JP2010020204A - Radiation-sensitive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition suitably usable as a chemically amplified resist and excellent in storage stability. <P>SOLUTION: The radiation-sensitive resin composition includes: (A) an acid generator represented by general formula (1-1) or general formula (1-2); (B) an acid diffusion inhibitor represented by general formula (2); and (C) a copolymer. In the general formulae (1-1) and (1-2), R<SP>1</SP>denotes alkyl or the like; M<SP>+</SP>denotes a monovalent cation; R<SP>1a</SP>and R<SP>1b</SP>each independently denote an organic group or the like; and Y denotes a divalent organic group or the like. In the general formula (2), R<SP>2</SP>, R<SP>3</SP>and R<SP>4</SP>are alkyl or the like. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radiation-sensitive resin composition, and more specifically, uses various types of radiation such as deep ultraviolet rays such as KrF excimer laser or ArF excimer laser, X-rays such as synchrotron radiation, and charged particle beams such as electron beams. The present invention relates to a radiation sensitive resin composition that can be suitably used as a chemically amplified resist useful for fine processing.

In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, far ultraviolet rays such as KrF excimer laser, ArF excimer laser, F ₂ excimer laser or EUV (extreme ultraviolet), There is a need for a lithography technique capable of fine processing at a level of about 100 nm or less using X-rays such as synchrotron radiation or charged particle beams such as electron beams. As such a radiation-sensitive resin composition suitable for radiation, a chemically amplified sensitization utilizing the chemical amplification effect of a component having an acid-dissociable functional group and an acid generator that is a component that generates acid upon irradiation with radiation. Many radiation compositions have been proposed. For example, a high-molecular compound for photoresist using a polymer having a specific structure including a monomer unit having a norbornane ring derivative as a resin component is known (see Patent Document 1 and Patent Document 2). Further, a radiation-sensitive resin composition in which a photoactive compound is further added to a component having an acid-dissociable functional group and an acid generator in order to improve sensitivity and resolution is disclosed (see Patent Document 3).
JP 2002-201232 A JP 2002-145955 A JP 2002-363123 A

  However, when a higher degree of integration is required in the semiconductor field, the radiation-sensitive resin composition that is a resist has a higher balance of lithography performance, in particular, the depth of focus of dense patterns and isolated patterns, LWR (Line Width Roughness). In addition, a resist having an excellent balance of MEEF (Mask Error Enhancement Factor) has been required. At the same time, it is necessary that the radiation-sensitive resin composition having an excellent balance of these performances can be actually industrially implemented, and a radiation-sensitive resin composition having particularly excellent storage stability is desired. With the progress of miniaturization in the semiconductor industry, there is an urgent need to develop such a radiation-sensitive resin composition that is excellent in depth of focus and LWR and has good storage stability.

  Since the acid generators of the general formulas (1-1) and (1-2) described later are partially substituted with fluorine at the α, β-positions, they exhibit strong acidity and can easily introduce various substituents. In addition, since the range of molecular design is large, a radiation sensitive resin composition having good compatibility with various resin types can be produced by devising the molecular design. In particular, since it has an ester bond in the molecule, it is possible to produce a radiation-sensitive resin composition having good compatibility with the meth (a) acrylic acid ester polymer. However, the radiation sensitive resin composition using this acid generator is not practical because of poor storage stability.

  The present invention has been made to address the above-mentioned problems, and an object of the present invention is to provide a radiation-sensitive resin composition that is a chemically amplified resist having excellent depth of focus and LWR, as well as excellent storage stability. There is to do.

  As a result of intensive studies on the above problems, the inventors of the present invention hydrolyze the ester bond sites of the acid generators represented by the general formulas (1-1) and (1-2). Hypothesized that would worsen and examined. As a result, the combination of the acid generator and the acid diffusion inhibitor represented by the general formula (2) is excellent in storage stability, and has a good balance of dense pattern / isolated pattern focal depth, LWR, and MEEF. It discovered that it was effective as a composition, and came to make this invention. That is, this invention provides the following radiation sensitive resin composition.

[1] (A) an acid generator represented by the following general formula (1-1) or general formula (1-2); (B) an acid diffusion inhibitor represented by the following general formula (2); (C) A radiation sensitive resin composition comprising a copolymer.

[In General Formula (1-1), R ¹ represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, or a heteroaryl group having 4 to 15 carbon atoms, and M ⁺ represents a monovalent cation. . In the general formula (1-2), ^{R 1} has the same meaning as ^{R 1} in the general formula (1-1). R ^1a and R ^1b each independently represent a hydrogen atom or a substituted or unsubstituted monovalent organic group, or R ^1a and R ^1b form a ring together with the carbon atoms to which they are bonded to each other; Y represents a single bond, a double bond or a divalent organic group. ]

[In General Formula (2), R ² , R ³ and R ⁴ are each a hydrogen atom or an optionally substituted alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms. Yes, R ² , R ³ and R ⁴ may be bonded to each other to form a ring structure having 5 to 15 constituent atoms. ]

[2] The radiation-sensitive resin composition according to [1] R ⁴ is a t- butyl group in the general formula (2).

[3] The radiation-sensitive resin composition according to the above [1] or [2], wherein in the general formula (1-1), M ⁺ is a sulfonium cation or an iodonium cation.

[4] The radiation-sensitive resin composition according to any one of [1] to [3], wherein the (C) copolymer has a repeating unit represented by the following general formula (3).

[In General Formula (3), R ⁵ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ⁶ represents a linear or branched alkyl group having 1 to 5 carbon atoms. n = 1-4. ]

[5] The radiation-sensitive resin composition according to any one of [1] to [4], wherein (C) the proportion of the repeating unit having a tertiary ester as a partial structure in the copolymer is 50 to 70 mol%. object.

The radiation-sensitive resin composition of the present invention is excellent in transparency to actinic radiation, for example, far-ultraviolet rays and electron beams represented by KrF excimer laser, ArF excimer laser, F ₂ excimer laser or EUV, and these actinic radiations. As a practical and useful radiation-sensitive resin composition, there is no problem in storage stability with a good balance of depth of focus, LWR, and MEEF of dense and isolated patterns. Is preferred.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiments, and the ordinary knowledge of those skilled in the art is within the scope of the present invention. Based on the above, it should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

Radiation sensitive resin composition:
The radiation sensitive resin composition of the present invention comprises (A) an acid generator represented by general formula (1-1) or (1-2), and (B) an acid diffusion represented by general formula (2). An inhibitor is an essential component.

In [Formula (1-1), ^{R 1} represents an alkyl group, an aryl group or a heteroaryl group having from 4 to 15 carbon atoms of 6 to 15 carbon atoms having 1 to 20 carbon atoms. M ⁺ represents a monovalent cation. In the general formula (1-2), ^{R 1} has the same meaning as ^{R 1} in the general formula (1-1). R ^1a and R ^1b each independently represent a hydrogen atom or a substituted or unsubstituted monovalent organic group, or R ^1a and R ^1b form a ring together with the carbon atoms to which they are bonded to each other; Y represents a single bond, a double bond or a divalent organic group. ]

[In formula (2), with R ^{2, R 3,} R ⁴ is a hydrogen atom or each same or different substituted carbon atoms and optionally 1 to 20 alkyl group or an aryl group having 6 to 20 carbon atoms Yes, R ² , R ³ and R ⁴ may be bonded to each other to form a ring structure having 5 to 15 constituent atoms. ]

[Acid generator (A)]
R ¹ in the above formula (1-1) is preferably tert-butyl group, cyclohexyl group, 1-adamantyl group, phenyl group, 4-tert-butylphenyl group, 4-biphenyl group, 1-naphthyl group, 2 -A naphthyl group, 2-furanyl group, 2-propenyl group, etc. are mentioned. Preferred examples of ^{R 1} in the formula (1-2) is the same as ^{R 1} of formula (1-1). In the general formula (1-2), examples of the preferable imide group bonded to the sulfonyloxy group (SO ₂ —O—) in the formula include groups represented by the following formulas (iii-1) to (iii-9). Can be mentioned.

  Among these imide groups, for example, a group represented by the formula (iii-1), formula (iii-4), formula (iii-8), or formula (iii-9) is preferable.

[Acid diffusion inhibitor (B)]
Preferred examples of R ² and R ³ in the above formula (2) are given below.

R ⁴ in the above formula (2) is preferably a methyl group, ethyl group, isopropyl group, tert-butyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, phenyl group, 4-tert-butylphenyl group. 4-biphenyl group, 1-naphthyl group, 2-naphthyl group and 2-furanyl group, more preferably tert-butyl group.

[Sulphonium salt]
The sulfonium salt that can be used in the present invention is represented by the following general formula (4).

Wherein, ^{R 1} has the same meaning as ^{R 1} in the general formula (1-1). R ⁷ , R ⁸ and R ⁹ are each independently a substituted or unsubstituted linear or branched alkyl group, alkenyl group or oxoalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted carbon number of 6 to 18 aryl group, or an aralkyl group or an aryl oxoalkyl group, or R ^7, any two or more of R ⁸ and R ⁹ are bonded to each other forms a ring with the sulfur atom May be. ]

  Preferred examples of the sulfonium cation of the formula (4) are those represented by the following general formulas (4-1) and (4-2).

[In General Formula (4-1), a plurality of R ^a , R ^b , and R ^c may be the same or different from each other, and R ^a , R ^b , and R ^c are each a hydrogen atom, substituted, or unsubstituted. A linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or two or more of R ^a , R ^b , and R ^c are They are bonded to each other to form a ring. q1, q2, and q3 each independently represents an integer of 0 to 5. In the general formula (4-2), a plurality of R ^d and R ^e may be the same or different from each other, and R ^d is a hydrogen atom, a substituted or unsubstituted C 1-8 linear or branched alkyl group or a substituted or unsubstituted aryl group having 6 to 8 carbon atoms, or two or more R ^d is bonded to form a ring to each other. R ^e is a hydrogen atom, a substituted or unsubstituted, straight or branched alkyl group having 1 to 7 carbon atoms or a substituted or unsubstituted aryl group having 6 to 7 carbon atoms, or 2 or more, R ^e is bonded to each other to form a ring. q4 represents an integer of 0 to 7, q5 represents an integer of 0 to 6, and q6 represents an integer of 0 to 3. ]

  Examples of the preferred sulfonium cation of the general formula (4-1) or the general formula (4-2) include the following formulas (i-1) to (i-64).

  Among these preferred sulfonium cations, for example, the formula (i-1), formula (i-2), formula (i-6), formula (i-8), formula (i-13), formula (i- 19), sulfonium cation represented by formula (i-25), formula (i-27), formula (i-29), formula (i-33), formula (i-51) and formula (i-54) Is more preferable.

[Iodonium salt]
In the present invention, an iodonium salt can also be used. The iodonium salt that can be used in the present invention is represented by the following general formula (5).

^{Wherein, R 1,} R ^7, and ^{R 8} have the same meanings as ^R 1, ^{R 7,} and ^{R 8} in the general formula (4). ]

  A preferred example of the iodonium cation of the formula (5) is represented by the following general formula (5-1).

[In the general formula (5-1), a plurality of R ^f and R ^g may be the same or different from each other, and R ^f and R ^g are each a hydrogen atom, a substituted or unsubstituted C 1-12, A linear or branched alkyl group, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or two or more ^Rf and ^Rg are bonded to each other to form a ring; . q7 and q8 each independently represents an integer of 0 to 5. ]

  Preferred examples of the iodonium cation represented by the general formula (5-1) include the following formulas (ii-1) to (ii-39).

  Among these preferable iodonium cations, for example, iodonium cations represented by the above formulas (ii-1) and (ii-11) are more preferable.

[Copolymer (C)]
The radiation-sensitive resin composition of the present invention further includes a copolymer having the following general formula (3) as a repeating unit as the component (C).

In [general formula (3), R ⁵ represents a hydrogen atom, a methyl group, a trifluoromethyl group, R ⁶ represents a linear or branched alkyl group having 1 to 5 carbon atoms. n = 1-4. ]

R ⁶ in the general formula (3) is preferably a methyl group, an ethyl group or an isopropyl group.

  The copolymer (C) in the radiation-sensitive resin composition of the present invention preferably has a ratio of repeating units having a tertiary ester as a partial structure of 50 to 70 mol%.

  Among repeating units having a tertiary ester as a partial structure, preferred examples are shown in the following general formulas (3-1) to (3-11).

[In the formulas (3-1) to (3-11), R represents a hydrogen atom, a methyl group, or a trifluoromethyl group. ]

The copolymer (C) may further have other repeating units. Specific examples of the monomer that can constitute another repeating unit include α- (meth) acryloyloxy-γ-butyrolactone, β- (meth) acryloyloxy-γ-butyrolactone, α- (meth) acryloyloxy-β. -Fluoro-γ-butyrolactone, α- (meth) acryloyloxy-β-hydroxy-γ-butyrolactone, α- (meth) acryloyloxy-β-methyl-γ-butyrolactone, α- (meth) acryloyloxy-β-ethyl -Γ-butyrolactone, α- (meth) acryloyloxy-β, β-dimethyl-γ-butyrolactone, α- (meth) acryloyloxy-β-methoxy-γ-butyrolactone, α-fluoro-β- (meth) acryloyloxy -Γ-butyrolactone, α-hydroxy-β- (meth) acryloyloxy-γ-butyrolactone , Α-methyl-β- (meth) acryloyloxy-γ-butyrolactone, α-ethyl-β- (meth) acryloyloxy-γ-butyrolactone, α, α-dimethyl-β- (meth) acryloyloxy-γ-butyrolactone , Α-methoxy-β- (meth) acryloyloxy-γ-butyrolactone, α- (meth) acryloyloxy-δ-valerolactone, β- (meth) acryloyloxy-δ-valerolactone, δ- (meth) acryloyloxy -Γ-valerolactone, δ- (meth) acryloyloxy-β-methyl-γ-valerolactone, δ- (meth) acryloyloxy-β, β-dimethyl-γ-valerolactone, 2- (meth) acryloyloxy- 5-oxo-4-oxatricyclo [4.2.1.0 ^3,7] nonane, 2- (meth) acryloyloxy 9-methoxycarbonyl-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7] nonane, 4- (meth) acryloyloxy-7-oxo-6-oxabicyclo [3.2.1 ] Octane, 4- (meth) acryloyloxy-2-methoxycarbonyl-7-oxo-6-oxabicyclo [3.2.1] octane, 8 (9)-(meth) acryloyloxy-3-oxo-4- Oxatricyclo [5.2.1.0 ^2,6 ] decane, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylic acid, methacrylic acid, 3-hydroxyadamantyl methacrylate, 3-hydroxyadamantyl acrylate, 3- ( 2-Hydroxy) ethyl-1-adamantyl (meth) acrylate, 2-hexahydrophthaloylethyl Methacrylate, p-hydroxystyrene, α-methyl-p-hydroxystyrene, p-acetoxystyrene, α-methyl-p-acetoxystyrene, p-benzyloxystyrene, p-tert-butoxystyrene, p-tert-butoxycarboni Loxystyrene, p-tert-butyldimethylsiloxystyrene, diethyl maleate, diethyl fumarate, diethyl itaconate, phenyl (meth) acrylate, benzyl (meth) acrylate, styrene, α-methylstyrene, m-methylstyrene, p- Methylstyrene, vinyltoluene, p-methoxystyrene, pt-butoxystyrene, t-butyl (meth) acrylate, 4,4,4-trifluoro-3-hydroxy-1-methyl-3-trifluoromethyl-1 -Butyl (meth) Acrylate, acrylonitrile, methacrylonitrile, mention may be made of acrylamide and methacrylamide.

  The copolymer (C) can be synthesized according to a conventional method such as radical polymerization. For example, a reaction solution containing each monomer and a radical initiator can be used as a reaction solution or a reaction solution containing a monomer. The reaction solution containing each monomer and the reaction solution containing the radical initiator are dropped separately into the reaction solution containing the reaction solvent or the monomer, respectively. In addition, a polymerization reaction is performed by dropping a reaction solution containing each monomer separately and a reaction solution containing a radical initiator into a reaction solution containing each reaction solvent or monomer separately. The method of making it preferable is.

  The reaction temperature in each of the above reactions can be appropriately set depending on the type of initiator, but is generally 30 ° C to 180 ° C. Preferably it is 40 to 160 degreeC, More preferably, it is 50 to 140 degreeC. The time required for dropping can be variously set depending on the reaction temperature, the type of initiator, and the monomer to be reacted, but is 30 minutes to 8 hours. Preferably it is 45 minutes-6 hours, More preferably, it is 1 hour-5 hours. Moreover, although the total reaction time including dripping time can be variously set like the above, it is 30 minutes-8 hours. Preferably it is 45 minutes-7 hours, More preferably, it is 1 hour-6 hours. When dropping into a solution containing monomers, the monomer content in the dropped solution is preferably 30 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol based on the total amount of monomers used for polymerization. % Or more.

  Examples of the radical initiator used in the polymerization include 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2-cyclopropylpropionitrile), 2, 2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane- 1-carbonitrile), 2,2′-azobis (2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2′-azobis (2-methyl-N-2-propenylpropionamidine) dihydrochloride, 2, 2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis {2-methyl-N [1,1-bis (hydroxymethyl) 2-hydroxyethyl] propionamide}, dimethyl-2,2′-azobis (2-methylpropionate), 4,4′-azobis (4-cyanovaleric acid) And 2,2′-azobis (2- (hydroxymethyl) propionitrile). These initiators can be used alone or in admixture of two or more.

  The solvent used for the polymerization can be used unless it dissolves the monomers used and inhibits the polymerization (inhibition of polymerization (eg, nitrobenzenes, chain transfer, eg, mercapto compound)). Examples include alcohols, ethers, ketones, amides, esters and lactones, and nitriles and mixtures thereof. Examples of alcohols include methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and 1-methoxy-2-propanol. Examples of ethers include propyl ether, isopropyl ether, butyl methyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane and 1,3-dioxane. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, and methyl isobutyl ketone. Examples of amides include N, N-dimethylformamide and N, N-dimethylacetamide. Esters and lactones include ethyl acetate, methyl acetate, isobutyl acetate and γ-butyrolactone. Examples of nitriles include acetonitrile, propionitrile, and butyronitrile. These solvents can be used alone or in admixture of two or more.

  As described above, after the polymerization reaction, the obtained resin is preferably recovered by a reprecipitation method. That is, after the polymerization is completed, the reaction solution is put into a reprecipitation solvent, and the target resin is recovered as a powder. Examples of the reprecipitation solvent include water, alcohols, ethers, ketones, amides, esters and lactones, and nitriles alone and a mixture thereof. Examples of alcohols include methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, propylene glycol and 1-methoxy-2-propanol. Examples of ethers include propyl ether, isopropyl ether, butyl methyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane and 1,3-dioxane. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, and methyl isobutyl ketone. Examples of amides include N, N-dimethylformamide and N, N-dimethylacetamide. Esters and lactones include ethyl acetate, methyl acetate, isobutyl acetate and γ-butyrolactone. Examples of nitriles include acetonitrile, propionitrile, and butyronitrile.

  The copolymer (C) contained in the radiation-sensitive resin composition of the present embodiment has a weight average molecular weight (hereinafter referred to as “Mw”) measured by gel permeation chromatography of 1,000 to 100,000. It is preferably 1,500 to 80,000, more preferably 2,000 to 50,000. If the Mw of the resin is less than 1,000, heat resistance when a resist is formed may be reduced. On the other hand, if it exceeds 100,000, the developability when a resist is formed may be lowered. Further, the ratio (Mw / Mn) of Mw and number average molecular weight (hereinafter referred to as “Mn”) of the resin is preferably 1 to 5, and more preferably 1 to 3.

  In addition, the polymerization reaction liquid obtained by the above polymerization is preferably as less as possible for impurities such as halogen and metal, and when there are few impurities, the sensitivity, resolution, process stability, pattern shape, etc. when forming a resist can be further improved. Can do. Examples of the resin purification method include chemical purification methods such as washing with water and liquid-liquid extraction, and combinations of these chemical purification methods with physical purification methods such as ultrafiltration and centrifugation. . In this invention, the said resin can be used individually or in mixture of 2 or more types.

  Here, the radiation sensitive resin composition of the present invention comprises (A) an acid generator and (B) an acid diffusion inhibitor as essential components. Further, the radiation sensitive resin composition of the present invention comprises (C) a copolymer, and optionally contains (D) a solvent, and further contains (E) an additive, if necessary. Type radiation sensitive resin composition.

  The (A) acid generator used in the present invention is as described above, and the blending amount thereof is 0.1 to 20 parts, particularly 100 parts by weight of the radiation-sensitive base resin (parts by mass, hereinafter the same), 1 to 15 parts.

  The acid diffusion inhibitor (B) used in the present invention is as described above, and can be used singly or in combination of two or more, and the blending amount is 0.001 with respect to 100 parts of the base resin. ~ 3 parts, particularly 0.01-2 parts are preferred. If the blending amount is less than 0.001 part, there is no blending effect, and if it exceeds 3 parts, the sensitivity may be too low.

  The (C) copolymer used by this invention is as above-mentioned, and can be used individually by 1 type or in combination of 2 or more types. The blending ratio is set so that the total amount of the copolymer in the radiation-sensitive resin composition is 100 parts. However, the compounding quantity of (C) copolymer is 50-100 parts.

  The organic solvent (D) used in the present invention may be any organic solvent that can dissolve the base resin, the acid generator, other additives, and the like. Examples of such an organic solvent include ketones such as cyclohexanone and methyl amyl ketone;

Alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol;

Ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether;

Propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol Esters such as mono-tert-butyl ether acetate;

Examples thereof include lactones such as γ-butyrolactone, and one kind of these can be used alone, or two or more kinds can be mixed and used, but the invention is not limited thereto.

  In the present invention, among these organic solvents, diethylene glycol dimethyl ether, 1-ethoxy-2-propanol, propylene glycol monomethyl ether acetate, cyclohexanone, and γ-butyrolactone are excellent in solubility of the acid generator in the resist component and in good coatability. And mixed solvents thereof are preferably used.

  The amount of the organic solvent used is preferably 200 to 4,000 parts, particularly 500 to 3,000 parts, based on 100 parts of the base resin.

  The additive (E) can be added to the chemically amplified resist material of the present invention. Examples of the additive (E) include surfactants for improving applicability, additives such as a light-absorbing material for reducing irregular reflection from the substrate, and water repellents for immersion exposure.

  Examples of surfactants include, but are not limited to, polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene steryl ether, polyoxyethylene cetyl ether and polyoxyethylene olein ether;

Polyoxyethylene alkyl allyl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether;

Polyoxyethylene polyoxypropylene block copolymers;

Sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate and sorbitan monostearate;

Nonionic interfaces of polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate and polyoxyethylene sorbitan tristearate Active agent;

EFTOP EF301, EF303, EF352 (Gemco), MegaFuck F171, F172, F173, R08, R30 (Dainippon Ink & Chemicals), Florard FC-430, FC-431, FC-4430, FC-4432 (Manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-381, S-382, SC101, SC102, SC103, SC104, SC105, SC106, Surfynol E1004, KH-10, KH-20, KH-30 and KH Fluorosurfactants such as -40 (Asahi Glass Co., Ltd.);

Organosiloxane polymers KP341, X-70-092, X-70-093 (manufactured by Shin-Etsu Chemical Co., Ltd.), acrylic acid-based or methacrylic acid-based polyflow No. 75 and no. 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.), among which FC-430, Surflon S-381, Surfynol E1004, KH-20 and KH-30 are preferred. These can be used alone or in combination of two or more.

  The addition amount of the surfactant in the chemically amplified resist material of the present invention is 0.01 to 10 parts, preferably 0.1 to 5 parts, relative to 100 parts of the base resin in the resist material.

  Furthermore, an ultraviolet absorber can be blended with the chemically amplified resist material of the present invention. Although not particularly limited, those described in JP-A-11-190904 can be used, and preferably bis (4-hydroxyphenyl) sulfoxide, bis (4-tert-butoxyphenyl) sulfoxide, bis (4 Diaryl sulfoxide derivatives such as tert-butoxycarbonyloxyphenyl) sulfoxide and bis [4- (1-ethoxyethoxy) phenyl] sulfoxide;

Bis (4-hydroxyphenyl) sulfone, bis (4-tert-butoxyphenyl) sulfone, bis (4-tert-butoxycarbonyloxyphenyl) sulfone, bis [4- (1-ethoxyethoxy) phenyl] sulfone and bis [4 Diarylsulfone derivatives such as-(1-ethoxypropoxy) phenyl] sulfone;

Diazo compounds such as benzoquinone diazide, naphthoquinone diazide, anthraquinone diazide, diazofluorene, diazotetralone and diazophenantrone;

Naphthoquinone-1,2-diazide-5-sulfonic acid chloride and 2,3,4-trihydroxybenzophenone complete or partial ester compound and naphthoquinone-1,2-diazido-4-sulfonic acid chloride with 2,4,4 Quinonediazide group-containing compounds such as complete or partial ester compounds with '-trihydroxybenzophenone;

Tert-butyl 9-anthracenecarboxylate, tert-amyl 9-anthracenecarboxylate, tert-methoxymethyl 9-anthracenecarboxylate, tert-ethoxyethyl 9-anthracenecarboxylate, 2-tert-tetrahydropyranyl 9-anthracenecarboxylate And 9-anthracenecarboxylic acid 2-tert-tetrahydrofuranyl.

  The blending amount of the ultraviolet absorber may or may not be added depending on the type of the resist material, but when added, it is 0.01 to 10 parts, more preferably 0.1 to 100 parts of the base resin. ~ 5 parts.

  As an example of the water repellent, a generally known water repellent can be used. Examples thereof include perfluoropolyethers described in JP-A No. 2004-259040, silicon-based / fluorine-based water repellents described in JP-A 2006-309245 or WO 07/116664.

  The blending amount of the water repellent agent may or may not be added depending on the type of the resist material, but when added, it is 0.01 to 15 parts, more preferably 0.1 to 100 parts of the base resin. -10 parts.

Photoresist pattern formation method:
The radiation sensitive resin composition of this embodiment is particularly useful as a chemically amplified resist. For example, in the case of a positive resist, when a resist film is formed with the radiation-sensitive resin composition of the present embodiment, from the acid generator represented by the general formula (1-1) or (1-2) described above by exposure. The acid-dissociable group in the resin having a repeating unit is dissociated by the action of the generated acid (including an acid generated from another acid generator when other acid generators are blended), resulting in a carboxyl group. As a result, the solubility of the exposed portion of the resist in the alkaline developer is increased, and the exposed portion is dissolved and removed by the alkaline developer to obtain a positive resist pattern.

  When forming a resist pattern from the radiation-sensitive resin composition of the present embodiment, first, the above-mentioned acid generator and, if necessary, the above-mentioned other acid generator and the resin having the above repeating unit are used as the solvent. The composition solution can be obtained by, for example, filtering it through a filter having a pore size of about 200 nm after being uniformly dissolved in the solution. In addition, the amount of the solvent at this time is preferably such an amount that the concentration of the total solids is 0.1 to 50% by mass, and more preferably 1 to 40% by mass. . By setting it as such a density | concentration, filtration can be performed smoothly.

  Next, the obtained composition solution is applied onto a substrate such as a silicon wafer or a wafer coated with aluminum by an appropriate application means such as spin coating, cast coating, or roll coating. A resist film is formed. Thereafter, in some cases, after heat treatment (hereinafter referred to as “SB”) in advance, the resist film is exposed to form a predetermined resist pattern. In addition, visible rays, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams and the like are appropriately selected and used as the radiation used at that time, but ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength Far ultraviolet rays represented by 248 nm) are preferable, and ArF excimer laser (wavelength 193 nm) is particularly preferable. Further, it is preferable to perform a heat treatment (hereinafter referred to as “PEB”) after exposure. By this PEB, the dissociation reaction of the acid dissociable group in the resin proceeds smoothly. The heating conditions for PEB vary depending on the composition of the radiation-sensitive resin composition, but are preferably 30 to 200 ° C, and more preferably 50 to 170 ° C.

  The radiation-sensitive resin composition of the present embodiment has an organic system on the substrate to be used, for example, as disclosed in Japanese Patent Publication No. 6-12452, etc., in order to maximize the potential. Alternatively, an inorganic antireflection film can be formed. Further, in order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film can be provided on the resist film as disclosed in, for example, JP-A-5-188598. These techniques can be used in combination.

  Next, the exposed resist film is developed to form a predetermined resist pattern. Examples of the developer used for development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n-propylamine. , Triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene and 1,5-diazabicyclo- [4.3.0] An alkaline aqueous solution in which at least one of alkaline compounds such as 5-nonene is dissolved is preferable. The concentration of the alkaline aqueous solution is preferably 10% by mass or less. If the concentration of the alkaline aqueous solution is more than 10% by mass, the unexposed area may be dissolved in the developer.

  Further, for example, an organic solvent can be added to the developer. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, methyl i-butyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone and 2,6-dimethylcyclohexanone; methyl alcohol, ethyl alcohol, n-propyl Alcohols such as alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol and 1,4-hexanedimethylol; ethers such as tetrahydrofuran and dioxane Esters such as ethyl acetate, n-butyl acetate and i-amyl acetate; aromatic hydrocarbons such as toluene and xylene; phenol, acetonyl acetone and dimethylformamide; Can.

  In addition, these organic solvents can be used individually or in mixture of 2 or more types. It is preferable that the usage-amount of an organic solvent is 100 volume% or less with respect to the said alkaline aqueous solution. If the amount of the organic solvent used is more than 100% by volume, the developability is lowered, and there is a risk that the remaining development in the exposed area will increase. An appropriate amount of a surfactant or the like can be added to the developer. In addition, after developing with the said developing solution, it is preferable to wash | clean and dry with water.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

"Resin synthesis"
Example 1
The following compound (S-3) 24.92 g (31 mol%), the following compound (S-7) 34.72 g (31 mol%), the following compound (S-11) 40.36 g (38 mol%) -A monomer solution prepared by dissolving 3.92 g of dimethyl 2,2'-azobis (2-methylpropionate) in 200 g of butanone was prepared. A 1000 ml three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. After purging with nitrogen, the reactor was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was added using a dropping funnel. The solution was added dropwise over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was dispersed in 400 g of methanol and washed in the form of a slurry, followed by filtration, followed by filtration twice, followed by drying at 50 ° C. for 17 hours to obtain a white powder copolymer (resin ( C-1)) was obtained (72 g, 72 yield%). This copolymer has Mw of 5,841 and Mw / Mn = 1.40, and as a result of ¹³ C-NMR analysis, the compound (S-3), compound (S-7), and compound (S-11) are The content of each repeating unit represented was a copolymer of 30:30:40 (mol%). This copolymer is referred to as “polymer (C-1)”.

  Each measurement and evaluation in each example and comparative example was performed as follows.

(sensitivity)
Using a silicon wafer (ARC29) having an ARC29 (Brewer Science) film with a film thickness of 770 angstroms formed on the wafer surface, each composition solution was applied onto the substrate by spin coating, and then on a hot plate. In the resist film having a film thickness of 0.12 μm formed by performing SB for 60 seconds under the conditions shown in Table 2, an ArF excimer laser exposure apparatus (numerical aperture of 0.78) manufactured by Nikon Corporation was used to pass through the mask pattern. Exposed. Thereafter, PEB was performed for 60 seconds under the conditions shown in Table 2, and then developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 25 ° C. for 30 seconds, washed with water, and dried to form a positive resist pattern. Formed. At this time, an exposure amount for forming a line-and-space pattern (1L1S) having a line width of 90 nm in a one-to-one line width was defined as an optimum exposure amount, and this optimum exposure amount was defined as sensitivity.

(Dense line depth of focus)
The focus fluctuation width when the pattern dimension resolved in the 90 nm 1L / 1S mask pattern is within ± 10% of the mask design dimension was defined as the dense line focal depth.

(Isolated line depth of focus)
The focus fluctuation width when the 90 nm1L / 1400 nmP pattern dimension resolved in the 140 nm1L / 1400 nmP mask pattern falls within the range of 81 to 99 nm1L / 1400 nmP was defined as the isolated line focal depth.

(LWR)
When observing the 90 nm 1L / 1S pattern resolved at the optimum exposure dose, when observing from the top of the pattern with Hitachi SEM: S9220, the line width was observed at 10 arbitrary points, and the measurement variation was 3 The value expressed in sigma was defined as LWR.

(MEEF)
The optimal exposure dose sensitivity was measured using a mask having a line width of 90 nm so that the line width of the 90 nm 1L / 1S pattern was 90 nm, and then the sensitivity was 85.0 nm, 87.5 nm, 90.0 nm, 92. The pattern dimensions resolved at the mask size at 5 points of 5 nm and 95.0 nm were measured. The result was taken as the mask size on the horizontal axis and the line width on the vertical axis, and the gradient obtained by the least square method was defined as MEEF.

(Storage stability)
The value obtained by dividing the “initial sensitivity” by the difference between the “initial sensitivity” of the composition solution and the “sensitivity measured after storage at 5 ° C. for 2 weeks” was expressed as a percentage. A value within this range of 0% to ± 2% was considered good, and a value outside the range was regarded as bad.

  100 parts of the obtained polymer (C-1), 10.5 parts of the following radiation sensitive acid generator (acid generator) (A-2), and 0.7 parts of the following acid diffusion controller (B-6) Were mixed to obtain a radiation sensitive resin composition. 1200 parts of the following solvent (D-1) and 500 parts of the following solvent (D-2) are mixed to prepare a mixed solvent, and the resulting radiation-sensitive resin composition is dissolved in the mixed solvent to produce a radiation-sensitive material. A functional resin composition solution was obtained. In addition, the compounding quantity of each solvent is shown by the mass ratio (mass part) with respect to 100 parts of polymers (C-1). Each measurement was performed using the obtained radiation-sensitive resin composition solution. The measurement results are shown in Table 2.

Acid generator (A);

Acid diffusion controller (B);

Solvent (D);
(D-1): Propylene glycol monomethyl ether acetate (D-2): Cyclohexanone

  A polymer (resin (C)) (C-2 to 9) was prepared with each molar ratio of the compound (S-1) and the like shown in the following “copolymer (resin (C))”. Example 1 except that each of the obtained polymers (C-2 to 9) was mixed with the radiation-sensitive acid generator (A) and the acid diffusion controller (B) in the ratios shown in Table 1. In the same manner as described above, radiation-sensitive resin compositions (Examples 2 to 11 and Comparative Examples 1 to 7) were produced. The obtained radiation sensitive resin composition was dissolved in a mixed solvent in which the solvent (D) was mixed at a mixing ratio shown in Table 1 to obtain a radiation sensitive resin composition solution. In Table 1, “resin” means “copolymer (resin (C))”. Each measurement was performed using the obtained radiation-sensitive resin composition solution. The measurement results are shown in Table 2.

Copolymer (resin (C));
C-2: (S-4) / (S-7) / (S-11) = 35/35/30 (molar ratio), Mw = 5,073, Mw / Mn = 1.41
C-3: (S-1) / (S-2) / (S-11) = 25/25/50 (molar ratio), Mw = 7,437, Mw / Mn = 1.49
C-4: (S-4) / (S-8) / (S-11) = 35/15/50 (molar ratio), Mw = 6,869, Mw / Mn = 1.37
C-5: (S-6) / (S-11) / (S-12) = 50/35/15 (molar ratio), Mw = 6,189, Mw / Mn = 1.37
C-6: (S-8) / (S-11) / (S-12) = 50/15/35 (molar ratio), Mw = 5,355, Mw / Mn = 1.66
C-7: (S-5) / (S-10) / (S-11) = 40/10/50 (molar ratio), Mw = 5,482, Mw / Mn = 1.35
C-8: (S-9) / (S-11) / (S-12) = 25/30/45 (molar ratio), Mw = 6,824, Mw / Mn = 1.44
C-9: (S-8) / (S-11) / (S-12) = 40/10/50 (molar ratio), Mw = 7,351, Mw / Mn = 1.50

  From Table 2, it can be seen that all of the compositions of the present invention have excellent LWR and MEEF, and also have good storage stability. On the other hand, when components other than the component (B) of the present invention are used (Comparative Examples 1 to 6), the storage stability becomes insufficient. Moreover, when components other than the component (A) of the present invention are used (Comparative Example 7), LWR and MEEF are insufficient.

  The radiation sensitive resin composition of the present invention is useful as a chemically amplified resist. Especially used in lithography process using ArF excimer laser as a light source. In forming fine patterns of 90 nm or less, with a moderate sensitivity, a wide range of common DOFs for dense and isolated patterns, excellent LWR / MEEF, and good storage stability It can be used as a chemically amplified resist.

Claims (5)

(A) an acid generator represented by the following general formula (1-1) or general formula (1-2), (B) an acid diffusion inhibitor represented by the following general formula (2), and (C) A radiation-sensitive resin composition comprising a copolymer.

[In General Formula (1-1), R ¹ represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, or a heteroaryl group having 4 to 15 carbon atoms, and M ⁺ represents a monovalent cation. . In the general formula (1-2), ^{R 1} has the same meaning as ^{R 1} in the general formula (1-1). R ^1a and R ^1b each independently represent a hydrogen atom or a substituted or unsubstituted monovalent organic group, or R ^1a and R ^1b form a ring together with the carbon atoms to which they are bonded to each other; Y represents a single bond, a double bond or a divalent organic group. ]

[In formula (2), with R ^{2, R 3,} R ⁴ is a hydrogen atom or each same or different substituted carbon atoms and optionally 1 to 20 alkyl group or an aryl group having 6 to 20 carbon atoms Yes, R ² , R ³ and R ⁴ may be bonded to each other to form a ring structure having 5 to 15 constituent atoms. ] The radiation-sensitive resin composition according to claim 1 R ⁴ is a t- butyl group in the general formula (2). In the formula (1-1), the radiation-sensitive resin composition according to claim 1 or 2 M ⁺ is a sulfonium cation or an iodonium cation. The radiation sensitive resin composition as described in any one of Claims 1-3 in which the said (C) copolymer has a repeating unit represented by following General formula (3).

[In General Formula (3), R ⁵ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ⁶ represents a linear or branched alkyl group having 1 to 5 carbon atoms. n = 1-4. ]   Furthermore, the ratio of the repeating unit which has (C) tertiary ester in a copolymer as a partial structure is 50-70 mol%, The radiation sensitive resin composition as described in any one of Claims 1-4.