is a freezing process (Patent Document 1, Non-Patent Document 1).

  The freezing process is, for example, as described in Patent Document 1, in which a first resist pattern is formed on a first resist film, and a second resist film is formed on the first resist pattern. In the step of forming the second resist pattern, the first resist pattern is not dissolved in the second resist solution or mixed with the second resist film when forming the second resist film. It refers to a process for changing the properties of one resist pattern by chemical or physical treatment. By using this technique, it is possible to form a desired resist pattern by dividing it twice, and it is possible to realize double resolution as compared with a normal exposure process. Here, the first and second are the order of steps for forming the first and second layers as shown in FIG.

As a known example of the freezing process, Patent Document 1 described above can be cited. In this example, after forming the first resist pattern, the first resist pattern is irradiated with vacuum ultraviolet rays, and the first resist pattern is used as the second resist pattern. The properties of the first resist pattern are changed so as not to dissolve in the liquid. In this method, it is clearly shown in this known example that the dimension of the first resist pattern changes before and after the irradiation with vacuum ultraviolet rays. A measure is taken by correcting the dimension of one resist pattern. However, the amount of dimensional variation is expected to vary depending on the size of the resist pattern, and it is practically impossible to design a dimensional-corrected mask for an actual semiconductor device pattern in which patterns of various sizes and shapes exist. It is. Therefore, basic characteristics required for the freezing process include (i) that the first resist pattern does not dissolve in the second resist solution, and (ii) the first resist before and after the property change of the first resist pattern. It is necessary to make it compatible that the dimension of the pattern does not change. Further, usually, in a semiconductor circuit manufacturing process, a resist pattern is used as a mask to transfer a pattern onto a substrate by etching. At this time, it is required that all resist patterns have the same etching resistance in an arbitrary pattern. Accordingly, in the freezing process, (iii) the first resist pattern and the second resist pattern are required to have the same dry etching resistance, but materials and processes that satisfy all these three characteristics have not yet been found. It has not been issued.

JP 2005-197349 A J. Vac. Sci. Technol. B 4, 426 (1986)

  The present invention has been made in view of the above circumstances. To form a second resist pattern by forming a second resist film on the first resist pattern after forming the first resist pattern. In the freezing process in which the first resist pattern is chemically treated to change its properties so that it does not dissolve in the second resist solution, (i) the first resist pattern is transformed into the second resist solution. Does not dissolve and (ii) does not change the dimension of the first resist pattern, and (iii) satisfies all the requirements that the first resist pattern and the second resist pattern have the same dry etching resistance. , Surface treatment agent for freezing process for chemically treating the first resist pattern, and pattern forming method using the same To provide.

The above problem has been solved by the following configuration.
[1]
A surface treatment agent used in a pre-process for forming a second resist film by forming a second resist film on the first resist pattern after forming the first resist pattern, on the benzene ring A structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms (X represents a monovalent organic group, a hydroxyl group, an amino group, or a mercapto group. R ₁ represents And a hydrogen atom or a monovalent organic group.) A surface treatment agent for forming a resist pattern, comprising a compound having at least one.
[2]
A compound having at least one structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring is represented by the following general formula (1). The surface treatment agent for forming a resist pattern according to [1], which is a compound comprising:
General formula (1):

In the general formula (1), X represents a monovalent organic group, a hydroxyl group, an amino group, or a mercapto group.
When z = 1, A represents a hydrogen atom or a monovalent organic group.
When z is 2, A represents a single bond or a divalent organic group.
When z is 3 or more, A represents a z-valent organic group.
R ₁ represents a hydrogen atom or a monovalent organic group.
When z is 2 or more, a plurality of X, R ₁ and R ₂ may be the same or different.
R ₂ represents a monovalent organic group. However, A and R ₂ may be bonded to each other to form a ring.
When n is 2 or more, the plurality of R ₂ may be the same or different, and R ₂ may be bonded to each other to form a ring.
n represents an integer of 0 to 3. z represents an integer of 1 to 8.
[3]
A compound having at least one structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring, or represented by the general formula (1) The surface treatment agent for forming a resist pattern according to [1] or [2], wherein the compound is a compound represented by the following general formula (2).
General formula (2):

In the general formula (2), X represents a monovalent organic group, a hydroxyl group, an amino group, or a mercapto group.
When z = 1, A represents a hydrogen atom or a monovalent organic group.
When z is 2, A represents a single bond or a divalent organic group.
When z is 3 or more, A represents a z-valent organic group.
R ₁ represents a hydrogen atom or a monovalent organic group.
When zn is 2 or more, a plurality of X, R ₁ , R ₂ and R ₃ may be the same or different.
R ₂ represents a monovalent organic group. However, A and R ₂ may be bonded to each other to form a ring.
R ₃ represents a hydrogen atom or a monovalent organic group.
m represents an integer of 1 to 3. l represents an integer of 0-2. z represents an integer of 1 to 8.
[4]
In the compound represented by the general formula (1) or the general formula (2), z is 2 or more, [2] or [3], the resist pattern-forming surface treatment agent according to [2].
[5]
Furthermore, the organic solvent is contained, The surface treating agent for resist pattern formation in any one of [1]-[4] characterized by the above-mentioned.
[6]
A step of forming a first resist pattern using the first resist composition, a step of treating the resist pattern with the treating agent according to any one of [1] to [5], and the first resist pattern And a step of forming a second resist pattern using the second resist composition on the top.

  Resist pattern formation in which the first resist pattern and the second resist solution are incompatible, the first resist pattern and the second resist pattern have the same dry etching resistance, and the first resist pattern dimensions do not change before and after the freezing treatment Surface treatment agents and the like can be provided.

The treatment agent of the present invention will be described in detail below.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. . For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

<Surface treatment agent for resist pattern formation>
The surface treatment agent for forming a resist pattern of the present invention is used in a pre-process for forming a second resist pattern by forming a second resist film on the first resist pattern after forming the first resist pattern. A structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on a benzene ring (where X is a monovalent organic group, hydroxyl group) And R ₁ represents a hydrogen atom or a monovalent organic group (hereinafter also referred to as a compound of the present invention).

Examples of the monovalent organic groups (R ₁ ) and (X) in X and R ₁ include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkoxy group, and an alkoxycarbonylamino group. Can do.
Here, the alkyl group may have a substituent, and may have an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain. Specifically, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-dodecyl group, n-tetradecyl group, n-octadecyl group, etc. And a branched alkyl group such as isopropyl group, isobutyl group, t-butyl group, neopentyl group and 2-ethylhexyl group.
The cycloalkyl group may have a substituent, may be polycyclic, and may have an oxygen atom in the ring. Specific examples include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, and the like.
The aryl group may have a substituent, and examples thereof include a phenyl group and a naphthyl group.
The aralkyl group may have a substituent, and examples thereof include a benzyl group, a phenethyl group, a naphthylmethyl group, and a naphthylethyl group.
Examples of the alkenyl group include a group having a double bond at any position of the alkyl group and cycloalkyl group.
Examples of the alkoxy group in the alkoxy group and the alkoxycarbonylamino group include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, a pentyloxy group, a hexyloxy group, and a heptyloxy group.
Examples of the substituent that each organic group may have include, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxy group, a carbonyl group, a cycloalkyl group, an aryl group, an alkoxy group, an acyl group, an acyloxy group, An alkoxycarbonyl group, an aminoacyl group, etc. are mentioned. As for the cyclic structure in the aryl group, cycloalkyl group and the like, examples of the further substituent include an alkyl group. As for the aminoacyl group, examples of the further substituent include 1 or 2 alkyl groups.

X is preferably an electron donating group excluding a halogen atom. Here, the electron donating group represents a substituent in which the value of the Paramet effect of Hammett rule is negative. Specific examples of such substituents include methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, methoxy group, ethoxy group, methyl sulfide group, amino group, N, N-dimethylamino group, vinyl. Group, mercapto group, hydroxy group and the like. Most preferred is a hydroxy group.

R ₁ is preferably an alkyl group or cycloalkyl group having 1 to 10 carbon atoms, more preferably an alkyl group or cycloalkyl group having 1 to 4 carbon atoms, still more preferably a methyl group or hydrogen atom having 1 carbon atom. is there.

The molecular weight of the compound having at least one structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring is not particularly limited, but is preferably 100 It is -1000, Most preferably, it is 100-700. That is, the molecular weight is preferably 1000 or less, and more preferably 700 or less, from the viewpoint of suppressing the increase in size of the first resist pattern.

In the resist pattern forming surface treatment agent of the present invention, a group represented by X and a group represented by —CH ₂ —OR ₁ are bonded to adjacent carbon atoms on the benzene ring contained in one molecule of the compound. The number of structures is preferably 2 to 10.
By using a compound having a structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring, the same or different resins are crosslinked with a treating agent. As a result, dissolution of the first resist pattern in the second resist solution can be suppressed.
In addition, by setting the number of structures having a group represented by X and a group represented by —CH ₂ —OR ₁ to adjacent carbon atoms on the benzene ring within the above range, unreacted —CH The number of _2- OR ₁ can be suppressed, which is preferable.

Examples of the compound having a structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring include compounds represented by the following general formula (1). preferable.
General formula (1):

In the general formula (1), X represents a monovalent organic group, a hydroxyl group, an amino group, or a mercapto group.
When z = 1, A represents a hydrogen atom or a monovalent organic group.
When z is 2, A represents a single bond or a divalent organic group.
When z is 3 or more, A represents a z-valent organic group.
R ₁ represents a hydrogen atom or a monovalent organic group.
When z is 2 or more, a plurality of X, R ₁ and R ₂ may be the same or different.
R ₂ represents a monovalent organic group. However, A and R ₂ may be bonded to each other to form a ring.
When n is 2 or more, the plurality of R ₂ may be the same or different, and R ₂ may be bonded to each other to form a ring.
n represents an integer of 0 to 3. z represents an integer of 1 to 8.

In the general formula (1), z represents an integer of 1 to 8, preferably 2 or more and 4 or less, more preferably 2 or 3.
When z is 2 or more, the same or different resins can be crosslinked with a treating agent, and as a result, dissolution of the first resist pattern in the second resist solution can be suppressed.

  Moreover, it is preferable that General formula (1) has a methylol group and / or an alkyl methylol group, and the methylol group and / or alkyl methylol group are 4 or less in 1 molecule, and are unreacted methylol group and / or alkyl methylol group. The number can be suppressed, and the number of unreacted methylol groups or alkylmethylol groups at 3 or less can be further suppressed, which is preferable.

The monovalent organic groups (A), (X), (R ₁ ) and (R ₂ ) in A, X, R ₁ and R ₂ are the same as the monovalent organic group as R ₁ described above. Can be mentioned.

Examples of the divalent organic group (A) in A include a divalent organic group obtained by removing one arbitrary hydrogen atom in the monovalent organic group.
Examples of the z-valent organic group (A) in A include a z-valent organic group obtained by removing z-1 arbitrary hydrogen atoms in the monovalent organic group.
What is preferable as the organic group (A) is 0 to 30 except for the number of carbon atoms forming the ring, and more preferably 0 to 20. Furthermore, it is preferable that a part or all of the hydrogen atoms of the hydrocarbon group is substituted with a halogen atom in R ₃ .

X is preferably an electron donating group excluding a halogen atom. Here, the electron donating group represents a substituent in which the value of the Paramet effect of Hammett rule is negative. Specific examples of such substituents include methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, methoxy group, ethoxy group, methyl sulfide group, amino group, N, N-dimethylamino group, vinyl. Group, mercapto group, hydroxy group and the like. Most preferred is a hydroxy group.

R ₁ is preferably an alkyl group or a cycloalkyl group, more preferably an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms, still more preferably a methyl group or a hydrogen atom.

R ₂ is preferably a hydrogen atom.
Also, those having an aromatic ring in the structure of R ₂ are also preferred. For example, monocyclic aromatic benzene derivatives, compounds in which a plurality of aromatic rings are linked (naphthalene, anthracene, tetracene, etc.), non-benzene aromatic derivatives, etc. Examples of non-benzene aromatic derivatives include pyrrole Residues, furan residues, thiophene residues, indole residues, benzofuran residues, benzothiophene residues and the like can be mentioned.

In addition, as a compound having a structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring, a second resist for the first resist pattern is used. A compound represented by the general formula (2) is also preferable from the viewpoint of improving the coating property of the liquid.
General formula (2):

In the general formula (2), X represents a monovalent organic group, a hydroxyl group, an amino group, or a mercapto group.
When z = 1, A represents a hydrogen atom or a monovalent organic group.
When z is 2, A represents a single bond or a divalent organic group.
When z is 3 or more, A represents a z-valent organic group.
R ₁ represents a hydrogen atom or a monovalent organic group.
When z is 2 or more, a plurality of X, R ₁ , R ₂ and R ₃ may be the same or different.
R ₂ represents a monovalent organic group. However, A and R ₂ may be bonded to each other to form a ring.
R ₃ represents a hydrogen atom or a monovalent organic group.
m represents an integer of 1 to 3. l represents an integer of 0-2. z represents an integer of 1 to 8.

A, X, 1 monovalent organic group in R _{1, R 2} and _{R 3} (A), as _{(X), (R 1)} , (R 2) and _{(R 3)} is, R ₁ of formula (1) The same thing can be mentioned.
R ₃ is preferably an alkyl group or a cycloalkyl group, more preferably an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms, still more preferably a methyl group or a hydrogen atom.

From the viewpoint of storage stability, m is preferably 1 to 2, and more preferably 1.
l is preferably 0 to 1, and more preferably 0.

z is preferably 2 or more and 4 or less, and more preferably 2 or 3.
The general formula (2) preferably has a methylol group and / or an alkylmethylol group, and when the number of methylol groups and / or alkylmethylol groups in one molecule is 2 or more, the same or different resins can be treated with a treating agent. It can bridge | crosslink and, as a result, melt | dissolution to the 2nd resist liquid of a 1st resist pattern can be suppressed.

A compound having at least one structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring, general formula (1) or general formula (2) The amount of the compound represented by is preferably 0.1 to 100% by mass, more preferably 2 to 95% by mass, and still more preferably 5 to 90% by mass with respect to the total amount of the treating agent.

A compound having at least one structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring, the general formula (1) or the general formula Examples of the compound represented by (2) include compounds (A-01) to (A-19) and compounds (B-01) to (B-25), but are not limited thereto.

Compounds having at least one structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring, general formula (1) and general formula (2) The compound represented by may be a commercially available product or a compound synthesized by a known method. Commercially available products can be used as they are for the exemplified compounds (A-01) to (A-19) and the compounds (B-01) to (B-25).

  Furthermore, the treating agent of the present invention preferably contains an organic solvent for controlling the solubility of the first resist pattern. As such an organic solvent, any solvent can be used as long as it does not dissolve the first resist pattern and dissolves the compound represented by the formula (1). Here, when the first resist pattern is not dissolved, a line-and-space pattern having a film thickness of 0.2 μm and 200 nm is formed under the condition of 23 ° C., and the pattern dimensions are measured when the pattern is immersed in an organic solvent for 10 minutes. It shows that the variation and the variation in the height of the pattern are both within ± 5%. Examples of such solvents include alcohol solvents, fluorine solvents, saturated hydrocarbon solvents, and the like. Among these solvents, alcohol solvents are preferable from the viewpoint of solubility of the treatment agent. The water content of the solvent is preferably 40 mol% or less, more preferably 10 mol% or less, and still more preferably 5 mol% or less.

The alcohol solvent is preferably a monohydric alcohol from the viewpoint of environmental safety, storage stability, and safety to the human body. These can be used alone or in combination.
Specific examples of the monohydric alcohol include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, tert-pentyl alcohol, and n-hexyl. Alcohol, n-heptyl alcohol, 2-heptyl alcohol, n-octyl alcohol, n-decanol, 3-methyl-3-pentanol, 2,3-dimethyl-2-pentanol, 4-phenyl-2-methyl-2 -Hexanol, 1-phenyl-2-methyl-2-propanol, s-amyl alcohol, t-amyl alcohol, isoamyl alcohol, 2-ethyl-1-butanol, n-undecanol and the like.
Among them, the alcohol has preferably 5 to 11 carbon atoms, more preferably 7 to 9 carbon atoms. The number of carbon atoms is preferably 5 or more, and more preferably 7 or more in terms of suppression of solvent volatilization.

  Specific examples of the alcohol having 5 to 11 carbon atoms include tert-pentyl alcohol, n-hexyl alcohol, n-heptyl alcohol, 2-heptyl alcohol, n-octyl alcohol, n-decanol, and 3-methyl-3-pen. Examples include butanol, 2,3-dimethyl-2-pentanol, 2-ethyl-1-butanol, n-undecanol, and the like. Specific examples of the alcohol having 7 to 9 carbon atoms include n-heptyl alcohol, 2-heptyl alcohol, n-octyl alcohol, 3-methyl-3-pentanol, 2,3-dimethyl-2-pentanol, 2 -Ethyl-1-butanol and the like.

As the fluorine-based solvent, perfluoro-2-butyltetrahydrofuran, perfluorotetrahydrofuran, perfluorohexane, perfluoroheptane, perfluorotributylamine, perfluorotetrapentylamine, perfluorotetrahexylamine, or the like can be used. These organic solvents can be used alone or in combination. Moreover, 40-80 mass% is preferable, and, as for content of the fluorine in a molecule | numerator, More preferably, it is 50-80 mass%.
Among these, 7-12 are preferable and, as for carbon number of a fluorine-type solvent, More preferably, it is 9-12. 7 or more carbon atoms are preferable and 9 or more carbon atoms are more preferable in terms of suppression of volatilization of the solvent.
Specific examples of the fluorine-based solvent having 7 to 12 carbon atoms include perfluoro-2-butyltetrahydrofuran, perfluoroheptane, perfluorotributylamine and the like. Specific examples of the fluorine-based solvent having 9 to 11 carbon atoms include perfluorotributylamine.

Saturated hydrocarbon solvents include pentane, 2-methylbutane, 3-methylpentane, hexane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, octane, 2,2,4-trimethylpentane, 2,2 , 3-trimethylhexane, decane, undecane, dodecane, 2,2,4,6,6-pentamethylheptane, tridecane, pentadecane, tetradecane, hexadecane and the like can be used. These organic solvents can be used alone or in combination.
The saturated hydrocarbon solvent preferably has 6 to 10 carbon atoms, and more preferably 7 to 9 carbon atoms. 6 or more carbon atoms are preferable and 7 or more carbon atoms are more preferable in terms of suppression of volatilization of the solvent.
Specific examples of the saturated hydrocarbon solvent having 6 to 10 carbon atoms include hexane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, octane, 2,2,4-trimethylpentane, 2,2 , 3-trimethylhexane, nonane, decane and the like. Specific examples of the saturated hydrocarbon solvent having 7 to 9 carbon atoms include heptane, octane, 2,2,4-trimethylpentane, 2,2,3-trimethylhexane, and nonane.

  As long as the organic solvent does not dissolve the first resist pattern and dissolves the compound represented by the general formula (1) of the present invention, organic solvents other than alcohol solvents, fluorine solvents, saturated hydrocarbon solvents, etc. However, it is preferable to use 80% by mass or more, preferably 100% by mass of these solvents.

As the other organic solvent, any one or more of ester, ether, ketone, amide, aromatic hydrocarbon and cyclic ketone can be appropriately selected and used. For example, esters such as ethyl lactate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dimethyl glycol monoacetate monomethyl ether, monoethyl ether, or mono Examples thereof include ethers such as phenyl ether and derivatives thereof, cyclic ethers such as dioxane, and ketones such as acetone, methyl ethyl ketone, cyclohexanone, and 2-heptanone.

  The amount of the organic solvent used is not particularly limited as long as the compound represented by the general formula (1) is dissolved, but is usually 0 to 99% by mass, preferably 5 with respect to the compound represented by the general formula (1). It is -95 mass%, More preferably, it is 10-90 mass%.

Furthermore, in order to accelerate the reaction with the first resist pattern, the treating agent of the present invention may contain an acid, a compound that generates an acid by heating, or a base as necessary.
As the acid to be added, a low molecular acid such as carboxylic acid or sulfonic acid can be used. Preferably, a low molecular weight such as carboxylic acid partially fluorinated or sulfonic acid partially fluorinated. Examples include acids. Specific examples include trifluorobutanesulfonic acid, heptafluoropropanesulfonic acid, perfluorobenzenesulfonic acid, and the like.
As a compound that generates an acid by heating, various compounds known in this field can be used. Examples thereof include known compounds such as sulfonium salt type compounds, anilinium salt type compounds, pyridinium salt type compounds, phosphonium salt type compounds, iodonium salt type compounds. The counter anions of these onium salt type compounds include SbF ₆ ⁻ and BF ₄ ^−.
, AsF ₆ ⁻ , PF ₆ ⁻ , toluene sulfonate, triflate and the like. The temperature for generating the acid is usually 200 ° C. or lower, preferably 160 ° C. or lower.
The addition amount of the acid or the compound that generates acid by heating is generally 0.01 to 20% by mass, preferably 0.1 to 10% by mass, based on the total amount of the treatment agent.

As the base to be added, a low molecular base such as organic amines can be used, and preferably a tertiary amine is used. Specifically, trimethylamine, triethylamine, tripropylamine, tributylamine, triethanolamine, triisopropylamine, triisobutylamine, diisopropylethylamine, 2,3 ′-(p-tolylamino) diethanol, diazabicycloundecene, dia Examples include zabicyclononene.
The amount of the base or the compound that generates a base by heating is generally 0.01 to 20% by mass, preferably 0.1 to 10% by mass, based on the total amount of the treatment agent.

  Moreover, it is preferable that the processing agent of this invention contains various surfactant. As the surfactant, various surfactants known in the art can be used. For example, ionic or nonionic fluorine-based and / or silicon-based surfactants can be used. Examples of these fluorine and / or silicon surfactants include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, US Pat. No. 5,405,720, etc. The surfactants described in US Pat. Nos. 5,360,692, 5,529,881, 5,296,330, 5,346,098, 5,576,143, 5,294,511, and 5,824,451 can be mentioned. The following commercially available surfactants can also be used as they are.

Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431, 4430 (manufactured by Sumitomo 3M Co., Ltd.),
Megafac F171, F176, F189, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.) ), PF6320, PF6520 (manufactured by OMNOVA) or the like, or a silicon surfactant.
In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used.
These surfactants may be used alone or in several combinations.
The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the processing agent.
By adding a surfactant to the treatment agent, the coating property when applying the treatment agent is improved.

  If necessary, the treatment agent may further contain a photoacid generator, a photosensitizer, a freezing reaction accelerator other than the acid, a resin, and the like.

<First resist>
In the present invention, after forming the first resist pattern on the first resist film, the acid-catalyzed esterification reaction between the first resist and the treating agent containing the compound of the present invention is controlled, and the first resist It is important to change the properties so that the pattern is not dissolved in the second resist solution. Control of the esterification reaction can be achieved not only by changing the properties of the treatment agent, but also by changing the properties of the first resist and / or the process conditions when the treatment agent is applied.

  The first resist may be either a positive resist or a negative resist, but is preferably a positive resist for the purpose of improving the reactivity with the treatment agent. Here, “positive resist” refers to a resist in which an exposed portion is dissolved in a developer, and “negative resist” refers to a resist in which a non-exposed portion is dissolved in a developer. A positive resist generally uses a chemical reaction such as elimination of an atomic group protecting an alkali-soluble group in order to increase the solubility of an exposed portion in a developer. Employs bond formation between molecules such as cross-linking reaction and polymerization reaction.

  The positive resist is preferably a positive resist composition containing a resin that decomposes by the action of an acid and increases the solubility in an alkaline developer, and a compound that generates an acid upon irradiation with actinic rays or radiation.

[1] Resin (resin (A)) that is decomposed by the action of acid and increases its solubility in an alkaline developer
As the resin (A), in order to cause a reaction such as esterification with the surface treatment agent containing the compound of the present invention and to change the properties so as not to dissolve the first resist pattern in the second resist solution, It is preferable that a carboxyl group is generated by a chemical reaction during the process of forming the resist pattern. The resin containing a carboxyl group may be previously contained in the first resist before pattern formation.

Resin (A) is a resin whose solubility in an alkali developer increases by the action of an acid, and decomposes into the main chain or side chain of the resin or both the main chain and the side chain by the action of an acid and is soluble in alkali It is a resin having a group that generates a group (hereinafter also referred to as “acid-decomposable group”).
Examples of alkali-soluble groups include phenolic hydroxyl groups, carboxyl groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamide groups, sulfonylimide groups, (alkylsulfonyl)
(Alkylcarbonyl) methylene group, (alkylsulfonyl) (alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, A tris (alkylcarbonyl) methylene group, a tris (alkylsulfonyl) methylene group, etc. are mentioned.
Preferred alkali-soluble groups include carboxyl groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonic acid groups.
A preferable group as the acid-decomposable group is a group obtained by substituting the hydrogen atom of these alkali-soluble groups with a group capable of leaving with an acid.
Examples of the group leaving with an acid include -C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), -C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), -C (R ₀₁ ) (R ₀₂ ). ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.
The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group or the like. More preferably, it is a tertiary alkyl ester group.

  In the resin (A), the repeating unit having an acid-decomposable group is preferably a repeating unit represented by the following general formula (AI).

In general formula (AI),
Xa ₁ represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represents an alkyl group (straight or branched) or a cycloalkyl group (monocyclic or polycyclic).
At least two of Rx _{1 to} Rx ₃ may combine to form a cycloalkyl group (monocyclic or polycyclic).

Examples of the divalent linking group for T include an alkylene group, —COO—Rt— group, —O—Rt— group, and the like. In the formula, Rt represents an alkylene group or a cycloalkylene group.
T is preferably a single bond or a —COO—Rt— group. Rt is preferably an alkylene group having 1 to 5 carbon atoms, more preferably a —CH ₂ — group or a — (CH ₂ ) ₃ — group.
The alkyl group of Rx _{1 to} Rx ₃ is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group.
Examples of the cycloalkyl group represented by Rx _{1 to} Rx ₃ include monocyclic cycloalkyl groups such as cyclopentyl group and cyclohexyl group, polycyclic cycloalkyl groups such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group, and adamantyl group. Groups are preferred.
Examples of the cycloalkyl group formed by combining at least two of Rx _{1 to} Rx ₃ include a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, A polycyclic cycloalkyl group such as an adamantyl group is preferred.
It is preferable that Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ are bonded to form the above-described cycloalkyl group.
The atomic group may further have a substituent, and examples thereof include an alkyl group, a cycloalkyl group, an alkoxy group, a hydroxyl group, and a cyano group.

  As for the content rate of the repeating unit which has an acid-decomposable group, 20-50 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 25-45 mol%.

  Although the specific example of the repeating unit which has a preferable acid-decomposable group is shown below, this invention is not limited to this.

(In the above formulas, X _a1 has the same meaning as X _a1 in formula (AI).)

(In the above formulas, X _a1 has the same meaning as X _a1 in formula (AI).)

(In the above formulas, X _a1 has the same meaning as X _a1 in formula (AI).)

  The resin (A) preferably further has a repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group, and an alkali-soluble group.

The repeating unit having a lactone group that can be preferably contained in the resin (A) will be described.
Any lactone group can be used as long as it has a lactone structure, but it is preferably a 5- to 7-membered ring lactone structure, and forms a bicyclo structure or a spiro structure in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. It is more preferable to have a repeating unit having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). The lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and a specific lactone structure is used. This improves line edge roughness and development defects.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, the plural substituents (Rb ₂ ) may be the same or different, and the plural substituents (Rb ₂ ) may be bonded to form a ring. .

  Examples of the repeating unit having a lactone structure represented by any one of the general formulas (LC1-1) to (LC1-16) include a repeating unit represented by the following general formula (AI ′).

In general formula (AI ′),
Rb ₀ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms. Preferred substituents that the alkyl group represented by Rb ₀ may have include a hydroxyl group and a halogen atom. Examples of the halogen atom for Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Rb ₀ is preferably a hydrogen atom or a methyl group.
Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these. Preferably a single bond, -Ab ₁ -CO ₂ - is a divalent linking group represented by. Ab ₁
Is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene group.
V represents a group having a structure represented by any one of the general formulas (LC1-1) to (LC1-16).

  The repeating unit having a lactone group usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

  As for the content rate of the repeating unit which has a lactone group, 15-60 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 20-50 mol%, More preferably, it is 30-50 mol%.

  Specific examples of the repeating unit having a lactone group are listed below, but the present invention is not limited thereto.

  Particularly preferred repeating units having a lactone group include the following repeating units. By selecting an optimal lactone group, the pattern profile and the density dependency are improved.

The repeating unit having a hydroxyl group or a cyano group that can be preferably contained in the resin (A) will be described. When the resin (A) contains the repeating unit, the substrate adhesion and the developer affinity are improved. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group.
As the alicyclic hydrocarbon structure substituted with a preferred hydroxyl group or cyano group, partial structures represented by the following general formulas (VIIa) to (VIId) are preferred.

In general formulas (VIIa) to (VIIc),
R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R ₂ c to R ₄ c represents a hydroxyl group or a cyano group. Preferably, one or two of R ₂ c to R ₄ c are a hydroxyl group and the remaining is a hydrogen atom. In general formula (VIIa), more preferably, _two of R ₂ c to R ₄ c are hydroxyl groups and the remaining are hydrogen atoms.

  Examples of the repeating unit having a partial structure represented by the general formulas (VIIa) to (VIId) include the repeating units represented by the following general formulas (AIIa) to (AIId).

In the general formulas (AIIa) to (AIId),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R ₂ c to R ₄ c are in the general formula (VIIa) ~ (VIIc), same meanings as R ₂ c~R ₄ c.

The content of the repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is
5-40 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 5-30 mol%, More preferably, it is 10-25 mol%.

The resin (A) preferably has a repeating unit represented by the general formula (II) as a repeating unit having a hydroxyl group.
When a treating agent containing the compound represented by the general formula (1) is applied on the pattern to form a coating film, if a reactive group such as a hydroxyl group is present, it is adsorbed thereto. Thereby, the hydroxyl group formed after hydrolysis reacts with the reactive group on the surface, and the adhesion between the coating film and the pattern surface is greatly improved.
General formula (II):

In the general formula (II), R ′ represents a hydrogen atom, an alkyl group (lower alkyl group, for example, having 1 to 4 carbon atoms), or a halogen atom.
l represents an integer of 1 to 2; Preferably it is 2.

  Specific examples of the repeating unit having a hydroxyl group or a cyano group are given below, but the present invention is not limited thereto.

The repeating unit having an alkali-soluble group that can be preferably contained in the resin (A) will be described. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulsulfonylimide group, and an aliphatic alcohol (for example, hexafluoroisopropanol group) substituted with an electron-attracting group at the α-position. It is more preferable to have a repeating unit. By containing the repeating unit having an alkali-soluble group, the resolution in contact hole applications is increased. The repeating unit having an alkali-soluble group includes a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or an alkali in the main chain of the resin through a linking group. Either a repeating unit to which a soluble group is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is used at the time of polymerization and introduced at the end of the polymer chain, and the linking group is monocyclic or polycyclic. It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

  As for the content rate of the repeating unit which has an alkali-soluble group, 0-25 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 3-20 mol%, More preferably, it is 5-15 mol%.

  Specific examples of the repeating unit having an alkali-soluble group are shown below, but the present invention is not limited thereto.

  The resin (A) may further have a repeating unit that has an alicyclic hydrocarbon structure and does not exhibit acid decomposability. This can reduce elution of low molecular components from the resist film to the immersion liquid during immersion exposure, and is advantageous in terms of dry etching resistance. Specific examples include a repeating unit represented by the following general formula (III).

In general formula (III), R ₅ represents a hydrocarbon group having at least one cyclic structure and having neither a hydroxyl group nor a cyano group.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.

The cyclic structure possessed by R ₅ includes a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include cycloalkenyl having 3 to 12 carbon atoms such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like, and cycloalkyl groups having 3 to 12 carbon atoms and cyclohexenyl group. Groups. Preferable monocyclic hydrocarbon groups are monocyclic hydrocarbon groups having 3 to 7 carbon atoms, and more preferable examples include a cyclopentyl group and a cyclohexyl group.

The polycyclic hydrocarbon group includes a ring assembly hydrocarbon group and a bridged cyclic hydrocarbon group, and examples of the ring assembly hydrocarbon group include a bicyclohexyl group and a perhydronaphthalenyl group. As the bridged cyclic hydrocarbon ring, for example, bicyclic such as pinane, bornane, norpinane, norbornane, bicyclooctane ring (bicyclo [2.2.2] octane ring, bicyclo [3.2.1] octane ring, etc.) Hydrocarbon rings and tricyclic hydrocarbon rings such as homobredan, adamantane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [4.3.1.1 ^2,5 ] undecane ring, tetracyclo [ 4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, perhydro-1,4-
And tetracyclic hydrocarbon rings such as methano-5,8-methanonaphthalene ring. The bridged cyclic hydrocarbon ring includes a condensed cyclic hydrocarbon ring such as perhydronaphthalene (decalin), perhydroanthracene, perhydrophenanthrene, perhydroacenaphthene, perhydrofluorene, perhydroindene, perhydroindene. A condensed ring in which a plurality of 5- to 8-membered cycloalkane rings such as a phenalene ring are condensed is also included.

Preferred examples of the bridged cyclic hydrocarbon ring include a norbornyl group, an adamantyl group, a bicyclooctanyl group, a tricyclo [5,2,1,0 ^2,6 ] decanyl group, and the like. More preferable examples of the bridged cyclic hydrocarbon ring include a norbornyl group and an adamantyl group.

  These alicyclic hydrocarbon groups may have a substituent, and preferred substituents include a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino group protected with a protecting group, and the like. It is done. Preferred halogen atoms include bromine, chlorine and fluorine atoms, and preferred alkyl groups include methyl, ethyl, butyl and t-butyl groups. The above alkyl group may further have a substituent, and the substituent which may further have a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino protected with a protecting group The group can be mentioned.

  Examples of the protecting group include an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an acyl group, an alkoxycarbonyl group, and an aralkyloxycarbonyl group. Preferred alkyl groups include alkyl groups having 1 to 4 carbon atoms, preferred substituted methyl groups include methoxymethyl, methoxythiomethyl, benzyloxymethyl, t-butoxymethyl, 2-methoxyethoxymethyl groups, and preferred substituted ethyl groups. 1-ethoxyethyl, 1-methyl-1-methoxyethyl, preferred acyl groups include formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, pivaloyl groups, etc., aliphatic acyl groups having 1 to 6 carbon atoms, alkoxycarbonyl Examples of the group include an alkoxycarbonyl group having 1 to 4 carbon atoms.

The content of the repeating unit represented by the general formula (III) having neither a hydroxyl group nor a cyano group is preferably from 0 to 40 mol%, more preferably based on all repeating units in the resin (A). 0 to 20 mol%.
Specific examples of the repeating unit represented by the general formula (III) are shown below, but the present invention is not limited thereto.

  Resin (A) adjusts dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and resolution, heat resistance, sensitivity, etc., which are general required characteristics of resist, in addition to the above repeating structural units. For this purpose, various repeating structural units can be included.

  Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.

Thereby, the performance required for the resin (A), in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Fine adjustment such as dry etching resistance can be performed.

  As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc.

  In addition, any addition-polymerizable unsaturated compound that can be copolymerized with monomers corresponding to the above various repeating structural units may be copolymerized.

  In the resin (A), the molar ratio of each repeating structural unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and the general required performance of the resist, resolving power, heat resistance, sensitivity. It is set appropriately in order to adjust etc.

  When the positive resist composition of the present invention is for ArF exposure, the resin (A) preferably has no aromatic group from the viewpoint of transparency to ArF light.

  The resin (A) is preferably one in which all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units are methacrylate repeating units, all of the repeating units are acrylate repeating units, or all of the repeating units are methacrylate repeating units and acrylate repeating units. Although it can be used, the acrylate-based repeating unit is preferably 50 mol% or less of the total repeating units. More preferably, the (meth) acrylate repeating unit having an acid-decomposable group represented by the general formula (AI) is 20 to 50 mol%, the (meth) acrylate repeating unit having a lactone group is 20 to 50 mol%, It is a copolymer having 5 to 30 mol% of (meth) acrylate-based repeating units having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and further containing 0 to 20 mol% of other (meth) acrylate-based repeating units. .

  When the positive resist composition of the present invention is irradiated with KrF excimer laser light, electron beam, X-ray, high energy light beam (EUV, etc.) having a wavelength of 50 nm or less, the resin (A) is represented by the general formula (AI). In addition to the repeating unit represented, it is preferable to further have a hydroxystyrene-based repeating unit. More preferably, it has a hydroxystyrene-based repeating unit, a hydroxystyrene-based repeating unit protected with an acid-decomposable group, and an acid-decomposable repeating unit such as a (meth) acrylic acid tertiary alkyl ester.

  Preferred examples of the repeating unit having an acid-decomposable group include t-butoxycarbonyloxystyrene, 1-alkoxyethoxystyrene, a repeating unit of (meth) acrylic acid tertiary alkyl ester, and the like. The repeating unit by 2-adamantyl (meth) acrylate and dialkyl (1-adamantyl) methyl (meth) acrylate is more preferable.

Resin (A) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the positive resist composition of the present invention. Thereby, the generation of particles during storage can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

  After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

  The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer, and may be a hydrocarbon, halogenated hydrocarbon, nitro, depending on the type of polymer. A compound, ether, ketone, ester, carbonate, alcohol, carboxylic acid, water, a mixed solvent containing these solvents, and the like can be appropriately selected for use. Among these, as a precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable.

  The amount of the precipitation or reprecipitation solvent used can be appropriately selected in consideration of efficiency, yield, and the like, but generally 100 to 10000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymer solution, More preferably, it is 300-1000 mass parts.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

The resin may be once deposited and separated, and then dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent. That is, after the polymerization reaction is completed, a solvent in which the polymer is hardly soluble or insoluble is contacted to precipitate the resin (step a), the resin is separated from the solution (step b), and the resin solution A is dissolved again in the solvent. Preparation (step c), and then contacting the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably a volume amount not more than 5 times). It may be a method including depositing a resin solid (step d) and separating the deposited resin (step e).

The weight average molecular weight of the resin (A) is preferably 1,000 to 200,000, more preferably 2,000 to 20,000, and even more preferably 3,000 to 15 in terms of polystyrene by GPC method. 1,000, particularly preferably 3,000 to 10,000. The weight average molecular weight is preferably 1,000 to 200,000 from the viewpoint of preventing deterioration of heat resistance and dry etching resistance and preventing deterioration of developability and film forming property due to an increase in viscosity.
The degree of dispersion (molecular weight distribution) is usually 1 to 3, preferably 1 to 2.6, more preferably 1 to 2, and particularly preferably 1.4 to 1.7. The smaller the molecular weight distribution, the better the resolution and the resist shape, and the smoother the side wall of the resist pattern, the better the roughness.

In the positive resist composition of the present invention, the blending ratio of the resin (A) in the entire composition is preferably 50 to 99.9% by mass, more preferably 60 to 99.0% by mass in the total solid content. .
In the present invention, the resin (A) may be used alone or in combination.

  Hereinafter, although the specific example of the polymer which can be used for this invention is shown, this invention is not necessarily limited only to these.

The positive resist composition of the present invention preferably further contains a resin (B) having at least one of a fluorine atom and a silicon atom.
In particular, in the case of immersion exposure, the resin (B) is preferably contained, and the resin (HR) described later in the case of immersion exposure can also be preferably used.
The fluorine atom or silicon atom in the resin (B) may be contained in the main chain of the resin or may be substituted with a side chain.
The resin (B) is preferably a resin having an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom as a partial structure having a fluorine atom.
When the resin (B) has a fluorine atom, the content of the fluorine atom is preferably 5 to 80% by mass and more preferably 10 to 80% by mass with respect to the molecular weight of the resin (B). Moreover, it is preferable that the repeating unit containing a fluorine atom is 10-100 mass% in resin (B), and it is more preferable that it is 30-100 mass%.

The resin (B) is preferably a resin having an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure as a partial structure having a silicon atom.
When the resin (B) has a silicon atom, the content of the silicon atom is preferably 2 to 50% by mass and more preferably 2 to 30% by mass with respect to the molecular weight of the resin (B). Moreover, it is preferable that it is 10-100 mass% in resin (B), and, as for the repeating unit containing a silicon atom, it is more preferable that it is 20-100 mass%.

Specific examples of the resin (B) are shown below, but the present invention is not limited thereto.
In the following (T-01) and (T-04), X represents a hydrogen atom, a methyl group, a fluorine atom, or a trifluoromethyl group.

The resin (B) is preferably stable to an acid and insoluble in an alkaline developer.
Resin (B) is decomposed by the action of (x) an alkali-soluble group, (y) an alkali (alkali developer), a group that increases the solubility in the alkali developer, and (z) an acid. From the viewpoint of the followability of the immersion liquid, it is preferable not to have a group that increases the solubility in the developer.
The total amount of repeating units having an alkali-soluble group in the resin (B) or a group whose solubility in a developer is increased by the action of an acid or alkali is preferably 20 with respect to all the repeating units constituting the resin (B). It is not more than mol%, more preferably 0 to 10 mol%, still more preferably 0 to 5 mol%.

In addition, the resin (B) does not have a hydrophilic group such as an ionic bond or a (poly (oxyalkylene)) group unlike a surfactant generally used in a resist. When the resin (B) contains a hydrophilic polar group, the followability of immersion water tends to decrease, and therefore it is more preferable that the resin (B) does not have a polar group selected from a hydroxyl group, an alkylene glycol, and a sulfone group. . In addition, it is preferable not to have an ether group bonded to a carbon atom of the main chain through a linking group because hydrophilicity increases and immersion liquid followability deteriorates. On the other hand, an ether group directly bonded to a carbon atom of the main chain is preferable because a hydrophobic group may be expressed.

  The weight average molecular weight in terms of standard polystyrene of the resin (B) is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, still more preferably 2,000 to 15,000, and particularly preferably. Is 3,000 to 15,000.

  Resin (B) preferably has a residual monomer amount of 0 to 10% by mass, more preferably 0 to 5% by mass, and still more preferably 0 to 1% by mass. The molecular weight distribution (Mw / Mn, also referred to as dispersity) is preferably 1 to 5, more preferably 1 to 3, and still more preferably 1 in terms of resolution, resist shape, resist pattern sidewall, roughness, and the like. It is in the range of ~ 1.5.

The addition amount of the resin (B) in the positive resist composition is preferably 0.1 to 20% by mass, and preferably 0.1 to 10% by mass based on the total solid content of the resist composition. Is more preferable. Furthermore, it is preferable that it is 0.1-5 mass%, More preferably, it is 0.2-3.0 mass%, More preferably, it is 0.3-2.0 mass%.
Various commercially available products can be used as the resin (B), and the resin (B) can be synthesized according to a conventional method (for example, radical polymerization).

[2] Compound that generates acid upon irradiation with actinic ray or radiation The positive resist composition of the present invention contains a compound that generates acid upon irradiation with actinic ray or radiation (hereinafter also referred to as “acid generator”). To do.

  As an acid generator, photo-initiator of photocation polymerization, photo-initiator of photo-radical polymerization, photo-decoloring agent of dyes, photo-discoloring agent, or irradiation with actinic ray or radiation used for micro-resist etc. Known compounds that generate acids and mixtures thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, such as US Pat. No. 3,849,137, German Patent No. No. 3914407, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, The compounds described in JP-A-62-153853 and JP-A-63-146029 can be used.

Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712, etc. can also be used.
Preferred compounds among the acid generators include compounds represented by the following general formulas (ZI), (ZII), and (ZIII).

In the general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1 to 30, preferably 1
~ 20.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Z ⁻ represents a non-nucleophilic anion.

Examples of the non-nucleophilic anion as Z ⁻ include a sulfonate anion, a carboxylate anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methide anion.

  A non-nucleophilic anion is an anion that has an extremely low ability to cause a nucleophilic reaction, and is an anion that can suppress degradation over time due to an intramolecular nucleophilic reaction. This improves the temporal stability of the resist.

Examples of the sulfonate anion include an aliphatic sulfonate anion, an aromatic sulfonate anion, and a camphor sulfonate anion.
Examples of the carboxylate anion include an aliphatic carboxylate anion, an aromatic carboxylate anion, and an aralkylcarboxylate anion.

  The aliphatic moiety in the aliphatic sulfonate anion may be an alkyl group or a cycloalkyl group, preferably an alkyl group having 1 to 30 carbon atoms and a cycloalkyl group having 3 to 30 carbon atoms such as methyl. Group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group , Tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, boronyl group and the like.

  The aromatic group in the aromatic sulfonate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

The alkyl group, cycloalkyl group and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion include, for example, a nitro group, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), carboxyl group , Hydroxyl group, amino group, cyano group, alkoxy group (preferably having 1 to 15 carbon atoms), cycloalkyl group (preferably having 3 to 15 carbon atoms), aryl group (preferably having 6 to 14 carbon atoms), alkoxycarbonyl group ( Preferably 2 to 7 carbon atoms, acyl group (preferably 2 to 12 carbon atoms), alkoxycarbonyloxy group (preferably 2 to 7 carbon atoms), alkylthio group (preferably 1 to 15 carbon atoms), alkylsulfonyl group (Preferably 1 to 15 carbon atoms), alkyliminosulfonyl group (preferably 2 to 15 carbon atoms), ant Ruoxysulfonyl group (preferably having 6 to 20 carbon atoms), alkylaryloxysulfonyl group (preferably having 7 to 20 carbon atoms), cycloalkylaryloxysulfonyl group (preferably having 10 to 20 carbon atoms), alkyloxyalkyloxy group (Preferably having 5 to 20 carbon atoms), a cycloalkylalkyloxyalkyloxy group (preferably having 8 to 20 carbon atoms), and the like. About the aryl group and ring structure which each group has, an alkyl group (preferably C1-C15) can further be mentioned as a substituent.

  Examples of the aliphatic moiety in the aliphatic carboxylate anion include the same alkyl group and cycloalkyl group as in the aliphatic sulfonate anion.

  Examples of the aromatic group in the aromatic carboxylate anion include the same aryl group as in the aromatic sulfonate anion.

  The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylmethyl group.

  The alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion include, for example, the same halogen atom and alkyl as in the aromatic sulfonate anion Group, cycloalkyl group, alkoxy group, alkylthio group and the like.

Examples of the sulfonylimide anion include saccharin anion.
The alkyl group in the bis (alkylsulfonyl) imide anion and tris (alkylsulfonyl) methide anion is preferably an alkyl group having 1 to 5 carbon atoms, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl. Group, sec-butyl group, pentyl group, neopentyl group and the like. Examples of substituents for these alkyl groups include halogen atoms, alkyl groups substituted with halogen atoms, alkoxy groups, alkylthio groups, alkyloxysulfonyl groups, aryloxysulfonyl groups, cycloalkylaryloxysulfonyl groups, and the like. Alkyl groups substituted with fluorine atoms are preferred.
Examples of other non-nucleophilic anions include fluorinated phosphorus, fluorinated boron, and fluorinated antimony.

Examples of the non-nucleophilic anion of Z ⁻ include an aliphatic sulfonate anion in which the α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion substituted with a fluorine atom or a group having a fluorine atom, and an alkyl group. A bis (alkylsulfonyl) imide anion substituted with a fluorine atom and a tris (alkylsulfonyl) methide anion wherein an alkyl group is substituted with a fluorine atom are preferred. More preferably, the perfluoroaliphatic sulfonic acid anion having 4 to 8 carbon atoms, the benzenesulfonic acid anion having a fluorine atom, a bis (alkylsulfonyl) imide anion in which the alkyl group is substituted with a fluorine atom, and the alkyl group being substituted with a fluorine atom Tris (alkylsulfonyl) methide anion.

Examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include a compound (ZI-1) described later.
), (ZI-2) and (ZI-3).
In addition, the compound which has two or more structures represented by general formula (ZI) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

More preferable (ZI) components include compounds (ZI-1), (ZI-2), and (ZI-3) described below.
The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compounds, namely, compounds containing an arylsulfonium as a cation.

In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or R ₂₀₁
Some of to R ₂₀₃ is an aryl group and the remainder may be an alkyl group or a cycloalkyl group.

  Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, and aryldicycloalkylsulfonium compounds.

  The aryl group of the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

  The alkyl group or cycloalkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms and a cycloalkyl group having 3 to 15 carbon atoms, such as a methyl group, Examples thereof include an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

Aryl group, alkyl group of R ₂₀₁ to R _203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms) , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group may be substituted. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, more preferably carbon. These are an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in which R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group having no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.

The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, 2-oxocycloalkyl group, alkoxy group. A carbonylmethyl group, particularly preferably a linear or branched 2-oxoalkyl group.

The alkyl group and cycloalkyl group of R ₂₀₁ to R _203, preferably a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon Examples thereof include cycloalkyl groups of several 3 to 10 (cyclopentyl group, cyclohexyl group, norbornyl group). More preferred examples of the alkyl group include a 2-oxoalkyl group and an alkoxycarbonylmethyl group. More preferred examples of the cycloalkyl group include a 2-oxocycloalkyl group.

The 2-oxoalkyl group may be either linear or branched, and a group having> C = O at the 2-position of the above alkyl group is preferable.
The 2-oxocycloalkyl group is preferably a group having> C═O at the 2-position of the cycloalkyl group.

The alkoxy group in the alkoxycarbonylmethyl group is preferably an alkoxy group having 1 to 5 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group).
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

Next, the compound (ZI-3) will be described.
The compound (ZI-3) is a compound represented by the following general formula (ZI-3), and is a compound having a phenacylsulfonium salt structure.

In general formula (ZI-3),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
R _x and R _y each independently represents an alkyl group, a cycloalkyl group, an allyl group or a vinyl group.

Any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom and a sulfur atom. , An ester bond and an amide bond may be included. Examples of the group formed by combining any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y include a butylene group and a pentylene group.
Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as Z ^{− in} formula (ZI).

The alkyl group as R _{1c to} R _7c may be either linear or branched, for example, an alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 12 carbon atoms ( Examples thereof include a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, and a linear or branched pentyl group. Examples of the cycloalkyl group include cyclohexane having 3 to 8 carbon atoms. An alkyl group (for example, a cyclopentyl group, a cyclohexyl group) can be mentioned.

The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).

Preferably, any of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R _{1c to} R _5c. Is 2-15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group and cycloalkyl group as R _x and R _y include the same alkyl group and cycloalkyl group as in R _{1c to} R _7c , such as a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxy group. A carbonylmethyl group is more preferred.

Examples of the 2-oxoalkyl group and 2-oxocycloalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as in R _{1c to} R _5c .

R _x and R _y are preferably an alkyl group or cycloalkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more alkyl groups or cycloalkyl groups.

Next, general formulas (ZII) and (ZIII) will be described.
In general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.

Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group. Aryl group R ₂₀₄ to R ₂₀₇ represents an oxygen atom, a nitrogen atom, may be an aryl group having a heterocyclic structure having a sulfur atom and the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like.

The alkyl group and cycloalkyl group in R ₂₀₄ to R _207, preferably a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon Examples thereof include cycloalkyl groups of several 3 to 10 (cyclopentyl group, cyclohexyl group, norbornyl group).

Aryl group, alkyl group of R ₂₀₄ to R _207, cycloalkyl groups may have a substituent. Aryl group, alkyl group of R ₂₀₄ to R _207, the cycloalkyl group substituent which may be possessed by, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms ), An aryl group (for example, having 6 to 15 carbon atoms), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.
Z ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of Z ^{− in} formula (ZI).
Examples of the acid generator further include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI).

In general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₈ , R ₂₀₉ and R ₂₁₀ each independently represents an alkyl group, a cycloalkyl group or an aryl group.
A represents an alkylene group, an alkenylene group or an arylene group.
Among the acid generators, compounds represented by the general formulas (ZI) to (ZIII) are more preferable.

Further, the acid generator is preferably a compound that generates an acid having one sulfonic acid group or imide group, more preferably a compound that generates monovalent perfluoroalkanesulfonic acid, or a monovalent fluorine atom or fluorine atom. A compound that generates an aromatic sulfonic acid substituted with a group containing fluorinated acid, or a compound that generates a monovalent fluorine atom or imide acid substituted with a group containing a fluorine atom, and even more preferably, It is a sulfonium salt of a substituted alkanesulfonic acid, a fluorine-substituted benzenesulfonic acid, a fluorine-substituted imide acid or a fluorine-substituted methide acid. The acid generator that can be used is particularly preferably a fluorinated substituted alkane sulfonic acid, a fluorinated substituted benzene sulfonic acid or a fluorinated substituted imido acid whose pKa of the generated acid is pKa = -1 or less, and the sensitivity is improved. .
Among acid generators, particularly preferred examples are listed below, but the present invention is not limited thereto.

An acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the acid generator in the positive resist composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total solid content of the positive resist composition. Preferably it is 1-7 mass%.

[3] Basic Compound The positive resist composition of the present invention preferably contains a basic compound in order to reduce the change in performance over time from exposure to heating.
Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In general formulas (A) and (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (having a carbon number). 6-20), wherein R ²⁰¹ and R ²⁰² may combine with each other to form a ring.
About the said alkyl group, as an alkyl group which has a substituent, a C1-C20 aminoalkyl group, a C1-C20 hydroxyalkyl group, or a C1-C20 cyanoalkyl group is preferable.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.
The alkyl groups in the general formulas (A) and (E) are more preferably unsubstituted.

  Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds include imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole, and 2-phenylbenzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4,0. ] Undecar 7-ene etc. are mentioned. Examples of the compound having an onium hydroxide structure include tetrabutylammonium hydroxide, triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenylsulfonium hydroxide, tris ( and t-butylphenyl) sulfonium hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, 2-oxopropylthiophenium hydroxide, and the like. As the compound having an onium carboxylate structure, an anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, N-phenyldiethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.

Preferred examples of the basic compound further include an amine compound having a phenoxy group, an ammonium salt compound having a phenoxy group, an amine compound having a sulfonic acid ester group, and an ammonium salt compound having a sulfonic acid ester group.
As the amine compound, a primary, secondary or tertiary amine compound can be used, and an amine compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. The amine compound is more preferably a tertiary amine compound. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the amine compound has an cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 3 to 20 carbon atoms). Preferably C6-C12) may be bonded to a nitrogen atom. The amine compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

As the ammonium salt compound, a primary, secondary, tertiary, or quaternary ammonium salt compound can be used, and an ammonium salt compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the ammonium salt compound has a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group in addition to the alkyl group. (Preferably having 6 to 12 carbon atoms) may be bonded to a nitrogen atom. The ammonium salt compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group. Examples of the anion of the ammonium salt compound include halogen atoms, sulfonates, borates, and phosphates. Among them, halogen atoms and sulfonates are preferable. As the halogen atom, chloride, bromide, and iodide are particularly preferable. As the sulfonate, an organic sulfonate having 1 to 20 carbon atoms is particularly preferable. Examples of the organic sulfonate include alkyl sulfonates having 1 to 20 carbon atoms and aryl sulfonates. The alkyl group of the alkyl sulfonate may have a substituent, and examples of the substituent include fluorine, chlorine, bromine, alkoxy groups, acyl groups, and aryl groups. Specific examples of the alkyl sulfonate include methane sulfonate, ethane sulfonate, butane sulfonate, hexane sulfonate, octane sulfonate, benzyl sulfonate, trifluoromethane sulfonate, pentafluoroethane sulfonate, and nonafluorobutane sulfonate. Examples of the aryl group of the aryl sulfonate include a benzene ring, a naphthalene ring, and an anthracene ring. The benzene ring, naphthalene ring and anthracene ring may have a substituent, and the substituent is preferably a linear or branched alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms. Specific examples of the linear or branched alkyl group and cycloalkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, t-butyl, n-hexyl, cyclohexyl and the like. Examples of the other substituent include an alkoxy group having 1 to 6 carbon atoms, a halogen atom, cyano, nitro, an acyl group, and an acyloxy group.

The amine compound having a phenoxy group and the ammonium salt compound having a phenoxy group are those having a phenoxy group at the terminal opposite to the nitrogen atom of the alkyl group of the amine compound or ammonium salt compound. The phenoxy group may have a substituent. Examples of the substituent of the phenoxy group include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, a sulfonic acid ester group, an aryl group,
Examples thereof include an aralkyl group, an acyloxy group, and an aryloxy group. The substitution position of the substituent may be any of the 2-6 positions. The number of substituents may be any in the range of 1 to 5.
It is preferable to have at least one oxyalkylene group between the phenoxy group and the nitrogen atom. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

In the amine compound having a sulfonic acid ester group and the ammonium salt compound having a sulfonic acid ester group, the sulfonic acid ester group may be any of alkyl sulfonic acid ester, cycloalkyl group sulfonic acid ester, and aryl sulfonic acid ester. In the case of an alkyl sulfonate ester, the alkyl group has 1 to 20 carbon atoms. In the case of a cycloalkyl sulfonate ester, the cycloalkyl group has 3 to 20 carbon atoms. In the case of an aryl sulfonate ester, the aryl group has 6 carbon atoms. ~ 12 are preferred. Alkyl sulfonic acid ester, cycloalkyl sulfonic acid ester, and aryl sulfonic acid ester may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid. An ester group is preferred.
It is preferable to have at least one oxyalkylene group between the sulfonate group and the nitrogen atom. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

  These basic compounds are used alone or in combination of two or more.

  The usage-amount of a basic compound is 0.001-10 mass% normally on the basis of the total solid of a positive resist composition, Preferably it is 0.01-5 mass%.

  The mixing ratio of the acid generator and the basic compound in the composition is preferably acid generator / basic compound (molar ratio) = 2.5 to 300. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

[4] Surfactant The positive resist composition of the present invention preferably further contains a surfactant, and is a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, It is more preferable to contain either one or two or more surfactants having both fluorine atoms and silicon atoms.

When the positive resist composition of the present invention contains the above-described surfactant, a resist pattern with good adhesion and low development defects can be obtained with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. It becomes possible.
Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 58,244
The surfactant described in the specification of No. 51 can be mentioned, and the following commercially available surfactants can also be used as they are.

Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431, 4430 (manufactured by Sumitomo 3M Co., Ltd.),
Megafuck F171, F173, F176, F189, F113, F110, F177, F120, R08 (manufactured by Dainippon Ink and Chemicals), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass ( Co., Ltd.), Troisol S-366 (manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toagosei Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), Ftop EF121, EF122A, EF122B, RF122C, EF125M, EF135M, EF351, 352, EF801, EF802, EF601 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204G, 208, 230G, 204 , Mention may be made of 208D, 212D, 218D, the fluorine-based surfactant or silicone-based surfactants such as 222D ((KK) Neos). Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₃ F ₇ group and (poly (oxy) And a copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl aryl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopa Mite - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.

  These surfactants may be used alone or in several combinations.

  The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total solid content in the positive resist composition.

[5] Solvent Examples of the solvent that can be used in preparing the positive resist composition by dissolving the above-described components include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, Organic solvents such as alkyl alkoxypropionates, cyclic lactones (preferably having 4 to 10 carbon atoms), monoketone compounds that may contain rings (preferably having 4 to 10 carbon atoms), alkylene carbonates, alkyl alkoxyacetates, alkyl pyruvates, etc. Can be mentioned.

Examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Preferred examples include ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.
Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate.
Preferable examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.

  Examples of the cyclic lactone include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, and γ-octano. Preferred are iclactone and α-hydroxy-γ-butyrolactone.

Examples of the monoketone compound which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2 -Methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexen-2-one, -Penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3-methyl Cyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, 3-methylcyclo A preferred example is heptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
Examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-acetate. 2-propyl is preferred.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.
As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, acetic acid -2- (2-ethoxyethoxy) ethyl and propylene carbonate are mentioned.
In the present invention, the above solvents may be used alone or in combination of two or more.

In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.
Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.
Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.
The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.

  The solvent is preferably a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.

<Second resist>
As the second resist used to form the second resist pattern, those described as the first resist can be used as appropriate, but the first resist pattern and the second resist pattern are resistant to dry etching. From the viewpoint of making the same, the resin used for the second resist is preferably substantially the same as the resin used for the first resist. Furthermore, in order to form a substantially identical pattern between the first resist and the second resist with respect to an actual semiconductor device mask in which patterns of various sizes and shapes exist, Most preferably, the second resist is made of the same resist.

The esterification reaction between the treatment agent containing the compound of the present invention and the first resist can also be controlled by changing the process conditions when the treatment agent is allowed to act.
Hereinafter, processes used for forming the first resist pattern, freezing by chemical treatment of the first resist pattern, and forming the second resist pattern will be described.

<Formation of first resist pattern>
In the present invention, the first resist composition is filtered and then applied to a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon having a pore size of 0.1 μm or less, more preferably 0.05 μm or less, and still more preferably 0.03 μm or less.

The filtered resist composition is coated on a substrate (eg, silicon / silicon dioxide coating) used for the manufacture of precision integrated circuit elements by a suitable coating method such as a spinner or a coater, and dried to form a resist film. Form. Heating (pre-baking) is preferably performed in the drying stage. The film thickness is preferably adjusted in the range of 50 to 200 nm, more preferably in the range of 70 to 180 nm.
When applying a resist composition with a spinner, the rotation speed is 500-3000 rpm normally, Preferably it is 800-2000 rpm, More preferably, it is 1000-1500 rpm.

Before forming the resist film, an antireflection film may be coated on the substrate in advance.
As the antireflection film, any of an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon, and an organic film type made of a light absorber and a polymer material can be used. In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, AR-2, AR-3, AR-5 manufactured by Shipley, etc. may be used. it can.

[Dry exposure method]
The resist film is irradiated with actinic rays or radiation through a predetermined mask, preferably baked (heated), developed and rinsed. Thereby, a good pattern can be obtained.
Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 to 1. Far ultraviolet light having a wavelength of 200 nm, specifically, ArF excimer laser, F ₂ excimer laser, EUV (13 nm), and electron beam are preferable, and ArF excimer laser is more preferable.

[Immersion exposure]
In the case of immersion exposure, the resist film is exposed (immersion exposure) through an immersion liquid through a mask or the like for pattern formation. For example, the exposure is performed in a state where the space between the resist film and the optical lens is filled with the immersion liquid. After exposure, the resist film is washed as necessary. Subsequently, preferably, spinning is performed to remove the immersion liquid. Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, etc., preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 to 200 nm. In particular, ArF excimer laser, F ₂ excimer laser and EUV (13 nm) are preferable, and ArF excimer laser is more preferable.

The immersion liquid used for the immersion exposure will be described below.
The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has the smallest possible refractive index temperature change. In particular, when the exposure light source is an ArF excimer laser (wavelength 193 nm), in addition to the above-described viewpoints. From the viewpoint of easy availability and ease of handling, it is preferable to use water.

  When water is used as the immersion liquid, the surface tension of the water is decreased and the surface activity is increased, so that the resist layer on the wafer is not dissolved and the influence on the optical coating on the lower surface of the lens element can be ignored. An additive (liquid) may be added in a small proportion. The additive is preferably an aliphatic alcohol having a refractive index substantially equal to that of water, and specifically includes methanol, ethanol, isopropanol and the like. By such an additive, even if the additive component in water evaporates and the content concentration changes, the advantage that the refractive index change as the whole liquid can be made extremely small is obtained. On the other hand, when an opaque material or impurities whose refractive index is significantly different from that of water are mixed with 193 nm light, the optical image projected on the resist film is distorted. . Further, pure water filtered through an ion exchange membrane or the like may be used.

The electrical resistance of the immersion liquid such as water is desirably 18.3 MQcm or more, the TOC (organic substance concentration) is desirably 20 ppb or less, and deaeration treatment is desirably performed.
Moreover, it is possible to improve lithography performance by increasing the refractive index of the immersion liquid. From such a viewpoint, an additive for increasing the refractive index may be added to water, or heavy water (D ₂ O) may be used instead of water.

An immersion liquid poorly soluble film (hereinafter also referred to as “top coat”) may be provided between the resist film and the immersion liquid so that the resist film is not directly brought into contact with the immersion liquid. Functions necessary for the top coat are suitability for application to the upper layer of the resist (can be uniformly applied), transparency to radiation, particularly light having a wavelength of 193 nm, and poor solubility in immersion liquid.
From the viewpoint of transparency to light having a wavelength of 193 nm, the topcoat is preferably a polymer that does not contain an aromatic, and specifically, a hydrocarbon polymer, an acrylate polymer, polymethacrylic acid, polyacrylic acid, polyvinyl ether. , Silicon-containing polymers, fluorine-containing polymers, and the like.

  When peeling the top coat, a developer may be used, or a separate release agent may be used. As the release agent, a solvent having a small penetration into the resist is preferable. It is preferable that the peeling process can be performed with an alkali developer in that the peeling process can be performed simultaneously with the resist development process. From the viewpoint of peeling with an alkaline developer, the topcoat is preferably acidic, but may be neutral or alkaline from the viewpoint of non-intermixability with the resist.

In the case of immersion exposure, instead of the top coat or in combination with the top coat, a hydrophobic resin (HR) described later is added to the resist composition to form a resist film. Immersion exposure may be performed.
Thereby, hydrophobic resin (HR) is unevenly distributed in the resist film surface layer, and when the immersion medium is water,
When the resist film is formed, the receding contact angle of the resist film surface with respect to water can be improved, and the immersion water followability can be improved. The hydrophobic resin (HR) is a resin whose surface receding contact angle is improved by addition, and preferably a resin having at least one of a fluorine atom and a silicon atom. The receding contact angle of the resist film is preferably 60 ° to 90 °, more preferably 70 ° or more. The addition amount can be adjusted as appropriate so that the receding contact angle of the resist film falls within the above range, but is preferably 0.1 to 10% by mass, more preferably based on the total solid content of the resist composition. Is 0.1-5 mass%. Hydrophobic resin (HR) is unevenly distributed at the interface, but unlike a surfactant, it does not necessarily have a hydrophilic group in the molecule and does not contribute to uniform mixing of polar / nonpolar substances. May be.

  When the hydrophobic resin (HR) is a resin having at least one of a fluorine atom and a silicon atom, it is a resin having an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom. It is preferable.

The alkyl group having a fluorine atom (preferably having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms) is a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, It may have a substituent.
The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have another substituent.
Examples of the aryl group having a fluorine atom include those in which at least one hydrogen atom of an aryl group such as a phenyl group or a naphthyl group is substituted with a fluorine atom, and may further have another substituent.

  Preferred examples of the alkyl group having a fluorine atom, the cycloalkyl group having a fluorine atom, or the aryl group having a fluorine atom include groups represented by the following general formulas (F2) to (F4). The present invention is not limited to this.

In general formulas (F2) to (F4),
R _{57 to} R ₆₈ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{57 to} R ₆₁ , R _{62 to} R ₆₄ and R _{65 to} R ₆₈ is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom (preferably having a carbon number of 1 ~ 4). R _{57 to} R ₆₁ and R _{65 to} R ₆₇ are preferably all fluorine atoms. R ₆₂ , R ₆₃ and R ₆₈ are preferably an alkyl group (preferably having 1 to 4 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom, and preferably a perfluoroalkyl group having 1 to 4 carbon atoms. Further preferred. R ₆₂ and R ₆₃ may be connected to each other to form a ring.

Specific examples of the group represented by the general formula (F2) include a p-fluorophenyl group, a pentafluorophenyl group, and a 3,5-di (trifluoromethyl) phenyl group.

  Specific examples of the group represented by the general formula (F3) include trifluoromethyl group, pentafluoropropyl group, pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2 -Methyl) isopropyl group, nonafluorobutyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-t-butyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro (trimethyl) hexyl group, 2,2 1,3,3-tetrafluorocyclobutyl group, perfluorocyclohexyl group and the like. Hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2-methyl) isopropyl group, octafluoroisobutyl group, nonafluoro-t-butyl group and perfluoroisopentyl group are preferable, and hexafluoroisopropyl group and heptafluoroisopropyl group are preferable. Further preferred.

Specific examples of the group represented by the general formula (F4) include, for example, —C (CF ₃ ) ₂ OH, —C (C ₂ F ₅ ) ₂ OH, —C (CF ₃ ) (CH ₃ ) OH, -CH (CF ₃₎ OH and the like, -C (CF _{3) 2} OH is preferred.

The hydrophobic resin (HR) is preferably a resin having an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure as a partial structure having a silicon atom.
Specific examples of the alkylsilyl structure or the cyclic siloxane structure include groups represented by the following general formulas (CS-1) to (CS-3).

In general formulas (CS-1) to (CS-3),
R _{12 to} R ₂₆ each independently represents a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms).
L < ₃ > -L < ₅ > represents a single bond or a bivalent coupling group. As the divalent linking group, an alkylene group, a phenylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a urethane group, or a urea group is used alone or in combination of two or more groups. A combination is mentioned.
n represents an integer of 1 to 5.

  Furthermore, the hydrophobic resin (HR) may have at least one group selected from the following groups (x) to (z).

(X) an alkali-soluble group,
(Y) a group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer;
(Z) A group that decomposes by the action of an acid.

  (X) Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) ( Alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) And a group having a methylene group.

  Preferred alkali-soluble groups include fluorinated alcohol groups (preferably hexafluoroisopropanol), sulfonimide groups, and bis (carbonyl) methylene groups.

  Examples of the repeating unit having an alkali-soluble group (x) include a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a main group of the resin via a linking group. It is preferable to use a repeating unit in which an alkali-soluble group is bonded to the chain, and further introduce a polymerization initiator or chain transfer agent having an alkali-soluble group at the end of the polymer chain at the time of polymerization.

  The content of the repeating unit having an alkali-soluble group (x) is preferably from 1 to 50 mol%, more preferably from 3 to 35 mol%, still more preferably from 5 to 20 mol, based on all repeating units in the hydrophobic resin (HR). %.

  (Y) Examples of the group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer include a group having a lactone structure, an acid anhydride, an acid imide group, and the like, and preferably a lactone group It is.

  As the repeating unit having a group (y) that is decomposed by the action of an alkali developer and increases the solubility in the alkali developer, an alkali is added to the main chain of the resin, such as a repeating unit of an acrylate ester or a methacrylate ester. A polymerization initiator having a repeating unit to which a group (y) that decomposes by the action of the developer and increases the solubility in an alkali developer is bonded, or a group (y) that increases the solubility in an alkali developer And a chain transfer agent used at the time of polymerization are preferably introduced at the end of the polymer chain.

  The content of the repeating unit having a group (y) whose solubility in an alkali developer is increased is preferably 1 to 40 mol%, more preferably 3 to 30 mol, based on all repeating units in the hydrophobic resin (HR). %, More preferably 5 to 15 mol%.

  Specific examples of the repeating unit having a group (y) that increases the solubility in an alkali developer include those similar to the repeating unit having a lactone structure mentioned in the description of the first resist. it can.

  In the hydrophobic resin (HR), the repeating unit having a group (z) that is decomposed by the action of an acid is the same as the repeating unit having an acid-decomposable group described above for the first resist. Is mentioned. In the hydrophobic resin (HR), the content of the repeating unit having a group (z) that decomposes by the action of an acid is preferably 1 to 80 mol% with respect to all the repeating units in the hydrophobic resin (HR). More preferably, it is 10-80 mol%, More preferably, it is 20-60 mol%.

  The hydrophobic resin (HR) may further have a repeating unit represented by the following general formula (IV).

In general formula (IV),
R ₄ represents a group having an alkyl group, a cycloalkyl group, an alkenyl group, or a cycloalkenyl group.
L ₆ represents a single bond or a divalent linking group.

In the general formula (IV), the alkyl group of R ₄ is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.
The cycloalkyl group is preferably a cycloalkyl group having 3 to 20 carbon atoms.
The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms.
The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20 carbon atoms.
The divalent linking group of L ₆ is preferably an alkylene group (preferably having 1 to 5 carbon atoms) or an oxy group.

  When the hydrophobic resin (HR) has a fluorine atom, the fluorine atom content is preferably 5 to 80% by mass, and 10 to 80% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that the repeating unit containing a fluorine atom is 10-100 mass% in hydrophobic resin (HR), and it is more preferable that it is 30-100 mass%.

  When the hydrophobic resin (HR) has a silicon atom, the content of the silicon atom is preferably 2 to 50% by mass and preferably 2 to 30% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that it is 10-100 mass% in hydrophobic resin (HR), and, as for the repeating unit containing a silicon atom, it is more preferable that it is 20-100 mass%.

  The weight average molecular weight of the hydrophobic resin (HR) in terms of standard polystyrene is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and even more preferably 2,000 to 15,000. is there.

  As in the case of the resin (A), the hydrophobic resin (HR) preferably has 0 to 10% by mass of residual monomer and oligomer components, and more preferably has few impurities such as metals. 0-5 mass% and 0-1 mass% are still more preferable. Thereby, a resist having no change over time such as foreign matter in liquid or sensitivity can be obtained. The molecular weight distribution (Mw / Mn, also referred to as dispersity) is preferably in the range of 1 to 5, more preferably 1 to 3, and still more preferably from the viewpoints of resolution, resist shape, resist pattern sidewall, roughness, and the like. It is the range of 1-2.

  Various commercially available products can be used as the hydrophobic resin (HR), and the hydrophobic resin (HR) can also be synthesized according to a conventional method. The method for synthesizing and purifying the resin is the same as the method for the resin (A) used as the first resist and the second resist, which is decomposed by the action of an acid and increases the solubility in an alkaline developer. Is mentioned.

  Specific examples of the hydrophobic resin (HR) are shown below. The following table shows the molar ratio of repeating units in each resin (corresponding to each repeating unit in order from the left), weight average molecular weight, and degree of dispersion.

  After the dry exposure or immersion exposure, preferably post-baking (post-heating) is performed, followed by development and rinsing. Thereby, a good pattern can be obtained.

In the development step, an alkali developer is usually used. As an alkaline developer of the resist composition, inorganic hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide and the like Alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and pihelidine can be used.
Furthermore, alcohols and surfactants can be appropriately added to the alkaline developer for use.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass.
The pH of the alkali developer is usually from 10.0 to 15.0.

As the rinsing liquid, pure water is usually used, and an appropriate amount of a surfactant can be added and used.
Further, after the development process or the rinsing process, a process of removing the developer or the rinsing liquid adhering to the pattern with a supercritical fluid can be performed.
Further, after the rinsing process or the supercritical fluid process, a heat treatment can be performed to remove moisture remaining in the pattern.

<Chemical treatment of the first resist pattern>
After the first resist pattern is formed using the above method, the first resist pattern is chemically treated (freezing treatment) using the treating agent of the present invention.

[Washing with acid]
First, it is preferable to wash the first resist pattern with a solution containing an acid different from the treatment agent of the present invention. Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as carboxylic acid, sulfonic acid, sulfonylimide acid, and methide acid. Among these, carboxylic acid, sulfonic acid, and imide Organic acids such as acid and methide acid are preferred.
Examples of carboxylic acids include alkyl sulfonic acids such as acetic acid and propionic acid, fluoroalkyl carboxylic acids such as perfluoroalkyl carboxylic acids having 1 to 8 carbon atoms, and aromatic carboxylic acids such as benzoic acid and pentafluorobenzoic acid. .
Examples of the sulfonic acid include butanesulfonic acid, hexanesulfonic acid, alkylsulfonic acid such as C1-C8 perfluoroalkylsulfonic acid, and aromatic sulfonic acid such as p-toluenesulfonic acid and pentafluorobenzenesulfonic acid. It is done.
Examples of imido acids include bis (alkylsulfonyl) imidic acid having 1 to 8 carbon atoms, bis (perfluoroalkylsulfonyl) imidic acid having 1 to 8 carbon atoms, cyclic disulfonylimide acid having 5 to 8 members, and fluorination. Examples thereof include disulfonylimide acids such as 5- to 8-membered cyclic disulfonylimide acids having an alkylene chain.
Examples of the methide acid include trisulfonylmethide acids such as tris (alkylsulfonyl) methido acid having 1 to 8 carbon atoms and tris (fluoroalkylsulfonyl) methido acid having 1 to 8 carbon atoms.
Among these, perfluoroalkyl carboxylic acids, sulfonic acids, imide acids, and methide acids are preferable, and perfluoroalkyl sulfonic acids, aromatic sulfonic acids, imide acids, and methide acids are more preferable.

The solvent of the solution may be any solvent in which the resist pattern does not dissolve and the acids dissolve, and includes, for example, water and a solvent used in the treatment agent of the present invention, preferably a solvent used in the treatment agent of the present invention. Is used.
The concentration of the acid is generally from 0.1 to 10 mol%, preferably from 0.5 to 5 mol%, more preferably from 0.5 to 3 mol%.
As a preferred treatment method, an acid solution is padded on the substrate on which the first resist pattern is formed, and after a while, the substrate is rotated and shaken off, and the substrate is washed with a solvent.
The longer the contact time between the solution and the resist pattern after padding the solution is 5 seconds or longer, the better, but considering the throughput, it is preferably 3 minutes or less, more preferably 2 minutes or less, and 1 minute or less. Most preferred. Moreover, it is preferable to use the solvent used for the acid solution as the solvent for washing the substrate with a solvent in order to remove excess acid from the substrate.
In the cleaning method, the solvent is discharged at the center of the substrate at a flow rate of 0.5 to 5 ml / sec for 5 to 30 seconds while rotating the substrate at 50 to 500 rpm, and then the substrate is discharged at 500 to 3000 rpm for 10 to 60 seconds. Although the method of rotating and shaking off a solvent is preferable, it is not limited to this.

[Chemical treatment]
Next, a method for chemical treatment of the first resist pattern using the treating agent of the present invention will be described.
Examples of the method for bringing the treatment agent into contact with the resist pattern include a method of immersing the resist pattern in the treatment agent and a method of applying the treatment agent on the resist pattern.
As a method of immersing, a method of padding the treatment agent on the substrate on which the first resist pattern is formed is preferable.
The longer the time during which the processing agent is padded on the substrate and the processing agent is in contact with the resist pattern is longer than 5 seconds, it is better. However, considering the throughput, it is preferably 3 minutes or less, more preferably 2 minutes or less. Most preferred is 1 minute or less.
Moreover, although the temperature in a processing apparatus and the temperature of a processing agent can be made higher than room temperature in order to advance reaction, the temperature of 50 degrees C or less is preferable from a safety viewpoint.

After contacting the treatment agent, it is preferable to wash the substrate with a solvent in order to remove excess chemical species from the substrate. In this case, the solvent used in the treatment agent is preferably used. In the cleaning method, the solvent is discharged at the center of the substrate at a flow rate of 0.5 to 5 ml / sec for 5 to 30 seconds while rotating the substrate at 50 to 500 rpm, and then the substrate is discharged at 500 to 3000 rpm for 10 to 60 seconds. Although the method of rotating and shaking off a solvent is preferable, it is not limited to this.
In addition, spin coating is also preferable as a method for applying the treatment agent on the resist pattern.
In the case of spin coating, the solvent is discharged at the center of the substrate for 0.5 to 5 seconds at a flow rate of 0.5 to 5 ml / sec while rotating the substrate at 50 to 500 rpm, and then the substrate is 10 to 500 to 3000 rpm. It is preferable to spin off the solvent for 60 seconds to apply the treatment agent.
Also in this case, it is preferable to wash the substrate with a solvent in order to remove excess chemical species from the substrate. In this case, it is preferable to use the solvent used for the treating agent. In the cleaning method, the solvent is discharged at the center of the substrate at a flow rate of 0.5 to 5 ml / sec for 5 to 30 seconds while rotating the substrate at 50 to 500 rpm, and then the substrate is discharged at 500 to 3000 rpm for 10 to 60 seconds. Although the method of rotating and shaking off a solvent is preferable, it is not limited to this.

In the present invention, it is preferable to heat the substrate in order to advance the reaction between the treating agent of the present invention and the resist pattern.
The heating temperature is usually preferably 60 ° C. or higher and 200 ° C. or lower, more preferably 80 ° C. or higher and 180 ° C. or lower, most preferably 90 ° C. or higher and 150 ° C. or lower. The heating time is preferably from 10 seconds to 300 seconds, and more preferably from 30 seconds to 150 seconds.
After heating, the substrate is preferably cooled, and the substrate is preferably washed with a solvent in order to remove excess treatment agent and reaction by-products. In this case, it is preferable to use the solvent used for the treating agent or the solvent of the first resist.

In the cleaning method, the solvent is discharged at the center of the substrate at a flow rate of 0.5 to 5 ml / sec for 5 to 30 seconds while rotating the substrate at 50 to 500 rpm, and then the substrate is discharged at 500 to 3000 rpm for 10 to 60 seconds. Although the method of rotating and shaking off a solvent is preferable, it is not limited to this.
Furthermore, it is preferable to add a heating step in order to remove the cleaning solvent. The heating temperature is preferably 60 ° C. or higher and 200 ° C. or lower, more preferably 70 ° C. or higher and 170 ° C. or lower, and most preferably 80 ° C. or higher and 150 ° C. or lower. The heating time is preferably 30 seconds or longer and 120 seconds or shorter, and more preferably 40 seconds or longer and 100 seconds or shorter.

<Formation of second resist pattern>
In the present invention, the second resist composition is filtered and then applied to a substrate on which a first resist pattern that has already been chemically treated is formed. The filter filtration is the same as in the first resist pattern.

  The second resist composition is applied onto the first resist pattern that has been subjected to chemical treatment (freezing treatment) in the same manner as the formation of the first resist pattern to form a resist film. For the subsequent steps of forming the second resist pattern, such as drying (pre-baking), exposure, post-baking, development, and rinsing, the same methods as those described as the first resist pattern forming method can be applied. It is. Thus, a second resist pattern different from the first resist pattern can be formed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

<Synthesis of Resin 1>
Under a nitrogen stream, 20 g of a 6/4 (mass ratio) mixed solvent of propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether was placed in a three-necked flask and heated to 80 ° C. (solvent 1). Butyrolactone methacrylate, hydroxyadamantane methacrylate and 2-methyl-2-adamantyl methacrylate are dissolved in a mixed solvent of 6/4 (mass ratio) of propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether at a molar ratio of 50/10/40. A 22 mass% monomer solution (200 g) was prepared. Furthermore, 8 mol% of initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the monomer, and the dissolved solution was added dropwise to (solvent 1) over 6 hours. After completion of dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then poured into 1800 ml of hexane / 200 ml of ethyl acetate. The precipitated powder was collected by filtration and dried to obtain 37 g of Resin (1). The obtained resin (1) had a weight average molecular weight of 8,800 and a dispersity (Mw / Mn) of 1.8.
Similarly, resins (2), (3), (4), (5), (6) and (PO-A) were synthesized.

  The structures of the resins (1) to (6) and (PO-A) are shown below, and the composition, mass average molecular weight and degree of dispersion are shown in Table 1.

[Preparation of resist]
The components shown in Table 2 below were dissolved in a solvent to prepare a solution having a solid content concentration of 5.8% by mass, and this was filtered through a polyethylene filter having a pore size of 0.1 μm to prepare a positive resist solution. In addition, about each component in Table 2, the ratio at the time of using multiple is a mass ratio.

[Preparation of freezing treatment]
The components shown in Table 3 below were dissolved in a solvent, and the obtained freezing treatment agent was filtered through a polyethylene filter having a pore size of 0.1 μm to prepare a freezing treatment agent.

The prepared treating agent solution and positive resist solution were used for evaluation by the following method.
Hereinafter, the abbreviations in each table are as follows.

[Basic compounds]
TPI: 2,4,5-triphenylimidazole PEA: N-phenyldiethanolamine DPA: 2,6-diisopropylphenyl alcohol PBI: 2-phenylbenzimidazole

[Surfactant]
W-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicon-based)

〔solvent〕
A1: Propylene glycol monomethyl ether acetate A2: γ-butyrolactone A3: Cyclohexanone B1: Propylene glycol monomethyl ether B2: Ethyl lactate C1: Tert-butanol C2: 2,3-dimethyl-2-pentanol C3: Perfluoro-2-butyl Tetrahydrofuran C4: Decane C5: Menthane

〔Processing agent〕

  As the compounds of (FG-01) to (FG-11), commercially available products (commercial products from Honshu Chemical Co., Ltd. and Tokyo Kasei Co., Ltd.) were used.

  〔Additive〕

  The prepared treating agent solution and positive resist solution were used for evaluation by the following method.

<Evaluation method>
<ArF dry exposure>
Hereinafter, a pattern forming method subjected to a freezing process will be described with reference to FIG. FIG. 1A:
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form an antireflection film 4 having a thickness of 78 nm. The first positive resist composition prepared thereon was applied, and baked at 115 ° C. for 60 seconds to form a first resist film 1 having a thickness of 160 nm.

(B) and (c) of FIG.
The wafer coated with the resist film 1 was subjected to pattern exposure using an ArF excimer laser scanner (PAS5500 / 1100, manufactured by ASML, NA0.75) through an exposure mask m1. The exposure amount was optimized to have a desired line width. After heating at 115 ° C. for 60 seconds, developing with an aqueous tetramethylammonium hydroxide solution (2.38% by mass) for 30 seconds, rinsing with pure water, spin drying, and a first 180 nm line width 90 nm first pitch. Resist patterns 1a and 1a ′ were obtained.

FIG. 1 (d), (e):
Subsequently, exposure with the ArF excimer laser scanner was performed at an exposure amount of 30 mJ / cm ² through a mask m2 so that the entire surface of the first resist pattern 1a ′ was exposed. After heating at 115 ° C. for 60 seconds, developing with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, spin drying, and resist film of resist pattern 1a ′ Was completely removed so that only the first resist pattern 1a remained on the wafer coated with the organic antireflection film.

(F) to (h) in FIG.
Subsequently, while rotating the wafer in which the first resist pattern 1a remains at 500 rpm, the processing agent 3 is discharged from the nozzle n at a flow rate of 2 cc / sec for 60 seconds, and then rotated at 2000 rpm for 60 seconds to remove the processing agent. Completely shaken out. Next, after baking at 130 ° C. for 90 seconds to advance the reaction, the wafer is cooled to room temperature, rinsed with 2-heptanol for 20 seconds, and a first pattern 1b subjected to a freezing treatment with a processing agent is formed. did.

(J) in FIG.
The prepared second positive resist composition is applied to the wafer having the processed first resist pattern 1b and baked at 115 ° C. for 60 seconds to form a second resist film 2 of 160 nm. did. Of the obtained wafer, a portion where the first resist pattern 1b did not exist was subjected to pattern exposure using the ArF excimer laser scanner through a mask m3 having a pitch of 180 nm and a line width of 90 nm.

FIG. 1 (k), (l):
Subsequently, a portion where the first resist pattern 1b and the second resist film 2 are mixed is 30 mJ / cm by means of the ArF excimer laser scanner through a mask m4 which shields the portion consisting only of the second resist film. The film was exposed to an exposure amount of ² , and then heated at 115 ° C. for 60 seconds, developed with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsed with pure water, and then spin-dried. In this way, the exposed portion of the resist film 2 exposed through the mask m3 and the portion of the second resist film 2 where the first resist pattern 1b exists are completely removed, and the second resist pattern is removed. 2a was formed and the first resist pattern 1c was exposed. In this way, a pattern in which the first resist pattern 1c and the second resist pattern 2a were arranged on the wafer with a pitch of 180 nm and a line width of 90 nm was formed.

<ArF immersion exposure>
Pure water is used as the immersion liquid, PAS5500 / 1250i manufactured by ASML equipped with a lens of NA 0.85 is used as the ArF excimer laser scanner, the pattern dimensions are changed to a pitch of 130 nm, the line width is 65 nm, and the film thickness is 120 nm. A pattern was formed using the same method as that shown in the above-mentioned “ArF dry exposure” except for the above.

  The results obtained by the above composition and method are shown in Tables 4 and 5.

The terms in Tables 4 and 5 will be described with reference to FIG.
The dimensional variation ratio before and after the treatment is the ratio of the dimensional variation of the width of the first resist pattern (1a) in (e) and the pattern (1b) after surface treatment in (h) in FIG. (1b / 1a × 100 (%)). Since it is preferable that the resist pattern does not vary before and after the surface treatment, the ratio is preferably closer to 100%.
The finished dimension ratio is the ratio of the finished dimensions of the first resist pattern (1c) and the second resist pattern (2a) (2a / 1c × 100 (%)). Since the first resist pattern and the second resist pattern are preferably equal in size, the ratio is preferably as close to 100%.
The pattern height ratio is the ratio of the pattern heights of the first resist pattern (1c) and the second resist pattern (2a) (2a / 1c × 100 (%)). Since the heights of the first resist pattern and the second resist pattern are preferably equal, the ratio is preferably as close to 100%.
The etching rate ratio means that the first resist pattern (1c) and the second resist pattern (2
The pattern etching rate of a) is expressed as a ratio (2a / 1c × 100 (%)). Since it is preferable that the etching rates of the first resist pattern and the second resist pattern are equal, the ratio is preferably closer to 100%.

  Table 4 shows the evaluation results by the dry exposure method, and Table 5 shows the evaluation results by the immersion exposure method. In Tables 4 and 5, * indicates that the pattern 1a has completely disappeared after treatment with the treating agent.

(Measurement of pattern dimensions)
The dimension of the resist pattern created by the above method was measured using a scanning electron microscope for length measurement (SEM, S-9380II manufactured by Hitachi, Ltd.).
(Measurement of pattern height)
The height of the resist pattern created by the above method was measured by SEM Hitachi Ltd. S-4800.

(Evaluation of dry etching resistance)
Each resist composition prepared in the same manner as described above was applied onto a silicon wafer subjected to hexamethyldisilazane treatment by spin coating, and baked at 115 ° C. for 60 seconds.
A resist film of 00 nm was formed. The resist film was etched using an ULVAC parallel plate type reactive ion etching apparatus under the conditions of an etching gas of oxygen, a pressure of 20 mTorr, and an applied power of 100 mW / cm ³ . The etching rate of the resist film was determined from the change in film thickness. The etching rate was calculated for the resist film with and without the freezing treatment using the treatment agent, and finally calculated as the etching rate ratio (after treatment / before treatment). .

From the results of Tables 4 and 5, the treatment agent for pattern formation of the present invention was compared with a comparative example in which the treatment agent was not used in the characteristic evaluation by ArF dry exposure and ArF immersion exposure.
(I) The first resist pattern does not dissolve in the second resist solution.
(Ii) As a result of greatly suppressing the dimensional variation of the first resist pattern,
The first resist pattern and the second resist pattern can be formed with the same dimensions.
(Iii) Dry etching of the first resist-coated film and the second resist-coated film
The tolerance is the same.

  Thus, the pattern forming treatment agent of the present invention acts on the resist pattern so as to satisfy all the characteristics required in the freezing process. Thus, it is clear that the processing agent for pattern formation of the present invention exhibits excellent pattern forming properties in the freezing process.

It is the schematic of the pattern formation method using a freezing process.

Explanation of symbols

1: Resist 1
1a: pattern formed using resist 1;
1b: Resist pattern 1a after treatment with a treating agent
1c: Resist pattern 1b after second exposure and development
2: Resist 2, 2a: Pattern formed using resist 2 3: Treatment agent 4: Semiconductor substrate (including antireflection film layer)
m: exposure mask m1 to m4 represent masks used in each process n: discharge nozzle

Claims (6)

A surface treatment agent used in a pre-process for forming a second resist film by forming a second resist film on the first resist pattern after forming the first resist pattern, on the benzene ring A structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms (X represents a monovalent organic group, a hydroxyl group, an amino group, or a mercapto group. R ₁ represents And a hydrogen atom or a monovalent organic group.) A surface treatment agent for forming a resist pattern, comprising a compound having at least one. A compound having at least one structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring is represented by the following general formula (1). The surface treatment agent for forming a resist pattern according to claim 1, wherein the compound is a compound.
General formula (1):

In the general formula (1), X represents a monovalent organic group, a hydroxyl group, an amino group, or a mercapto group.
When z = 1, A represents a hydrogen atom or a monovalent organic group.
When z is 2, A represents a single bond or a divalent organic group.
When z is 3 or more, A represents a z-valent organic group.
R ₁ represents a hydrogen atom or a monovalent organic group.
When z is 2 or more, a plurality of X, R ₁ and R ₂ may be the same or different.
R ₂ represents a monovalent organic group. However, A and R ₂ may be bonded to each other to form a ring.
When n is 2 or more, the plurality of R ₂ may be the same or different, and R ₂ may be bonded to each other to form a ring.
n represents an integer of 0 to 3. z represents an integer of 1 to 8. A compound having at least one structure having a group represented by X and a group represented by —CH ₂ —OR ₁ on adjacent carbon atoms on the benzene ring, or represented by the general formula (1) The surface treatment agent for forming a resist pattern according to claim 1 or 2, wherein the compound is a compound represented by the following general formula (2).
General formula (2):

In the general formula (2), X represents a monovalent organic group, a hydroxyl group, an amino group, or a mercapto group.
When z = 1, A represents a hydrogen atom or a monovalent organic group.
When z is 2, A represents a single bond or a divalent organic group.
When z is 3 or more, A represents a z-valent organic group.
R ₁ represents a hydrogen atom or a monovalent organic group.
When z is 2 or more, a plurality of X, R ₁ , R ₂ and R ₃ may be the same or different.
R ₂ represents a monovalent organic group. However, A and R ₂ may be bonded to each other to form a ring.
R ₃ represents a hydrogen atom or a monovalent organic group.
m represents an integer of 1 to 3. l represents an integer of 0-2. z represents an integer of 1 to 8.   In the compound represented by General formula (1) or General formula (2), z is 2 or more, The surface treatment agent for resist pattern formation of Claim 2 or 3 characterized by the above-mentioned.   Furthermore, the organic solvent is contained, The surface treating agent for resist pattern formation in any one of Claims 1-4 characterized by the above-mentioned.   A step of forming a first resist pattern using the first resist composition, a step of treating the resist pattern with the treating agent according to any one of claims 1 to 5, and on the first resist pattern Forming a second resist pattern using the second resist composition. A method of forming a resist pattern, comprising:

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