Raw material for forming thin film, thin film, method for producing thin film, and lanthanum compound

Abstract

There is provided a raw material for forming a thin film containing a lanthanum compound represented by general formula (1).　[Formula 1] (In general formula (1), R1, R3, R4, R6, R7, and R9 each independently represent a C1-8 aliphatic hydrocarbon or a C1-8 hetero atom-containing hydrocarbon group, and R2, R5, and R8 each independently represent a hydrogen atom or a C1-3 alkyl group.　However, lanthanum compounds in which R1 and R3, R4 and R6, and R 7 and R9 are all the same groups as each other, and all of R 2, R5, and R8 are the same groups, are excluded).

Description

Thin film forming material, thin film, method for producing thin film, and lanthanum compound

[0001] The present disclosure relates to a thin film-forming material containing a lanthanum compound having a specific structure, a thin film produced using the thin film-forming material, a method for producing a thin film, and the lanthanum compound.

[0002] Thin film forming raw materials containing lanthanum atoms are used as materials for manufacturing DRAM gates, Logic transistors, and the like.

[0003] Methods for producing a thin film containing lanthanum atoms (hereinafter sometimes referred to as a "lanthanum-containing thin film") include sputtering, ion plating, metal organic decomposition (MOD) methods such as coating pyrolysis and sol-gel methods, and chemical vapor deposition. Among these, chemical vapor deposition methods including chemical vapor deposition (hereinafter sometimes referred to as a "CVD (Chemical Vapor Deposition) method") and atomic layer deposition (hereinafter sometimes referred to as an "ALD (Atomic Layer Deposition) method") are the most suitable production processes because they have many advantages such as excellent composition controllability and step coverage, suitability for mass production, and the ability to achieve hybrid integration.

[0004] Various lanthanum compounds are known as raw materials for forming lanthanum-containing thin films. For example, Patent Document 1 discloses a lanthanoid complex in which an amidinate ligand and a cyclopentadienyl group are coordinated, Patent Document 2 discloses a lanthanum compound in which a ketoimine ligand and an alkoxy group are coordinated, and Patent Documents 3 to 5 disclose lanthanum amidinate compounds.

[0005] International Publication No. 2022 / 106508 Japanese Patent Publication No. 2012-153688 Chinese Patent Application Publication No. 114192136 US Patent Application Publication No. 2013 / 0078454 Chinese Patent Application Publication No. 113582879

[0006] However, when a thin film is produced using the compounds described in Patent Documents 1 and 2, it is difficult to obtain a high-quality lanthanum atom-containing thin film with little residual carbon. The compounds described in Patent Documents 3 to 5 have a high melting point, which causes a problem of clogging in the piping of a thin film production apparatus.

[0007] Therefore, an object of the present disclosure is to provide a thin film-forming raw material capable of forming a high-quality lanthanum-containing thin film that has a low melting point and little residual carbon, and a method for producing a thin film using the same.

[0008] As a result of intensive research into solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a thin film-forming raw material containing a lanthanum compound having a specific structure, and have thus completed the present disclosure.

[0009] That is, the present disclosure provides a thin film-forming material containing a lanthanum compound represented by the following general formula (1):

[0010]

[0011] In general formula (1), R 1 , R 3 , R 4 , R 6 , R 7 and R 9 each independently represents an aliphatic hydrocarbon group having from 1 to 8 carbon atoms or a heteroatom-containing hydrocarbon group having from 1 to 8 carbon atoms; R 2 , R 5 and R 8 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 1 and R 3 And, R 4 and R 6 And, R 7 and R 9 and are all the same group, and R 2 , R 5 and R 8 Excluding lanthanum compounds in which all are the same group.

[0012] The present disclosure provides a thin film produced using the above-described thin film-forming raw material.

[0013] The present disclosure provides a method for producing a thin film, which includes forming a thin film containing lanthanum atoms using the above-described thin film-forming raw material.

[0014] The present disclosure provides a lanthanum compound represented by the following general formula (2):

[0015]

[0016] In general formula (2), R 10 represents an aliphatic hydrocarbon group having from 4 to 8 carbon atoms or a heteroatom-containing hydrocarbon group having from 4 to 8 carbon atoms; R 12 , R 13 and R 15 each independently represents an aliphatic hydrocarbon group having from 1 to 4 carbon atoms or a heteroatom-containing hydrocarbon group having from 1 to 4 carbon atoms; R 11 and R 14 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X represents 1 or 2. 10 and R 12 And, R 13 and R 15 and are the same group, and R 11 and R 14 Excluding lanthanum compounds in which

[0017] The lanthanum compound represented by the following general formula (3) has the same meaning as the lanthanum compound represented by the above general formula (1).

[0018]

[0019] R in the above general formula (3) 1 ~R 9 represents R in general formula (1). 1 ~R 9 represents the same group as

[0020] According to the present disclosure, it is possible to provide a thin film-forming material capable of forming a lanthanum-containing thin film having a low melting point and little residual carbon, and a method for producing a thin film using the same.

[0021] Fig. 1 is a schematic diagram showing an example of an ALD apparatus used in a method for producing a thin film according to an embodiment of the present disclosure. Fig. 2 is a schematic diagram showing another example of an ALD apparatus used in a method for producing a thin film according to an embodiment of the present disclosure. Fig. 3 is a schematic diagram showing another example of an ALD apparatus used in a method for producing a thin film according to an embodiment of the present disclosure. Fig. 4 is a schematic diagram showing another example of an ALD apparatus used in a method for producing a thin film according to an embodiment of the present disclosure.

[0022] A. Thin Film-Forming Raw Material The thin film-forming raw material of the present disclosure will be described.

[0023] A1. Lanthanum Compound Represented by General Formula (1) The thin film-forming material of the present disclosure may contain at least one lanthanum compound represented by the following general formula (1), and may contain two or more lanthanum compounds:

[0024]

[0025] In general formula (1), R 1 , R 3 , R 4 , R 6 , R 7 and R 9 each independently represents an aliphatic hydrocarbon group having from 1 to 8 carbon atoms or a heteroatom-containing hydrocarbon group having from 1 to 8 carbon atoms; R 2 , R 5 and R 8 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 1 and R 3 And, R 4 and R 6 And, R 7 and R 9 and are all the same group, and R 2 , R 5 and R 8 Excluding lanthanum compounds in which all are the same group.

[0026] In this specification, the term "mutually identical groups" means that two groups bonded to a nitrogen atom of an amidinate ligand are mutually identical to two groups bonded to a nitrogen atom of another amidinate ligand, and the term "all mutually identical groups" means that when there are three combinations of the above two groups, all of them are mutually identical. For example, R 1 and R 3 are different groups, R 1 and R 3 and R 4 and R 6 and are the same group, R 1 is R 4 or R 6 is the same group as either one of 3 is R 4 or R 6 represents the same group as the other group. 1 and R 3 are the same group, R 1 and R 3 and R 4 and R 6 and are the same group, R 1 , R 3 , R 4 and R 6 are all the same group. 1 and R 3 are different groups, R 1 and R 3 And, R 4 and R 6 And, R 7 and R 9 and are all the same group, R 1 is R 4 or R 6 is the same group as either one of 3 is R 4 or R 6 is the same group as the other group, and R 1 is R 7 or R 9 is the same group as either one of 3 is R 7 or R 9 represents the same group as the other group. 1 and R3 are the same group, R 1 and R 3 And, R 4 and R 6 And, R 7 and R 9 and are all the same group, R 1 , R 3 , R 4 , R 6 , R 7 and R 9 represents that all are the same group.

[0027] In general formula (1), R 1 , R 3 , R 4 , R 6 , R 7 and R 9 Examples of the aliphatic hydrocarbon group having 1 to 8 carbon atoms include saturated hydrocarbon groups having 1 to 8 carbon atoms, unsaturated hydrocarbon groups having 2 to 8 carbon atoms, and alicyclic hydrocarbon groups having 3 to 8 carbon atoms.

[0028] The saturated hydrocarbon group is an aliphatic hydrocarbon group that does not have a cyclic structure and does not have an unsaturated bond (double bond or triple bond) between carbon atoms, and may be linear or branched. Examples of the saturated hydrocarbon group include alkyl groups.

[0029] Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a 1-methylbutyl group, a 1-ethylpropyl group, a tert-pentyl group (a 1,1-dimethylpropyl group), a hexyl group, a heptyl group, a 2-heptyl group, a 3-heptyl group, an octyl group, and a 2-ethylhexyl group.

[0030] The unsaturated hydrocarbon group does not have a cyclic structure and represents an aliphatic hydrocarbon group having an unsaturated bond between some carbon atoms, such as a vinyl group, an allyl group, a butenyl group, a pentenyl group, and a hexenyl group.

[0031] The alicyclic hydrocarbon group represents an aliphatic hydrocarbon group having a cyclic structure, and may or may not have an unsaturated bond between carbon atoms. Examples of the alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group; cycloalkenyl groups such as a cyclopentenyl group and a cyclohexenyl group; cycloalkylalkyl groups in which some hydrogen atoms of the above-mentioned alkyl groups are substituted with cycloalkyl groups; and cycloalkenylalkyl groups in which some hydrogen atoms of the above-mentioned alkyl groups are substituted with cycloalkenyl groups.

[0032] In addition, in the general formula (1), R 1 , R 3 , R 4 , R 6 , R 7 and R 9 Examples of the heteroatom-containing hydrocarbon group having 1 to 8 carbon atoms represented by the formula (I) include the aliphatic hydrocarbon group in which at least one hydrogen atom has been substituted with a halogen atom or an amino group, the aliphatic hydrocarbon group in which some methylene groups have been substituted with oxygen atoms, or both.

[0033] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and examples of the aliphatic hydrocarbon group substituted with a halogen atom, when the halogen atom is a fluorine atom, include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, a pentafluoroethyl group, a fluoropropyl group, a heptafluoropropyl group, a fluoropentyl group, an undecylfluoropentyl group, etc. Furthermore, the aliphatic hydrocarbon group may be a group in which the fluorine atom is substituted with another halogen atom.

[0034] Examples of the amino group include a dimethylamino group, an ethylmethylamino group, and a diethylamino group. Examples of the aliphatic hydrocarbon group substituted with an amino group include a dimethylaminomethyl group, an ethylmethylaminomethyl group, a diethylaminomethyl group, a dimethylaminoethyl group, an ethylmethylaminoethyl group, a diethylaminoethyl group, a dimethylaminopropyl group, a 1-dimethylamino-2-propyl group, an ethylmethylaminopropyl group, a 1-ethylmethylamino-2-propyl group, a diethylaminopropyl group, and a 1-diethylamino-2-propyl group.

[0035] Examples of the aliphatic hydrocarbon group in which some methylene groups have been substituted with oxygen atoms include groups in which some hydrogen atoms of an alkyl group have been substituted with alkoxy groups, and specific examples include alkoxyalkyl groups such as a methoxymethyl group, a methoxyethyl group, a methoxypropyl group, a methoxybutyl group, a 1-methoxy-2-butyl group, an ethoxymethyl group, an ethoxyethyl group, an ethoxypropyl group, an ethoxybutyl group, and a 1-ethoxy-2-butyl group.

[0036] In the present disclosure, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film having a low melting point and little residual carbon, R 1 , R 3 , R 4 , R 6 , R 7 and R 9 At least one of R is preferably an aliphatic hydrocarbon group having 4 to 8 carbon atoms, more preferably a branched aliphatic hydrocarbon group having 4 to 8 carbon atoms, and even more preferably a branched alkyl group having 4 to 8 carbon atoms; 1 , R 3 , R 4 , R 6 , R 7 and R 9 It is particularly preferred that one or two of the groups be a branched alkyl group having 4 to 8 carbon atoms.

[0037] In the present disclosure, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film having a low melting point and little residual carbon, R1 , R 3 , R 4 , R 6 , R 7 and R 9 Preferably, two or more of R are aliphatic hydrocarbon groups having 1 to 3 carbon atoms. 1 , R 3 , R 4 , R 6 , R 7 and R 9 It is more preferable that two or more and five or less of R are aliphatic hydrocarbon groups having from 1 to 3 carbon atoms. 1 , R 3 , R 4 , R 6 , R 7 and R 9 It is more preferable that 3 to 5 of R are aliphatic hydrocarbon groups having 1 to 3 carbon atoms. 1 , R 3 , R 4 , R 6 , R 7 and R 9 It is most preferable that four or five of the groups be aliphatic hydrocarbon groups having 1 to 3 carbon atoms.

[0038] In the present disclosure, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film having a low melting point and little residual carbon, R 2 , R 5 and R 8 Preferably, at least one of R is a hydrogen atom, 2 , R 5 and R 8 More preferably, two or more of R 2 , R 5 and R 8 It is more preferable that all of are hydrogen atoms.

[0039] In addition, in the present disclosure, from the viewpoint that it is easy to form a high-quality lanthanum-containing thin film having a low melting point and little residual carbon, R 1 , R 3 , R 4 , R 6 , R 7 and R9 At least one of the groups is preferably a heteroatom-containing hydrocarbon group having from 1 to 8 carbon atoms, more preferably a heteroatom-containing hydrocarbon group having an alkoxyalkyl group or a dialkylamino group, still more preferably an alkoxyalkyl group, and most preferably a methoxypropyl group or a methoxybutyl group.

[0040] In the present disclosure, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film having a low melting point and little residual carbon, R 1 , R 3 , R 4 , R 6 , R 7 and R 9 are each independently selected from a sec-butyl group, a 1-methylbutyl group, a 1-dimethylamino-2-propyl group, and a 1-methoxy-2-butyl group; R 1 , R 3 , R 4 , R 6 , R 7 and R 9 four or five of R are isopropyl groups, 2 , R 5 and R 8 It is preferred that all of are hydrogen atoms.

[0041] The lanthanum compound represented by general formula (1) may be in the form of a solid or liquid at normal pressure and 25°C. However, in order to ensure transportability in the piping of a thin-film production apparatus, it is preferably in the form of a liquid at normal pressure and 25°C.

[0042] Preferred specific examples of the lanthanum compound represented by general formula (1) used in the thin-film-forming material of the present disclosure include the lanthanum compounds No. 1 to No. 232 below. However, the present disclosure is not limited to these lanthanum compounds. In the following chemical formulas, "Me" represents a methyl group, "Et" represents an ethyl group, "iPr" represents an isopropyl group, "iBu" represents an isobutyl group, "sBu" represents a sec-butyl group, and "tBu" represents a tert-butyl group.

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101] In the present disclosure, from the viewpoint of facilitating the production of a thin film-forming raw material that forms a high-quality thin film having a low melting point and little residual carbon, the thin film-forming raw material of the present disclosure preferably contains a lanthanum compound represented by No. 91, No. 97, No. 99, No. 109, No. 111, or No. 113, more preferably contains a lanthanum compound represented by No. 91, No. 97, or No. 99, and even more preferably contains a lanthanum compound represented by No. 97 or No. 99.

[0102] The lanthanum compound represented by general formula (1) is not particularly limited by its production method and can be produced by a well-known synthesis method, for example, by mixing La[N(SiMe3)2] with a compound having a ligand of the corresponding structure in the presence or absence of a solvent, and stirring the mixture to cause a reaction.

[0103] A2. Lanthanum Compound Represented by General Formula (2) In the present disclosure, from the viewpoint of facilitating the production of a thin film-forming raw material that has a low melting point and forms a high-quality thin film with little residual carbon, it is preferable that the lanthanum compound represented by the above general formula (1) contains a lanthanum compound represented by the following general formula (2). The thin film-forming raw material of the present disclosure may contain at least one lanthanum compound represented by the following general formula (2), and may contain two or more types.

[0104]

[0105] In general formula (2), R 10represents an aliphatic hydrocarbon group having from 4 to 8 carbon atoms or a heteroatom-containing hydrocarbon group having from 4 to 8 carbon atoms; R 12 , R 13 and R 15 each independently represents an aliphatic hydrocarbon group having from 1 to 4 carbon atoms or a heteroatom-containing hydrocarbon group having from 1 to 4 carbon atoms; R 11 and R 14 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X represents 1 or 2. 10 and R 12 And, R 13 and R 15 and are the same groups, and R 11 and R 14 Excluding lanthanum compounds in which

[0106] R 10 Examples of the aliphatic hydrocarbon group having from 4 to 8 carbon atoms represented by the formula (I) include groups having a corresponding number of carbon atoms in the aliphatic hydrocarbon group having from 1 to 8 carbon atoms, such as alkyl groups having from 4 to 8 carbon atoms (specifically, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, 1-methylbutyl group, 1-ethylpropyl group, neopentyl group, tert-pentyl group (1,1-dimethylpropyl group), n-hexyl group, isohexyl group, sec-hexyl group, tert-hexyl group, n-heptyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, n-octyl group, isooctyl group, sec-heptyl group, tert-octyl group, and 2-ethylhexyl group).

[0107] R 10Examples of heteroatom-containing hydrocarbon groups having 4 to 8 carbon atoms represented by the formula (I) include aliphatic hydrocarbon groups having 4 to 8 carbon atoms in which at least one hydrogen atom has been substituted with a halogen atom or an amino group, or in which some methylene groups have been substituted with oxygen atoms, or both. Examples of heteroatom-containing hydrocarbon groups having 5 to 8 carbon atoms include heteroatom-containing hydrocarbon groups having 1 to 8 carbon atoms in which the corresponding number of carbon atoms is present.

[0108] In the present disclosure, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film having a low melting point and little residual carbon, R 10 is preferably an aliphatic hydrocarbon group having from 4 to 8 carbon atoms, more preferably a branched aliphatic hydrocarbon group having from 4 to 8 carbon atoms, still more preferably a branched aliphatic hydrocarbon group having from 5 to 8 carbon atoms, particularly preferably a branched aliphatic hydrocarbon group having from 5 to 7 carbon atoms, and particularly preferably a branched alkyl group having from 5 to 7 carbon atoms.

[0109] In the present disclosure, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film having a low melting point and little residual carbon, R 12 , R 13 and R 15 are each independently preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, more preferably an aliphatic hydrocarbon group having 2 to 3 carbon atoms, even more preferably an aliphatic hydrocarbon group having 3 carbon atoms, and particularly preferably an isopropyl group.

[0110] In the present disclosure, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film having a low melting point and little residual carbon, R 11 and R 14 is preferably a hydrogen atom.

[0111] Specific examples of the lanthanum compound represented by general formula (2) include lanthanum compounds Nos. 13 to 40, 49 to 80, 85 to 116, 125 to 156, 165 to 196, and 201 to 232 listed above.

[0112] A3. Other Components The thin film-forming raw material of the present disclosure may contain the lanthanum compound represented by general formula (1) as a precursor of the thin film, and may contain other components depending on the type of the target thin film. Examples of such other components include other precursors, organic solvents, nucleophilic reagents, etc.

[0113] (1) Other precursors The other precursors are compounds containing metal atoms and / or metalloids and capable of forming a thin film, excluding the compound represented by general formula (1). When producing a thin film containing only lanthanum atoms as the metal, the thin film-forming raw material of the present disclosure can contain, as other precursors, metal compounds and metalloid compounds containing only lanthanum as the metal atom. When producing a thin film containing metal atoms other than lanthanum atoms, the thin film-forming raw material of the present disclosure can contain, in addition to the lanthanum compound represented by general formula (1), a compound containing the desired metal and / or a compound containing a metalloid.

[0114] In the present disclosure, the other precursor is not particularly limited, and can be any well-known precursor used as a raw material for forming a thin film by the ALD method, CVD method, etc. Examples of the other precursor include a reaction product of silicon or a metal with one or more compounds 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. Examples of the metal species of the precursor include lithium, sodium, potassium, magnesium, calcium, strontium, barium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, osmium, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, aluminum, gallium, indium, germanium, lead, antimony, bismuth, radium, scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

[0115] Examples of alcohol compounds that can be used as organic ligands for the other precursors include alkyl alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol, sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, pentyl alcohol, isopentyl alcohol, and tert-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, and 2-isopropoxy-1,1-dimethylethanol. ether alcohols such as 2-butoxy-1,1-dimethylethanol, 2-(2-methoxyethoxy)-1,1-dimethylethanol, 2-propoxy-1,1-diethylethanol, 2-sec-butoxy-1,1-diethylethanol, and 3-methoxy-1,1-dimethylpropanol; and dialkylamino alcohols such as dimethylaminoethanol, ethylmethylaminoethanol, diethylaminoethanol, dimethylamino-2-pentanol, ethylmethylamino-2-pentanol, dimethylamino-2-methyl-2-pentanol, ethylmethylamino-2-methyl-2-pentanol, and diethylamino-2-methyl-2-pentanol.

[0116] Examples of glycol compounds used as organic ligands for the other precursors 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, and 2,4-dimethyl-2,4-pentanediol.

[0117] Examples of the β-diketone compound used as the organic ligand for the other precursors 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- Examples of suitable fluorine-substituted alkyl β-diketones include 6-ethyldecane-3,5-dione and 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 and 1,3-diperfluorohexylpropane-1,3-dione; and ether-substituted β-diketones include 1,1,5,5-tetramethyl-1-methoxyhexane-2,4-dione, 2,2,6,6-tetramethyl-1-methoxyheptane-3,5-dione and 2,2,6,6-tetramethyl-1-(2-methoxyethoxy)heptane-3,5-dione.

[0118] Examples of the cyclopentadiene compound used as the organic ligand of the other precursor include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, isopropylcyclopentadiene, butylcyclopentadiene, sec-butylcyclopentadiene, isobutylcyclopentadiene, tert-butylcyclopentadiene, dimethylcyclopentadiene, tetramethylcyclopentadiene, and pentamethylcyclopentadiene.

[0119] Examples of the organic amine compound used as the organic ligand of the other precursor include methylamine, ethylamine, propylamine, isopropylamine, butylamine, sec-butylamine, tert-butylamine, isobutylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, ethylmethylamine, propylmethylamine, and isopropylmethylamine.

[0120] The other precursors described above are known in the art, and their production methods are also known. For example, when an alcohol compound is used as the organic ligand, the precursor can be produced by reacting the inorganic salt of the metal or a hydrate thereof described above with an alkali metal alkoxide of the alcohol compound. Examples of inorganic salts of metals or hydrates thereof include metal halides and nitrates. Examples of alkali metal alkoxides include sodium alkoxides, lithium alkoxides, and potassium alkoxides.

[0121] The multi-component ALD method described above includes a method in which each component of the thin film-forming raw material is supplied independently (hereinafter, sometimes referred to as a "single-source method"), and a method in which a multi-component raw material is mixed in advance to a desired composition and then vaporized and supplied as a mixed raw material (hereinafter, sometimes referred to as a "cocktail-source method"). When forming a thin film using the single-source method, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film with little residual carbon, the other precursor is preferably a compound whose thermal decomposition and / or oxidative decomposition behavior is similar to that of the lanthanum compound represented by general formula (1). When forming a thin film using the cocktail-source method, a mixture of the lanthanum compound represented by general formula (1) and the other precursor, or a mixed solution obtained by dissolving the mixture in the organic solvent, can be used as the thin film-forming raw material. However, the other precursor is preferably a compound whose thermal decomposition and / or oxidative decomposition behavior is similar to that of the lanthanum compound represented by general formula (1) and which does not undergo deterioration due to chemical reactions or the like when mixed.

[0122] In the present disclosure, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film with little residual carbon, the content of the other precursors is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 10 parts by mass or less, particularly even more preferably 5 parts by mass or less, and most preferably 0 part by mass, i.e., no other precursors are included, relative to 100 parts by mass of the thin film-forming raw material.

[0123] (2) Organic Solvent The thin film-forming material of the present disclosure may contain an organic solvent to dissolve the lanthanum compound represented by general formula (1) or the other precursors. The organic solvent is not particularly limited and may be any well-known organic solvent. Examples of the organic solvent include acetates 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; ketones such as methyl butyl ketone, methyl isobutyl ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone, methyl amyl ketone, cyclohexanone, and methylcyclohexanone; hydrocarbons such as hexane, cyclohexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, heptane, octane, toluene, and xylene; hydrocarbons having a cyano group such as 1-cyanopropane, 1-cyanonobutane, 1-cyanohexane, cyanocyclohexane, cyanobenzene, 1,3-dicyanopropane, 1,4-dicyanobutane, 1,6-dicyanohexane, 1,4-dicyanocyclohexane, and 1,4-dicyanobenzene; pyridine, lutidine, and the like. These organic solvents can be used alone or in combination as a mixture of two or more depending on the solubility of the solute, the relationship between the temperature at which the organic solvent is used and its boiling point and flash point, and the like.

[0124] When the thin film-forming raw material of the present disclosure contains the organic solvent, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film with little residual carbon, the blending amount of the organic solvent in the thin film-forming raw material is preferably adjusted so that the total amount of precursors in the thin film-forming raw material is 0.01 mol / L to 2.0 mol / L, and more preferably adjusted so that it is 0.05 mol / L to 1.0 mol / L.

[0125] Here, the total amount of precursors refers to the amount of the lanthanum compound represented by general formula (1) when the thin film-forming raw material does not contain any precursors other than the lanthanum compound represented by general formula (1). When the thin film-forming raw material contains other precursors in addition to the lanthanum compound represented by general formula (1), the total amount of the lanthanum compound represented by general formula (1) and the other precursors.

[0126] (3) Nucleophilic Reagent The thin film-forming material of the present disclosure may contain a nucleophilic reagent. Examples of the nucleophilic reagent include ethylene glycol ethers such as glyme, diglyme, triglyme, and tetraglyme, crown ethers such as 18-crown-6, dicyclohexyl-18-crown-6, 24-crown-8, dicyclohexyl-24-crown-8, and dibenzo-24-crown-8, ethylenediamine, N,N'-tetramethylethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, 1,1,4,7,7-pentamethyldiethylenetriamine, and 1,1,4,7,10,10-hexamethyltriethylenetetramine. Examples thereof include polyamines such as triethoxytriethyleneamine, cyclic polyamines such as cyclam and cyclen, heterocyclic compounds such as pyridine, pyrrolidine, piperidine, morpholine, N-methylpyrrolidine, N-methylpiperidine, N-methylmorpholine, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, oxazole, thiazole, and oxathiolane, β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, and 2-methoxyethyl acetoacetate, and β-diketones such as acetylacetone, 2,4-hexanedione, 2,4-heptanedione, 3,5-heptanedione, and dipivaloylmethane.

[0127] When the thin film-forming raw material of the present disclosure contains the above-mentioned nucleophilic reagent, the content of the above-mentioned nucleophilic reagent is preferably in the range of 0.1 mol or more and 10 mol or less, more preferably in the range of 0.5 mol or more and 8 mol or less, and even more preferably in the range of 1 mol or more and 4 mol or less, relative to 1 mol of the total amount of the precursor.

[0128] (4) Impurities It is desirable that the thin film forming material of the present disclosure contains as few impurities as possible, such as impurity metal elements, impurity halogens, impurity organic substances, and the like, other than the components that form the desired thin film.

[0129] Examples of the impurity metal element include metal elements different from the constituent metal atoms of the lanthanum compound represented by general formula (1) and the other precursors. From the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film with little residual carbon, the content of the impurity metal element in the thin film-forming material of the present disclosure is preferably 1 ppm or less, more preferably 100 ppb or less, even more preferably 10 ppb or less, and most preferably 1 ppb or less.

[0130] Examples of the impurity halogen component include halogen compounds containing halogen atoms such as chlorine and fluorine. From the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film with little residual carbon, the content of the impurity halogen component in the thin film-forming material of the present disclosure is preferably 100 ppm or less, more preferably 10 ppm or less, and even more preferably 1 ppm or less.

[0131] Examples of the impurity organic matter include organic components different from the organic substance constituting the lanthanum compound represented by general formula (1). From the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film with little residual carbon, the content of the impurity organic matter is preferably 500 ppm or less in total, more preferably 100 ppm or less, and even more preferably 50 ppm or less, in the thin-film-forming raw material of the present disclosure.

[0132] Furthermore, since moisture causes particle generation in the thin film-forming raw material and particle generation during thin film formation, it is desirable to remove moisture as much as possible from each component of the thin film-forming raw material before use. The moisture content of the lanthanum compound represented by general formula (1), the other precursors, the organic solvent, the nucleophilic reagent, etc. is preferably 10 ppm or less, and more preferably 1 ppm or less.

[0133] In order to reduce or prevent particle contamination of the thin film to be formed, it is preferable to prevent particles from being contained in the thin film-forming raw material as much as possible. Specifically, in particle measurement of the thin film-forming raw material using a light scattering liquid-borne particle detector, it is preferable that the number of particles larger than 0.3 μm per mL of the thin film-forming raw material be 100 or less, and it is more preferable that the number of particles larger than 0.2 μm per mL of the thin film-forming raw material be 100 or less.

[0134] A4. Form of Thin Film Forming Raw Material The form of the thin film forming raw material of the present disclosure is selected as appropriate depending on the transportation and supply method, etc., employed in chemical vapor deposition methods, including chemical vapor deposition and atomic layer deposition. The physical properties of the precursor lanthanum compound represented by general formula (1) are suitable for chemical vapor deposition methods, and since it has an ALD window, the thin film forming raw material of the present disclosure is particularly useful as a thin film forming raw material for atomic layer deposition.

[0135] The transport / supply method includes a "gas transport method" and a "liquid transport method." The gas transport method includes, for example, a step of vaporizing the thin film-forming raw material of the present disclosure in a container filled with the thin film-forming raw material (hereinafter referred to as a "raw material container") by heating and / or reducing pressure to obtain a raw material gas, and a step of introducing the raw material gas, optionally together with a carrier gas such as argon, nitrogen, or helium, into a film-forming chamber in which a substrate is placed. The liquid transport method includes, for example, a step of transporting the thin film-forming raw material of the present disclosure in a liquid state to a vaporization chamber, a step of vaporizing the thin film-forming raw material in the vaporization chamber by heating and / or reducing pressure to obtain a raw material gas, and a step of introducing the raw material gas, optionally together with a carrier gas such as argon, nitrogen, or helium, into a film-forming chamber in which a substrate is placed.

[0136] In the case of the gas transport method, the lanthanum compound represented by the general formula (1) can be used as the thin film-forming raw material. In the case of the liquid transport method, the lanthanum compound represented by the general formula (1) or a solution obtained by dissolving the lanthanum compound in the organic solvent can be used as the thin film-forming raw material. In addition, the thin film-forming raw material of the present disclosure can further contain other precursors, nucleophilic reagents, etc., as described above.

[0137] B. Thin Film Next, the thin film of the present disclosure will be described. The thin film of the present disclosure is produced using the above-described thin film-forming raw material, and is therefore a high-quality thin film with little residual carbon. The method for producing the thin film of the present disclosure is not limited as long as it is a method that can form a lanthanum-containing thin film using the thin film-forming raw material of the present disclosure, but for example, the method described below in "C. Thin Film Production Method" can be adopted.

[0138] The thin films disclosed herein include thin films of metallic lanthanum, lanthanum oxide, lanthanum nitride, lanthanum sulfide, etc., but the above-mentioned thin films can be made into desired types of thin films by appropriately selecting other precursors, reactive gases, and manufacturing conditions of the thin film manufacturing method described below. The thin films disclosed herein have excellent electrical and optical properties and can therefore be widely used in the manufacture of, for example, electrode materials for memory elements such as DRAM elements, wiring materials used in semiconductor elements such as logic elements, diamagnetic films used in the recording layers of hard disks, and catalyst materials for solid polymer fuel cells.

[0139] C. Thin Film Manufacturing Method Next, a thin film manufacturing method according to the present disclosure will be described. The thin film manufacturing method according to the present disclosure includes forming a lanthanum-containing thin film using the thin film-forming raw material. In the present disclosure, it is preferable to manufacture the thin film by a chemical vapor deposition method such as a CVD method or an ALD method, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film with little residual carbon.

[0140] The method for producing a lanthanum-containing thin film by a CVD method includes a step of forming a lanthanum-containing thin film by utilizing a surface reaction between a lanthanum compound in a source gas obtained by vaporizing the above-mentioned thin film-forming raw material and the surface of a substrate, or a gas-phase reaction between a lanthanum compound in the source gas and a reactive gas.

[0141] The method for producing a lanthanum-containing thin film by the ALD method includes a precursor thin film formation step of introducing a source gas obtained by vaporizing the above-mentioned thin film-forming source material into a film formation chamber in which a substrate is placed and depositing a lanthanum compound in the source gas on the surface of the substrate to form a precursor thin film, and a thin film formation step of introducing a reactive gas into the film formation chamber and reacting the precursor thin film with the reactive gas to form a lanthanum-containing thin film.

[0142] A well-known ALD apparatus can be used as an apparatus for producing a thin film using the thin film-forming material of the present disclosure. Specific examples of the apparatus include an apparatus capable of supplying a precursor by bubbling, as shown in FIGS. 1 and 3, and an apparatus having a vaporization chamber, as shown in FIGS. 2 and 4. Another example is an apparatus capable of performing plasma treatment on a reactive gas, as shown in FIGS. 3 and 4. It should be noted that the apparatus is not limited to the single-wafer apparatus equipped with a film-forming chamber as shown in FIGS. 1 to 4, but an apparatus capable of simultaneously processing multiple wafers using a batch furnace can also be used. These apparatuses can also be used as CVD apparatuses.

[0143] Hereinafter, the thin film manufacturing method will be described with reference to the drawings, taking the method of manufacturing a thin film by the ALD method as an example, and each step will be described. Note that the thin film forming raw materials used in the thin film manufacturing method of the present disclosure are the same as those described in the above section "A. Thin film forming raw materials," and therefore, description thereof will be omitted.

[0144] C1. Precursor Thin Film Formation Step In the precursor thin film formation step, a thin film-forming raw material is transported into source container 101 or vaporization chamber 102, and the thin film-forming raw material is vaporized to obtain a source gas. This source gas is supplied, together with carrier gases 110, 111 such as argon, nitrogen, or helium as necessary, into film formation chamber 100 in which a substrate is placed, and the lanthanum compound in the source gas is adsorbed and deposited on the surface of the substrate, thereby forming a precursor thin film.

[0145] (1) Transportation of Thin Film Forming Raw Material Methods for transporting the thin film forming raw material into the raw material container 101 or the vaporization chamber 102 include a gas transportation method, a liquid transportation method, a single source method, a cocktail source method, and the like.

[0146] As shown in Figures 1 and 3, an example of the gas transport method is to heat and / or vaporize the thin film-forming raw material in a raw material container 101 using a heater 103, and introduce the resulting raw material gas into the film-forming chamber 100, optionally together with carrier gases 110, 111, such as argon, nitrogen, or helium. The concentration of the raw material gas when introduced together with the carrier gases 110, 111 preferably contains 90% by volume or more, more preferably 99% by volume or more, of the lanthanum compound represented by general formula (1). As shown in Figures 2 and 4, an example of the liquid transport method is to transport the thin film-forming raw material in a liquid or solution state to a vaporization chamber 102, and then heat and / or vaporize the thin film-forming raw material in the vaporization chamber 102 to obtain a raw material gas, optionally together with carrier gases 110, 111, such as argon, nitrogen, or helium, and introduce the resulting raw material gas into the film-forming chamber 100.

[0147] The single-source method and the cocktail-source method are methods for transporting and supplying a thin-film-forming raw material containing multi-component precursors. The single-source method is a method in which precursors of each component are independently vaporized and supplied, while the cocktail-source method is a method in which a mixed raw material in which multi-component precursors are premixed is vaporized and supplied. The thin-film-forming raw material containing multi-component precursors may contain the nucleophilic reagents described above.

[0148] (2) Supply of Source Gas The thin film-forming source material may be vaporized in the source container 101 or in the vaporization chamber 102. In either case, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film with little residual carbon, the thin film-forming source material is preferably vaporized at a temperature of 0°C or higher and 300°C or lower, more preferably 0°C or higher and 250°C or lower, and even more preferably 30°C or higher and 200°C or lower.

[0149] When the thin film forming raw material is vaporized in the raw material container 101 or the vaporization chamber 102 to form a raw material gas, the pressure in the raw material container 101 or the vaporization chamber 102 is preferably in the range of 1 Pa or more and 10,000 Pa or less, more preferably in the range of 10 Pa or more and 5,000 Pa or less, and even more preferably in the range of 20 Pa or more and 1,000 Pa or less, from the viewpoint of achieving good vaporization of the thin film forming raw material.

[0150] When the source gas is introduced into the film formation chamber 100, the source gas can be introduced into the film formation chamber 100 together with carrier gases 110, 111 such as argon, nitrogen, or helium, as necessary. When the source gas is introduced into the film formation chamber 100 using the carrier gases 110, 111, the source gas preferably contains 90% by volume or more, and more preferably 99% by volume or more, of the lanthanum compound gas represented by general formula (1).

[0151] (3) Formation of Precursor Thin Film As a method for forming a precursor thin film on a substrate placed in the deposition chamber 100 using a source gas, for example, a method utilizing a surface reaction between a lanthanum compound represented by general formula (1) in the source gas and the surface of the substrate can be mentioned. In the method utilizing the surface reaction, the source gas is brought into contact with the substrate, and the lanthanum compound represented by general formula (1) in the source gas is adsorbed and deposited on the substrate to form a precursor thin film. Heating the substrate or the deposition chamber 100 containing the substrate promotes the surface reaction, but increases damage to the substrate due to the high temperature. Therefore, the substrate or the deposition chamber 100 containing the substrate is preferably heated at a temperature in the range of room temperature to 500°C, more preferably in the range of 100°C to 450°C, even more preferably in the range of 130°C to 400°C, and particularly preferably in the range of 150°C to 300°C.

[0152] The pressure (system pressure) inside the film formation chamber 100 in this step is preferably 1 Pa or more and 10,000 Pa or less, and more preferably 10 Pa or more and 1,000 Pa or less from the viewpoint of facilitating the production of a uniform precursor thin film.

[0153] In the present disclosure, the term "deposited" is a concept that includes chemical adsorption of a lanthanum compound on the surface of a substrate, and the term "on a substrate" refers to the surface of a substrate or a lanthanum-containing thin film formed in a thin film formation step described below, i.e., the surface of a lanthanum-containing thin film grown by the thin film manufacturing method of the present disclosure.

[0154] Examples of materials for the substrate include silicon, ceramics such as silicon nitride, titanium nitride, tantalum nitride, titanium oxide, molybdenum oxide, zirconium oxide, hafnium oxide, and lanthanum oxide, glass, and metals such as metallic cobalt, metallic molybdenum, molybdenum sulfide, molybdenum selenide, tungsten sulfide, and tungsten selenide. Examples of the shape of the substrate include plate-like, spherical, fibrous, scale-like, flat, and disk-like plates, fibrous, cylindrical, prismatic, cylindrical, spiral, spherical, ring-like, and three-dimensional structures such as trench structures.

[0155] C2. Thin Film Formation Process In the thin film formation process, a reactive gas 107 is introduced into the film formation chamber 100, and a thin film containing lanthanum atoms can be formed by utilizing a chemical reaction between the precursor thin film and the reactive gas 107.

[0156] In this process, a thin film of an oxide, nitride, or metal can be formed by appropriately selecting the type of reactive gas 107. Examples of the reactive gas 107 to react with the precursor thin film include oxidizing gases such as oxygen, ozone, nitrogen dioxide, nitric oxide, water vapor, hydrogen peroxide, formic acid, acetic acid, and acetic anhydride; reducing gases such as hydrogen; organic amine compounds such as monoalkylamines, dialkylamines, trialkylamines, and alkylenediamines; nitriding gases such as hydrazine and ammonia; and sulfurizing gases such as sulfur, hydrogen sulfide, and dialkyl sulfides such as dimethyl sulfide, diethyl sulfide, and diisopropyl sulfide. These reactive gases 107 may be used alone or in combination of two or more. In the present disclosure, from the viewpoint of facilitating the formation of a high-quality lanthanum-containing thin film with little residual carbon, the reactive gas 107 preferably contains at least one selected from the group consisting of hydrogen, oxygen, ozone, water vapor, ammonia, and dialkyl sulfide, more preferably contains at least one selected from the group consisting of hydrogen, oxygen, ozone, water vapor, and ammonia, and even more preferably contains at least one selected from the group consisting of ozone and water vapor.

[0157] In this step, the water vapor used as the reactive gas 107 may be a gas consisting of water vapor alone, or may be a mixed gas containing water vapor and other gases such as argon, nitrogen, oxygen, and hydrogen. When the reactive gas 107 is the mixed gas, the concentration of water vapor in the mixed gas is preferably in the range of 0.001% by volume to 99% by volume, more preferably in the range of 0.001% by volume to 50% by volume, and even more preferably in the range of 0.001% by volume to 10% by volume, from the viewpoint of improving the reaction between the precursor thin film and the reactive gas 107.

[0158] In this step, a thermal reaction, plasma, photoreaction, or the like may be used to promote the formation of the thin film.

[0159] Examples of methods that utilize a thermal reaction include a method of heating the substrate, or a method of heating the inside of the film formation chamber 100 in which the substrate is placed. The heater for heating may be installed outside the film formation chamber 100, or may be installed inside the film formation chamber 100 to heat only the substrate and its surroundings. The heating temperature in this step may be in the range of room temperature or higher and 500°C or lower, preferably in the range of 100°C or higher and 450°C or lower, more preferably in the range of 130°C or higher and 400°C or lower, and even more preferably in the range of 150°C or higher and 300°C or lower.

[0160] In addition, the pressure (system pressure) within the film formation chamber 100 in this process is preferably in the range of 1 Pa or more and 10,000 Pa or less, and from the viewpoint of ensuring good reaction between the precursor thin film and the reactive gas 107, it is more preferably in the range of 10 Pa or more and 1,000 Pa or less.

[0161] An example of a method using plasma is to generate plasma in the film formation chamber 100 and excite the precursor thin film, the substrate, or the reactive gas 107. An example of a mechanism for generating plasma is to generate plasma by applying a high-frequency voltage to the film formation chamber 100 using a radio-frequency (RF) power supply 113 installed outside the film formation chamber 100. In this step, if the power when applying the voltage is too high, the damage to the substrate will be significant, so the power is preferably in the range of 10 W or more and 1,500 W or less, more preferably in the range of 30 W or more and 1,000 W or less, and even more preferably in the range of 50 W or more and 600 W or less.

[0162] Examples of methods that utilize photoreaction include methods that use ultraviolet lamps (particularly low-pressure mercury lamps, etc.), which can suppress film damage caused by charged particles compared to methods that utilize plasma.

[0163] C3. Other Steps The method for producing a thin film according to the present disclosure may include other steps such as an exhaust step, an annealing step, and a reflow step.

[0164] (1) Exhaust Step The thin film manufacturing method of the present disclosure may include an exhaust step, after the above "C1. Precursor Thin Film Formation Step" or after the above "C2. Thin Film Formation Step", in which source gases not involved in the formation of the precursor thin film or thin film, reactive gas 107, and by-product gases generated during the formation of the precursor thin film or thin film are exhausted 109 from the film formation chamber 100. In the exhaust step, it is ideal that the source gases, reactive gas 107, and by-product gases are completely exhausted from the film formation chamber 100, but complete exhaust is not necessarily required. Examples of exhaust methods include a method of purging by introducing a purge gas 108 such as helium, nitrogen, or argon into the film formation chamber 100, a method of exhausting by reducing the pressure inside the film formation chamber 100, and a combination of these methods. The degree of pressure reduction when reducing the pressure inside the film formation chamber 100 is preferably within a range of 0.01 Pa or more and 300 Pa or less, more preferably within a range of 0.05 Pa or more and 200 Pa or less, and even more preferably within a range of 0.1 Pa or more and 100 Pa or less, from the viewpoint that the source gas, reactive gas 107, and by-product gas are sufficiently exhausted 109, and a high-quality lanthanum-containing thin film with little residual carbon is easily formed.

[0165] (2) Annealing Step The thin film manufacturing method of the present disclosure can include a step of annealing the lanthanum-containing thin film after its formation to improve the electrical properties of the lanthanum-containing thin film. In the annealing step, the lanthanum-containing thin film can be annealed in an inert atmosphere, an oxidizing atmosphere, or a reducing atmosphere. The temperature in the annealing step is preferably, for example, in the range of 200°C to 600°C, more preferably in the range of 230°C to 550°C, and even more preferably in the range of 250°C to 500°C, from the viewpoint of easily forming a high-quality lanthanum-containing thin film with little residual carbon.

[0166] (3) Reflow Step The method for producing a thin film according to the present disclosure may include a reflow step for filling in any unevenness in the lanthanum-containing thin film. From the viewpoint of easily forming a high-quality lanthanum-containing thin film with little residual carbon, the reflow step is preferably carried out at a temperature in the range of 200° C. to 600° C., more preferably 230° C. to 550° C., and even more preferably 250° C. to 500° C.

[0167] C4. Film Formation Cycle In the thin film manufacturing method of the present disclosure, a precursor thin film formation step, an evacuation step, a thin film formation step, and an evacuation step are performed in sequence, and the formation of a lanthanum-containing thin film through a series of operations constitutes one cycle. By repeating this cycle, a lanthanum-containing thin film having a desired thickness can be manufactured. That is, the thickness of the manufactured lanthanum-containing thin film can be controlled by the number of cycles. For example, the above cycle may be performed only once to manufacture a single layer of lanthanum-containing thin film, or may be performed twice or more to manufacture a lanthanum-containing thin film having a desired thickness. From the viewpoint of facilitating the production of a uniform lanthanum-containing thin film, the thickness of the lanthanum-containing thin film obtained per cycle is preferably 0.01 nm to 10 nm, more preferably 0.03 nm to 5 nm, and even more preferably 0.05 nm to 1 nm.

[0168] C5. Thin Film Manufacturing Methods Other Than ALD Methods In this embodiment, a method for manufacturing a lanthanum-containing thin film by ALD has been described, but the method for manufacturing a thin film of the present disclosure is not limited to the above and may include, for example, a CVD method in which a lanthanum compound in a source gas obtained by vaporizing a thin film-forming raw material is decomposed, or a lanthanum compound is reacted with a reactive gas to form a lanthanum-containing thin film. Furthermore, in addition to the above-mentioned ALD and CVD methods, thin films may also be manufactured by MOD methods such as sputtering, ion plating, coating pyrolysis, and sol-gel methods. Among these, ALD methods are preferred for manufacturing thin films because they have many advantages, such as excellent composition controllability and step coverage, suitability for mass production, and the ability to achieve hybrid integration.

[0169] D. Lanthanum Compound The present disclosure provides a lanthanum compound represented by the above general formula (2). The lanthanum compound represented by the above general formula (2) can be the same as that described in the section "A2. Lanthanum compound represented by general formula (2)" in "A. Thin-film-forming raw material," and therefore, further description here will be omitted.

[0170] E. Others The present disclosure includes the following aspects.

[0171] [1] A thin film-forming material containing a lanthanum compound represented by the following general formula (1): (In general formula (1), R 1 , R 3 , R 4 , R 6 , R 7 and R 9 each independently represents an aliphatic hydrocarbon group having from 1 to 8 carbon atoms or a heteroatom-containing hydrocarbon group having from 1 to 8 carbon atoms; R 2 , R 5 and R 8 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 1 and R 3 And, R 4 and R 6 And, R 7 and R 9 and are all the same group, and R 2 , R 5 and R 8 [2] The thin film forming material according to [1], which is for an atomic layer deposition method. [3] R 1 , R 3 , R 4 , R 6 , R 7 and R 9 are each independently selected from a sec-butyl group, a 1-methylbutyl group, a 1-dimethylamino-2-propyl group, and a 1-methoxy-2-butyl group; R 1 , R 3 , R 4 , R 6 , R 7 and R9 four or five of R are isopropyl groups, 2 , R 5 and R 8 [4] The thin film-forming material according to [1] or [2], wherein all of the lanthanum compounds are hydrogen atoms. [5] The thin film-forming material according to [1] or [2], wherein the lanthanum compound is selected from No. 91, No. 97, No. 99, No. 109, No. 111, and No. 113. [5] A thin film produced using the thin-film-forming raw material according to any one of [1] to [4]. [6] A method for producing a thin film, comprising forming a thin film containing lanthanum atoms using the thin-film-forming raw material according to any one of [1] to [4]. [7] A method for producing a thin film according to [6], comprising decomposing a lanthanum compound in a raw material gas obtained by vaporizing the thin-film-forming raw material, or reacting the lanthanum compound with a reactive gas, to form a thin film containing lanthanum atoms. [8] A method for producing a thin film according to [7], comprising: a precursor thin-film formation step of introducing a raw material gas obtained by vaporizing the thin-film-forming raw material into a film-forming chamber in which a substrate is placed, and forming a precursor thin film on the surface of the substrate; and a thin-film formation 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 lanthanum atoms. [9] A lanthanum compound represented by the following general formula (2): (In general formula (2), R 10 represents an aliphatic hydrocarbon group having from 4 to 8 carbon atoms or a heteroatom-containing hydrocarbon group having from 4 to 8 carbon atoms; R 12 , R 13 and R 15 each independently represents an aliphatic hydrocarbon group having from 1 to 4 carbon atoms or a heteroatom-containing hydrocarbon group having from 1 to 4 carbon atoms; R 11 and R 14 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X represents 1 or 2. 10 and R 12 And, R 13 and R 15 and are the same group, and R 11 and R14 Excluding lanthanum compounds in which

[0172] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the following examples.

[0173] [Example 1] Preparation of Lanthanum Compound No. 97 Under an argon atmosphere, La[N(SiMe3)2]3 (2.26 g, 0.00365 mol) and toluene (5.8 mL) were charged into a 100 mL three-neck flask and cooled on ice. A mixed solution of N-isopropyl-N'-sec-pentylformamidine (0.57 g, 0.00365 mol) and toluene (2.9 mL) was added dropwise thereto, and the mixture was warmed to room temperature and stirred for 18 hours. Thereafter, the mixture was again ice-cooled, and a mixed solution of N,N'-diisopropylformamidine (0.93 g, 0.00729 mol) and toluene (2.9 mL) was added dropwise thereto. The mixture was warmed to room temperature and stirred for 18 hours. After stirring, the organic layer was desolvated, and the residue was distilled using a Kugelrohr distillation apparatus at a temperature of 150°C and a pressure of 32 Pa to obtain a colorless, transparent liquid (yield: 1.29 g, 64%). The obtained colorless, transparent liquid was cooled at room temperature to become a white solid. The white solid was analyzed as follows and identified as the target lanthanum compound No. 97.

[0174] (Analysis Values) (1) Atmospheric Pressure TG-DTA Temperature at 50% mass loss: 240°C (Ar flow rate: 100 mL / min, temperature rise: 10°C / min, sample amount: 10.119 mg) (2) 1 H-NMR (solvent: deuterated benzene) (chemical shift: multiplicity: hydrogen number) (0.942-0.976: triplet: 3) (1.202-1.241: multiplet: 33) (1.256-1.551: multiplet: 4) (2.882-2.928: multiplet: 1) (3.086-3.181: multiplet: 5) (8.381: singlet: 2) (8.391: singlet: 1)

[0175] [Example 2] Preparation of Lanthanum Compound No. 99 Under an argon atmosphere, La[N(SiMe3)2]3 (16.13 g, 0.02601 mol) and toluene (41 mL) were charged into a 200 mL three-neck flask and cooled on ice. A mixed solution of N-sec-pentyl-N'-isopropylformamidine (8.13 g, 0.05202 mol) and toluene (21 mL) was added dropwise thereto, the temperature was raised to room temperature, and the mixture was stirred for 22 hours. After stirring, the mixture was again cooled on ice, and a mixed solution of N,N'-diisopropylformamidine (3.34 g, 0.02601 mol) and toluene (21 mL) was added dropwise thereto, the temperature was raised to room temperature, and the mixture was stirred for 18 hours. After stirring, the organic layer was desolvated, and the residue was distilled at a temperature of 175°C and a pressure of 34 Pa to obtain a pale yellow liquid (yield: 9.46 g, 63%). The obtained pale yellow liquid was subjected to the following analysis and identified as the target lanthanum compound No. 99.

[0176] (1) Atmospheric pressure TG-DTA Temperature at 50% mass loss: 254°C (Ar flow rate: 100 mL / min, temperature rise: 10°C / min, sample amount: 9.794 mg) (2) 1 H-NMR (solvent: deuterated benzene) (chemical shift: multiplicity: hydrogen number) (0.943-0.978: triplet: 6) (1.201-1.240: multiplet: 30) (1.300-1.528: multiplet: 8) (2.893: multiplet: 2) (3.086-3.161: multiplet: 4) (8.399: multiplet: 3)

[0177] [Example 3] Preparation of Lanthanum Compound No. 91 Under an argon atmosphere, La[N(SiMe3)2]3 (2.26 g, 0.00365 mol) and toluene (5.8 mL) were charged into a 100 mL three-neck flask and cooled on ice. Next, a mixed solution of N-isopropyl-N'-sec-butylformamidine (1.14 g, 0.00729 mol) and toluene (2.9 mL) was added dropwise, the mixture was warmed to room temperature, and the mixture was stirred for 18 hours. After stirring, the mixture was again cooled on ice, and a mixed solution of N,N'-diisopropylformamidine (0.47 g, 0.00365 mol) and toluene (2.9 mL) was added dropwise. The mixture was warmed to room temperature and stirred for 18 hours. After stirring, the organic layer was desolvated, and the residue was distilled using a Kugelrohr distillation apparatus at a temperature of 145°C and a pressure of 23 Pa to obtain a pale yellow solid (yield: 1.32 g, 66%). The obtained pale yellow solid was subjected to the following analysis and identified as the target lanthanum compound No. 91.

[0178] (1) Atmospheric pressure TG-DTA Temperature at 50% mass loss: 243°C (Ar flow rate: 100 mL / min, temperature rise: 10°C / min, sample amount: 9.975 mg) (2) 1 H-NMR (solvent: deuterated benzene) (chemical shift: multiplicity: hydrogen number) (0.919-0.956: triplet: 6) (1.201-1.239: multiplet: 30) (1.468-1.539: quintet: 4) (2.749-2.829: sextet: 2) (3.085-3.163: multiplet: 4) (8.393: multiplet: 3)

[0179] [Evaluation Example] Evaluation of Physical Properties of Compounds The lanthanum compounds obtained in Examples 1 to 3 and the following comparative compounds were used to carry out the following evaluations.

[0180]

[0181] (1) Temperature (°C) at 50% mass reduction in atmospheric pressure TG-DTA Measurements were performed using a TG-DTA at 760 Torr, an argon flow rate of 100 mL / min, a heating rate of 10°C / min, and a scanning temperature range of 30°C to 600°C. The temperature (°C) at which the weight of the test compound had decreased by 50% by mass was evaluated as the "temperature (°C) at 50% mass reduction in atmospheric pressure TG-DTA." A lower temperature (°C) at 50% mass reduction in atmospheric pressure TG-DTA indicates that vapor can be obtained at a lower temperature. The results are shown in Table 1.

[0182] (2) Melting Point Evaluation (°C) The state of the compound at normal pressure and 25°C was visually observed. For compounds that were solid at 25°C, measurements were performed using a differential scanning calorimeter (DSC) at a heating rate of 10°C / min over a scanning temperature range of 30°C to 600°C. In the resulting chart, the melting point (°C) was evaluated as the temperature at the intersection of a straight line extending the low-temperature baseline toward the high-temperature side and a tangent drawn at the point where the gradient of the curve on the low-temperature side of the peak indicating an endothermic reaction is maximum. The results are shown in Table 1.

[0183] (3) Thermal decomposition onset temperature (°C) Using a differential scanning calorimeter (DSC), measurements were taken at a heating rate of 10°C / min in a scanning temperature range of 30°C to 600°C. In the DSC chart, the onset of an exothermic or endothermic peak of the compound was evaluated as the thermal decomposition onset temperature (°C). The results are shown in Table 1.

[0184]

[0185] Example 4: Production of a thin film by ALD using lanthanum compound No. 97 Using lanthanum compound No. 97 obtained in Example 1 above as a thin film-forming raw material, a thin film containing lanthanum oxide was produced on a silicon substrate as a base by ALD under the following conditions using the ALD apparatus shown in FIG.

[0186] (Conditions) Manufacturing method: ALD method Reaction temperature (substrate temperature): 200°C Reactive gas: ozone

[0187] (Steps) A series of steps (1) to (4) below constitute one cycle, and 50 cycles were repeated. (1) The vapor of a thin-film-forming raw material (raw material gas: lanthanum compound No. 97) obtained by vaporization under conditions of a raw material container temperature of 140°C and a raw material container internal pressure of 67 Pa was introduced into a film-forming chamber, and the lanthanum compound in the raw material gas was deposited on the surface of the substrate for 10 seconds at a system pressure of 67 Pa to form a precursor thin film (precursor thin-film forming step). (2) Undeposited raw material gas was purged with argon for 20 seconds (exhaust step). (3) A reactive gas was introduced into the film-forming chamber, and the precursor thin film and the reactive gas were reacted for 10 seconds at a system pressure of 67 Pa (thin-film forming step). (4) Unreacted reactive gas and by-product gas were purged with argon for 20 seconds (exhaust step).

[0188] Example 5: Fabrication of a thin film by ALD using lanthanum compound No. 97 A thin film containing lanthanum oxide was fabricated on a silicon substrate using the same procedure as in Example 4, except that the reactive gas was changed from ozone to water vapor, (3) the supply time of the reactive gas in the thin film formation step was changed from 10 seconds to 0.1 seconds, and (4) the argon purge time in the exhaust step was changed from 20 seconds to 120 seconds.

[0189] Example 6 Production of Thin Film by ALD Using Lanthanum Compound No. 99 A thin film containing lanthanum oxide was produced on a silicon substrate by the same procedure as in Example 4, except that the thin film-forming source material was changed from Lanthanum Compound No. 97 to Lanthanum Compound No. 99, and the source container temperature in (1) the precursor thin film formation step was changed from 140° C. to 150° C.

[0190] Example 7: Fabrication of a thin film by ALD using lanthanum compound No. 99 A thin film containing lanthanum oxide was fabricated on a silicon substrate using the same procedure as in Example 6, except that the reactive gas was changed from ozone to water vapor, (3) the supply time of the reactive gas in the thin film formation step was changed from 10 seconds to 0.1 seconds, and (4) the argon purge time in the exhaust step was changed from 20 seconds to 120 seconds.

[0191] Comparative Example 1: Production of a thin film by ALD using a comparative compound A thin film containing lanthanum oxide was produced on a silicon substrate by the same procedure as in Example 4, except that the thin film-forming source material was changed from lanthanum compound No. 97 to the comparative compound, and the source container temperature in (1) the precursor thin film formation step was changed from 140° C. to 110° C.

[0192] Comparative Example 2: Production of a thin film by ALD using a comparative compound A thin film containing lanthanum oxide was produced on a silicon substrate using the same procedure as in Comparative Example 1, except that the reactive gas was changed from ozone to water vapor, (3) the supply time of the reactive gas in the thin film formation step was changed from 10 seconds to 0.1 seconds, and (4) the argon purge time in the exhaust step was changed from 20 seconds to 120 seconds.

[0193] (Evaluation) For the thin films obtained in Examples 4 to 7 and Comparative Examples 1 and 2, the thickness of the thin film was measured by X-ray reflectivity, the surface of the thin film was observed using SEM images, the composition of the thin film was analyzed by X-ray diffraction, and the carbon content in the thin film was measured by X-ray photoelectron spectroscopy. These results are shown in Table 2.

[0194]

[0195] Comparison of the lanthanum compounds obtained in Examples 1 and 2 above with the comparative compounds revealed that the lanthanum compound represented by general formula (1) is a liquid or a low-melting-point solid at room temperature, suggesting the supply stability of the thin-film-forming raw material in the thin-film manufacturing equipment. Because the comparative compound was a high-melting-point solid, there is a risk of blockage in the supply line of the thin-film manufacturing equipment, raising concerns about the supply stability of the thin-film-forming raw material. Furthermore, it was confirmed that Examples 4 to 7, which used a thin-film-forming raw material containing the lanthanum compound represented by general formula (1), had flat thin film surfaces, and were able to form high-quality lanthanum-containing thin films with less residual carbon than Comparative Examples 1 and 2, which used a thin-film-forming raw material containing the comparative compound.

[0196] From the above, it was found that the thin film-forming raw material containing the lanthanum compound represented by the general formula (1) had a low melting point and was able to form a high-quality lanthanum-containing thin film with little residual carbon.

[0197] 100 Film formation chamber 101 Source container 102 Vaporization chamber 103 Heater 104 Mass flow controller (MFC) 105 Vacuum pump 106 Cold trap 107 Reactive gas 108 Purge gas 109 Exhaust 110 Carrier gas 111 Carrier gas 112 Automatic pressure controller 113 Radio frequency (RF) power supply 114 RF matching system

Claims

1. A thin film forming material containing a lanthanum compound represented by the following general formula (1): (In general formula (1), R 1 , R 3 , R 4 , R 6 , R 7 and R 9 each independently represents an aliphatic hydrocarbon group having from 1 to 8 carbon atoms or a heteroatom-containing hydrocarbon group having from 1 to 8 carbon atoms; R 2 , R 5 and R 8 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 1 and R 3 And, R 4 and R 6 And, R 7 and R 9 are all the same group, and R 2 , R 5 and R 8 Excluding lanthanum compounds in which all are the same group.) 2. The thin film forming material according to claim 1, wherein the thin film forming material is for use in an atomic layer deposition method.

3. R 1 , R 3 , R 4 , R 6 , R 7 and R 9 one or two of R are each independently selected from sec-butyl, 1-methylbutyl, 1-dimethylamino-2-propyl, and 1-methoxy-2-butyl; 1 , R 3 , R 4 , R 6 , R 7 and R 9 four or five of R are isopropyl groups; 2 , R 5 and R 8 The thin film forming material according to claim 1 or 2, wherein all of the above are hydrogen atoms.

4. The thin film forming material according to claim 1 or 2, wherein the lanthanum compound is selected from No. 91, No. 97, No. 99, No. 109, No. 111 and No.

113.

5. A thin film produced by using the thin film forming material according to claim 1 or 2.

6. A method for producing a thin film, comprising forming a thin film containing lanthanum atoms by using the thin film forming material according to claim 1 or 2.

7. A method for producing a thin film according to claim 6, comprising decomposing a lanthanum compound in a source gas obtained by vaporizing the thin film-forming source, or reacting the lanthanum compound with a reactive gas to form a thin film containing lanthanum atoms.

8. A method for producing a thin film according to claim 7, comprising: a precursor thin film formation step of introducing a raw material gas obtained by vaporizing the thin film forming raw material into a film formation chamber in which a substrate is placed, and forming a precursor thin film on the surface of the substrate; and a thin film formation step of introducing a reactive gas into the film formation chamber, and reacting the precursor thin film with the reactive gas, to form a thin film containing lanthanum atoms.

9. A lanthanum compound represented by the following general formula (2): (In general formula (2), R 10 represents an aliphatic hydrocarbon group having from 4 to 8 carbon atoms or a heteroatom-containing hydrocarbon group having from 4 to 8 carbon atoms; R 12 , R 13 and R 15 each independently represents an aliphatic hydrocarbon group having from 1 to 4 carbon atoms or a heteroatom-containing hydrocarbon group having from 1 to 4 carbon atoms; R 11 and R 14 Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X represents 1 or 2. 10 and R 12 And, R 13 and R 15 and R are the same group, 11 and R 14 Excluding lanthanum compounds in which

Images