JP4233091B2 - COATING FORMING AGENT FOR PATTERN REFINEMENT AND METHOD FOR FORMING FINE PATTERN USING THE SAME - Google Patents

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 recent integration and miniaturization of semiconductor devices, and a method for forming a micropattern using the same.

  In the manufacture of electronic components such as semiconductor devices and liquid crystal devices, a coating (photoresist layer) is provided on the substrate using a so-called radiation-sensitive photoresist that is sensitive to actinic radiation when the substrate is subjected to processing such as etching. Selectively irradiate with actinic radiation to expose, develop, and selectively dissolve and remove the photoresist layer to form an image pattern (photoresist pattern) on the substrate, which is used as a protective layer (mask pattern) Photolithographic techniques for forming various patterns such as a contact pattern such as a hole pattern and a trench pattern on a substrate are used.

In recent years, the trend toward integration and miniaturization of semiconductor devices has increased, and the miniaturization of these patterns has progressed. Currently, ultra-fine processing with a pattern width of 0.20 μm or less is required, and the activity used for mask pattern formation For light, KrF, ArF, F ₂ excimer laser light and short-wavelength irradiation light such as electron beams are used. Photoresist materials as mask pattern forming materials also have physical properties corresponding to these irradiation light.・ Development is in progress.

  In addition to countermeasures for ultra-miniaturization from the viewpoint of photoresist materials as described above, research and development of pattern miniaturization techniques that exceed the resolution limit 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 pattern forming resist, and a non-mixing portion of the resist for generating the mixing is removed to reduce the size of the mixing layer. Is disclosed. Further, in Patent Document 2 (Japanese Patent Laid-Open No. 5-241348), 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-treated. After the acid is diffused from the resist to form a resist having a constant thickness near the resin / resist pattern interface, development is performed to remove the resin portion where the acid is not diffused, thereby obtaining the above-mentioned constant thickness dimension. A pattern forming method for miniaturization of the pattern is disclosed.

  However, in these methods, it is difficult to control the thickness of the layer formed on the side wall of the resist pattern, and the thermal dependence in the wafer surface is as large as about 10 nm / ° C., and the heating apparatus used in the manufacture of current semiconductor devices. However, it is very difficult to keep the wafer surface uniform, and there is a problem that variations in pattern dimensions are noticeable. In addition, in the technique shown in Patent Document 2, since the degree of pattern miniaturization varies greatly depending on the acid content of the resist used, the resist selection dependency is high and defects tend to occur frequently.

  On the other hand, a method is also known in which a resist pattern is fluidized by heat treatment or the like to reduce a pattern dimension. For example, Patent Document 3 (Japanese Patent Laid-Open 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. Has been. Patent Document 4 (Japanese Patent Laid-Open No. 4-340221) discloses a method of forming a fine pattern by forming a resist pattern and then heating and changing the pattern dimensions by fluidizing the resist.

  These methods have a thermal dependency on the wafer surface of several nanometers / ° C. Although there are few problems in this respect, it is difficult to control the deformation and flow of the resist by heat treatment, so it is uniform on the wafer surface. There is a problem that it is difficult to provide a simple resist pattern.

  As a further developed method, for example, in Patent Document 5 (Japanese Patent Laid-Open No. 7-45510), after a resist pattern is formed on a substrate, the resist pattern is prevented from flowing too much on the substrate. A method is disclosed in which a resin as a stopper is formed, then heat-treated, the resist is fluidized to change the pattern dimensions, and then the resin is removed to form a fine pattern. As the resin, polyvinyl alcohol is specifically used. However, polyvinyl alcohol alone has insufficient solubility in water, so it is difficult to completely remove it by washing with water, and a good profile pattern can be formed. In addition to being difficult and not always satisfactory in terms of stability over time, there are problems such as poor applicability, and it has not been put into practical use.

  Furthermore, there is a problem of bubbles (micro foam) generation when applying a coating material on a substrate having a photoresist pattern, and it is said that this is ultimately related to the generation of pattern defects called defects. There is a demand for a coating material that can also solve such problems.

  As a technique for solving these conventional problems, the present applicant has disclosed Patent Documents 6 to 11 (JP 2003-084459 A, JP 2003-084460 A, JP 2003-107752 A, JP 2003-142381 A). JP, JP-A 2003-195527, JP-A 2003-202679) and the like propose a technique relating to a pattern forming coating forming agent and a method for forming a fine pattern. The techniques shown in Patent Documents 6 to 11 and the like have made it possible to obtain a fine pattern having controllability of pattern dimensions, a good profile, and required characteristics in a semiconductor device. However, further miniaturization of the pattern is desired. ing.

  In Patent Document 12 (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 13 (Japanese Patent Application Laid-Open No. 2002-184673) discloses a resist pattern on a substrate. After 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 submerging in an aqueous solution of tetramethylammonium hydroxide to refine the film without going through a dry etching process Although methods for forming a resist pattern have been disclosed, all of them are resist patterns. A method of refining the emissions themselves, the present invention and its purpose is completely different.

JP-A-5-166717 JP-A-5-241348 JP-A-1-307228 Japanese Patent Laid-Open No. 4-364221 Japanese Unexamined Patent Publication No. 7-45510 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 finds a new pattern refinement coating forming agent capable of greatly improving the shrink amount (shrinkage amount), and uses this to form a fine pattern capable of realizing further refinement of the pattern. It aims to provide a method.

In order to achieve the above object, the present invention provides a pattern refinement coating forming agent coated on a substrate having a photoresist pattern (however, the pattern refinement coating forming agent causes a crosslinking reaction in the presence of an acid). The coating forming agent is thermally shrunk by performing heat treatment at a temperature that does not cause thermal flow in the photoresist pattern, and the space between the photoresist patterns is narrowed by utilizing the heat shrinking action, and then the above-mentioned Used to form a fine pattern by substantially completely removing the coating forming agent, a water-soluble polymer, a compound having an oxazolidine skeleton, a compound having an oxazoline skeleton, and an oxazolidone skeleton And a small number selected from compounds having an oxazolidinone skeleton. Both provide one for pattern fining coating formation agent containing heterocyclic compound.

  In the present invention, the water-soluble polymer is an alkylene glycol polymer, a cellulose derivative, a vinyl polymer, an acrylic polymer, a urea polymer, an epoxy polymer, a melamine polymer, or an amide polymer. The coating forming agent for pattern miniaturization, which is at least one selected from the inside, is provided.

  The present invention also provides the above-described pattern forming coating forming agent, wherein the water-soluble polymer is at least one selected from an alkylene glycol polymer, a cellulose derivative, a vinyl polymer, and an acrylic polymer.

The present invention also provides the above-described pattern forming coating forming agent, wherein the water-soluble polymer is a copolymer of an acrylic monomer and a vinyl monomer .

Moreover, this invention provides the said coating formation agent for pattern refinement | miniaturization whose coating formation agent is 3-50 mass% solid content aqueous solution.

According to the present invention, a substrate having a photoresist pattern is coated with the coating forming agent for pattern miniaturization according to any one of claims 1 to 5 , and then heated at a temperature that does not cause thermal flow in the photoresist pattern. Forming a fine pattern by thermally shrinking the pattern refining coating forming agent, narrowing the interval between the photoresist patterns by the heat shrinking action, and then substantially completely removing the pattern refining coating forming agent. Provide a method.

  A fine pattern forming method in which a coating forming agent (coating film) is provided on a substrate having a photoresist pattern (mask pattern), the photoresist pattern interval is narrowed by utilizing the shrinkage force of the coating film, and then the coating film is removed. In the technique used, the shrinkage rate of the coating forming agent can be remarkably increased, and this makes it possible to further refine the pattern.

  The coating forming agent for pattern miniaturization of the present invention is for coating a substrate having a photoresist pattern, and the photoresist pattern is widened and widened by the shrinking action of the coating forming agent. This is used to form a minute pattern by narrowing the space between them, that is, the width and width of a pattern such as a hole pattern and a trench pattern defined by a photoresist pattern, and then removing the coating. is there.

  Such a coating forming agent for pattern miniaturization of the present invention contains a water-soluble polymer and a heterocyclic compound having at least an oxygen atom and / or a nitrogen atom.

  The water-soluble polymer is not particularly limited as long as it is a polymer that can be dissolved in water at room temperature at the time of removal of the coating forming agent, but is not limited to acrylic polymer, vinyl polymer, cellulose derivative, alkylene glycol type. A polymer, a urea polymer, a melamine polymer, an epoxy polymer, an amide polymer and the like are preferably used.

  Examples of the acrylic polymer include acrylic acid, methyl acrylate, methacrylic acid, methyl methacrylate, N, N-dimethylacrylamide, N, N-dimethylaminopropyl methacrylamide, N, N-dimethylaminopropylacrylamide, N -A polymer or copolymer comprising monomers such as methyl acrylamide, diacetone acrylamide, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminoethyl acrylate, acryloylmorpholine A polymer is mentioned.

  Examples of the vinyl polymer include a polymer or a copolymer having a constituent component such as N-vinylpyrrolidone, vinylimidazolidinone, vinyl acetate, or the like.

  Examples of cellulose derivatives include hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcellulose acetate phthalate, hydroxypropylmethylcellulose hexahydrophthalate, hydroxypropylmethylcellulose acetate succinate, hydroxypropylmethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, cellulose acetate hexahydro. Examples include phthalate, carboxymethylcellulose, ethylcellulose, methylcellulose and the like.

  Examples of the alkylene glycol polymer include addition polymers or addition copolymers such as ethylene glycol and propylene glycol.

  Examples of the urea polymer include those having methylol urea, dimethylol urea, ethylene urea or the like as a constituent component.

  Examples of the melamine polymer include those containing methoxymethylated melamine, methoxymethylated isobutoxymethylated melamine, methoxyethylated melamine and the like as constituent components.

  Further, water-soluble ones such as epoxy polymers and amide polymers can be used.

  Among them, it is preferable to include at least one selected from an alkylene glycol polymer, a cellulose polymer, a vinyl polymer, and an acrylic polymer, and in particular, pH adjustment is easy. The acrylic polymer is most preferable. Furthermore, a copolymer of an acrylic polymer and a water-soluble polymer other than the acrylic polymer can increase the shrinkage efficiency of the photoresist pattern interval while maintaining the shape of the photoresist pattern. It is preferable from the point. 1 type (s) or 2 or more types can be used for a water-soluble polymer.

  When the water-soluble polymer is used as a copolymer, the blending ratio of the constituent components is not particularly limited. However, if importance is placed on the stability over time, the blending ratio of the acrylic polymer is changed to other ratios. The amount is preferably larger than that of the constituent polymer. The improvement in stability over time can be solved by adding an acidic compound such as p-toluenesulfonic acid and dodecylbenzenesulfonic acid in addition to excessively adding the acrylic polymer as described above. is there.

  Particularly in the present invention, an acrylic polymer, a vinyl polymer and a copolymer are particularly preferably used in the combination with the heterocyclic compound described later, from the viewpoint of greatly improving the film shrinkage rate of the coating forming agent for pattern miniaturization. It is done. Further, as the acrylic polymer, those having one or more monomers selected from acrylic acid, methyl acrylate, methacrylic acid, and methyl methacrylate as constituent components are preferably used.

  The heterocyclic compound used in the present invention has at least an oxygen atom and / or a nitrogen atom. The heterocyclic compound is 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. Species are preferably used.

  Examples of the compound having an oxazolidine skeleton include substituted oxazolines represented by the following formula (I).

  Examples of the substituent include a hydrogen atom bonded to the carbon atom or nitrogen atom of the oxazoline represented by the above formula (I), which is a substituted or unsubstituted lower alkyl group having 1 to 6 carbon atoms, a carboxyl group, a hydroxyl group, a halogen atom. And compounds substituted with a 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.

  Examples of the compound having an oxazoline skeleton include 2-oxazoline represented by the following formula (II-1), 3-oxazoline represented by the formula (II-2), and 4-oxazoline represented by the formula (II-3). In addition to these, their 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 formulas (II-1) to (II-3) is substituted or unsubstituted with 1 to 6 carbon atoms. Examples thereof include compounds substituted with a substituted lower alkyl group, carboxyl group, hydroxyl group or 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 oxazoline skeleton, 2-methyl 2-oxazoline represented by the following formula (II-1-A) is preferably used.

  Examples of the compound having an oxazolidone skeleton include 5 (4) -oxazolone represented by the following formula (III-1), 5 (2) -oxazolone represented by the following formula (III-2), and the following formula (III- In addition to 4 (5) -oxazolone represented by 3), 2 (5) -oxazolone represented by the following formula (III-4), 2 (3) -oxazolone represented by the following formula (III-5), Substitutions are exemplified.

  As the substituent, a hydrogen atom bonded to a carbon atom or a nitrogen atom of a compound having an oxazolidone skeleton represented by the above formulas (III-1) to (III-5) is substituted or unsubstituted with 1 to 6 carbon atoms. Examples thereof include compounds substituted with a substituted lower alkyl group, carboxyl group, hydroxyl group or 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.

  Examples of the compound having an oxazolidinone skeleton (or a compound having a 2-oxazolidone skeleton) include oxazolidinone (or 2-oxazolidone) represented by the following formula (IV), and its substituted products. The

  As the substituent, a hydrogen atom bonded to a carbon atom or a nitrogen atom of the oxazolidinone (or 2-oxazolidone) represented by the above formula (IV) is a substituted or unsubstituted lower alkyl group having 1 to 6 carbon atoms, Examples thereof include compounds substituted with a carboxyl group, a hydroxyl group, and 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 formula (IV-1) is preferably used.

  In the present invention, by using a water-soluble polymer and a heterocyclic compound having at least an oxygen atom and / or a nitrogen atom as a coating refinement component for pattern miniaturization, the shrink amount (shrinkage rate) of the coating formation agent is reduced. Compared to the conventional case, the pattern can be significantly increased, and the pattern can be further miniaturized. According to the present invention, it is possible to increase the shrink amount of the pattern forming coating forming agent by about 20% or more compared to the case where the heterocyclic compound is not added.

  In the pattern refinement coating forming agent of the present invention, it is preferable to blend the above heterocyclic compound in a proportion of 1 to 50% by mass with respect to the water-soluble polymer, in particular from the viewpoint of increasing the amount of shrinkage. It is preferable to mix | blend in the ratio of -20 mass%.

  A water-soluble amine may be further added to the pattern forming coating forming agent. As the water-soluble amine, amines having a pKa (acid dissociation constant) of 7.5 to 13 in an aqueous solution at 25 ° C. are preferably used from the viewpoints of prevention of impurity generation, pH adjustment and the like. 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 triethylamine, 2-ethyl-hexylamine, dioctylamine, tributylamine, tripropylamine, triallylamine, heptylamine, cyclohexylamine; aromatic amines such as benzylamine and diphenylamine And cyclic amines such as piperazine, N-methyl-piperazine, methyl-piperazine, and hydroxyethylpiperazine. Among them, those having a boiling point of 140 ° C. or higher (760 mmHg) are preferable, and for example, monoethanolamine, triethanolamine and the like are preferably used.

  The water-soluble amine is preferably blended at a ratio of about 0.1 to 30% by mass, particularly about 2 to 15% by mass with respect to the pattern refinement coating-forming agent (solid content). If it is less than 0.1% by mass, the liquid may be deteriorated with time. On the other hand, if it exceeds 30% by mass, the shape of the photoresist pattern may be deteriorated.

  In addition, the coating forming agent for pattern miniaturization used in the present invention may further contain a non-amine-based water-soluble organic solvent as desired from the viewpoints of miniaturization of pattern dimensions, suppression of the occurrence of defects, and the like.

  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 derivatives thereof Is mentioned. Among them, polyhydric alcohols and derivatives thereof are preferable from the viewpoint of pattern size miniaturization and defect generation suppression, and glycerin is particularly preferable. One or more non-amine water-soluble organic solvents can be used.

  When the non-amine water-soluble organic solvent is blended, it is preferably blended at a ratio of about 0.1 to 30% by mass, particularly about 0.5 to 15% by mass with respect to the water-soluble polymer. If the amount is less than 0.1% by mass, the effect of reducing defects tends to be low, which is not preferable. If it exceeds 30% by mass, a mixing layer tends to be formed between the photoresist pattern.

  A surfactant can be added to the pattern forming coating forming agent, if desired, from the viewpoint of coating uniformity, in-plane uniformity, and the like.

  The surfactant is not particularly limited. However, when added to the water-soluble polymer, the surfactant has high solubility, does not generate suspension, and has compatibility with the polymer component. . By using a surfactant that satisfies these characteristics, the occurrence of defects, which has been related to the generation of bubbles (microfoam), especially when coating materials are applied, has been more effective. Can be prevented.

  From the above points, surfactants used in the present invention include N-alkylpyrrolidone surfactants, quaternary ammonium salt surfactants, and polyoxyethylene phosphate ester surfactants. At least one selected is preferably used.

  As the N-alkylpyrrolidone surfactant, the following general formula (V)

(Wherein R ₁ represents an alkyl group having 6 or more carbon atoms)
The thing represented by these is preferable.

  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-undecyl-2-pyrrolidone, N-dodecyl-2-pyrrolidone, N-tridecyl-2-pyrrolidone, N-tetradecyl-2-pyrrolidone, N-pentadecyl-2-pyrrolidone, N-hexadecyl -2-pyrrolidone, N-heptadecyl-2-pyrrolidone, N-octadecyl-2-pyrrolidone and the like. Among them, N-octyl-2-pyrrolidone (“SURFADONE LP100”; manufactured by ISP) is preferably used.

  As a quaternary ammonium salt surfactant, the following general formula (VI)

[Wherein, R ₂ , R ₃ , R ₄ and R ₅ each independently represents an alkyl group or a hydroxyalkyl group (provided that at least one of them represents an alkyl group or a hydroxyalkyl group having 6 or more carbon atoms) X ⁻ represents a hydroxide ion or a halogen ion]
The thing represented by these is preferable.

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

  As polyoxyethylene phosphate ester surfactants, the following general formula (VII)

[Wherein R ₆ represents an alkyl group having 1 to 10 carbon atoms or an alkylallyl group; R ₇ represents a hydrogen atom or (CH ₂ CH ₂ O) R ₆ (where R ₆ is as defined above) N represents an integer of 1 to 20]
Is preferred.

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

  When a surfactant is blended, it is preferably blended at a ratio of about 0.1 to 10% by weight, particularly about 0.2 to 2% by weight, based on the pattern forming coating forming agent (solid content). is there. By blending within the above range, it is thought that the causal relationship is deeply related to the variation in the shrinkage rate of the pattern accompanying the decrease in in-plane uniformity due to the deterioration of the coating property, or the bubbles generated at the time of coating called microfoam. Problems such as the occurrence of defects can be effectively prevented.

  The pattern forming coating forming agent used in the present invention is preferably used as an aqueous solution having a solid content concentration of 3 to 50% by mass, and particularly preferably used as an aqueous solution having a solid content concentration of 5 to 20% by mass. If the solid content concentration is less than 3% by mass, there is a risk of poor coating on the substrate. On the other hand, if it exceeds 50% by mass, an improvement in the effect commensurate with the increase in concentration is not observed, which is preferable from the viewpoint of handleability. Absent.

  In addition, although the coating formation agent for pattern refinement | miniaturization used for this invention is normally used as aqueous solution using water as a solvent as mentioned above, the mixed solvent of water and an alcohol solvent can also be used. Examples of the alcohol solvent include monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and isopropyl alcohol. These alcohol solvents are used by mixing with water at an upper limit of about 30% by mass.

  The coating forming agent for pattern miniaturization of the present invention has an effect of improving resolution to the extent that the resolution limit of a photoresist material is exceeded, and also corrects pattern variations in the substrate surface to improve in-plane uniformity. Furthermore, it is possible to correct a pattern shape disturbance (roughness) caused by reflected light from the substrate of exposure light, and to form a pattern with a good profile. Moreover, the shrink amount (shrinkage amount) of the coating forming agent (coating film) can be effectively increased, and a markedly improved pattern miniaturization effect can be obtained.

  In the fine pattern forming method according to the present invention, a substrate having a photoresist pattern is coated with the above-mentioned pattern refinement coating forming agent, and then heated to shrink the pattern refinement coating forming agent. A step of narrowing the interval between the photoresist patterns, and then removing the pattern forming coating forming agent. This removal step is particularly preferably a step of substantially completely removing the pattern refining coating forming agent. “Substantially completely removing” the pattern-reducing coating-forming agent means that the pattern pattern-reducing coating-forming agent is used to reduce the distance between the photoresist patterns using the shrinking action, and then to the interface with the photoresist pattern. This means that all of the pattern refinement coating forming agent is removed without leaving a significant thickness. Therefore, in this case, there is not included a method of making the pattern finer coating forming agent remain in the vicinity of the photoresist pattern interface to a certain thickness and miniaturizing the pattern by the remaining predetermined thickness.

  The production of a substrate having a photoresist 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 such as a chemical amplification type 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. Actinic rays such as laser light are irradiated through a desired mask pattern or drawn with an electron beam and then heated, and then heated with a developer such as 1 to 10% by mass of tetramethylammonium hydroxide (TMAH). A photoresist pattern can be formed on the substrate by developing with an alkaline aqueous solution such as an aqueous solution.

The photoresist composition used as the material for the photoresist pattern is not particularly limited, and is a photoresist composition for excimer lasers such as i, g-line photoresist compositions, KrF, ArF, F ₂ , and EB. Widely and generally used photoresist compositions such as (electron beam) photoresist compositions can be used.

a. Pattern Refinement Coating Forming Agent Application Step Next, the pattern refinement coating formation agent is applied and coated over the entire surface of the substrate having such a photoresist pattern as 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 above-mentioned pattern forming 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. Heating step Next, a heat treatment is performed to shrink the coating film made of the pattern refinement 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 spacing between the photoresist patterns defines the diameter and width of the pattern finally obtained. Therefore, the shrinkage of the coating film made of the above-mentioned coating refinement agent for pattern miniaturization causes the hole pattern diameter and the trench pattern to change. The width can be narrowed and the pattern can be miniaturized.

  The heating temperature is not particularly limited as long as it is a temperature capable of causing shrinkage of a coating film made of a pattern-reducing coating-forming agent, and is sufficient to perform pattern miniaturization. It is preferable to heat at a temperature that does not cause heat flow. The temperature at which the thermal flow does not occur in the photoresist pattern means that when a coating film formed of a pattern forming 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, Temperature that does not cause dimensional change due to spontaneous flow. The heat treatment at such a temperature makes it possible to more effectively form a fine pattern with a good profile, and particularly to the duty ratio (Duty) ratio in the wafer surface, that is, the pattern interval in the wafer surface. This is extremely effective in that the dependency can be reduced. Considering the softening point of various photoresist compositions used in the current photolithography technology, a preferable heat treatment is usually in the temperature range of about 80 to 160 ° C., but at a temperature that does not cause thermal flow in the photoresist. It is performed for about 90 seconds.

  Further, the thickness of the coating film made of the coating refinement agent for pattern miniaturization is preferably about the same as the height of the photoresist pattern or a height enough to cover it.

c. Pattern refinement coating forming agent removing step Thereafter, the coating film made of the pattern refinement coating forming agent remaining on the substrate having the photoresist pattern is washed with an aqueous solvent, preferably pure water, for 10 to 60 seconds. Remove. Prior to the removal by washing with water, a rinse treatment with an aqueous alkaline solution (for example, tetramethylammonium hydroxide (TMAH), choline, etc.) may be performed if desired. The pattern refinement 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 profile, and physical properties that can sufficiently satisfy the required required characteristics. It is a thing.

  The a. ~ C. The process may be repeated a plurality of times. Thus a. ~ C. By repeating the process 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 Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. The blending amount is mass% unless otherwise specified.

Example 1
3 g of a copolymer of polyacrylic acid / polyvinylpyrrolidone (AA / PVP) (AA: PVP = 2: 1 (polymerization ratio)), 0.27 g of triethanolamine, 0.30 g of 2-methyl-2-oxazoline, and polyoxy 0.03 g of “Plisurf A210G” (Daiichi Kogyo Seiyaku Co., Ltd.) as an ethylene phosphate ester surfactant was dissolved in 44 g of pure water to make the total solid content concentration about 7.5% by mass. A coating forming agent for pattern miniaturization was prepared.

  On the other hand, a positive photoresist “TDUR-P036 PM” (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated on the substrate and baked at 80 ° C. for 90 seconds to form a 0.48 μm-thick photoresist layer. .

  The photoresist layer is exposed using an exposure apparatus (“FPA-3000EX3”; manufactured by Canon Inc.), subjected to heat treatment at 120 ° C. for 90 seconds, and 2.38 mass% TMAH (tetramethylammonium). A photoresist pattern was formed by development using a hydroxide aqueous solution. By forming this photoresist pattern, a contact hole pattern having a pattern diameter of 184 nm (that is, the interval between the photoresist patterns is 184 nm) was obtained.

  Next, the coating-forming agent was applied onto the contact hole pattern, and heat treatment was performed at 116 ° C. for 60 seconds, so that the hole pattern was refined. Subsequently, the coating forming agent was removed using pure water at 23 ° C. The pattern diameter of the hole pattern at that time was 151 nm.

  Moreover, the in-plane uniformity of the coating film was good, and the variation in the flow rate could be suppressed. The profile of the pattern obtained was also good.

(Example 2)
3 g of a copolymer composed of polyacrylic acid / polyvinylpyrrolidone (AA / PVP) (AA: PVP = 2: 1 (polymerization ratio)), 0.27 g of triethanolamine, 0.30 g of 3-methyl-2-oxazolidone, and polyoxy 0.03 g of “Plisurf A210G” (Daiichi Kogyo Seiyaku Co., Ltd.) as an ethylene phosphate ester surfactant was dissolved in 44 g of pure water to make the total solid content concentration about 7.5% by mass. A coating forming agent for pattern miniaturization was prepared.

  Pattern refinement processing was performed in the same manner as in Example 1 except that the pattern refinement coating forming agent was used. At this time, the pattern diameter of the hole pattern was 157 nm.

  Moreover, the in-plane uniformity of the coating film was good, and the variation in the flow rate could be suppressed. The profile of the pattern obtained was also good.

(Comparative Example 1)
Polyacrylic acid / polyvinylpyrrolidone (AA / PVP) copolymer (AA: PVP = 2: 1 (polymerization ratio)) 3 g, triethanolamine 0.27 g, and polyoxyethylene phosphate ester surfactant 0.03 g of “Plysurf A210G” (Daiichi Kogyo Seiyaku Co., Ltd.) was dissolved in 41 g of pure water to prepare a coating forming agent for pattern miniaturization in which the total solid content concentration was about 7.5% by mass.

  Pattern refinement processing was performed in the same manner as in Example 1 except that the pattern refinement coating forming agent was used. At this time, the hole pattern had a pattern diameter of 162 nm.

  In addition, the in-plane uniformity of the coating film was good, and the variation in the flow rate was reduced. The profile of the pattern obtained was also good.

As described above, the coating forming agent for pattern miniaturization and the method for forming a fine pattern according to the present invention have a remarkably excellent pattern miniaturization effect, and are excellent in pattern dimension controllability, in a good profile and a semiconductor device. It is useful for forming fine patterns with required characteristics.

Claims (6)

A coating forming agent for pattern miniaturization coated on a substrate having a photoresist pattern (however, this coating forming agent for pattern miniaturization excludes those that cause a cross-linking reaction in the presence of an acid) , and heats the photoresist pattern. the coating formation agent and heat-shrunk by heat treatment at a temperature that does not cause flow, allowed narrowing the spacing between the photoresist patterns by utilizing the thermal shrinkage action, then substantially completely removing the coating formation agent A water-soluble polymer, a compound having an oxazolidine skeleton, a compound having an oxazoline skeleton, a compound having an oxazolidone skeleton, and an oxazolidinone skeleton Containing at least one heterocyclic compound selected from the compounds having For pattern fining coating formation agent.   The water-soluble polymer is at least selected from alkylene glycol polymers, cellulose derivatives, vinyl polymers, acrylic polymers, urea polymers, epoxy polymers, melamine polymers, and amide polymers. The coating formation agent for pattern refinement | miniaturization of Claim 1 which is 1 type.   The coating forming agent for pattern miniaturization according to claim 1 or 2, wherein the water-soluble polymer is at least one selected from an alkylene glycol polymer, a cellulose derivative, a vinyl polymer, and an acrylic polymer.   The coating forming agent for pattern miniaturization according to claim 1 or 2, wherein the water-soluble polymer is a copolymer comprising an acrylic monomer and a vinyl monomer as constituent components. The coating forming agent for pattern miniaturization according to any one of claims 1 to 4 , wherein the coating forming agent is an aqueous solution having a solid content concentration of 3 to 50% by mass.   The substrate having a photoresist pattern is coated with the coating forming agent for pattern miniaturization according to any one of claims 1 to 5, and then heated at a temperature that does not cause thermal flow in the photoresist pattern. A method of forming a fine pattern in which the coating forming agent for heat shrinks, the space between the photoresist patterns is narrowed by the heat shrinking action, and then the coating forming agent for pattern miniaturization is removed substantially completely.