JP2009015194A - Method for forming pattern and pattern coating composition to be used for the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a pattern by which a finer pattern can be easily and efficiently formed. <P>SOLUTION: The method for forming a pattern includes steps of: (1) forming a first pattern on a substrate by using a first radiation-sensitive resin composition containing (a) a resin that becomes alkali-soluble by an effect of an acid and (b) a radiation-sensitive acid generator, and applying a pattern coating composition on the first pattern surface to form a coating layer; and (2) baking at least the coating layer to form a second pattern. The pattern coating composition contains (A) a compound having either an isocyanate group or a functional group that generates an isocyanate group by heating, and (b) a solvent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for forming a fine pattern using a specific pattern coating composition capable of forming a pattern insoluble or hardly soluble in a solvent or a developer, and a pattern coating composition used in this method.

  In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, lithography technology capable of microfabrication at a level of 0.10 μm or less is required. However, in the conventional lithography process, near-ultraviolet rays such as i-rays are generally used as radiation, and it is said that fine processing at a subquarter micron level is extremely difficult with this near-ultraviolet rays. Therefore, in order to enable microfabrication at a level of 0.10 μm or less, use of radiation having a shorter wavelength is being studied. Examples of such short-wavelength radiation include an emission line spectrum of a mercury lamp, far-ultraviolet rays typified by an excimer laser, an X-ray, an electron beam, and the like. ) Or ArF excimer laser (wavelength 193 nm) has been attracting attention.

  As a resist suitable for irradiation with such an excimer laser, a component having an acid dissociable functional group and a component that generates an acid upon irradiation with radiation (hereinafter also referred to as “exposure”) (hereinafter referred to as “acid generator”) Many resists using the chemical amplification effect (hereinafter also referred to as “chemically amplified resist”) have been proposed. As the chemically amplified resist, for example, a resist containing a resin having a tert-butyl ester group of carboxylic acid or a tert-butyl carbonate group of phenol and an acid generator has been proposed (see, for example, Patent Document 1). ). In this resist, the tert-butyl ester group or tert-butyl carbonate group present in the resin is dissociated by the action of an acid generated by exposure, and the resin has an acidic group composed of a carboxyl group or a phenolic hydroxyl group. As a result, the phenomenon that the exposed region of the resist film becomes readily soluble in an alkali developer is utilized.

  In such a lithography process, further fine pattern formation (for example, a fine resist pattern having a line width of about 45 nm) will be required in the future. In order to achieve such fine pattern formation of less than 45 nm, it is conceivable to shorten the light source wavelength of the exposure apparatus and increase the numerical aperture (NA) of the lens as described above. However, a new expensive exposure apparatus is required to shorten the light source wavelength. Further, when the lens has a high NA, the resolution and the depth of focus are in a trade-off relationship. Therefore, there is a problem that the depth of focus decreases even if the resolution is increased.

  Recently, as a lithography technique capable of solving such a problem, a method called an immersion exposure (liquid immersion lithography) method has been reported (for example, see Patent Document 2). In this method, at the time of exposure, a liquid high refractive index medium (immersion exposure liquid) such as pure water or a fluorine-based inert liquid having a predetermined thickness on at least the resist film between the lens and the resist film on the substrate. Is to intervene. In this method, a light source having the same exposure wavelength can be used by replacing the exposure optical path space, which has conventionally been an inert gas such as air or nitrogen, with a liquid having a higher refractive index (n), such as pure water. Similar to the case of using a light source with a shorter wavelength or the case of using a high NA lens, high resolution is achieved and there is no reduction in the depth of focus. If such immersion exposure is used, it is possible to realize the formation of a resist pattern that is low in cost, excellent in high resolution, and excellent in depth of focus, using a lens mounted on an existing apparatus. It has attracted a great deal of attention and is being put to practical use.

  However, it is said that the extension of the above-described exposure technique is limited to 45 nmhp, and technical development for the 32 nmhp generation that requires further fine processing is being carried out. In recent years, with the demand for higher complexity and higher density of such devices, a technique for patterning 32 nm LS by sparse line patterns such as double patterning or double exposure or by overlapping half-cycles of isolated trench patterns has been proposed. (For example, refer nonpatent literature 1).

  In one of the proposed examples, a 32 nm line with a 1: 3 pitch is formed and then processed by etching, and at a position shifted by a half cycle from the first resist pattern, the pitch is similarly 1: 3. A 32 nm line is formed and processed again by etching. As a result, a 32 nm line having a pitch of 1: 1 is finally formed. However, although there are proposals for several processes as described above, no proposals for more specific and practical methods and materials have been made yet.

Japanese Patent Laid-Open No. 5-232704 JP-A-10-303114 SPIE 2006 Vol. 6153 6153K

  The present invention has been made in view of such problems of the prior art, and the problem is that a pattern forming method capable of easily and efficiently forming a finer pattern, and this It is providing the pattern coating composition used for a pattern formation method.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have achieved the above-mentioned problems by coating a basic pattern with a specific composition containing a predetermined compound having an isocyanate group or the like. As a result, the present invention has been completed.

  That is, according to the present invention, the following pattern forming method and pattern coating composition are provided.

  [1] (1) formed on a substrate using a first radiation-sensitive resin composition containing (a) a resin that becomes alkali-soluble by the action of an acid, and (b) a radiation-sensitive acid generator. A step of applying a pattern coating composition on the surface of the first pattern to form a coating layer; and (2) a step of baking at least the coating layer to form a second pattern. The pattern formation method in which the said pattern coating composition contains an (A) compound which has at least any one of an isocyanate group and the functional group which produces | generates an isocyanate group by heating, and (B) solvent.

  [2] The pattern forming method according to [1], wherein the compound (A) has an aromatic skeleton.

  [3] The formation of the second pattern by repeating the formation of the coating layer in the step (1) and the baking treatment of the coating layer in the step (2) a plurality of times. ] The pattern formation method of description.

  [4] (3) A step of applying a second radiation-sensitive resin composition on the surface of the second pattern to form a resist layer, and (4) selectively exposing the resist layer, The pattern forming method according to any one of [1] to [3], further including a step of forming a third pattern by baking and developing.

  [5] It has at least one of an isocyanate group used in the step (2) of the pattern formation method according to any one of [1] to [4] and a functional group that generates an isocyanate group by heating (A A pattern coating composition containing a compound) and a solvent (B).

  [6] The pattern coating composition according to [5], wherein the compound (A) has an aromatic skeleton.

  [7] The pattern coating composition according to [5] or [6], wherein the solvent (B) is at least one selected from the group consisting of alcohols, ethers, hydrocarbons, and water.

  In the pattern forming method of the present invention, a specific pattern coating composition is applied and baked on a predetermined first pattern surface to form a first layer in which a layer insoluble or hardly soluble in a developer or a solvent is formed. Two patterns can be formed. For this reason, according to the pattern formation method of the present invention, it is possible to incorporate techniques such as the above-mentioned double patterning and double exposure, and a fine pattern can be easily and efficiently formed.

  The pattern coating composition of the present invention may be applied onto a predetermined first pattern surface and baked to form a second pattern having a layer insoluble or hardly soluble in a developer or a solvent. It can be done.

  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 embodiment, and is based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. It should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

1. Pattern coating composition:
The pattern coating composition used in the pattern forming method of the present invention contains (A) a compound having at least one of an isocyanate group and a functional group that generates an isocyanate group by heating, and (B) a solvent. It is. The details will be described below. The “pattern coating composition” in the present specification is a resist (pattern) patterned by exposure and development, and the coated pattern is insoluble in a developer or an organic solvent. Refers to a possible composition. Hereinafter, the “pattern coating composition” is also referred to as “coating agent”.

((A) Compound)
The compound (A) contained in the coating agent of the present invention has in its molecular structure at least one of an isocyanate group and a functional group that generates an isocyanate group by heating. (Hereinafter, also referred to as “(A1) low molecular weight compound”) and the like. At least one of the isocyanate group and the functional group that generates an isocyanate group by heating may be at least one in one molecule (A), but a plurality of functional groups may be present. In the case where the compound (A) is (A1) a low molecular compound, the hydrocarbon serving as a mother nucleus is a linear or branched hydrocarbon having 1 to 20 carbon atoms or an alicyclic having 3 to 20 carbon atoms. A formula hydrocarbon and an aromatic hydrocarbon having 6 to 20 carbon atoms are preferable, and an aromatic hydrocarbon having 6 to 20 carbon atoms is more preferable. The hydrocarbon may have a substituent.

  Preferable examples of the linear or branched hydrocarbon having 1 to 20 carbon atoms include methane, ethane, propane, butane, heptane, hexane, pentane, octane, nonane, decane, undecane, dodecane and the like. . Preferable examples of the alicyclic hydrocarbon having 3 to 20 carbon atoms include norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane and the like. Moreover, as a suitable example of C6-C20 aromatic hydrocarbon, benzene, naphthalene, anthracene, pyrene, biphenyl, etc. can be mentioned. In addition, when these hydrocarbons have a substituent, examples of suitable substituents include a hydroxyl group, a carboxyl group, a cyano group, a ketone group, and an ester group.

  (A1) Of the low molecular weight compounds, specific examples of those having an isocyanate group include butyl isocyanate, 1,4-butyl diisocyanate, cyclohexyl isocyanate, 1,4-cyclohexyl diisocyanate, phenyl isocyanate, m-phenylene diisocyanate, p-phenylene. Diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate and the like can be mentioned.

  Specific examples of (A1) low molecular weight compounds having a functional group that generates an isocyanate group by heating include compounds having a group in which isocyanate is capped with phenol, 2-[(3,5-dimethylpyrazolyl) ) Carboxyamino] ethyl methacrylate and the like. The 2-[(3,5-dimethylpyrazolyl) carboxyamino] ethyl methacrylate is a compound marketed by Showa Denko KK under the trade name “Karenz MOI-BP (registered trademark)”.

  The compound (A) is a polymer (hereinafter referred to as “repeating unit (1)”) containing a repeating unit having at least one of an isocyanate group and a functional group that generates an isocyanate group upon heating (hereinafter also referred to as “repeating unit (1)”). (A2) polymer ”).

  Preferable examples of the monomer capable of constituting the repeating unit having an isocyanate group include (meth) acrylic acid (2-ethyl isocyanate). Moreover, as a suitable example of the monomer which can comprise the repeating unit which has a functional group which produces | generates an isocyanate group by heating, 2-([1'-methylpropylideneamino] carboxyamino) ethyl methacrylate, 2- [ (3,5-dimethylpyrazolyl) carboxyamino] ethyl methacrylate and the like. In addition, 2-([1′-methylpropylideneamino] carboxyamino) ethyl methacrylate is a compound marketed by Showa Denko KK under the trade name “Karenz MOI-BM (registered trademark)”. Further, 2-[(3,5-dimethylpyrazolyl) carboxyamino] ethyl methacrylate is a compound marketed by Showa Denko KK under the trade name “Karenz MOI-BP (registered trademark)”.

  (A2) The polymer may contain at least one type of repeating unit (1), but may contain two or more types of repeating units (1). The polymer (A2) may contain a repeating unit other than the repeating unit (1) (hereinafter also referred to as “other repeating unit”).

  Specific examples of monomers that can constitute “other repeating units” include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylic acid, methacrylic acid, 2-hexahydrophthaloylethyl methacrylate, and p-hydroxystyrene. , Α-methyl-p-hydroxystyrene, p-acetoxystyrene, α-methyl-p-acetoxystyrene, p-benzyloxystyrene, p-tert-butoxystyrene, p-tert-butoxycarbonyloxystyrene, p-tert -Butyldimethylsiloxystyrene, diethyl maleate, diethyl fumarate, diethyl itaconate, phenyl (meth) acrylate, benzyl (meth) acrylate, styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, vinyl Ruene, p-methoxystyrene, pt-butoxystyrene, t-butyl (meth) acrylate, 4,4,4-trifluoro-3-hydroxy-1-methyl-3-trifluoromethyl-1-butyl (meta ) Acrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide and the like.

  (A2) The proportion of the repeating unit (1) contained in the polymer is preferably 10 mol% or more, more preferably 20 mol% or more, and more preferably 30 mol% or more in all repeating units. Is particularly preferred. (A2) When the ratio of the repeating unit (1) contained in the polymer is less than 10 mol%, the coating on the pattern may be insufficient, and the solvent resistance of the second pattern to be formed is insufficient. Tend to. The upper limit of the proportion of the repeating unit (1) contained in the polymer (A2) is not particularly limited, but may be 80 mol% or less.

  (A2) The polymer is, for example, a monomer or a mixture of monomers using a radical polymerization initiator such as hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds, etc. In the presence of a chain transfer agent in a suitable solvent. Examples of the solvent used for polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, norbornane. Cycloalkanes such as benzene, toluene, xylene, ethylbenzene, cumene and other aromatic hydrocarbons; chlorobutanes, bromohexanes, dichloroethanes, halogenated hydrocarbons such as hexamethylene dibromide, chlorobenzene; ethyl acetate, Saturated carboxylic acid esters such as n-butyl acetate, i-butyl acetate, methyl propionate, and propylene glycol monomethyl ether acetate; alkyl lactones such as γ-butyrolactone; and amines such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes, etc. Alkyls such as 2-butanone, 2-heptanone and methyl isobutyl ketone; cycloalkyl ketones such as cyclohexanone; 2-propanol, 1-butanol, 4-methyl-2-pentanol, propylene glycol monomethyl ether, etc. And the like. These solvents can be used alone or in combination of two or more.

  The reaction temperature in the polymerization is usually 40 to 120 ° C., preferably 50 to 100 ° C., and the reaction time is usually 1 to 48 hours, preferably 1 to 24 hours.

  (A2) The purity of the polymer is preferably high, and not only the content of impurities such as halogen and metal is low, but the residual monomer and oligomer components are below a predetermined value, for example, 0.1 mass by HPLC analysis. % Or less is preferable. When a coating containing a polymer (A2) having a high purity is used, the process stability can be improved and the pattern shape can be further refined. (A2) As a purification method of a polymer, the method shown below can be mentioned. As a method for removing impurities such as metals, a method in which a metal in a polymerization solution is adsorbed using a zeta potential filter, a metal is chelated and removed by washing the polymerization solution with an acidic aqueous solution such as oxalic acid or sulfonic acid. And the like. In addition, as a method of making the residual ratio of the monomer and oligomer components below the specified value, a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water washing and an appropriate solvent, a specific molecular weight or less Refining method to remove residual monomers by coagulating resin in poor solvent by dripping polymerization solution into poor solvent And a purification method in a solid state such as washing with a poor solvent for the resin slurry separated by filtration. Note that these methods may be combined.

  (A2) The polystyrene-converted weight average molecular weight (Mw) of the polymer measured by gel permeation chromatography (GPC) is usually 1,000 to 500,000, preferably 1,000 to 50,000, more preferably. 1,000 to 20,000. (A2) If the Mw of the polymer is too large, uniform application to the pattern surface tends to be difficult.

((B) solvent)
Although the kind of (B) solvent contained in the coating agent of this invention is not specifically limited, What is necessary is just a solvent which does not melt | dissolve a resist pattern easily or does not melt | dissolve. (B) Specific examples of the solvent include alcohols, ethers, hydrocarbons, water and the like.

  Specific examples of alcohols include 1-propanol, isopropanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3 -Methyl-1-butanol, 3-methyl-2-butanol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3 -Pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 1 -Heptanol, 2-heptanol, 2-methyl-2-heptanol, 2-methyl-3-heptanol, etc. .

  Specific examples of ethers include dipropyl ether, diisopropyl ether, butyl methyl ether, butyl ethyl ether, butyl propyl ether, dibutyl ether, diisobutyl ether, tert-butyl methyl ether, tert-butyl ethyl ether, tert-butyl propyl. Ether, di-tert-butyl ether, dipentyl ether, diisoamyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether, cyclopentyl ethyl ether, cyclohexyl ethyl ether, cyclopentyl propyl ether, cyclopentyl-2-propyl ether, cyclohexyl propyl ether, cyclohexyl-2- Propyl ether, cyclopentyl butyl ether, cyclopentyl-tert It can be mentioned ether, cyclohexyl ether, cyclohexyl -tert- butyl ether.

  Specific examples of hydrocarbons include nonane, decane, undecane, and the like. These solvents can be used singly or in combination of two or more.

(Pattern coating composition)
When the (A1) compound is contained in the pattern coating composition (coating agent) used in the pattern forming method of the present invention, the content ratio of this (A1) compound is (B) the entire coating agent including the solvent. On the other hand, it is preferably 0.5 to 50% by mass, more preferably 0.5 to 25% by mass, and particularly preferably 1 to 20% by mass. When the content ratio of the compound (A1) is less than 0.5% by mass, the developer resistance and solvent resistance of the second pattern to be formed tend not to be sufficiently exhibited. On the other hand, when the content ratio of the compound (A1) is more than 50% by mass, the present coating agent may not be uniformly applied on the pattern.

  On the other hand, when (A2) polymer is contained in the coating agent, the content ratio of this (A2) polymer is 0.5 to 50% by mass with respect to the entire coating agent including (B) the solvent. It is preferable that it is 0.5-25 mass%, and it is especially preferable that it is 1-20 mass%. When the content ratio of the polymer (A2) is less than 0.5% by mass, the developer resistance and solvent resistance of the second pattern to be formed tend not to be sufficiently expressed. On the other hand, when the content ratio of the polymer (A2) is more than 50% by mass, the present coating agent may not be uniformly applied on the pattern.

  In the case where both (A1) compound and (A2) polymer are contained in the coating agent, the total content ratio of these (A1) compound and (A2) polymer includes (B) solvent. It is preferable that it is 0.5-50 mass% with respect to the whole coating agent, It is more preferable that it is 0.5-25 mass%, It is especially preferable that it is 1-20 mass%. When the total content of the (A1) compound and the (A2) polymer is less than 0.5% by mass, the developer resistance and solvent resistance of the second pattern to be formed tend not to be sufficiently expressed. On the other hand, when the total content ratio of the (A1) compound and the (A2) polymer is more than 50% by mass, the present coating agent may not be uniformly applied on the pattern.

(Surfactant)
In the coating agent, a surfactant may be blended for the purpose of improving applicability, antifoaming property, leveling property and the like. Specific examples of surfactants that can be blended are as follows: BM-1000, BM-1100 (above, manufactured by BM Chemie); MegaFuck F142D, F172, F173, F183 (above, large) Nippon Ink Chemical Co., Ltd.); Fluorad FC-135, FC-170C, FC-430, FC-431 (above, manufactured by Sumitomo 3M); Surflon S-112, S-113, S-131, S-141, S-145 (made by Asahi Glass Co., Ltd.); SH-28PA, -190, -193, SZ-6032, SF-8428 (made by Toray Dow Corning Silicone); Emulgen A- Fluorosurfactants such as No. 60, No. 104P, and No. 306P (above, manufactured by Kao Corporation) can be given. In addition, the compounding quantity of these surfactant is (A1) compound or (A2) polymer (when all of (A1) compound and (A2) polymer are contained, these are total) 100 mass Preferably it is 5 mass parts or less with respect to a part.

2. Pattern formation method:
((1) Process)
In the step (1), the above-mentioned pattern coating composition (coating agent) according to the present invention is applied on the surface of the first pattern formed on the substrate to form a coating layer. In order to form the first pattern on the substrate, first, on a substrate such as a silicon wafer or a wafer coated with SiN or an organic antireflection film, appropriate coating such as spin coating, casting coating, roll coating, etc. A first radiation-sensitive resin composition (first resist agent) is applied by an application means to form a first resist layer. The first resist agent contains (a) a resin that becomes alkali-soluble by the action of an acid, and (b) a radiation-sensitive acid generator. In addition, after apply | coating a 1st resist agent, you may volatilize the solvent in a coating film by prebaking (PB) as needed. Although the prebaking heating conditions are appropriately selected depending on the composition of the first resist agent, they are usually 30 to 200 ° C, preferably 50 to 150 ° C.

  In order to maximize the potential of the first resist agent, an organic or inorganic antireflection film is formed on the substrate as disclosed in, for example, Japanese Patent Publication No. 6-12458. It ’s good to leave. In order to prevent the influence of basic impurities contained in the environmental atmosphere, it is also preferable to provide a protective film on the first resist layer as disclosed in, for example, JP-A-5-188598. . It is also preferable to perform both formation of the antireflection film and formation of the protective film.

  The required region of the formed first resist layer is exposed by irradiating with radiation through a mask having a predetermined pattern to form a pattern latent image portion (portion that has become insoluble in alkali by exposure). The radiation used is appropriately selected from visible rays, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams, etc., depending on the type of (b) radiation-sensitive acid generator contained in the first resist agent. However, far ultraviolet rays typified by ArF excimer laser (wavelength 193 nm), KrF excimer laser (wavelength 248 nm) and the like are preferable, and ArF excimer laser (wavelength 193 nm) is particularly preferable. In addition, exposure conditions, such as exposure amount, are suitably selected according to the compounding composition of a 1st resist agent, the kind of additive, etc. Furthermore, it is preferable to perform heat treatment (PEB) after exposure. By this PEB, (a) the dissociation reaction of the acid dissociable group in the resin can be smoothly advanced. The heating condition of PEB is appropriately selected depending on the composition of the first resist agent, but is usually 30 to 200 ° C, preferably 50 to 170 ° C.

  By developing the exposed first resist layer, the pattern latent image portion is exposed, and a positive first pattern having a predetermined space portion is formed on the substrate. Examples of the developer that can be 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, 1,5-diazabicyclo- An alkaline aqueous solution in which at least one of alkaline compounds such as [4.3.0] -5-nonene is dissolved is preferable. The concentration of the alkaline aqueous solution is usually 10% by mass or less. When the concentration of the alkaline aqueous solution exceeds 10% by mass, the non-exposed portion tends to be easily dissolved in the developer. In addition, after developing using alkaline aqueous solution, generally it wash | cleans with water and dries.

  An organic solvent can also be added to the alkaline aqueous solution (developer). Examples of the organic solvent that can be added 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 alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, 1,4-hexanedimethylol, and the like; tetrahydrofuran, dioxane Ethers such as ethyl acetate, n-butyl acetate, i-amyl acetate, aromatic hydrocarbons such as toluene and xylene, phenol, acetonylacetone, dimethylformamide, etc. That. These organic solvents can be used individually by 1 type or in combination of 2 or more types.

  The addition amount of the organic solvent is preferably 100 parts by volume or less with respect to 100 parts by volume of the alkaline aqueous solution. When the addition amount of the organic solvent is more than 100 parts by volume with respect to 100 parts by volume of the alkaline aqueous solution, the developability may be deteriorated and the development residue in the exposed part may increase. An appropriate amount of a surfactant or the like can be added to the developer.

  On the surface of the first pattern formed on the substrate, the aforementioned coating agent is applied so as to cover the first resist pattern to form a coating layer. Although the method for applying the coating agent is not particularly limited, an appropriate application means such as spin coating, cast coating, roll coating or the like can be employed.

((2) Process)
In the step (2), the coating layer formed on the surface of at least the first pattern is baked (heated). By this baking treatment, a second pattern having developer resistance and solvent resistance can be formed by the coating layer formed on the surface of the first pattern. The heating conditions for the baking treatment are appropriately selected depending on the composition of the coating agent, but are usually 30 to 200 ° C, preferably 50 to 170 ° C.

  The second pattern formed as described above is insoluble or hardly soluble in the developer or solvent. Therefore, even if the second radiation-sensitive resin composition (second resist agent) is applied to the formed second pattern, exposed, and developed, the pattern width depends on the thickness of the applied coating agent, etc. However, the pattern shape generally remains.

  It is preferable to repeat the steps (1) and (2) a plurality of times, that is, to form the second pattern by repeating the formation of the coating layer by applying the coating agent and the baking treatment a plurality of times. Note that if the number of repetitions is excessively increased, the process may be lengthened and the practicality may be impaired. Therefore, the number of repetitions is preferably 2 to 10 times.

  It is preferable that the baked coating layer is washed as necessary. Examples of the medium that can be used for washing include water, the above-described developer, and the solvent (B) contained in the above-described coating agent.

  In addition, a second resist agent is applied on the surface of the second pattern formed in the step (2) to form a resist layer, and then the resist layer is selectively exposed, and then baked and developed. By performing so-called double patterning, a third pattern can be additionally formed on the second pattern. If the third pattern thus formed is used, a semiconductor can be manufactured. Hereinafter, the double patterning process will be described.

((3) Process)
(3) In the step, the second resist agent is applied on the surface of the second pattern by an appropriate application means such as spin coating, cast coating, roll coating or the like. Thereby, the 2nd resist layer which consists of a 2nd resist agent can be formed on a 2nd pattern. Thereafter, as in the case of step (1), pre-baking (PB) may be performed as necessary.

((4) Process)
In the step (4), first, the formed second resist layer is selectively exposed in the same manner as in the step (1). More specifically, the second resist layer and, if necessary, the space portion of the second pattern are selectively exposed through a mask. Next, after performing baking (PEB), development is performed in the same manner as in the step (1), whereby a positive third pattern can be formed.

(Positive resist agent)
In the first resist agent and the second resist agent described above, the acid dissociable groups contained in each of the first resist agent and the second resist agent are dissociated by the action of the acid generated from the radiation-sensitive acid generator by exposure, and dissolved in an alkali developer. The exposed portion of the resist having improved properties is dissolved and removed by an alkali developer, and a positive resist pattern can be obtained.

  Either or both of the first resist agent and the second resist agent contain a resin having a repeating unit represented by the following general formula (1) (hereinafter also referred to as “resist agent resin”). It is preferable.

In the general formula (1), R ¹ represents hydrogen or a methyl group, and a plurality of R ² are independently of each other a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, Or a C1-C4 linear or branched alkyl group is shown. (I) at least one of R ² is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof; or (ii) any two R ² are bonded to each other. And a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof containing carbon atoms to which each is bonded, and the remaining R ² is a straight chain having 1 to 4 carbon atoms Alternatively, it is a branched alkyl group, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof.

In the general formula (1), a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ² carbon atoms and any two of R ² is formed by bonding to each other, 4-20 Specific examples of the divalent alicyclic hydrocarbon group include fatty acids derived from cycloalkanes such as norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane. A group consisting of a cyclic ring; a group consisting of these alicyclic rings is, for example, a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methyl Examples include a group substituted with one or more linear, branched, or cyclic alkyl groups having 1 to 4 carbon atoms such as a propyl group and a t-butyl group. Of these, a group consisting of an alicyclic ring derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane, or cyclohexane, or a group obtained by substituting these with the above alkyl group is preferable.

In the general formula (1), specific examples of the derivative of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ² include a hydroxyl group; a carboxyl group; an oxo group (that is, a ═O group). ); Hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3- A hydroxyalkyl group having 1 to 4 carbon atoms such as hydroxybutyl group and 4-hydroxybutyl group; methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1- C1-C4 alkoxyl groups such as methylpropoxy group and t-butoxy group; cyano group; cyanomethyl group, 2-cyanoethyl group, 3-cyanopropyl group The group which has 1 or more types of substituents, such as C2-C5 cyanoalkyl groups, such as a propyl group and 4-cyanobutyl group, can be mentioned. Of these, a hydroxyl group, a carboxyl group, a hydroxymethyl group, a cyano group, and a cyanomethyl group are preferable.

In the general formula (1), specific examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R ² include a methyl group, an ethyl group, an n-propyl group, and i-propyl. Group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like. Of these, a methyl group and an ethyl group are preferable.

In the general formula (1), specific examples of the group represented by “—C (R ² ) ₃ ” include groups represented by the following (general) formulas (1a) to (1f). .

In the general formulas (1a) to (1c), (1e) and (1f), R ³ is independently a linear or branched alkyl group having 1 to 4 carbon atoms, and m is 0 or 1. Specific examples of the linear or branched alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1- Examples thereof include a methylpropyl group and a t-butyl group. Of these, a methyl group and an ethyl group are preferable.

In the general formula (1), a portion represented by “—COOC (R ² ) ₃ ” is a portion that is dissociated by the action of an acid to form a carboxyl group and becomes an alkali-soluble portion. This “alkali-soluble site” is a group that becomes an anion (alkali-soluble) by the action of an alkali. On the other hand, an “acid-dissociable group” is a group in which an alkali-soluble site is protected with a protecting group, and is a group that is not “alkali-soluble” until the protecting group is removed with an acid.

  The resist agent resin itself is a resin that is insoluble in alkali or hardly soluble in alkali, but is resin that becomes alkali-soluble by the action of an acid. Here, “alkali insoluble or hardly soluble in alkali” means development conditions for forming a resist pattern using a resist layer comprising a resist agent containing a resin having a repeating unit represented by the general formula (1). In the case where a film made of only the resin containing the repeating unit represented by the general formula (1) is processed (but not exposed), 50% or more of the initial film thickness remains after the processing. Refers to nature. On the other hand, “alkali-soluble” refers to a property in which 50% or more of the initial film thickness of the film is lost after the same treatment.

  The polystyrene-reduced weight average molecular weight Mw measured by gel permeation chromatography (GPC) of the resist agent resin is usually 1,000 to 500,000, preferably 1,000 to 100,000, and more preferably 1,000. ~ 50,000. When Mw is less than 1,000, the heat resistance of the resist pattern to be formed tends to decrease. On the other hand, if the Mw exceeds 500,000, the developability tends to be lowered. Moreover, it is preferable that ratio (Mw / Mn) of Mw of resin for resist agents and the polystyrene conversion number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 1-5, More preferably. In addition, it is preferable that the ratio of the low molecular weight component which has a monomer as a main component contained in resin for resist agents is 0.1 mass% or less in conversion of solid content with respect to the whole resin. The content ratio of the low molecular weight component can be measured, for example, by high performance liquid chromatography (HPLC).

(Method for producing resin for resist agent)
Resist agent resin is a radical polymerization of a monomer component containing a polymerizable unsaturated monomer corresponding to a desired repeating unit, such as hydroperoxides, dialkyl peroxides, diacyl peroxides, and azo compounds. It can manufacture by using an initiator and superposing | polymerizing in a suitable solvent in presence of a chain transfer agent as needed.

  Examples of the solvent used for polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, norbornane. Cycloalkanes such as benzene, toluene, xylene, ethylbenzene, cumene and other aromatic hydrocarbons; chlorobutanes, bromohexanes, dichloroethanes, halogenated hydrocarbons such as hexamethylene dibromide, chlorobenzene; ethyl acetate, Saturated carboxylic acid esters such as n-butyl acetate, i-butyl acetate and methyl propionate; ethers such as tetrahydrofuran, dimethoxyethanes and diethoxyethane; methanol, ethanol, 1-propanol, 2-propanol, 1- Butanol, 2-pig Alcohol, isobutanol, 1-pentanol, 3-pentanol, 4-methyl-2-pentanol, o-chlorophenol, 2- (1-methylpropyl) phenol, etc .; acetone, 2-butanone, Mention may be made of ketones such as 3-methyl-2-butanone, 4-methyl-2-pentanone, 2-heptanone, cyclopentanone, cyclohexanone and methylcyclohexanone. These solvents can be used alone or in combination of two or more.

  Moreover, the reaction temperature in said superposition | polymerization is 40-150 degreeC normally, Preferably it is 50-120 degreeC, and reaction time is 1-48 hours normally, Preferably it is 1-24 hours. In addition, the resin for a resist agent to be obtained is preferable as the content of impurities such as halogen and metal is smaller because sensitivity, resolution, process stability, pattern profile and the like can be further improved. Examples of resist resin purification methods include chemical purification methods such as water washing and liquid-liquid extraction, and combinations of these chemical purification methods and physical purification methods such as ultrafiltration and centrifugation, etc. Can be mentioned.

(Radiosensitive acid generator)
The positive resist agent contains a radiation-sensitive acid generator (hereinafter also simply referred to as “acid generator”) that is decomposed by exposure. Specific examples of the acid generator include various substances (compounds) shown below.

  Triphenylsulfonium trifluoromethanesulfonate, tri-tert-butylphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium trifluoromethanesulfonate, 1- (3,5-dimethyl- 4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium trifluoromethanesulfonate, triphenylsulfonium perfluoro-n-butanesulfonate, tri-tert-butylphenylsulfonium per Fluoro-n-butanesulfonate, 4-cyclohexylphenyl-diph Nylsulfonium perfluoro-n-butanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium perfluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-butane Sulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro-n-butanesulfonate, and the like.

  Triphenylsulfonium perfluoro-n-octane sulfonate, tri-tert-butylphenylsulfonium perfluoro-n-octane sulfonate, 4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-octane sulfonate, 4-methanesulfonylphenyl-diphenylsulfonium per Fluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro- n-octanesulfonate, triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2′-yl) -1,1,2,2-tetrafluoroethanesulfonate, -Tert-butylphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [ 2.2.1] Hepta-2′-yl) -1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2 ′ -Yl) -1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2 ' -Yl) -1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothioff Iodonium 2- (bicyclo [2.2.1] hept-2'-yl) 1,1,2,2-tetrafluoroethane sulfonate and the like.

  Triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- (bicyclo [2.2.1] hepta-2 '-Yl) -1,1-difluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 4-methanesulfonylphenyl -Diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- ( Bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroeta Sulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium Nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n Octane sulfonate, bis (4-t- butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate like.

  Trifluoromethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide Perfluoro-n-octanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, 2-bicyclo [2.2.1] hept-2-yl-1,1,2 , 2-tetrafluoroethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, N- (trifluoromethanesulfonyloxy) succinimide, N- (nonafluoro-n-butanesulfonyloxy) succinimide N- (perfluoro-n-octanesulfonyloxy) succinimide, N- (2-bicyclo [2.2 1] hept-2-yl-1,1,2,2-tetrafluoroethane sulfonyloxy) succinimide, 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate and the like.

  Compounds represented by the following formulas (B1-1) to (B1-8).

  These acid generators can be used singly or in combination of two or more.

  The ratio of the acid generator contained in the positive resist agent is 100 parts by weight of the resist agent resin from the viewpoint of resist sensitivity and developability, and suppression of elution into the immersion liquid when performing immersion exposure. The amount is usually 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass. When the content ratio of the acid generator is less than 0.1 parts by mass, sensitivity and developability tend to be lowered. On the other hand, if it exceeds 20 parts by mass, the transparency to radiation is lowered, it becomes difficult to obtain a rectangular resist pattern, and the elution suppressing effect tends to be lost.

(Other additives)
In addition to the resist resin and the acid generator, the positive resist agent preferably contains one or more additives (other additives). As an example of the other additive which can be contained, a nitrogen-containing compound can be mentioned.

  Specific examples of the nitrogen-containing compound include tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, cyclohexyldimethylamine, and dicyclohexylmethylamine. , Tri (cyclo) alkylamines such as tricyclohexylamine; aromatic amines such as N-methylaniline, N, N-dimethylaniline and 2,6-diisopropylaniline; triethanolamine, N, N-di (hydroxy Alkanolamines such as ethyl) aniline; N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-Aminophenyl) -1-methylethyl] benzenetetramethyle Diamine, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether;

  Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt-butoxycarbonyldicyclohexylamine, Nt- Butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, (S)-(−)-1- (t-butoxy Carbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonylpiperazine, N, N-di-t-butoxy Rubonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′-diaminodiphenylmethane, N, N′-di-t -Butoxycarbonylhexamethylenediamine, N, N, N'N'-tetra-t-butoxycarbonylhexamethylenediamine, N, N'-di-t-butoxycarbonyl-1,7-diaminoheptane, N, N'- Di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10-diaminodecane N, N′-di-t-butoxycarbonyl-1,12-diaminododecane, N, N′-di-t-butoxycarbonyl-4, N-t-butoxycarbonyl group-containing amino such as' -diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole Compound;

  Pyridines such as 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine, nicotinamide; piperazines such as piperazine and 1- (2-hydroxyethyl) piperazine, purines, 3-piperidino -1,2-propanediol, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, benzimidazole, 2-phenylbenzimidazole, Nt-butoxycarbonylbenz Examples thereof include imidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole, and the like. In addition, the said nitrogen containing compound can be used individually by 1 type or in combination of 2 or more types.

  The content of the nitrogen-containing compound is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, with respect to 100 parts by mass of the resist resin. There exists a possibility that the sensitivity of the resist layer formed may fall remarkably that the compounding quantity of a nitrogen-containing compound exceeds 10 mass parts.

  Examples of other additives other than the nitrogen-containing compound include various additives such as an alicyclic additive having an acid dissociable group, a surfactant, and a sensitizer.

  The alicyclic additive having an acid dissociable group is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. Examples of such alicyclic additives include 1-adamantanecarboxylic acid, 2-adamantanone, 1-adamantanecarboxylic acid t-butyl, 1-adamantanecarboxylic acid t-butoxycarbonylmethyl, 1-adamantanecarboxylic acid α. -Butyrolactone ester, 1,3-adamantane dicarboxylic acid di-t-butyl, 1-adamantane acetate t-butyl, 1-adamantane acetate t-butoxycarbonylmethyl, 1,3-adamantane diacetate di-t-butyl, 2, Adamantane derivatives such as 5-dimethyl-2,5-di (adamantylcarbonyloxy) hexane;

Deoxycholate t-butyl, deoxycholate t-butoxycarbonylmethyl, deoxycholate 2-ethoxyethyl, deoxycholate 2-cyclohexyloxyethyl, deoxycholate 3-oxocyclohexyl, deoxycholate tetrahydropyranyl, deoxychol Deoxycholic acid esters such as acid mevalonolactone ester; tert-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid, 2-cyclohexyloxyethyl lithocholic acid, 3-oxocyclohexyl lithocholic acid, lithocol Lithocholic acid esters such as tetrahydropyranyl acid, lithocholic acid mevalonolactone ester; dimethyl adipate, diethyl adipate, dipropyl adipate, di-n-adipate Chill, other alkyl carboxylic acid esters such as adipate t- butyl, 3- [2-hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] dodecane and the like. These alicyclic additives can be used singly or in combination of two or more.

  The surfactant is a component having an action of improving coatability, striation, developability and the like. Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, and polyethylene glycol dilaurate. In addition to nonionic surfactants such as polyethylene glycol distearate, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (manufactured by Tochem Products), Megafax F171, F173 (manufactured by Dainippon Ink and Chemicals), Florard FC430, FC431 (Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (made by Asahi Glass Co., Ltd.), etc. Can do. In addition, these surfactant can be used individually by 1 type or in combination of 2 or more types.

  The above sensitizer absorbs radiation energy and transmits the absorbed energy to the acid generator, thereby increasing the amount of acid generated, improving the apparent sensitivity of the positive resist agent. It is a component which has the effect to make. Examples of such sensitizers include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines, and the like. In addition, these sensitizers can be used individually by 1 type or in combination of 2 or more types.

  In addition to the above-mentioned additives other than those described above, by adding a dye or a pigment to the positive resist agent, the latent image of the exposed portion can be visualized and the influence of halation during exposure can be reduced. Moreover, the adhesiveness with a board | substrate can be improved by mix | blending an adhesion assistant with a positive resist agent. Furthermore, an alkali-soluble resin, a low-molecular alkali solubility control agent having an acid-dissociable protecting group, an antihalation agent, a storage stabilizer, an antifoaming agent, and the like can be blended.

(solvent)
A positive resist agent usually contains a solvent. Specific examples of the solvent include 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, 4-methyl-2-pentanone, 3-methyl-2-pentanone, 3,3-dimethyl-2 -Linear or branched ketones such as butanone, 2-heptanone, 2-octanone; cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, isophorone, etc. Cyclic ketones; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-i-propyl ether acetate, propylene glycol mono-n-butyl ether acetate Propylene glycol monoalkyl ether acetates such as propylene glycol mono-i-butyl ether acetate, propylene glycol mono-sec-butyl ether acetate, propylene glycol mono-t-butyl ether acetate; methyl 2-hydroxypropionate, 2-hydroxypropionic acid Ethyl, 2-hydroxypropionate n-propyl, 2-hydroxypropionate i-propyl, 2-hydroxypropionate n-butyl, 2-hydroxypropionate i-butyl, 2-hydroxypropionate sec-butyl, 2-hydroxy Alkyl 2-hydroxypropionates such as t-butyl propionate; methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid Chill, other 3-alkoxy propionic acid alkyl such as ethyl 3-ethoxypropionate,

  Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, 2-hydroxy-2-methyl Ethyl propionate, ethoxy Ethyl acetate, hydroxyethyl acetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, 3-methyl-3 -Methoxybutyl butyrate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate, ethyl pyruvate, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether And γ-butyrolactone.

  Among these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, γ-butyrolactone and the like are preferable. . These solvents can be used singly or in combination of two or more.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified.

(Reference Example 1: Fabrication of substrate)
2-Methyl-adamantyl methacrylate (60 mol%) and 4-oxa-5-oxo-2-tricyclo [4.2.1.0 ^3,7 ] nonan-2-yl methacrylate synthesized by radical polymerization 100 parts of (40 mol%) copolymer and 0.43 part of nonafluoro-n-butanesulfonic acid were mixed with 650 parts of cyclohexanone and dissolved, and then filtered through a membrane filter having a pore diameter of 0.45 μm. A resin solution was prepared. The prepared resin solution was spin-coated on a silicon wafer using a trade name “CLEAN TRACK ACT8” (manufactured by Tokyo Electron), and then baked at 110 ° C. for 60 seconds to prepare a substrate (A).

(Reference Example 2: Preparation of coating agent)
A coating agent was prepared by mixing 10 parts of m-xylylene diisocyanate and 90 parts of di-n-butyl ether.

(Example 1: Coating treatment (1))
The prepared coating agent (Reference Example 1) was liquid deposited (applied) on the surface of the substrate (A) so as to cover the entire surface, and allowed to stand for 10 seconds. The coating agent was removed from the substrate by blowing off with a nitrogen gun, and then baked at 150 ° C. for 60 seconds using a hot plate to prepare a treated substrate (1).

(Example 2: Coating treatment (2))
The process substrate (2) was produced by repeating the process implemented by the above-mentioned "coating process (1)" 5 times.

[Developer resistance]: Using a Pasteur pipette, tetra n-butylammonium produced by JSR on the surface of each substrate (substrate (A), treated substrate (1), and treated substrate (2)). A developer (trade name “PD523”), which is a 2.38 mass% aqueous solution of hydroxide, was added dropwise (spotted), allowed to stand for 30 seconds, and then washed with distilled water. The state of the spotted spot was visually observed, and “developer resistance” was evaluated according to the following criteria.
X: The surface layer dissolved until it reached the silicon wafer.
○: Although dissolution of the surface layer could be confirmed, it did not reach the silicon wafer.
A: Dissolution of the surface layer could not be confirmed or could not be confirmed easily.

[Solvent resistance]: Using a Pasteur pipette, liquid drops of propylene glycol monomethyl ether acetate are dropped on the surface of each substrate (substrate (A), treated substrate (1), and treated substrate (2)). (Spotting). After standing for 30 seconds, spotted propylene glycol monomethyl ether acetate was removed from the substrate by blowing off with a nitrogen gun. The state of the spotted spot was visually observed, and “solvent resistance” was evaluated according to the following criteria.
X: The surface layer dissolved until it reached the silicon wafer.
○: Although dissolution of the surface layer could be confirmed, it did not reach the silicon wafer.
A: Dissolution of the surface layer could not be confirmed or could not be confirmed easily.

  By processing a specific pattern coating composition on the pattern, developer resistance and solvent resistance can be imparted, so that it is expected that pattern formation can be performed again on the pattern. Therefore, the pattern forming method of the present invention can be suitably used for double patterning processing carried out in the field of microfabrication represented by the manufacture of integrated circuit elements that are expected to be further miniaturized in the future.

Claims (7)

(1) A first radiation-sensitive resin composition containing (a) a resin that becomes alkali-soluble by the action of an acid, and (b) a first radiation-sensitive resin composition containing a radiation-sensitive acid generator. Applying a pattern coating composition on the surface of the pattern to form a coating layer;
(2) at least the step of baking the coating layer to form a second pattern,
The pattern formation method in which the said pattern coating composition contains (A) compound which has at least any one of an isocyanate group and the functional group which produces | generates an isocyanate group by heating, and (B) solvent.   The pattern forming method according to claim 1, wherein the compound (A) has an aromatic skeleton.   The pattern formation according to claim 1 or 2, wherein the formation of the coating layer in the step (1) and the baking treatment of the coating layer in the step (2) are repeated a plurality of times to form the second pattern. Method. (3) applying a second radiation-sensitive resin composition on the surface of the second pattern to form a resist layer;
(4) after selectively exposing the resist layer, baking and developing to form a third pattern;
The pattern formation method according to claim 1, further comprising: It is used in the step (2) of the pattern forming method according to any one of claims 1 to 4.
A pattern coating composition comprising (A) a compound having at least one of an isocyanate group and a functional group that generates an isocyanate group by heating, and (B) a solvent.   The pattern coating composition according to claim 5, wherein the compound (A) has an aromatic skeleton.   The pattern coating composition according to claim 5 or 6, wherein the solvent (B) is at least one selected from the group consisting of alcohols, ethers, hydrocarbons, and water.