JP2010039036A - Surface treatment agent for pattern formation, and pattern forming method using the treatment agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treatment agent for a freezing process that meets the requirement that (1) the line width of a first resist pattern does not fluctuate and (2) the line edge roughness (LER) of the first resist pattern does not deteriorate, by a freezing process in a freezing process that is applied to the first resist pattern in a double patterning method, and a pattern forming method using it. <P>SOLUTION: The surface treatment agent for resist pattern formation contains a compound having an oxazoline group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface treatment agent for forming a resist pattern used in a manufacturing process of a semiconductor such as an IC, a manufacturing process of a circuit board such as a liquid crystal or a thermal head, and a lithography process of other photo application, and a pattern using the same. The present invention relates to a forming method.

  Particularly, the present invention relates to a surface treatment agent for forming a resist pattern suitable for exposure with an immersion type projection exposure apparatus using a deep ultraviolet light having a wavelength of 200 nm or less as a light source, and a pattern forming method using the same. is there.

  Since the exposure light source has been shortened to 248 nm using a KrF excimer laser, an image forming method called chemical amplification and a resist suitable for it have been used as a resist image forming method 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 the exposure light source has been shortened and the numerical aperture (high NA) of the projection lens has been increased. Currently, an exposure machine using an ArF excimer laser having a wavelength of 193 nm as a light source has been developed. The degree of achievement of miniaturization of a semiconductor element can be expressed by a resolving power, and can be expressed by the following equation as is generally 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 has been proposed in which the space between the projection lens and the sample is filled with a liquid having a high refractive index (hereinafter also referred to as “immersion liquid”).

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 (see, for example, Patent Documents 1 to 3 and Non-Patent Documents 1 to 4).

  As described in Non-Patent Document 3 and Non-Patent Document 4, the freezing process is a process in which a first resist pattern is formed on a first resist film and further formed on the first resist pattern. In the double patterning method for forming the second resist pattern on the second resist film, the first resist pattern is treated for the second time by performing chemical or physical treatment on the first resist pattern. It is a process including a step of substantially insolubilizing a resist solvent to be applied and a developing solution. By using the freezing process, it is possible to perform etching after continuing the lithography process from exposure to development twice, and it is possible to reduce the etching process after the first exposure. Here, “substantially insolubilized” with respect to the solvent and developer of the resist to be applied the second time means that the resist that has been applied the second time is insolubilized in the solvent. When the second resist solution is applied onto the resist pattern, the first resist film thickness decreased within the application time (typically within 60 seconds) is within 5% of the initial film thickness. Indicates that

  In Patent Document 1, a treating agent for freezing containing a specific metal compound is allowed to act on a first resist pattern to form a metal oxide film, which is insolubilized in a resist solvent and a developing solution to be applied a second time. A method has been proposed.

  However, in this method, since the metal oxide film is not formed on the second resist pattern, a difference in etching resistance occurs between the first resist pattern and the second resist pattern. It is difficult to control. In order to avoid this, it is conceivable to apply a surface treatment agent to the second resist pattern, but there is a problem that the number of steps increases.

In Non-Patent Document 1, Non-Patent Document 2, and Patent Document 3, a processing agent for freezing containing a specific resin and a crosslinking agent is allowed to act on the first resist pattern to form a film made of a resin composition of the processing agent. In addition, a method of insolubilizing with respect to the resist solvent and developer to be applied the second time has been proposed.
Further, Patent Document 2 proposes a method of modifying a first resist pattern by irradiating the first resist pattern with vacuum ultraviolet rays so as to insolubilize the resist resist and a developing solution to be applied a second time. Yes.

  Patent Document 3 discloses a treating agent for freezing using an aqueous solution containing a water-soluble resin and a water-soluble crosslinking agent as essential components.

However, for example, the method disclosed in Patent Document 3 has a problem that the resist pattern becomes thick and the resolution is lowered.
JP 2008-33174 A JP 2006-18095 A JP 2008-083537 A Proceedings of SPIE, 6153, 615301 (2006) Proceedings of SPIE, 6923, 69230H (2008) Proceedings of SPIE, Vol. 6924, 69240R (2008) Proceedings of SPIE, 6520, 65200F (2007)

  The present invention has been made in view of the above circumstances. In the freezing process performed on the first resist pattern in the double patterning method, (1) the line width of the first resist pattern is not changed by the freezing process. (2) A surface treatment agent for a freezing process that satisfies the requirement that the line edge roughness (LER) of a first resist pattern does not deteriorate, and a pattern forming method using the same.

As a result of intensive studies to solve the above problems, the present inventor has reached the present invention shown below.
(1) A surface treatment agent for forming a resist pattern, comprising a compound having an oxazoline group.
(2) The surface treatment agent for forming a resist pattern according to (1), wherein the compound having an oxazoline group is an oxazoline group-containing polymer.
(3) The surface treatment agent for forming a resist pattern according to (1) or (2), further comprising a compound having an oxazoline group and a polymer inert to the resist pattern.
(4) The surface treatment agent for forming a resist pattern according to any one of (1) to (3), further comprising a surfactant.

  (5) In a resist pattern having a first resist pattern formed from the first resist film and a second resist pattern formed from the second resist film formed on the first resist pattern, The surface treatment agent for forming a resist pattern according to any one of (1) to (4), wherein the surface treatment agent is for forming a resist pattern.

(6) forming a first resist pattern on the first resist film, forming a first resist pattern, forming a second resist film on the first resist pattern obtained in the step, In a resist pattern forming method including a second resist pattern forming step of forming a second resist pattern on the second resist film, between the first resist pattern forming step and the second resist pattern forming step, ( A process for forming a resist pattern, comprising a step of processing the first resist pattern using the surface treating agent according to any one of 1) to (5).
(7) Further heating between the step of surface-treating the first resist pattern using the surface treating agent according to any one of (1) to (5) and the second resist pattern forming step The method for forming a resist pattern according to (6), further comprising a step.

  According to the present invention, in the double patterning method, a freezing process that satisfies the requirements that the line width of the first resist pattern does not change and the line edge roughness does not deteriorate due to the freezing treatment and the formation of the second resist pattern is provided. Became possible.

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).

  In the present invention, the first resist pattern is formed by exposing the first resist film (1) through the pattern mask (m1), for example, as shown in FIG. The second resist pattern is formed when the second resist film (2) is exposed to the second pattern through the pattern mask (m2). This represents the resist pattern (2a).

1. Surface treatment agent for resist pattern formation <Compound having oxazoline group>
The resist pattern forming surface treatment agent of the present invention contains a compound having an oxazoline group (hereinafter, also referred to as “chemical species of the present invention”) as an essential component.
The chemical species of the present invention is not limited as long as the oxazoline group can form an amide ester bond with a carboxyl group present on and / or in the resist pattern. The group of the structure represented by 1) is pointed out.

In the formula, R ₁ , R ₂ , R ₃ , and R ₄ each independently represent hydrogen, a halogen element, an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group.
* Represents a bond with another atomic group.

The _{R 1, R 2, R 3} , R 4, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, preferably a cycloalkyl group having 3 to 8 carbon atoms, more preferably a hydrogen atom.
The alkyl group, cycloalkyl group, aralkyl group, and aryl group of R _{1 to} R ₄ may have a substituent, and examples of the substituent include a hydroxyl group, a cyano group, a halogen atom, an alkyl group, and a cycloalkyl group. , An aralkyl group, an aryl group, and the like.

  The compound having an oxazoline group is preferably a polymer containing an oxazoline group, more preferably an oxazoline group-containing polymer having at least two oxazoline groups, and particularly preferably at least three or more oxazoline groups. It has an oxazoline-containing polymer. By using such a polyfunctional oxazoline-containing polymer, the same or different resins can be cross-linked with the polyfunctional oxazoline, reducing the dissolution of the first resist pattern in the resist solvent applied the second time. can do. However, as long as it can form an amide ester bond with the carboxyl group contained in the resist pattern as described above, the chemical species of the present invention is not limited to the polymer, and includes compounds other than the polymer.

The addition amount of the compound having an oxazoline group is preferably 0.01 to 99% by mass, more preferably 0.1 to 80% by mass, and still more preferably 1 to 60% by mass with respect to the total amount of the surface treatment agent. .
A compound having an oxazoline group may be used alone or in combination of two or more.

The oxazoline group-containing polymer in the present invention is obtained, for example, by polymerizing an addition polymerizable oxazoline compound represented by the following general formula (2). Further, it is obtained by polymerizing an addition polymerizable oxazoline compound represented by the general formula (2) and another copolymerizable monomer.

In formula, R < ₁ >, R < ₂ >, R < ₃ >, R < ₄ > is synonymous with General formula (1). R ₅ is an acyclic organic group having an addition polymerizable unsaturated bond. Examples of R ₅ include a group having a vinyl structure, a group having an isopropenyl structure, and a group having a (meth) acryloyl structure.

  Specific examples of the addition polymerizable oxazoline compound represented by the general formula (2) include, for example, 2-vinyl-2oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxozaline, Examples include 2-isopropenyl-4-methyl-2-oxozaline, 2-isopropenyl-5-ethyl-2-oxozaline, and the like. These may use only 1 type and may mix and use 2 or more types.

  The other copolymerizable monomer copolymerized with the addition-polymerizable oxazoline group-containing compound is not particularly limited as long as it is a monomer that does not react with the oxazoline group and can be copolymerized with the addition-polymerizable oxazoline compound. For example, (meth) acrylic acid esters such as methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, unsaturated nitriles such as (meth) acrylonitrile, (meth ) Unsaturated amides such as acrylamide and N-methylol (meth) acrylamide, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, α-olefins such as ethylene and propylene, halogen-containing compounds such as vinyl chloride, vinylidene chloride and vinyl fluoride α, β-unsaturated monomers, styrene, α-methylstyrene, sodium styrenesulfonate Such um alpha, beta-unsaturated aromatic monomer include, and the like. These can use 1 type (s) or 2 or more types.

  As the oxazoline group-containing polymer, a water-soluble polymer and an aqueous emulsion can also be used. As the water-soluble polymer, known polymers such as an acrylic polymer containing an oxazoline group in the side chain and an acrylic polymer such as a polystyrene-acrylonitrile copolymer containing an oxazoline group in the side chain can be used. A commercially available product can be used. Specific examples of water-soluble polymers include “Epocross WS-500” and “Epocross WS-700” manufactured by Nippon Shokubai Co., Ltd. 1000 ”series and“ Epocross K-2000 ”series.

<Inert polymer>
The compound having an oxazoline group and a polymer inert to the resist pattern The surface treatment agent of the present invention preferably contains a compound having an oxazoline group and a polymer inert to the resist pattern. In the present invention, the “inert polymer” means that a chemical bond is formed with a compound having an oxazoline group and a functional group contained in the resist pattern within the range of the freezing process conditions (temperature, pressure, etc.) described in the present specification. It refers to a polymer that does not react substantially.

  As the inert polymer, an alcohol or water-soluble dispersant polymer that does not dissolve the resist pattern is preferable. Examples thereof include polyalkylene oxide, polyalkylene glycol, polyvinyl ether, polystyrene, poly (methyl) methacrylate, and polyvinyl ester. , Polyamide, polysiloxane and the like. Among these, polyalkylene oxide and polyalkylene glycol are preferable. In addition, in order that polyalkylene oxide and polyalkylene glycol may suppress reaction with the chemical species of this invention, it is thought that it is preferable that the terminal is sealed with the ether structure or the ester structure.

Specific examples of the inert polymer that can be used in the present invention include the following.
Examples of the polyalkylene oxide include polyethylene oxide dialkyl ether, polyethylene oxide diester, polypropylene oxide dialkyl ether, and polypropylene oxide diester.
Examples of the polyalkylene glycol include polyethylene glycol dialkyl ether, polyethylene glycol diester, polypropylene glycol dialkyl ether, and polypropylene glycol diester.

Examples of polystyrene include polystyrene, polyalkyl styrene, polyalkoxy styrene, polyvinyl benzoate, polyvinyl benzoic acid amide, polyhydroxy styrene salt, polyvinyl benzoate, and polystyrene sulfone salt.
Examples of poly (methyl) methacrylate include polyacrylate, polymethacrylate, and polymethacrylate, polyacrylate, polymethacrylamide, and polyacrylate.

Examples of the polyvinyl ether include polymethyl vinyl ether, polyisobutyl vinyl ether, and poly [2- (methoxyethoxy) ethylene].
Polyvinyl acetate is mentioned as a polyvinyl ester.
Examples of the polyamide include polyalanine, polyphenylalanine, polyglycine, polyleucine, polyisoleucine, polyvaline, polymethionine, and copolymers thereof.
Examples of polysiloxane include polydimethylsiloxane.

The weight average molecular weight of the inert polymer is preferably 5000 to 200,000, more preferably 7500 to 100,000, as measured by GPC of polyethylene oxide standard.
When the treatment agent of the present invention contains an inert polymer, the content is usually 1 to 10, preferably 1 to 6, more preferably 1.5 to 4 in terms of mass ratio with respect to the chemical species of the present invention. It contains in the ratio of.

<Solvent>
The surface treatment agent for forming a resist pattern of the present invention may contain a solvent. Any solvent can be used as long as it does not dissolve the first resist pattern and dissolves the chemical species of the present invention. Here, not dissolving the first resist pattern means that when a line and space pattern having a pattern height of 0.2 μm and 200 nm is formed under a condition of 23 ° C. and immersed in an organic solvent for 10 minutes, the pattern It is shown that both the width variation and the pattern height variation are within ± 5%. Examples of such a solvent include water, alcohol solvents, fluorine solvents, saturated hydrocarbon solvents, and the like. Among these, water is preferable from the viewpoint of solubility of the chemical species of the present invention.

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 methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, isobutanol, tert-pentanol, n-hexanol, n-heptanol, 2- Heptanol, n-octanol, n-decanol, 3-methyl-3-pentanol, 2,3-dimethyl-2-pentanol, 4-phenyl-2-methyl-2-hexanol, 1-phenyl-2-methyl- Examples include 2-propanol, s-amyl alcohol, t-amyl alcohol, isoamyl alcohol, 2-ethyl-1-butanol, and n-undecanol. Among these, alcohols having 4 to 11 carbon atoms are preferable. More preferably, it has 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 volatilization of the solvent.

  As the solvent, a mixed solvent of water and an alcohol solvent can also be used. The mixing ratio of water and alcohol solvent is preferably 10/90 to 95/5, more preferably 20/80 to 80/20, and still more preferably 30/70 to 70/30.

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 the content rate 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.

Examples of the saturated hydrocarbon solvent include linear or branched alkanes and cycloalkanes. Specifically, pentane, 2-methylbutane, 3-methylpentane, hexane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, octane, 2,2,4-trimethylpentane, 2,2,3 -Trimethylhexane, nonane, decane, undecane, dodecane, 2,2,4,6,6-pentamethylheptane, tridecane, pentadecane, tetradecane, hexadecane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, etc. can be used. . These organic solvents can be used alone or in combination. Terpene-based saturated hydrocarbons can also be used as the solvent, and specifically, cyclic saturated terpenes such as pinane, bornane, caran, fencan, tsujang, o-menthane, m-menthane, and p-menthane are preferable. These saturated hydrocarbon solvents that can be cited preferably have 6 to 10 carbon atoms, 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.

  As the solvent that can be used for the surface treatment agent, any solvent may be used as long as it does not dissolve the first resist pattern and dissolves the chemical species of the present invention. In particular, a polar solvent having a relative dielectric constant of 10 or more. Is preferred. Moreover, it is preferable to use 80 mass% or more of water, an alcohol solvent, a fluorine solvent, a saturated hydrocarbon solvent, or a mixture thereof in the solvent to be used, and more preferably 100 mass%. Particularly in the present invention, a solvent containing 80% by mass or more of water is preferable.

  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 content of the solvent in the treating agent is such that the total solid concentration including the chemical species of the present invention is preferably 98 to 0.001% by mass, more preferably 50 to 0.01% by mass, and still more preferably 30 to 0%. It can be adjusted to be 0.05 mass%.

<Surfactant>
The treatment agent of the present invention preferably contains a surfactant.
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. Surfactants include nonionic, anionic, cationic and amphoteric surfactants.

  Nonionic surfactants include Plufarac LE400, Plufarac LE221, Plufarac LP101, Plufarac P104, Plufarac P105, Plufarac P123, Pluronic PE10300, Pluronic PE6200, Pluronic RPE2520 and Tetronic RED9040 (above BASF), ELEBASE BA-100, ELEBASE -200, ELEBASE BCP-2, BUB-3, ELEBASE BUB-4, ELEBASE CP-800K, ELEBASE EDP-475, ELEBASE HEB-5, Finesurf 270, Finesurf 7045, Finesurf 7085, Braunon DSP-12.5, Braunon DT-03, BROWNON L-205, BROWNON LPE-1007, BROWNON MXDA E0-4, BROWNON O-205, BROWNON S-202, BROWNON S-204, BROWNON S-207, BROWNON S-205T ), Adeka Pluronic P-103 (manufactured by Asahi Denka Kogyo Co., Ltd.), Emulgen A-500, Emulgen PP-290, Emulgen 104P, Emulgen 108, Emulgen 404, Emulgen 408, Emulgen A-60, Emal B-66, Emulgen LS-106, Emulgen LS-114, Amit 102, Amate 105, Amit 302, Amit 320, Aminone PK-02S, Emanon CH-25, Rheodor 430V, Rheodor 440V, Rheodor 460V, Rheodor TW-S106 , Rheodor TW-S120V, Rheodor Super TW-L120 (above Kao Chemical), Surflon S-141 (above AGC Seimi Chemical), Neugen EA-177, Neugen EA-137 (Daiichi Kogyo Seiyaku) New Calgen 3000S, New Calgen 500, New Calgen FS-3PG, New Calgen FS-7PG, Pionin D-6414 (manufactured by Takemoto Yushi Co., Ltd.), DYNOL604, Environment Gem AD01, Olphin EXP. 4001, Olphin EXP. 4036, Olfine EXP. 4051, Olfin PD-002W, Surfinol 2502, Surfinol 440, Surfinol 465, Surfinol 485, Surfinol 61 (manufactured by Nissin Chemical Industry Co., Ltd.), Footent 300 (manufactured by Hishoe Chemical Co., Ltd.), Poem C-250 Poem J-0021, Poem 0081HV, Riquemar L-250A, Riquemar O-852 (manufactured by Riken Vitamin Co., Ltd.) and the like can be used.

  As anionic surfactant, EMAL 20T, Poise 532A (above Kao Chemical Co., Ltd.), Phosphanol ML-200 (TOHO Co., Ltd.), EMULSOGEN COL-020, EMULSOGEN COA-070, EMULSOGEN COL-080 (above Clariant Japan) ), Surflon S-111N, Surflon S-211 (AGC Seimi Chemical Co., Ltd.), Plysurf A208B, Plysurf A210B, Plysurf A210G, Plysurf A212C, Plysurf A219B, Plysurf AL, Labelin FC-45 (Above made by Daiichi Kogyo Seiyaku Co., Ltd.), Pionein A-29-M, Pionein A-44TW (above made by Takemoto Yushi Co., Ltd.), Orphine PD-201, Orphine PD-202 (above made by Nissin Chemical Industry Co., Ltd.), AKYPO RLM45 , ECT-3 (manufactured by Nippon Surfactant Co., Ltd.) Lipon LH-200 (manufactured by Lion Corporation), POEM K-30, POEM K-37V (or Riken Vitamin Co., Ltd.) can be used.

As a cationic surfactant, acetamine 24, acetamine 86 (manufactured by Kao Chemical Co., Ltd.) or the like can be used.
As an amphoteric surfactant, Surflon S-131 (manufactured by AGC Seimi Chemical Co., Ltd.), Enagicol C-40H, Lipomin LA (manufactured by Kao Chemical Co., Ltd.) or the like can be used.
These surfactants can also be mixed and used.

<Other additives>
Furthermore, the treatment agent of the present invention may contain an acid, a compound that generates an acid by heating, and / or a base as necessary in order to promote the reaction with the first resist pattern.
As the acid that can be added, a low molecular acid such as carboxylic acid or sulfonic acid can be used. Preferably, a low carboxylic acid partially fluorinated or a low sulfonic acid partially fluorinated such as sulfonic acid. Molecular acids are mentioned. 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. Examples of counter anions of these onium salt type compounds include SbF ₆ ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , toluenesulfonate, and triflate. Furthermore, examples of the compound that generates an acid by heating include esters of alkyl or aryl sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, and toluenesulfonic acid.
The temperature for generating the acid is usually 200 ° C. or lower, preferably 160 ° C. or lower.

Preferred examples of the base include basic compounds having a structure 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, an aralkyl group, an acyloxy group, and an aryloxy group. Etc. 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 alkyl sulfonate, the alkyl group has 1 to 20 carbon atoms, in the case of cycloalkyl sulfonate ester, the cycloalkyl group has 3 to 20 carbon atoms, and in the case of 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 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. The addition amount of the base is generally 0.001 to 10% by mass, preferably 0.01 to 5% by mass with respect to the total amount of the treatment agent.

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

  In the present invention, various crosslinking agents known in the art (for example, epoxy crosslinking agents, oxetane crosslinking agents, crosslinking agents having an N-methylol group (urea crosslinking agents, melamine crosslinking agents) Etc.) can also be used within the scope of the effects of the present invention, but it is preferable that these crosslinking agents are not substantially contained in the present invention.

2. First resist In the present invention, after forming the first resist pattern on the first resist film, the first resist pattern is dissolved in the second resist solution by the treatment agent containing the chemical species of the present invention. It is important to change so that it does not. This control 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 preferably contains (A) a resin that is decomposed by the action of an acid and increases the solubility in an alkaline developer, and (B) a compound that generates an acid upon irradiation with actinic rays or radiation.

[1] Resin (resin (A)) that is decomposed by the action of an acid to increase the solubility in an alkaline developer
As the resin (A), the first resist is used in order to cause esterification reaction with the treating agent containing the chemical species of the present invention and to change the properties so that the first resist pattern is not dissolved in the second resist solution. It is preferable that a carboxyl group is generated by a chemical reaction during the process of forming a 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”).

  Alkali-soluble groups include phenolic hydroxyl groups, carboxyl groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) (alkylcarbonyl) imides. Group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) methylene group, etc. Is 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 in which the hydrogen atom of these alkali-soluble groups is substituted 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.

  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, a plurality of substituents (Rb ₂ ) may be the same or different, and a plurality of 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 (AII).

In general formula (AII),
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 dependence become good.

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 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 formulas (VIIa) to (VIId) include the repeating units represented by the following general formulas (AIIa) to (AIId).

In the 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 preferably 5 to 40 mol%, more preferably 5 to 30 mol%, based on all repeating units in the resin (A). Preferably it is 10-25 mol%.

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, and tetracyclic hydrocarbon rings such as perhydro-1,4-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 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) Dry etching resistance,
Etc. can be finely adjusted.

  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, generation | occurrence | production of the particle at the time of a preservation | save 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 initiators 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). Alternatively, a method including precipitating a resin solid (step d) and separating the precipitated resin (step e) may be used.

  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. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, and deterioration of developability and film formation due to increase in viscosity can be prevented. it can.

  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.

[2] Compound that generates acid upon irradiation with actinic rays or radiation (component (B))
The positive photosensitive composition of the present invention contains a compound that generates an acid upon irradiation with actinic rays or radiation (hereinafter also referred to as “acid generator”).

  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 1-30, 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 the corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.
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 a part of R _{201 to} R ₂₀₃ may be an aryl group with the remaining being 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 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 linear or branched may be any of, for example, alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 linear or branched alkyl group having a carbon number ( 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 photosensitive 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 photosensitive composition. More 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, an aralkyl group, an acyloxy group, and an aryloxy group. Etc. 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 alkyl sulfonate, the alkyl group has 1 to 20 carbon atoms, in the case of cycloalkyl sulfonate ester, the cycloalkyl group has 3 to 20 carbon atoms, and in the case of 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 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, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.

  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 (Dainippon Ink Chemical Co., Ltd.), 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 Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF802, EF 01 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204G, 208G, 218G, 230G, 204D, 208D, 212D, 218D, 222D (manufactured by Neos) Fluorine type surfactant or silicon type surfactant can be mentioned. 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 when preparing the positive resist composition by dissolving the above 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.
3. 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 From the viewpoint of making the dry etching resistance 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.

<Formation of first resist pattern>
In the present invention, the first resist composition is filtered and then applied onto 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]
Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the resist film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a refractive index higher than that of air, but pure water is preferred.

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 a refractive index temperature coefficient as small as possible so as to minimize distortion of the optical image projected onto the resist film. Is an ArF excimer laser (wavelength; 193 nm), it is preferable to use water from the viewpoints of availability and ease of handling in addition to the above-mentioned viewpoints.

  Further, a medium having a refractive index of 1.5 or more can be used in that the refractive index can be further improved. This medium may be an aqueous solution or an organic solvent.

  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 film 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 methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. By adding an alcohol having a refractive index substantially equal to that of water, even if the alcohol component in water evaporates and the content concentration changes, an advantage that the change in the refractive index of the entire liquid can be made extremely small can be 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 filter or the like may be used.

  The electrical resistance of 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.

  When the resist film made of the positive resist composition of the present invention is exposed through an immersion medium, a hydrophobic resin (HR) can be further added as necessary. As a result, hydrophobic resin (HR) is unevenly distributed on the surface of the resist film, and when the immersion medium is water, the receding contact angle of the resist film surface with respect to the water when the resist film is formed is improved, and the immersion water tracking is improved. Can be made. As the hydrophobic resin (HR), any resin can be used as long as the receding contact angle of the surface can be improved by addition, but a resin having at least one of fluorine atom and silicon atom is preferable. The receding contact angle of the resist film is preferably 60 ° to 90 °, more preferably 70 ° or more. The addition amount can be adjusted and used 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 based on the total solid content of the positive resist composition, More preferably, it is 0.1-5 mass%. Hydrophobic resin (HR) is ubiquitous at the interface as described above, but unlike a surfactant, it does not necessarily have a hydrophilic group in the molecule, and polar / nonpolar substances are mixed uniformly. There is no need to contribute.

  The receding contact angle is the contact angle measured when the contact line at the droplet-substrate interface recedes, and is useful for simulating the ease of droplet movement under dynamic conditions. It is generally known. In simple terms, it can be defined as the contact angle when the droplet interface recedes when the droplet discharged from the needle tip is deposited on the substrate and then sucked into the needle again. It can be measured by using a contact angle measuring method generally called an expansion / contraction method.

  In the immersion exposure process, the immersion head needs to move on the wafer following the movement of the exposure head to scan the wafer at high speed to form the exposure pattern. In this case, the contact angle of the immersion liquid with respect to the resist film is important, and the resist is required to follow the high-speed scanning of the exposure head without remaining droplets.

The fluorine atom or silicon atom in the hydrophobic resin (HR) may be contained in the main chain of the resin or may be substituted on the side chain.
The hydrophobic resin (HR) 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.

  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 the aryl group 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.

Hereinafter, although the specific example of the repeating unit which has a fluorine atom is shown, this invention is not limited to this.
In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .

X ₂ represents —F or —CF ₃ .

  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.

Hereinafter, although the specific example of the repeating unit which has group represented by general formula (CS-1)-(CS-3) is given, this invention is not limited to this. In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .

  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 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. Examples include repeating units in which an alkali-soluble group is bonded to the chain. Furthermore, a polymerization initiator or a chain transfer agent having an alkali-soluble group can be used at the time of polymerization to be introduced at the end of the polymer chain. Is also preferable.

  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 polymer.

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

  (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 group, an acid imide group, and the like, and preferably a lactone A group having a structure.

  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%, still more preferably based on all repeating units in the polymer. 5 to 15 mol%.

  Specific examples of the repeating unit having a group (y) that increases the solubility in an alkali developer include the same repeating units as those having a lactone structure exemplified for the resin of the component (B).

  In the hydrophobic resin (HR), examples of the repeating unit having a group (z) that is decomposed by the action of an acid are the same as the repeating unit having an acid-decomposable group exemplified in the resin of the component (B). . In the hydrophobic resin (HR), the content of the repeating unit having a group (z) that is decomposed by the action of an acid is preferably 1 to 80 mol%, more preferably 10 to 10%, based on all repeating units in the polymer. 80 mol%, more preferably 20 to 60 mol%.

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

In general formula (III):
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 general formula (III), the alkyl group represented by 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 for the hydrophobic resin (HR), it is preferable that the residual monomer and oligomer components are 0 to 10% by mass, more preferably, as in the resin of the component (B), there are few impurities such as metals. Is more preferably 0 to 5% by mass and 0 to 1% by mass. 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.

  As the hydrophobic resin (HR), various commercially available products can be used, or they 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, generation | occurrence | production of the particle at the time of a preservation | save 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. The concentration of the reaction is 5 to 50% by mass, preferably 30 to 50% 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 completion of the radical polymerization reaction, a solvent in which the polymer is hardly soluble or insoluble is brought into contact, the resin is precipitated (step a), the resin is separated from the solution (step b), and dissolved again in the solvent. (Step c), and then contact 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 5 times or less volume). This may be a method including precipitating a resin solid (step d) and separating the precipitated resin (step e).

Specific examples of the hydrophobic resin (HR) are shown below. Table 1 below shows the molar ratio of the repeating units in each resin (corresponding to each repeating unit in order from the left), the weight average molecular weight, and the degree of dispersion.

  Since the resist film is not directly brought into contact with the immersion liquid between the resist film of the positive resist composition of the present invention and the immersion liquid, it is also referred to as an “immersion liquid hardly soluble film” (hereinafter referred to as “top coat”). ) May be provided. The necessary functions for the top coat are suitability for application to the upper layer of the resist, radiation, especially transparency to 193 nm, and poor immersion liquid solubility. It is preferable that the top coat is not mixed with the resist and can be uniformly applied to the resist upper layer.

  From the viewpoint of 193 nm transparency, the top coat is preferably a polymer that does not contain abundant aromatics. Specifically, the polymer contains a hydrocarbon polymer, an acrylate polymer, polymethacrylic acid, polyacrylic acid, polyvinyl ether, and silicon. Examples thereof include a polymer and a fluorine-containing polymer. The aforementioned hydrophobic resin (HR) is also suitable as a top coat. From the viewpoint of contaminating the optical lens when impurities are eluted from the top coat into the immersion liquid, it is preferable that the residual monomer component of the polymer contained in the top coat is small.

  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 film 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 film 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 film.

  The resolution is improved when there is no difference in refractive index between the top coat and the immersion liquid. In the case of using water as the immersion liquid in an ArF excimer laser (wavelength: 193 nm), the top coat for ArF immersion exposure is preferably close to the refractive index of the immersion liquid. From the viewpoint of making the refractive index close to the immersion liquid, it is preferable to have fluorine atoms in the topcoat. A thin film is more preferable from the viewpoint of transparency and refractive index.

  The top coat is preferably not mixed with the resist film and further not mixed with the immersion liquid. From this point of view, when the immersion liquid is water, the solvent used for the top coat is preferably a water-insoluble medium that is hardly soluble in the solvent used for the positive resist composition. Furthermore, when the immersion liquid is an organic solvent, the topcoat may be water-soluble or water-insoluble.

  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 0.1 to 10 mol%, preferably 0.5 to 5 mol%, and more preferably 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.

  Also, spin coating is preferred as a method for applying the treating agent on the resist pattern. In the case of spin coating, the processing agent is discharged to the center of the substrate for 0.5 to 5 seconds at a flow rate of 0.5 to 5 ml / second while rotating the substrate at 50 to 500 rpm, and then the substrate is driven at 10 to 500 to 3000 rpm. It is preferable to rotate for 60 seconds to shake off excess treatment agent and apply the treatment agent.

In the present invention, it is preferable to heat the substrate after the dipping / coating or in parallel with the dipping / coating in order to advance the reaction between the treating agent of the present invention and the resist pattern.
Usually, the heating temperature is preferably 60 ° C. or higher and 200 ° C. or lower, more preferably 80 ° C. or higher and 180 ° C. or lower, and 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. When the treatment agent of the present invention contains a polymer or oligomer, a film of the treatment agent is formed on the substrate by the above process.

  After reacting the treating agent with the resist pattern, it is preferable to wash the substrate with a solvent in order to remove excess treating agent from the substrate. As the solvent in this case, it is preferable to use pure water or the solvent used in the treatment agent. The cleaning method is as follows. First, a paddle is formed on the substrate with a solvent and allowed to stand, and then the solvent is rotated at 50 to 500 rpm while the solvent is rotated at a flow rate of 0.5 to 5 ml / second at the center of the substrate. A method is preferred in which the excess processing solvent is shaken off while discharging the substrate for 2 seconds and rotating the substrate at 500 to 3000 rpm for 10 to 60 seconds, but is not limited thereto.

  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. Further, instead of heating, the solvent may be removed by blowing the substrate with an inert gas such as nitrogen gas.

<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 in 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. In this manner, 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 (4)>
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, and the precipitated powder was collected by filtration and dried to obtain 37 g of Resin (B1).

As a result of GPC measurement using polystyrene as a standard, the obtained resin (4) had a weight average molecular weight (Mw) of 8800 and a dispersity (Mw / Mn) of 1.8.
Similarly, resins (1), (2), (3), (5), and (1b), (2b), (3b) were synthesized.

The structures of the resins (1) to (5) and (1b) to (3b) are shown below, and the composition of repeating units (corresponding to each repeating unit in order from the left), the weight average molecular weight and the degree of dispersion are shown in Table 2. .

[Preparation of resist]
The components shown in Table 3 below were dissolved in a solvent, and a solution with a solid content of 3.5% by mass was prepared for each, and this was filtered through a 0.1 μm polyethylene filter to form positive resist compositions Ar-01 to Ar. -05 was prepared.

  The (b) acid generator, (c) basic compound, (d) surfactant, and solvent shown in Table 3 are as follows.

[(B) Acid generator]

[(C) Basic compound]
TPI: 2,4,5-triphenylimidazole PEA: N-phenyldiethanolamine DPA: 2,6-diisopropylphenyl alcohol PBI: 2-phenylbenzimidazole [(d) 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

[Preparation of surface treatment agent]
The components shown in Table 4 below were dissolved in a solvent, and each of the resulting solutions was filtered through a polyethylene filter having a pore size of 0.1 μm to prepare surface treatment agents F-01 to 06 having a solid content concentration of 5%.

  The oxazoline group-containing compounds, dispersants, additives, surfactants, and solvents shown in Table 4 are as follows.

[Compound having oxazoline group]
FG-01: Epocros WS-500 (manufactured by Nippon Shokubai Co., Ltd.)
FG-02: Epocros WS-700 (manufactured by Nippon Shokubai Co., Ltd.)
[Inert polymer]
PEO: Polyethylene oxide (weight average molecular weight: 10,000)
PVA: polyvinyl alcohol (weight average molecular weight: 10,000)
〔Additive〕
(CHTs)

[Surfactant]
W-4: Surfinol 440 (manufactured by Nissin Chemical Industry Co., Ltd.)
W-5: Surfinol 465 (manufactured by Nissin Chemical Industry Co., Ltd.)
〔solvent〕
C3: Water.

<Pattern forming method for freezing process>
Using the prepared surface treatment agent and positive resist composition, a pattern was formed by the following method and evaluated.

[Formation of pattern]
Hereinafter, a pattern forming method subjected to a freezing process will be described with reference to FIG.
An organic antireflection film (ARC29A (manufactured by Nissan Chemical Industries)) was applied on the silicon wafer 5 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 uniformly applied by spin coating, and baked at 110 ° C. for 60 seconds to form a first resist film 1 having a thickness of 80 nm (FIG. 1A )).

  Next, the wafer coated with the resist film 1 was subjected to immersion pattern exposure using an ArF excimer laser scanner (TWINSCAN XT: 1700Fi manufactured by ASML) through an exposure mask m1 (line / space = 1/1) (FIG. 1 (b)). Pure water was used as the immersion liquid. The exposure amount was optimized so as to obtain a desired line width. Thereafter, the mixture was heated at 120 ° C. for 60 seconds, developed with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsed with pure water, and spin-dried. Further, the remaining water was removed by heating at 90 ° C. for 90 seconds to obtain a first resist pattern 1a having a pitch of 100 nm and a line width of 50 nm (FIG. 1C).

  Subsequently, a surface treatment agent (freezing agent) is spin-coated on the substrate to a desired film thickness by adjusting the number of rotations (FIG. 1 (d)), and baked at 100 ° C. for 90 seconds, with a film thickness of 150 nm. The reaction was allowed to proceed while forming the surface treating agent film 10 (FIG. 1 (e)). Thereafter, in order to remove excess processing agent, pure water is discharged from the nozzle n at a flow rate of 2 cc / sec for 5 seconds to form a paddle at the center of the substrate, and the substrate is left to stand for 30 seconds to surface-treat the pure water. The solvent used for the treatment agent (consisting only of the solvent and not containing other components) was discharged at the flow rate of 1 ml / second for 10 seconds at the center of the substrate while contacting the agent film and rotating the substrate at 300 rpm. Thereafter, the substrate was rotated at 2000 rpm for 30 seconds to shake off the solvent. In order to remove the solvent remaining on the substrate, it was heated at 90 ° C. for 90 seconds and cooled to room temperature (FIG. 1 (f)).

  Next, a second positive resist composition is applied on the substrate on which the first resist pattern 1b subjected to the above chemical treatment is formed, and baked at 110 ° C. for 60 seconds to obtain a film having a thickness of 80 nm. A second resist film 2 was formed (FIG. 1 (g)). At this time, the same 2nd resist composition as the 1st resist composition was used.

The wafer coated with the resist film 2 was subjected to immersion pattern exposure using an ArF excimer laser scanner (TWINSCAN XT: 1700Fi, manufactured by ASML) through an exposure mask m2 (line / space = 1/1) (FIG. 1 ( h)). Pure water was used as the immersion liquid, and the exposure amount was optimized to have a desired line width. Thereafter, the mixture was heated at 120 ° C. for 60 seconds, developed with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsed with pure water, and spin-dried. Further, the remaining water was removed by heating at 90 ° C. for 90 seconds to obtain a second resist pattern 2a having a pitch of 100 nm and a line width of 50 nm (FIG. 1 (i)).
The obtained pattern was evaluated by the following evaluation methods, and the results are summarized in Table 6 below.

The resist compositions and surface treatment agents used in Examples 1 to 5 are as follows.
As Comparative Example 1, a resist pattern 1 and a resist pattern 2 were formed without performing surface treatment. The pattern forming method was performed according to the above method except that the surface treatment was not performed.

〔Evaluation methods〕
(Evaluation of pattern line width)
In the resist pattern created by the above method, the line width (x [nm]) of the resist pattern 1a in FIG. 1C and the line width (y [nm]) of the resist pattern 1b in FIG. The line width variation before and after the formation of the second resist pattern in the first resist pattern was evaluated from the difference (y−x [nm]).

  The line width is measured using a length-measuring scanning electron microscope (SEM), and the pattern is observed. A length-measuring SEM (Hitachi, Ltd., S-9380II) is measured in the range where the edge in the longitudinal direction of the line pattern is 0.7 μm. ), The line width was measured at 50 points, and the average was calculated.

(Evaluation of line edge roughness (LER))
In the resist pattern created by the above method, the LER (s [nm]) of the resist pattern 1a in FIG. 1C and the LER (t [nm]) of the resist pattern 1b in FIG. The LER fluctuation before and after formation of the second resist pattern in the first resist pattern was evaluated from the difference (ts [nm]).

The LER is measured by observing the pattern using a scanning electron microscope (SEM), and measuring the distance from the reference line where the edge in the longitudinal direction of the line pattern should be 0.7 μm. 50 points were measured by (Hitachi, Ltd. S-9380II), the standard deviation was obtained, and 3σ was calculated. The results are shown in the table. A smaller value indicates better performance.

  From the above results, it can be seen that the surface treatment agent developed in the present invention is excellent as a freezing agent.

The schematic process drawing explaining the pattern formation method used in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st resist film, 2 ... 2nd resist film, 3 ... Surface treatment agent (freezing agent), 4 ... Antireflection film, 5 ... Silicon wafer, 10 ... Surface treatment agent film, 1a ... first resist pattern, 1b ... first resist pattern (freezing treatment completed), 2a ... second resist pattern, m1, m2 ... mask, n ···nozzle

Claims (7)

  A surface treatment agent for forming a resist pattern, comprising a compound having an oxazoline group.   The surface treatment agent for forming a resist pattern according to claim 1, wherein the compound having an oxazoline group is an oxazoline group-containing polymer.   The surface treatment agent for forming a resist pattern according to claim 1 or 2, further comprising a compound having an oxazoline group and a polymer inert to the resist pattern.   Furthermore, surfactant is contained, The surface treatment agent for resist pattern formation of any one of Claims 1-3 characterized by the above-mentioned.   A first resist in a resist pattern having a first resist pattern formed from a first resist film and a second resist pattern formed from a second resist film formed on the first resist pattern It is a surface treatment agent for pattern formation, The surface treatment agent for resist pattern formation of any one of Claims 1-4 characterized by the above-mentioned.   Forming a first resist pattern on the first resist film; forming a second resist film on the first resist pattern obtained in the step; In the resist pattern formation method including the 2nd resist pattern formation process which forms a 2nd resist pattern on a film, between the 1st resist pattern formation process and the 2nd resist pattern formation process, Claims 1- A method for forming a resist pattern, comprising a step of processing the first resist pattern using the surface treating agent according to any one of 5 above.   A heating process is further included between the process of surface-treating a 1st resist pattern using the surface treating agent of any one of Claims 1-5, and a 2nd resist pattern formation process. The method for forming a resist pattern according to claim 6, wherein the method is characterized in that:

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