WO2022014344A1

WO2022014344A1 - Thin film-forming material, thin film, and thin film producing method

Info

Publication number: WO2022014344A1
Application number: PCT/JP2021/024953
Authority: WO
Inventors: 雅子畑▲瀬▼; 千瑛満井; 奈奈岡田; 敦史山下
Original assignee: 株式会社Adeka
Priority date: 2020-07-13
Filing date: 2021-07-01
Publication date: 2022-01-20
Also published as: TW202212343A; JPWO2022014344A1

Abstract

Provided is a thin film-forming material containing a yttrium compound represented by general formula (1).　(In the formula, R¹ and R³ each independently represent an alkyl group having 1-6 carbon atoms or an alkoxyalkyl group having 2-6 carbon atoms, R² represents a hydrogen atom or an alkyl group having 1-3 carbon atoms, R⁴ represents an alkanediyl group having 1-5 carbon atoms, R⁵ represents an alkyl group each having 1-3 carbon atoms, and R¹, R², R³, R⁴, and R⁵, which are each present in a number of more than one, may be the same or different within each other.)

Description

Raw materials for thin film formation, thin films and methods for manufacturing thin films

The present invention relates to a raw material for forming a thin film containing an yttrium compound having a specific structure, a thin film obtained by using the raw material, and a method for producing the same.

In the semiconductor manufacturing industry, a metal-containing complex is being studied as a raw material for forming a thin film capable of forming a thin film such as a metal nitride, a metal oxide, or a metal-containing film on a substrate such as silicon.

Yttrium is used as a component for constituting a compound semiconductor, and various compounds have been reported as a raw material for forming a thin film for producing a thin film containing yttrium.

Examples of the thin film manufacturing method include a sputtering method, an ion plating method, a metal organic compound decomposition (MOD: Metal Organic Decomposition) method such as a coating thermal decomposition method and a solgel method, and a chemical vapor deposition (CVD). Examples include the method, atomic layer deposition (ALD: Atomic Layer Deposition) method, and the like. Among these, the CVD method and the ALD method are mainly used because the quality of the obtained thin film is good.

Various thin film forming raw materials that can be used in vapor phase thin film forming methods such as the CVD method and the ALD method have been reported, but the thin film forming raw materials applicable to the ALD method have a temperature region called an ALD window. It is necessary to have sufficient space. It is common general knowledge in the art that even a thin film forming raw material that can be used in the CVD method is not suitable for the ALD method in many cases.

As a raw material for forming a thin film for forming a thin film containing yttrium, for example, in Patent Document 1, -R ^4- NR ⁵ R ⁶ (R ⁴ is an alkylene crosslinked group, and R ⁵ and R ^{6 are formed on the N side chain.} Has been proposed as a metal-containing complex having a β-ketominate structure (selected from an alkyl group and the like).

Patent Document 2 proposes a metal-containing complex containing a polydentate ketoimin ligand and an alkoxy ligand or an amino ligand as a precursor for forming a metal film or a metal oxide film. Has been done.

Patent Document 3 discloses that an yttrium compound having a β-ketoimine ligand is used as a catalyst for conjugated diene polymerization.

Japanese Patent No. 4680953 (Japanese Unexamined Patent Publication No. 2007-302656) Japanese Patent No. 5698161 (Japanese Unexamined Patent Publication No. 2012-153688) Japanese Patent No. 6020257 (Japanese Unexamined Patent Publication No. 2014-166967)

The raw material for thin film formation is required to have a low melting point, high volatility, high thermal stability, and the ability to form a high quality thin film with a small amount of residual carbon. However, the raw materials for forming a thin film containing the yttrium compound proposed in Patent Documents 1 and 2 have not satisfied these requirements.

Patent Document 3 does not contain any description suggesting that an yttrium compound having a β-ketoimine ligand is used as a raw material for forming a thin film.

Therefore, an object of the present invention is to provide a raw material for forming a thin film containing an yttrium compound, which has a low melting point, high volatility and thermal stability, and can be suitably used for a CVD method or an ALD method. .. Another object of the present invention is to provide a thin film obtained by using the thin film forming raw material and a method for producing the same.

As a result of diligent studies, the present inventors have found that a raw material for forming a thin film containing an yttrium compound having a specific structure can solve the above-mentioned problems, and have completed the present invention.
That is, the present invention is a raw material for forming a thin film containing an yttrium compound represented by the following general formula (1) or (2).

(In the formula, R ¹ and R ³ independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 6 carbon atoms, and R ² is a hydrogen atom or 1 carbon atom. ^{R 4} represents an alkyl group having 1 to 3 carbon atoms, R 4 represents an alkyl group having 1 to 5 carbon atoms, R ⁵ represents an alkyl group having 1 to 3 carbon atoms, and a plurality of R ¹ , R ² , and R. ³ , R ⁴ and R ⁵ may be the same or different from each other.)

(In the formula, R ⁶ and R ⁸ independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 6 carbon atoms, and R ⁷ is a hydrogen atom or 1 carbon atom. Representing an alkyl group of ~ 3, the plurality of R ⁶ , R ⁷ and R ⁸ may be the same or different, respectively, except that at least one of ^{R 6} and R ^{8 is carbon.} Represents an alkoxyalkyl group having 2 to 6 atoms.)

In the raw material for forming a thin film of the present invention, in the above general formula (1), R ¹ and R ³ are isopropyl groups, R ² is a hydrogen atom, R ⁴ is an ethylene group, and R ⁵ is a methyl group. A certain yttrium compound, or the yttrium compound in the above general formula (2) in which R ⁶ is a methoxytert-butyl group, R ⁷ is a hydrogen atom, and R ⁸ is an isopropyl group, has a low melting point. It is preferable because of its high volatile and thermal stability.

Further, the present invention is a step of introducing a raw material gas obtained by vaporizing the raw material for forming a thin film into a film forming chamber in which a substrate is installed, and a precursor by depositing an yttrium compound in the raw material gas on the surface of the substrate. A thin film including a step of forming a thin film and a step of introducing a reactive gas into a film forming chamber and reacting the precursor thin film with the reactive gas to form a thin film containing an yttrium atom on the surface of the substrate. It is a manufacturing method of.

Further, in the method for producing a thin film of the present invention, it is preferable that the reactive gas is an oxidizing gas and the thin film containing an yttrium atom is yttrium oxide.

Further, in the method for producing a thin film of the present invention, it is more preferable that the oxidizing gas is a gas containing oxygen, ozone or water vapor.

Further, in the method for producing a thin film of the present invention, it is preferable to react the precursor thin film with the reactive gas in the range of 100 ° C to 400 ° C.

According to the present invention, by containing a specific yttrium compound, it is possible to provide a raw material for forming a thin film having a low melting point and high volatility and thermal stability. Further, by using the raw material for forming a thin film of the present invention, a high-quality yttrium-containing thin film having a small residual carbon content can be produced by using a CVD method, particularly an ALD method.

It is a schematic diagram which shows an example of the ALD apparatus used in the manufacturing method of the thin film which concerns on this invention. It is a schematic diagram which shows another example of the ALD apparatus used in the manufacturing method of the thin film which concerns on this invention. It is a schematic diagram which shows still another example of the ALD apparatus used in the manufacturing method of the thin film which concerns on this invention. It is a schematic diagram which shows still another example of the ALD apparatus used in the manufacturing method of the thin film which concerns on this invention.

<Raw material for thin film formation>
The raw material for forming a thin film of the present invention contains an yttrium compound represented by the above general formula (1) or (2).

In the above general formula (1), R ¹ and R ³ independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 6 carbon atoms, and R ² is a hydrogen atom or ^{R 4} represents an alkyl group having 1 to 3 carbon atoms, R 4 represents an alkylandyl group having 1 to 5 carbon atoms, R ⁵ represents an alkyl group having 1 to 3 carbon atoms, and a plurality of R ¹ ,. R ² , R ³ , R ⁴ and R ⁵ may be the same or different from each other.

In the above general formula (2), R ⁶ and R ⁸ independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 6 carbon atoms, and R ⁷ is a hydrogen atom or a hydrogen atom or Representing an alkyl group having 1 to 3 carbon atoms, the plurality of R ⁶ , R ⁷ and R ⁸ may be the same or different from each other. However, ^{at least one of R 6} and R ⁸ represents an alkoxyalkyl group having 2 to 6 carbon atoms.

Since the yttrium compound represented by the general formula (1) or (2) is used as a precursor for forming a thin film by the CVD method or the ALD method, the melting point is preferably 100 ° C. or lower. It is more preferable that it is liquid at room temperature. Further, the temperature when the yttrium compound is reduced by 50% by mass by a reduced pressure thermogravimetric differential thermal analyzer (TG-DTA) is preferably 240 ° C. or lower.

The thermal decomposition start temperature of the yttrium compound by the differential scanning calorimeter (DSC) is preferably 250 ° C. or higher, and more preferably 300 ° C. or higher.

In the above general formula (1) ^{, examples of the alkyl group having 1 to 6 carbon atoms represented by R 1} and R ³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group and an n-butyl group. Examples thereof include sec-butyl group, tert-butyl group, isobutyl group, n-pentyl group, sec-pentyl group, tert-pentyl group, isopentyl group, neopentyl group and hexyl group. From the viewpoint that the effect of the present invention is remarkable, in the above general formula (1), ^{an yttrium compound in which R 1} and R ³ are alkyl groups having 1 to 4 carbon atoms is preferable, and R ¹ is an ethyl group and isopropyl. An yttrium compound which is a group or a tert-butyl group and R ³ is an ethyl group or an isopropyl group is more preferable, and an yttrium compound in which R ¹ and R ³ are an isopropyl group is most preferable.

In the above general formula (1) ^{, examples of the alkoxyalkyl group having 2 to 6 carbon atoms represented by R 1} and R ³ include a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group and a methoxyisopropyl group. Examples thereof include a group, a methoxypropyl group, a methoxyisobutyl group, a methoxysec-butyl group, a methoxytert-butyl group, an ethoxyisopropyl group, an ethoxybutyl group, an ethoxyisobutyl group, an ethoxysec-butyl group, an ethoxytert-butyl group and the like. From the viewpoint that the effect of the present invention is remarkable ^{, the yttrium compound in which R 1} and R ³ are methoxyisopropyl groups or methoxytert-butyl is preferable in the above general formula (1).

In the above general formula (1), ^{examples of the alkyl group having 1 to 3 carbon atoms represented by R 2} and R ⁵ include the above-mentioned alkyl groups having 1 to 3 carbon atoms. From the viewpoint that the effect of the present invention is remarkable ^{, the yttrium compound in which R 2} is a hydrogen atom and R ⁵ is a methyl group is preferable in the above general formula (1).

In the above general formula (1) ^{, examples of the alkanediyl group having 1 to 5 carbon atoms represented by R 4} include a methylene group, an ethylene group, a propane-1,3-diyl group, and a propane-1,2-. Examples thereof include a diyl group, a butylene group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group and the like. From the viewpoint that the effect of the present invention is remarkable ^{, the yttrium compound in which R 4} is an ethylene group or a propane-1,2-diyl group is preferable in the above general formula (1).

In the above general formula (2), examples of the alkyl group having 1 to 6 carbon atoms and the alkoxyalkyl group having 2 to 6 carbon atoms represented by ^{R 6} and R ^{8 are the same as those described above.}

In the above general formula (2), examples of the alkyl group having 1 to 3 carbon atoms represented by ^{R 7 are the same as those described above.}

In the above general formula (2), the plurality of R ⁶ , R ⁷ and R ⁸ may be the same or different, but at least one of the ^{plurality of R 6} and R ^{8 may be different.} Is an alkoxyalkyl group having 2 to 6 carbon atoms. In the above general formula (2), ^{an yttrium compound in which two or more of the plurality of R 6} and R ⁸ are alkoxyalkyl groups having 2 to 6 carbon atoms is preferable, ^{and three of the plurality of R 6} and R ⁸ are carbon. An yttrium compound which is an alkoxyalkyl group having 2 to 6 atoms is more preferable.

As a preferable specific example of the yttrium compound represented by the above general formula (1) or (2), the following No. 1 to No. 16 yttrium compounds are mentioned, but the invention is not limited to these yttrium compounds. In addition, the following No. 1 to No. In the yttrium compound 16, "Me" represents a methyl group, "Et" represents an ethyl group, "iPr" represents an isopropyl group, and "tBu" represents a tert-butyl group.

Among the above yttrium compounds, from the viewpoint that the effect of the present invention is particularly remarkable, No. 1, No. 3, No. 6 and No. Fifteen yttrium compounds are preferred.

The yttrium compound of the present invention can be produced by utilizing a well-known reaction. For example, in the above general formula (1), R ¹ is a methyl group, R ² is a hydrogen atom, R ³ is a methyl group, R ⁴ is a methylene group, and R ⁵ is a methyl group. The compound can be obtained by reacting ittrium-tris-trimethylsilylamide with 4-methoxymethylamino-3-penten-2-one in a solvent, removing the solvent, and purifying by distillation. Further, in the above general formula (2), the ^{yttrium compound in which R 6} is a methoxytert-butyl group, R ⁷ is a hydrogen atom and R ⁸ is an isopropyl group is an yttrium-tris-trimethylsilylamide in a solvent. It can be obtained by reacting with 5-amino-7-methoxy-4-hepten-3-one, removing the solvent, and purifying by distillation.

The raw material for forming a thin film of the present invention may be any as long as it contains the yttrium compound represented by the above general formula (1) or (2), and its composition varies depending on the type of the target thin film. For example, when producing a thin film containing only yttrium as a metal, the raw material for forming a thin film of the present invention does not contain a compound containing a metal other than yttrium and a compound containing a semimetal. On the other hand, when producing a thin film containing yttrium and a metal other than yttrium and / or a semimetal, the raw material for forming a thin film of the present invention is in addition to the yttrium compound represented by the above general formula (1) or (2). , A compound containing a desired metal and / or a compound containing a semimetal (hereinafter, may be referred to as "another precursor") can be contained.

Further, in the case of a multi-component CVD method using a plurality of precursors, the other precursors that can be used together with the yttrium compound represented by the above general formula (1) or (2) are not particularly limited. A well-known general precursor used as a raw material for forming a thin film for a CVD method can be used.

The other precursors described above include, for example, one or two types 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. The above and compounds with silicon and metals can be mentioned. The metal species of precursors include lithium, sodium, magnesium, aluminum, potassium, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, lutetium, strontium, and ittrium. , Zirconium, niobium, molybdenum, technetium, lutetium, rhodium, palladium, silver, indium, tin, antimony, barium, hafnium, tantalum, tungsten, renium, osmium, iridium, platinum, gold, lead, bismus, radium, lantern, cerium , Praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, itterbium, or lutetium.

Examples of the alcohol compound used as the organic ligand of the other precursors described above include methanol, ethanol, propanol, isopropyl alcohol, butanol, sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, pentyl alcohol and isopentyl alcohol. , Tart-alkyl alcohols such as 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-diethylethanol, 2-sec-butoxy-1,1-diethylethanol, 3-methoxy-1,1-dimethylpropanol and other ether alcohols; dimethylaminoethanol, Ethylmethylaminoethanol, diethylaminoethanol, dimethylamino-2-pentanol, ethylmethylamino-2-pentanol, dimethylamino-2-methyl-2-pentanol, ethylmethylamino-2-methyl-2-pentanol, Examples thereof include dialkylaminoalcohols such as diethylamino-2-methyl-2-pentanol.

Examples of the glycol compound used as the organic ligand of the other precursors described above include 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 2,4-hexanediol, and 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-hexane Examples thereof include diol, 2,4-dimethyl-2,4-pentanediol and the like.

Examples of the β-diketone compound used as the organic ligand of the other precursors described above include acetylacetone, hexane-2,4-dione, 5-methylhexane-2,4-dione, and 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- Alkyl-substituted β-diketones such as 3,5-dione, 2,2-dimethyl-6-ethyldecane-3,5-dione; 1,1,1-trifluoropentane-2,4-dione, 1,1, 1-Trifluoro-5,5-dimethylhexane-2,4-dione, 1,1,1,5,5,5-hexafluoropentane-2,4-dione, 1,3-diperfluorohexylpropane- Fluoro-substituted alkyl β-diketones such as 1,3-dione; 1,1,5,5-tetramethyl-1-methoxyhexane-2,4-dione, 2,2,6,6-tetramethyl-1- Examples thereof include ether-substituted β-diketones such as methoxyheptane-3,5-dione and 2,2,6,6-tetramethyl-1- (2-methoxyethoxy) heptane-3,5-dione.

Examples of the cyclopentadiene compound used as the organic ligand of the other precursors described above include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, isopropylcyclopentadiene, butylcyclopentadiene, and second butylcyclopentadiene. Examples thereof include isobutylcyclopentadiene, tert-butylcyclopentadiene, dimethylcyclopentadiene, tetramethylcyclopentadiene and the like.

Examples of the organic amine compound used as the organic ligand of the above other precursors include methylamine, ethylamine, propylamine, isopropylamine, butylamine, sec-butylamine, tert-butylamine, isobutylamine, dimethylamine, diethylamine and dipropyl. Examples thereof include amines, diisopropylamines, ethylmethylamines, propylmethylamines and isopropylmethylamines.

The other precursors described above are known in the art, and their manufacturing methods are also known. For example, when an alcohol compound is used as an organic ligand, a precursor can be produced by reacting the above-mentioned inorganic salt of a metal or a hydrate thereof with an alkali metal alkoxide of the alcohol compound. can. Here, examples of the inorganic salt of the metal or its hydrate include metal halides and nitrates, and examples of the alkali metal alkoxide include sodium alkoxide, lithium alkoxide, potassium alkoxide and the like. Can be done.

In the multi-component CVD method as described above, a method of vaporizing and supplying the raw material for thin film formation independently (hereinafter, also referred to as “single source method”) and a multi-component raw material are desired in advance. There is a method of vaporizing and supplying a mixed raw material mixed with the composition of (hereinafter, may be referred to as "cocktail sauce method"). In the case of the single source method, as the other precursor, a compound whose thermal and / or oxidative decomposition behavior is similar to that of the yttrium compound represented by the general formula (1) or (2) is preferable. In the case of the cocktail sauce method, as the other precursors described above, in addition to the behavior of thermal and / or oxidative decomposition being similar to that of the ittrium compound represented by the above general formula (1) or (2), at the time of mixing. A compound that does not deteriorate due to a chemical reaction or the like is preferable.

In the case of the cocktail sauce method in the multi-component CVD method, a mixture of the yttrium compound represented by the above general formula (1) or (2) and another precursor or a mixed solution obtained by dissolving the mixture in an organic solvent is made into a thin film. It can be used as a raw material for formation.

As the above-mentioned organic solvent, a well-known general organic solvent can be used without any particular limitation. Examples of the organic solvent include acetate esters such as ethyl acetate, butyl acetate and methoxyethyl acetate; ethers such as tetrahydrofuran, tetrahydropyran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, dibutyl ether and dioxane; methyl. Ketones such as butyl ketone, methylisobutylketone, ethylbutylketone, dipropylketone, diisobutylketone, methylamylketone, 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 and the like can be mentioned. These organic solvents may be used alone or in combination of two or more depending on the solubility of the solute, the relationship between the operating temperature and the boiling point, the flash point, and the like.

When the raw material for forming a thin film of the present invention is a mixed solution containing the above organic solvent, the total amount of the precursor in the raw material for forming a thin film is preferably 0.01 mol / liter to 2.0 mol / liter, more preferably. It may be adjusted to be 0.05 mol / liter to 1.0 mol / liter.

Here, the total amount of the precursor is represented by the above general formula (1) or (2) when the raw material for forming a thin film of the present invention does not contain a compound containing a metal other than yttrium and a compound containing a semi-metal. Represents the amount of the yttrium compound (however, when the raw material for forming a thin film of the present invention further contains another yttrium-containing precursor, the total amount of the precursor is represented by the above general formula (1) or (2). Represents the total amount of yttrium compound to be produced and other precursors containing yttrium). When the raw material for forming a thin film of the present invention contains another precursor in addition to the yttrium compound represented by the above general formula (1) or (2), it is represented by the above general formula (1) or (2). Represents the total amount of yttrium compound and other precursors.

Further, the raw material for forming a thin film of the present invention contains a nucleophile in order to improve the stability of the yttrium compound represented by the above general formula (1) or (2) and other precursors, if necessary. You may. Examples of the nucleophilic reagent include ethylene glycol ethers such as glyme, diglyme, triglime, and tetraglyme, 18-crown-6, dicyclohexyl-18-crown-6, 24-crown-8, and dicyclohexyl-24-crown. -8, Crown ethers such as dibenzo-24-crown-8, ethylenediamine, N, N'-tetramethylethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, 1,1,4,7, Polyamines such as 7-pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetramine, triethoxytriethyleneamine, cyclic polyamines such as cyclum and cyclone, pyridine, pyrrolidine, piperidine, morpholin. , N-Methylpyrrolidin, N-Methylpiperidine, N-methylmorpholine, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, oxazole, thiazole, oxathiolane and other heterocyclic compounds, methyl acetoacetate, ethyl acetoacetate, acetoacetate- Examples thereof include β-ketoesters such as 2-methoxyethyl or β-diketones such as acetylacetone, 2,4-hexanedione, 2,4-heptandione, 3,5-heptandione and dipivaloylmethane. The amount of these nucleophiles used is preferably in the range of 0.1 mol to 10 mol, more preferably in the range of 1 mol to 4 mol, with respect to 1 mol of the total amount of precursor.

It is desirable that the raw material for forming a thin film of the present invention contains as little as possible impurity metal elements other than the constituents thereof, impurity halogens such as impurity chlorine, and impurity organics. 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 a gate insulating film, a gate film, or a barrier layer of an LSI, it is necessary to reduce the contents of alkali metal elements and alkaline earth metal elements that affect the electrical characteristics of the obtained thin film. The impurity halogen content is preferably 100 ppm or less, more preferably 10 ppm or less, still more preferably 1 ppm or less. The total amount of the impurity organic content is preferably 500 ppm or less, more preferably 50 ppm or less, still more preferably 10 ppm or less. In addition, since water causes particles to be generated in the raw material for CVD and particles to be generated during thin film formation, precursors, organic solvents and nucleophiles are used to reduce the water content of each. It is better to remove as much water as possible in advance. The water content of each of the precursor, the organic solvent and the nucleophilic reagent is preferably 10 ppm or less, more preferably 1 ppm or less.

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

<Thin film manufacturing method>
Next, a method for producing a thin film of the present invention using the above-mentioned raw material for forming a thin film will be described.
Here, as one embodiment, a method for producing a thin film containing a yttrium atom (hereinafter, also referred to as “yttrium-containing thin film”) by the ALD method will be described.

A well-known ALD device can be used as the device used in the method for producing a thin film of the present invention. Specific examples of the device include a device capable of bubbling and supplying a precursor as shown in FIGS. 1 and 3, and a device having a vaporization chamber as shown in FIGS. 2 and 4. Further, as shown in FIGS. 3 and 4, an apparatus capable of performing plasma treatment on the reactive gas can be mentioned. In addition to the single-wafer type apparatus as shown in FIGS. 1 to 4, an apparatus capable of simultaneously processing a large number of sheets using a batch furnace can also be used. These devices can be used as CVD devices.

In the method for producing a thin film of the present invention, the raw material gas obtained by vaporizing the above-mentioned thin film forming raw material is introduced into a film forming chamber in which a substrate is installed (hereinafter, may be referred to as a "deposition reaction portion"). A step (raw material gas introduction step), a step of depositing the yttrium compound in the raw material gas on the surface of the substrate to form a precursor thin film (precursor thin film forming step), and a step of depositing a reactive gas in the film forming chamber. It has a step of forming an ittrium-containing thin film on the surface of the substrate (ittrium-containing thin film forming step) by introducing the precursor thin film and reacting the reactive gas with the reaction gas. Further, the method for producing a thin film of the present invention is a step of exhausting gas in the film forming chamber between the precursor thin film forming step and the ittrium-containing thin film forming step and / or after the ittrium-containing thin film forming step (exhaust step). It is preferable to have.

As an embodiment of the method for producing a thin film of the present invention, a series of operations of forming a precursor thin film, an exhaust step, an yttrium-containing thin film forming step, and an exhaust step are performed in order, and the deposition is set as one cycle, and this cycle is repeated. , The thickness of the thin film of the present invention can be adjusted. Hereinafter, each step of the thin film manufacturing method of the present invention will be described.

(Raw material gas introduction process)
The raw material gas introduction step is a step of vaporizing the above-mentioned raw material for forming a thin film into a raw material gas, and introducing the raw material gas into a deposition reaction section in which a substrate is installed.
As a method for transporting and supplying the raw material for thin film formation, as shown in FIGS. 1 and 3, heating is performed in a container (hereinafter, also referred to as “raw material container”) in which the raw material for thin film formation of the present invention is stored. And / or a gas transport method in which the raw material gas is vaporized by depressurizing to obtain a raw material gas, and if necessary, the raw material gas is introduced into the deposition reaction section where the substrate is installed together with carrier gas such as argon, nitrogen, and helium. As shown in FIGS. 2 and 4, the raw material for forming a thin film is transported to a vaporization chamber in the form of a liquid or a solution, and vaporized by heating and / or depressurizing in the vaporization chamber to obtain a raw material gas, and the raw material gas is used as a substrate. There is a liquid transport method to introduce into the deposition reaction part where is installed. In the case of the gas transport method, the yttrium compound itself represented by the above general formula (1) or (2) can be used as a raw material for forming a thin film. In the case of the liquid transport method, the yttrium compound represented by the above general formula (1) or (2) or a solution obtained by dissolving the yttrium compound in an organic solvent can be used as a raw material for forming a thin film. These raw materials for forming a thin film may further contain a nucleophilic reagent or the like.

In addition to the above gas transport method and liquid transport method, as a method used in the raw material gas introduction step, a multi-component ALD method including a plurality of precursors is used as a single as described in <Thin film forming raw material>. There are a sauce method and a cocktail sauce method, and regardless of which introduction method is used, it is preferable that the raw material for forming a thin film of the present invention is vaporized in the range of 0 ° C to 200 ° C. Further, when the raw material for forming a thin film is vaporized into a raw material gas in the raw material container or in the vaporization chamber, the pressure in the raw material container and the pressure in the vaporization chamber are preferably in the range of 1 Pa to 10,000 Pa.

Here, examples of the material of the substrate installed in the deposition reaction section include silicon; ceramics such as silicon nitride, titanium nitride, tantalum nitride, titanium oxide, ruthenium oxide, zirconium oxide, hafnium oxide, and lanthanum oxide; glass; Examples thereof include metals such as metallic cobalt and metallic ruthenium. Examples of the shape of the substrate include plate-like, spherical, fibrous, and scaly shapes. The surface of the substrate may be flat or may have a three-dimensional structure such as a trench structure.

(Precursor thin film forming step)
In the precursor thin film forming step, the yttrium compound represented by the above general formula (1) or (2) in the raw material gas introduced into the deposition reaction section in which the substrate is installed is deposited on the surface of the substrate to deposit the substrate. A precursor thin film is formed on the surface. At this time, the substrate may be heated, or the deposition reaction portion may be heated to apply heat. The production conditions for forming the precursor thin film are not particularly limited, and for example, the reaction temperature (base temperature), reaction pressure, deposition rate and the like can be appropriately determined according to the type of the thin film forming raw material. The reaction temperature is preferably 100 ° C. or higher, which is a temperature at which the raw material for forming a thin film of the present invention sufficiently reacts, and more preferably 100 ° C. to 400 ° C. The reaction pressure is preferably 1 Pa to 10,000 Pa, more preferably 10 Pa to 1,000 Pa.

Further, the deposition rate can be controlled by the supply conditions (vaporization temperature, vaporization pressure), reaction temperature, and reaction pressure of the raw material for thin film formation. If the deposition rate is high, the characteristics of the obtained thin film may deteriorate, and if it is low, productivity problems may occur. Therefore, 0.01 nm / min to 100 nm / min is preferable, and 0.1 nm / min to 50 nm / min is preferable. Minutes are more preferred.

(Exhaust process)
After forming the precursor thin film, the raw material gas that has not accumulated on the surface of the substrate is exhausted from the deposition reaction section. At this time, it is ideal that the raw material gas is completely exhausted from the deposition reaction portion, but it is not always necessary to completely exhaust the raw material gas. Examples of the exhaust method include a method of purging the inside of the system of the deposition reaction part with an inert gas such as helium, nitrogen, and argon, a method of exhausting by depressurizing the inside of the system, and a method of combining these. The degree of decompression in the case of depressurization is preferably in the range of 0.01 Pa to 300 Pa, more preferably in the range of 0.01 Pa to 100 Pa.

(Yttrium-containing thin film forming process)
In the yttrium-containing thin film forming step, after the exhaust step, a reactive gas is introduced into the deposition reaction section and deposited on the surface of the precursor thin film, that is, the substrate by the action of the reactive gas or the action of the reactive gas and the action of heat. The yttrium compound represented by the above general formula (1) or (2) is reacted with the reactive gas to form an yttrium-containing thin film.

Examples of the reactive gas include oxidizing gas such as oxygen, ozone, nitrogen dioxide, nitrogen monoxide, steam, hydrogen peroxide, formic acid, acetic acid and anhydrous acetic acid, reducing gas such as hydrogen, monoalkylamine and dialkyl. Examples thereof include organic amine compounds such as amines, trialkylamines and alkylenediamines, and nitrided gases such as hydrazine and ammonia. These reactive gases may be used alone or in combination of two or more. In the method for producing a thin film of the present invention, the reactive gas is preferably an oxidizing gas, and more preferably a gas containing oxygen, ozone or water vapor. When an oxidizing gas is used as the reactive gas, a yttrium oxide thin film is formed as the yttrium-containing thin film.

When heat is used in the reaction between the precursor thin film and the reactive gas, the reaction is preferably in the range of 50 ° C to 500 ° C, and more preferably in the range of 100 ° C to 400 ° C. The pressure in the deposition reaction section when this step is performed is preferably 1 Pa to 10,000 Pa, more preferably 10 Pa to 1,000 Pa.

(Exhaust process)
After forming the yttrium-containing thin film, unreacted reactive gas and by-product gas are exhausted from the deposition reaction section. At this time, it is ideal that the reactive gas and the by-product gas are completely exhausted from the deposition reaction portion, but it is not always necessary to completely exhaust the reactive gas and the by-product gas. The exhaust method and the degree of decompression in the case of depressurization are the same as those in the exhaust step after the precursor thin film forming step described above.

As described above, the raw material gas introduction step, the precursor thin film forming step, the exhaust process, the yttrium-containing thin film forming step and the exhaust step are carried out in order, and the deposition by a series of operations is regarded as one cycle, and this cycle is the required film thickness. By repeating this process a plurality of times until a thin film is obtained, an yttrium-containing thin film having a desired film thickness is produced. In the method for producing a thin film using the ALD method, the film thickness of the yttrium-containing thin film to be formed can be controlled by the number of cycles.

Further, in the method for producing a thin film of the present invention, as shown in FIGS. 3 and 4, energy such as plasma, light, and voltage may be applied to the deposition reaction portion, or a catalyst may be used. The timing of applying the energy and the timing of using the catalyst are not particularly limited, and for example, the reaction in the raw material gas introduction step, the heating in the precursor thin film forming step, and the reaction in the yttrium-containing thin film forming step. It may be at the time of introducing the sex gas, at the time of reacting the reactive gas with the precursor thin film, at the time of exhausting in the system in the exhausting step, or during each of the above steps.

Further, in the method for producing a thin film of the present invention, after the thin film is formed, annealing treatment may be performed in an inert atmosphere, an oxidizing atmosphere or a reducing atmosphere in order to obtain better electrical characteristics. If embedding is required, a reflow process may be provided. In this case, the temperature is preferably 200 ° C to 1,000 ° C, more preferably 250 ° C to 500 ° C.

The thin film produced by using the raw material for forming a thin film of the present invention covers a substrate such as metal, oxide ceramics, nitride ceramics, and glass by appropriately selecting other precursors, reactive gases, and production conditions. Therefore, a desired type of thin film can be obtained. Since the thin film of the present invention is excellent in electrical characteristics and optical characteristics, for example, it is used for electrode materials of memory elements represented by DRAM elements, resistance films, antimagnetic films used for recording layers of hard disks, and polymer electrolyte fuel cells. It can be widely used in the production of catalyst materials and the like.

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

[Production Example 1] Yttrium compound No. Production of No. 1 To a 100 mL three-necked flask, 1.78 g (3.12 mmol) of yttrium-tris-trimethylsilylamide and 5.8 g of dehydrated toluene were added and mixed thoroughly. 2.02 g (10.92 mmol) of 5-((2-methoxyethyl) amino) -4-heptene-3-one was added dropwise to this suspension at room temperature. After stirring at 85 ° C. for 3 hours, the solvent was removed in an oil bath at 130 ° C. under reduced pressure. The generated yttrium complex (orange viscous liquid) was placed in a flask, connected to a Kugelrohr purification device, and distilled at a heating temperature of 230 ° C. and 55 Pa to obtain a yellow viscous liquid. The obtained yellow viscous liquid was ^{analyzed by 1} H-NMR and ICP-AES, and as a result, yttrium compound No. It was confirmed that it was 1. The analysis results of the obtained yellow viscous liquid are shown below.

(1) ^{1 1} H-NMR (heavy benzene)
0.993-1.031ppm (9H, triplet), 1.204-1.242ppm (9H, triplet), 2.118-2.754ppm (6H, quartet), 2.183-2.240ppm (6H, quartet) ), 3.223 ppm (9H, singlet), 3.477-3.501 ppm (6H, triplet), 3.690-3.721 ppm (6H, triplet), 4.953 ppm (3H, singlet).

(2) Element analysis result by ICP-AES Y: 13.9% by mass (theoretical value: 13.66% by mass), C: 55.4% by mass (theoretical value: 55.37% by mass), H: 9. 8% by mass (theoretical value: 9.75% by mass), N: 6.4% by mass (theoretical value: 6.46% by mass), O: 14.5% by mass (theoretical value: 14.76% by mass)

[Production Example 2] Yttrium compound No. Production of 3 To a 100 mL three-necked flask, 1.57 g (2.76 mmol) of yttrium-tris-trimethylsilylamide and 5.1 g of dehydrated toluene were added and mixed thoroughly. To this suspension, 2.06 g (9.66 mmol) of 5-((2-methoxyethyl) amino) -2,6-dimethyl-4-heptene-3-one was added dropwise at room temperature. After stirring at 55 ° C. for 5 hours, the solvent was removed in an oil bath at 111 ° C. under reduced pressure. The produced yttrium complex (orange viscous liquid) was placed in a flask, connected to a Kugelrohr purifier, and distilled at a heating temperature of 205 ° C. and 21 Pa to obtain a yellow viscous liquid. The obtained yellow viscous liquid became a yellow solid when allowed to cool to room temperature. The obtained yellow viscous liquid was ^{analyzed by 1} H-NMR and ICP-AES, and as a result, yttrium compound No. It was confirmed that it was 3. The analysis results of the obtained yellow viscous liquid are shown below.

(1) ^{1 1} H-NMR (heavy benzene)
1.061-1.077ppm (18H, doublet), 1.228-1.244ppm (18H, doublet), 2.403-2.505ppm (3H, septet), 2.967-3.064ppm (3H, septet) ), 3.213 ppm (9H, singlet), 3.430-3.462 ppm (6H, triplet), 3.802-3.834 ppm (6H, triplet), 5.112 ppm (3H, singlet).

(2) Element analysis result by ICP-AES Y: 12.3% by mass (theoretical value: 12.09% by mass), C: 58.4% by mass (theoretical value: 58.84% by mass), H: 10. 3% by mass (theoretical value: 10.29% by mass), N: 5.9% by mass (theoretical value: 5.71% by mass), O: 13.1% by mass (theoretical value: 13.07% by mass)

[Production Example 3] Yttrium compound No. Preparation of No. 6 To a 100 mL three-necked flask, 1.41 g (2.47 mmol) of yttrium-tris-trimethylsilylamide and 6.8 g of dehydrated toluene were added and mixed well. 2.08 g (8.65 mmol) of 2,2,6-trimethyl-5-((1-methoxy-2-propyl) amino) -4-heptene-3-one was added dropwise to this suspension at room temperature. After stirring at 53 ° C. for 4 hours, the solvent was removed in an oil bath at 115 ° C. under reduced pressure. The produced yttrium complex (orange viscous substance) was placed in a flask, connected to a Kugelrohr purifier, and distilled at a heating temperature of 214 ° C. and 17 Pa to obtain a yellow liquid. The obtained yellow liquid became a yellow glassy solid when allowed to cool to room temperature. As a result of elemental analysis by ICP emission spectroscopy, yttrium compound No. It was confirmed that it was 6.

(1) Element analysis result by ICP-AES Y: 10.85% by mass (theoretical value: 10.85% by mass), C: 61.7% by mass (theoretical value: 61.58% by mass), H: 10. 5% by mass (theoretical value: 10.71% by mass), N: 5.2% by mass (theoretical value: 5.14% by mass), O: 11.8% by mass (theoretical value: 11.72% by mass)

[Production Example 4] Yttrium compound No. Production of 15 To a 100 mL three-necked flask, 1.65 g (2.90 mmol) of yttrium-tris-trimethylsilylamide and 8.0 g of dehydrated toluene were added and mixed well. 2.02 g (10.2 mmol) of 5-amino-1-methoxy-2,2,6-trimethyl-4-heptene-3-one was added dropwise to this suspension at room temperature. After stirring at 86 ° C. for 5 hours, the solvent was removed in an oil bath at 120 ° C. under reduced pressure. The produced yttrium complex (reddish brown viscous substance) was placed in a flask, connected to a Kugelrohr purifier, and distilled at a heating temperature of 210 ° C. and 23 Pa to obtain a yellow liquid. The obtained yellow liquid was allowed to cool to room temperature to obtain a yellow solid. The obtained yellow solid was ^{analyzed by 1} H-NMR and ICP-AES, and as a result, yttrium compound No. It was confirmed that it was 15. The analysis results of the obtained yellow solid are shown below.

(1) ^{1 1} H-NMR (heavy benzene)
0.908ppm (18H, broad), 1.393ppm (18H, singlet), 2.079ppm (3H, singlet), 3.239ppm (9H, singlet), 3.525ppm (6H, singlet), 5.269ppm (3H) , Singlet), 7.378ppm (3H, broad)

(2) Element analysis result by ICP-AES Y: 12.8% by mass (theoretical value: 12.83% by mass), C: 57.5% by mass (theoretical value: 57.21% by mass), H: 10. 0% by mass (theoretical value: 10.03% by mass), N: 6.1% by mass (theoretical value: 6.07% by mass), O: 13.6% by mass (theoretical value: 13.86% by mass)

[Production Example 5] Production of Comparative Compound 1 To a 100 mL three-necked flask, 2.44 g (4.28 mmol) of yttrium-tris-trimethylsilylamide and 7.9 g of dehydrated toluene were added and mixed thoroughly. 1.91 g (15.0 mmol) of 5-amino-4-heptene-3-one was added dropwise to this suspension at room temperature. After stirring at 87 ° C. for 3 hours, the solvent was removed in an oil bath at 111 ° C. under reduced pressure. The generated yttrium complex (orange viscous liquid) was placed in a flask, connected to a Kugelrohr purifier, and distilled at a heating temperature of 215 ° C. and 50 Pa to obtain a yellow viscous liquid. The obtained yellow viscous liquid was allowed to cool to room temperature to obtain a yellow solid. ^{As a result of analysis by 1} H-NMR and ICP-AES, it was confirmed that the obtained yellow solid was Comparative Compound 1 shown below. The analysis results of the obtained yellow solid are shown below.

(1) ^{1 1} H-NMR (heavy benzene)
0.879-0.916ppm (9H, triplet), 1.232-1.270ppm (9H, triplet), 1.919-1.976ppm (6H, quartet), 2.306-2.363ppm (6H, quartet) ), 5.025-5.030ppm (3H, doublet), 7.614ppm (3H, singlet)

(2) Element analysis results by ICP-AES Y: 18.9% by mass (theoretical value: 18.66% by mass), C: 52.8% by mass (theoretical value: 52.93% by mass), H: 9. 4% by mass (theoretical value: 9.51% by mass), N: 8.7% by mass (theoretical value: 8.82% by mass), O: 10.2% by mass (theoretical value: 10.08% by mass)

Yttrium compound No. 1 produced in Production Examples 1 to 5 above. 1, No. 3, No. 6, No. The following evaluation was performed using 15 and Comparative Compound 1.

(1) Melting point evaluation Visually observe the state of the compound at normal pressure of 25 ° C, and for solid compounds, use a differential scanning calorimeter DSC to raise the temperature at 10 ° C / min and set the scanning temperature range to 30 ° C to 600. In the obtained chart measured as ° C, the temperature of the intersection of the straight line extending the baseline on the low temperature side to the high temperature side and the tangent line drawn at the point where the gradient becomes maximum on the curve on the low temperature side of the peak showing the heat absorption reaction. Was evaluated as the melting point. The results are shown in Table 1.

(2) Temperature (° C.) when reduced pressure TG-DTA 50% by mass
Using TG-DTA, the temperature was measured with 10 Torr, an argon flow rate of 50 mL / min, a heating rate of 10 ° C./min, and a scanning temperature range of 30 ° C. to 600 ° C., and the temperature when the mass of the test compound was reduced by 50% by mass ( ° C.) was evaluated as "temperature (° C.) when reduced pressure TG-DTA 50% by mass". It is shown that the lower the temperature (° C.) when the reduced pressure TG-DTA is reduced by 50% by mass, the lower the temperature, the lower the temperature, the more steam can be obtained. The results are shown in Table 1.

(3) Thermal decomposition start temperature (° C)
In the DSC chart measured with a differential scanning calorimeter DSC at a heating rate of 10 ° C./min and a scanning temperature range of 30 ° C. to 600 ° C., the start point of heat generation or endothermic evaluation was evaluated as the thermal decomposition start temperature (° C.). .. The results are shown in Table 1.

From Table 1, the comparative compound 1 had a thermal decomposition start temperature of 267 ° C., was poor in thermal stability, and was not satisfactory as a raw material for forming a thin film.

On the other hand, yttrium compound No. 1, No. 3, No. 6 and No. It was confirmed that No. 15 had an excellent thermal stability because the thermal decomposition start temperature was 300 ° C. or higher even though the melting point was low. Further, it was confirmed that the temperature of these yttrium compounds when the reduced pressure TG-DTA was reduced by 50% by mass was around 230 ° C., and vapor could be obtained at a low temperature. From these results, it was confirmed that the yttrium compound represented by the general formula (1) or (2) is useful as a raw material for forming a thin film. In addition, compound No. of Example 3 The appearance of No. 6 was similar to that of water glass and had no fluidity.

[Example 5] Production of thin film by ALD method Yttrium compound No. A thin film was produced on silicon dioxide as a substrate under the following conditions using 15 as a raw material for forming a thin film and using the ALD apparatus of FIG. When the composition of the thin film was analyzed using X-ray photoelectron spectroscopy, it was confirmed that the thin film was a thin film containing yttrium oxide and the residual carbon content was less than the detection limit of 0.01 atom%. Further, when the film thickness of the thin film was measured by the X-ray reflectivity method, the thin film formed on the substrate was a smooth film with a film thickness of 20 nm, and the film thickness obtained per cycle was about 0. It was 0.05 nm.

(conditions)
Manufacturing method: ALD method Reaction temperature (base temperature): 300 ° C
Reactive gas: ozone (process)
A series of steps consisting of the following (1) to (4) was regarded as one cycle, and 400 cycles were repeated.
(1) The raw material gas obtained by vaporizing the raw material for thin film formation under the conditions of the raw material container temperature of 200 ° C. and the pressure inside the raw material container of 100 Pa is introduced into the film forming chamber, and the raw material gas is placed on the surface of the substrate at a system pressure of 100 Pa for 10 seconds. The yttrium compound inside is deposited to form a precursor thin film.
(2) The raw material gas that has not accumulated is exhausted from the system by argon purging for 15 seconds.
(3) The reactive gas is introduced into the film forming chamber, and the precursor thin film and the reactive gas are reacted at a system pressure of 100 Pa for 10 seconds.
(4) Unreacted reactive gas and by-product gas are exhausted from the system by argon purging for 15 seconds.

[Example 6] Production of thin film by ALD method Yttrium compound No. 3 was used as a raw material for forming a thin film, and a thin film was produced on silicon dioxide as a substrate under the following conditions using the ALD apparatus of FIG. When the composition of the thin film was analyzed using X-ray photoelectron spectroscopy, it was confirmed that the thin film was a thin film containing yttrium oxide and the residual carbon content was less than the detection limit of 0.01 atom%. Further, when the film thickness of the thin film was measured by the X-ray reflectivity method, the thin film formed on the substrate was a smooth film with a film thickness of 16 nm, and the film thickness obtained per cycle was about 0. It was .04 nm.

[Comparative Example 2] Production of Thin Film by ALD Method A thin film was produced on silicon dioxide as a substrate under the same conditions as in Example 5 except that Comparative Compound 1 was used as a raw material for forming a thin film. When the composition of the thin film was analyzed using X-ray electron spectroscopy, the thin film was a thin film containing yttrium oxide, but residual carbon was detected. Moreover, when the state of the thin film was observed using the scanning electron microscope method, the thin film formed on the substrate was not smooth and the film thickness could not be measured.

From the above, the raw material for forming a thin film containing the yttrium compound of the present invention has a low melting point, vapor can be obtained at a low temperature, and the thermal stability is excellent. Therefore, when a thin film is produced using the raw material for forming a thin film of the present invention, a high-quality yttrium-containing thin film having a small amount of residual carbon can be produced.

Claims

A raw material for forming a thin film containing an yttrium compound represented by the following general formula (1) or (2).

(In the formula, R 1 and R 3 independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 6 carbon atoms, and R 2 is a hydrogen atom or 1 carbon atom. R 4 represents an alkyl group having 1 to 3 carbon atoms, R 4 represents an alkyl group having 1 to 5 carbon atoms, R 5 represents an alkyl group having 1 to 3 carbon atoms, and a plurality of R 1 , R 2 , and R. 3 , R 4 and R 5 may be the same or different from each other.)

(In the formula, R 6 and R 8 independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 6 carbon atoms, and R 7 is a hydrogen atom or 1 carbon atom. Representing an alkyl group of ~ 3, the plurality of R 6 , R 7 and R 8 may be the same or different, respectively, except that at least one of R 6 and R 8 is carbon. Represents an alkoxyalkyl group having 2 to 6 atoms.)
In the general formula (1) , an yttrium compound in which R 1 and R 3 are isopropyl groups, R 2 is a hydrogen atom, R 4 is an ethylene group, and R 5 is a methyl group, or the general formula (1). The raw material for forming a thin film according to claim 1, which contains an yttrium compound in which R 6 is a methoxytert-butyl group, R 7 is a hydrogen atom, and R 8 is an isopropyl group in 2).
A thin film made by using the raw material for forming a thin film according to claim 1 or 2.
A step of introducing the raw material gas obtained by vaporizing the raw material for forming a thin film according to claim 1 or 2 into a film forming chamber in which a substrate is installed, and a step of introducing the raw material gas.
A step of depositing the yttrium compound in the raw material gas on the surface of the substrate to form a precursor thin film, and
A method for producing a thin film, which comprises a step of introducing a reactive gas into the film forming chamber and reacting the precursor thin film with the reactive gas to form a thin film containing an yttrium atom on the surface of the substrate. ..
The method for producing a thin film according to claim 4, wherein the reactive gas is an oxidizing gas and the thin film containing the yttrium atom is yttrium oxide.
The method for producing a thin film according to claim 5, wherein the oxidizing gas is a gas containing oxygen, ozone, or water vapor.
The method for producing a thin film according to any one of claims 4 to 6, wherein the precursor thin film and the reactive gas are reacted in the range of 100 ° C to 400 ° C.