JP5270839B2 - COATING FORMING AGENT FOR PATTERN REFINEMENT AND METHOD FOR FORMING FINE PATTERN USING THE - Google Patents

Abstract

This invention provides a coating forming agent for pattern fining, which does not cause any defect after fining treatment, can suppress and control a variation in the level of fining even in fining treatment of an ultrafine resist pattern, particularly having a size of not more than 120 nm with an enhanced aspect ratio, can maintain a good resist pattern shape after the fining treatment while maintaining the desired fining level, and, at the same time, can eliminate troubles caused by the occurrence of bacteria and the like within a wafer plane after the coating of a coating forming agent for pattern fining, and a method for fine pattern formation using the coating forming agent. The coating forming agent for pattern fining is a coating forming agent for use in the formation of a fine pattern covered on a substrate having a photoresist pattern and is characterized by comprising (a) a water soluble polymer and (b) at least one compound selected from carboxyl-containing compounds or their salts or esterification products, peroxides, and peracids.

Description

  The present invention relates to a coating forming agent for pattern miniaturization in the field of photolithography and a method for forming a fine pattern using the same. More specifically, the present invention relates to a coating forming agent for pattern miniaturization that can cope with high integration and miniaturization of semiconductor devices in recent years, and a micropattern forming method using the same.

  In the manufacture of electronic components such as semiconductor devices and liquid crystal devices, a photolithography technique is used when processing such as etching is performed on a substrate. In this photolithography technique, a coating (photoresist layer) is provided on a substrate using a so-called photoresist material that is sensitive to actinic radiation, then this is selectively irradiated with actinic radiation, exposed, and developed. The photoresist layer is selectively dissolved and removed to form an image pattern (photoresist pattern) on the substrate. Then, an etching process is performed using this photoresist pattern as a protective layer (mask pattern) to form a wiring pattern on the substrate.

  In recent years, the trend toward higher integration and miniaturization of semiconductor devices has increased, and the formation of these photoresist patterns has progressed, and ultrafine processing with a pattern width of 120 nm or less is currently required. In addition, actinic rays used for forming a photoresist pattern are also irradiated with short-wavelength light such as KrF, ArF excimer laser light, EB, EUV, and soft X-rays. Research and development of material systems with physical properties corresponding to irradiation light are being conducted.

  In addition to countermeasures for ultra-miniaturization due to such improvements in photoresist materials, research and development of pattern miniaturization techniques that exceed the resolution limits of photoresist materials are also being conducted from the aspect of pattern formation methods.

  For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 5-166717), after a pattern is formed on a pattern forming resist applied on a substrate, a mixing generation resist that is mixed with the pattern forming resist is applied to the entire surface of the substrate. Then, baking is performed to form a mixing layer on the side wall to the surface of the resist for pattern formation, and a non-mixing portion of the resist for generating the mixing is removed to form a pattern that is miniaturized by the size of the mixing layer. A method is disclosed. In Patent Document 2 (Japanese Patent Application Laid-Open No. 5-241348), a resist containing a resin that is insolubilized in the presence of an acid is deposited on a substrate on which a resist pattern containing an acid generator is formed, and then heat treatment is performed. Then, after the acid is diffused from the resist pattern to form a resist film having a constant thickness near the interface of the resist pattern, development is performed to remove the resin portion where the acid is not diffused, thereby removing the constant thickness. A pattern forming method in which the size is reduced is disclosed. Further, in Patent Document 3 (Japanese Patent Application Laid-Open No. 10-073927), a resist pattern containing an acid generator is covered with a material containing a material that crosslinks in the presence of an acid, and the resist pattern is formed by subsequent heating or exposure treatment. A method for reducing the hole diameter and separation width of a resist pattern by generating an acid, forming a crosslinked layer formed at the interface as a coating layer of the resist pattern, and thickening the resist pattern is disclosed.

  However, in these methods, the thermal dependence in the wafer surface is as large as about 10 nm / ° C., and the film thickness of the coating film formed on the resist pattern can be uniformly controlled in the wafer surface having a large diameter. Therefore, there is a problem that the variation of the resist pattern dimension after the miniaturization process is noticeable. In addition, it is difficult to suppress the occurrence of defects (pattern defects) after miniaturization processing, and it is also difficult to perform rework processing (processing to remove the resist pattern itself from the wafer once) when re-forming the resist pattern. There is a problem that there is.

  On the other hand, a method is also known in which a resist pattern is fluidized by heat treatment or the like to reduce the pattern dimensions. For example, Patent Document 4 (Japanese Laid-Open Patent Publication No. 1-307228) discloses a method of forming a fine pattern by forming a resist pattern on a substrate and then performing heat treatment to deform the cross-sectional shape of the resist pattern. It is disclosed. In Patent Document 5 (Japanese Patent Laid-Open No. 4-340221), after forming a resist pattern, it is heated before and after the softening temperature, and the pattern dimension is changed by fluidizing the resist to form a fine pattern. A method is disclosed.

  However, in these methods, it is difficult to control the amount of miniaturization by thermal flow, it is difficult to obtain a resist pattern that maintains a good rectangular shape after the miniaturization process, and the dense pattern mixed in the wafer surface There is a problem that it is difficult to control the amount of micronization to be constant.

  As a method obtained by further developing the above method, for example, in Patent Document 6 (Japanese Patent Laid-Open No. 7-45510), a resin for preventing excessive flow of a resist pattern on a substrate in which a resist pattern is formed on the substrate. A method is disclosed in which a film is formed, followed by heat treatment, the resist is fluidized to change the pattern dimensions, and then the resin is removed to form a finer resist pattern.

  However, with this method, it is difficult to obtain a resist pattern that maintains a good rectangular shape after the miniaturization process, and it is difficult to control the miniaturization amount of the dense pattern mixed in the wafer surface uniformly. Furthermore, there is a problem that it is difficult to suppress the variation in the fineness of the photoresist pattern with respect to the variation in the heating temperature.

  Furthermore, the present applicants have disclosed Patent Documents 7 to 12 (JP 2003-084459 A, JP 2003-084460 A, JP 2003-107752 A, JP 2003-142381 A, JP 2003-195527 A). (Patent Publication No. JP-A-2003-202679) and the like have proposed a technique relating to a pattern forming coating forming agent and a method for forming a fine pattern. With the techniques shown in Patent Documents 7 to 12 and the like, a fine pattern having required characteristics in a semiconductor device, such as improving the controllability of pattern dimensions and making the resist pattern after the miniaturization process into a good rectangular shape, etc. Became possible.

  In the fine pattern formation technique using these pattern refinement coating forming agents, first, a photoresist layer is provided on a substrate, and this is exposed and developed to form a photoresist pattern. Next, the entire surface of the substrate is coated with a pattern-miniaturizing coating-forming agent, and then heated to make the photoresist pattern wider by utilizing the heat shrinking action of the pattern-miniaturizing coating-forming agent. As a result, the photoresist pattern interval is narrowed, the pattern width defined by the photoresist pattern interval is also narrowed, and a miniaturized pattern is obtained.

  That is, the pattern miniaturization is affected by resist pattern dimension control in two stages, that is, a photoresist pattern formation stage (first stage) and a thermal shrinkage stage (second stage) of the pattern miniaturization coating forming agent. In forming a resist pattern using such a technique, the resist pattern shape formed in the first stage can be shrunk at a uniform heat shrinkage rate while maintaining the shape in the second stage heat shrinking process. is necessary.

  However, in the ultra-miniaturization of the order of pattern size of 120 nm or less and the miniaturization process of the resist pattern with a high aspect ratio, the resist pattern shape after the miniaturization process is more strictly controlled, and the miniaturization amount is more exacting. Under these circumstances, the top and bottom portions of the resist pattern are formed after the miniaturization process even when using the fine pattern formation technology using these coating forming agents for pattern miniaturization. Deterioration of the shape such as rounding of the shape of the wafer slightly occurs, problems such as fluctuations in the amount of miniaturization due to fluctuations in the heating temperature within the wafer surface, and the density that is mixed in the wafer surface Problems such as variations in the amount of pattern miniaturization occur, and it is difficult to strictly control these in the nanometer order. There is. It is necessary to eliminate these problems while maintaining the desired amount of miniaturization, and furthermore, defects due to the occurrence of bacteria etc. in the wafer surface after applying such a coating forming agent for pattern miniaturization Need to be resolved. The present invention is for solving this problem.

In Patent Document 13 (Japanese Patent Laid-Open No. 2001-281886), an acid film made of a resist pattern reducing material containing a water-soluble resin is coated on the resist pattern surface, and then the resist pattern surface layer is converted to alkali-soluble. Then, a method of reducing the resist pattern by removing the surface layer and the acidic film with an alkaline solution is disclosed, and Patent Document 14 (Japanese Patent Laid-Open No. 2002-184673) discloses a resist pattern on a substrate. And forming a coating film containing a water-soluble film-forming component on the resist pattern, heat-treating the resist pattern and the coating film, and then immersing them in an aqueous tetramethylammonium hydroxide solution without going through a dry etching process. Although a method for forming a miniaturized resist pattern has been disclosed, all of these are resists. A method of refining the turn itself, quite different from the present invention and its purpose.
JP-A-5-166717 JP-A-5-241348 Japanese Patent Laid-Open No. 10-073927 JP-A-1-307228 Japanese Patent Laid-Open No. 4-364221 JP 7-45510 A JP 2003-084459 A JP 2003-084460 A JP 2003-107752 A JP 2003-142381 A JP 2003-195527 A JP 2003-202679 A JP 2001-281886 A JP 2002-184673 A

  The present invention has been made in view of the above circumstances, and does not cause defects after the miniaturization process. In particular, even in the miniaturization process of a resist pattern with an ultra-fine size of 120 nm or less and a high aspect ratio. The resist pattern shape after the miniaturization process can be satisfactorily maintained while the desired miniaturization amount is maintained, and further, a coating forming agent for pattern miniaturization is applied. It is an object of the present invention to provide a coating forming agent for pattern miniaturization that can eliminate defects due to the generation of bacteria or the like in the wafer surface after the process and a fine pattern forming method using the same.

  In order to solve the above-mentioned problems, the present invention is a coating forming agent for pattern miniaturization which is coated on a substrate having a photoresist pattern and is used for forming a fine pattern, comprising: (a) a water-soluble polymer; (B) A coating forming agent for pattern miniaturization comprising a carboxyl group-containing compound or a salt or esterified product thereof, a peroxide, and at least one selected from peracids.

  In the present invention, the pattern refinement coating forming agent is coated on a substrate having a photoresist pattern, and then the pattern refinement coating forming agent is thermally contracted by heat treatment, and then the pattern refinement coating formation is performed. There is provided a method for forming a fine pattern comprising a step of removing an agent.

  In a technique for forming a fine pattern by providing a coating film forming agent for pattern miniaturization on a substrate having a photoresist pattern, there is no defect after the miniaturization process, and in particular, ultra-fine, high aspect ratio of 120 nm or less Even in the miniaturization process of the resist pattern that has been compared, miniaturization due to fluctuations in the heat treatment temperature within the wafer surface, the presence of dense patterns mixed within the wafer surface, and other errors between production lots and production day errors. It is possible to suppress and manage fluctuations in quantity. In addition, it is possible to maintain and control the resist pattern shape after the miniaturization process well while maintaining the desired miniaturization amount. Furthermore, problems due to the generation of bacteria or the like can be eliminated within the wafer surface after the coating forming agent is applied.

≪Coating forming agent for pattern refinement≫
The pattern refining coating forming agent (hereinafter simply referred to as “coating forming agent”) of the present invention includes (a) a water-soluble polymer, (b) a carboxyl group-containing compound or a salt or esterified product thereof, a peroxide, And an aqueous solution containing at least one selected from peracids.

<(A) Water-soluble polymer>
The water-soluble polymer of component (a) is not particularly limited as long as it is a polymer that can be dissolved in water at room temperature. In the present invention, for example, it is composed of at least one monomer selected from acrylic acid, methyl acrylate, methacrylic acid , N -acryloylmorpholine, and N-vinylpyrrolidone, vinyl acetate, and N-vinylimidazolidinone. A polymer or copolymer, or a mixed polymer thereof can be used.

  In addition, in the present invention, as the cellulose-based resin, for example, hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcellulose acetate phthalate, hydroxypropylmethylcellulose hexahydrophthalate, hydroxypropylmethylcellulose acetate succinate, hydroxypropylmethylcellulose, hydroxypropylcellulose, hydroxyethyl Cellulose, cellulose acetate hexahydrophthalate, carboxymethylcellulose, ethylcellulose, methylcellulose and the like can be used.

  Among them, as the component (a) used in the present invention, a polymer and / or copolymer of at least one monomer selected from N-vinylpyrrolidone and vinyl alcohol is preferable, and in particular, a polymer of polyvinylpyrrolidone. It is preferable that

  Furthermore, it is preferable that the mass average molecular weight of such (a) component shall be 50000-300000.

  The blending amount of the component (a) in the present invention is appropriately adjusted within a range in which a necessary and sufficient film thickness can be obtained when a coating film is provided on the resist pattern. Among them, the content is preferably about 1 to 99% by mass, more preferably about 40 to 99% by mass, and still more preferably about 65 to 99% by mass.

<(B) At least one selected from carboxyl group-containing compounds or salts or esterified products thereof, peroxides, and peracids>
Examples of the carboxyl group-containing compound include acetic acid, fumaric acid, adipic acid, sorbic acid, benzoic acid, hydroxybenzoic acid, caproic acid, caprylic acid, capric acid, lauric acid and the like. Examples of the salt of the carboxyl group-containing compound include sorbic acid and benzoic acid sodium salt and potassium salt. Furthermore, as esterified products of carboxyl group-containing compounds, caproic acid, caprylic acid, capric acid, lauric acid and the like and esters of glycerin, methyl-4-hydroxybenzoic acid, ethyl-4-hydroxybenzoic acid, propyl-4- Examples thereof include hydroxybenzoic acid, isopropyl-4-hydroxybenzoic acid, butyl-4-hydroxybenzoic acid, isobutyl-4-hydroxybenzoic acid, and benzyl-4-hydroxybenzoic acid.

  Examples of the peroxide include hydrogen peroxide, ethyl hydroxy peroxide, tert-butyl peroxide, diethyl peroxide, di-tert-butyl peroxide, and diacetyl peroxide.

  Examples of the peracid include formic acid, peracetic acid, perpropionic acid, and the like.

  Among the above-exemplified components (b), hydrogen peroxide and / or peracetic acid are most preferable. Moreover, it is preferable to mix | blend 0.001-3 mass parts of such (b) component with respect to 100 mass parts of (a) component mentioned above, Especially, blending 0.01-1 mass part. Is preferred.

  The coating forming agent of the present invention is usually used as an aqueous solution containing the above components (a) and (b). This coating forming agent is preferably used as a solid content mass concentration of 3 to 50 mass%, more preferably 5 to 20 mass%.

  In addition, although using as aqueous solution is preferable, as long as the effect of this invention is not impaired, it is good also as a mixed solvent of water and an alcohol solvent. Examples of such alcohol solvents include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, glycerin, ethylene glycol, propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, and 2,3-butylene. Glycol and the like. These alcohol solvents are used by mixing 30 parts by mass with respect to 100 parts by mass of water.

  The coating forming agent of the present invention contains the above components (a) and (b), so that no defects occur after the miniaturization treatment, and in particular, a resist having an ultrafine size of 120 nm or less and a high aspect ratio. Also in pattern miniaturization processing, fluctuations in the amount of miniaturization due to fluctuations in the heat treatment temperature within the wafer surface, the presence of sparse and dense patterns mixed in the wafer surface, and other errors between manufacturing lots and manufacturing day errors, etc. It can be controlled and managed. In addition, it is possible to maintain and control the resist pattern shape after the miniaturization process well while maintaining the desired miniaturization amount. Furthermore, problems due to the generation of bacteria or the like can be eliminated within the wafer surface after the coating forming agent is applied.

  Further, in the present invention, the following water-soluble crosslinking agent, surfactant, water-soluble fluorine compound, amide group-containing monomer, at least as long as the effect of the present invention is not impaired, as necessary, with respect to the coating forming agent. A heterocyclic compound having an oxygen atom and / or a nitrogen atom, a heterocyclic compound having at least two nitrogen atoms in the same ring, a water-soluble amine compound, a non-amine water-soluble organic solvent, etc. Good. Examples of such optionally added components include the following.

-Water-soluble crosslinking agent As the water-soluble crosslinking agent, a nitrogen-containing compound having an amino group and / or an imino group in which at least two hydrogen atoms are substituted with a hydroxyalkyl group and / or an alkoxyalkyl group is preferably used. Examples of these nitrogen-containing compounds include melamine derivatives, urea derivatives, guanamine derivatives, acetoguanamine derivatives, benzoguanamine derivatives in which a hydrogen atom of an amino group is substituted with a methylol group, an alkoxymethyl group, or both. Derivatives, succinylamide derivatives, glycoluril derivatives in which a hydrogen atom of an imino group is substituted, ethyleneurea derivatives, and the like.

  Among these nitrogen-containing compounds, from the viewpoint of crosslinking reactivity, at least two hydrogen atoms are substituted with a methylol group, a lower alkoxymethyl group having 1 to 6 carbon atoms, or both, an amino group and / or One or more of triazine derivatives such as benzoguanamine derivatives, guanamine derivatives, melamine derivatives, glycoluril derivatives, and urea derivatives having an imino group are preferred.

  When such a water-soluble crosslinking agent is added, the addition amount is preferably adjusted to about 1 to 35% by mass in the solid content of the coating forming agent.

-Surfactant As a surfactant, the above-mentioned (a) water-soluble polymer has high solubility and does not generate suspension. By using a surfactant that satisfies these characteristics, it is possible to suppress the generation of bubbles (microfoam), particularly when applying a coating forming agent, and to prevent the occurrence of defects that are related to the occurrence of microfoam. It can prevent more effectively. From the above points, one or more of N-alkylpyrrolidone surfactants, quaternary ammonium salt surfactants, polyoxyethylene phosphate ester surfactants, and nonionic surfactants are preferably used. It is done.

  As said N-alkyl pyrrolidone type-surfactant, what is represented by following General formula (1) is preferable.

In the general formula (1), R ²⁰ represents an alkyl group having 6 or more carbon atoms.

  Specific examples of such N-alkylpyrrolidone surfactants include N-hexyl-2-pyrrolidone, N-heptyl-2-pyrrolidone, N-octyl-2-pyrrolidone, N-nonyl-2-pyrrolidone, N- Decyl-2-pyrrolidone, N-decyl-2-pyrrolidone, N-undecyl-2-pyrrolidone, N-dodecyl-2-pyrrolidone, N-tridecyl-2-pyrrolidone, N-tetradecyl-2-pyrrolidone, N-pentadecyl- Examples include 2-pyrrolidone, N-hexadecyl-2-pyrrolidone, N-heptadecyl-2-pyrrolidone, and N-octadecyl-2-pyrrolidone. Among these, N-octyl-2-pyrrolidone (“SURFADONE LP100”; manufactured by ISP) is preferably used.

  As said quaternary ammonium type surfactant, what is represented by following General formula (2) is preferable.

In the general formula (2), R ²¹ , R ²² , R ²³ and R ²⁴ each independently represent an alkyl group or a hydroxyalkyl group (however, at least one of them is an alkyl group having 6 or more carbon atoms) Or a hydroxyalkyl group), X ⁻ represents a hydroxide ion or a halogen ion.

  Specific examples of the quaternary ammonium surfactant include dodecyltrimethylammonium hydroxide, tridecyltrimethylammonium hydroxide, tetradecyltrimethylammonium hydroxide, pentadecyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, Examples include heptadecyltrimethylammonium hydroxide and octadecyltrimethylammonium hydroxide. Of these, hexadecyltrimethylammonium hydroxide is preferably used.

  As the polyoxyethylene phosphate ester surfactant, one represented by the following general formula (3) is preferable.

In the general formula ^{(3), R 25} represents an alkyl group or an alkyl aryl group having 1 to 10 carbon ^{atoms, R 26} is a hydrogen atom or a ^{_{(CH 2 CH 2 O) R}} 25 (R 25 in the above And x represents an integer of 1 to 20.

  Specifically, such polyoxyethylene phosphate ester surfactants are commercially available as "Plisurf A212E", "Plysurf A210G" (all of which are manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). A thing can be used suitably.

  The nonionic surfactant is preferably a polyoxyalkylene alkyl ether or an alkylamine oxide compound.

  As the polyoxyalkylene alkyl ether compound, a compound represented by the following general formula (4) or (5) is preferably used.

In the general formulas (4) and (5), R ²⁷ and R ²⁸ are each a linear, branched or cyclic alkyl group having 1 to 22 carbon atoms, an alkyl group having a hydroxyl group, or an alkylphenyl group. Indicates. A ₀ is an oxyalkylene group, and is preferably at least one selected from oxyethylene, oxypropylene, and oxybutylene groups. y is an integer.

As the alkylamine oxide compound, a compound represented by the following general formula (6) or (7) is preferably used.

In the general formulas (6) and (7), R ²⁹ represents an alkyl group or hydroxyalkyl group having 8 to 20 carbon atoms which may be interrupted by an oxygen atom, and p and q are integers of 1 to 5. Indicates.

  Examples of the alkylamine oxide compounds represented by the general formulas (6) and (7) include octyldimethylamine oxide, dodecyldimethylamine oxide, decyldimethylamine oxide, lauryldimethylamine oxide, cetyldimethylamine oxide, stearyldimethylamine oxide. , Isohexyl diethylamine oxide, nonyl diethylamine oxide, lauryl diethylamine oxide, isopentadecylmethylethylamine oxide, stearylmethylpropylamine oxide, lauryldi (hydroxyethyl) amine oxide, cetyldiethanolamine oxide, stearyldi (hydroxyethyl) amine oxide, dodecyloxy Ethoxyethoxyethyl di (methyl) amine oxide, stearyloxyethyl di (methyl) ) Amine oxides, and the like.

  Among these surfactants, nonionic surfactants are preferably used particularly from the viewpoint of reducing defects.

  In the case of adding such a surfactant, the amount added is preferably about 1 ppm to 10% by mass, more preferably about 100 ppm to 2% by mass in the solid content of the coating forming agent. .

-Water-soluble fluorine compound As a water-soluble fluorine compound, the property which is highly soluble with respect to said (a) water-soluble polymer, and a suspension does not generate | occur | produce is required. By using a water-soluble fluorine compound that satisfies such characteristics, the leveling property (the degree of spread of the coating forming agent) can be further improved. This leveling property can be achieved by lowering the contact angle by adding an excessive amount of surfactant. However, when the surfactant addition amount is excessive, a certain level of coating improvement is not observed. However, if the amount is excessive, bubbles (microfoam) are generated on the coating film when applied, which may cause defects. By blending this water-soluble fluorine compound, the contact angle can be lowered and the leveling property can be improved while suppressing such foaming.

  As such a water-soluble fluorine compound, fluoroalkyl alcohols, fluoroalkylcarboxylic acids and the like are preferably used. Examples of fluoroalkyl alcohols include 2-fluoro-1-ethanol, 2,2-difluoro-1-ethanol, trifluoroethanol, tetrafluoropropanol, and octafluoroamyl alcohol. Examples of the fluoroalkylcarboxylic acids include trifluoroacetic acid. However, it is not limited to these examples, and is not limited as long as it is a fluorinated material having water solubility and exhibits the above-described effects. In particular, fluoroalkyl alcohols having 6 or less carbon atoms are preferably used. Of these, trifluoroethanol is particularly preferable from the viewpoint of availability.

  In the case of adding such a water-soluble fluorine compound, the addition amount is preferably about 0.1 to 30% by mass in the solid content of the coating forming agent, and particularly adjusted to about 0.1 to 15% by mass. It is preferable to do.

Amide group-containing monomer The amide group-containing monomer is not particularly limited, but it must have characteristics such as high solubility in the water-soluble polymer (a) and no suspension.

  As such an amide group-containing monomer, an amide compound represented by the following general formula (8) is preferably used.

In the general formula (8), R ³⁰ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a hydroxyalkyl group, R ³¹ represents an alkyl group having 1 to 5 carbon atoms, and R ³² Represents a hydrogen atom or a methyl group, and z represents an integer of 0 to 5. In the above, the alkyl group and the hydroxyalkyl group include both linear and branched chains.

In the general formula (8), an amide group-containing monomer in which R ³⁰ represents a hydrogen atom, a methyl group, or an ethyl group and z is 0 is more preferably used. Specific examples of the amide group-containing monomer include acrylamide, methacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-ethyl acrylamide, N-ethyl methacrylamide, etc. are mentioned. Of these, acrylamide and methacrylamide are particularly preferable.

  The addition amount in the case of adding such an amide group-containing monomer is preferably about 0.1 to 30% by mass, particularly about 1 to 15% by mass in the solid content of the coating forming agent. Is preferred.

-Heterocyclic compound having at least an oxygen atom and / or a nitrogen atom A heterocyclic compound having at least an oxygen atom and / or a nitrogen atom may be blended. As such a heterocyclic compound, at least one selected from a compound having an oxazolidine skeleton, a compound having an oxazoline skeleton, a compound having an oxazolidone skeleton, and a compound having an oxazolidinone skeleton is preferably used.

  Examples of the compound having an oxazolidine skeleton include oxazoline represented by the following chemical formula (9), and substituted products thereof.

  As the substituent, the hydrogen atom bonded to the carbon atom or nitrogen atom of the oxazoline represented by the chemical formula (9) is a substituted or unsubstituted lower alkyl group having 1 to 6 carbon atoms, a carboxyl group, a hydroxyl group, Examples thereof include compounds substituted with a halogen group. Examples of the substituted lower alkyl group include a hydroxyalkyl group and a lower alkoxyalkyl group, but are not limited to these examples.

  Examples of the compound having an oxazoline skeleton include 2-oxazoline represented by the following chemical formula (8-1), 3-oxazoline represented by the chemical formula (8-2), and 4- represented by the chemical formula (8-3). In addition to oxazoline, those substitution products are exemplified.

  As the substituent, a hydrogen atom bonded to a carbon atom or a nitrogen atom of the compound having an oxazoline skeleton represented by the above chemical formulas (8-1) to (8-3) is substituted or substituted with 1 to 6 carbon atoms. Examples thereof include compounds substituted with an unsubstituted lower alkyl group, a carboxyl group, a hydroxyl group, and a halogen group. Examples of the substituted lower alkyl group include a hydroxyalkyl group and a lower alkoxyalkyl group, but are not limited to these examples.

  Among the compounds having the oxazoline skeleton, 2-methyl-2-oxazoline represented by the following chemical formula (8-1-A) is preferably used.

  Examples of the compound having an oxazolidone skeleton include 5 (4) -oxazolone represented by the following chemical formula (9-1), 5 (2) -oxazolone represented by the following chemical formula (9-2), and the following chemical formula (9- In addition to 4 (5) -oxazolone represented by 3), 2 (5) -oxazolone represented by the following chemical formula (9-4), 2 (3) -oxazolone represented by the following chemical formula (9-5) , And their substitutes.

  As the substituent, a hydrogen atom bonded to a carbon atom or a nitrogen atom of the compound having an oxazolidone skeleton represented by the above chemical formulas (9-1) to (9-5) is substituted or substituted with 1 to 6 carbon atoms. Examples thereof include compounds substituted with an unsubstituted lower alkyl group, a carboxyl group, a hydroxyl group, and a halogen group. Examples of the substituted lower alkyl group include a hydroxyalkyl group and a lower alkoxyalkyl group, but are not limited to these examples.

  Examples of the compound having an oxazolidinone skeleton (or a compound having a 2-oxazolidone skeleton) include an oxazolidinone (or 2-oxazolidone) represented by the following chemical formula (10) and a substituted product thereof.

  Examples of the substituent include a substituted or unsubstituted lower alkyl group in which the hydrogen atom bonded to the carbon atom or nitrogen atom of the oxazolidinone (or 2-oxazolidone) represented by the chemical formula (10) is 1 to 6 carbon atoms. , A compound substituted with a carboxyl group, a hydroxyl group or a halogen group. Examples of the substituted lower alkyl group include a hydroxyalkyl group and a (lower alkoxy) alkyl group, but are not limited to these examples.

  Among the compounds having the oxazolidinone skeleton, 3-methyl-2-oxazolidone represented by the following chemical formula (10-1) is preferably used.

  The addition amount in the case of adding such a heterocyclic compound having at least an oxygen atom and / or a nitrogen atom is preferably 1 to 50% by mass, more preferably based on the water-soluble polymer (a). It is preferable to adjust to 3-20 mass%.

A heterocyclic compound having at least two nitrogen atoms in at least the same ring At least two heterocyclic compounds having at least two nitrogen atoms in the same ring include pyrazole, 3,5-dimethylpyrazole, 2-pyrazoline 5-pyrazolone, 3-methyl-1-phenyl-5-pyrazolone, 2,3-dimethyl-1-phenyl-5-pyrazolone, 2,3-dimethyl-4-dimethylamino-1-phenyl-5-pyrazolone, Pyrazole compounds such as benzopyrazole; imidazoles such as imidazole, methylimidazole, 2,4,5-triphenylimidazole, 4- (2-aminoethyl) imidazole, 2-amino-3- (4-imidazolyl) propionic acid Compound; 2-imidazoline, 2,4,5-triphenyl-2-imidazoline, 2- (1-naphthyl) Imidazoline compounds such as methyl) -2-imidazoline; imidazolidine, 2-imidazolidone, 2,4-imidazolidinedione, 1-methyl-2,4-imidazolidinedione, 5-methyl-2,4-imidazolidinedione 5-hydroxy-2,4-imidazolidinedione-5-carboxylic acid, 5-ureido-2,4-imidazolidinedione, 2-imino-1-methyl-4-imidazolidone, 2-thioxo-4-imidazolidone, etc. An imidazolidine compound of the above; benzimidazole compounds such as benzimidazole, 2-phenylbenzimidazole, 2-benzimidazolinone; 1,2-diazine, 1,3-diazine, 1,4-diazine, 2,5-dimethyl Diazine compounds such as pyrazine; 2,4 (1H, 3H) pyrimidinedione, 5-methyl Uracil, 5-ethyl-5-phenyl-4,6-perhydropyrimidinedione, 2-thioxo-4 (1H, 3H) -pyrimidinone, 4-imino-2 (1H, 3H) -pyrimidine, 2,4,6 Hydropyrimidine compounds such as (1H, 3H, 5H) -pyrimidinetrione; benzodiazine compounds such as cinnoline, phthalazine, quinazoline, quinoxaline and luminol; dibenzodiazine compounds such as benzocinoline, phenazine and 5,10-dihydrophenazine; Triazole compounds such as 1H-1,2,3-triazole, 1H-1,2,4-triazole and 4-amino-1,2,4-triazole; benzotriazoles such as benzotriazole and 5-methylbenzotriazole Compound; 1,3,5-triazine, 1,3,5-triazi -2,4,6-triol, 2,4,6-trimethoxy-1,3,5-triazine, 1,3,5-triazine-2,4,6-trithiol, 1,3,5-triazine-2 , 4,6-triamine, triazine compounds such as 4,6-diamino-1,3,5-triazin-2-ol, and the like, but are not limited to these examples.

  Among these, from the viewpoints of easy handling and availability, imidazole compound monomers are preferably used, and imidazole is particularly preferably used.

  The addition amount in the case of adding a heterocyclic compound having two or more nitrogen atoms in at least the same ring is preferably about 1 to 15% by mass relative to the water-soluble polymer (a). More preferably, it is preferably adjusted to about 2 to 10% by mass.

-Water-soluble amine compound By using such a water-soluble amine compound, it becomes possible to further prevent the generation of impurities, adjust the pH, and the like.

  Examples of the water-soluble amine compound include amines having a pKa (acid dissociation constant) of 7.5 to 13 in an aqueous solution at 25 ° C. Specifically, for example, monoethanolamine, diethanolamine, triethanolamine, 2- (2-aminoethoxy) ethanol, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine , Alkanolamines such as N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine; diethylenetriamine, triethylenetetramine, propylenediamine, N, N-diethylethylenediamine, 1,4-butanediamine, N-ethyl-ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,6-hexane Polyalkylene polyamines such as amines; aliphatic amines such as 2-ethyl-hexylamine, dioctylamine, tributylamine, tripropylamine, triallylamine, heptylamine, cyclohexylamine; aromatic amines such as benzylamine and diphenylamine Cyclic amines such as piperazine, N-methyl-piperazine, and hydroxyethylpiperazine; Among them, those having a boiling point of 140 ° C. or higher (under 760 mmHg) are preferable, and for example, monoethanolamine, triethanolamine and the like are preferably used.

  In the case of adding such a water-soluble amine compound, the amount added is preferably about 0.1 to 30% by mass in the solid content of the coating forming agent, and particularly adjusted to about 2 to 15% by mass. Is preferred.

-Non-amine water-soluble organic solvent By incorporating a non-amine water-soluble organic solvent, the occurrence of defects can be further suppressed.

  Such a non-amine water-soluble organic solvent may be any non-amine organic solvent miscible with water, such as sulfoxides such as dimethyl sulfoxide; dimethyl sulfone, diethyl sulfone, bis (2-hydroxyethyl) sulfone, Sulfones such as tetramethylene sulfone; Amides such as N, N-dimethylformamide, N-methylformamide, N, N-dimethylacetamide, N-methylacetamide, N, N-diethylacetamide; N-methyl-2-pyrrolidone N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, lactams such as N-hydroxyethyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone 1,3-diethyl-2-imidazolidinone, 1,3-diiso Imidazolidinones such as propyl-2-imidazolidinone; ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol, diethylene glycol monomethyl Polyhydric alcohols such as ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol, propylene glycol monomethyl ether, glycerin, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol and their derivatives Is mentioned. Among them, polyhydric alcohols and derivatives thereof are preferable from the viewpoint of suppressing the occurrence of defects, and glycerin is particularly preferable. One or more non-amine water-soluble organic solvents can be used.

  The addition amount when such a non-amine water-soluble organic solvent is added is preferably about 0.1 to 30% by mass, particularly 0.5 to 15%, based on the water-soluble polymer (a). It is preferable to adjust to about mass%.

  The method for forming a fine pattern according to the present invention includes a step of coating a substrate having a resist pattern with the coating forming agent, heat-treating the coating forming agent, and then removing the coating forming agent. Including.

  The production of the substrate having a resist pattern is not particularly limited, and can be performed by a conventional method used in the production of semiconductor devices, liquid crystal display elements, magnetic heads, microlenses, and the like. For example, a photoresist composition of chemical amplification type or the like is applied onto a substrate such as a silicon wafer by using a spinner or the like and dried to form a photoresist layer, and then ultraviolet, deep-UV, or excimer is used by a reduction projection exposure apparatus or the like. An actinic ray such as a laser beam is irradiated through a desired mask pattern in a vacuum or through a liquid having a predetermined refractive index, or is drawn with an electron beam and then heated, and then this is applied to a developer. For example, a photoresist pattern can be formed on a substrate by developing with an alkaline aqueous solution such as an aqueous solution of 1 to 10% by mass tetramethylammonium hydroxide (TMAH).

As the photoresist composition which is a material of the resist pattern, is not particularly limited, i, g-line photoresist composition, KrF, ArF, excimer laser photoresist composition, such as F _2, further EB Widely and commonly used photoresist compositions such as (electron beam) photoresist compositions and EUV photoresists can be used.

a. Coating Forming Agent Application Step Next, a coating forming agent is applied and coated over the entire surface of the substrate having the photoresist pattern as such a mask pattern. In addition, after apply | coating this coating formation agent, you may pre-bake a board | substrate at the temperature of 80-100 degreeC for 30 to 90 second.

  The coating method can be performed in accordance with a method usually performed in a conventional heat flow process. That is, for example, the aqueous solution of the coating forming agent is applied onto the substrate by a known application means such as a bar coater method, a roll coater method, a slit coater method, or spin coating using a spinner.

b. Heat treatment step Next, heat treatment is performed to shrink the coating film made of the coating forming agent. Due to the shrinkage action of the coating film, the photoresist pattern in contact with the coating film becomes wide and wide corresponding to the shrinkage of the coating film, so that the photoresist patterns are in close proximity to each other and the interval between the photoresist patterns is narrowed.

  The heat treatment temperature is not particularly limited as long as it is a temperature that can cause shrinkage of the coating film made of the coating forming agent and is sufficient for pattern miniaturization. It is preferred to heat at a temperature that does not cause The temperature at which the photoresist pattern does not cause thermal flow means that when a coating film made of a coating forming agent is not formed and a substrate on which only the photoresist pattern is formed is heated, the photoresist pattern changes in dimensions (for example, due to spontaneous flow). Temperature that does not cause dimensional change. The heat treatment at such a temperature makes it possible to more effectively form a fine pattern with a good profile, and particularly depends on the duty ratio in the wafer surface, that is, the pattern interval in the wafer surface. This is extremely effective in that the property can be reduced. Considering the temperature at which thermal flow of various photoresist compositions used in the current photolithography technology begins to occur, the preferred heat treatment is usually in the temperature range of about 80-180 ° C., but at a temperature at which the photoresist does not cause thermal flow. For about 30 to 90 seconds.

  Further, the thickness of the coating film made of the coating forming agent is preferably about the same as the height of the photoresist pattern or a height that covers it.

c. Coating Forming Agent Removal Step Thereafter, the coating film made of the coating forming agent remaining on the substrate having the photoresist pattern is removed by washing with an aqueous solvent, preferably pure water, for 10 to 60 seconds. Prior to the water removal, a rinse treatment may be performed with an alkaline aqueous solution (for example, tetramethylammonium hydroxide (TMAH), choline, etc.) as desired. The coating forming agent according to the present invention can be easily removed by washing with water, and can be completely removed from the substrate and the photoresist pattern.

  Then, a substrate having a miniaturized pattern defined between the wide and wide photoresist patterns is obtained on the substrate.

  The fine pattern obtained by the present invention has a finer pattern size than the resolution limit obtained by the conventional methods, a good resist pattern shape, and physical properties that can sufficiently satisfy the required required characteristics. It is equipped with.

  In addition, you may perform the said ac process repeatedly several times. In this way, by repeating the steps a to c a plurality of times, the photoresist pattern can be gradually widened and widened.

The technical field to which the present invention is applied is not limited to the semiconductor field, and can be widely used for manufacturing liquid crystal display elements, magnetic heads, and microlenses.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[Coating agent A]
400 ppm of peracetic acid was blended in a 4% by mass aqueous solution of polyvinylpyrrolidone with respect to the total mass of polyvinylpyrrolidone to obtain a coating forming agent A.

[Coating agent B]
600 ppm of peracetic acid was blended in a 4% by mass aqueous solution of polyvinylpyrrolidone with respect to the total mass of polyvinylpyrrolidone to obtain a coating forming agent B.

[Coating agent C]
200 ppm of peracetic acid was blended in a 4% by mass aqueous solution of polyvinylpyrrolidone with respect to the total mass of polyvinylpyrrolidone to obtain a coating forming agent C.

[Coating agent D]
As a phosphoric acid ester surfactant of 7.0 g of a copolymer (AA: VP = 2: 1.3 (polymerization ratio)) of acrylic acid / vinyl pyrrolidone (AA / VP), triethylamine 6 g, and polyoxyethylene 1 g of Surf A210G (Daiichi Kogyo Seiyaku Co., Ltd.) was dissolved in pure water, and the total amount was adjusted to 100 g.

[Coating agent E]
A 4 mass% aqueous solution of polyvinyl alcohol was prepared and used as a coating forming agent E.

  On the other hand, a positive photoresist TARF-P7066 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated on an 8-inch silicon wafer and baked at 135 ° C. for 60 seconds to form a photoresist layer having a thickness of 200 nm.

  The photoresist layer is exposed using an exposure apparatus NSR-S306 (manufactured by Nikon Corporation), and subjected to a heat treatment at 110 ° C. for 60 seconds to obtain 2.38 mass% TMAH (tetramethylammonium hydroxide). Development processing was performed using an aqueous solution to form a hole pattern having a diameter of 120 nm (hole pattern diameter: distance between hole patterns = 1: 1).

  Next, on the silicon wafer on which the resist pattern is formed, the coating forming agents A to E are respectively applied to form a coating film having a film thickness of 200 nm, and the wafer is heated at 150 ° C. for 60 seconds, The hole pattern was refined. Subsequently, the coating forming agent was removed using pure water at 23 ° C.

  About these refinement | miniaturization processes, the evaluations 1-6 shown below were performed, respectively. The results are shown in Table 1.

Evaluation 1: Presence or absence of defect occurrence The substrate after the above-described miniaturization treatment was observed with KLA (manufactured by KLA Tencor), and the number of defects was counted. The number of defects at this time was defined as 100% of the result of performing the micronization treatment using the coating forming agent E, while the results when other coating forming agents were used are shown in Table 1, respectively.

Evaluation 2: Variation in the amount of refinement due to variation in heat treatment temperature The heat treatment in the above-described refinement treatment was performed at 4 points of 130 ° C., 140 ° C., 150 ° C., and 160 ° C., respectively. The dimension of the resist pattern after the miniaturization treatment was measured with a scanning electron microscope. The amount of change in the amount of refinement per 1 ° C. was calculated from the amount of change in the amount of refinement at this time and is shown in Table 1.

Evaluation 3: Fluctuation in the amount of miniaturization of the dense pattern In the pattern in which the distance between the hole patterns of the above-described hole pattern is 1 time (equal size), 1.5 times, 2 times, and 5 times the hole pattern diameter. On the other hand, the respective fine processing was performed. The resist pattern after the micronization treatment at this time was measured with a scanning electron microscope, and the difference between the minimum and maximum micronization amounts is shown in Table 1, respectively.

Evaluation 4: Resist pattern shape after miniaturization treatment The resist pattern shape after the above-described miniaturization treatment was observed and evaluated with a scanning electron microscope. As a result, a resist pattern having a good rectangular shape is shown as A, and a resist pattern having a non-rectangular shape as B is shown in Table 1.

Evaluation 5: Amount of refinement The resist pattern size after the above-described refinement treatment was measured with a scanning electron microscope. Table 1 shows the amount of fineness when the initial resist pattern dimensions were refined.

Evaluation 6: Presence / absence of bacteria generation Before applying the above-described coating forming agent, after filtering using Millpore MX00TT220, which is a filter for aerobic heterotrophic bacteria, the substrate after applying this was left at room temperature for 3 days, The presence or absence of bacteria was visually evaluated. As a result, those in which no bacteria were generated were shown in Table 1, and those in which bacteria were generated were shown in Table 1, respectively.

  In the above examples, except that the positive photoresist is TARF-P7152 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), all the same miniaturization treatments are performed, and evaluations similar to the evaluations 1 to 6 above are performed. Went. The results are shown in Table 2.

Claims (14)

A coating forming agent for pattern miniaturization used for forming a fine pattern by coating a substrate having a photoresist pattern, narrowing the interval of the photoresist pattern by utilizing its thermal shrinkage, and then removing the coating. Because
(A) a water-soluble polymer (excluding an amino group-containing water-soluble polymer) and (b) a carboxyl group-containing compound (excluding 1-phenyl-1-cyclopropanecarboxylic acid) or a salt or esterified product thereof, A coating forming agent for pattern miniaturization, comprising at least one selected from peroxides and peracids and not containing a crosslinking agent. The component (a) is composed of at least one monomer selected from acrylic acid, methyl acrylate, methacrylic acid , N -acryloylmorpholine, and N-vinylpyrrolidone, vinyl acetate, and N-vinylimidazolidinone. The coating forming agent for pattern miniaturization according to claim 1, which is a polymer or a copolymer, or a mixed polymer thereof.   3. The fine pattern according to claim 1, wherein the component (a) is a polymer and / or copolymer of at least one monomer selected from N-vinylpyrrolidone and vinyl acetate. Coating forming agent.   The coating forming agent for pattern miniaturization according to any one of claims 1 to 3, wherein the component (a) is polyvinylpyrrolidone.   The coating forming agent for pattern miniaturization according to any one of claims 1 to 4, wherein the component (a) is a water-soluble polymer having a mass average molecular weight of 50,000 to 300,000.   6. The pattern refinement coating according to claim 1, wherein the carboxyl group-containing compound is at least one selected from sorbic acid, paraoxybenzoic acid, and benzoic acid. Forming agent.   The coating forming agent for pattern miniaturization according to any one of claims 1 to 5, wherein the peroxide is hydrogen peroxide.   6. The coating forming agent for pattern miniaturization according to claim 1, wherein the peracid is at least one selected from peracetic acid and perpropionic acid.   The coating forming agent for pattern miniaturization according to any one of claims 1 to 5, wherein the component (b) is at least one selected from hydrogen peroxide and peracetic acid.   The coating forming agent for pattern miniaturization according to any one of claims 1 to 9, which is an aqueous solution having a solid content concentration of 1 to 50% by mass.   The coating for pattern miniaturization according to any one of claims 1 to 10, comprising 0.001 to 3 parts by mass of the component (b) with respect to 100 parts by mass of the component (a). Forming agent.   The coating for pattern miniaturization according to any one of claims 1 to 11, wherein 0.01 to 1 part by mass of the component (b) is contained with respect to 100 parts by mass of the component (a). Forming agent. After coating the pattern fine for coating formation agent on a substrate having a photoresist pattern, the fine patterns for coating formation agent and heat-shrunk by heat treatment, caused to narrow the photoresist pattern interval by the heat shrinkage action, then the a step of removing the fine patterns for coating formation agent seen including,
The pattern refining coating-forming agent comprises (a) a water-soluble polymer, (b) a carboxyl group-containing compound (excluding 1-phenyl-1-cyclopropanecarboxylic acid) or a salt or esterified product thereof, and peroxidation. And a method for forming a fine pattern, comprising at least one selected from peracids and not containing a crosslinking agent .   The method of forming a fine pattern according to claim 13, wherein the heat treatment is performed at a temperature at which the photoresist pattern on the substrate does not cause thermal flow.