WO2017030150A1 - Method for producing aluminum oxide film, material for producing aluminum oxide film and aluminum compound - Google Patents

Method for producing aluminum oxide film, material for producing aluminum oxide film and aluminum compound Download PDF

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WO2017030150A1
WO2017030150A1 PCT/JP2016/074032 JP2016074032W WO2017030150A1 WO 2017030150 A1 WO2017030150 A1 WO 2017030150A1 JP 2016074032 W JP2016074032 W JP 2016074032W WO 2017030150 A1 WO2017030150 A1 WO 2017030150A1
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aluminum oxide
oxide film
aluminum
compound
amidinato
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PCT/JP2016/074032
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French (fr)
Japanese (ja)
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白井　昌志
央 二瓶
貴匡 宮崎
純一 向
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宇部興産株式会社
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F5/00—Compounds containing elements of Groups 3 or 13 of the Periodic System
    • C07F5/06—Aluminium compounds
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides

Definitions

  • the present disclosure relates to a method for manufacturing an aluminum oxide film, a raw material for manufacturing an aluminum oxide film, and an aluminum compound.
  • the aluminum oxide film is useful as a gate insulating film and has been widely applied in the semiconductor field. Therefore, an aluminum compound (a raw material for producing an aluminum oxide film) for producing an aluminum oxide film has been studied (see, for example, Patent Documents 1 to 4).
  • Non-Patent Document 1 discloses (ditertiary butyl (methyl) amidinato) dimethylaluminum as a polymerization catalyst. However, no physical property values and characteristics are described.
  • Non-Patent Document 2 discloses a synthesis example of (ditertiary butyl (ethyl) amidinato) diethylaluminum. However, no properties are described.
  • JP 2006-526705 A Japanese Patent No. 4716193 JP 2007-138296 A Korean Registered Patent No. 10-121861
  • a method for manufacturing an aluminum oxide film that can stably manufacture an aluminum oxide film with reduced thickness variation is provided. Moreover, in another side, the manufacturing raw material used suitably for the said manufacturing method and an aluminum compound are provided.
  • the present invention supplies an aluminum compound represented by the following formula (1) onto a heated film formation target, and oxidizes the aluminum compound to form an aluminum oxide film on the film formation target.
  • a method for manufacturing an aluminum oxide film which includes a forming step.
  • R represents a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R may be the same or different from each other.
  • t-Bu represents a tertiary butyl group.
  • an aluminum oxide film with reduced thickness variation can be stably manufactured.
  • the reason for this is presumably because the aluminum compound represented by the above formula (1) can be easily decomposed under heating and can stably deposit aluminum oxide into a film under heating.
  • the film formation target is preferably heated to 300 to 500 ° C. Thereby, the variation in the thickness of the aluminum oxide film can be further reduced.
  • a high-quality aluminum oxide film can be manufactured by sufficiently reducing impurities contained in the aluminum oxide film.
  • the aluminum compound may contain a compound represented by the following formula (1-1).
  • R 1 and R 2 represent different alkyl groups.
  • R 1 and R 2 each independently represent a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R 1 may be the same or different from each other.
  • t-Bu represents a tertiary butyl group.
  • the aluminum compound represented by the above formula (1-1) contains a methyl group, the vapor pressure becomes high and energy required for vaporization can be reduced.
  • an atomic layer deposition method (Atomic Layer Deposition; hereinafter referred to as “ALD method”) or a chemical vapor deposition method (Chemical Vapor Deposition method; hereinafter referred to as “CVD method”). )
  • ALD method atomic layer deposition method
  • CVD method chemical vapor deposition method
  • the present invention provides a raw material for producing an aluminum oxide film containing an aluminum compound represented by the following formula (1).
  • R represents a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R may be the same or different from each other.
  • t-Bu represents a tertiary butyl group.
  • the aluminum compound represented by the above formula (1) is used as a raw material for producing an aluminum oxide film, an aluminum oxide film with reduced thickness variation can be stably produced. This is presumably because the aluminum compound can be easily decomposed by heating in the presence of an oxygen source, and can stably deposit aluminum oxide into a film.
  • the aluminum compound may contain a compound represented by the following formula (1-1).
  • R 1 and R 2 are different alkyl groups.
  • R 1 and R 2 each independently represent a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R 1 may be the same or different from each other.
  • t-Bu represents a tertiary butyl group.
  • the aluminum compound represented by the above formula (1-1) contains a methyl group, the vapor pressure becomes high and energy required for vaporization can be reduced.
  • the present invention provides an aluminum compound represented by the following formula (1-1).
  • R 1 and R 2 represent different alkyl groups.
  • R 1 and R 2 each independently represent a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R 1 may be the same or different from each other.
  • t-Bu represents a tertiary butyl group.
  • the aluminum compound can be easily decomposed under heating, and can stably deposit aluminum oxide into a film even under heating. Therefore, an aluminum oxide film having a predetermined thickness can be stably manufactured.
  • the manufacturing raw material used suitably for the said manufacturing method and an aluminum compound can be provided.
  • the method for manufacturing an aluminum oxide film according to the present embodiment includes a step of supplying an aluminum compound onto a heated film formation target and oxidizing the aluminum compound to form the aluminum oxide film on the film formation target. Have.
  • the aluminum compound used in the method for producing an aluminum oxide film is a (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound represented by the following formula (1).
  • R represents a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R may be the same or different.
  • t-Bu represents a tertiary butyl group.
  • R (alkyl group) in formula (1) include a methyl group and an ethyl group.
  • the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound represented by the above formula (1) preferably contains a compound represented by the following formula (1-1).
  • R 1 and R 2 are different alkyl groups.
  • R 1 and R 2 each independently represents a linear alkyl group having 1 to 2 carbon atoms.
  • the two R 1 s may be the same or different from each other.
  • it is preferable that two R ⁇ 1 > is the same from a viewpoint of reduction of manufacturing cost and the ease of raw material acquisition.
  • t-Bu represents a tertiary butyl group.
  • suitable aluminum compounds used in the method for producing an aluminum oxide film include compounds represented by the following formulas (2) to (5).
  • t-Bu represents a tertiary butyl group
  • Me and Et represent a methyl group and an ethyl group, respectively. That is, the compound represented by the formula (2) is (ditertiary butyl (methyl) amidinato) dimethylaluminum, and the compound represented by the formula (3) is (ditertiary butyl (ethyl) amidinato) diethylaluminum.
  • the compound represented by the formula (4) is (ditertiary butyl (ethyl) amidinato) dimethylaluminum, and the compound represented by the formula (5) is (ditertiary butyl (methyl) amidinato) diethylaluminum.
  • Each aluminum compound represented by the above formulas (1), (1-1), (2) to (5) can be suitably used for forming an aluminum oxide film on a film formation target. That is, it is suitable for the use of forming an aluminum oxide film on a film formation target. It can also be said that the aluminum compound represented by the above formula (1), (1-1) or (2) to (5) is used for forming the aluminum oxide film.
  • dialkylaluminum compound can be produced, for example, by the following (Method 1) or (Method 2).
  • Method 1 is a method in which ditertiary butyl carbodiimide is reacted with an alkyl alkali metal compound or ditertiary butyl carbodiimide is reacted with an alkyl alkaline earth metal compound to obtain a metal salt of ditertiary butyl (alkyl) amidine.
  • One step and a second step of reacting the obtained metal salt with a dialkylaluminum halide is a method in which ditertiary butyl carbodiimide is reacted with an alkyl alkali metal compound or ditertiary butyl carbodiimide is reacted with an alkyl alkaline earth metal compound to obtain a metal salt of ditertiary butyl (alkyl) amidine.
  • Method 2 has a step of reacting ditertiary butyl carbodiimide and trialkylaluminum.
  • Examples of the metal compound used in Method 1 include methyl lithium, ethyl lithium, n-butyl lithium, s-butyl lithium, t-butyl lithium, diethyl magnesium, ethyl butyl magnesium, and dibutyl magnesium. You may use 1 type of these individually or in combination of 2 or more types. Of the above metal compounds, methyllithium is preferred from the viewpoints of reducing production costs, availability of raw materials, and improving reaction yield.
  • the amount of the alkali metal compound used is preferably 0.4 to 1.4 mol, more preferably 0.6 to 1.2 mol, with respect to 1 mol of ditertiary butylcarbodiimide.
  • the amount of the alkaline earth metal compound used is preferably 0.2 to 0.7 mol, more preferably 0.3 to 0.6 mol, with respect to 1 mol of ditertiary butylcarbodiimide.
  • dialkylaluminum halide examples include dimethylaluminum chloride, dimethylaluminum bromide, diethylaluminum chloride, and diethylaluminum bromide. You may use 1 type of these individually or in combination of 2 or more types. Of the dialkylaluminum halides, diethylaluminum chloride is preferred from the viewpoints of reducing production cost, availability of raw materials, and improving reaction yield.
  • dialkylaluminum halide used is preferably 0.1 to 1.6 mol, more preferably 0.5 mol, per 1 mol of ditertiary butyl (alkyl) amidine in the metal salt of ditertiary butyl (alkyl) amidine. ⁇ 1.2 mol.
  • trialkylaluminum used in Method 2 examples include trimethylaluminum and triethylaluminum.
  • the amount of trialkylaluminum used is preferably 0.1 to 1.6 mol, more preferably 0.5 to 1.2 mol, per 1 mol of ditertiary butylcarbodiimide.
  • Method 1 and Method 2 are each preferably performed in an organic solvent.
  • the organic solvent is not particularly limited as long as it does not inhibit the reaction. Examples include ethers such as diethyl ether, tetrahydrofuran, dimethoxyethane, and dioxane; aliphatic hydrocarbons such as hexane, heptane, cyclohexane, methylcyclohexane, and ethylcyclohexane; aromatic hydrocarbons such as toluene and xylene. Of these, ethers, aliphatic hydrocarbons, and mixed solvents of ethers and aliphatic hydrocarbons are preferable. In addition, these organic solvents may be used independently and may be used in combination of 2 or more types.
  • the amount of the organic solvent used in Method 1 and Method 2 is preferably 1 to 100 g, more preferably 5 to 50 g based on 1 g of dialkylaluminum halide or 1 g of trialkylaluminum.
  • the reaction of Method 1 can be performed, for example, by the following procedure.
  • first step ditertiary butyl carbodiimide, an alkyl alkali metal compound and an organic solvent are mixed and reacted with stirring to give an alkali metal salt of ditertiary butyl (alkyl) amidine (ditertiary butyl (alkyl) amidinato. Compound).
  • second step a dialkylaluminum halide is added and further reacted with stirring.
  • the reaction temperature in the first step and the second step is preferably ⁇ 100 to 100 ° C., more preferably ⁇ 80 to 40 ° C.
  • the reaction pressure at this time is not particularly limited.
  • the ditertiary butyl (alkyl) amidinato compound obtained in the first step may be once isolated or used as it is before the reaction with the dialkylaluminum halide in the second step.
  • the reaction of the method 2 includes, for example, a step of mixing and reacting ditertiary butylcarbodiimide, trialkylaluminum, and an organic solvent.
  • the reaction temperature at that time is preferably ⁇ 100 to 100 ° C., more preferably ⁇ 80 to 40 ° C.
  • the reaction pressure at this time is not particularly limited.
  • a dialkylaluminum compound can be obtained by the reaction of Method 1 or Method 2 (ditertiary butyl (alkyl) amidinato). After completion of the reaction, the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound may be isolated or purified by a known method. Known methods include extraction, filtration, concentration, distillation, sublimation, recrystallization, column chromatography, and the like. One of these may be used alone or in combination of two or more.
  • dialkylaluminum compounds are often unstable to moisture and oxygen in the atmosphere. For this reason, it is preferable to perform each process of Method 1 or Method 2, and post-treatment of the reaction solution as necessary under anhydrous conditions or inert gas conditions.
  • (Ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is suitably used as a production raw material (production raw material) for producing an aluminum oxide film.
  • the production raw material (production raw material) for producing the aluminum oxide film is preferably composed only of (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound.
  • the above production raw material (production raw material) is a small amount of impurities (aluminum compound, etc.) other than (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound as long as the quality of the formed aluminum oxide film is not greatly affected. ) May be included.
  • Examples of a method for forming an aluminum oxide film on a film formation target include a chemical vapor deposition method (CVD method) and an atomic layer deposition method (ALD method).
  • the ALD method is more preferably used in terms of easy control of the film thickness and easy formation of a thin film.
  • the step of forming the aluminum oxide film on the film formation target is performed, for example, according to the following procedure.
  • a gas containing (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound and a reactive gas are supplied onto the heated film formation target.
  • the reactive gas has oxygen as a constituent element. Examples thereof include oxidizing gases such as oxygen and ozone; water; alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and n-butanol.
  • the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is oxidized by the reactive gas. Thereby, aluminum oxide is vapor-deposited on the film formation target, and an aluminum oxide film is formed.
  • the gas containing (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound may be a gas (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound diluted with an inert gas or the like. Further, the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound contained in the gas may be in the form of a mist (droplet).
  • the step of forming an aluminum oxide film on the film formation target may be performed by a plasma CVD method instead of the ALD method.
  • an aluminum oxide film can be formed on the film formation target by supplying the same raw material onto the film formation target.
  • a method of vaporizing a (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound by filling or transporting it into a vaporizing chamber can be mentioned.
  • the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is diluted in a suitable solvent to prepare a solution.
  • a method (solution method) in which this solution is introduced into a vaporizing chamber with a liquid transfer pump and vaporized is exemplified.
  • solvent used here examples include aliphatic hydrocarbons such as hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, heptane, and octane; aromatic hydrocarbons such as toluene, ethylbenzene, and xylene; glyme, diglyme, triglyme, dioxane, Examples include ethers such as tetrahydrofuran. One of these may be used alone or in combination of two or more.
  • the pressure in the reaction system when forming an aluminum oxide film by vapor-depositing aluminum oxide using a (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is preferably 1 Pa to 200 kPa, more preferably 10 Pa to 110 kPa. .
  • the temperature of the film formation target when forming an aluminum oxide film using (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is preferably 200 to 600 ° C., more preferably 300 to 500 ° C. Thereby, the variation in the thickness of the aluminum oxide film can be further reduced. In addition, a high-quality aluminum oxide film can be manufactured by sufficiently reducing impurities contained in the aluminum oxide film. Further, when the temperature is 300 to 500 ° C., it is possible to suppress the change in the film thickness even if there is some variation in the temperature on the film formation target. Therefore, an aluminum oxide film having excellent film thickness uniformity can be easily manufactured.
  • the temperature at which the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is vaporized is preferably 30 to 250 ° C., more preferably 60 to 200 ° C.
  • an oxygen source for example, oxidizing gas, water vapor or alcohol vapor, or these
  • the content ratio of the reactive gas to be a mixed gas is preferably 3 to 99% by volume, more preferably 5 to 98% by volume.
  • the aluminum oxide film of this embodiment is formed on a film formation target by supplying an aluminum compound onto the heated film formation target and oxidizing the aluminum compound.
  • the aluminum oxide film has a thickness of, for example, 1 to 100 nm, preferably 5 to 50 mm.
  • the aluminum oxide film can have a satisfactory quality by sufficiently reducing the impurity concentration.
  • the content of aluminum oxide in the aluminum oxide film is, for example, 95% by mass or more, preferably 98% by mass or more, and more preferably 99% by mass or more.
  • Such a high-quality aluminum oxide film having a high purity and a small thickness is useful in the semiconductor field.
  • the aluminum oxide film may be composed only of aluminum oxide, or may be composed only of aluminum oxide and aluminum carbide. In the present specification, an aluminum oxide content of 90% by mass or more is referred to as an “aluminum oxide film”.
  • the variation in thickness of the aluminum oxide film is, for example, less than 10 nm.
  • the variation in the thickness of the aluminum oxide film is a difference in film thickness (maximum value ⁇ minimum value) measured at an arbitrarily selected location.
  • the film formation target includes a substrate containing an inorganic oxide. By forming an aluminum oxide film on such a substrate, a stacked body having the aluminum oxide film on the substrate and the substrate can be obtained.
  • (Ditertiary butyl (methyl) amidinato) dimethylaluminum is a compound in which R in the above formula (1) is a methyl group (a compound in the above formula (2)).
  • the physical properties of the obtained (ditertiary butyl (methyl) amidinato) dimethylaluminum were as follows.
  • reaction solution was concentrated, and the concentrate was distilled under reduced pressure (oil bath temperature: 80 ° C., pressure in the flask: 133.3 Pa) to give a colorless transparent liquid (ditertiary butyl (ethyl) amidinato) diethyl. 4.43 g of aluminum was obtained (isolation yield: 94%).
  • (Ditertiary butyl (ethyl) amidinato) diethylaluminum is a compound in which R in the above formula (1) is an ethyl group (compound of the above formula (3)).
  • the physical properties of the obtained (ditertiary butyl (ethyl) amidinato) diethylaluminum were as follows.
  • (Ditertiary butyl (ethyl) amidinato) dimethylaluminum is a compound of the above formula (4).
  • the physical properties of the obtained (ditertiary butyl (ethyl) amidinato) dimethylaluminum were as follows.
  • Example 5 [Production of aluminum oxide film] An aluminum oxide film was formed on the substrate by the ALD method using (ditertiary butyl (ethyl) amidinato) diethylaluminum synthesized in Example 2 as the aluminum compound, that is, the compound represented by the above formula (3). . The aluminum oxide film was formed using the apparatus shown in FIG.
  • the apparatus shown in FIG. 1 includes a vaporizer 1 (SUS ampule) that vaporizes an aluminum compound 2, a vaporizer 6 (SUS ampule) that vaporizes water 7 and supplies water vapor as a reactive gas, and a substrate 15. And a reactor 11 having a heater 14 for heating the substrate 15 and reacting the aluminum compound 2 with water vapor to form an aluminum oxide film on the substrate 15.
  • a vacuum pump is connected to the reactor 11 via a flow path.
  • a pressure gauge 13, a pressure control valve 12 and a trap 16 are provided in the flow path. Thereby, the pressure in the reactor 11 is adjusted to a predetermined range. The gas led out from the reactor 11 is exhausted to the atmosphere through the trap 16 and the vacuum pump.
  • the aluminum compound 2 and the water 7 synthesized in Example 2 were accommodated in the vaporizer 1 and the vaporizer 6 respectively including the heater 3 and the constant temperature bath 8.
  • the vaporizer 1 was supplied with argon gas whose flow rate was adjusted by the mass flow controller 4 and preheated by the preheater 5. As a result, argon gas containing the aluminum compound 2 was introduced into the reactor 11 from the vaporizer 1.
  • water vapor that was vaporized by being adjusted to a constant temperature by the thermostatic chamber 8 was introduced into the reactor 11 from the vaporizer 6.
  • the argon gas containing the aluminum compound 2 from the vaporizer 1 and the water vapor from the vaporizer 6 were alternately introduced into the reactor 11.
  • the introduction amounts of argon gas and water vapor containing the aluminum compound 2 were adjusted by a valve 17 and a valve 18, respectively.
  • the argon gas and water vapor containing the aluminum compound 2 were each adjusted in flow rate by the mass flow controller 9 and introduced into the reactor 11 along with the dilution argon gas preheated by the preheater 10.
  • Aluminum compound 2 and water 7 were alternately supplied to the reactor 11 to form an aluminum oxide film 20 on the substrate 15 heated to a predetermined temperature by the heater 14.
  • the operating conditions of the apparatus of FIG. 1 were as follows.
  • the vaporization temperature of the aluminum compound 2 (vaporizer 1): 90 ° C Ar gas (carrier gas) flow rate: 5 mL / min (adjusted with mass flow controller 4)
  • Aluminum compound 2 supply time 1 second
  • Aluminum compound 2 purge time 5 seconds
  • Water 7 vaporization temperature 10 ° C.
  • Water 7 supply time 1 second
  • Ar gas flow rate for dilution 50 mL / min.
  • Material of substrate 15: SiO 2 / Si Size of substrate 15: vertical x horizontal 20 mm x 20 mm
  • the temperature of the substrate 15 300 ° C. Pressure in the reactor 11: 1333 Pa Number of cycles: 500 times (introduction of argon gas containing aluminum compound 2 and introduction of water vapor from the vaporizer 6 were repeated 500 times)
  • the aluminum oxide film 20 was formed on the substrate 15 under the above conditions.
  • the thickness of the formed aluminum oxide film 20 was measured using a reflection spectral film thickness meter.
  • the composition of the aluminum oxide film 20 was analyzed using an XPS (X-ray photoelectron spectroscopy) measuring apparatus. The results of thickness and composition analysis were as shown in Table 1.
  • the thickness of the aluminum oxide film 20 was performed at five arbitrarily selected locations, and the maximum value and the minimum value were obtained.
  • the maximum value ⁇ the minimum value ⁇ 10 nm the arithmetic average value is shown in the table.
  • the maximum value ⁇ minimum value ⁇ 10 nm the maximum value and the minimum value were shown.
  • Example 6 to 10 [Production of aluminum oxide film] An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that the temperature of the substrate 15 was changed as shown in Table 1. The analysis results of the thickness and composition of the formed aluminum oxide film 20 were as shown in Table 1.
  • the aluminum oxide films of Examples 5 to 10 had no thickness variation and excellent thickness uniformity. Further, it was confirmed that when the temperature of the substrate 15 is in the range of 300 to 500 ° C., the thickness of the aluminum oxide film does not change much. From this, it was confirmed that the aluminum oxide film can be formed stably by using (ditertiary butyl (ethyl) amidinato) diethylaluminum synthesized in Example 2.
  • the aluminum oxide content in the aluminum oxide film of Example 10 was 95% by mass or more, and the aluminum carbide content was 5% by mass or less.
  • Example 11 [Production of aluminum oxide film]
  • the aluminum compound (ditertiary butyl (methyl) amidinato) diethylaluminum synthesized in Example 3, that is, the compound represented by the above formula (5) was used.
  • An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that this aluminum compound was used and the vaporization temperature of the aluminum compound in the vaporizer 1 was set to 80 ° C.
  • the analysis results of the thickness and composition of the formed aluminum oxide film 20 were as shown in Table 2.
  • Example 12 to 16 [Production of aluminum oxide film] An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 11 except that the temperature of the substrate 15 was changed as shown in Table 2. The analysis results of the thickness and composition of the formed aluminum oxide film 20 were as shown in Table 2.
  • the aluminum oxide films of Examples 11 to 16 had no thickness variation and were excellent in thickness uniformity. Further, it was confirmed that when the temperature of the substrate 15 is in the range of 300 to 500 ° C., the thickness of the aluminum oxide film does not change much. From this, it was confirmed that by using (ditertiary butyl (methyl) amidinato) diethylaluminum synthesized in Example 3, an aluminum oxide film can be formed stably.
  • Example 17 [Production of aluminum oxide film]
  • the aluminum compound (ditertiary butyl (ethyl) amidinato) dimethylaluminum synthesized in Example 4, that is, the compound represented by the formula (4) was used.
  • An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that this aluminum compound was used and the vaporization temperature of the aluminum compound in the vaporizer 1 was set to 70 ° C.
  • the analysis results of the thickness and composition of the formed aluminum oxide film 20 are as shown in Table 3.
  • Example 18 to 20 [Production of aluminum oxide film] An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 17 except that the temperature of the substrate 15 was changed as shown in Table 3. The analysis results of the thickness and composition of the formed aluminum oxide film 20 are as shown in Table 3.
  • the aluminum oxide films of Examples 17 to 20 had no thickness variation and excellent thickness uniformity. Further, it was confirmed that the thickness of the aluminum oxide film did not change when the temperature of the substrate 15 was in the range of 300 to 500 ° C. From this, it was confirmed that the aluminum oxide film can be stably formed by using (ditertiary butyl (ethyl) amidinato) dimethylaluminum synthesized in Example 4.
  • Example 21 [Production of aluminum oxide film]
  • the aluminum compound (ditertiary butyl (methyl) amidinato) dimethylaluminum synthesized in Example 1, that is, the compound represented by the formula (2) was used.
  • An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that this aluminum compound was used and the vaporization temperature of the aluminum compound in the vaporizer 1 was set to 70 ° C.
  • the analysis results of the thickness and composition of the formed aluminum oxide film 20 are as shown in Table 4.
  • Example 22 to 24 [Production of aluminum oxide film] An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 21 except that the temperature of the substrate 15 was changed as shown in Table 4. The analysis results of the thickness and composition of the formed aluminum oxide film 20 are as shown in Table 4.
  • the aluminum oxide films of Examples 21 to 24 had no thickness variation and were excellent in thickness uniformity. Further, it was confirmed that the thickness of the aluminum oxide film did not change when the temperature of the substrate 15 was in the range of 300 to 500 ° C. From this, it was confirmed that the aluminum oxide film can be stably formed by using the ditertiary butyl (methyl) amidinato) dimethylaluminum synthesized in Example 1.
  • reaction solution was concentrated, and the concentrate was distilled under reduced pressure (oil bath temperature 70 ° C., pressure in the flask: 133.3 Pa) to obtain 4.94 g of a transparent liquid (diisopropyl (methyl) amidinato) dimethylaluminum. Obtained (isolation yield: 90% by mass).
  • (Diisopropyl (methyl) amidinato) dimethylaluminum is represented by the following chemical formula.
  • the physical properties of the obtained (diisopropyl (methyl) amidinato) dimethylaluminum were as follows.
  • the obtained concentrate was distilled under reduced pressure (oil bath temperature 90 ° C., pressure in the flask: 133.3 Pa) to obtain 3.02 g of (dimethylamido) diethylaluminum as a transparent liquid (isolated yield: 82% by mass). ).
  • the thickness variation of the aluminum oxide film of Comparative Example 5 was small.
  • the aluminum compounds represented by the above formulas (2) to (5) used in the above examples were sufficiently excellent in safety. Further, since the aluminum thin film was formed under the above conditions, the aluminum compounds represented by the formulas (2) to (5) had good reactivity with the reactive gas. It has also been found that the vapor containing the aluminum compound represented by the above formulas (2) to (5) has excellent adsorptivity to the substrate surface. Furthermore, by setting the temperature of the substrate to 300 to 500 ° C., an aluminum oxide film with high aluminum oxide purity can be formed while reducing the change in thickness. That is, a high quality aluminum oxide film can be manufactured.
  • a method for producing an aluminum oxide film capable of stably producing an aluminum oxide film with reduced thickness variation. Production raw materials and aluminum compounds that are suitably used in the production method are provided.

Abstract

Provided is a method for producing aluminum oxide film, including the step of forming an aluminum oxide film on the film-forming target by providing an aluminum compound represented by formula (1) on a heated film-forming target and oxidizing the aluminum compound. In formula (1), R represents a linear alkyl group having 1 to 2 carbon atoms, and multiple instances of R may be the same or different. t-Bu represents a tertiary butyl group.

Description

酸化アルミニウム膜の製造方法、酸化アルミニウム膜の製造原料、及びアルミニウム化合物Aluminum oxide film manufacturing method, aluminum oxide film manufacturing raw material, and aluminum compound
　本開示は、酸化アルミニウム膜の製造方法、酸化アルミニウム膜の製造原料、及びアルミニウム化合物に関する。 The present disclosure relates to a method for manufacturing an aluminum oxide film, a raw material for manufacturing an aluminum oxide film, and an aluminum compound.
　酸化アルミニウム膜は、ゲート絶縁膜等として有用であり、半導体分野において幅広く応用展開がなされている。そこで、酸化アルミニウム膜を製造するためのアルミニウム化合物（酸化アルミニウム膜の製造原料）が検討されている（例えば、特許文献１～４参照）。 The aluminum oxide film is useful as a gate insulating film and has been widely applied in the semiconductor field. Therefore, an aluminum compound (a raw material for producing an aluminum oxide film) for producing an aluminum oxide film has been studied (see, for example, Patent Documents 1 to 4).
　一方で、非特許文献１には、重合触媒として（ジターシャリーブチル（メチル）アミジナト）ジメチルアルミニウムが開示されている。しかしながら、物性値及び特性については何ら記載されていない。また、非特許文献２には、（ジターシャリーブチル（エチル）アミジナト）ジエチルアルミニウムの合成例が開示されている。しかしながら、特性については何ら記載されていない。 On the other hand, Non-Patent Document 1 discloses (ditertiary butyl (methyl) amidinato) dimethylaluminum as a polymerization catalyst. However, no physical property values and characteristics are described. Non-Patent Document 2 discloses a synthesis example of (ditertiary butyl (ethyl) amidinato) diethylaluminum. However, no properties are described.
特表２００６－５２６７０５号公報JP 2006-526705 A 特許第４７１６１９３号公報Japanese Patent No. 4716193 特開２００７－１３８２９６号公報JP 2007-138296 A 韓国登録特許第１０－１２２１８６１号公報Korean Registered Patent No. 10-121861
　酸化アルミニウム膜を安定的に製造し得る新たな酸化アルミニウム膜の製造方法が求められている。 There is a need for a new method for producing an aluminum oxide film that can stably produce an aluminum oxide film.
　そこで、本開示では、一つの側面において、厚みのばらつきが低減された酸化アルミニウム膜を安定的に製造し得る酸化アルミニウム膜の製造方法を提供する。また、別の側面において、当該製造方法に好適に用いられる製造原料、及びアルミニウム化合物を提供する。 Therefore, in one aspect of the present disclosure, a method for manufacturing an aluminum oxide film that can stably manufacture an aluminum oxide film with reduced thickness variation is provided. Moreover, in another side, the manufacturing raw material used suitably for the said manufacturing method and an aluminum compound are provided.
　本発明は、一つの側面において、加熱されている成膜対象物上に下記式（１）で示されるアルミニウム化合物を供給し、アルミニウム化合物を酸化することにより成膜対象物上に酸化アルミニウム膜を形成する工程を有する、酸化アルミニウム膜の製造方法を提供する。 In one aspect, the present invention supplies an aluminum compound represented by the following formula (1) onto a heated film formation target, and oxidizes the aluminum compound to form an aluminum oxide film on the film formation target. Provided is a method for manufacturing an aluminum oxide film, which includes a forming step.
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
　上式（１）中、Ｒは炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲは互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。） In the above formula (1), R represents a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R may be the same or different from each other. t-Bu represents a tertiary butyl group. )
　上記製造方法では、厚みのばらつきが低減された酸化アルミニウム膜を安定的に製造することができる。この理由は、上記式（１）で表されるアルミニウム化合物が、加熱下で容易に分解できるとともに、加熱下で安定的に酸化アルミニウムを膜状に析出できるためであると推察される。 In the above manufacturing method, an aluminum oxide film with reduced thickness variation can be stably manufactured. The reason for this is presumably because the aluminum compound represented by the above formula (1) can be easily decomposed under heating and can stably deposit aluminum oxide into a film under heating.
　幾つかの実施形態において、上記成膜対象物は３００～５００℃に加熱されていることが好ましい。これによって、酸化アルミニウム膜の厚みのばらつきを一層低減することができる。また、酸化アルミニウム膜に含まれる不純物を十分に低減して、高品位な酸化アルミニウム膜を製造することができる。 In some embodiments, the film formation target is preferably heated to 300 to 500 ° C. Thereby, the variation in the thickness of the aluminum oxide film can be further reduced. In addition, a high-quality aluminum oxide film can be manufactured by sufficiently reducing impurities contained in the aluminum oxide film.
　上記アルミニウム化合物は、下記式（１－１）で示される化合物を含んでいてもよい。 The aluminum compound may contain a compound represented by the following formula (1-1).
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000007
　上式（１－１）中、Ｒ１及びＲ２は互いに異なるアルキル基を示す。Ｒ１及びＲ２は、それぞれ独立に炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲ１は互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。 In the above formula (1-1), R 1 and R 2 represent different alkyl groups. R 1 and R 2 each independently represent a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R 1 may be the same or different from each other. t-Bu represents a tertiary butyl group.
　上式（１－１）で示されるアルミニウム化合物は、メチル基を含むことによって、蒸気圧が高くなり、気化させる際に必要なエネルギーを低減することができる。 When the aluminum compound represented by the above formula (1-1) contains a methyl group, the vapor pressure becomes high and energy required for vaporization can be reduced.
　上記工程では、原子層堆積法（Ａｔｏｍｉｃ　Ｌａｙｅｒ　Ｄｅｐｏｓｉｔｉｏｎ；以下、「ＡＬＤ法」と称することもある。）又は化学気相蒸着法（Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ法；以下、「ＣＶＤ法」と称することもある。）により酸化アルミニウム膜を形成することが好ましい。これによって、一層高品位な酸化アルミニウム膜を形成することができる。 In the above process, an atomic layer deposition method (Atomic Layer Deposition; hereinafter referred to as “ALD method”) or a chemical vapor deposition method (Chemical Vapor Deposition method; hereinafter referred to as “CVD method”). ) To form an aluminum oxide film. Thereby, a higher quality aluminum oxide film can be formed.
　本発明は、別の側面において、下記式（１）で示されるアルミニウム化合物を含む、酸化アルミニウム膜の製造原料を提供する。 In another aspect, the present invention provides a raw material for producing an aluminum oxide film containing an aluminum compound represented by the following formula (1).
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000008
　上式（１）中、Ｒは炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲは互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。 In the above formula (1), R represents a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R may be the same or different from each other. t-Bu represents a tertiary butyl group.
　上記式（１）で表されるアルミニウム化合物を酸化アルミニウム膜の製造原料として用いる方法であれば、厚みのばらつきが低減された酸化アルミニウム膜を安定的に製造することができる。この理由は、上記アルミニウム化合物が、酸素源の存在下、加熱することにより容易に分解できるとともに、安定的に酸化アルミニウムを膜状に析出することができるためと推察される。 If the aluminum compound represented by the above formula (1) is used as a raw material for producing an aluminum oxide film, an aluminum oxide film with reduced thickness variation can be stably produced. This is presumably because the aluminum compound can be easily decomposed by heating in the presence of an oxygen source, and can stably deposit aluminum oxide into a film.
　上記アルミニウム化合物は、下記式（１－１）で示される化合物を含んでいてもよい。 The aluminum compound may contain a compound represented by the following formula (1-1).
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000009
　上式（１－１）中、Ｒ１及びＲ２は互いに異なるアルキル基である。Ｒ１及びＲ２は、それぞれ独立に炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲ１は互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。） In the above formula (1-1), R 1 and R 2 are different alkyl groups. R 1 and R 2 each independently represent a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R 1 may be the same or different from each other. t-Bu represents a tertiary butyl group. )
　上式（１－１）で示されるアルミニウム化合物は、メチル基を含むことによって、蒸気圧が高くなり、気化させる際に必要なエネルギーを低減することができる。 When the aluminum compound represented by the above formula (1-1) contains a methyl group, the vapor pressure becomes high and energy required for vaporization can be reduced.
　本発明は、さらに別の側面において、下記の式（１－１）で示される、アルミニウム化合物を提供する。 In yet another aspect, the present invention provides an aluminum compound represented by the following formula (1-1).
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000010
　式（１－１）中、Ｒ１及びＲ２は互いに異なるアルキル基を示す。Ｒ１及びＲ２は、それぞれ独立に炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲ１は互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。 In formula (1-1), R 1 and R 2 represent different alkyl groups. R 1 and R 2 each independently represent a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R 1 may be the same or different from each other. t-Bu represents a tertiary butyl group.
　上記アルミニウム化合物は、加熱下で容易に分解できるとともに、加熱下でも安定的に酸化アルミニウムを膜状に析出することができる。したがって、所定の厚みを有する酸化アルミニウム膜を安定的に製造することができる。 The aluminum compound can be easily decomposed under heating, and can stably deposit aluminum oxide into a film even under heating. Therefore, an aluminum oxide film having a predetermined thickness can be stably manufactured.
　本開示では、一つの側面において、厚みのばらつきが低減された酸化アルミニウム膜を安定的に製造し得る酸化アルミニウム膜の製造方法を提供することができる。また、別の側面において、当該製造方法に好適に用いられる製造原料、及びアルミニウム化合物を提供することができる。 In one aspect of the present disclosure, it is possible to provide a method for manufacturing an aluminum oxide film that can stably manufacture an aluminum oxide film with reduced thickness variation. Moreover, in another side, the manufacturing raw material used suitably for the said manufacturing method and an aluminum compound can be provided.
酸化アルミニウム膜の製造装置の模式図である。It is a schematic diagram of the manufacturing apparatus of an aluminum oxide film.
　本発明の一実施形態を以下に説明する。本実施形態の酸化アルミニウム膜の製造方法は、加熱されている成膜対象物上にアルミニウム化合物を供給し、当該アルミニウム化合物を酸化することにより成膜対象物上に酸化アルミニウム膜を形成する工程を有する。 One embodiment of the present invention will be described below. The method for manufacturing an aluminum oxide film according to the present embodiment includes a step of supplying an aluminum compound onto a heated film formation target and oxidizing the aluminum compound to form the aluminum oxide film on the film formation target. Have.
　酸化アルミニウム膜の製造方法に使用されるアルミニウム化合物は、下記式（１）で示される（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物である。 The aluminum compound used in the method for producing an aluminum oxide film is a (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound represented by the following formula (1).
Figure JPOXMLDOC01-appb-C000011
Figure JPOXMLDOC01-appb-C000011
　上式（１）中、Ｒは炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲは同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。式（１）中のＲ（アルキル基）としては、例えば、メチル基、エチル基が挙げられる。 In the above formula (1), R represents a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R may be the same or different. t-Bu represents a tertiary butyl group. Examples of R (alkyl group) in formula (1) include a methyl group and an ethyl group.
　上記式（１）で示される（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物は、下記式（１－１）に示される化合物を含むことが好ましい。 The (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound represented by the above formula (1) preferably contains a compound represented by the following formula (1-1).
Figure JPOXMLDOC01-appb-C000012
Figure JPOXMLDOC01-appb-C000012
　上式（１－１）中、Ｒ１及びＲ２は互いに異なるアルキル基である。Ｒ１及びＲ２は、それぞれ独立に炭素原子数１～２の直鎖状のアルキル基を示す。ふたつのＲ１は互いに同一又は異なっていてもよい。ただし、製造コストの低減、原料入手の容易性の観点から、ふたつのＲ１は同一であることが好ましい。ｔ－Ｂｕはターシャリーブチル基を示す。 In the above formula (1-1), R 1 and R 2 are different alkyl groups. R 1 and R 2 each independently represents a linear alkyl group having 1 to 2 carbon atoms. The two R 1 s may be the same or different from each other. However, it is preferable that two R < 1 > is the same from a viewpoint of reduction of manufacturing cost and the ease of raw material acquisition. t-Bu represents a tertiary butyl group.
　酸化アルミニウム膜の製造方法に使用されるアルミニウム化合物の好適な具体例としては、下記式（２）～（５）で示される化合物が挙げられる。 Specific examples of suitable aluminum compounds used in the method for producing an aluminum oxide film include compounds represented by the following formulas (2) to (5).
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000013
　下記式（２）～（５）におけるｔ－Ｂｕはターシャリーブチル基を示し、Ｍｅ及びＥｔはそれぞれメチル基及びエチル基を示す。すなわち、式（２）で示される化合物は、（ジターシャリーブチル（メチル）アミジナト）ジメチルアルミニウムであり、式（３）で示される化合物は、（ジターシャリーブチル（エチル）アミジナト）ジエチルアルミニウムである。式（４）で示される化合物は、（ジターシャリーブチル（エチル）アミジナト）ジメチルアルミニウムであり、式（５）で示される化合物は、（ジターシャリーブチル（メチル）アミジナト）ジエチルアルミニウムである。 In the following formulas (2) to (5), t-Bu represents a tertiary butyl group, and Me and Et represent a methyl group and an ethyl group, respectively. That is, the compound represented by the formula (2) is (ditertiary butyl (methyl) amidinato) dimethylaluminum, and the compound represented by the formula (3) is (ditertiary butyl (ethyl) amidinato) diethylaluminum. The compound represented by the formula (4) is (ditertiary butyl (ethyl) amidinato) dimethylaluminum, and the compound represented by the formula (5) is (ditertiary butyl (methyl) amidinato) diethylaluminum.
　上記式（１）、（１－１）、（２）～（５）で示される各アルミニウム化合物は、成膜対象物上に酸化アルミニウム膜を形成するために好適に使用することができる。すなわち、成膜対象物上における酸化アルミニウム膜の形成用途に適している。酸化アルミニウム膜を形成するための上記式（１）、（１－１）又は（２）～（５）で示されるアルミニウム化合物の使用ということもできる。 Each aluminum compound represented by the above formulas (1), (1-1), (2) to (5) can be suitably used for forming an aluminum oxide film on a film formation target. That is, it is suitable for the use of forming an aluminum oxide film on a film formation target. It can also be said that the aluminum compound represented by the above formula (1), (1-1) or (2) to (5) is used for forming the aluminum oxide film.
　（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物は、例えば、下記の（方法１）又は（方法２）等によって製造することができる。 (Ditertiary butyl (alkyl) amidinato) dialkylaluminum compound can be produced, for example, by the following (Method 1) or (Method 2).
　方法１は、ジターシャリーブチルカルボジイミドとアルキルアルカリ金属化合物とを反応させて、又はジターシャリーブチルカルボジイミドとアルキルアルカリ土類金属化合物とを反応させて、ジターシャリーブチル（アルキル）アミジンの金属塩を得る第１工程と、得られた金属塩とジアルキルアルミニウムハライドとを反応させる第２工程と、を有する。 Method 1 is a method in which ditertiary butyl carbodiimide is reacted with an alkyl alkali metal compound or ditertiary butyl carbodiimide is reacted with an alkyl alkaline earth metal compound to obtain a metal salt of ditertiary butyl (alkyl) amidine. One step and a second step of reacting the obtained metal salt with a dialkylaluminum halide.
　方法２は、ジターシャリーブチルカルボジイミドとトリアルキルアルミニウムとを反応させる工程を有する。 Method 2 has a step of reacting ditertiary butyl carbodiimide and trialkylaluminum.
　方法１において使用する金属化合物としては、例えば、メチルリチウム、エチルリチウム、ｎ－ブチルリチウム、ｓ－ブチルリチウム、ｔ－ブチルリチウム、ジエチルマグネシウム、エチルブチルマグネシウム、及びジブチルマグネシウム等が挙げられる。これらのうちの一種を単独で又は二種以上を組み合わせて用いてもよい。上記金属化合物のうち、製造コストの低減、原料の入手容易性、反応収率向上の観点から、好ましくはメチルリチウムである。 Examples of the metal compound used in Method 1 include methyl lithium, ethyl lithium, n-butyl lithium, s-butyl lithium, t-butyl lithium, diethyl magnesium, ethyl butyl magnesium, and dibutyl magnesium. You may use 1 type of these individually or in combination of 2 or more types. Of the above metal compounds, methyllithium is preferred from the viewpoints of reducing production costs, availability of raw materials, and improving reaction yield.
　アルカリ金属化合物の使用量は、ジターシャリーブチルカルボジイミド１モルに対して、好ましくは０．４～１．４モル、より好ましくは０．６～１．２モルである。また、アルカリ土類金属化合物の使用量は、ジターシャリーブチルカルボジイミド１モルに対して、好ましくは０．２～０．７モル、より好ましくは０．３～０．６モルである。 The amount of the alkali metal compound used is preferably 0.4 to 1.4 mol, more preferably 0.6 to 1.2 mol, with respect to 1 mol of ditertiary butylcarbodiimide. The amount of the alkaline earth metal compound used is preferably 0.2 to 0.7 mol, more preferably 0.3 to 0.6 mol, with respect to 1 mol of ditertiary butylcarbodiimide.
　方法１において使用するジアルキルアルミニウムハライドとしては、例えば、ジメチルアルミニウムクロライド、ジメチルアルミニウムブロマイド、ジエチルアルミニウムクロライド、及びジエチルアルミニウムブロマイド等が挙げられる。これらのうちの一種を単独で又は二種以上を組み合わせて用いてもよい。上記ジアルキルアルミニウムハライドのうち、製造コストの低減、原料の入手容易性、及び反応収率向上の観点から、好ましくはジエチルアルミニウムクロライドである。 Examples of the dialkylaluminum halide used in Method 1 include dimethylaluminum chloride, dimethylaluminum bromide, diethylaluminum chloride, and diethylaluminum bromide. You may use 1 type of these individually or in combination of 2 or more types. Of the dialkylaluminum halides, diethylaluminum chloride is preferred from the viewpoints of reducing production cost, availability of raw materials, and improving reaction yield.
　ジアルキルアルミニウムハライドの使用量は、ジターシャリーブチル（アルキル）アミジンの金属塩中のジターシャリーブチル（アルキル）アミジン１モルに対して、好ましくは０．１～１．６モル、より好ましくは０．５～１．２モルである。 The amount of dialkylaluminum halide used is preferably 0.1 to 1.6 mol, more preferably 0.5 mol, per 1 mol of ditertiary butyl (alkyl) amidine in the metal salt of ditertiary butyl (alkyl) amidine. ~ 1.2 mol.
　方法２において使用するトリアルキルアルミニウムは、トリメチルアルミニウム及びトリエチルアルミニウム等が挙げられる。 Examples of the trialkylaluminum used in Method 2 include trimethylaluminum and triethylaluminum.
　トリアルキルアルミニウムの使用量は、ジターシャリーブチルカルボジイミド１モルに対して、好ましくは０．１～１．６モル、より好ましくは０．５～１．２モルである。 The amount of trialkylaluminum used is preferably 0.1 to 1.6 mol, more preferably 0.5 to 1.2 mol, per 1 mol of ditertiary butylcarbodiimide.
　方法１及び方法２は、それぞれ、有機溶媒中で行うことが好ましい。有機溶媒としては、反応を阻害しないものであれば特に限定されない。例えば、ジエチルエーテル、テトラヒドロフラン、ジメトキシエタン、ジオキサン等のエーテル類；ヘキサン、ヘプタン、シクロヘキサン、メチルシクロヘキサン、エチルシクロヘキサン等の脂肪族炭化水素類；トルエン、キシレン等の芳香族炭化水素類が挙げられる。これらのうち、好ましくはエーテル類、脂肪族炭化水素類、エーテル類と脂肪族炭化水素類との混合溶媒である。なお、これらの有機溶媒は単独で使用してもよいし、二種以上を組み合わせて使用してもよい。 Method 1 and Method 2 are each preferably performed in an organic solvent. The organic solvent is not particularly limited as long as it does not inhibit the reaction. Examples include ethers such as diethyl ether, tetrahydrofuran, dimethoxyethane, and dioxane; aliphatic hydrocarbons such as hexane, heptane, cyclohexane, methylcyclohexane, and ethylcyclohexane; aromatic hydrocarbons such as toluene and xylene. Of these, ethers, aliphatic hydrocarbons, and mixed solvents of ethers and aliphatic hydrocarbons are preferable. In addition, these organic solvents may be used independently and may be used in combination of 2 or more types.
　方法１及び方法２における有機溶媒の使用量は、ジアルキルアルミニウムハライド１ｇ又はトリアルキルアルミニウム１ｇに対して、好ましくは１～１００ｇ、更に好ましくは５～５０ｇである。 The amount of the organic solvent used in Method 1 and Method 2 is preferably 1 to 100 g, more preferably 5 to 50 g based on 1 g of dialkylaluminum halide or 1 g of trialkylaluminum.
　（方法１による合成方法）
　方法１の反応は、例えば、次の手順で行うことができる。最初の工程（第１工程）でジターシャリーブチルカルボジイミド、アルキルアルカリ金属化合物及び有機溶媒を混合し、攪拌しながら反応させてジターシャリーブチル（アルキル）アミジンのアルカリ金属塩（ジターシャリーブチル（アルキル）アミジナト化合物）を合成する。次の工程（第２工程）で、ジアルキルアルミニウムハライドを加えて、更に攪拌しながら反応させる。第１工程及び第２工程における反応温度は、好ましくは－１００～１００℃、より好ましくは－８０～４０℃である。このときの反応圧力は特に制限されない。なお、第１工程で得られるジターシャリーブチル（アルキル）アミジナト化合物は、第２工程におけるジアルキルアルミニウムハライドとの反応前に、一旦単離してもよいし、そのまま使用してもよい。 (Synthesis method by Method 1)
The reaction of Method 1 can be performed, for example, by the following procedure. In the first step (first step), ditertiary butyl carbodiimide, an alkyl alkali metal compound and an organic solvent are mixed and reacted with stirring to give an alkali metal salt of ditertiary butyl (alkyl) amidine (ditertiary butyl (alkyl) amidinato. Compound). In the next step (second step), a dialkylaluminum halide is added and further reacted with stirring. The reaction temperature in the first step and the second step is preferably −100 to 100 ° C., more preferably −80 to 40 ° C. The reaction pressure at this time is not particularly limited. In addition, the ditertiary butyl (alkyl) amidinato compound obtained in the first step may be once isolated or used as it is before the reaction with the dialkylaluminum halide in the second step.
　（方法２による合成方法）
　方法２の反応は、例えば、ジターシャリーブチルカルボジイミド、トリアルキルアルミニウム及び有機溶媒を混合し反応させる工程を有する。その際の反応温度は、好ましくは－１００～１００℃、より好ましくは－８０～４０℃である。このときの反応圧力は特に制限されない。 (Synthesis method by Method 2)
The reaction of the method 2 includes, for example, a step of mixing and reacting ditertiary butylcarbodiimide, trialkylaluminum, and an organic solvent. The reaction temperature at that time is preferably −100 to 100 ° C., more preferably −80 to 40 ° C. The reaction pressure at this time is not particularly limited.
　方法１又は方法２の反応により（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を得ることができる。反応終了後、（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物は、公知の方法によって単離又は精製してもよい。公知の方法としては、抽出、濾過、濃縮、蒸留、昇華、再結晶及びカラムクロマトグラフィー等が挙げられる。これらのうちの一種を単独で又は二種以上を組み合わせてもよい。 A dialkylaluminum compound can be obtained by the reaction of Method 1 or Method 2 (ditertiary butyl (alkyl) amidinato). After completion of the reaction, the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound may be isolated or purified by a known method. Known methods include extraction, filtration, concentration, distillation, sublimation, recrystallization, column chromatography, and the like. One of these may be used alone or in combination of two or more.
　（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物は、大気中の水分及び酸素に対して不安定な場合が多い。このため、無水条件下又は不活性ガス条件下にて、方法１又は方法２の各工程、及び必要に応じて反応液の後処理等を行うことが好ましい。 (Ditertiary butyl (alkyl) amidinato) dialkylaluminum compounds are often unstable to moisture and oxygen in the atmosphere. For this reason, it is preferable to perform each process of Method 1 or Method 2, and post-treatment of the reaction solution as necessary under anhydrous conditions or inert gas conditions.
　（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物は、酸化アルミニウム膜を製造するための製造原料（製造用原料）として好適に使用される。酸化アルミニウム膜を製造するための製造原料（製造用原料）は、（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物のみからなることが好ましい。ただし、上記製造原料（製造用原料）は、形成される酸化アルミニウム膜の品質に大きな影響を及ぼさない範囲で、（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物以外の少量の不純物（アルミニウム化合物等）を含んでもよい。 (Ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is suitably used as a production raw material (production raw material) for producing an aluminum oxide film. The production raw material (production raw material) for producing the aluminum oxide film is preferably composed only of (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound. However, the above production raw material (production raw material) is a small amount of impurities (aluminum compound, etc.) other than (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound as long as the quality of the formed aluminum oxide film is not greatly affected. ) May be included.
　成膜対象物上への酸化アルミニウム膜の形成方法としては、例えば、化学気相蒸着法（ＣＶＤ法）及び原子層堆積法（ＡＬＤ法）が挙げられる。これらのうち、膜厚を制御しやすく、薄膜の成膜が容易である点で、ＡＬＤ法がより好ましく用いられる。ＡＬＤ法の場合、成膜対象物上に酸化アルミニウム膜を形成する工程は、例えば以下の手順で行われる。 Examples of a method for forming an aluminum oxide film on a film formation target include a chemical vapor deposition method (CVD method) and an atomic layer deposition method (ALD method). Among these, the ALD method is more preferably used in terms of easy control of the film thickness and easy formation of a thin film. In the case of the ALD method, the step of forming the aluminum oxide film on the film formation target is performed, for example, according to the following procedure.
　常圧又は減圧下にて、（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を含むガスと、反応性ガスとを、加熱した成膜対象物上に供給する。反応性ガスは、構成元素として酸素を有する。例えば、酸素、オゾン等の酸化性ガス；水；メタノール、エタノール、ｎ－プロピルアルコール、イソプロピルアルコール、ｎ－ブタノール等のアルコール類が挙げられる。上記反応性ガスによって、（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を酸化する。これによって、成膜対象物上に酸化アルミニウムが蒸着され、酸化アルミニウム膜が形成される。 Under normal pressure or reduced pressure, a gas containing (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound and a reactive gas are supplied onto the heated film formation target. The reactive gas has oxygen as a constituent element. Examples thereof include oxidizing gases such as oxygen and ozone; water; alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and n-butanol. The (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is oxidized by the reactive gas. Thereby, aluminum oxide is vapor-deposited on the film formation target, and an aluminum oxide film is formed.
　（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を含むガスは、ガス状の（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物が不活性ガス等で希釈されたものであってもよい。また、ガスに含まれる（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物は、霧状（液滴状）であってもよい。 The gas containing (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound may be a gas (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound diluted with an inert gas or the like. Further, the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound contained in the gas may be in the form of a mist (droplet).
　ＡＬＤ法の代わりにプラズマＣＶＤ法によって、成膜対象物上に酸化アルミニウム膜を形成する工程を行ってもよい。この場合、同様の原料を成膜対象物上に供給して、酸化アルミニウム膜を成膜対象物上に形成することができる。 The step of forming an aluminum oxide film on the film formation target may be performed by a plasma CVD method instead of the ALD method. In this case, an aluminum oxide film can be formed on the film formation target by supplying the same raw material onto the film formation target.
　ＣＶＤ法の場合、薄膜（酸化アルミニウム膜）形成のために（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を気化させる必要がある。（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を気化させる方法としては、例えば、次のような方法が挙げられる。 In the case of the CVD method, it is necessary to vaporize (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound in order to form a thin film (aluminum oxide film). Examples of the method for vaporizing the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound include the following methods.
　すなわち、（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を気化室に充填又は搬送して気化させる方法が挙げられる。別の方法としては、（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を適当な溶媒に希釈して溶液を調製する。この溶液を液体搬送用ポンプで気化室に導入して気化させる方法（溶液法）が挙げられる。 That is, a method of vaporizing a (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound by filling or transporting it into a vaporizing chamber can be mentioned. Alternatively, the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is diluted in a suitable solvent to prepare a solution. A method (solution method) in which this solution is introduced into a vaporizing chamber with a liquid transfer pump and vaporized is exemplified.
　ここで用いられる溶媒としては、ヘキサン、シクロヘキサン、メチルシクロヘキサン、エチルシクロヘキサン、ヘプタン、オクタン等の脂肪族炭化水素類；トルエン、エチルベンゼン、キシレン等の芳香族炭化水素類；グライム、ジグライム、トリグライム、ジオキサン、テトラヒドロフラン等のエーテル類等が例示される。これらのうちの一種を単独で又は二種以上を組み合わせてもよい。 Examples of the solvent used here include aliphatic hydrocarbons such as hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, heptane, and octane; aromatic hydrocarbons such as toluene, ethylbenzene, and xylene; glyme, diglyme, triglyme, dioxane, Examples include ethers such as tetrahydrofuran. One of these may be used alone or in combination of two or more.
　（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を用いて酸化アルミニウムを蒸着して酸化アルミニウム膜を形成するときの反応系内の圧力は、好ましくは１Ｐａ～２００ｋＰａ、より好ましくは１０Ｐａ～１１０ｋＰａである。 The pressure in the reaction system when forming an aluminum oxide film by vapor-depositing aluminum oxide using a (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is preferably 1 Pa to 200 kPa, more preferably 10 Pa to 110 kPa. .
　（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を用いて酸化アルミニウム膜を形成するときの成膜対象物の温度は、好ましくは２００～６００℃、より好ましくは３００～５００℃である。これによって、酸化アルミニウム膜の厚みのばらつきを一層低減することができる。また、酸化アルミニウム膜に含まれる不純物を十分に低減して、高品位な酸化アルミニウム膜を製造することができる。さらに、３００～５００℃であれば、成膜対象物上の温度に多少のばらつきがあったとしても膜厚が変化することを抑制できる。したがって、膜厚の均一性に優れる酸化アルミニウム膜を容易に製造することができる。 The temperature of the film formation target when forming an aluminum oxide film using (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is preferably 200 to 600 ° C., more preferably 300 to 500 ° C. Thereby, the variation in the thickness of the aluminum oxide film can be further reduced. In addition, a high-quality aluminum oxide film can be manufactured by sufficiently reducing impurities contained in the aluminum oxide film. Further, when the temperature is 300 to 500 ° C., it is possible to suppress the change in the film thickness even if there is some variation in the temperature on the film formation target. Therefore, an aluminum oxide film having excellent film thickness uniformity can be easily manufactured.
　（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を気化させるときの温度は、好ましくは３０～２５０℃、より好ましくは６０～２００℃である。酸化アルミニウム膜を形成する際、全供給ガス量［反応性ガス＋（ジターシャリーブチル（アルキル）アミジナト）ジアルキルアルミニウム化合物を含むガス］に対する酸素源（例えば、酸化性ガス、水蒸気又はアルコール蒸気、あるいはこれらの混合ガス）となる反応性ガスの含有割合は、好ましくは３～９９容量％、より好ましくは５～９８容量％である。 The temperature at which the (ditertiary butyl (alkyl) amidinato) dialkylaluminum compound is vaporized is preferably 30 to 250 ° C., more preferably 60 to 200 ° C. When forming an aluminum oxide film, an oxygen source (for example, oxidizing gas, water vapor or alcohol vapor, or these) with respect to the total supply gas amount [reactive gas + (gas containing ditertiary butyl (alkyl) amidinato) dialkylaluminum compound] The content ratio of the reactive gas to be a mixed gas is preferably 3 to 99% by volume, more preferably 5 to 98% by volume.
　本実施形態の酸化アルミニウム膜は、加熱されている成膜対象物上にアルミニウム化合物を供給し、当該アルミニウム化合物を酸化することにより成膜対象物上に形成される。酸化アルミニウム膜は、例えば、１～１００ｎｍ、好ましくは５～５０ｍｍの厚みを有する。 The aluminum oxide film of this embodiment is formed on a film formation target by supplying an aluminum compound onto the heated film formation target and oxidizing the aluminum compound. The aluminum oxide film has a thickness of, for example, 1 to 100 nm, preferably 5 to 50 mm.
　酸化アルミニウム膜は不純物濃度を十分に低減して良好な品質にすることができる。酸化アルミニウム膜における酸化アルミニウムの含有量は例えば９５質量％以上であり、好ましくは９８質量％以上であり、より好ましくは９９質量％以上である。このように純度が高く且つ厚みの小さい高品位の酸化アルミニウム膜は、半導体分野において有用である。酸化アルミニウム膜は酸化アルミニウムのみからなるものであってもよいし、酸化アルミニウムと炭化アルミニウムのみからなるものであってもよい。本明細書では、酸化アルミニウムの含有量が９０質量％以上のものを、「酸化アルミニウム膜」という。酸化アルミニウム膜の膜みのばらつきは、例えば１０ｎｍ未満である。なお、酸化アルミニウム膜の厚みのばらつきとは、任意に選択した箇所で測定される膜厚の差違（最大値－最小値）である。 The aluminum oxide film can have a satisfactory quality by sufficiently reducing the impurity concentration. The content of aluminum oxide in the aluminum oxide film is, for example, 95% by mass or more, preferably 98% by mass or more, and more preferably 99% by mass or more. Such a high-quality aluminum oxide film having a high purity and a small thickness is useful in the semiconductor field. The aluminum oxide film may be composed only of aluminum oxide, or may be composed only of aluminum oxide and aluminum carbide. In the present specification, an aluminum oxide content of 90% by mass or more is referred to as an “aluminum oxide film”. The variation in thickness of the aluminum oxide film is, for example, less than 10 nm. The variation in the thickness of the aluminum oxide film is a difference in film thickness (maximum value−minimum value) measured at an arbitrarily selected location.
　成膜対象物としては、無機酸化物を含む基板が挙げられる。このような基板の上に酸化アルミニウム膜を形成することによって、基板と基板の上に酸化アルミニウム膜を有する積層体を得ることができる。 The film formation target includes a substrate containing an inorganic oxide. By forming an aluminum oxide film on such a substrate, a stacked body having the aluminum oxide film on the substrate and the substrate can be obtained.
　以上、本発明の実施形態について説明したが、本発明は上記実施形態に何ら限定されるものではない。 As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment at all.
　実施例及び比較例を参照して本発明の内容をより詳細に説明するが、本発明は下記の実施例に限定されるものではない。 The content of the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.
［実施例１］［（ジターシャリーブチル（メチル）アミジナト）ジメチルアルミニウムの合成］
　攪拌装置、温度計及び滴下漏斗を備えた内容積５０ｍｌのフラスコに、トリメチルアルミニウム１．２６ｇ（１７．５ｍｍｏｌ）、及びヘキサン２０ｍＬを加えて冷却した。ここにジターシャリーブチルカルボジイミド２．７３ｇ（１７．５ｍｍｏｌ）を内温が０～６℃になるようにゆるやかに滴下した。滴下終了後、室温（２５℃）下において１５時間攪拌した。反応終了後、その反応液を濃縮し、濃縮物を減圧蒸留（オイルバスの温度：７０℃、フラスコ内の圧力：１３３．３Ｐａ）して、白色固体の（ジターシャリーブチル（メチル）アミジナト）ジメチルアルミニウム３．４４ｇ得た（単離収率：８７％）。 [Example 1] [Synthesis of (ditertiary butyl (methyl) amidinato) dimethylaluminum]
1.26 g (17.5 mmol) of trimethylaluminum and 20 mL of hexane were added to a flask having an internal volume of 50 ml equipped with a stirrer, a thermometer and a dropping funnel and cooled. Ditertiary butylcarbodiimide (2.73 g, 17.5 mmol) was slowly added dropwise thereto so that the internal temperature was 0 to 6 ° C. After completion of dropping, the mixture was stirred at room temperature (25 ° C.) for 15 hours. After completion of the reaction, the reaction solution was concentrated, and the concentrate was distilled under reduced pressure (oil bath temperature: 70 ° C., pressure in the flask: 133.3 Pa) to give (ditertiary butyl (methyl) amidinato) dimethyl as a white solid. 3.44 g of aluminum was obtained (isolation yield: 87%).
　（ジターシャリーブチル（メチル）アミジナト）ジメチルアルミニウムは、上記式（１）のＲがメチル基である化合物（上記式（２）の化合物）である。得られた（ジターシャリーブチル（メチル）アミジナト）ジメチルアルミニウムの物性値は以下のとおりであった。 (Ditertiary butyl (methyl) amidinato) dimethylaluminum is a compound in which R in the above formula (1) is a methyl group (a compound in the above formula (2)). The physical properties of the obtained (ditertiary butyl (methyl) amidinato) dimethylaluminum were as follows.
１Ｈ－ＮＭＲ（Ｃ６Ｄ６，δ（ｐｐｍ））；－０．１４（６Ｈ，ｓ），１．０５（１８Ｈ，ｓ），３．１４（３Ｈ，ｓ） 1 H-NMR (C 6 D 6 , δ (ppm)); -0.14 (6H, s), 1.05 (18H, s), 3.14 (3H, s)
［実施例２］［（ジターシャリーブチル（エチル）アミジナト）ジエチルアルミニウムの合成］
　攪拌装置、温度計及び滴下漏斗を備えた内容積５０ｍｌのフラスコに、トリエチルアルミニウム２．００ｇ（１７．５ｍｍｏｌ）、及びヘキサン２０ｍＬを加えて冷却した。ここにジターシャリーブチルカルボジイミド２．７３ｇ（１７．５ｍｍｏｌ）を内温が０～６℃になるようにゆるやかに滴下した。滴下終了後、室温下において１５時間攪拌した。反応終了後、その反応液を濃縮し、濃縮物を減圧蒸留（オイルバス温度：８０℃、フラスコ内の圧力：１３３．３Ｐａ）して、無色透明液体の（ジターシャリーブチル（エチル）アミジナト）ジエチルアルミニウム４．４３ｇ得た（単離収率：９４％）。 [Example 2] [Synthesis of (ditertiary butyl (ethyl) amidinato) diethylaluminum]
To a 50-ml flask equipped with a stirrer, thermometer and dropping funnel, 2.00 g (17.5 mmol) of triethylaluminum and 20 mL of hexane were added and cooled. Ditertiary butylcarbodiimide (2.73 g, 17.5 mmol) was slowly added dropwise thereto so that the internal temperature was 0 to 6 ° C. After completion of dropping, the mixture was stirred at room temperature for 15 hours. After completion of the reaction, the reaction solution was concentrated, and the concentrate was distilled under reduced pressure (oil bath temperature: 80 ° C., pressure in the flask: 133.3 Pa) to give a colorless transparent liquid (ditertiary butyl (ethyl) amidinato) diethyl. 4.43 g of aluminum was obtained (isolation yield: 94%).
　（ジターシャリーブチル（エチル）アミジナト）ジエチルアルミニウムは、上記式（１）のＲがエチル基である化合物（上記式（３）の化合物）である。得られた（ジターシャリーブチル（エチル）アミジナト）ジエチルアルミニウムの物性値は以下のとおりであった。 (Ditertiary butyl (ethyl) amidinato) diethylaluminum is a compound in which R in the above formula (1) is an ethyl group (compound of the above formula (3)). The physical properties of the obtained (ditertiary butyl (ethyl) amidinato) diethylaluminum were as follows.
１Ｈ－ＮＭＲ（Ｃ６Ｄ６，δ（ｐｐｍ））；０．３５（４Ｈ，ｑ），０．９８（３Ｈ，ｔ），１．１４（１８Ｈ，ｓ），１．４０（６Ｈ，ｔ），２．１４（２Ｈ，ｑ） 1 H-NMR (C 6 D 6 , δ (ppm)); 0.35 (4H, q), 0.98 (3H, t), 1.14 (18H, s), 1.40 (6H, t ), 2.14 (2H, q)
［実施例３］［ジターシャリーブチル（メチル）アミジナト）ジエチルアルミニウムの合成］
　攪拌装置、温度計及び滴下漏斗を備えた内容積１００ｍｌのフラスコに、メチルリチウムのエーテル溶液（１．０８Ｍ, ２９．７ｍｍｏｌ）を加えて冷却した。ここにジターシャリーブチルカルボジイミド４．５０ｇ（２９．２ｍｍｏｌ）を内温が０～６℃になるようにゆるやかに滴下した。滴下終了後、室温下において１時間攪拌した。次に、その反応液にジエチルアルミニウムクロライド３．５０ｇ（２９．０ｍｍｏｌ）を内温が０～６℃になるようにゆるやかに滴下した。滴下終了後、室温下において１５時間攪拌した。反応終了後、得られた反応液をセライト濾過して得られた濾液を濃縮し、濃縮物を得た。この濃縮物の減圧蒸留（オイルバス温度：７０℃、フラスコ内の圧力：１３３．３Ｐａ）を行って、無色透明液体の（ジターシャリーブチル（メチル）アミジナト）ジエチルアルミニウム６．２９ｇ得た（単離収率：８５％）。 [Example 3] [Synthesis of ditertiary butyl (methyl) amidinato) diethylaluminum]
An ether solution of methyllithium (1.08M, 29.7 mmol) was added to a flask having an internal volume of 100 ml equipped with a stirrer, a thermometer and a dropping funnel and cooled. Ditertiary butylcarbodiimide (4.50 g, 29.2 mmol) was slowly added dropwise thereto so that the internal temperature was 0 to 6 ° C. After completion of dropping, the mixture was stirred at room temperature for 1 hour. Next, 3.50 g (29.0 mmol) of diethylaluminum chloride was slowly added dropwise to the reaction solution so that the internal temperature was 0 to 6 ° C. After completion of dropping, the mixture was stirred at room temperature for 15 hours. After completion of the reaction, the resulting reaction solution was filtered through Celite, and the filtrate obtained was concentrated to obtain a concentrate. The concentrate was distilled under reduced pressure (oil bath temperature: 70 ° C., pressure in the flask: 133.3 Pa) to obtain 6.29 g of a colorless transparent liquid (ditertiary butyl (methyl) amidinato) diethylaluminum (isolation) Yield: 85%).
　（ジターシャリーブチル（メチル）アミジナト）ジエチルアルミニウムは、上記式（５）の化合物に相当する。得られた（ジターシャリーブチル（メチル）アミジナト）ジエチルアルミニウムの物性値は以下のとおりであった。 (Ditertiary butyl (methyl) amidinato) diethylaluminum corresponds to the compound of the above formula (5). The physical properties of the obtained (ditertiary butyl (methyl) amidinato) diethylaluminum were as follows.
　１Ｈ－ＮＭＲ（Ｃ６Ｄ６，δ（ｐｐｍ））；０．３５（４Ｈ，ｑ），１．１０（１８Ｈ，ｓ），１．４１（６Ｈ，ｔ），１．７０（３Ｈ，ｓ） 1 H-NMR (C 6 D 6 , δ (ppm)); 0.35 (4H, q), 1.10 (18H, s), 1.41 (6H, t), 1.70 (3H, s) )
［実施例４］［（ジターシャリーブチル（エチル）アミジナト）ジメチルアルミニウムの合成］
　攪拌装置、温度計及び滴下漏斗を備えた内容積１００ｍｌのフラスコに、エチルリチウムのベンゼン／シクロヘキサン溶液(０．５０Ｍ，３０．０ｍｍｏｌ)を加えて冷却した。ここにジターシャリーブチルカルボジイミド４．６３ｇ（３０．０ｍｍｏｌ）を内温が０～６℃になるようにゆるやかに滴下した。滴下終了後、室温下において１時間攪拌した。次に、その反応液にジメチルアルミニウムクロライド２．８３ｇ（３０．６ｍｍｏｌ）を内温が０～６℃になるようにゆるやかに滴下した。滴下終了後、室温下において１５時間攪拌した。反応終了後、得られた反応液をセライト濾過して得られた濾液を濃縮し、濃縮物を得た。この濃縮物の減圧蒸留（オイルバス温度６０℃、１３３．３Ｐａ）を行って、無色透明液体の（ジターシャリーブチル（エチル）アミジナト）ジメチルアルミニウム５．４０ｇ得た（単離収率：７５％）。 Example 4 [Synthesis of (ditertiary butyl (ethyl) amidinato) dimethylaluminum]
A benzene / cyclohexane solution of ethyllithium (0.50 M, 30.0 mmol) was added to a flask having an internal volume of 100 ml equipped with a stirrer, a thermometer and a dropping funnel and cooled. Ditertiary butylcarbodiimide (4.63 g, 30.0 mmol) was slowly added dropwise thereto so that the internal temperature became 0 to 6 ° C. After completion of dropping, the mixture was stirred at room temperature for 1 hour. Next, 2.83 g (30.6 mmol) of dimethylaluminum chloride was slowly added dropwise to the reaction solution so that the internal temperature was 0 to 6 ° C. After completion of dropping, the mixture was stirred at room temperature for 15 hours. After completion of the reaction, the resulting reaction solution was filtered through Celite, and the filtrate obtained was concentrated to obtain a concentrate. This concentrate was distilled under reduced pressure (oil bath temperature 60 ° C., 133.3 Pa) to obtain 5.40 g of (ditertiary butyl (ethyl) amidinato) dimethylaluminum as a colorless transparent liquid (isolation yield: 75%). .
　（ジターシャリーブチル（エチル）アミジナト）ジメチルアルミニウムは上記式（４）の化合物である。得られた（ジターシャリーブチル（エチル）アミジナト）ジメチルアルミニウムの物性値は以下のとおりであった。 (Ditertiary butyl (ethyl) amidinato) dimethylaluminum is a compound of the above formula (4). The physical properties of the obtained (ditertiary butyl (ethyl) amidinato) dimethylaluminum were as follows.
　１Ｈ－ＮＭＲ（Ｃ６Ｄ６，δ（ｐｐｍ））；－０．２３（６Ｈ，ｓ），０．９５（３Ｈ，ｔ），１．１４（１８Ｈ，ｓ），２．１３（２Ｈ，ｑ） 1 H-NMR (C 6 D 6 , δ (ppm)); −0.23 (6H, s), 0.95 (3H, t), 1.14 (18H, s), 2.13 (2H, q)
［実施例５］［酸化アルミニウム膜の製造］
　アルミニウム化合物として、実施例２において合成した（ジターシャリーブチル（エチル）アミジナト）ジエチルアルミニウム、すなわち上記式（３）で表される化合物を用いて、ＡＬＤ法により基板上に酸化アルミニウム膜を成膜した。酸化アルミニウム膜の成膜は、図１に示す装置を用いて行った。 [Example 5] [Production of aluminum oxide film]
An aluminum oxide film was formed on the substrate by the ALD method using (ditertiary butyl (ethyl) amidinato) diethylaluminum synthesized in Example 2 as the aluminum compound, that is, the compound represented by the above formula (3). . The aluminum oxide film was formed using the apparatus shown in FIG.
　図１に示す装置は、アルミニウム化合物２を気化する気化器１（ＳＵＳ製アンプル）と、水７を気化して反応性ガスである水蒸気を供給する気化器６（ＳＵＳ製アンプル）と、基板１５及び当該基板１５を加熱するヒータ１４を有し、アルミニウム化合物２と水蒸気とを反応させて基板１５上に酸化アルミニウム膜を形成する反応器１１と、を備える。反応器１１には流路を介して真空ポンプが接続されている。当該流路には圧力計１３、圧力調節バルブ１２及びトラップ１６が設けられている。これによって、反応器１１内の圧力は所定の範囲に調節される。反応器１１から導出されたガスは、トラップ１６及び真空ポンプを経て、大気中に排気される。 The apparatus shown in FIG. 1 includes a vaporizer 1 (SUS ampule) that vaporizes an aluminum compound 2, a vaporizer 6 (SUS ampule) that vaporizes water 7 and supplies water vapor as a reactive gas, and a substrate 15. And a reactor 11 having a heater 14 for heating the substrate 15 and reacting the aluminum compound 2 with water vapor to form an aluminum oxide film on the substrate 15. A vacuum pump is connected to the reactor 11 via a flow path. A pressure gauge 13, a pressure control valve 12 and a trap 16 are provided in the flow path. Thereby, the pressure in the reactor 11 is adjusted to a predetermined range. The gas led out from the reactor 11 is exhausted to the atmosphere through the trap 16 and the vacuum pump.
　ヒータ３及び恒温槽８をそれぞれ備える気化器１及び気化器６に、上記実施例２で合成されたアルミニウム化合物２及び水７をそれぞれ収容した。気化器１には、マスフローコントローラ４によって流量調節され、予熱器５によって予熱されたアルゴンガスを供給した。これによって、気化器１から、アルミニウム化合物２を含むアルゴンガスが、反応器１１に導入された。 The aluminum compound 2 and the water 7 synthesized in Example 2 were accommodated in the vaporizer 1 and the vaporizer 6 respectively including the heater 3 and the constant temperature bath 8. The vaporizer 1 was supplied with argon gas whose flow rate was adjusted by the mass flow controller 4 and preheated by the preheater 5. As a result, argon gas containing the aluminum compound 2 was introduced into the reactor 11 from the vaporizer 1.
　一方、気化器６から、恒温槽８によって一定温度に調整されて気化された水蒸気が、反応器１１に導入された。気化器１からのアルミニウム化合物２を含むアルゴンガスと、気化器６からの水蒸気は、交互に反応器１１に導入された。アルミニウム化合物２を含むアルゴンガス及び水蒸気の導入量は、バルブ１７及びバルブ１８によってそれぞれ調節した。アルミニウム化合物２を含むアルゴンガス及び水蒸気は、それぞれ、マスフローコントローラ９によって流量調節され、予熱器１０によって予熱された希釈用のアルゴンガスに同伴されて反応器１１に導入された。 On the other hand, water vapor that was vaporized by being adjusted to a constant temperature by the thermostatic chamber 8 was introduced into the reactor 11 from the vaporizer 6. The argon gas containing the aluminum compound 2 from the vaporizer 1 and the water vapor from the vaporizer 6 were alternately introduced into the reactor 11. The introduction amounts of argon gas and water vapor containing the aluminum compound 2 were adjusted by a valve 17 and a valve 18, respectively. The argon gas and water vapor containing the aluminum compound 2 were each adjusted in flow rate by the mass flow controller 9 and introduced into the reactor 11 along with the dilution argon gas preheated by the preheater 10.
　アルミニウム化合物２及び水７を反応器１１に交互に供給して、ヒータ１４で所定の温度に加熱された基板１５の上に酸化アルミニウム膜２０を形成した。図１の装置の運転条件は、以下のとおりとした。 Aluminum compound 2 and water 7 were alternately supplied to the reactor 11 to form an aluminum oxide film 20 on the substrate 15 heated to a predetermined temperature by the heater 14. The operating conditions of the apparatus of FIG. 1 were as follows.
　アルミニウム化合物２の気化温度（気化器１）：９０℃
　Ａｒガス（キャリアーガス）流量：５ｍＬ／ｍｉｎ（マスフローコントローラ４で調整）
　アルミニウム化合物２の供給時間：１秒間
　アルミニウム化合物２のパージ時間：５秒間
　水７の気化温度：１０℃
　水７の供給時間：１秒間
　水７のパージ時間：５秒間
　希釈用のＡｒガス流量：５０ｍＬ／ｍｉｎ．
　基板１５の材質：ＳｉＯ２／Ｓｉ
　基板１５のサイズ：縦×横＝２０ｍｍ×２０ｍｍ
　基板１５の温度：３００℃
　反応器１１内の圧力：１３３３Ｐａ
　サイクル回数：５００回（アルミニウム化合物２を含むアルゴンガスの導入と、気化器６からの水蒸気の導入を５００回繰り返した。） The vaporization temperature of the aluminum compound 2 (vaporizer 1): 90 ° C
Ar gas (carrier gas) flow rate: 5 mL / min (adjusted with mass flow controller 4)
Aluminum compound 2 supply time: 1 second Aluminum compound 2 purge time: 5 seconds Water 7 vaporization temperature: 10 ° C.
Water 7 supply time: 1 second Water 7 purge time: 5 seconds Ar gas flow rate for dilution: 50 mL / min.
Material of substrate 15: SiO 2 / Si
Size of substrate 15: vertical x horizontal = 20 mm x 20 mm
The temperature of the substrate 15: 300 ° C.
Pressure in the reactor 11: 1333 Pa
Number of cycles: 500 times (introduction of argon gas containing aluminum compound 2 and introduction of water vapor from the vaporizer 6 were repeated 500 times)
　上述の条件で基板１５上に酸化アルミニウム膜２０を形成した。形成した酸化アルミニウム膜２０の厚みを、反射分光膜厚計を用いて測定した。また、ＸＰＳ（Ｘ線光電子分光）測定装置を用いて酸化アルミニウム膜２０の組成を分析した。厚み及び組成分析の結果は、表１に示すとおりであった。 The aluminum oxide film 20 was formed on the substrate 15 under the above conditions. The thickness of the formed aluminum oxide film 20 was measured using a reflection spectral film thickness meter. Further, the composition of the aluminum oxide film 20 was analyzed using an XPS (X-ray photoelectron spectroscopy) measuring apparatus. The results of thickness and composition analysis were as shown in Table 1.
　酸化アルミニウム膜２０の厚みは、任意に選択した５箇所について行い、最大値と最小値を求めた。最大値－最小値＜１０ｎｍであった場合には、その算術平均値を表に示した。一方、最大値－最小値≧１０ｎｍであった場合には、最大値と最小値を示した。 The thickness of the aluminum oxide film 20 was performed at five arbitrarily selected locations, and the maximum value and the minimum value were obtained. When the maximum value−the minimum value <10 nm, the arithmetic average value is shown in the table. On the other hand, when the maximum value−minimum value ≧ 10 nm, the maximum value and the minimum value were shown.
［実施例６～１０］［酸化アルミニウム膜の製造］
　基板１５の温度を表１に示すとおりに変更したこと以外は、実施例５と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表１に示すとおりであった。 [Examples 6 to 10] [Production of aluminum oxide film]
An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that the temperature of the substrate 15 was changed as shown in Table 1. The analysis results of the thickness and composition of the formed aluminum oxide film 20 were as shown in Table 1.
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
　実施例５～１０の酸化アルミニウム膜は、いずれも、厚みのばらつきがなく、厚みの均一性に優れていた。また、基板１５の温度が３００～５００℃の範囲内であれば、酸化アルミニウム膜の厚みはあまり変化しないことが確認された。このことから、実施例２において合成した（ジターシャリーブチル（エチル）アミジナト）ジエチルアルミニウムを用いることによって、酸化アルミニウム膜を安定して形成できることが確認された。実施例１０の酸化アルミニウム膜における酸化アルミニウムの含有量は９５質量%以上であり、炭化アルミニウムの含有量は５質量％以下であった。 The aluminum oxide films of Examples 5 to 10 had no thickness variation and excellent thickness uniformity. Further, it was confirmed that when the temperature of the substrate 15 is in the range of 300 to 500 ° C., the thickness of the aluminum oxide film does not change much. From this, it was confirmed that the aluminum oxide film can be formed stably by using (ditertiary butyl (ethyl) amidinato) diethylaluminum synthesized in Example 2. The aluminum oxide content in the aluminum oxide film of Example 10 was 95% by mass or more, and the aluminum carbide content was 5% by mass or less.
［実施例１１］［酸化アルミニウム膜の製造］
　アルミニウム化合物として、実施例３において合成した（ジターシャリーブチル（メチル）アミジナト）ジエチルアルミニウム、すなわち上記式（５）で表される化合物を用いた。このアルミニウム化合物を用いたこと、及び、気化器１におけるアルミニウム化合物の気化温度を８０℃にしたこと以外は、実施例５と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表２に示すとおりであった。 [Example 11] [Production of aluminum oxide film]
As the aluminum compound, (ditertiary butyl (methyl) amidinato) diethylaluminum synthesized in Example 3, that is, the compound represented by the above formula (5) was used. An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that this aluminum compound was used and the vaporization temperature of the aluminum compound in the vaporizer 1 was set to 80 ° C. The analysis results of the thickness and composition of the formed aluminum oxide film 20 were as shown in Table 2.
［実施例１２～１６］［酸化アルミニウム膜の製造］
　基板１５の温度を表２に示すとおりに変更したこと以外は、実施例１１と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表２に示すとおりであった。 [Examples 12 to 16] [Production of aluminum oxide film]
An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 11 except that the temperature of the substrate 15 was changed as shown in Table 2. The analysis results of the thickness and composition of the formed aluminum oxide film 20 were as shown in Table 2.
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000015
　実施例１１～１６の酸化アルミニウム膜は、いずれも、厚みのばらつきがなく、厚みの均一性に優れていた。また、基板１５の温度が３００～５００℃の範囲内であれば、酸化アルミニウム膜の厚みはあまり変化しないことが確認された。このことから、実施例３において合成した（ジターシャリーブチル（メチル）アミジナト）ジエチルアルミニウムを用いることによって、酸化アルミニウム膜を安定して形成できることが確認された。 The aluminum oxide films of Examples 11 to 16 had no thickness variation and were excellent in thickness uniformity. Further, it was confirmed that when the temperature of the substrate 15 is in the range of 300 to 500 ° C., the thickness of the aluminum oxide film does not change much. From this, it was confirmed that by using (ditertiary butyl (methyl) amidinato) diethylaluminum synthesized in Example 3, an aluminum oxide film can be formed stably.
［実施例１７］［酸化アルミニウム膜の製造］
　アルミニウム化合物として、実施例４において合成した（ジターシャリーブチル（エチル）アミジナト）ジメチルアルミニウム、すなわち式（４）で表される化合物を用いた。このアルミニウム化合物を用いたこと、及び、気化器１におけるアルミニウム化合物の気化温度を７０℃にしたこと以外は、実施例５と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表３に示すとおりであった。 [Example 17] [Production of aluminum oxide film]
As the aluminum compound, (ditertiary butyl (ethyl) amidinato) dimethylaluminum synthesized in Example 4, that is, the compound represented by the formula (4) was used. An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that this aluminum compound was used and the vaporization temperature of the aluminum compound in the vaporizer 1 was set to 70 ° C. The analysis results of the thickness and composition of the formed aluminum oxide film 20 are as shown in Table 3.
［実施例１８～２０］［酸化アルミニウム膜の製造］
　基板１５の温度を表３に示すとおりに変更したこと以外は、実施例１７と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表３に示すとおりであった。 [Examples 18 to 20] [Production of aluminum oxide film]
An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 17 except that the temperature of the substrate 15 was changed as shown in Table 3. The analysis results of the thickness and composition of the formed aluminum oxide film 20 are as shown in Table 3.
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000016
　実施例１７～２０の酸化アルミニウム膜は、いずれも、厚みのばらつきがなく、厚みの均一性に優れていた。また、基板１５の温度が３００～５００℃の範囲内において、酸化アルミニウム膜の厚みは変化しないことが確認された。このことから、実施例４において合成した（ジターシャリーブチル（エチル）アミジナト）ジメチルアルミニウムを用いることによって、酸化アルミニウム膜を安定して形成できることが確認された。 The aluminum oxide films of Examples 17 to 20 had no thickness variation and excellent thickness uniformity. Further, it was confirmed that the thickness of the aluminum oxide film did not change when the temperature of the substrate 15 was in the range of 300 to 500 ° C. From this, it was confirmed that the aluminum oxide film can be stably formed by using (ditertiary butyl (ethyl) amidinato) dimethylaluminum synthesized in Example 4.
［実施例２１］［酸化アルミニウム膜の製造］
　アルミニウム化合物として、実施例１において合成した（ジターシャリーブチル（メチル）アミジナト）ジメチルアルミニウム、すなわち式（２）で表される化合物を用いた。このアルミニウム化合物を用いたこと、及び、気化器１におけるアルミニウム化合物の気化温度を７０℃にしたこと以外は、実施例５と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表４に示すとおりであった。 [Example 21] [Production of aluminum oxide film]
As the aluminum compound, (ditertiary butyl (methyl) amidinato) dimethylaluminum synthesized in Example 1, that is, the compound represented by the formula (2) was used. An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that this aluminum compound was used and the vaporization temperature of the aluminum compound in the vaporizer 1 was set to 70 ° C. The analysis results of the thickness and composition of the formed aluminum oxide film 20 are as shown in Table 4.
［実施例２２～２４］［酸化アルミニウム膜の製造］
　基板１５の温度を表４に示すとおりに変更したこと以外は、実施例２１と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表４に示すとおりであった。 [Examples 22 to 24] [Production of aluminum oxide film]
An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 21 except that the temperature of the substrate 15 was changed as shown in Table 4. The analysis results of the thickness and composition of the formed aluminum oxide film 20 are as shown in Table 4.
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000017
　実施例２１～２４の酸化アルミニウム膜は、いずれも、厚みのばらつきがなく、厚みの均一性に優れていた。また、基板１５の温度が３００～５００℃の範囲内において、酸化アルミニウム膜の厚みは変化しないことが確認された。このことから、実施例１において合成したジターシャリーブチル（メチル）アミジナト）ジメチルアルミニウムを用いることによって、酸化アルミニウム膜を安定して形成できることが確認された。 The aluminum oxide films of Examples 21 to 24 had no thickness variation and were excellent in thickness uniformity. Further, it was confirmed that the thickness of the aluminum oxide film did not change when the temperature of the substrate 15 was in the range of 300 to 500 ° C. From this, it was confirmed that the aluminum oxide film can be stably formed by using the ditertiary butyl (methyl) amidinato) dimethylaluminum synthesized in Example 1.
［比較例１］［（ジイソプロピル（メチル）アミジナト）ジメチルアルミニウムの合成］
　攪拌装置、温度計及び滴下漏斗を備えた内容積５０ｍｌのフラスコに、トリメチルアルミニウム２．００ｇ（２７．７ｍｍｏｌ）、及びヘキサン２５ｍＬを加えて冷却した。ここにジイソプロピルカルボジイミド３．５０ｇ（２７．７ｍｍｏｌ）を内温が０～６℃になるようにゆるやかに滴下した。滴下終了後、室温下において１５時間攪拌した。反応終了後、その反応液を濃縮し、濃縮物を減圧蒸留（オイルバス温度７０℃、フラスコ内の圧力：１３３．３Ｐａ）して、透明液体の（ジイソプロピル（メチル）アミジナト）ジメチルアルミニウム４．９４ｇ得た（単離収率：９０質量％）。 [Comparative Example 1] [Synthesis of (Diisopropyl (methyl) amidinato) dimethylaluminum]
To a flask having an internal volume of 50 ml equipped with a stirrer, a thermometer and a dropping funnel, 2.00 g (27.7 mmol) of trimethylaluminum and 25 mL of hexane were added and cooled. Diisopropylcarbodiimide (3.50 g, 27.7 mmol) was slowly added dropwise thereto so that the internal temperature became 0 to 6 ° C. After completion of dropping, the mixture was stirred at room temperature for 15 hours. After completion of the reaction, the reaction solution was concentrated, and the concentrate was distilled under reduced pressure (oil bath temperature 70 ° C., pressure in the flask: 133.3 Pa) to obtain 4.94 g of a transparent liquid (diisopropyl (methyl) amidinato) dimethylaluminum. Obtained (isolation yield: 90% by mass).
　（ジイソプロピル（メチル）アミジナト）ジメチルアルミニウムは、下記の化学式で表される。得られた（ジイソプロピル（メチル）アミジナト）ジメチルアルミニウムの物性値は以下のとおりであった。 (Diisopropyl (methyl) amidinato) dimethylaluminum is represented by the following chemical formula. The physical properties of the obtained (diisopropyl (methyl) amidinato) dimethylaluminum were as follows.
Figure JPOXMLDOC01-appb-C000018
Figure JPOXMLDOC01-appb-C000018
　１Ｈ－ＮＭＲ（Ｃ６Ｄ６，δ（ｐｐｍ））；－０．２３（６Ｈ，ｓ），０．９６（１２Ｈ，ｄ）１．２６（３Ｈ，ｔ），３．０９－３．１５（２Ｈ，ｍ） 1 H-NMR (C 6 D 6 , δ (ppm)); −0.23 (6H, s), 0.96 (12H, d) 1.26 (3H, t), 3.09-3.15 (2H, m)
［比較例２］［酸化アルミニウム膜の製造］
　アルミニウム化合物として、比較例１において合成した（ジイソプロピル（メチル）アミジナト）ジメチルアルミニウムを用いた。このアルミニウム化合物を用いたこと、及び、気化器１におけるアルミニウム化合物の気化温度を５０℃にしたこと以外は、実施例５と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表５に示すとおりであった。 [Comparative Example 2] [Production of aluminum oxide film]
As the aluminum compound, (diisopropyl (methyl) amidinato) dimethylaluminum synthesized in Comparative Example 1 was used. An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that this aluminum compound was used and the vaporization temperature of the aluminum compound in the vaporizer 1 was set to 50 ° C. The analysis results of the thickness and composition of the formed aluminum oxide film 20 were as shown in Table 5.
［比較例３］［酸化アルミニウム膜の製造］
　基板１５の温度を表５に示すとおりに変更したこと以外は、比較例２と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表５に示すとおりであった。 [Comparative Example 3] [Production of aluminum oxide film]
An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Comparative Example 2 except that the temperature of the substrate 15 was changed as shown in Table 5. The analysis results of the thickness and composition of the formed aluminum oxide film 20 were as shown in Table 5.
Figure JPOXMLDOC01-appb-T000019
Figure JPOXMLDOC01-appb-T000019
　比較例２，３の酸化アルミニウム膜は、どちらも厚みのばらつきが大きく、各実施例よりも厚みの均一性が劣っていた。このように厚みのばらつきが大きい原因としては、アルミニウム化合物の熱安定性が低いため、熱分解が不均一に進行し、成膜速度のばらつきが大きくなっていることが考えられる。 The aluminum oxide films of Comparative Examples 2 and 3 both had large variations in thickness, and the thickness uniformity was inferior to those of the Examples. It can be considered that the reason why the variation in thickness is large is that the thermal stability of the aluminum compound is low, so that the thermal decomposition proceeds non-uniformly and the variation in the film forming rate is large.
［比較例４］［（ジメチルアミド）ジエチルアルミニウムの合成］
　攪拌装置、温度計及び滴下漏斗を備えた内容積５０ｍｌのフラスコに、ジメチルアミドリチウム１．３６ｇ（２６．７ｍｍｏｌ）、及びペンタン２５ｍＬを加えて冷却した。ここにジエチルアルミニウムクロライド３．２０ｇ（２６．５ｍｍｏｌ）を内温が０～６℃になるようにゆるやかに滴下した。滴下終了後、室温下において１５時間攪拌した。反応終了後、得られた白色懸濁液を濾過し、その濾液を濃縮した。得られた濃縮物を減圧蒸留（オイルバス温度９０℃、フラスコ内の圧力：１３３．３Ｐａ）して、透明液体として（ジメチルアミド）ジエチルアルミニウム３．０２ｇ得た（単離収率：８２質量％）。 [Comparative Example 4] [Synthesis of (dimethylamido) diethylaluminum]
1.36 g (26.7 mmol) of dimethylamidolithium and 25 mL of pentane were added to a flask having an internal volume of 50 ml equipped with a stirrer, a thermometer and a dropping funnel, and cooled. To this, 3.20 g (26.5 mmol) of diethylaluminum chloride was slowly added dropwise so that the internal temperature was 0 to 6 ° C. After completion of dropping, the mixture was stirred at room temperature for 15 hours. After completion of the reaction, the resulting white suspension was filtered and the filtrate was concentrated. The obtained concentrate was distilled under reduced pressure (oil bath temperature 90 ° C., pressure in the flask: 133.3 Pa) to obtain 3.02 g of (dimethylamido) diethylaluminum as a transparent liquid (isolated yield: 82% by mass). ).
　得られた（ジメチルアミド）ジエチルアルミニウムの物性値は以下のとおりであった。 The physical properties of the obtained (dimethylamide) diethylaluminum were as follows.
１Ｈ－ＮＭＲ（Ｃ６Ｄ６，δ（ｐｐｍ））；０．１０（４Ｈ，ｑ），１．２７（６Ｈ，ｔ）２．１０（６Ｈ，ｓ） 1 H-NMR (C 6 D 6 , δ (ppm)); 0.10 (4H, q), 1.27 (6H, t) 2.10 (6H, s)
［比較例５］［酸化アルミニウム膜の製造］
　アルミニウム化合物として、比較例４において合成した（ジメチルアミド）ジエチルアルミニウムを用いた。このアルミニウム化合物を用いたこと、及び、気化器１におけるアルミニウム化合物の気化温度を７０℃にしたこと以外は、実施例５と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表６に示すとおりであった。 [Comparative Example 5] [Production of aluminum oxide film]
As the aluminum compound, (dimethylamido) diethylaluminum synthesized in Comparative Example 4 was used. An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Example 5 except that this aluminum compound was used and the vaporization temperature of the aluminum compound in the vaporizer 1 was set to 70 ° C. Table 6 shows the analysis results of the thickness and composition of the formed aluminum oxide film 20.
［比較例６，７］［酸化アルミニウム膜の製造］
　基板１５の温度を表６に示すとおりに変更したこと以外は、比較例５と同様にして基板１５上に酸化アルミニウム膜２０を形成した。形成された酸化アルミニウム膜２０の厚み及び組成の分析結果は、表６に示すとおりであった。 [Comparative Examples 6 and 7] [Production of aluminum oxide film]
An aluminum oxide film 20 was formed on the substrate 15 in the same manner as in Comparative Example 5 except that the temperature of the substrate 15 was changed as shown in Table 6. Table 6 shows the analysis results of the thickness and composition of the formed aluminum oxide film 20.
Figure JPOXMLDOC01-appb-T000020
Figure JPOXMLDOC01-appb-T000020
　比較例５の酸化アルミニウム膜は、厚みのばらつきが小さかった。しかしながら、比較例６，７の酸化アルミニウム膜は、どちらも、厚みのばらつきが大きく、各実施例よりも厚みの均一性が劣っていた。このように厚みのばらつきが大きい原因としては、アルミニウム化合物の熱安定性が低いため、熱分解が不均一に進行し、成膜速度のばらつきが大きくなっていることが考えられる。表６に示す結果から、比較例４のアルミニウム化合物では、基板の温度が変動した場合に酸化アルミニウム膜の厚さのばらつきが大きくなることが確認された。このため、厚みのばらつきが低減された酸化アルミニウム膜を安定的に製造することができない。 The thickness variation of the aluminum oxide film of Comparative Example 5 was small. However, the aluminum oxide films of Comparative Examples 6 and 7 both had a large variation in thickness, and the thickness uniformity was inferior to those of the Examples. It can be considered that the reason why the variation in thickness is large is that the thermal stability of the aluminum compound is low, so that the thermal decomposition proceeds non-uniformly and the variation in the film forming rate is large. From the results shown in Table 6, it was confirmed that in the aluminum compound of Comparative Example 4, the variation in the thickness of the aluminum oxide film increases when the temperature of the substrate fluctuates. For this reason, it is not possible to stably produce an aluminum oxide film with reduced thickness variation.
　上述の各実施例において用いられた上記式（２）～（５）で表されるアルミニウム化合物は、安全性にも十分に優れていた。また、上述の条件で、アルミニウム薄膜を形成したことから、式（２）～（５）で表されるアルミニウム化合物は、反応性ガスとの反応性が良好であった。上記式（２）～（５）で表されるアルミニウム化合物を含有する蒸気は、基板表面への吸着性に優れることも分かった。さらに、基板の温度を３００～５００℃とすることによって、厚みの変化を低減しつつ、酸化アルミニウムの純度が高い酸化アルミニウム膜を形成することができる。すなわち、品質の良い酸化アルミニウム膜を製造することができる。 The aluminum compounds represented by the above formulas (2) to (5) used in the above examples were sufficiently excellent in safety. Further, since the aluminum thin film was formed under the above conditions, the aluminum compounds represented by the formulas (2) to (5) had good reactivity with the reactive gas. It has also been found that the vapor containing the aluminum compound represented by the above formulas (2) to (5) has excellent adsorptivity to the substrate surface. Furthermore, by setting the temperature of the substrate to 300 to 500 ° C., an aluminum oxide film with high aluminum oxide purity can be formed while reducing the change in thickness. That is, a high quality aluminum oxide film can be manufactured.
　厚みのばらつきが低減された酸化アルミニウム膜を安定的に製造し得る酸化アルミニウム膜の製造方法が提供される。当該製造方法に好適に用いられる製造原料、及びアルミニウム化合物が提供される。 Provided is a method for producing an aluminum oxide film capable of stably producing an aluminum oxide film with reduced thickness variation. Production raw materials and aluminum compounds that are suitably used in the production method are provided.
　１，６…気化器、２…アルミニウム化合物、３，１４…ヒータ、４，９…マスフローコントローラ、５，１０…予熱器、８…恒温槽、１１…反応器、１２…圧力調節バルブ、１３…圧力計、１５…基板、１６…トラップ、１７，１８…バルブ，２０…酸化アルミニウム膜。 DESCRIPTION OF SYMBOLS 1,6 ... Vaporizer, 2 ... Aluminum compound, 3,14 ... Heater, 4,9 ... Mass flow controller, 5,10 ... Preheater, 8 ... Constant temperature bath, 11 ... Reactor, 12 ... Pressure control valve, 13 ... Pressure gauge, 15 ... substrate, 16 ... trap, 17, 18 ... valve, 20 ... aluminum oxide film.

Claims (7)

  1. 　加熱されている成膜対象物上に下記式（１）で示されるアルミニウム化合物を供給し、前記アルミニウム化合物を酸化することにより前記成膜対象物上に酸化アルミニウム膜を形成する工程を有する、酸化アルミニウム膜の製造方法。
    Figure JPOXMLDOC01-appb-C000001
     　（式中、Ｒは炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲは互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。）     An oxidation process comprising supplying an aluminum compound represented by the following formula (1) onto a heated film formation target and oxidizing the aluminum compound to form an aluminum oxide film on the film formation target. A method for producing an aluminum film.
    Figure JPOXMLDOC01-appb-C000001
     (Wherein R represents a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R may be the same or different from each other. T-Bu represents a tertiary butyl group.)
  2. 　前記成膜対象物は３００～５００℃に加熱されている、請求項１に記載の酸化アルミニウム膜の製造方法。 The method for producing an aluminum oxide film according to claim 1, wherein the object to be formed is heated to 300 to 500 ° C.
  3. 　前記アルミニウム化合物は、下記式（１－１）で示される化合物を含む、請求項１又は２に記載の酸化アルミニウム膜の製造方法。
    Figure JPOXMLDOC01-appb-C000002
     　（式中、Ｒ１及びＲ２は互いに異なるアルキル基を示す。Ｒ１及びＲ２は、それぞれ独立に炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲ１は互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。）     The method for producing an aluminum oxide film according to claim 1 or 2, wherein the aluminum compound includes a compound represented by the following formula (1-1).
    Figure JPOXMLDOC01-appb-C000002
     (In the formula, R 1 and R 2 each represent an alkyl group different from each other. R 1 and R 2 each independently represent a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R 1 are the same as each other. Or t-Bu represents a tertiary butyl group.
  4. 　前記工程では、原子層堆積法又は化学気相蒸着法により前記酸化アルミニウム膜を形成する、請求項１～３のいずれか一項に記載の酸化アルミニウム膜の製造方法。 The method for producing an aluminum oxide film according to any one of claims 1 to 3, wherein in the step, the aluminum oxide film is formed by an atomic layer deposition method or a chemical vapor deposition method.
  5. 　下記式（１）で示されるアルミニウム化合物を含む、酸化アルミニウム膜の製造原料。
    Figure JPOXMLDOC01-appb-C000003
     （式中、Ｒは炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲは互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。）     A raw material for producing an aluminum oxide film containing an aluminum compound represented by the following formula (1).
    Figure JPOXMLDOC01-appb-C000003
     (Wherein R represents a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R may be the same or different from each other. T-Bu represents a tertiary butyl group.)
  6. 　前記アルミニウム化合物は、下記式（１－１）で示される化合物を含む、請求項５に記載の酸化アルミニウム膜の製造原料。
    Figure JPOXMLDOC01-appb-C000004
     　（式中、Ｒ１及びＲ２は互いに異なるアルキル基である。Ｒ１及びＲ２は、それぞれ独立に炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲ１は互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。）     6. The raw material for producing an aluminum oxide film according to claim 5, wherein the aluminum compound includes a compound represented by the following formula (1-1).
    Figure JPOXMLDOC01-appb-C000004
     (Wherein R 1 and R 2 are alkyl groups different from each other. R 1 and R 2 each independently represent a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R 1 are the same as each other) Or t-Bu represents a tertiary butyl group.
  7. 　下記の式（１－１）で示される、アルミニウム化合物。
    Figure JPOXMLDOC01-appb-C000005
     　（式中、Ｒ１及びＲ２は互いに異なるアルキル基を示す。Ｒ１及びＲ２は、それぞれ独立に炭素原子数１～２の直鎖状のアルキル基を示し、複数のＲ１は互いに同一又は異なっていてもよい。ｔ－Ｂｕはターシャリーブチル基を示す。）
          An aluminum compound represented by the following formula (1-1).
    Figure JPOXMLDOC01-appb-C000005
     (In the formula, R 1 and R 2 each represent an alkyl group different from each other. R 1 and R 2 each independently represent a linear alkyl group having 1 to 2 carbon atoms, and a plurality of R 1 are the same as each other. Or t-Bu represents a tertiary butyl group.
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