Method for producing yttrium oxide-containing film

Abstract

This invention relates to a method for manufacturing a yttrium oxide-containing film by atomic layer deposition, comprising: introducing a raw material gas, formed by vaporizing a film-forming raw material containing yttrium dibutylcyclopentadienyl, into a processing environment to deposit yttrium dibutylcyclopentadienyl on a substrate; and reacting the yttrium dibutylcyclopentadienyl on the aforementioned substrate with a reactive gas containing a gas selected from the group consisting of oxygen plasma, ozone, ozone plasma, and mixtures thereof, in the processing environment to oxidize the yttrium.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a yttrium oxide-containing film by atomic layer deposition. [Previous Technology]

[0002] It is known that yttrium oxide film has high heat resistance, plasma resistance and light transmittance, and can be used as heat-resistant protective film, plasma-resistant protective film, optical film, etc.

[0003] Examples of methods for manufacturing the aforementioned thin films include sputtering, ion plating, coating thermal decomposition, and sol-gel methods, as well as MOD, CVD, and atomic layer deposition (ALD) methods, which are a type of CVD method. Among these, ALD is mainly used because it has many advantages such as excellent composition control and step coverage, suitability for mass production, and the ability to be mixed and integrated.

[0004] Patent document 1 discloses a method for manufacturing yttrium oxide film by ALD method, which uses tris(dibutylcyclopentadienyl)yttrium as film forming raw material and water vapor as reactive gas.

[0005] Patent document 2 discloses a method for manufacturing yttrium oxide film by CVD, which uses tris(dibutylcyclopentadienyl)yttrium as film forming raw material and oxygen as reactive gas.

[0006] Non-Patent Document 1 discloses a method for manufacturing yttrium oxide films using the ALD process, which uses tris(isopropylcyclopentadienyl)yttrium as a film-forming raw material and ozone as a reactive gas. [Prior Art Documents] [Patent Documents]

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-168398; Patent Document 2: Japanese Patent Application Publication No. 2008-274374; Non-Patent Document

[0008] Non-patent document 1: ECS Transactions, 50 (13) 107-116 (2012), @The Electrochemical Society, "Growth Characterstics and Properties of Yttrium Oxide Thin Films by Atomic Layer Deposition from Novel Y(iPrCp)3 Precursor and O3" [Summary of the Invention]

[0009] The problem that the invention is intended to solve

[0010] In the manufacture of yttrium oxide films by the ALD method, after the yttrium compound deposited on the substrate reacts with the reactive gas, the unreacted reactive gas and byproduct gas must be vented. However, in the method described in Patent Document 1, which uses water vapor as the reactive gas, there is a problem that the venting of water vapor is time-consuming. Furthermore, if it is desired to shorten the film formation cycle time and improve productivity under conditions of insufficient water vapor venting, carbon compounds originating from the byproduct gas remain in the obtained yttrium oxide film, resulting in problems such as not obtaining a high-quality film.

[0011] Furthermore, when oxygen is used as the reactive gas, the reaction between the film-forming material and the reactive gas must be carried out at a high temperature. In the manufacture of yttrium oxide film by CVD method using tributylcyclopentadienyl yttrium as the film-forming material and oxygen as the reactive gas, as described in Patent Document 2, oxygen at 400°C is used to react with tributylcyclopentadienyl yttrium at 600°C. However, due to the high temperature of the reaction, there is a significant problem of damage to the substrate. Furthermore, when the temperature is lowered to allow the material to react with oxygen, the reactivity of oxygen decreases, resulting in carbon residue in the yttrium oxide film.

[0012] Furthermore, as described in Non-Patent Document 1, when using tris(isopropylcyclopentadienyl)yttrium as a thin film forming material for the ALD method, since it is a solid compound at room temperature, it must be heated to become liquid before being introduced into the ALD device. In addition, in order to prevent tris(isopropylcyclopentadienyl)yttrium from solidifying, the entire piping of the ALD device must also be heated, which necessitates complex production management.

[0013] Therefore, the object of the present invention is to provide a method for manufacturing yttrium oxide films by the ALD process, which uses film-forming raw materials that do not require complex production management and can produce high-quality yttrium oxide films even with a shortened film formation cycle time. Means to solve the problem

[0014] The inventors have repeatedly and diligently reviewed the invention and discovered a method for manufacturing yttrium oxide films by means of the ALD method. This method uses film-forming raw materials that do not require complicated production management and can achieve both a significant reduction in film formation cycle time and the manufacture of high-quality yttrium oxide films. The invention was thus completed.

[0015] That is, the present invention relates to a method for manufacturing a yttrium oxide-containing film on a substrate by means of the ALD method, and provides a method for manufacturing a yttrium oxide-containing film, which includes: (A) step: introducing a raw material gas into a processing environment by vaporizing a film forming raw material containing yttrium dibutylcyclopentadienyl)yttrium, and depositing yttrium dibutylcyclopentadienyl)yttrium on the aforementioned substrate (hereinafter referred to as "(A) step"), and (B) step: reacting the yttrium dibutylcyclopentadienyl)yttrium deposited on the aforementioned substrate with a reactive gas containing a gas selected from the group consisting of oxygen plasma, ozone, ozone plasma and mixtures thereof in the processing environment to oxidize yttrium (hereinafter referred to as "(B) step").

[0016] In the manufacturing method of the present invention, the temperature of the substrate in step (B) is preferably in the range of 150°C to 400°C.

[0017] Furthermore, in the manufacturing method of the present invention, the pressure of the processing environment in step (B) when the reactive gas reacts with the yttrium (second butylcyclopentadienyl) deposited on the substrate is preferably in the range of 0.1 Pa to 10,000 Pa.

[0018] Furthermore, in the manufacturing method of the present invention, it is preferred that at least one of the steps between the aforementioned (A) step and the aforementioned (B) step, and after the aforementioned (B) step, is included, a step of venting the gas in the aforementioned processing environment.

[0019] Furthermore, in the manufacturing method of the present invention, it is preferable to repeat the film-forming cycle comprising steps (A) and (B) in sequence. Effects of the Invention

[0020] According to the present invention, since a film-forming raw material containing yttrium (dibutylcyclopentadienyl) containing liquid at room temperature is used, it is not necessary to heat the raw material and piping within the ALD device before it is introduced into the device. Furthermore, according to the present invention, since a reactive gas containing a gas selected from the group consisting of oxygen plasma, ozone, ozone plasma, and mixtures thereof is used, the time for the venting step after step (B) can be shortened compared to the case where water vapor is used as the reactive gas. Therefore, complex production management can be avoided, the film-forming cycle time can be significantly shortened, and high-quality yttrium oxide films with low residual carbon can be manufactured with good productivity.

Implementation Method

[0021] Form of implementing the invention

[0022] The manufacturing method of the present invention can use the same procedure as the well-known general ALD method, but the combination of step (A) and step (B) described below to manufacture the yttrium oxide film is a feature of the present invention.

[0023] Step (A) in the manufacturing method of the present invention involves introducing a raw material gas, formed by vaporizing a thin film forming raw material containing yttrium dibutylcyclopentadienyl (YDB), into a processing environment to deposit YDB onto a substrate. Here, "deposition" refers to the concept of adsorbing YDB onto a substrate. YDB is a liquid compound at room temperature, making it a compound with excellent operability. Therefore, by using a thin film forming raw material containing YDB, it is not necessary to heat the raw material before it is introduced into the ALD device or to install piping within the device, thus eliminating the need for complex production management and forming a yttrium oxide-containing film.

[0024] When the raw material gas containing the above-mentioned yttrium-containing yttrium film forming raw material is introduced into the film forming chamber (processing environment) of the ALD device, it is preferable that the raw material gas contains yttrium-containing ...

[0025] Here, the method for manufacturing yttrium (dibutylcyclopentadienyl) used in this invention is not particularly limited, and well-known reactions can be used to manufacture it. For example, it can be synthesized by salt exchange reaction of alkali metal complexes such as sodium dibutylcyclopentadienyl and potassium dibutylcyclopentadienyl with halides such as yttrium trichloride and tribromide.

[0026] In the method for manufacturing a yttrium oxide-containing film by the ALD method of the present invention, the film-forming raw material only needs to contain triterpenoid (dibutylcyclopentadienyl)yttrium as a precursor of the film, and its composition varies depending on the type of the desired film. For example, when manufacturing a film containing only yttrium as a metal, the film-forming raw material of the present invention does not contain metal compounds or half-metal compounds other than yttrium. On the other hand, when manufacturing a film containing yttrium and metals and / or half-metals other than yttrium, the film-forming raw material of the present invention may contain, in addition to triterpenoid (dibutylcyclopentadienyl)yttrium, compounds containing the desired metal and / or compounds containing half-metals (hereinafter referred to as "other precursors").

[0027] Furthermore, in the multi-component ALD process using multiple precursors, there are no particular restrictions on other precursors that can be used with tris(dibutylcyclopentadienyl)yttrium, and well-known general precursors that can be used as raw materials for thin film formation in the ALD process can be used.

[0028] Other precursors mentioned above may include, for example, compounds selected from the group consisting of compounds that use alcohols, diols, β-diketones, cyclopentadienes, and organic amines as organic ligands, one or more of which are compounds with silicon or metals. Furthermore, metal species that may be used as precursors include lithium, sodium, potassium, magnesium, calcium, strontium, barium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, osmium, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, aluminum, gallium, indium, germanium, lead, antimony, bismuth, radium, scandium, ruthenium, yttrium, lanthanum, cerium, tungsten, neodymium, beryllium, samarium, europium, thorium, tungsten, dysprosium, holmium, erbium, thorium, ytterbium, or ferruginium.

[0029] Examples of alcohol compounds used as organic ligands for the aforementioned other precursors include alkyl alcohols such as methanol, ethanol, propanol, isopropanol, butanol, dibutanol, isobutanol, terbutanol, pentanol, isopentanol, and terpentanol; 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-methoxy-1-methylethanol, 2-methoxy-1,1-dimethylethanol, 2-ethoxy-1,1-dimethylethanol, 2-isopropoxy-1,1-dimethylethanol, and 2-butoxy-1,1-dimethylethanol. - Ether alcohols such as dimethylethanol, 2-(2-methoxyethoxy)-1,1-dimethylethanol, 2-propoxy-1,1-diethylethanol, 2-dibutoxy-1,1-diethylethanol, and 3-methoxy-1,1-dimethylpropanol; dialkylamino alcohols such as dimethylaminoethanol, ethylmethylaminoethanol, diethylaminoethanol, dimethylamino-2-pentanol, ethylmethylamino-2-pentanol, dimethylamino-2-methyl-2-pentanol, ethylmethylamino-2-methyl-2-pentanol, and diethylamino-2-methyl-2-pentanol.

[0030] Examples of diol compounds used as organic ligands for the other precursors mentioned above include 1,2-ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,4-hexanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,3-butanediol, 2,4-butanediol, 2,2-diethyl-1,3-butanediol, 2-ethyl-2-butyl-1,3-propanediol, 2,4-pentanediol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 2,4-hexanediol, and 2,4-dimethyl-2,4-pentanediol.

[0031] Examples of β-diketone compounds used as organic ligands for the other precursors mentioned above include acetoacetone, hexane-2,4-dione, 5-methylhexane-2,4-dione, hepta-2,4-dione, 2-methylheptane-3,5-dione, 5-methylheptane-2,4-dione, 6-methylheptane-2,4-dione, 2,2-dimethylheptane-3,5-dione, 2,6-dimethylheptane-3,5-dione, 2,2,6-trimethylheptane-3,5-dione, 2,2,6,6-tetramethylheptane-3,5-dione, octane-2,4-dione, 2,2,6-trimethyloctane-3,5-dione, 2,6-dimethyloctane-3,5-dione, and 2,9-dimethylnonane-4,6-dione. Alkyl-substituted β-diones such as 2-methyl-6-ethyldecyl-3,5-dione and 2,2-dimethyl-6-ethyldecyl-3,5-dione; fluorinated alkyl β-diones such as 1,1,1-trifluoropentane-2,4-dione, 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione, 1,1,1,5,5,5-hexafluoropentane-2,4-dione and 1,3-diperfluorohexylpropyl-1,3-dione; and ether-substituted β-diones such as 1,1,5,5-tetramethyl-1-methoxyhexane-2,4-dione, 2,2,6,6-tetramethyl-1-methoxyheptane-3,5-dione and 2,2,6,6-tetramethyl-1-(2-methoxyethoxy)heptane-3,5-dione.

[0032] Examples of cyclopentadiene compounds used as organic ligands for the aforementioned other precursors include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, isopropylcyclopentadiene, butylcyclopentadiene, dibutylcyclopentadiene, isobutylcyclopentadiene, tributylcyclopentadiene, dimethylcyclopentadiene, tetramethylcyclopentadiene, and pentamethylcyclopentadiene. Examples of organic amine compounds used as organic ligands for the aforementioned organic ligands include methylamine, ethylamine, propylamine, isopropylamine, butylamine, dibutylamine, tributylamine, isobutylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, ethylmethylamine, propylmethylamine, and isopropylmethylamine.

[0033] The aforementioned other precursors are well known in the art, and their manufacturing methods are also well known. For example, when using an alcohol compound as an organic ligand, the precursor can be produced by reacting an inorganic salt of the aforementioned metal or its hydrate with an alkali metal alkoxide of the alcohol compound. Here, examples of inorganic salts of metals or their hydrates include metal halides and nitrates, and examples of alkali metal alkoxides include sodium alkoxides, lithium alkoxides, and potassium alkoxides.

[0034] Furthermore, in the multi-component ALD method described above, there are methods for vaporizing and supplying thin film forming raw materials independently of each component (hereinafter also referred to as "single-source method"), and methods for vaporizing and supplying mixed raw materials that are mixed with the desired composition in advance (hereinafter also referred to as "mixed-source method").

[0035] In the case of a single-source method, the other precursors mentioned above are preferably compounds that exhibit behavior similar to thermal and / or oxidative decomposition of tris(dibutylcyclopentadienyl)yttrium. In the case of a mixed-source method, the other precursors mentioned above are preferably compounds that, in addition to those exhibiting behavior similar to thermal and / or oxidative decomposition of tris(dibutylcyclopentadienyl)yttrium, do not deteriorate due to chemical reactions during mixing.

[0036] Furthermore, in the case of the mixed source method, a mixture of tris(dibutylcyclopentadienyl)yttrium and other precursors or a mixed solution in which the mixture is dissolved in an organic solvent can be used as a film forming raw material.

[0037] There are no particular limitations on the organic solvents used, and commonly known organic solvents can be used. Examples of such organic solvents include acetate esters such as ethyl acetate, butyl acetate, and methoxyethyl acetate; ethers such as tetrahydrofuran, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, dibutyl ether, and dialkyl; ketones such as methyl butyl ketone, methyl isobutyl ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone, methyl pentyl ketone, cyclohexanone, and methyl cyclohexanone; and hexane, cyclohexane, and cyclohexane. Hydrocarbons such as hexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, heptane, octane, toluene, and xylene; hydrocarbons containing cyano groups such as 1-cyanopropane, 1-cyanobutane, 1-cyanohexane, cyanocyclohexane, cyanobenzene, 1,3-dicyanopropane, 1,4-dicyanobutane, 1,6-dicyanohexane, 1,4-dicyanocyclohexane, and 1,4-dicyanobenzene; and pyridine, dimethylpyridine, etc. These organic solvents can be used alone or in mixtures of two or more, depending on the solubility of the solute, the operating temperature, boiling point, and ignition point.

[0038] In the manufacturing method of the present invention, when a solution containing yttrium (dibutylcyclopentadienyl) and an organic solvent is used as the thin film forming raw material, it is preferable to add an organic solvent in such a way that the total amount of the precursor in the thin film forming raw material is 0.01 mol / L to 2.0 mol / L, especially 0.05 mol / L to 1.0 mol / L.

[0039] Here, the total amount of the precursors, when the film forming raw materials do not contain metal compounds and half-metal compounds other than yttrium, is the total amount of tris(dibutylcyclopentadienyl)yttrium and other precursors containing yttrium; when the film forming raw materials contain other precursors besides tris(dibutylcyclopentadienyl)yttrium, it is the total amount of tris(dibutylcyclopentadienyl)yttrium and other precursors.

[0040] Furthermore, the above-mentioned film-forming raw materials may contain nucleophilic reagents as needed to improve the stability of tributylcyclopentadienyl yttrium and other precursors. Examples of such nucleophilic reagents include, for instance, ethylene glycol ethers such as glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether; crown ethers such as 18-crown ether-6, dicyclohexyl-18-crown ether-6, 24-crown ether-8, dicyclohexyl-24-crown ether-8, and dibenzo-24-crown ether-8; ethylenediamine; N,N'-tetramethylethylenediamine; diethylenetriamine; triethylenetetramine; diethylenepentamine; pentaethylenehexamine; 1,1,4,7,7-pentamethyldiethylenetriamine; and 1,1,4,7,10,10-hexamethyltriethylenetetramine. Polyamines such as triethoxytriethylamine, cyclic polyamines such as tetraazacyclotetradecane and tetraazacyclododecane, heterocyclic compounds such as pyridine, pyrrolidine, piperidine, morpholine, N-methylpyrrolidine, N-methylpiperidine, N-methylmorpholine, tetrahydrofuran, tetrahydrofuran, 1,4-diane, acetazole, thiazole, oxothiacyclopentane, β-keto esters such as methyl acetate, ethyl acetate, 2-methoxyethyl acetate, or β-diketones such as acetoacetone, 2,4-hexanedione, 2,4-heptanedione, 3,5-heptanedione, and dipentylmethane. The amount of these nucleophilic reagents used is preferably 0.1 mol to 10 mol relative to the total amount of the precursor, more preferably 1 mol to 4 mol.

[0041] The thin film forming raw materials used in the manufacturing method of the present invention should preferably be free of impurity metal elements, impurity halogens such as chlorine, and impurity organic components other than those constituting the raw materials. The amount of impurity metal elements is preferably 100 ppb or less per element, more preferably 10 ppb or less, and the total amount is preferably 1 ppm or less, more preferably 100 ppb or less. Especially when used as gate insulating films, gate films, or barrier layers for LSIs, the content of alkali metal elements and alkaline earth metal elements that affect the electrical properties of the resulting thin film must be reduced. The amount of impurity halogens is preferably 100 ppm or less, more preferably 10 ppm or less, and even more preferably 1 ppm or less. The total amount of impurity organic components is preferably 500 ppm or less, more preferably 50 ppm or less, and even more preferably 10 ppm or less. Furthermore, since moisture is a cause of particle generation in the thin film forming raw materials and during thin film formation, it is advisable to remove moisture from precursors, organic solvents, and nucleophilic reagents as much as possible before use to reduce their respective moisture content. The water content of the precursor, organic solvent and nucleophilic reagent is preferably less than 10 ppm, and more preferably less than 1 ppm.

[0042] Furthermore, in the manufacturing method of the present invention, the raw materials for forming the thin film are preferably as free of particles as possible in order to reduce or prevent particulate contamination of the formed thin film. Specifically, in the particle measurement by a light scattering liquid particle detector in the liquid phase, the number of particles larger than 0.3 μm is preferably 100 or less in 1 ml of liquid phase, and the number of particles larger than 0.2 μm is more preferably 100 or less in 1 ml of liquid phase.

[0043] As an apparatus for the method of manufacturing the yttrium oxide-containing film of the present invention using the thin film forming raw material as described above, a well-known ALD apparatus can be used. Examples of specific apparatuses include the apparatus shown in Figures 1 and 3 that can bubble and supply the precursor, and the apparatus shown in Figures 2 and 4 that has a vaporization chamber. Also, the apparatus shown in Figures 3 and 4 that can perform plasma treatment on reactive gases can be used. Not limited to the single-sheet apparatus with a film-forming chamber shown in Figures 1 to 4, an apparatus employing a batch furnace that can process multiple sheets simultaneously can also be used.

[0044] In the manufacturing method of the present invention, as a method for introducing the raw material gas into the processing environment in step (A) by heating and / or depressurizing the container storing the raw material for thin film formation in the ALD method (hereinafter referred to as the "raw material container") to vaporize it into vapor, and then introducing it into the film forming chamber (processing environment) where the substrate is provided, together with a carrier gas such as argon, nitrogen, or helium, as needed. Alternatively, the raw material for thin film formation can be transported to the vaporization chamber in a liquid or solution state, and vaporized into vapor by heating and / or depressurizing it in the vaporization chamber, and then the vapor can be introduced into the film forming chamber.

[0045] In the case of gas delivery method, yttrium (dibutylcyclopentadienyl) itself can be used as a film forming material. In the case of liquid delivery method, since yttrium (dibutylcyclopentadienyl) is a liquid at room temperature, it can be used directly as a film forming material, but a solution containing yttrium (dibutylcyclopentadienyl) and an organic solvent can be used as a film forming material.

[0046] In the manufacturing method of the present invention, the method for vaporizing the thin film forming raw material containing tris(dibutylcyclopentadienyl)yttrium in step (A) is not particularly limited, and can be carried out by a vaporization method of organometallic compounds used in the well-known general ALD process. For example, it can be vaporized by heating and / or depressurizing in the raw material container of the ALD device shown in FIG1.

[0047] The substrate material disposed in the above-mentioned film-forming chamber may be, for example, silicon; ceramics such as indium arsenide, indium gallium arsenide, silicon oxide, silicon nitride, boron nitride, silicon carbide, aluminum oxide, aluminum nitride, tantalum oxide, tantalum nitride, titanium oxide, titanium nitride, titanium carbide, ruthenium oxide, zirconium oxide, hafnium oxide, lanthanum oxide, and gallium nitride; glass; platinum, ruthenium, aluminum, copper, nickel, cobalt, tungsten, molybdenum, stainless steel, or alloys thereof. Furthermore, the surface of the substrate may be coated.

[0048] The shape of the matrix can be plate-like, spherical, fibrous, scaly, or particle-like (especially microparticles). The surface of the matrix can be planar or a three-dimensional structure such as a groove structure.

[0049] Step (B) in the manufacturing method of the present invention is a step of oxidizing yttrium by reacting the yttrium deposited on the substrate with a reactive gas containing a group of gases selected from oxygen plasma, ozone, ozone plasma and mixtures thereof in a processing environment.

[0050] The reactive gas in this step contains a gas selected from the group consisting of oxygen plasma, ozone, ozone plasma, and mixtures thereof. Since the reactive gas uses such a gas, it is easier to exhaust it from the treatment environment compared to the case containing water vapor, thus shortening the time required for the exhaust step.

[0051] Furthermore, the aforementioned reactive gas system can be generated outside the film-forming chamber and introduced into the film-forming chamber. The ALD apparatus shown in Figures 3 and 4 can be used to plasmaize oxygen or ozone gas in the film-forming chamber. There are no particular limitations on the method of generating oxygen plasma, ozone, and ozone plasma, or the method of introducing them into the film-forming chamber; methods commonly used in ALD processes can be used.

[0052] The aforementioned reactive gas may be a single gas or a mixture of gases such as argon, nitrogen, oxygen, and hydrogen. In the case of a mixture, the concentration of the gas selected from the group consisting of oxygen plasma, ozone, ozone plasma, and mixtures thereof is preferably in the range of 0.01 vol% to 50 vol%, more preferably 0.1 vol% to 20 vol%, and even more preferably 1.0 vol% to 15 vol%.

[0053] Furthermore, in step (B), the water content of the reactive gas is preferably less than 0.1% by mass, and more preferably less than 0.01% by mass.

[0054] The yttrium oxide film obtained by the manufacturing method of the present invention can be any thin film containing 5% by mass or more of yttrium oxide, such as yttrium oxide, yttrium oxide-stabilized zirconium oxide, yttrium orthovanadate, yttrium sulfide dioxide, yttrium-barium-copper oxide, yttrium aluminate, etc. Among these, the manufacturing method of the present invention is more suitable as a method for manufacturing yttrium oxide films.

[0055] For example, a method for manufacturing a yttrium oxide-containing film on a silicon substrate by means of the manufacturing method of the present invention will be described. Here, the ALD apparatus shown in FIG1 is used.

[0056] First, a silicon substrate is placed in the film-forming chamber. There is no particular limitation on the method of placing the silicon substrate; any known general method can be used. Next, yttrium (dibutylcyclopentadienyl) is vaporized in the feed container. The temperature of the feed container is preferably in the range of 20°C to 200°C. Then, the feed gas containing the vaporized yttrium (dibutylcyclopentadienyl) is introduced into the film-forming chamber, preferably deposited (adsorbed) on a silicon substrate heated to 20°C to 400°C, more preferably 150°C to 250°C (step (A)).

[0057] Furthermore, in step (A), the pressure in the film-forming chamber when introducing the (second butylcyclopentadienyl) yttrium into the film-forming chamber is in the range of 0.1 Pa to 10,000 Pa, more preferably 1 Pa to 1,000 Pa, and even more preferably 10 Pa to 500 Pa.

[0058] Next, the yttrium (dibutylcyclopentadienyl) that has not been deposited on the silicon substrate is vented from the film-forming chamber (venting step 1). While it is ideal to completely vent the yttrium (dibutylcyclopentadienyl) that has not been deposited on the silicon substrate from the film-forming chamber, complete venting is not necessarily required. As a venting method, methods such as flushing the system with inert gases such as helium or argon, depressurizing the system and venting, or a combination of these methods are possible. The depressurization rate is preferably 0.01 Pa to 300 Pa, more preferably 0.1 Pa to 150 Pa.

[0059] Next, yttrium (dibutylcyclopentadienyl)-yttrium deposited on a silicon substrate is reacted in a film-forming chamber with a reactive gas containing a gas selected from oxygen plasma, ozone, ozone plasma, and mixtures thereof, thereby oxidizing the yttrium (step (B)). In this step, the substrate temperature during thermal action is preferably in the range of 150°C to 400°C, more preferably in the range of 150°C to 300°C, and even more preferably in the range of 150°C to 250°C, to obtain the vapor of yttrium (dibutylcyclopentadienyl)-yttrium. The difference between the substrate temperature in step (A) and the substrate temperature during thermal action in step (B), expressed in absolute value, is preferably in the range of 0°C to 20°C. This is because by adjusting to this range, the warping of the yttrium oxide film is less likely to occur. However, even if the substrate temperature does not reach 150°C, a yttrium oxide film derived from tris(dibutylcyclopentadienyl)yttrium may still be formed.

[0060] The pressure of the processing environment during the reaction of the reactive gas with yttrium (dibutylcyclopentadienyl) in step (B) above is in the range of 0.1 Pa to 10,000 Pa, preferably 1 Pa to 1,000 Pa, and more preferably 10 Pa to 500 Pa. By adjusting to this range, a high-quality thin film free of residual carbon can be obtained.

[0061] Next, the unreacted reactive gas and byproduct gas are vented from the film-forming chamber (venting step 2). Ideally, the unreacted reactive gas and byproduct gas should be completely vented from the film-forming chamber, but complete venting is not always necessary. Venting methods may include flushing the system with inert gases such as helium or argon, venting the system by depressurizing, or a combination of these methods. The depressurization rate is preferably 0.01 Pa to 300 Pa, more preferably 0.1 Pa to 150 Pa.

[0062] The series of operations consisting of step (A), exhaust step 1, step (B) and exhaust step 2 as described above is treated as a cycle, and the cycle is repeated multiple times until the desired yttrium oxide film thickness is obtained.

[0063] Furthermore, in the manufacturing method of the present invention, energy such as plasma, light, and voltage may be further applied. There is no particular limitation on the timing of applying such energy; for example, it may be applied when the yttrium (second butylcyclopentadienyl) is vaporized and introduced into the film-forming chamber in step (A), or when the system is vented in the venting step, or between the aforementioned steps.

[0064] In the manufacturing method of the present invention, after thin film deposition, in order to obtain a better film quality, annealing can be performed in an inert gas environment or a reducing gas environment. In cases requiring stepped filling, a reflux step can also be included. The temperature in this case is 400℃~1200℃, preferably 500℃~800℃. Example

[0065] Hereinafter, the present invention will be described in more detail by way of examples and comparative examples. However, the present invention is not limited to the following examples, etc.

[0066] [Example 1] As a raw material for thin film formation, yttrium oxide (Y-5000) was fabricated on a silicon wafer using a yttrium oxide (Y-2, butylcyclopentadienyl) yttrium (manufactured by ADEKA Corporation, product name "Y-5000") and the ALD apparatus shown in FIG1 under the ALD conditions described below. The composition of the resulting thin film was confirmed by X-ray photoelectron spectroscopy, and the resulting thin film was yttrium oxide with no detectable residual carbon. The time required for one cycle of any one of steps (1) to (4) was 25.2 seconds.

[0067] (ALD process conditions) Reaction temperature (silicon wafer temperature): 200℃ Reactive gas: ozone The series of steps (1) to (4) below are treated as 1 cycle and repeated for 50 cycles. (1) The film forming material (hereinafter referred to as "raw material gas") that has been vaporized under the conditions of raw material container temperature: 180℃ and raw material container pressure: 100Pa is introduced into the film forming chamber and deposited for 5 seconds at system pressure: 100Pa. (2) The undeposited raw material gas is removed by 10 seconds of argon flushing. (3) The reactive gas is introduced into the film forming chamber and reacted for 0.2 seconds at system pressure: 100Pa. (4) The unreacted reactive gas and by-product gas are removed by 10 seconds of argon flushing.

[0068] [Comparative Example 1] Except that the reactive gas was changed to water vapor, a yttrium oxide film was manufactured by the same method as in Example 1. The composition of the resulting film was confirmed by X-ray photoelectron spectroscopy, and the film was found to be yttrium oxide with a residual carbon content of 1.8% by mass. The time required for one cycle of any one of steps (1) to (4) was 25.2 seconds.

[0069] [Comparative Example 2] Except for changing the film forming raw material from tris(dibutylcyclopentadienyl)yttrium to tris(isopropylcyclopentadienyl)yttrium, the same method as in Comparative Example 1 was used to manufacture a yttrium oxide film. The composition of the resulting film was confirmed by X-ray photoelectron spectrometry, and the resulting film was yttrium oxide with a residual carbon content of 5.6% by mass. The time required for one cycle of any one of steps (1) to (4) was 25.2 seconds.

[0070] [Comparative Example 3] Except that the reactive gas was changed to oxygen, a yttrium oxide film was manufactured by the same method as in Example 1. The composition of the resulting film was confirmed by X-ray photoelectron spectroscopy, and the film was found to be yttrium oxide with a residual carbon content of 0.8% by mass. The time required for one cycle of any one of steps (1) to (4) was 25.2 seconds.

[0071] [Comparative Example 4] Except that the argon purging time in step (4) was changed from 10 seconds to 60 seconds, the same method as in Comparative Example 1 was used to manufacture a yttrium oxide film. The composition of the resulting film was confirmed by X-ray photoelectron spectroscopy, and the film was found to be yttrium oxide with no residual carbon. The time required for one cycle of any one of steps (1) to (4) was 75.2 seconds.

[0072] [Comparative Example 5] Except that the argon purging time in step (2) was changed from 10 seconds to 30 seconds, the same method as in Comparative Example 4 was used to manufacture a yttrium oxide film. The composition of the resulting film was confirmed by X-ray photoelectron spectroscopy, and the film was found to be yttrium oxide with no residual carbon. The time required for one cycle of any one of steps (1) to (4) was 95.2 seconds.

[0073]

[0074] As can be seen from Comparative Example 1, when the reactive gas is water vapor, a rinsing time of 10 seconds is insufficient, and residual carbon is detected in the yttrium oxide-containing film, making it impossible to produce a high-quality film. Furthermore, as can be seen from Comparative Example 2, when using tris(isopropylcyclopentadienyl)yttrium as the film-forming raw material, when the reactive gas is water vapor, a rinsing time of 10 seconds is insufficient, and residual carbon is detected in the yttrium oxide-containing film, making it impossible to produce a high-quality film.

[0075] In Comparative Examples 4 and 5, when yttrium triterpenoid (dibutylcyclopentadienyl) was used as the raw material for film formation, even when water vapor was used as the reactive gas and argon purging time was sufficiently ensured, no residual carbon was detected in the resulting film. However, due to the long cycle time, the productivity of yttrium oxide films could not be met.

[0076] In contrast to these, it can be confirmed from Example 1 that when using tris(dibutylcyclopentadienyl)yttrium as the film forming raw material and using a gas selected from the group consisting of oxygen plasma, ozone, ozone plasma and mixtures thereof as the reactive gas, the productivity is improved by the ALD method when manufacturing yttrium oxide films due to the significant reduction in cycle time, and high-quality yttrium oxide films with no detectable residual carbon can be manufactured. [Simplified Explanation of the Diagram]

[0077] [Figure 1] is a schematic diagram showing an example of an ALD apparatus used in the method for manufacturing a yttrium oxide-containing film of the present invention. [Figure 2] is a schematic diagram showing another example of an ALD apparatus used in the method for manufacturing a yttrium oxide-containing film of the present invention. [Figure 3] is a schematic diagram showing yet another example of an ALD apparatus used in the method for manufacturing a yttrium oxide-containing film of the present invention. [Figure 4] is a schematic diagram showing yet another example of an ALD apparatus used in the method for manufacturing a yttrium oxide-containing film of the present invention.

Claims

1. A method for manufacturing a yttrium oxide-containing film by atomic layer deposition, comprising: (A) a step of introducing a feed gas, which is formed by vaporizing a film-forming raw material containing yttrium dibutylcyclopentadienyl, into a processing environment, and depositing yttrium dibutylcyclopentadienyl on a substrate; and (B) a step of reacting the yttrium dibutylcyclopentadienyl deposited on the substrate with a reactive gas containing a gas selected from the group consisting of oxygen plasma, ozone, ozone plasma, and mixtures thereof, in the processing environment to oxidize the yttrium, wherein the content of the yttrium dibutylcyclopentadienyl is 99% by volume or more, and the amount of water vapor contained in the reactive gas is 0.01% by mass or less.

2. The method for manufacturing a yttrium oxide film as claimed in claim 1, wherein the temperature of the substrate in step (B) is in the range of 150°C to 400°C.

3. The method for manufacturing a yttrium oxide film as claimed in claim 1, wherein the pressure of the processing environment in step (B) above, during which the yttrium (dibutylcyclopentadienyl) deposited on the aforementioned substrate reacts with the reactive gas, is in the range of 0.1 Pa to 10,000 Pa.

4. A method for manufacturing a yttrium oxide film according to any one of claims 1 to 3, wherein at least one of the steps between step (A) and step (B) and after step (B) is included, a step of venting the gas in the aforementioned treatment environment.

5. A method for manufacturing a yttrium oxide film as claimed in any of claims 1 to 3, wherein a film-forming cycle comprising the aforementioned step (A) and the aforementioned step (B) is repeated sequentially.

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