Pattern formation method, developer for resist, and resist development method using the same

Abstract

To provide a pattern formation method in which unexposed resist composition does not easily remain on a substrate, a developer for resist, and a development method using the same.SOLUTION: A pattern formation method comprising a process for coating a resist composition containing metal oxide on a substrate to form a film, a process for exposing the resist composition film on the substrate, and a process for developing the resist composition film on the substrate after exposure using a developer for resist containing organic acid and organic solvent, is used.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to pattern formation using a resist composition containing a metal oxide. [Background technology]

[0002] In recent years, as the next generation of lithography technology, the use of short wavelength light sources is becoming more common due to the thinning of circuit patterns. It is necessary to expose the material to light using a short-wavelength light source such as extreme ultraviolet (EUV). The development of new resists for lithography using such short wavelength light sources is progressing. As a solution to this problem, pattern formation using a resist containing a metal oxide has been studied. In the development process of pattern formation using a resist containing a metal oxide, an organic solvent is used as a developer. It is described that it can be used as a [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 220835 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method described in Patent Document 1, the removal of the resist from the unexposed areas is insufficient in the development process. However, there is a problem that unexposed resist composition remains on the substrate. The purpose of this invention is to solve the above problems. [Means for solving the problem]

[0005] The present invention has the following aspects. [1] A process for forming a film by applying a resist composition containing a metal oxide to a substrate, and A step of exposing the resist composition film to light and a step of exposing the resist composition film to light using a resist developer containing an organic acid and an organic solvent. and developing the resist composition film on the substrate after the exposure to light. [2] The content of the organic acid in the resist developer is 0.03% by mass or more and 8% by mass or less. % or less. [3] The organic acid in the resist developer is a carboxylic acid, a sulfonic acid, a sulfinic acid, and at least one organic acid selected from the group consisting of phosphonic acid, phosphinic acid, and phosphonic acid. [1] or [2]. [4] The organic solvent in the resist developer is propylene glycol monomethyl ether butyl acetate, polypropylene glycol monomethyl ether and butyl acetate The pattern according to any one of [1] to [3], wherein the organic solvent is one or more selected from the group consisting of Method of forming the film. [5] The metal oxide is a metal oxide whose surface is modified with an organic acid. The pattern forming method according to any one of [4] to [7]. [6] A resist developer containing an organic solvent and an organic acid. [7] The content of the organic acid in the organic solvent is 0.01% by mass or more and 8% by mass or less. The resist developer according to [6] below. [8] The organic acid is a carboxylic acid, a sulfonic acid, a sulfinic acid, a phosphinic acid, or a phosphinic acid. The compound according to [6] or [7], which contains one or more organic acids selected from the group consisting of sulfonic acids. Developer for film. [9] The organic solvent is propylene glycol monomethyl ether acetate, polypropylene One member selected from the group consisting of propylene glycol monomethyl ether and butyl acetate The resist developer according to any one of [6] to [8], which contains the organic solvent described above.

[10] A method for developing a resist, using the developer according to any one of [6] to [9]. Effect of the Invention

[0006] According to the pattern forming method of the present invention, the resist composition in the unexposed area is effectively removed during development. The resist developer of the present invention contains an organic acid and an organic solvent, and therefore can remove unexposed resist. The composition can be effectively removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The pattern forming method of the present invention comprises applying a resist composition containing a metal oxide to a substrate to form a film. a step of exposing the resist composition film on the substrate to light; and a step of exposing the resist composition film on the substrate to light, the ... and developing the resist composition film on the substrate after exposure using a resist developer. In the present invention, a resist developer containing an organic acid and an organic solvent is used in the developing step. In this way, the unexposed resist composition can be efficiently removed.

[0008] <Step of applying a resist composition containing a metal oxide onto a substrate to form a film> In this process, a resist composition containing a metal oxide is applied to a substrate to form a film. The metal oxide is used for lithography using a short wavelength light source such as extreme ultraviolet (EUV) light. Known metal oxides such as those mentioned above can be used. Examples of the metal species of the metal oxide include titanium, zirconium, hafnium, vanadium, and the like. Zirconium, niobium, tantalum, molybdenum, tungsten, manganese, iron, ruthenium, cobalt Baltic, Rhodium, Iridium, Nickel, Palladium, Platinum, Copper, Zinc, Gallium, Iridium Examples of the metal include indium, germanium, tin, antimony, and bismuth. Among these, titanium, zirconium, hafnium, tungsten, zinc, gallium, Indium, tin, and bismuth are preferred, and zirconium, hafnium, indium, tungsten Sten, zinc, indium, tin, and bismuth are more preferable, and zirconium, hafnium, Zinc and tin are more preferred.

[0009] The metal oxide has a surface that is modified with an organic acid or the like, which improves resolution, roughness, In the present invention, the organic acid is an acid. It refers to an organic compound that exhibits the property of being polymerizable and has at least one carbon atom. The organic acid may be a carboxylic acid, a sulfonic acid, a sulfinic acid, a phosphinic acid, a phosphonic acid, or the like. Examples include phosphate.

[0010] Carboxylic acids include formic acid, acetic acid, oxalic acid, acrylic acid, methacrylic acid, and tiglic acid. , angelic acid, 2-methyl-3-butenoic acid, 4-pentenoic acid, trans-2,3-dimethyl Thiacrylic acid, benzoic acid, p-aminobenzoic acid, toluic acid, trifluoromethylbenzoic acid Benzoic acid, methoxybenzoic acid, trifluoromethoxybenzoic acid, pentanoic acid, hexanoic acid, Butanoic acid, octanoic acid (caprylic acid), nonanoic acid, decanoic acid, dodecanoic acid, 4-fluoro Examples include benzoic acid, anisic acid, naphthoic acid, and vinylbenzoic acid.

[0011] The sulfonic acid may be methanesulfonic acid, naphthalene-α-sulfonic acid, naphthalene -β-Sulfonic acid, vinyl sulfonic acid, benzenesulfonic acid, 4-chlorobenzenesulfone Acid, 3-nitrobenzenesulfonic acid, p-toluenesulfonic acid, p-xylene-2-sulfonic acid Examples include benzoic acid and the like.

[0012] The sulfinic acid may be benzenesulfinic acid, p-toluenesulfinic acid, 4- Examples thereof include vinylbenzenesulfinic acid and 1-naphthalenesulfinic acid.

[0013] The phosphinic acid may be phenylphosphinic acid, diphenylphosphinic acid, phenyl Examples thereof include vinylphosphinic acid and 1-hexylvinylphosphonic acid. Examples of the phosphonic acid include vinylphosphonic acid, methylphosphonic acid, and ethylphosphonic acid. phosphonic acid, t-butylphosphonic acid, cyclohexylphosphonic acid, phenylphosphonic acid, 4-butylphosphonic acid Examples thereof include bromophenylsulfonic acid and 2-phenylethylsulfonic acid.

[0014] From the viewpoint of dispersibility of metal oxide, carboxylic acid, sulfonic acid, and phosphonic acid are preferred. is most preferred. Two or more of these organic acids may be used in combination. In addition, whether the surface of the metal oxide of the present invention is modified with an organic acid or not can be confirmed by NMR. If the peaks detected by NMR can be assigned to organic acids, the gold It is determined that the surface of the metal oxide is modified with an organic acid.

[0015] The amount of the organic acid is 10 parts by mass per 100 parts by mass of the metal oxide. It is preferable that the content be 25 parts by mass or more and 25 parts by mass or less. If the amount of the organic acid is 10 parts by mass or more, the dispersibility is high, and if it is 25 parts by mass or less, In particular, from the viewpoint of dispersion stability, an amount of 13 parts by mass or more is more preferable. From the viewpoint of stability after application, the amount is preferably 23 parts by mass or less. The organic acid content is a value measured by thermogravimetric differential thermal analysis (TG-DTA). be.

[0016] The metal oxide can be produced by a method known in the art for producing metal oxides for resists. For example, chemical reactions such as hydrolysis and polycondensation of starting materials, mainly metal alkoxides and metal salts, When producing metal oxides by reaction, an organic acid is added to the reaction liquid, mixed, and dispersed. It can be manufactured.

[0017] The resist composition containing the metal oxide generally contains the metal oxide and an organic solvent. The organic solvent may be toluene, xylene, mesitylene, benzene, dichlorobenzene, aromatic hydrocarbons such as benzene, nitrobenzene; hexane, octane, cyclohexane, decahexane, Aliphatic hydrocarbons such as hydronaphthalene; acetone, methyl ethyl ketone, diethyl ketone , acetylacetone, methyl isobutyl ketone, cyclopentanone, cyclohexanone , N-methylpyrrolidone, and other ketones; formamide, N,N-dimethylformamide, Amides such as N,N-dimethylacetamide; diethyl ether, tetrahydrofuran, Ethers such as dioxane, methoxyethanol, ethoxyethanol; dichloromethane Chlorinated aliphatic hydrocarbons such as chloroform and 1,2-dichloroethane; methanol, ethanol Alcohols such as ethanol and isopropyl alcohol; ethyl acetate, butyl acetate, amine acetate Examples of the acetic acid ester include acetic acid esters such as ethyl ester.

[0018] These organic solvents may be used in combination of two or more kinds. The amount of the organic solvent is 80% by mass or more based on the total mass of the metal oxide and the organic solvent. It is preferably 85% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. The amount of the organic solvent is 99.7% by mass based on the total mass of the metal oxide and the organic solvent. The content is preferably 99.5% by mass or less, more preferably 99.5% by mass or less, and even more preferably 99% by mass or less. The resist composition of the present invention may further contain the organic acid. The amount of the organic acid contained in the composition is preferably 0.05% by mass or more and more preferably 30% by mass or more in terms of improving the dispersion stability. It is preferably less than % by mass.

[0019] Furthermore, the resist composition of the present invention contains additives such as an acid generator and a surfactant. The acid generator may be an onium salt compound, an N-sulfonyloxyimide compound, Examples of the surfactant include compounds containing halogens and diazoketone compounds. As an example of a component that has the effect of improving triation, etc., polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether Polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonyl Polyphenyl ether, polyethylene glycol dilaurate, polyethylene glycol di and nonionic surfactants such as stearates.

[0020] The resist composition is prepared by mixing a metal oxide, an organic solvent, an additive, and the like by a known method. It can be produced by mixing

[0021] The substrate may be a silicon wafer, a SiN wafer, an AlN wafer, or an aluminum-coated wafer. In addition, the adhesion of the resist composition and the resolution after development can be improved. To improve the reflection, an organic or inorganic anti-reflection film may be formed on the substrate.

[0022] The resist composition can be applied to a substrate by a known method such as spin coating, casting coating, roll coating, etc. Methods of knowledge can be used. The average thickness of the film to be formed is preferably 1 nm or more and 500 nm or less. The function of the resist film is impaired, and above the upper limit, the pattern after pattern formation and development This makes it easier for things to fall over.

[0023] If necessary, pre-baking may be performed after coating. The pre-baking temperature is 60° C. The pre-baking time is preferably 5 seconds or more and 300 seconds or less. stomach.

[0024] <Step of Exposing the Resist Composition Film on the Substrate> In this step, a mask having a predetermined pattern is applied to the resist composition film on the substrate obtained above. The light source used for exposure is ultraviolet, far ultraviolet, EUV, X-ray, gas. Examples include neutron rays. Among these, EUV and electron beams are the most popular because they generate secondary electrons from metal oxide particles. preferable.

[0025] <Step of developing the resist composition film on the substrate after exposure> In this step, the unexposed resist composition is developed with a resist developer containing an organic acid and an organic solvent. Remove and develop. The organic acid may be a carboxylic acid, a sulfonic acid, a sulfinic acid, a phosphinic acid, a phosphonic acid, or the like. Examples include phosphate.

[0026] Carboxylic acids include formic acid, acetic acid, oxalic acid, acrylic acid, methacrylic acid, and tiglic acid. , angelic acid, 2-methyl-3-butenoic acid, 4-pentenoic acid, trans-2,3-dimethyl Thiacrylic acid, benzoic acid, p-aminobenzoic acid, toluic acid, trifluoromethylbenzoic acid Benzoic acid, methoxybenzoic acid, trifluoromethoxybenzoic acid, pentanoic acid, hexanoic acid, Butanoic acid, octanoic acid (caprylic acid), nonanoic acid, decanoic acid, dodecanoic acid, 4-fluoro Examples include benzoic acid, anisic acid, naphthoic acid, and vinylbenzoic acid.

[0027] The sulfonic acid may be methanesulfonic acid, naphthalene-α-sulfonic acid, naphthalene -β-Sulfonic acid, vinyl sulfonic acid, benzenesulfonic acid, 4-chlorobenzenesulfone Acid, 3-nitrobenzenesulfonic acid, p-toluenesulfonic acid, p-xylene-2-sulfonic acid Examples include benzoic acid and the like.

[0028] The sulfinic acid may be benzenesulfinic acid, p-toluenesulfinic acid, 4- Examples thereof include vinylbenzenesulfinic acid and 1-naphthalenesulfinic acid.

[0029] The phosphinic acid may be phenylphosphinic acid, diphenylphosphinic acid, phenyl Examples thereof include vinylphosphinic acid and 1-hexylvinylphosphonic acid.

[0030] Examples of the phosphonic acid include vinylphosphonic acid, methylphosphonic acid, and ethylphosphonic acid. phosphonic acid, t-butylphosphonic acid, cyclohexylphosphonic acid, phenylphosphonic acid, 4-butylphosphonic acid bromophenylsulfonic acid, 2-phenylethylsulfonic acid, etc.

[0031] In terms of compatibility with metal oxides, carboxylic acids, sulfonic acids, and phosphonic acids are preferred. Acid is most preferred. Two or more of these organic acids may be used in combination. In addition, when the surface of the metal oxide in the resist is modified with the organic acid, In this case, the organic acid is preferably the same as the organic acid modifying the metal oxide.

[0032] The organic solvent may be an alcohol solvent, an ether solvent, a ketone solvent, an amide solvent, or the like. Examples of the solvent include ester-based solvents and hydrocarbon-based solvents. Alcohol-based solvents include isopropyl alcohol and 4-methyl-2-pentanol. aliphatic monoalcohol solvents having 1 to 18 carbon atoms, such as n-hexanol, cyclohexanol, etc. Alicyclic monoalcohol solvents with 3 to 18 carbon atoms, such as 1,2-propylene glycol Polyhydric alcohol solvents having 2 to 18 carbon atoms, such as propylene glycol monomethyl ether Examples of suitable solvents include polyhydric alcohol partial ether solvents having 3 to 19 carbon atoms, such as PGME.

[0033] Ether solvents include diethyl ether, dipropyl ether, and dibutyl ether. , dipentyl ether, diisoamyl ether, dihexyl ether, diheptyl ether Dialkyl ether solvents such as propylene glycol monomethyl ether (hereinafter referred to as P Polyhydric alcohol partial ether solvents such as tetrahydrofuran (sometimes written as GME), Furan, cyclic ether solvents such as tetrahydropyran, diphenyl ether, anisole and aromatic ring-containing ether solvents such as those mentioned above. Ketone solvents include acetone, methyl ethyl ketone, and methyl-n-propyl ketone. , methyl n-butyl ketone, diethyl ketone, methyl iSO-butyl ketone, 2-heptane Tanone, Ethyl n-butyl ketone, Methyl n-hexyl ketone, Di-isobutyl Ketones, trimethylnonanone and other chain ketone solvents, cyclopentanone, cyclohexanone Cyclic ketone solvents such as cyclohexane, cycloheptanone, cyclooctanone, and methylcyclohexanone Examples of solvents include 2,4-pentanedione, acetonylacetone, and acetophenone.

[0034] Amide solvents include N,N'-dimethylimidazolidinone and N-methylpyrrolidone. Cyclic amide solvents such as N-methylformamide, N,N'-dimethylformamide, N ,N'-Diethylformamide, acetamide, N-methylacetamide, N,N'-di Examples include chain amide solvents such as methylacetamide and N-methylpropionamide. .

[0035] Examples of ester solvents include monocarboxylic acid ester solvents such as butyl acetate and ethyl lactate. , propylene glycol acetate and other polyhydric alcohol carboxylate solvents, propylene PGMEA (Propylene glycol monomethyl ether acetate) ) and other polyhydric alcohol partial ether carboxylate solvents, and polyhydric Carbonate diester solvents, dimethyl carbonate, diethyl carbonate, etc. nate solvents, etc.

[0036] Examples of the hydrocarbon solvent include fatty acids having 5 to 12 carbon atoms, such as n-pentane and n-hexane. Aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents with carbon numbers of 5 to 16, such as toluene and xylene Examples include:

[0037] Among these, ester-based and ether-based solvents are preferred, and butyl acetate and propylene glycol are preferred. Propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether More preferred is propylene glycol (PGME). The content of the organic acid contained in the resist developer is such that the unexposed resist composition is removed. From this viewpoint, the content is preferably 0.01% by mass or more and 8% by mass or less, and more preferably 0.05% by mass or more and 4% by mass or less. It is more preferable that the content is % by mass or less.

[0038] The development may be carried out by a known method, and the substrate is placed in a tank filled with the resist developer. A method of immersing the resist developer on the substrate for a fixed period of time, in which the resist developer is piled up on the substrate surface by surface tension, A method of standing still for a fixed time, a method of spraying the resist developer onto the substrate surface, a method of rotating at a fixed speed The resist developer is discharged while scanning the nozzle at a constant speed onto the substrate on which the resist is being formed. Examples include the Act.

[0039] After development, the substrate may be rinsed and dried by a known method. A developer for use in the present invention may also be used. EXAMPLES

[0040] The present invention will be described below with reference to examples. The following description of the embodiments is merely illustrative, and the present invention will be described below with reference to the following examples. The present invention is not limited to the configuration of the embodiment shown below.

[0041] Example 1 <Metal oxide (zinc oxide, ZnO)> 150 mL of methanol and 0.90 g of potassium hydroxide are placed in a 300 mL three-neck flask. The mixture was placed in a flask, a reflux condenser was attached, and the mixture was heated to 60°C while stirring. Then, 1.8 g of zinc acetate was added. Drop 50 ml of methanol solution containing the hydrate and reflux for 2 hours at 60°C while stirring. Ta. After the reaction was completed, the solution was concentrated to 20 mL using an evaporator, and then added 100 mL of hexane. Add 20 mL of L,2-propanol, stir, leave at 4°C for 18 hours, and then centrifuge. The precipitate was collected. The precipitate was diluted with 20 ml of methanol, 10 ml of hexane, and 10 ml of isopropanol. After adding 0 and 20 mL of the mixture and allowing it to stand at 4°C for 6 hours, the mixture was centrifuged, and the precipitate was collected and dried. The amount of zinc oxide added was 0.5 g. A particle size measuring system (Otsuka Electronics Co., Ltd., " The mode diameter (most frequent diameter) of the particle size distribution measured using an ELSZ-2000 was 7 nm.

[0042] <Resist Composition> Propylene glycol monomethyl ether (P GME) 97 parts by weight, and as modifiers, p-toluic acid 0.9 parts by weight, acrylic acid 0.6 parts by weight The mixture was then washed with a tabletop ultrasonic cleaner (Honda Electronics Co., Ltd. W-113 MK-II). The frequency was continuously changed within the above range. ) and ultrasonic mixing for 60 minutes to obtain a resist composition.

[0043] <Step of applying resist composition to substrate to form film> A silicon wafer (conductivity type: P type, crystalline A resist composition was spin-coated onto the polished surface (orientation: (100), polished surface) (conditions: 1500 rpm, 6 After the substrate was prebaked at 100°C for 60 seconds, the resist on the substrate was The thickness of the composition film was measured using a film thickness measuring device (Mini-lab film-150 Lithotech The thickness was measured using a film thickness measuring device manufactured by Japan Film Co., Ltd., and this thickness was taken as the "film thickness before development."

[0044] <Creating evaluation samples> In order to evaluate the effect of removing the unexposed resist composition after development, the unexposed resist portion was The following samples were used as evaluation samples of the resist composition film having the above structure. The resist composition film on the substrate was allowed to stand in the air at room temperature for 5 hours. By such evaluation, it is possible to determine whether the resist composition film on the substrate is not exposed during the exposure process and whether the unexposed portion is The resist composition thus obtained is then subjected to a step of developing the resist composition film on the substrate after exposure. The effectiveness of removal can be evaluated by using the results.

[0045] <Step of developing the resist composition film on the substrate> Acrylic acid was used as the organic acid, and propylene glycol monomethyl ether was used as the organic solvent. Resist developer using tert-butyl acetate (PGMEA) containing 0.01% by weight of acrylic acid The liquid was obtained. The evaluation sample was immersed in the resist developer for 1 minute at room temperature to develop the resist. The evaluation sample was dried by blowing nitrogen at room temperature. The film thickness was measured using a film thickness measuring device (Mini-lab film-150 manufactured by LithoTech Japan). ) and the thickness was taken as the "film thickness after development."

[0046] <Evaluation> The amount of film thickness reduction was calculated from the film thickness before and after development using the following formula. If it is 30% or more, the unexposed resist composition is excellently removed. Film thickness reduction (%) = (1 - film thickness after development / film thickness before development) x 100

[0047] (Examples 2 to 11, Comparative Example 1) As shown in Table 1, the organic solvent and organic acid were changed to obtain a resist developer. Using the resist developer, the same evaluation as in Example 1 was carried out. The results are shown in Table 1.

[0048] [Table 1]

[0049] In the film thickness evaluation, "<10" means that the film thickness was measured using a film thickness measuring device (Mini-lab film- 150 Lithotech Japan) was at the detection limit of 10 nm. This means that: In Examples 1 to 11, the film thickness was reduced because the development was performed using a developer containing an organic solvent and an organic acid. The small amount was 30% or more, and good effects were obtained. On the other hand, in Comparative Example 1, the developer used contained only an organic solvent and did not contain an organic acid. Furthermore, the film thickness reduction after development was 6%, leaving room for improvement.

[0050] According to the pattern forming method of the present invention, development can be performed with a good film thickness reduction amount as described above. This improves the resolution of patterns on the substrate, allowing for finer patterns. It can be said that this can be achieved.

Claims

1. A pattern forming method comprising the steps of: applying a resist composition containing a metal oxide onto a substrate to form a film; exposing the resist composition film on the substrate to light; and developing the exposed resist composition film on the substrate using a resist developer containing an organic acid and an organic solvent.

2. 2. The pattern formation method according to claim 1, wherein the content of the organic acid in the resist developer is 0.01% by mass or more and 8% by mass or less.

3. A pattern formation method as described in claim 1, wherein the content of organic acid contained in the resist developer is 0.01 mass % or more and 4 mass % or less.

4. 3. The pattern formation method according to claim 1, wherein the organic acid in the resist developer is at least one organic acid selected from the group consisting of carboxylic acid, sulfonic acid, sulfinic acid, phosphinic acid, and phosphonic acid.

5. 2. The pattern formation method according to claim 1, wherein the organic solvent in the resist developer is at least one organic solvent selected from the group consisting of propylene glycol monomethyl ether acetate, polypropylene glycol monomethyl ether, and butyl acetate.

6. The pattern forming method according to claim 1, wherein the metal species of the metal oxide is selected from titanium, zirconium, hafnium, tungsten, zinc, gallium, indium, tin, and bismuth.

7. 2. The pattern formation method according to claim 1, wherein the metal oxide is a metal oxide whose surface is modified with an organic acid.

8. A resist developer comprising an organic solvent and an organic acid.

9. The resist developer according to claim 8 , wherein the content of the organic acid contained in the resist developer is 0.01% by mass or more and 8% by mass or less.

10. A resist developer as described in claim 8, wherein the content of organic acid contained in the resist developer is 0.01 mass % or more and 4 mass % or less.

11. 10. The resist developer according to claim 8, wherein the organic acid comprises at least one organic acid selected from the group consisting of carboxylic acid, sulfonic acid, sulfinic acid, phosphinic acid, and phosphonic acid.

12. 9. The resist developer according to claim 8, wherein the organic solvent comprises at least one organic solvent selected from the group consisting of propylene glycol monomethyl ether acetate, polypropylene glycol monomethyl ether, and butyl acetate.

13. A method for developing a resist using the developer according to claim 8.