TW202124396A - Thin-film-forming raw material for atomic-layer deposition method, and method for producing zinc-containing thin film using the same - Google Patents

Abstract

Provided is a novel prophylactic agent or therapeutic agent for functional gastrointestinal disorders or xerostomia. The present invention is a therapeutic agent or prophylactic agent that is for functional gastrointestinal disorders and that contains, as an active ingredient, an azabenzoimidazole compound represented by formula [1] (in the formula, the symbols are as defined in the description) or a pharmaceutically acceptable salt thereof, or a solvate thereof.

Description

Thin film forming raw material for atomic layer deposition method and manufacturing method of zinc-containing thin film using the same

The present invention relates to a thin film forming material used in an atomic layer deposition method containing a zinc compound having a specific structure and a method for manufacturing a zinc-containing thin film using the same.

Zinc is used as a component for forming compound semiconductors, and as a raw material for forming a thin film containing zinc, and various compounds have been reported.

As the method of manufacturing the thin film, for example, a sputtering method, an ion plating method, a MOD method such as a coating thermal decomposition method or a sol gel method, a CVD method, etc. are mentioned. Among them, the atomic layer deposition method (hereinafter sometimes referred to as ALD method), one of the CVD methods, is the best because of its excellent composition control and step coverage, suitable for mass production, and mixing and integration. Suitable manufacturing process.

Although there have been various reports about the raw materials that can be used in the vapor phase thin film formation methods such as CVD and ALD methods, the raw materials that can be applied to the thin film formation of the ALD method must have a sufficient width in the temperature range called the ALD window. . Even the thin film forming materials that can be used in the CVD method are not applicable to the ALD method in most cases.

In the production method of the metal-containing thin film, for example, Patent Document 1 proposes many metal compounds such as bis(di-tertiary butylamino) zinc as a raw material for forming a metal oxide thin film of a substrate. Patent Document 2 discloses the use of a raw material for MOCVD that contains a zinc raw material produced by reacting dimethyl zinc, diethyl zinc, triethylamine adduct of dimethyl zinc, etc., with ammonia, primary or secondary amines. A ZnSe film is formed. In Non-Patent Document 1, it is disclosed that an alkyl (dialkyl amide) zinc compound is used as a zinc precursor, and a thin film is produced by the MOCVD method. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5290488 [Patent Document 2] Japanese Patent Application Laid-Open No. 10-51031 [Non-Patent Literature]

[Non-Patent Document 1] Polyhedron, Vol. 16, No. 20, pp3593-3599, (1997); "The Properties of some volatile alkyl(di-alkylamido) zinc(II) and bis (di-alkylamido) zinc compounds: potential zinc precursors in MOCVD"

[The problem to be solved by the invention]

The thin film forming materials used in the ALD method are not only required to have a wide ALD window, but also low melting point, high volatility, reaction with reactive gas at low temperature, and good productivity to produce thin films. However, although Patent Document 1 has a description about the ALD method, there is no specific description about the applicability of the zinc compound to the ALD method. In Patent Document 2 and Non-Patent Document 1, various zinc amide compounds are described as zinc raw materials for ZnSe thin films. However, although these documents disclose methods for producing zinc-containing thin films using a zinc amide compound as a raw material for MOCVD, they do not disclose the use of ALD to produce zinc-containing thin films.

Therefore, the object of the present invention is to provide a thin film forming raw material of a zinc-containing compound suitable as a raw material for the ALD method, which has a low melting point, high volatility, and can react with a reactive gas at a low temperature, and has good productivity by using it. A method of manufacturing zinc-containing film to produce a smooth film with good quality. [Means to solve the problem]

As a result of repeated active reviews, the inventors found that a thin film forming raw material for the ALD method containing a zinc compound with a specific structure can solve the above-mentioned problems, thus completing the present invention. That is, the present invention provides a thin film forming raw material for ALD method, which contains a zinc compound represented by the following general formula (1),

In the formula, R ¹ and R ² each independently represent an alkyl group having 1 to 5 carbon atoms, a trimethylsilyl group, or a trifluoromethyl group, but R ¹ and R ² represent different groups.

In addition, in the film forming raw material of the present invention, it is preferable that in the general formula (1), R ¹ is a tertiary alkyl group and R ² is a secondary alkyl group.

Furthermore, in the film forming raw material of the present invention, it is more preferable that in the general formula (1), R ¹ is a tertiary butyl group and R ² is an isopropyl group.

The present invention provides a method for manufacturing a zinc-containing thin film using the ALD method, which includes introducing a raw material gas for gasifying a thin film forming raw material for the ALD method of the present invention into a processing environment, and depositing zinc compounds in the raw gas The first step of forming a precursor layer on the surface of the substrate, and the second step of introducing a reactive gas into the processing environment to cause the precursor layer to react with the reactive gas.

Furthermore, in the manufacturing method of the present invention, the reactive gas is preferably an oxidizing gas, and the zinc-containing film is a zinc oxide film.

Furthermore, in the manufacturing method of the present invention, the reactive gas is preferably a gas containing ozone or water vapor.

In addition, in the manufacturing method of the present invention, the temperature at which the precursor layer and the reactive gas are reacted is preferably in the range of 50°C to 200°C.

Furthermore, it is preferable that at least one of between the first step and the second step and after the second step has a step of exhausting the gas of the processing environment. [Effects of the invention]

According to the present invention, by containing a specific zinc compound, it is possible to provide a thin film forming raw material for ALD that has a low melting point, high volatility, and can react with a reactive gas at a low temperature. It is also possible to provide a method for producing a zinc-containing thin film with good quality and smoothness by ALD method using the thin film forming raw material of the present invention.

＜Film forming materials＞

First, the thin film forming raw material used in the ALD method of the present invention will be described. The thin film forming raw material of the present invention is characterized by containing a zinc compound represented by the above general formula (1), and the zinc compound is used as a precursor when the thin film is formed by the ALD method.

In the above general formula (1), R ¹ and R ² each independently represent an alkyl group having 1 to 5 carbon atoms, a trimethylsilyl group, or a trifluoromethyl group, but R ¹ and R ² are different groups.

Since the above-mentioned zinc compound is used as a precursor when forming a thin film by the ALD method, it is preferably a liquid at a normal pressure of 25°C, and the temperature when 50% by mass of the reduced pressure thermogravimetric thermal analysis device (TG-DTA) is reduced Below 100°C.

Here, in the above general formula (1), ^{examples of the alkyl group having 1 to 5 carbon atoms represented by R 1} and R ^{2 are,} for example, methyl, ethyl, propyl, isopropyl, n-butyl, isopropyl Butyl, second butyl, tertiary butyl, n-pentyl, isopentyl, second pentyl, tertiary pentyl, etc.

In the present invention, ^{the zinc compound with R 1} being a tertiary alkyl group and R ² being a secondary alkyl group has a low melting point, high volatility, can react with reactive gas at low temperature, and can form a zinc-containing film with good productivity. Preferably, a ^{zinc compound in which R 1} is a tertiary butyl group and R ² is an isopropyl group is better because of its more significant effect.

As specific examples of the zinc compound represented by the above general formula (1), the following No. 1 to No. 20 are exemplified, but the present invention is not limited to these compounds. In addition, in the following No.1~No.20 compounds, "Me" means "methyl", "Et" means "ethyl", "iPr" means "isopropyl", and "tBu" means "third butyl""Base","sBu" means "second butyl", "iBu" means "isobutyl", "tAm" means "third amyl", "SiMe ₃ " means "trimethylsilyl", "CF ₃ " means "trifluoromethyl".

The method for producing the compound represented by the above general formula (1) is not particularly limited, and the compound can be produced by applying a well-known reaction. As a manufacturing method, for example, when R ¹ is a tertiary alkyl group and R ² is a secondary alkyl group, the dialkylamine having these alkyl groups is dissolved in tetrahydrofuran (THF) and reacted with n-butyl lithium (nBuLi) After preparing the THF solution of the lithium dialkylamide compound, the solution was added dropwise to the ether solution of zinc chloride to react the lithium dialkylamide compound with zinc chloride, and the solvent was removed. The resulting residue It was obtained by adding hexane to the filtrate and filtering, and after distilling off the solvent from the filtrate, it was purified by distillation.

The thin film forming raw material used in the ALD method of the present invention only needs to contain the zinc compound represented by the above general formula (1) as the precursor of the thin film, and its composition varies depending on the type of thin film to be used. For example, when a thin film containing only zinc as a metal is produced, the raw material for forming the thin film of the present invention does not contain metal compounds or semimetal compounds other than zinc. On the other hand, when manufacturing a thin film containing zinc metal and a metal and/or semimetal other than zinc, the film forming raw material of the present invention may contain a compound containing a desired metal and/or a compound containing the desired metal in addition to the zinc compound represented by the general formula (1) Or semi-metal compounds (hereinafter also referred to as "other precursors").

In addition, in the ALD method of a multi-component system using plural precursors, other precursors that can be used with the zinc compound represented by the above general formula (1) are not particularly limited, and the thin film forming materials used in the ALD method can be used The well-known general precursors.

As the above-mentioned other precursors, for example, one of the group of compounds used as organic ligands selected from alcohol compounds, diol compounds, β-diketone compounds, cyclopentadiene compounds, organic amine compounds, etc. Or two or more compounds with silicon or metal. In addition, as the metal species of the precursor, examples are 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, samarium, neodymium , 鉕, samarium, europium, 釓, 鋱, dysprosium, 鈥, erbium, 銩, ytterbium or 镏.

Examples of alcohol compounds used as organic ligands for other precursors are, for example, methanol, ethanol, propanol, isopropanol, butanol, sec-butanol, isobutanol, tert-butanol, pentanol, and isoamyl alcohol. Alkanols such as alcohol and tertiary amyl alcohol; 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-methyl Oxy-1-methylethanol, 2-methoxy-1,1-dimethylethanol, 2-ethoxy-1,1-dimethylethanol, 2-isopropoxy-1,1- Dimethylethanol, 2-butoxy-1,1-dimethylethanol, 2-(2-methoxyethoxy)-1,1-dimethylethanol, 2-propoxy-1, Ether alcohols such as 1-diethylethanol, 2-second butoxy-1,1-diethylethanol, 3-methoxy-1,1-dimethylpropanol, etc.; dimethylaminoethanol , Ethylmethylaminoethanol, diethylaminoethanol, dimethylamino-2-pentanol, ethylmethylamino-2-pentanol, dimethylamino-2-methyl-2-pentanol Dialkylamino alcohols such as alcohol, ethylmethylamino-2-methyl-2-pentanol, diethylamino-2-methyl-2-pentanol, etc.

Examples of diol compounds used as organic ligands of the other precursors are, for example, 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- Pentylene glycol, 2,4-hexanediol, 2,4-dimethyl-2,4-pentanediol, etc.

Examples of β-diketone compounds used as organic ligands of the other precursors are, for example, acetone, 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, 2,9-dimethylnonane-4,6-dione, 2-methyl-6-ethyldecane-3 ,5-Dione, 2,2-dimethyl-6-ethyldecane-3,5-dione and other alkyl substituted β-diketones; 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-Diketone, 1,3-diperfluorohexylpropane-1,3-dione and other fluorine-substituted β-diketones; 1,1,5,5-tetramethyl-1-methoxy Hexane-2,4-dione, 2,2,6,6-tetramethyl-1-methoxyheptane-3,5-dione, 2,2,6,6-tetramethyl-1 -(2-Methoxyethoxy)heptane-3,5-dione and other ether substituted β-diketones, etc.

Examples of cyclopentadiene compounds used as organic ligands of other precursors are, for example, cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, isopropyl ring Pentadiene, butylcyclopentadiene, second butylcyclopentadiene, isobutylcyclopentadiene, tertiary butylcyclopentadiene, dimethylcyclopentadiene, tetramethylcyclopentadiene Diene, pentamethylcyclopentadiene, etc., the organic amine compound used as the above-mentioned organic ligand is exemplified by methylamine, ethylamine, propylamine, isopropylamine, butylamine, second butylamine, tertiary butylamine, iso Butylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, ethylmethylamine, propylmethylamine, isopropylmethylamine, etc.

The above-mentioned other precursors are known in the technical field, and their manufacturing methods are also known. To cite an example of the production method, for example, when an alcohol compound is used as a ligand, a precursor can be produced by reacting the aforementioned inorganic salt of the metal or its hydrate with the alkali metal alkoxide of the alcohol compound. Here, examples of metal inorganic salts or hydrates thereof include metal halides and nitrates, and examples of alkali metal alkoxides include sodium alkoxide, lithium alkoxide, potassium alkoxide, and the like.

In the above-mentioned multi-component system ALD method, there are a method of separately vaporizing and supplying the thin film forming raw materials with each component (hereinafter referred to as the "single source method") and a mixed raw material in which the multi-component raw materials are mixed in a desired composition in advance. The method of gasification and supply (hereinafter referred to as "mixed source method"). In the case of the single source method, as the aforementioned other precursor, a compound whose thermal and/or oxidative decomposition behavior is similar to that of the zinc compound represented by the aforementioned general formula (1) is preferable. In the mixed source method, as the above-mentioned other precursors, except that the thermal and/or oxidative decomposition behavior is similar to the zinc compound represented by the above-mentioned general formula (1), it is preferably one that does not cause deterioration due to chemical reaction or the like during mixing.

In the mixed source method of the multi-component ALD method, a mixture of the zinc compound represented by the general formula (1) and other precursors or a mixed solution in which the mixture is dissolved in an organic solvent can be used as a raw material for film formation.

The organic solvent is not particularly limited, and well-known general organic solvents can be used. Examples of the organic solvent include acetates such as ethyl acetate, butyl acetate, methoxyethyl acetate, etc.; tetrahydrofuran, tetrahydropyran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, three Ethylene glycol dimethyl ether, dibutyl ether, dioxane and other ethers; methyl butyl ketone, methyl isobutyl ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone, methyl Ketones such as amyl ketone, cyclohexanone, methyl cyclohexanone, etc.; hexane, cyclohexane, methyl cyclohexane, dimethyl cyclohexane, ethyl cyclohexane, heptane, octane, Hydrocarbons such as toluene and xylene; 1-cyanopropane, 1-cyanobutane, 1-cyanohexane, cyanocyclohexane, cyanobenzene, 1,3-dicyanopropane, 1, Hydrocarbons with cyano groups such as 4-dicyanobutane, 1,6-dicyanohexane, 1,4-dicyanocyclohexane, and 1,4-dicyanobenzene; pyridine, methyl Pyridine and so on. These organic solvents can be used alone or in combination of two or more according to the solubility of the solute, the relationship between the use temperature and the boiling point, and the ignition point.

When the thin film forming raw material used in the ALD method of the present invention is a mixed solution with the above-mentioned organic solvent, it is preferably prepared so that the total amount of the precursor in the thin film forming raw material is 0.01 mol/liter to 2.0 mol/liter, particularly preferably 0.05 mol/liter ~ 1.0 mol/liter.

In addition, the thin film forming raw material used in the ALD method of the present invention may contain a nucleophilic reagent as needed in order to improve the stability of the zinc compound represented by the general formula (1) and other precursors. Examples of the nucleophilic reagent include glycol ethers such as glyme, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether. Class, 18-crown-6, dicyclohexyl-18-crown-6, 24-crown-8, dicyclohexyl-24-crown-8, dibenzo-24-crown- Crown ethers of grade 8, ethylenediamine, N,N'-tetramethylethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine , 1,1,4,7,7-pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetramine, triethoxytriethylene Polyamines such as base amines, cyclic polyamines such as Cyclam and cyclen, pyridine, pyrrolidine, piperidine, morpholine, N- Heterocyclic compounds such as methylpyrrolidine, N-methylpiperidine, N-methylmorpholine, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, oxazole, thiazole, oxalane, etc. Classes, β-keto esters such as methyl acetylacetate, ethyl acetylacetate, 2-methoxyethyl acetate, etc. or acetylacetone, 2,4-hexanedione, 2,4 -Β-diketones such as heptanedione, 3,5-heptanedione, and dippentylmethane. The usage amount of these nucleophilic reagents is 1 mol relative to the total amount of the precursor, preferably in the range of 0.1 mol to 10 mol, and more preferably in the range of 1 mol to 4 mol.

The so-called total amount of precursor, when the thin film forming raw material used in the ALD method of the present invention does not contain metal compounds and semi-metal compounds other than zinc compounds, it means the zinc compound represented by the above general formula (1) and other precursors containing zinc The total amount of the substance is the total amount of the zinc compound represented by the above general formula (1) and the other precursor when the film forming raw material of the present invention contains other precursors.

The thin film forming raw material used in the ALD method of the present invention is desirably free of impurities such as impurity metal elements, impurity chlorine and other impurity halogens and impurity organic elements other than the constituent components. The impurity metal element content is preferably 100 ppb or less per element, more preferably 10 ppb or less, and the total amount is preferably 1 ppm or less, and more preferably 100 ppb or less. In particular, when using gate insulating films, gate films, and barrier films as 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 thin film. The impurity halogen content is preferably 100 ppm or less, more preferably 10 ppm or less, and still more preferably 1 ppm or less. The total organic content of impurities is preferably 500 ppm or less, more preferably 50 ppm or less, and still more preferably 10 ppm or less. In addition, since moisture is the cause of particle generation in the film forming raw material and particle generation in the film formation, in order to reduce the respective moisture in the precursors, organic solvents and nucleophilic reagents, it is better to remove as much as possible before use. Moisture. The moisture content of each of the precursor, organic solvent, and nucleophilic reagent is preferably 10 ppm or less, and more preferably 1 ppm or less.

In addition, in order to reduce or prevent particle contamination of the formed film, the film forming material used in the ALD method of the present invention preferably does not contain particles as much as possible. Specifically, in the particle measurement of the liquid phase by the light scattering type liquid particle detector, the number of particles larger than 0.3μm in 1ml of the liquid phase is preferably 100 or less, and more preferably the number of particles larger than 0.2μm is less than It is 100 or less in 1 ml of liquid phase.

＜Method of manufacturing zinc-containing film＞ Next, the method of manufacturing the zinc-containing thin film of the present invention using the above-mentioned thin film forming raw material for the ALD method will be described.

A well-known ALD device can be used for the device used for manufacturing the zinc-containing thin film by the ALD method of the present invention. Examples of specific devices include, for example, the device that can supply precursors by bubbling as shown in FIGS. 1 and 3, and the device with a gasification chamber as shown in FIGS. 2 and 4. Another example is a device that can perform plasma treatment on reactive gas as shown in FIG. 3 and FIG. 4. It is not limited to a single-chip device equipped with a film forming chamber (hereinafter referred to as a "deposition reaction section") as shown in Figs.

The method for producing a zinc-containing thin film by the ALD method of the present invention is characterized by the step of introducing the raw material gas for vaporizing the above-mentioned thin film forming raw material into the deposition reaction part (processing environment) to make the raw material gas The step of depositing a zinc compound on the surface of the substrate to form a precursor layer (the first step); and the step of introducing the reactive gas into the deposition reaction part (processing environment) to make the precursor layer react with the reactive gas (the second step). In addition, at least one of between the first step and the second step and after the second step has a step of exhausting the gas of the deposition reaction part (processing environment) (exhausting step).

As an embodiment of the method for manufacturing a zinc-containing thin film of the present invention, the first step, the exhaust step, the second step, and the exhaust step are performed in sequence as described above, and the series of operations of deposition are set as one cycle, and the plurality of operations are repeated In this cycle, the method of manufacturing a zinc-containing film will be described. The following is a detailed description of each step.

(Step 1) The first step includes the step of vaporizing the above-mentioned thin film forming raw material used in the ALD method into vapor (hereinafter referred to as "raw material gas"), introducing the raw material gas into the raw material gas introduction step of the film forming chamber provided with the substrate, and making the The zinc compound in the raw material gas is deposited on the surface of the substrate provided in the deposition reaction part to form a precursor layer. The precursor layer forming step is formed.

・Introduction procedure of raw material gas As a method of transporting and supplying the thin film forming raw material used in the ALD method in the step of introducing the raw material gas, there is shown in Figs. And/or depressurize and vaporize into vapor, and introduce the vapor to the deposition reaction part where the substrate is installed together with carrier gas such as argon, nitrogen, helium, etc., as required, as shown in Fig. 2 and Fig. 4, A liquid transport method in which the thin film forming raw material is transported to the vaporization chamber in a liquid or solution state, heated and/or decompressed in the vaporization chamber to vaporize into vapor, and the vapor is introduced as a raw material gas into the deposition reaction part. In the case of the gas delivery method, the zinc compound represented by the above general formula (1) itself can be used as a thin film forming raw material. In the case of the liquid delivery method, the zinc compound represented by the above general formula (1) or a solution in which the compound is dissolved in an organic solvent can be used as a thin film forming raw material. The mixture and mixed solution may further contain nucleophilic reagents and the like.

In addition to the above-mentioned gas delivery method and liquid delivery method, as the method used in the raw material gas introduction step, as the ALD method of a multi-component system containing a plurality of precursors, there are a single source method and a mixed method as described in the column of the thin film forming materials Source method, but when any introduction method is used, it is preferable to vaporize the thin film forming raw material used in the ALD method of the present invention at 0°C to 200°C. In addition, the pressure in the raw material container and the pressure in the gasification chamber when the film-forming raw material is gasified into steam in the raw material container or the gasification chamber is preferably in the range of 1 Pa to 10,000 Pa.

Here, as the material of the substrate provided in the deposition reaction part, for example, silicon; silicon nitride, titanium nitride, tantalum nitride, titanium oxide, titanium nitride, ruthenium oxide, zirconium oxide, hafnium oxide, lanthanum oxide, etc. The ceramics; glass; metal cobalt, metal ruthenium and other metals. Examples of the shape of the base material include a plate shape, a spherical shape, a fibrous shape, and a scaly shape. The surface of the substrate can be a flat surface or a three-dimensional structure such as a groove structure.

・Precursor layer formation steps The precursor layer forming step is to deposit the zinc compound represented by the above general formula (1) in the raw material gas introduced into the deposition reaction part provided with the substrate on the surface of the substrate to form a precursor layer on the surface of the substrate. At this time, the substrate may be heated, or the deposition reaction part may be heated to apply heat. The conditions for forming the precursor layer are not particularly limited. For example, the reaction temperature (substrate temperature), reaction pressure, deposition rate, etc. can be appropriately determined according to the thickness of the desired precursor layer and the types of film forming materials. The reaction temperature is preferably 100°C or more, which is the temperature at which the film forming raw material for the ALD method of the present invention fully reacts on the surface of the substrate, and more preferably 100°C to 200°C. The reaction pressure is preferably 1 Pa to 1,000 Pa, more preferably 10 Pa to 1,000 Pa.

In addition, the above-mentioned deposition rate can be controlled by the supply conditions (vaporization temperature, vaporization pressure), reaction temperature, and reaction pressure of the film forming raw materials. If the deposition rate is high, the characteristics of the obtained film may deteriorate, and if it is small, there may be problems with productivity. Therefore, it is preferably 0.01 nm/min to 100 nm/min, and more preferably 1 nm/min to 50 nm/min.

In addition, when the thin film forming raw material contains other precursors than the zinc compound represented by the general formula (1), the other precursors are deposited on the surface of the substrate together with the zinc compound.

(Exhaust step) After the above-mentioned first step, the raw material gas containing the zinc compound not deposited on the surface of the substrate is exhausted from the deposition reaction part. At this time, it is ideal to completely exhaust the raw material gas from the deposition reaction part, but it is not necessary to completely exhaust it. Examples of the exhaust method include a method in which an inert gas such as helium, nitrogen, and argon is used to purge the inside of the deposition reaction part, a method in which the inside of the system is decompressed and exhausted, and a method in which these are combined. The degree of decompression during decompression is preferably in the range of 0.01 Pa to 300 Pa, more preferably in the range of 0.01 Pa to 100 Pa.

(Step 2) In the second step, after the exhaust step, a reactive gas is introduced into the deposition reaction part, and the reactive gas and the precursor layer are deposited on the substrate by the action of the reactive gas or the action of the reactive gas and the action of heat. The zinc compound on the surface reacts. Examples of the above-mentioned reactive gas include, for example, oxygen, ozone, nitrogen dioxide, nitrogen monoxide, water vapor, hydrogen peroxide, oxidizing gases such as formic acid, acetic acid, acetic anhydride, reducing gases such as hydrogen, monoalkylamines, Organic amine compounds such as dialkylamine, trialkylamine, and alkylene diamine, nitriding gases such as hydrazine, ammonia, etc. These reactive gases may be used alone, or two or more of them may be mixed and used. Among them, the thin film forming raw material used in the ALD method of the present invention has the property of reacting with oxidizing gas at a particularly low temperature, especially reacting with ozone and water vapor at low temperature. From the viewpoint that the film thickness obtained per cycle is thick and the film can be produced with good productivity, it is preferable to use a gas containing ozone or water vapor as the reactive gas, and more preferably to use a gas containing water vapor. When the reactive gas is an oxidizing gas, a zinc oxide-containing film is formed. In addition, when the reactive gas is an oxidizing gas, as a precursor of the first step, a zinc oxide thin film is formed when only the zinc compound of the general formula (1) is used.

The temperature in the case of using heat to act is preferably 50°C to 200°C, more preferably 100°C to 200°C. Since the ALD window (ALD window) of the combination of the thin film forming raw material for the ALD method and the reactive gas of the present invention is about 100℃~150℃, it is more preferable to use the precursor in the range of 100℃~150℃ The material layer reacts with the reactive gas. In addition, the pressure of the deposition reaction part when performing this step is preferably 1 Pa to 10,000 Pa, more preferably 10 Pa to 1,000 Pa.

The thin film forming raw material used in the ALD method of the present invention has good reactivity with the above-mentioned reactive gas. By using the thin film forming raw material of the present invention, a high-quality zinc-containing thin film with low residual carbon content can be produced with good productivity.

(Exhaust step) After the second step, unreacted reactive gas and by-product gas are exhausted from the deposition reaction part. At this time, it is ideal to completely exhaust the reactive gas and the by-product gas from the deposition reaction part, but it is not necessary to completely exhaust it. The decompression degree as the exhaust method and the decompression is the same as the exhaust step performed between the first step and the second step described above.

As explained above, the first step, the exhaust step, the second step and the exhaust step are carried out in sequence, the deposition of the series of operations is set as a cycle, and the cycle is repeated several times until a film with the necessary film thickness is obtained, and a thin film with the necessary film thickness is obtained. Zinc-containing thin film of desired film thickness. According to the thin film manufacturing method using the ALD method, the thickness of the formed zinc-containing thin film can be controlled by the number of cycles described above.

In addition, in the method of manufacturing a zinc-containing thin film of the present invention, as shown in FIGS. 3 and 4, energy such as plasma, light, voltage, etc. may be applied to the deposition reaction part, and a catalyst may also be used. The period of applying the energy and the period of using the catalyst are not particularly limited. For example, during the introduction of the raw material gas used in the thin film formation of the ALD method in the first step, heating during the formation of the precursor layer, or the second step When the reactive gas is introduced, heating when the reactive gas is reacted with the precursor layer, and when the exhaust is exhausted in the system of the exhaust step, it may be between the above steps.

In addition, in the method of manufacturing the film of the present invention, after the zinc-containing film is formed, in order to obtain better electrical properties, annealing treatment can also be performed in an inert, oxidizing, or reducing environment. When embedding, a reflow step can also be set. The temperature in this case is 200°C to 1,000°C, preferably 250°C to 500°C.

The zinc-containing thin film produced using the thin film forming raw material for the ALD method of the present invention can be made into desired types of metals, oxide ceramics, nitride ceramics, glass, etc., by appropriately selecting other precursors, reactive gases, and production conditions的膜。 The film. The film is known to exhibit electrical properties, optical properties, etc., and is applied to various usage patterns. For example, these films can be widely used in the production of electrode materials for memory devices represented by DRAM devices, resistive films, diamagnetic films used in the recording layer of hard disks, and catalyst materials for solid polymer fuel cells, etc. . [Example]

Hereinafter, the present invention will be explained in more detail using manufacturing examples, examples, and the like. However, the present invention is not limited at all by the following examples and the like.

[Manufacturing Example 1] Synthesis of Compound No.6 In a 200mL 3-necked flask, 5g (43.43mmol) of N-isopropyl-2-methylpropane-2-amine and THF (150mL) were charged and cooled to -78 After °C, 27.7 mL (43.47 mmol) of nBuLi (1.57M hexane solution) was added dropwise over 30 minutes. After slowly raising the temperature to room temperature, it was stirred for 18 hours to prepare a THF solution of lithium tert-butyl(isopropyl)amide. Put 43.4 g (20.7 mmol) of zinc chloride (6.5% ether solution) and 30 mL of THF into a 500 mL 4-necked flask, and add the tertiary butyl (isopropyl THF solution of lithium amide). After heating to room temperature and stirring for 18 hours, the solvent was removed under reduced pressure at a bath temperature of 64°C. After adding 100 mL of hexane to the obtained residue and stirring, it was filtered. The solvent was removed under reduced pressure at a bath temperature of 64°C, and the resulting yellow liquid was distilled under the conditions of a bath temperature of 79°C and 51 Pa to obtain a colorless transparent liquid (yield: 3.8 g, yield: 63%). The obtained colorless and transparent liquid was confirmed to be compound No. 6 of the target compound by the analysis result of ^{1 H-NMR and the result of elemental analysis by ICP emission spectroscopy. The result of 1} H-NMR analysis of the obtained colorless transparent liquid is shown below.

(1) ¹ H-NMR (deuterated benzene) analysis results 1.15ppm (12H, doublet (doublet)), 1.18ppm (18H, singlet (singlet)), 3.09ppm (2H, septet)

(2) Elemental analysis (theoretical value) Zn: 22.3% (22.25%)

The following evaluations were performed using the compound No. 6 obtained in the above-mentioned Production Example 1 and the following comparative compounds No. 1 to No. 4. In addition, in the following comparative compounds No.1 to No.4, "iPr" means "isopropyl", "tBu" means "tertiary butyl", "sBu" means "second butyl", and "iBu" Means "isobutyl".

(1) Evaluation of state and melting point By visually observing the state of the compound under normal pressure at 25°C, the melting point of the solid compound was measured using a small melting point measuring device. These results are shown in Table 1, respectively.

(2) The temperature when 50% by mass of TG-DTA is reduced by decompression (℃) Use TG-DTA to measure with 10 Torr, argon flow rate: 50 mL/min, heating rate 10°C/min, and the scanning temperature range as 30°C~600°C. The temperature (°C) when the mass of the test compound is reduced by 50% by mass is used as "Decompression TG-DTA 50% reduction temperature (°C)" was evaluated. The lower the temperature (°C) when the reduced pressure TG-DTA 50% by mass decreases, the more vapor can be obtained at low temperatures. The results are shown in Table 1 respectively.

[Example 2] Manufacture of zinc-containing film Compound No. 6 was used as a thin film forming raw material, and the ALD device of FIG. 1 was used to produce a zinc-containing thin film on a silicon wafer under the following conditions. After confirming the composition of the obtained film by X-ray electron spectroscopy, the obtained film was a zinc oxide film, and no residual carbon was detected. In addition, the film thickness was measured with a scanning electron microscope, and it was a smooth film with a film thickness of approximately 6 nm, and the film thickness obtained per cycle was approximately 0.04 nm.

(ALD device conditions) Substrate: Silicon wafer Reaction temperature (substrate temperature): 100℃ Reactive gas: water vapor (step) Set a series of steps (1) to (4) below as one cycle, and repeat the cycle 150 times. (1) Introduce the film forming material vapor (raw material gas) vaporized under the conditions of the material container temperature: 50℃ and the pressure in the material container of 100 Pa into the deposition reaction section, and deposit zinc compound on the surface of the silicon wafer at a pressure of 100 Pa for 10 seconds , Form a precursor layer. (2) With 15 seconds of argon purge, the raw material gas containing the undeposited zinc compound is exhausted from the system. (3) The reactive gas is introduced into the deposition reaction section, and the precursor layer is reacted with the reactive gas at a system pressure of 100 Pa for 0.2 seconds. (4) With argon purging for 60 seconds, unreacted reactive gas and by-product gas are exhausted from the system.

[Comparative Example 5] Except that the compound No. 6 was changed to the comparative compound No. 1, the zinc-containing thin film was produced on the silicon wafer by the same method as in Example 2, but a smooth film could not be obtained. In addition, residual carbon was detected in the resulting film.

[Comparative Example 6] Except that the compound No. 6 was changed to the comparative compound No. 2, the zinc-containing thin film was produced on the silicon wafer by the same method as in Example 2, but a smooth film could not be obtained. In addition, residual carbon was detected in the resulting film.

[Comparative Example 7] Except that the compound No. 6 was changed to the comparative compound No. 3, a zinc-containing thin film was produced on a silicon wafer by the same method as in Example 2, but a smooth film could not be obtained. In addition, residual carbon was detected in the resulting film.

[Comparative Example 8] Except that the compound No. 6 was changed to the comparative compound No. 4, a zinc-containing thin film was produced on a silicon wafer by the same method as in Example 2, but a smooth film could not be obtained. In addition, residual carbon was detected in the resulting film.

From the above, it can be confirmed that the specific zinc compound used in the thin film forming raw material used in the ALD method has a low melting point, high volatility, and reacts with a reactive gas at a low temperature, thereby confirming that the zinc oxide thin film can be produced with good productivity. The zinc-containing film.

Fig. 1 is a schematic diagram showing an example of an ALD device used in the method of manufacturing a zinc-containing thin film of the present invention. [Fig. 2] A schematic diagram showing another example of the ALD device used in the method of manufacturing the zinc-containing thin film of the present invention. Fig. 3 is a schematic diagram showing yet another example of the ALD device used in the method of manufacturing the zinc-containing thin film of the present invention. Fig. 4 is a schematic diagram showing still another example of the ALD device used in the method of manufacturing the zinc-containing thin film of the present invention.

Claims (8)

A thin film forming raw material for atomic layer deposition, which contains a zinc compound represented by the following general formula (1),

(In the formula, R ¹ and R ² each independently represent an alkyl group having 1 to 5 carbon atoms, a trimethylsilyl group, or a trifluoromethyl group, but R ¹ and R ² are different groups). The film forming raw material of claim 1, wherein in the above general formula (1), R ¹ is a tertiary alkyl group, and R ² is a secondary alkyl group. The film forming raw material of claim 1 or 2, wherein in the above general formula (1), R ¹ is a tertiary butyl group and R ² is an isopropyl group. A method for manufacturing a zinc-containing thin film using an atomic deposition method, which includes introducing a raw material gas that vaporizes the thin film forming raw material according to any one of claims 1 to 3 into a processing environment, so that the zinc compound in the raw gas The first step of depositing on the surface of the substrate to form a precursor layer, and The second step of introducing the reactive gas into the processing environment to cause the precursor layer to react with the reactive gas. The method for manufacturing a zinc-containing thin film of claim 4, wherein the reactive gas is an oxidizing gas, and the zinc-containing thin film is a zinc oxide thin film. The method for manufacturing a zinc-containing thin film of claim 4 or 5, wherein the aforementioned reactive gas is a gas containing ozone or water vapor. The method for producing a zinc-containing thin film according to any one of claims 4 to 6, wherein the temperature at which the precursor layer and the reactive gas are reacted is in the range of 50°C to 200°C. The method for manufacturing a zinc-containing thin film according to any one of claims 4 to 7, wherein at least one of between the first step and the second step and after the second step has the gas of the processing environment Steps of exhaust.

Images