JP2013166965A - Material for forming aluminum nitride-based thin film and method for producing the thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material for forming a thin film suitable for forming an aluminum nitride-based thin film by a chemical vapor deposition method and a method for producing the thin film excellent in productivity and capable of safely producing the good-quality aluminum nitride-based thin film.SOLUTION: A material for forming an aluminum nitride-based thin film contains an aluminum compound represented by chemical formula (I). In a method for producing the thin film, vapor containing the aluminum compound is obtained by evaporating the material for forming the thin film, the vapor is introduced into a deposition chamber in which a substrate is placed, and the aluminum nitride-based thin film is formed on the surface of the substrate by the degradation and/or chemical reaction of the aluminum compound.

Description

  The present invention relates to a raw material for forming an aluminum nitride thin film containing an aluminum compound having a specific organic ligand, and a method for producing a thin film using the raw material to form an aluminum nitride thin film.

  Aluminum nitride-based thin films are used as heat sink members, electronic device members, and semiconductor members, and are also used in the manufacture of heat dissipation substrates such as ICs, LEDs and laser elements, FET barrier layers, and solar cell materials The use as is expected.

  Examples of the method for producing the thin film include a sputtering method, an ion plating method, a MOD method such as a coating pyrolysis method and a sol-gel method, a chemical vapor deposition method, etc., but has excellent composition controllability and step coverage. Since it has many advantages such as being suitable for mass production and being capable of hybrid integration, it is a chemical vapor deposition (hereinafter sometimes simply referred to as CVD) method including an ALD (Atomic Layer Deposition) method. Is the optimal manufacturing process.

Patent Document 1 discloses an amidinate compound as an aluminum source. However, since the aluminum amidinate compound described in Patent Document 1 has low vapor pressure characteristics, there is a problem that productivity is poor when the aluminum amidinate compound is used as a raw material for chemical vapor deposition. It was.
Patent Document 2 discloses a method for producing an aluminum nitride thin film by MOCVD, and trimethylaluminum and triethylaluminum are disclosed as aluminum sources. However, since the trialkylaluminum disclosed in Patent Document 2 is pyrophoric, it has a safety problem.
Non-Patent Document 1 exemplifies an aluminum compound used in the present invention as an ALD material for producing an aluminum oxide thin film. However, there is no illustration as a raw material for chemical vapor deposition used for manufacturing an aluminum nitride-based thin film.

JP-T-2006-511716 JP 07-305172 A Chem. Mater., Vol.20, No.23, 2008,7287-7291

  In the manufacturing method of a thin film for forming an aluminum nitride thin film using chemical vapor deposition, what is required of the manufacturing method is that the aluminum raw material to be used has no spontaneous ignition and can be manufactured safely. It can be done. Further, the raw material has good thermal decomposability and / or reactivity with a reactive gas, and is excellent in productivity. In addition, in order to improve the quality of the thin film, oxygen and carbon are less mixed in the obtained aluminum nitride thin film. In particular, when an aluminum nitride-based thin film is formed by the ALD method, the vapor containing the aluminum compound obtained by vaporizing the raw material is excellent in adsorbability on the substrate surface in order to improve productivity. It was sought after. In the conventional raw material for forming an aluminum nitride thin film and the method for producing an aluminum nitride thin film, there has been no raw material and production method that are sufficiently satisfactory in these respects.

  As a result of repeated studies, the present inventors use an aluminum nitride-based thin film forming raw material containing an aluminum compound having a specific organic ligand, and use the aluminum nitride-based thin film as the raw material. The present inventors have found that a method for producing a thin film formed by the method can solve the above problems, and have reached the present invention.

The present invention provides an aluminum nitride-based thin film forming raw material containing an aluminum compound represented by the following chemical formula (I).

  The present invention uses the aluminum compound represented by the chemical formula (I) as a raw material for forming a thin film, vaporizes the raw material to obtain a vapor containing the aluminum compound, and the vapor is formed into a component on which a substrate is installed. The present invention provides a method for producing a thin film, which is introduced into a film chamber and decomposes and / or chemically reacts with the aluminum compound to form an aluminum nitride-based thin film on the surface of the substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the raw material for thin film formation suitable for the chemical vapor deposition method used in order to form an aluminum nitride type thin film can be provided, and also it is excellent in productivity and the quality aluminum nitride type thin film. Can be manufactured safely.

FIG. 1 is a schematic diagram showing an example of an apparatus for chemical vapor deposition used in the method for producing an aluminum nitride thin film according to the present invention. FIG. 2 is a schematic view showing another example of an apparatus for chemical vapor deposition used in the method for producing an aluminum nitride thin film according to the present invention. FIG. 3 is a schematic diagram showing another example of an apparatus for chemical vapor deposition used in the method for producing an aluminum nitride thin film according to the present invention. FIG. 4 is a schematic diagram showing another example of an apparatus for chemical vapor deposition used in the method for producing an aluminum nitride thin film according to the present invention.

  The aluminum nitride-based thin film in the present invention is not particularly limited and may be any nitride thin film containing Al atoms. For example, an aluminum nitride thin film; a composite metal nitride such as InAlN, AlGaN, or InAlN Examples include thin films.

  The raw material for forming a thin film of the present invention is a precursor for chemical vapor deposition for forming an aluminum nitride-based thin film using the aluminum compound represented by the above chemical formula (I). It depends on the manufacturing process to which the thin film forming raw material is applied. For example, when manufacturing an aluminum nitride thin film, the raw material for forming a thin film of the present invention does not contain a metal compound and a metalloid compound other than the aluminum compound. On the other hand, when producing a nitride thin film containing aluminum and a metal other than aluminum and / or a metalloid, the raw material for forming a thin film of the present invention includes a compound containing a metal other than aluminum and / or the above-mentioned aluminum compound. Contains a compound containing a metalloid (hereinafter also referred to as other precursor). As will be described later, the thin film forming raw material of the present invention may further contain an organic solvent and / or a nucleophilic reagent. As described above, the thin film forming raw material of the present invention is suitable for the chemical vapor deposition method because the physical properties of the aluminum compound represented by the chemical formula (I), which is a precursor, are suitable for the CVD method and the ALD method. It is useful as (hereinafter sometimes referred to as a CVD raw material).

  The aluminum compound represented by the chemical formula (I) is not particularly limited by the production method, and is produced by applying a known reaction. As a production method, for example, trimethylaluminum can be obtained by reacting an organic compound represented by the following chemical formula (II).

  The form of the raw material for forming a thin film according to the present invention is appropriately selected according to the method such as the CVD transport method used.

  As the above transportation and supply method, the raw material for CVD is vaporized by heating and / or decompressing in a container in which the raw material is stored (hereinafter sometimes simply referred to as a raw material container), and is necessary. A gas transport method in which the vapor is introduced into a film forming chamber in which the substrate is installed, together with a carrier gas such as argon, nitrogen, and helium used according to the conditions, and the CVD raw material is transported to the vaporization chamber in a liquid or solution state. In addition, there is a liquid transport method in which vaporization is performed by heating and / or decompressing in a vaporization chamber to form vapor, and the vapor is introduced into a film formation chamber. In the case of the gas transport method, the aluminum compound itself represented by the chemical formula (I) can be used as a CVD raw material. In the case of the liquid transport method, the aluminum compound itself represented by the chemical formula (I) or a solution obtained by dissolving the compound in an organic solvent can be used as a raw material for CVD. These CVD raw materials may further contain other precursors, nucleophilic reagents, and the like.

In the multi-component CVD method, the CVD raw material is vaporized and supplied independently for each component (hereinafter sometimes referred to as a single source method), and the multi-component raw material is mixed in advance with a desired composition. There is a method of vaporizing and supplying a mixed raw material (hereinafter, sometimes referred to as a cocktail sauce method). In the case of the cocktail source method, a mixture of an aluminum compound represented by the above chemical formula (I) and another precursor or a mixed solution obtained by dissolving the mixture in an organic solvent can be used as a raw material for CVD. This mixture or mixed solution may further contain a nucleophilic reagent and the like.
When a mixture or mixed solution of the aluminum compound represented by the above chemical formula (I) and another precursor is used as a raw material for CVD, the mixing ratio of the two is appropriately selected according to the desired thin film composition. Is preferably selected from the range of 0.05 to 3 mol, more preferably from 0.1 to 2 mol, relative to 1 mol of the aluminum compound.

  As said organic solvent, it does not receive a restriction | limiting in particular, A well-known general organic solvent can be used. Examples of the organic solvent include alcohols such as methanol, ethanol, isopropyl alcohol, and n-butanol; acetates such as ethyl acetate, butyl acetate, and methoxyethyl acetate; tetrahydrofuran, tetrahydropyran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, Ethers such as triethylene glycol dimethyl ether, dibutyl ether, dioxane; ketones such as methyl butyl ketone, methyl isobutyl ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone, methyl amyl ketone, cyclohexanone, methylcyclohexanone; hexane, cyclohexane, Methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, heptane, octane, toluene Hydrocarbons such as xylene; 1-cyanopropane, 1-cyanobutane, 1-cyanohexane, cyanocyclohexane, cyanobenzene, 1,3-dicyanopropane, 1,4-dicyanobutane, 1,6-dicyanohexane, 1, Hydrocarbons having a cyano group such as 4-dicyanocyclohexane and 1,4-dicyanobenzene; pyridine, lutidine, etc. are mentioned, and these are determined solely by the solubility of the solute, the relationship between the use temperature and boiling point, the flash point, etc. Or it is used as a 2 or more types of mixed solvent. When these organic solvents are used, the total amount of the precursor in the CVD raw material, which is a solution obtained by dissolving the precursor in the organic solvent, is 0.01 to 2.0 mol / liter, particularly 0.05 to 1.0 mol / liter. It is preferable to make it liter. The amount of the entire precursor is represented by the above chemical formula (I) when the thin film forming raw material of the present invention does not contain a metal compound and a semimetal compound other than the aluminum compound represented by the above chemical formula (I). When the thin film forming raw material of the present invention contains a compound containing a metal other than aluminum and / or a compound containing a metalloid in addition to the aluminum compound represented by the above chemical formula (I) The total amount of the aluminum compound represented by the above chemical formula (I) and other precursors.

  In the case of a multi-component CVD method, the other precursor used together with the aluminum compound represented by the chemical formula (I) is not particularly limited, and is a well-known general precursor used as a raw material for CVD. Can be used. The ligand used in the precursor is preferably one that does not contain an oxygen atom in the structure, and one that further contains a nitrogen atom in the structure reduces the amount of oxygen mixed in the resulting aluminum nitride-based thin film. preferable.

  The other precursor is one or more selected from the group consisting of compounds used as organic ligands such as alcohol compounds, glycol compounds, β-diketone compounds, cyclopentadiene compounds, and organic amine compounds. A compound with silicon or metal (except aluminum) can be used. The precursor metal species include magnesium, calcium, strontium, barium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, manganese, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver , Gold, zinc, gallium, indium, germanium, tin, lead, antimony, bismuth, scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium , Lutetium.

  Examples of the alcohol compound used as the organic ligand include methanol, ethanol, propanol, isopropyl alcohol, butanol, secondary butyl alcohol, isobutyl alcohol, tertiary butyl alcohol, pentyl alcohol, isopentyl alcohol, and tertiary pentyl alcohol. 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2- (2-methoxyethoxy) ethanol, 2-methoxy-1-methylethanol, 2-methoxy-1,1-dimethylethanol, 2-ethoxy-1,1-dimethylethanol, 2-isopropoxy-1,1-dimethylethanol, 2-butoxy-1,1-dimethylethanol, 2- (2-methoxyethoxy) -1,1-dimethylethanol , 2-propoxy-1,1-diethylethanolamine, 2-s-butoxy-1,1-diethyl ethanol, ether alcohols such as 3-methoxy-1,1-dimethyl propanol.

  Examples of the glycol compound used as the organic ligand of the other precursor include 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 2,4-hexanediol, 2,2- Dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,3-butanediol, 2,4-butanediol, 2,2-diethyl-1,3-butanediol, 2 -Ethyl-2-butyl-1,3-propanediol, 2,4-pentanediol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 2,4-hexanediol, 2,4-dimethyl-2,4-pentanediol and the like can be mentioned.

  Examples of the β-diketone compound include acetylacetone, hexane-2,4-dione, 5-methylhexane-2,4-dione, heptane-2,4-dione, 2-methylheptane-3,5-dione, 5 -Methylheptane-2,4-dione, 6-methylheptane-2,4-dione, 2,2-dimethylheptane-3,5-dione, 2,6-dimethylheptane-3,5-dione, 2,2 , 6-trimethylheptane-3,5-dione, 2,2,6,6-tetramethylheptane-3,5-dione, octane-2,4-dione, 2,2,6-trimethyloctane-3,5 -Dione, 2,6-dimethyloctane-3,5-dione, 2,9-dimethylnonane-4,6-dione, 2-methyl-6-ethyldecane-3,5-dione, 2,2-dimethyl -6-ethylde Alkyl-substituted β-diketones such as 1,3,5-dione; 1,1,1-trifluoropentane-2,4-dione, 1,1,1-trifluoro-5,5-dimethylhexane-2, Fluorine-substituted alkyl β-diketones such as 4-dione, 1,1,1,5,5,5-hexafluoropentane-2,4-dione, 1,3-diperfluorohexylpropane-1,3-dione 1,1,5,5-tetramethyl-1-methoxyhexane-2,4-dione, 2,2,6,6-tetramethyl-1-methoxyheptane-3,5-dione, 2,2,6; , 6-tetramethyl-1- (2-methoxyethoxy) heptane-3,5-dione and the like ether-substituted β-diketones.

  Cyclopentadiene compounds include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, isopropylcyclopentadiene, butylcyclopentadiene, second butylcyclopentadiene, isobutylcyclopentadiene, tert-butylcyclopentadiene, dimethylcyclopentadiene. And tetramethylcyclopentadiene.

  Examples of the organic amine compound used as the organic ligand include a ketimine compound, an amidinate compound, methylamine, ethylamine, propylamine, isopropylamine, butylamine, secondary butylamine, tertiary butylamine, isobutylamine, dimethylamine, diethylamine, Examples include dipropylamine, diisopropylamine, ethylmethylamine, propylmethylamine, isopropylmethylamine, and bis (trimethylsilyl) amine.

  Other precursors described above are known in the art, and their production methods are also known. As an example of the production method, for example, when an alcohol compound is used as the organic ligand, the inorganic salt of metal or its hydrate described above is reacted with the alkali metal alkoxide of the alcohol compound. Thus, a precursor can be manufactured. Here, examples of the metal inorganic salt or hydrate include metal halides and nitrates, and examples of the alkali metal alkoxide include sodium alkoxide, lithium alkoxide, and potassium alkoxide.

  In the case of the single source method, the other precursor is preferably a compound similar in behavior to heat and / or oxidative decomposition with the aluminum compound represented by the above chemical formula (I). In addition to the similar behavior of heat and / or oxidative decomposition, those that do not undergo alteration due to chemical reaction during mixing are preferred.

  Moreover, the raw material for forming a thin film of the present invention may contain a nucleophilic reagent as needed to impart stability of the raw material. Examples of the nucleophilic reagent include ethylene glycol ethers such as glyme, diglyme, triglyme and tetraglyme, 18-crown-6, dicyclohexyl-18-crown-6, 24-crown-8, dicyclohexyl-24-crown-8. , Crown ethers such as dibenzo-24-crown-8, ethylenediamine, N, N′-tetramethylethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, 1,1,4,7,7- Polyamines such as pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetramine and triethoxytriethyleneamine, cyclic polyamines such as cyclam and cyclen, pyridine, pyrrolidine and piperi Heterocyclic compounds such as gin, morpholine, N-methylpyrrolidine, N-methylpiperidine, N-methylmorpholine, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, oxazole, thiazole, oxathiolane, methyl acetoacetate, ethyl acetoacetate, Β-ketoesters such as acetoacetate-2-methoxyethyl or β-diketones such as acetylacetone, 2,4-hexanedione, 2,4-heptanedione, 3,5-heptanedione, and dipivaloylmethane The amount of these nucleophilic reagents used is preferably in the range of 0.1 mol to 10 mol, more preferably 1 to 4 mol, relative to 1 mol of the aluminum compound represented by the chemical formula (I). When these nucleophilic reagents are used, those having no oxygen atom in the structure of the nucleophilic reagent are preferable, and those having a nitrogen atom in the structure are particularly preferable.

  The raw material for forming a thin film of the present invention contains as little impurities metal elements as possible, impurities halogen such as impurity chlorine, and organic impurities as much as possible. The impurity metal element content is preferably 100 ppb or less for each element, more preferably 10 ppb or less, and the total amount is preferably 1 ppm or less, more preferably 100 ppb or less. In particular, when used as an LSI gate insulating film, gate film, or barrier layer, the content of alkali metal elements, alkaline earth metal elements, and related elements that affect the electrical characteristics of the resulting thin film should be reduced. is necessary. The impurity halogen content is preferably 100 ppm or less, more preferably 10 ppm or less, and still more preferably 1 ppm or less. The total amount of impurity organic components is preferably 500 ppm or less, more preferably 50 ppm or less, and still more preferably 10 ppm or less. Moreover, since moisture causes generation of particles in the raw material for chemical vapor deposition and generation of particles during thin film formation, the aluminum compound represented by the chemical formula (I), other precursors, organic solvents, and For nucleophilic reagents, it is better to remove water as much as possible before use in order to reduce the water content. The water content of each of the aluminum compound represented by the chemical formula (I), the other precursor, the organic solvent and the nucleophilic reagent is preferably 10 ppm or less, and more preferably 1 ppm or less.

  Moreover, it is preferable that the raw material for forming a thin film of the present invention contains particles as little as possible in order to reduce or prevent particle contamination of the formed thin film. Specifically, in the particle measurement by the light scattering liquid particle detector in the liquid phase, the number of particles larger than 0.3 μm is preferably 100 or less in 1 ml of the liquid phase, and larger than 0.2 μm. The number of particles is more preferably 1000 or less in 1 ml of the liquid phase, and the number of particles larger than 0.2 μm is further preferably 100 or less in 1 ml of the liquid phase.

  As a method for producing a thin film for forming an aluminum nitride-based thin film of the present invention, a substrate was provided with vapor obtained by vaporizing the aluminum compound represented by the above chemical formula (I) and a reactive gas used as necessary. The film is introduced into the film formation chamber, and then the precursor is decomposed and / or chemically reacted on the substrate and / or in the film formation chamber and / or in the vicinity of the gas inlet to grow and deposit an aluminum nitride thin film on the surface of the substrate. This is due to the CVD method. There are no particular restrictions on the method of transporting and supplying the raw material, the deposition method, the production conditions, the production apparatus, etc., and well-known general conditions and methods can be used.

  Examples of the reactive gas used as necessary include organic amine compounds such as monoalkylamines, dialkylamines, trialkylamines, and alkylenediamines, and compounds having a nitrogen atom in the structure such as hydrazine, ammonia, and nitrogen. These gases and hydrogen gas can be used, and one kind or two or more kinds can be used. In addition, plasma treatment can be performed before the reactive gas reacts with the precursor.

  Examples of the transport and supply method include the gas transport method, the liquid transport method, the single source method, and the cocktail sauce method described above.

  Further, as the above deposition method, thermal CVD in which a raw material gas or a raw material gas and a reactive gas are reacted only by heat to deposit a thin film, plasma CVD using heat and plasma, photo CVD using heat and light, Examples include optical plasma CVD using heat, light, and plasma, and ALD in which the deposition reaction of CVD is divided into elementary processes and deposition is performed stepwise at the molecular level.

  Examples of the material of the substrate include silicon; indium arsenide, indium gallium arsenide, silicon oxide, silicon nitride, silicon carbide, titanium nitride, tantalum oxide, tantalum nitride, titanium oxide, titanium nitride, ruthenium oxide, zirconium oxide, hafnium oxide, Ceramics such as lanthanum oxide and gallium nitride; glass; metals such as platinum ruthenium, aluminum, copper, nickel, cobalt, tungsten, and molybdenum. Examples of the shape of the substrate include a plate shape, a spherical shape, a fiber shape, and a scale shape, and the surface of the substrate may be a flat surface or a three-dimensional structure such as a trench structure.

  Moreover, as said manufacturing conditions, reaction temperature (base | substrate temperature), reaction pressure, a deposition rate, etc. are mentioned. About reaction temperature, 100 degreeC or more which is the temperature which the aluminum compound represented by the said Chemical formula (I) fully reacts is preferable, and 150 to 400 degreeC is more preferable. The reaction pressure is preferably atmospheric pressure to 10 Pa in the case of thermal CVD or photo CVD, and preferably 2000 Pa to 10 Pa in the case of using plasma. The deposition rate can be controlled by the raw material supply conditions (vaporization temperature, vaporization pressure), reaction temperature, and reaction pressure. When the deposition rate is large, the properties of the obtained thin film may be deteriorated. When the deposition rate is small, a problem may be caused in productivity. Therefore, 0.01 to 100 nm / min is preferable, and 1 to 50 nm / min is more preferable. In the case of the ALD method, the number of cycles is controlled so as to obtain a desired film thickness.

  The production conditions further include temperature and pressure when the thin film forming raw material is vaporized into steam. The step of vaporizing the raw material for forming a thin film to form a vapor may be performed in a raw material container or in a vaporization chamber. In any case, it is preferable that the raw material for forming a thin film used in the method for producing a thin film for forming the aluminum nitride thin film of the present invention is evaporated at 0 to 150 ° C. In addition, when the thin film forming raw material is vaporized in the raw material container or in the vaporization chamber to form a vapor, the pressure in the raw material container and the pressure in the vaporization chamber are both preferably 1 to 10,000 Pa.

  The thin film manufacturing method of the present invention adopts the ALD method, vaporizes the raw material for forming the thin film into the vapor by the above-described transport and supply method, and introduces the vapor into the film forming chamber. A precursor thin film forming step of forming a precursor thin film on the surface of the substrate by the aluminum compound represented by the chemical formula (I) in the vapor; an unreacted aluminum compound gas represented by the chemical formula (I) And an aluminum nitride thin film forming step of forming an aluminum nitride thin film on the surface of the substrate by chemically reacting the precursor thin film with a reactive gas.

Hereinafter, each of the above steps will be described in detail by taking as an example the case of forming an aluminum nitride-based thin film. When forming the aluminum nitride thin film by the ALD method, first, the raw material introduction step described above is performed. Preferred temperatures and pressures when the thin film forming raw material is steam are the same as those described above. Next, a precursor thin film is formed on the surface of the substrate with the aluminum compound represented by the above chemical formula (I) introduced into the film forming chamber (precursor thin film forming step). At this time, heat may be applied by heating the substrate or heating the inside of the film formation chamber.
The precursor thin film formed in this step is formed by adsorbing the aluminum compound represented by the above chemical formula (I) on the substrate surface, or by decomposing and / or reacting the compound or a part of the compound. It is a thin film and has a composition different from the target aluminum nitride-based thin film. The substrate temperature when this step is performed is preferably room temperature to 600 ° C, more preferably 150 to 400 ° C. The pressure of the system (in the film forming chamber) when this step is performed is preferably 1 to 10,000 Pa, and more preferably 10 to 1000 Pa.

  Next, the unreacted aluminum compound gas represented by the chemical formula (I) and by-produced gas are exhausted from the film forming chamber (exhaust process). Although it is ideal that the unreacted aluminum compound gas represented by the chemical formula (I) or the by-product gas is completely exhausted from the film forming chamber, it is not always necessary to exhaust it completely. Examples of the exhaust method include a method of purging the system with an inert gas such as nitrogen, helium, and argon, a method of exhausting the system by depressurizing the system, a method combining these, and the like. When the pressure is reduced, the degree of pressure reduction is preferably 0.01 to 300 Pa, and more preferably 0.01 to 100 Pa.

  Next, a reactive gas is introduced into the film forming chamber, and an aluminum nitride thin film is formed from the precursor thin film obtained in the previous precursor thin film forming step by the action of the reactive gas or the reactive gas and heat. (Aluminum nitride thin film forming step). The substrate temperature when heat is applied in this step is preferably from room temperature to 600 ° C, more preferably from 150 to 400 ° C. The pressure of the system (in the film forming chamber) when this step is performed is preferably 1 to 10,000 Pa, and more preferably 10 to 1000 Pa.

  In the thin film manufacturing method of the present invention, when the ALD method is employed as described above, a series of operations including the raw material introduction step, the precursor thin film formation step, the exhaust step, and the aluminum nitride-based thin film formation step are performed. The thin film deposition may be one cycle, and this cycle may be repeated a plurality of times until a thin film having a required film thickness is obtained. In this case, after one cycle, unreacted aluminum compound gas and reactive gas represented by the chemical formula (I) and further by-produced gas were exhausted from the film forming chamber in the same manner as the exhaust process. Thereafter, it is preferable to perform the next one cycle.

  In the method for producing a thin film of the present invention, when the ALD method is employed as described above, energy such as plasma, light, voltage, etc. may be applied, or a catalyst may be used. The timing for applying these energies is not particularly limited. For example, when introducing an aluminum compound gas in the raw material introduction step, heating in the precursor thin film formation step or aluminum nitride thin film formation step, and in the system in the exhaust step At the time of evacuation, the reactive gas may be introduced in the aluminum nitride thin film forming step, or may be between the above steps. In addition, these energies can be applied to the reactive gas before introducing the reactive gas.

  Further, in the thin film manufacturing method of the present invention, when the plasma ALD method is employed as described above, the reactive gas may continue to flow into the film forming chamber during all steps in the manufacturing method. Only in the thin film forming process, a plasma treatment performed on the reactive gas may be introduced into the film forming chamber. Whether applied to the reactive gas before being introduced into the film forming chamber or applied to the reactive gas after being introduced into the film forming chamber, the high frequency ( Hereinafter, the output may be referred to as RF). If the output is too low, it is difficult to form a good nitride film. If the output is too high, damage to the substrate is large, and therefore 0 to 1500 W is preferable, and 100 to 600 W is more preferable.

  In the thin film manufacturing method of the present invention, after thin film deposition, annealing may be performed in an inert atmosphere in order to obtain better electrical characteristics. May be provided. The temperature in this case is 200 to 1000 ° C, preferably 250 to 500 ° C.

  A known chemical vapor deposition apparatus can be used as an apparatus for producing an aluminum nitride-based thin film using the thin film forming raw material of the present invention. Specific examples of the apparatus include an apparatus that can perform a precursor as shown in FIG. 1 by bubbling supply, and an apparatus that has a vaporization chamber as shown in FIG. Moreover, as shown in FIG.3 and FIG.4, the apparatus which can perform a plasma process with respect to reactive gas is mentioned. The present invention is not limited to the single wafer type apparatus as shown in FIGS. 1, 2, 3 and 4, and an apparatus capable of simultaneously processing a large number of sheets using a batch furnace can also be used.

  The aluminum nitride-based thin film produced using the raw material for forming a thin film of the present invention is used as a heat sink member, a member for an electronic device, or a member for a semiconductor, and is used for manufacturing a heat dissipation substrate such as an IC, an LED, or a laser element. Can also be used for FET barrier layers and solar cell materials.

  Hereinafter, the present invention will be described in more detail with examples and evaluation examples. However, the present invention is not limited by the following examples.

[Evaluation Example 1]
The presence or absence of pyrophoric properties was confirmed by leaving the compound represented by the above chemical formula (I) and the following comparative compounds 1 and 2 in the air. The results are shown in Table 1.

  From the results in Table 1, it was found that Comparative Compound 1 exhibits spontaneous ignition in the atmosphere. A compound exhibiting pyrophoric properties is unsuitable as a raw material for vapor phase growth in the production of an aluminum nitride thin film from the viewpoint of safety. It was found that the aluminum compound represented by the chemical formula (I) and the comparative compound 2 did not show pyrophoric properties and could be used safely in the air as a raw material for chemical vapor deposition. From the above, it has been found that when the aluminum compound represented by the chemical formula (I) or the comparative compound 2 is used as a raw material for chemical vapor deposition, an aluminum nitride-based thin film can be produced safely.

[Example 1]
An aluminum nitride thin film was produced on the surface of the silicon wafer by the ALD method under the following conditions using the aluminum compound represented by the chemical formula (I) as a raw material for chemical vapor deposition and using the apparatus shown in FIG. About the obtained thin film, when the film thickness measurement by the X-ray reflectivity method, the thin film structure and the thin film composition were confirmed by the X-ray diffraction method and the X-ray photoelectron spectroscopy, the film thickness was 4.0 nm. Was aluminum nitride, and the carbon content was less than the detection lower limit of 0.1 atom%. The film thickness obtained per cycle was 0.08 nm.
(conditions)
Reaction temperature (substrate temperature): 240 ° C., reactive gas: ammonia (process)
A series of steps consisting of the following (1) to (4) was set as one cycle and repeated 50 cycles.
(1) The vapor of the chemical vapor deposition raw material vaporized under the conditions of the raw material container temperature: 25 ° C. and the raw material container pressure: 0.6 Torr (80 Pa) is introduced into the film forming chamber, and the system pressure is 0.5 Torr ( 67 Pa) for 5 seconds.
(2) The unreacted raw material is removed from the film forming chamber by argon purging for 20 seconds.
(3) A reactive gas is introduced into the film forming chamber and reacted at a system pressure of 0.5 Torr (67 Pa) for 5 seconds. At this time, plasma is generated by applying a high frequency output of 13.56 MHz and 500 W to the reactive gas.
(4) The unreacted raw material is removed from the film forming chamber by argon purging for 15 seconds.

[Comparative Example 1]
A comparative compound 2 was used as a raw material for chemical vapor deposition, and an aluminum nitride thin film was produced on a silicon wafer by the ALD method under the following conditions using the apparatus shown in FIG. About the obtained thin film, when the film thickness measurement by the X-ray reflectivity method, the thin film structure and the thin film composition were confirmed by the X-ray diffraction method and the X-ray photoelectron spectroscopy, the film thickness was 2.0 nm. Was aluminum nitride and the carbon content was 1 atom%. The film thickness obtained per cycle was 0.04 nm.
(conditions)
Reaction temperature (substrate temperature): 240 ° C., reactive gas: ammonia (process)
A series of steps consisting of the following (1) to (4) was set as one cycle and repeated 50 cycles.
(1) The vapor of the chemical vapor deposition raw material vaporized under the conditions of the raw material container temperature: 25 ° C. and the raw material container pressure: 0.6 Torr (80 Pa) is introduced into the film forming chamber, and the system pressure is 0.5 Torr ( 67 Pa) for 5 seconds.
(2) The unreacted raw material is removed from the film forming chamber by argon purging for 20 seconds.
(3) A reactive gas is introduced into the film forming chamber and reacted at a system pressure of 0.5 Torr (67 Pa) for 5 seconds. At this time, plasma is generated by applying a high frequency output of 13.56 MHz and 500 W to the reactive gas.
(4) The unreacted raw material is removed from the film forming chamber by argon purging for 15 seconds.

  From the results of Example 1 and Comparative Example 1, an aluminum nitride thin film can be produced by using the thin film forming raw material of the present invention, and the obtained aluminum nitride thin film has Comparative Compound 2 as a thin film forming raw material. Since the film thickness obtained per cycle is twice as large as when used, and the carbon impurities in the obtained film are also 1/10 or less, the production of the aluminum nitride thin film of the present invention is carried out. It has been found that the method can produce an aluminum nitride thin film with good productivity and quality.

Claims (2)

A raw material for forming an aluminum nitride thin film comprising an aluminum compound represented by the following chemical formula (I).

  The raw material for forming a thin film according to claim 1 is vaporized to obtain a vapor containing the aluminum compound, the vapor is introduced into a film forming chamber in which a substrate is installed, and the aluminum compound is decomposed and / or A method for producing a thin film, wherein an aluminum nitride thin film is formed on the surface of the substrate by chemical reaction.

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