Raw material for forming thin film by atomic layer deposition method, thin film, method for manufacturing thin film, and ruthenium compound
Patent Information
- Authority / Receiving Office
- TW · TW
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2022-11-16
- Publication Date
- 2023-09-16
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Abstract
Description
[Technical Field]
[0002] This invention relates to a raw material for thin film formation by atomic layer deposition containing a specific ruthenium compound, a method for manufacturing a thin film using the raw material for thin film formation by atomic layer deposition, the thin film, and the ruthenium compound. [Previous Technology]
[0003] Ruthenium is a metal with low electrical resistance and stable thermal and chemical properties. Thin films containing ruthenium atoms (hereinafter sometimes referred to as "ruthenium-containing thin films") exhibit unique electrical properties and are used in various applications. They are known to be used as electrode materials, wiring materials, resistive films, antimagnetic films for recording layers of hard disks, catalyst materials for solid polymer fuel cells, and metal gate materials for MOS-FETs, etc.
[0004] Examples of methods for manufacturing ruthenium-containing thin films include sputtering, ion plating, coating pyrolysis, MOD (Metal-on-Deposition) and chemical vapor deposition (CVD) methods such as sol-gel methods. Among these, CVD is the most suitable manufacturing process due to its advantages such as excellent composition control, step coverage, suitability for mass production, and hybrid integration.
[0005] Various raw materials that can be used in chemical vapor deposition methods such as CVD and ALD have been reported, but the temperature range known as the ALD window must be sufficiently wide for raw materials suitable for ALD thin film formation. It is common knowledge in this field that even raw materials suitable for CVD thin film formation are not suitable for ALD.
[0006] Various compounds are known as raw materials for forming ruthenium-containing thin films. For example, Patent Document 1 discloses a ruthenium complex coordinated with cyclohexadiene. Patent Document 2 discloses a ruthenium compound consisting of two six-membered rings comprising two carbonyl groups, a ruthenium atom, and a ketimine group. Patent Document 3 discloses a ruthenium-containing thin film manufactured by thermal CVD using a mixture of ruthenium complexes and a reducing gas. Non-Patent Document 1 discloses a ruthenium complex having two carbonyl groups and two five-membered rings bonded to a ketimine group. [Prior Art Documents] [Patent Documents]
[0007] [Patent Document 1] International Publication No. 2008 / 078296 [Patent Document 2] International Publication No. 2015 / 093177 [Patent Document 3] Japanese Patent Application Publication No. 2014-118605 [Non-Patent Documents]
[0008] [Non-patent document 1] Chemistry of Materials (2003), 15(12), 2454-2462, "Synthesis and Characterization of Ruthenium Complexes with Two Fluorinated Amino Alkoxide Chelates. The Quest To Design Suitable MOCVD Source Reagents" [Summary of the Invention]
[0009] [The problem the invention aims to solve]
[0010] However, when using the ruthenium complexes or ruthenium compounds described in Patent Documents 1-3 to manufacture thin films via the ALD method, there is a problem that it is difficult to obtain high-quality ruthenium-containing thin films with less residual carbon. Furthermore, the ruthenium complexes described in Non-Patent Document 1 have an ALD window, but the use of such ruthenium complexes in the ALD method is not specifically described in Non-Patent Document 1.
[0011] Therefore, the object of the present invention is to provide a raw material for forming a high-quality ruthenium-containing thin film with less residual carbon by atomic layer deposition (ALD) and a method for manufacturing the thin film using the same. [Means for solving the problem]
[0012] As a result of repeated and active review, the inventors discovered that the above-mentioned problems could be solved by using a raw material for thin film formation in atomic layer deposition containing a ruthenium compound with a specific structure, and thus the present invention was completed.
[0013] That is, the present invention is a raw material for thin film formation by atomic layer deposition containing a ruthenium compound represented by the following general formula (1).
[0014]
[0015] (In the formula, R1 represents a hydrogen atom or a methyl group, and R2 and R3 each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms).
[0016] The present invention relates to a thin film formed using the above-described atomic layer deposition method with raw materials for thin film formation.
[0017] The present invention comprises a method for manufacturing a thin film containing ruthenium atoms by using the above-mentioned raw materials for thin film formation in atomic layer deposition to form a thin film containing ruthenium atoms on the surface of a substrate.
[0018] The present invention refers to a ruthenium compound represented by the following general formula (2).
[0019]
[0020] (In the formula, R4 represents an alkyl group having 1 to 5 hydrogen atoms).
[0021] The present invention relates to a raw material for thin film formation containing a ruthenium compound represented by the above general formula (2).
[0022] The present invention relates to a film formed using the above-mentioned raw materials for film formation.
[0023] This invention relates to a thin film manufacturing method that uses the aforementioned thin film forming raw materials to form a thin film containing ruthenium atoms on the surface of a substrate. [Effects of the Invention]
[0024] According to the present invention, a raw material for forming a high-quality ruthenium-containing thin film by atomic layer deposition method that can form a thin film with less residual carbon and a method for manufacturing a thin film using the same are provided.
Implementation Method
[0026] [Raw materials for thin film formation in atomic layer deposition method]
[0027] The raw material for thin film formation in the atomic layer deposition method of the present invention is characterized by containing a ruthenium compound represented by the above general formula (1).
[0028] In the above general formula (1), R1 represents a hydrogen atom or a methyl group, and R2 and R3 each independently represent a hydrogen atom or an alkyl group with 1 to 5 carbon atoms.
[0029] As alkyl groups having 1 to 5 carbon atoms represented by R2 and R3, examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, isopentyl, neopentyl, etc.
[0030] Based on the viewpoint that ruthenium-containing films are easy to manufacture with good productivity and low residual carbon content, R1 is preferably methyl. Based on the viewpoint that ruthenium compounds have high vapor pressure and are easy to manufacture with good productivity and low residual carbon content, R2 is preferably hydrogen or an alkyl group having 1 to 3 carbon atoms, more preferably hydrogen or methyl, and even more preferably hydrogen. Based on the viewpoint that ruthenium compounds have high vapor pressure and are easy to manufacture with good productivity and low residual carbon content, R3 is preferably hydrogen or an alkyl group having 1 to 3 carbon atoms, more preferably hydrogen or methyl, and even more preferably methyl.
[0031] As a preferred example of a ruthenium compound represented by general formula (1) used as a raw material for thin film formation in the atomic layer deposition method of the present invention, the compounds No.1 to No.12 below can be cited as examples, but the present invention is not limited to these ruthenium compounds. In addition, "Me" in the following compounds represents methyl and "Et" represents ethyl.
[0032]
[0033] The ruthenium compound represented by general formula (1) used in the atomic layer deposition method of the present invention for thin film formation is not particularly limited in its manufacturing method and can be manufactured by well-known synthesis methods. For example, it can be obtained by mixing RuCl2 (benzene) or RuCl2 (toluene) with sodium carbonate and any alcohol in the presence or absence of a solvent, stirring, and then mixing any diene compound and stirring and reacting after the reaction.
[0034] The raw materials for thin film formation in the atomic layer deposition method of the present invention only need to contain a ruthenium compound represented by the above general formula (1) as a precursor for the thin film, and its composition varies depending on the type of thin film intended. For example, in the case of manufacturing a thin film containing only ruthenium atoms as a metal, the raw materials for thin film formation in the atomic layer deposition method do not contain metal compounds or half-metal compounds other than ruthenium. On the other hand, in the case of manufacturing a thin film containing ruthenium atoms and metals and / or half-metals other than ruthenium atoms, the raw materials for thin film formation in the atomic layer deposition method may contain compounds containing the desired metal and / or compounds containing half-metals (hereinafter also referred to as "other precursors") in addition to the ruthenium compound represented by the above general formula (1).
[0035] In the case of a multi-component ALD process using multiple precursors, other precursors that can be used simultaneously with the ruthenium compound represented by the above general formula (1) are not particularly restricted and can be any well-known general precursors used for the raw materials for thin film formation in the ALD process.
[0036] Other precursors may include, for example, compounds consisting of one or more compounds selected from the group of compounds that use alcohols, diols, β-diketones, cyclopentadienes, and organic amines as organic ligands, and silicon or metals. Furthermore, examples of metals 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, yttrium, lanthanum, cerium, tungsten, neodymium, beryllium, samarium, europium, thorium, tungsten, dysprosium, holmium, erbium, thorium, ytterbium, or ferruginum.
[0037] Examples of alcohol compounds used as organic ligands in other precursors include alkane 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 Ether alcohols such as 1-dimethylethanol, 2-(2-methoxyethoxy)-1,1-dimethylethanol, 2-propoxy-1,1-diethylethanol, 2-tert-butoxy-1,1-diethylethanol, and 3-methoxy-1,1-dimethylpropanol; and 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.
[0038] Examples of diol compounds used as organic ligands for other precursors 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.
[0039] Examples of β-diketone compounds used as organic ligands for other precursors include acetoacetone, hexane-2,4-dione, 5-methylhexane-2,4-dione, heptane-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-ethyldecane-3,5-dione and 2,2-dimethyl-6-methyldecane-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-diperfluorohexylpropane-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.
[0040] Examples of cyclopentadiene compounds used as organic ligands for other precursors include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, isopropylcyclopentadiene, butylcyclopentadiene, dibutylcyclopentadiene, isobutylcyclopentadiene, terbutylcyclopentadiene, dimethylcyclopentadiene, tetramethylcyclopentadiene, pentamethylcyclopentadiene, etc.
[0041] Examples of organic amine compounds used as organic ligands of other precursors include methylamine, ethylamine, propylamine, isopropylamine, butylamine, dibutylamine, tert-butylamine, isobutylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, ethylmethylamine, propylmethylamine, isopropylmethylamine, etc.
[0042] Other precursors are well known in the art, and their manufacturing methods are also well known. For example, in the case of using an alcohol compound as an organic ligand, the precursor can be produced by reacting an inorganic salt of the previously described metal or its hydrate with an alkali metal alkoxide of the alcohol compound. Examples of inorganic salts of metals or their hydrates include metal halides and nitrates. Examples of alkali metal alkoxides include sodium alkoxides, lithium alkoxides, and potassium alkoxides.
[0043] In the multi-component ALD method described above, there are the following methods: a method in which raw materials for thin film formation by atomic layer deposition are vaporized and supplied independently by each component (hereinafter also referred to as "single-source method"), and a method in which a mixed raw material formed by mixing multi-component raw materials with a predetermined desired composition is vaporized and supplied (hereinafter also referred to as "cocktail source method"). In the case of single-source method, other precursors are preferably compounds whose thermal and / or oxidative decomposition behavior is similar to that of ruthenium compounds represented by the above general formula (1). In the case of cocktail source method, other precursors are preferably compounds that, except that their thermal and / or oxidative decomposition behavior is similar to that of ruthenium compounds represented by the above general formula (1), do not deteriorate due to chemical reaction during mixing.
[0044] In the case of the mixed source method of the multi-component ALD method, a mixture of ruthenium compound represented by the above general formula (1) and other precursors or a mixed solution of the mixture dissolved in an organic solvent can be used as a raw material for thin film formation in the atomic layer deposition method.
[0045] As an organic solvent, well-known general organic solvents may be used without particular restriction. Examples of such organic solvents include acetates such as ethyl acetate, butyl acetate, and methoxyethyl acetate; ethers such as tetrahydrofuran, tetrahydropiperan, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, dibutyl ether, and dioxane; 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... Hydrocarbons such as alkanes, 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, and the relationship between boiling point and flash point.
[0046] In the case where the raw material for thin film formation in the atomic layer deposition method of the present invention is a mixed solution containing an organic solvent, the total amount of the precursor in the raw material for thin film formation in the atomic layer deposition method can be adjusted to 0.01 mol / L to 2.0 mol / L, especially 0.05 mol / L to 1.0 mol / L. The reason for this is that it is easier to form high-quality ruthenium-containing thin films with less residual carbon.
[0047] Here, the total amount of precursors, in the case where the raw material for thin film formation in atomic layer deposition does not contain precursors other than the ruthenium compound represented by general formula (1), represents the amount of the ruthenium compound represented by the above general formula (1). In the case where the raw material for thin film formation in atomic layer deposition contains other precursors besides the ruthenium compound represented by the above general formula (1), it represents the total amount of the ruthenium compound represented by the above general formula (1) and other precursors.
[0048] The raw materials for thin film formation in the atomic layer deposition method of the present invention may contain nucleophilic reagents as needed, in order to improve the stability of ruthenium compounds and other precursors represented by the above general formula (1). Examples of such nucleophilic reagents include, for example, 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; tetraethylenetetramine; pentaethylenehexamine; 1,1,4,7,7-pentamethyldiethylenetriamine; and 1,1,4,7,10,10-hexamethyltriethylenetetramine. Polyamines such as amines and triethoxytriethylamine; cyclic polyamines such as tetraazacyclotetradecane and tetraazacyclododecane; heterocyclic compounds such as pyridine, pyrrolidine, piperidine, morpholine, N-methylpyrrolidine, N-methylpiperidine, N-methylmorpholine, tetrahydrofuran, tetrahydropiperan, 1,4-dioxane, oxazole, thiazole, and oxothiocyclopentane; β-keto esters such as methyl acetate, ethyl acetate, and 2-methoxyethyl acetate; or β-diketones such as acetoacetone, 2,4-hexanedione, 2,4-heptanedione, 3,5-heptanedione, and di-pentacyclomethane. The amount of these nucleophilic reagents used, based on the viewpoint that stability can be easily adjusted, is preferably in the range of 0.1 mol to 10 mol relative to the total amount of the precursor, and more preferably in the range of 1 mol to 4 mol.
[0049] The raw materials for thin film formation in the atomic layer deposition method of the present invention are preferably free of impurity metal elements, impurity halogens such as impurity chlorine, and impurity organic matter other than the components constituting them. The impurity metal element content is preferably 100 ppb or less per element, more preferably 10 ppb or less, and the total content is preferably 1 ppm or less, more preferably 100 ppb or less. In particular, when used as a gate insulating film, gate film, barrier layer, or wiring layer for LSI, the content of alkali metal elements and alkaline earth metal elements that affect the electrical properties of the obtained thin film must be reduced. The impurity halogen content 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 matter 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 raw materials used for thin film formation in atomic layer deposition (ALD) or during 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 moisture content of each of the precursors, organic solvents, and nucleophilic reagents is preferably 10 ppm or less, more preferably 1 ppm or less. The reason for setting the impurity metal element content, impurity halogen content, impurity organic content, and moisture content in the raw materials used for thin film formation in the ALD of this invention to be below the above values is that it facilitates the formation of high-quality ruthenium-containing thin films with less residual carbon.
[0050] Furthermore, the raw materials for thin film formation in the atomic layer deposition method of the present invention are preferably as free of particles as possible in order to reduce or prevent particulate contamination of the formed ruthenium-containing thin film. Specifically, in particle measurement using a liquid-phase light scattering particle detector, the number of particles larger than 0.3 μm in 1 ml of the raw materials for thin film formation in the atomic layer deposition method is preferably 100 or less, and the number of particles larger than 0.2 μm in 1 ml of the raw materials for thin film formation in the atomic layer deposition method is preferably 100 or less. This is because it is easy to obtain a uniform ruthenium-containing thin film.
[0051] [Method for manufacturing a thin film using a raw material for forming a thin film by atomic layer deposition containing a ruthenium compound represented by general formula (1)] Next, a method for manufacturing a thin film according to the present invention, which includes forming a ruthenium-containing thin film on the surface of a substrate using the above-mentioned raw material for forming a thin film by atomic layer deposition, will be described. The method for manufacturing the thin film of the present invention is not particularly limited if it includes forming a ruthenium-containing thin film using a raw material for thin film formation by atomic layer deposition, but it is preferred to include, for example, the following steps: a raw material introduction step, incorporating a raw material gas obtained by vaporizing the raw material for thin film formation by atomic layer deposition into a film-forming chamber in which a substrate is provided; and a thin film formation step, incorporating a ruthenium compound contained in the raw material gas, represented by general formula (1), through decomposition and / or chemical reaction to form a ruthenium-containing thin film on the surface of the aforementioned substrate. Between the raw material introduction step and the thin film formation step, a precursor film formation step is further included, in which a precursor film is formed on the surface of the substrate using a raw material for thin film formation by atomic layer deposition. The thin film formation step is more preferably a step in which the precursor film reacts with a reactive gas to form a ruthenium-containing thin film on the surface of the substrate. The reason for this is that it is easier to obtain a high-quality ruthenium-containing thin film with less residual carbon.
[0052] The method of conveying and supplying raw materials, the deposition method, the manufacturing conditions, the manufacturing equipment, etc. are not particularly restricted, and well-known general conditions and methods can be used.
[0053] The apparatus for manufacturing thin films using the atomic layer deposition method of the present invention with raw materials for thin film formation can use known ALD apparatuses. Examples of specific apparatuses include apparatuses that supply precursors with bubbles, as shown in Figures 1 and 3, or apparatuses with a vaporization chamber, as shown in Figures 2 and 4. Also, examples include apparatuses that can perform plasma treatment on reactive gases, as shown in Figures 3 and 4. Furthermore, it is not limited to single-piece apparatuses with a film-forming chamber (having a "deposition reaction section") as shown in Figures 1-4; apparatuses that can process multiple films simultaneously using a batch furnace can also be used. Moreover, these can also be used as CVD apparatuses.
[0054] Hereinafter, each step in the method for manufacturing such thin films will be explained.
[0055] The raw material introduction step of the present invention is a step of introducing a raw material gas obtained by vaporizing a raw material for thin film formation by atomic layer deposition into a film-forming cavity in which a substrate is disposed. Examples of methods for introducing a raw material gas obtained by vaporizing a raw material for thin film formation by atomic layer deposition into a film-forming cavity in which a substrate is disposed include gas delivery method, liquid delivery method, single source method, and mixed source method.
[0056] As a gas delivery method, for example as shown in Figures 1 and 3, the raw material for thin film formation using the atomic layer deposition method of the present invention is heated and / or vaporized to become a raw material gas in a raw material container storing the raw material for thin film formation using the atomic layer deposition method of the present invention, and the raw material gas is introduced into a film-forming cavity containing a substrate as needed, together with a carrier gas such as argon, nitrogen, or helium. As a liquid delivery method, for example as shown in Figures 2 and 4, the raw material for thin film formation using the atomic layer deposition method is delivered to a vaporization chamber in a liquid or solution state, vaporized to become a raw material gas by heating and / or vaporizing in the vaporization chamber, and the raw material gas is introduced into a film-forming cavity.
[0057] The single-source method is a method for supplying raw materials for thin film formation in atomic layer deposition (ALD) that includes multiple precursors. Examples include methods where each precursor is independently vaporized and supplied. The mixed-source method includes, for example, methods where a mixture of multiple precursors with a predetermined desired composition is vaporized and supplied. Raw materials for thin film formation in ALD that include such multiple precursors may also include nucleophilic reagents, etc.
[0058] The step of vaporizing the raw material for thin film formation using the atomic layer deposition method of the present invention into a raw material gas can be performed in the raw material container as described above, or in a vaporization chamber. In either case, it is preferable to vaporize the raw material for thin film formation using the atomic layer deposition method of the present invention at 0°C to 200°C. This is because it facilitates the formation of high-quality ruthenium-containing thin films. Furthermore, when the raw material for thin film formation using the atomic layer deposition method is vaporized into a raw material gas in the raw material container or in the vaporization chamber, the pressure in the raw material container and the pressure in the vaporization chamber are preferably in the range of 1 Pa to 10,000 Pa. This is because the vaporization of the raw material for thin film formation using the atomic layer deposition method becomes better.
[0059] Examples of substrate materials disposed within the film-forming cavity include silicon; ceramics such as silicon nitride, titanium nitride, tantalum nitride, titanium oxide, ruthenium oxide, zirconium oxide, hafnium oxide, and lanthanum oxide; glass; and metals such as cobalt and ruthenium. Examples of substrate shapes include plate-like, spherical, fibrous, and scaly. The surface of the substrate can be planar or form a three-dimensional structure such as a groove structure.
[0060] The thin film forming step of the present invention is a thin film forming step in which a ruthenium-containing thin film is formed on the surface of a substrate by decomposing and / or chemically reacting a ruthenium compound represented by general formula (1) contained in a raw material gas. The thin film forming step, as shown in Figures 1 to 4, is a step performed in a film-forming chamber in which a substrate is provided. The raw material gas and a reactive gas are introduced into the film-forming chamber, and a ruthenium-containing thin film is formed on the substrate within the film-forming chamber by the action of the reactive gas or by the action of the reactive gas combined with heat. In the case where the raw material introduction step and the thin film forming step include the precursor thin film forming step described later, the thin film forming step is preferably a step in which the precursor thin film reacts with the reactive gas to form a ruthenium-containing thin film on the surface of the aforementioned substrate. This is because it is easier to obtain a high-quality ruthenium-containing thin film with less residual carbon.
[0061] In the thin film formation step, when using heat to react the ruthenium compound represented by general formula (1) with the reactive gas, it is sufficient to heat the substrate and / or the film formation chamber. The heating temperature only needs to be in the range of room temperature to 500°C, but from the viewpoint of easily forming high-quality ruthenium-containing thin films, the range of 100°C to 450°C is preferred.
[0062] Examples of reactive gases include oxygen, ozone, nitrogen dioxide, nitric oxide, water vapor, hydrogen peroxide, formic acid, acetic acid, acetic anhydride, hydrogen, organic amine compounds such as monoalkylamines, dialkylamines, trialkylamines, and alkyldiamines, hydrazine, and ammonia. These reactive gases can be used alone or in mixtures of two or more. In the thin film formation step, the reactive gas is preferably a gas containing at least one gas selected from the group consisting of hydrogen, ammonia, oxygen, and ozone. This is because it facilitates the formation of high-quality ruthenium-containing thin films with less residual carbon.
[0063] The method for manufacturing a thin film according to the present invention preferably includes a precursor film formation step between the raw material introduction step and the thin film formation step, wherein a precursor film is formed on the surface of a substrate using a raw material for thin film formation by atomic layer deposition. The precursor film only needs to be able to form a ruthenium-containing film in the thin film formation step. As a method for forming such precursor films, a ruthenium compound represented by the above formula (1) in a raw material gas introduced into a film-forming chamber in which a substrate is provided is deposited (adsorbed) onto the surface of the substrate, thereby forming a precursor film on the surface of the substrate. At this time, heat can be applied by heating the substrate or heating the film-forming chamber. The conditions for forming the precursor film are not particularly limited, for example, the reaction temperature (substrate temperature), reaction pressure, deposition rate, etc. can be appropriately determined according to the type of raw material for thin film formation by atomic layer deposition. The reaction temperature is preferably in the range of 0°C to 500°C, and more preferably in the range of 100°C to 450°C. The reason for this is that it is easy to uniformly form a precursor film.
[0064] The deposition rate of the ruthenium compound represented by general formula (1) in the raw material gas can be controlled by the supply conditions (vaporization temperature, vaporization pressure), reaction temperature, and reaction pressure of the raw material for thin film formation in atomic layer deposition. If the deposition rate is too high, the properties of the resulting precursor film will deteriorate; if it is too low, production problems will occur. Therefore, the deposition rate in the precursor formation step is preferably in the range of 0.005 nm / min to 100 nm / min, and more preferably in the range of 0.01 nm / min to 50 nm / min.
[0065] The thin film manufacturing method of the present invention preferably includes a step of venting unreacted reactive gases, raw material gases, and byproduct gases from the film-forming cavity after the formation of the precursor thin film in the precursor thin film formation step or after the formation of the ruthenium-containing thin film in the thin film formation step. This is because it is easier to obtain high-quality ruthenium-containing thin films with less residual carbon. Ideally, the unreacted reactive gases, raw material gases, and byproduct gases should be completely vented from the film-forming cavity, but complete venting is not necessary. Examples of venting methods include, for instance, blowing inert gases such as helium, nitrogen, or argon into the film-forming cavity, venting by depressurizing the system, and a combination of these methods. The depressurization rate is preferably in the range of 0.01 Pa to 300 Pa, and more preferably in the range of 0.01 Pa to 100 Pa, based on the viewpoint of promoting the venting of unreacted reactive gases, raw material gases, and byproduct gases.
[0066] The method for manufacturing the thin film of the present invention may further include an application step of applying energy such as plasma, light, or voltage, or a step of using a catalyst. The timing of applying the energy and the timing of using the catalyst are not particularly limited. For example, it may be during the introduction of the raw material gas in the raw material gas introduction step, during heating in the precursor thin film formation step or the thin film formation step, during system venting in the venting step, during the introduction of the reactive gas in the thin film formation step, or between the above steps.
[0067] In the method for manufacturing the thin film of the present invention, when plasma treatment is performed, if the output is too large, it will cause greater damage to the substrate. Therefore, it is preferred to be 10W to 1,500W, and more preferably 50W to 600W.
[0068] In order to improve the electrical properties of the ruthenium-containing thin film, the method for manufacturing the thin film of the present invention may include an annealing step after the thin film is formed. The annealing step may be performed in an inert environment, an oxidizing environment, or a reducing environment. In cases where it is necessary to embed a step difference, a reflow step may be provided. Based on the viewpoint of easily manufacturing high-quality ruthenium-containing thin films with less residual carbon, the annealing temperature is preferably in the range of 200°C to 1,000°C, and more preferably in the range of 250°C to 500°C.
[0069] The method for manufacturing the thin film of the present invention can be a method that performs only one thin film formation step, or a method that performs two or more thin film formation steps, but is preferably a method that performs two or more thin film formation steps. The present invention sequentially performs a raw material gas introduction step, a precursor thin film formation step, an exhaust step, a thin film formation step, and an exhaust step, forming a ruthenium-containing thin film in one cycle. This cycle can be repeated several times until a ruthenium-containing thin film of the desired thickness is obtained, thus forming a ruthenium-containing thin film with the desired thickness. The thickness of the formed ruthenium-containing thin film can be controlled by the number of cycles. The deposition rate of the ruthenium-containing thin film obtained in each cycle is preferably in the range of 0.001 nm / min to 100 nm / min, more preferably in the range of 0.005 nm / min to 50 nm / min. The reason for this is that by setting the deposition rate within the above range, a uniform ruthenium-containing thin film is easily obtained.
[0070] [Thin Films Formed Using Raw Materials for Thin Film Forming via Atomic Layer Deposition] Thin films formed using the raw materials for thin film formation via atomic layer deposition of the present invention can be exemplified by thin films of ruthenium metal, ruthenium oxide, or ruthenium nitride. The aforementioned thin film manufacturing method can more effectively form ruthenium metal thin films. In the aforementioned thin film manufacturing method, the thin films of the present invention can be made into desired types of thin films by appropriately selecting other precursors, reactive gases, and manufacturing conditions. Due to their excellent electrical and optical properties, the thin films of the present invention can be widely used in the manufacture of, for example, electrode materials for memory devices such as DRAM devices, wiring materials for semiconductor devices, antimagnetic films for recording layers of hard disks, and catalyst materials for solid polymer fuel cells.
[0071] [Ruthenium compound] The ruthenium compound of the present invention is a ruthenium compound represented by the above general formula (2). The ruthenium compound of the present invention can be preferably used as a raw material for forming thin films for chemical vapor deposition, and is even more preferably used as a raw material for forming thin films for atomic layer deposition due to having an ALD window.
[0072] In the above general formula (2), the alkyl group with 1 to 5 carbon atoms represented by R 4 can be exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, terbutyl, n-pentyl, isopentyl, neopentyl, etc.
[0073] In the above general formula (2), R4 can be appropriately selected according to the manufacturing method of the applicable thin film. In the case of a manufacturing method of a thin film having a step of vaporizing ruthenium compound, R4 is selected in a way that increases the vapor pressure and decreases the melting point, so that high-quality ruthenium-containing thin films can be easily manufactured with good productivity.
[0074] Based on the view that ruthenium compounds have high vapor pressure and can be easily manufactured into smooth, high-quality ruthenium-containing films with less residual carbon, R4 is preferably a hydrogen atom or an alkyl group with 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a methyl group.
[0075] Furthermore, in the case of using a method for manufacturing thin films that utilizes the MOD method without a vaporization step, R4 can be arbitrarily selected based on the solubility of the solvent used, the thin film formation reaction, etc.
[0076] As a preferred example of a ruthenium compound represented by the above general formula (2), examples such as the ruthenium compounds No.7 to No.9 mentioned above can be cited, but the present invention is not limited to such ruthenium compounds.
[0077] The method of manufacturing the ruthenium compound represented by the above general formula (2) is not particularly limited, and it can be manufactured by well-known synthetic methods. Specifically, it can be manufactured by the same method as the ruthenium compound represented by the above general formula (1).
[0078] [Film Forming Raw Material] The film forming raw material of the present invention is characterized by containing a ruthenium compound represented by the above general formula (2). The composition of the film forming raw material of the present invention varies depending on the type of film intended. For example, in the case of manufacturing a film containing only ruthenium atoms as a metal, the film forming raw material does not contain metal compounds or half-metal compounds other than ruthenium. On the other hand, in the case of manufacturing a film containing ruthenium atoms and metals and / or half-metals other than ruthenium atoms, the film forming raw material may contain, in addition to the ruthenium compound represented by the above general formula (2), desired metal compounds and / or half-metal compounds (hereinafter also referred to as "other precursors"). The precursor, namely the ruthenium compound represented by the above general formula (2), has properties suitable for the CVD method, therefore the film forming raw material of the present invention is useful as a film forming raw material for the CVD method. Among them, the ruthenium compound represented by the above general formula (2) has an ALD window, so the thin film forming raw material of the present invention is particularly useful as a thin film forming raw material for atomic layer deposition.
[0079] In the case of a multi-component CVD method using multiple precursors, there are no particular restrictions on other precursors that can be used simultaneously with the ruthenium compound represented by the above general formula (2), but well-known general precursors used in the raw materials for thin film formation in the CVD method can be used.
[0080] As other precursors, the same precursors as those exemplified in the above-mentioned [raw materials for thin film formation by atomic layer deposition] section can be used.
[0081] The multi-component CVD method described above includes the following methods: a method in which the raw materials for thin film formation are vaporized and supplied independently by each component (hereinafter also referred to as the "single-source method"), and a method in which the multi-component raw materials are pre-mixed with a desired composition and then vaporized and supplied (hereinafter also referred to as the "mixed-source method"). In the case of the single-source method, other precursors are preferably compounds whose thermal and / or oxidative decomposition behavior is similar to that of the ruthenium compound represented by the above general formula (2). In the case of the mixed-source method, other precursors are preferably compounds that, in addition to having thermal and / or oxidative decomposition behavior similar to that of the ruthenium compound represented by the above general formula (2), do not deteriorate due to chemical reactions during mixing.
[0082] In the case of the mixed source method in the multi-component CVD method, a mixture of ruthenium compound represented by the above general formula (2) and other precursors or a mixed solution of the mixture dissolved in an organic solvent can be used as raw material for thin film formation.
[0083] As the organic solvent, the same organic solvent as that exemplified in the above-mentioned [raw materials for thin film formation in atomic layer deposition method] section can be used.
[0084] When the raw material for thin film formation of the present invention is a mixed solution containing an organic solvent, the total amount of the precursor in the raw material for thin film formation only needs to be adjusted to 0.01 mol / L to 2.0 mol / L, particularly 0.05 mol / L to 1.0 mol / L. The reason for this is that it is easy to form a high-quality ruthenium-containing thin film with less residual carbon.
[0085] Here, the total amount of precursors refers to the amount of ruthenium-containing compounds as expressed in general formula (2) when the raw materials for thin film formation do not contain precursors other than the ruthenium compound expressed in general formula (2). When the raw materials for thin film formation contain other precursors besides the ruthenium compound expressed in general formula (2), it refers to the total amount of the ruthenium compound expressed in general formula (2) and other precursors.
[0086] The raw materials for thin film formation of the present invention may contain a nucleophilic reagent as needed, in order to improve the stability of the ruthenium compound and other precursors represented by the above general formula (2). As such nucleophilic reagent, the same nucleophilic reagent as exemplified in the above [raw materials for thin film formation by atomic layer deposition] section can be used.
[0087] The raw materials for thin film formation of the present invention are preferably free from impurity metallic elements, impurity halogens such as impurity chlorine, and impurity organic matter other than the components constituting them. The impurity metallic element content is preferably 100 ppb or less per element, more preferably 10 ppb or less, and the total content is preferably 1 ppm or less, more preferably 100 ppb or less. Especially when used as gate insulating films, gate films, barrier films, or wiring layers for LSIs, it is necessary to reduce the content of alkali metal elements and alkaline earth metal elements that affect the electrical properties of the resulting ruthenium-containing thin film. The impurity halogen content 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 matter 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 formation in both the raw materials used for film formation and during film formation, it is advisable to remove moisture from the precursors, organic solvents, and nucleophilic reagents as much as possible before use to reduce their respective moisture content. The moisture content of each of the precursors, organic solvents, and nucleophilic reagents is preferably 10 ppm or less, and more preferably 1 ppm or less. The reason for setting the impurity metal element content, impurity halogen content, impurity organic content, and moisture in the raw materials used for film formation of the present invention to be below the above values is that it facilitates the formation of high-quality ruthenium-containing films with less residual carbon.
[0088] Furthermore, the raw material for thin film formation of the present invention preferably contains as few particles as possible in order to reduce or prevent particulate contamination of the formed ruthenium-containing thin film. Specifically, in particle measurement using a liquid-phase light scattering particle detector, the number of particles larger than 0.3 μm is preferably 100 or less per 1 ml of the raw material for thin film formation, and the number of particles larger than 0.2 μm is also preferably 100 or less per 1 ml of the raw material for thin film formation. The reason for this is that it is easier to obtain a uniform ruthenium-containing thin film.
[0089] [Method for manufacturing a thin film using a raw material for thin film formation containing a ruthenium compound represented by general formula (2)] Next, a method for manufacturing a thin film according to the present invention, which includes forming a ruthenium-containing thin film on the surface of a substrate using the aforementioned raw material for thin film formation, will be described. The method for manufacturing a thin film according to the present invention is not particularly limited if it includes forming a ruthenium-containing thin film using a raw material for thin film formation. It is preferred to include, for example, the following steps: a raw material introduction step, incorporating a raw material gas obtained by vaporizing the raw material for thin film formation into a film-forming cavity in which a substrate is provided; and a thin film formation step, incorporating the ruthenium compound represented by general formula (2) contained in the raw material gas through decomposition and / or chemical reaction to form a ruthenium-containing thin film on the surface of the aforementioned substrate. Between the raw material introduction step and the thin film formation step, a precursor film formation step is further included, in which a precursor film is formed on the surface of a substrate using a raw material for thin film formation. The thin film formation step is more preferably a step in which the precursor film is reacted with a reactive gas to form a ruthenium-containing thin film on the surface of the substrate. The reason is that it is easy to obtain high-quality ruthenium-containing films with less residual carbon.
[0090] The method of conveying and supplying raw materials, the deposition method, the manufacturing conditions, the manufacturing equipment, etc. are not particularly restricted, and well-known general conditions and methods can be used.
[0091] The apparatus for manufacturing a thin film using the raw material for thin film formation of the present invention can be a known ALD apparatus. As a specific example of the apparatus, the same ALD apparatus as exemplified in the section "[Method for manufacturing a thin film using a raw material for thin film formation of atomic layer deposition containing a ruthenium compound represented by general formula (1)]" can be used. Furthermore, these can also be used as CVD apparatuses.
[0092] Hereinafter, each step in the method for forming such thin films will be described.
[0093] The raw material introduction step of the present invention is a raw material introduction step in which the raw material gas obtained by vaporizing the raw material for thin film formation is introduced into a film-forming cavity in which a substrate is provided. As for the method of introducing raw material for thin film formation, the method exemplified in the above-mentioned [method of manufacturing a thin film using a raw material for thin film formation in atomic layer deposition method containing a ruthenium compound represented by general formula (1)] can be used, so the description here is omitted.
[0094] The thin film forming step of the present invention is a step of forming a ruthenium-containing thin film on the surface of a substrate by decomposing and / or chemically reacting the ruthenium compound contained in the raw material gas represented by general formula (2). Regarding the method of forming the thin film, since the method exemplified in the above-mentioned [method of manufacturing a thin film using a raw material for thin film forming by atomic layer deposition containing a ruthenium compound represented by general formula (1)] can be used, the description here is omitted.
[0095] The method for manufacturing the thin film of the present invention is preferably located between the raw material introduction step and the thin film formation step, and further includes a precursor film formation step for forming a precursor film on the surface of a substrate using a raw material for thin film formation. The precursor film is only required to form a ruthenium-containing thin film in the thin film formation step. Since the method for forming such precursor films can be exemplified in the above-described method of manufacturing a thin film using a raw material for thin film formation in atomic layer deposition of a ruthenium compound represented by general formula (1), the description here is omitted.
[0096] The preferred method for manufacturing the thin film of the present invention is to perform a venting step after the formation of the precursor thin film in the precursor thin film formation step or after the formation of the ruthenium-containing thin film in the thin film formation step, thereby venting the unreacted reactive gas, raw material gas, and byproduct gas from the film-forming cavity. This makes it easier to obtain a high-quality ruthenium-containing thin film with less residual carbon. Ideally, the unreacted reactive gas, raw material gas, and byproduct gas should be completely vented from the film-forming cavity, but complete venting is not necessary. Since this venting step is the same as the venting step described in the above section [Method for manufacturing a thin film using a raw material for thin film formation by atomic layer deposition of a ruthenium compound represented by general formula (1)], its description here is omitted.
[0097] The method for manufacturing the thin film of the present invention may further include an energy application step such as applying plasma, light, or voltage, or a step of using a catalyst. The energy application step or the step of using a catalyst described here is the same as the energy application step or the step of using a catalyst described in the above-described [method for manufacturing a thin film using a raw material for forming a thin film by atomic layer deposition of a ruthenium compound represented by general formula (1)], so the description here is omitted.
[0098] In order to improve the electrical properties of the ruthenium-containing thin film, the method for manufacturing the thin film of the present invention may further include an annealing step after the thin film is formed. The annealing step here is the same as the annealing step described in the above-mentioned [method for manufacturing a thin film using a raw material for forming a thin film by atomic layer deposition method containing a ruthenium compound represented by general formula (1)], so the description here is omitted.
[0099] The thin film manufacturing method of the present invention can be a method that performs only one thin film formation step, or a method that performs two or more thin film formation steps, but is preferably a method that performs two or more thin film formation steps. The present invention simply performs the raw material gas introduction step, the precursor thin film formation step, the venting step, the thin film formation step, and the venting step in sequence, forming a thin film through a series of operations as one cycle. This cycle is repeated several times until a ruthenium-containing thin film of the required thickness is obtained, thus forming a ruthenium-containing thin film with the desired thickness. The thickness of the formed ruthenium-containing thin film can be controlled by the number of cycles. The deposition rate of the ruthenium-containing thin film obtained in each cycle is preferably in the range of 0.001 nm / min to 100 nm / min, more preferably in the range of 0.005 nm / min to 50 nm / min. The reason for this is that by setting the deposition rate within the above range, it is easy to obtain a uniform ruthenium-containing thin film.
[0100] [Thin Films Formed Using Raw Materials for Thin Film Formation] Thin films formed using the raw materials for thin film formation of the present invention can be exemplified by thin films of ruthenium metal, ruthenium oxide, and ruthenium nitride. The aforementioned thin film manufacturing method can more effectively form ruthenium metal thin films. In the aforementioned thin film manufacturing method, the thin films of the present invention, by appropriately selecting other precursors, reactive gases, and manufacturing conditions, can form thin films of desired types. Due to their excellent electrical and optical properties, the thin films of the present invention can be widely used in the manufacture of, for example, electrode materials for memory devices such as DRAM devices, wiring materials for semiconductor devices, antimagnetic films for recording layers of hard disks, and catalyst materials for solid polymer fuel cells.
[0101] <Other> Examples of the following can be cited in this disclosure. [1] A raw material for thin film formation in atomic layer deposition, which contains a ruthenium compound represented by the following general formula (1),
[0102]
[0103] (In the formula, R1 represents a hydrogen atom or a methyl group, and R2 and R3 each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms).
[0104] [2] The raw material for thin film formation in atomic layer deposition as in [1], wherein R2 in the aforementioned general formula (1) is a hydrogen atom.
[0105] [3] Raw materials for thin film formation in atomic layer deposition method such as [1] or [2], wherein R 3 in the aforementioned general formula (1) is an alkyl group having 1 to 5 carbon atoms.
[0106] [4] A raw material for thin film formation in any of the atomic layer deposition methods of [1] to [3], wherein R3 in the aforementioned general formula (1) is methyl.
[0107] [5] A thin film formed using a thin film forming raw material by an atomic layer deposition method as described in any one of [1] to [4].
[0108] [6] A method for manufacturing a thin film, comprising forming a thin film containing ruthenium atoms on the surface of a substrate using a thin film forming material of atomic layer deposition method as described in any one of [1] to [4].
[0109] [7] The method for manufacturing a thin film as described in [6] includes: a raw material introduction step of introducing a raw material gas obtained by vaporizing the raw material for thin film formation in the aforementioned atomic layer deposition method into a film forming cavity in which a substrate is provided, and a thin film forming step of decomposing and / or chemically reacting the ruthenium compound represented by general formula (1) contained in the aforementioned raw material gas to form a thin film containing ruthenium atoms on the surface of the aforementioned substrate.
[0110] [8] The method for manufacturing a thin film as described in [7] further includes, between the aforementioned raw material introduction step and the aforementioned thin film formation step, a precursor film formation step for forming a precursor film on the surface of the aforementioned substrate using the aforementioned atomic layer deposition method for forming a thin film, wherein the aforementioned thin film formation step is a step of forming a thin film containing ruthenium atoms on the surface of the aforementioned substrate by reacting the aforementioned precursor film with a reactive gas.
[0111] [9] A ruthenium compound, which is represented by the following general formula (2),
[0112]
[0113] (In the formula, R4 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms).
[0114]
[10] A raw material for thin film formation, which contains a ruthenium compound as in [9].
[0115]
[11] A thin film, which is made using a thin film forming material as described in
[10] .
[0116]
[12] A method for manufacturing a thin film, comprising forming a thin film containing ruthenium atoms on the surface of a substrate using a thin film forming material as described in
[10] .
[0117]
[13] The method for manufacturing a thin film as described in
[12] includes a raw material introduction step of introducing a raw material gas obtained by vaporizing the raw material for forming the aforementioned thin film into a film forming cavity in which a substrate is provided, and a thin film forming step of decomposing and / or chemically reacting the ruthenium compound contained in the aforementioned raw material gas, represented by general formula (2), to form a thin film containing ruthenium atoms on the surface of the aforementioned substrate.
[0118]
[14] The method for manufacturing a thin film as described in
[13] further includes, between the aforementioned raw material introduction step and the aforementioned thin film formation step, a precursor film formation step for forming a precursor film on the surface of the aforementioned substrate using the aforementioned thin film formation raw material, wherein the aforementioned thin film formation step is a step of reacting the aforementioned precursor film with a reactive gas to form a thin film containing ruthenium atoms on the surface of the aforementioned substrate. [Example]
[0119] Hereinafter, the present invention will be described in detail based on embodiments. However, the present invention is not limited to the following embodiments, etc.
[0120] [Example 1] Preparation of ruthenium compound No. 7: 22.14 g of [RuCl2 (toluene)], 2.57 g of sodium carbonate, and 18.0 ml of 2-propanol were added to a reaction flask and dissolved. The mixture was stirred at room temperature for 2 hours. 21.4 ml of butadiene / 15% hexane solution was added to the solution and stirred under reflux for 6 hours. The reaction solution was desolventized in an oil bath at 90°C under reduced pressure. 50.0 ml of hexane was added to the residue and the mixture was filtered. The filtrate was desolventized in an oil bath at 65°C under reduced pressure. The resulting ruthenium complex was distilled in an oil bath at 110°C and 90 Pa to obtain a yellow liquid compound No. 7 (yield 0.80 g, 40%).
[0121] (Analytical Values) (1) Atmospheric pressure TG-DTA mass reduction temperature of 50%: 200℃ (760 Torr, Ar flow rate: 100 ml / min, temperature rise 10℃ / min) (2) Reduced pressure TG-DTA mass reduction temperature of 50%: 111℃ (10 Torr, Ar flow rate: 50 ml / min, temperature rise 10℃ / min) (3) 1H-NMR (deuterated benzene) 0.275-0.310ppm (2H, double peak after double peak), 1.782ppm (3H, single peak), 1.850-1.898ppm (2H, double peak after double peak), 4.716-4.760ppm (3H, multi-peak), 4.914-4.928ppm (2H, multi-peak), 4.997-5.024ppm (2H, multi-peak) (4) Elemental analysis results by ICP-AES: Ru: 40.87 mass% (theoretical value 40.89 mass%), C: 53.42 mass% (theoretical value 53.41 mass%), H: 5.71 mass% (theoretical value 5.70 mass%)
[0122] [Example 2] Preparation of ruthenium compound No. 8: 25.00 g of [RuCl2 (toluene)], 6.01 g of sodium carbonate, and 24.0 ml of 2-propanol were added to a reaction flask and dissolved. The mixture was stirred at room temperature for 2 hours. 4.73 ml of isoprene solution was added to the solution and stirred under reflux for 6 hours. The reaction solution was desolventized in an oil bath at 90°C under reduced pressure. 50.0 ml of hexane was added to the residue and the mixture was filtered. The filtrate was desolventized in an oil bath at 65°C under reduced pressure. The resulting ruthenium complex was distilled in an oil bath at 110°C and 90 Pa to obtain a yellow liquid compound No. 8 (yield 1.96 g, 40%).
[0123] (Analytical Values) (1) Atmospheric pressure TG-DTA 50% mass reduction temperature: 200℃ (760 Torr, Ar flow rate: 100 ml / min, temperature rise 10℃ / min) (2) Vacuum pressure TG-DTA 50% mass reduction temperature: 111℃ (10 Torr, Ar flow rate: 50 ml / min, temperature rise 10℃ / min) (3) 1H-NMR (deuterated benzene) 0.145-0.168ppm (1H, double peak after double peak), 0.341ppm (1H, single peak), 1.744 ppm (3H, singlet), 1.823-1.842ppm (1H, doublet and doublet), 1.943ppm (4H, singlet), 4.693-4.754ppm (2H, multi-peak), 4.798-4.826ppm (2H, multi-peak), 4.887-4.915ppm (1H, multi-peak), 5.067-5.094ppm (1H, triplet) (4) Elemental analysis results by ICP-AES: Ru: 38.70 mass% (theoretical value 38.68 mass%), C: 55.14 mass% (theoretical value 55.15 mass%), H: 6.16 mass% (theoretical value 6.17 mass%)
[0124] [Evaluation Example] The physical properties of the compounds were evaluated for No.1, No.2, No.4, No.7, No.8 and No.10 ruthenium compounds and Comparative Compound 1 and Comparative Compound 2. In the following chemical formulas, "Me" represents methyl, "Et" represents ethyl and "iPr" represents isopropyl. (1) Melting point evaluation The state of the compound at 25°C under normal pressure was observed by visual observation. The melting point of the solid was measured at 25°C using a micro melting point measuring device. The results are shown in Table 1. (2) Temperature (°C) when TG-DTA decreases by 50% by mass under normal pressure Using TG-DTA at 10 Torr, Ar flow rate: 50 mL / min, heating rate: 10°C / min, and scanning temperature range of 30°C to 600°C, the temperature (°C) when the weight of the test compound decreases by 50% by mass was used as the "temperature (°C) when TG-DTA decreases by 50% by mass under normal pressure" for evaluation. The lower the temperature (°C) at which the mass percentage of atmospheric pressure TG-DTA50 decreases, the more readily vapor can be obtained at low temperatures. The results are shown in Table 1.
[0125]
[0126]
[0127] As shown in Table 1, the temperature at which the mass percentage of TG-DTA50 decreases at atmospheric pressure for Comparative Compound 1 and Comparative Compound 2 is above 208°C. In contrast, the ruthenium compounds No. 1, No. 2, No. 4, No. 7, No. 8, and No. 10 all have a temperature below 203°C at atmospheric pressure when the mass percentage of TG-DTA50 decreases, indicating they are compounds with higher vapor pressures. Furthermore, the ruthenium compounds No. 7, No. 8, and No. 10 have melting points below 50°C, indicating they are compounds with lower melting points. Among them, the ruthenium compounds No. 7 and No. 8 are liquid at 25°C, indicating they are compounds with particularly low melting points.
[0128] [Fabrication of thin films by ALD method] Next, thin films are manufactured using the compounds evaluated above as raw materials for thin film formation by atomic layer deposition.
[0129] [Example 3] Using ruthenium compound No. 8 as the raw material for thin film formation in atomic layer deposition (ALD), a thin film was formed on the surface of a silicon wafer as a substrate using the ALD apparatus shown in Figure 1 under the following conditions. After analyzing the composition of the thin film using X-ray photoelectron spectroscopy, it was confirmed that the thin film was a ruthenium metal film with a residual carbon content of less than 0.1 atom%. Furthermore, after measuring the film thickness using scanning electron microscopy, the thin film formed on the surface of the silicon wafer was a smooth film with a thickness of 11 nm, and the film thickness obtained per cycle was approximately 0.11 nm.
[0130] (Conditions) Manufacturing method: ALD process; Reaction temperature (matrix temperature): 230℃; Reaction gas: Oxygen
[0131] (Steps) One series of steps (1) to (4) below is taken as 1 cycle, and the cycle is repeated 100 times. (1) The vapor of the raw material for film formation (raw material gas) vaporized under the conditions of raw material container temperature: 100°C and raw material container pressure: 100Pa is introduced into the film forming chamber (raw material introduction step), and the raw material gas is deposited on the substrate surface to form a precursor film at a pressure of 100Pa for 20 seconds (precursor film formation step). (2) The undeposited raw material gas is vented from the system by blowing argon gas for 15 seconds (venting step). (3) The reactive gas is introduced into the film forming chamber at a pressure of 100Pa for 20 seconds to make the precursor film react with the reactive gas (film formation step). (4) The unreacted reactive gas and byproduct gas are vented from the system by blowing argon gas for 15 seconds (venting step).
[0132] [Example 4] Except that the ruthenium compound No. 7 was used instead of the ruthenium compound No. 8 as the raw material for thin film formation in atomic layer deposition, a thin film was fabricated on the surface of a silicon wafer using the same method as in Example 3. After analyzing the composition of the thin film using X-ray photoelectron spectroscopy, it was confirmed that the thin film was a ruthenium metal thin film, and the residual carbon content was less than 0.1 atom%. Furthermore, after measuring the film thickness using scanning electron microscopy, the thin film formed on the surface of the silicon wafer was a smooth film with a thickness of 10 nm, and the film thickness obtained in each cycle was approximately 0.10 nm.
[0133] [Example 5] Except that the ruthenium compound No. 10 was used instead of the ruthenium compound No. 8 as the raw material for thin film formation in atomic layer deposition, the reactive gas was changed to hydrogen plasma (plasma output: 100W), and the ALD device was changed to the ALD device shown in Figure 3, a thin film was fabricated on the surface of a silicon wafer using the same method as in Example 3. After analyzing the composition of the thin film using X-ray photoelectron spectrometry, it was confirmed that the thin film was a ruthenium metal thin film, and the residual carbon content was less than 0.1 atom%. Furthermore, after measuring the film thickness using scanning electron microscopy, the thin film formed on the surface of the silicon wafer was a smooth film with a thickness of 9 nm, and the film thickness obtained per cycle was approximately 0.09 nm.
[0134] [Comparative Example 1] Except that Comparative Compound 1 was used instead of the ruthenium compound in No. 8 as the raw material for thin film formation in atomic layer deposition, and the raw material container temperature was changed to 110°C, a thin film was formed on the surface of a silicon wafer using the same method as in Example 3. After analyzing the composition of the thin film using X-ray photoelectron spectrometry, the thin film was found to be a ruthenium-containing film with a residual carbon content of 2.7 atom%. Furthermore, after measuring the film thickness using scanning electron microscopy, the thin film formed on the surface of the silicon wafer was found to be an uneven film with a thickness of 6-7 nm.
[0135] [Comparative Example 2] Except that comparative compound 2 was used instead of ruthenium compound No. 8 as the raw material for thin film formation in atomic layer deposition, and the raw material container temperature was changed to 125°C, a thin film was formed on the surface of a silicon wafer using the same method as in Example 3. After analyzing the composition of the thin film using X-ray photoelectron spectrometry, the thin film was found to contain ruthenium, with a residual carbon content of 3.2 atom%. Furthermore, after measuring the film thickness using scanning electron microscopy, the thin film formed on the surface of the silicon wafer was found to be an uneven film with a thickness of 5-6 nm.
[0136] Since the vapor pressures of Comparative Compound 1 and Comparative Compound 2 are relatively low, the temperature of the raw material container in Comparative Examples 1 and 2 must be increased compared to Examples 3-5. As a result, it is believed that Comparative Compound 1 and Comparative Compound 2 undergo thermal decomposition, forming an uneven ruthenium-containing film with a high residual carbon content.
[0137] As shown above, when using the atomic layer deposition method of the present invention to manufacture ruthenium-containing thin films, high-quality ruthenium-containing thin films with smoothness and low residual carbon can be obtained with good productivity. In particular, when using ruthenium compounds No. 7 and No. 8 as raw materials for atomic layer deposition, high-quality ruthenium-containing thin films with smoothness and significantly low residual carbon can be obtained with good productivity. [Simplified Explanation of the Diagram]
[0025] [Figure 1] is a schematic diagram showing one example of an ALD apparatus used in the method for manufacturing a thin film according to the present invention. [Figure 2] is a schematic diagram showing another example of an ALD apparatus used in the method for manufacturing a thin film according to the present invention. [Figure 3] is a schematic diagram showing another example of an ALD apparatus used in the method for manufacturing a thin film according to the present invention. [Figure 4] is a schematic diagram showing another example of an ALD apparatus used in the method for manufacturing a thin film according to the present invention.
Claims
1. A raw material for thin film formation in atomic layer deposition, comprising a ruthenium compound represented by the following general formula (1), (where R1 represents a hydrogen atom or a methyl group, and R2 and R3 each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms).
2. The raw material for thin film formation in the atomic layer deposition method of claim 1, wherein R2 in the aforementioned general formula (1) is a hydrogen atom.
3. Raw materials for thin film formation in atomic layer deposition as claimed in claim 1, wherein R3 in the aforementioned general formula (1) is an alkyl group having 1 to 5 carbon atoms.
4. Raw materials for thin film formation in atomic layer deposition as claimed in claim 1, wherein R3 in the aforementioned general formula (1) is methyl.
5. A thin film formed using a thin film forming raw material obtained by atomic layer deposition as described in any one of claims 1 to 4.
6. A method for manufacturing a thin film, comprising forming a thin film containing ruthenium atoms on the surface of a substrate using a thin film forming material of atomic layer deposition as described in any one of claims 1 to 4.
7. The method for manufacturing a thin film as claimed in claim 6, comprising: a raw material introduction step of introducing a raw material gas obtained by vaporizing the raw material for thin film formation in the aforementioned atomic layer deposition method into a film forming cavity in which a substrate is disposed, and a thin film forming step of decomposing and / or chemically reacting the ruthenium compound contained in the aforementioned raw material gas, represented by general formula (1), to form a thin film containing ruthenium atoms on the surface of the aforementioned substrate.
8. The method for manufacturing a thin film as claimed in claim 7, wherein between the aforementioned raw material introduction step and the aforementioned thin film formation step, a precursor thin film formation step is further included, which uses the aforementioned atomic layer deposition method for thin film formation raw materials to form a precursor thin film on the surface of the aforementioned substrate, wherein the aforementioned thin film formation step is a step of reacting the aforementioned precursor thin film with a reactive gas to form a thin film containing ruthenium atoms on the surface of the aforementioned substrate.
9. A ruthenium compound represented by the following general formula (2), (where R4 represents an alkyl group having 1 to 5 carbon atoms).
10. A raw material for thin film formation, comprising a ruthenium compound as claimed in claim 9.
11. A thin film formed using the thin film forming raw material as claimed in claim 10.
12. A method for manufacturing a thin film, comprising forming a thin film containing ruthenium atoms on the surface of a substrate using a thin film forming material as claimed in claim 10.
13. The method for manufacturing a thin film as claimed in claim 12, comprising a raw material introduction step of introducing a raw material gas obtained by vaporizing the raw material for forming the aforementioned thin film into a film forming cavity in which a substrate is disposed, and a thin film forming step of decomposing and / or chemically reacting a ruthenium compound contained in the aforementioned raw material gas, represented by general formula (2), onto the surface of the aforementioned substrate to form a thin film containing ruthenium atoms.
14. The method for manufacturing a thin film as claimed in claim 13, wherein between the aforementioned raw material introduction step and the aforementioned thin film formation step, a precursor film formation step is further included, which uses the aforementioned raw material for thin film formation to form a precursor film on the surface of the aforementioned substrate, wherein the aforementioned thin film formation step is a step of reacting the aforementioned precursor film with a reactive gas to form a thin film containing ruthenium atoms on the surface of the aforementioned substrate.