Method for manufacturing semiconductor substrate and film-forming composition

Abstract

Provided are: a method for manufacturing a semiconductor substrate on which a film (metal hard mask) that has excellent cleaning properties for peripheral edge sections of the substrate in film formation and that has excellent etching resistance can be formed; and a film-forming composition. The present invention provides a method for manufacturing a semiconductor substrate, the method including a step for coating a substrate with a film-forming composition, wherein: the film-forming composition contains a metal compound composed of at least one type of metal atom and at least one type of organic acid, and a solvent; and the metal atom has a boiling point of 700°C or higher when the metal atom is a metal fluoride.

Description

Semiconductor substrate manufacturing method and film-forming composition

[0001] The present invention relates to a method for producing a semiconductor substrate and a film-forming composition.

[0002] In a multilayer resist process for manufacturing semiconductor substrates and the like, a metal hard mask composition has been proposed as a resist underlayer film (see JP 2013-185155 A). A CleanTrack (manufactured by Tokyo Electron Limited) or the like is used as a manufacturing device for semiconductor substrates and the like. This device is capable of consistently performing processes such as spin coating, EBR (Edge Bead Removal), back-rinsing, and baking. EBR is a process in which a coating is formed on a substrate (wafer) by spin coating, and then the substrate is cleaned with a cleaning solution to remove the coating from the edge (periphery) of the substrate.

[0003] JP 2013-185155 A

[0004] Although the above-mentioned device automatically transports substrates, EBR is required to prevent contamination of the tweezers holding the substrate. If the substrate edge cannot be cleaned by EBR, the wafer transport arm and other components may become contaminated, which may cause defects in the semiconductor substrate and reduce device yield. Therefore, films formed using metal hard mask compositions are required to have etching resistance in multilayer resist processes as well as cleanability by EBR of the metal hard mask at the substrate periphery.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a method for producing a semiconductor substrate and a film-forming composition that enable the formation of a film (metal hard mask) that exhibits good cleaning properties at the peripheral edge of the substrate during film formation and has excellent etching resistance.

[0006] In one embodiment, the present invention relates to a method for producing a semiconductor substrate, comprising: applying a film-forming composition to a substrate; wherein the film-forming composition contains: a metal compound (hereinafter also referred to as "compound [A]") composed of at least one metal atom and at least one organic acid; and a solvent (hereinafter also referred to as "solvent [B]"); and the metal atom is a metal atom having a boiling point of 700°C or higher when in the form of a metal fluoride.

[0007] In another embodiment, the present invention relates to a film-forming composition comprising: a metal compound composed of at least one metal atom and at least one organic acid; and a solvent, wherein the metal atom is a metal atom having a boiling point of 700°C or higher when in the form of a metal fluoride.

[0008] In this specification, the "periphery" of a substrate refers to, for example, a peripheral portion of the substrate having a length from the outer edge to the center of the substrate of 3.0 cm or less. The length from the outer edge to the center of the substrate can be 2.0 cm, 1.0 cm, 0.5 cm, or 0.2 cm. "Organic acid" refers to an organic compound that exhibits acidity, and "organic compound" refers to a compound having at least one carbon atom.

[0009] According to this method for producing a semiconductor substrate, the cleaning property of the peripheral portion of the substrate during film formation is excellent, and the etching resistance of the film is excellent, so that a well-patterned semiconductor substrate can be efficiently obtained. According to this film-forming composition, the cleaning property of the peripheral portion of the substrate during film formation is excellent, and a film having excellent etching resistance can be formed. Therefore, these compositions can be suitably used in the production of semiconductor devices, which are expected to become even more miniaturized in the future.

[0010] <<Method for Producing Semiconductor Substrate>> The method for producing a semiconductor substrate includes a step of applying a film-forming composition to a substrate (hereinafter also referred to as a “coating step”). Preferably, the method for producing a semiconductor substrate further includes a step of directly or indirectly forming a resist pattern on the resist underlayer film formed in the coating step (hereinafter also referred to as a “resist pattern forming step”), and a step of forming a pattern on the film by etching using the resist pattern as a mask (hereinafter also referred to as an “etching step”).

[0011] The method for producing a semiconductor substrate may further include, as necessary, a step of forming an organic underlayer film directly or indirectly on the substrate having the resist underlayer film formed in the coating step (hereinafter also referred to as an "organic underlayer film forming step") prior to the resist pattern forming step.

[0012] The method for producing a semiconductor substrate may further include, as necessary, a step of forming a silicon-containing film directly or indirectly on the substrate having the resist underlayer film formed in the coating step (hereinafter also referred to as a "silicon-containing film forming step") prior to the resist pattern forming step.

[0013] The method for manufacturing a semiconductor substrate may further include, as necessary, a step of cleaning the peripheral portion of the substrate with a cleaning liquid after the coating step and before the resist pattern forming step (hereinafter also referred to as a "cleaning step").

[0014] First, the film-forming composition used in the method for manufacturing a semiconductor substrate will be described, followed by a description of the steps in the case where the method includes a resist pattern forming step and an etching step, which are preferred steps, and an organic underlayer film forming step and a silicon-containing film forming step, which are optional steps.

[0015] <Film-forming composition> The composition contains the compound (A) and the solvent (B). The composition may contain other optional components as long as the effects of the present invention are not impaired.

[0016] [Compound [A]] The compound [A] refers to a compound composed of at least one metal atom and at least one organic acid. The metal atom constituting the compound [A] is a metal atom having a boiling point of 700°C or higher when in the form of a metal fluoride. The metal atom is preferably at least one selected from the group consisting of magnesium, calcium, strontium, barium, scandium, yttrium, manganese, cobalt, nickel, zinc, aluminum, gallium, indium, tin, lead, and lanthanoids, more preferably at least one selected from the group consisting of magnesium, lanthanum, zinc, and aluminum. The valence of the metal atom is preferably divalent to tetravalent depending on the type of metal atom, and more preferably divalent. Metal oxide films derived from metal compounds containing metal atoms having a boiling point of 700°C or higher when in the form of a metal fluoride are expected to have excellent etching resistance. References include WO2024-142795 and WO2010-044400. Furthermore, it is presumed that a metal oxide film derived from a metal compound containing a metal atom having a boiling point of 700°C or higher in the case of a metal fluoride is easily dissolved in an acid such as hydrochloric acid and is easily removed with an acid such as hydrochloric acid. In the case of a metal fluoride, the boiling point is preferably 800°C or higher, more preferably 900°C or higher, and even more preferably 990°C or higher.

[0017] The compound (A) contains at least one organic acid (hereinafter also referred to as "organic acid (x)") as a component other than the metal atom.

[0018] [x] Examples of the organic acid include carboxylic acids, sulfonic acids, sulfinic acids, organic phosphinic acids, organic phosphonic acids, phenols, enols, thiols, acid imides, oximes, and sulfonamides.

[0019] Examples of the carboxylic acid include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, lauric acid, 2-ethylhexanoic acid, oleic acid, acrylic acid, methacrylic acid, tiglic acid (trans-2,3-dimethylacrylic acid), stearic acid, linoleic acid, linolenic acid, arachidonic acid, salicylic acid, benzoic acid, vinylbenzoic acid, p-aminobenzoic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, gallic acid, and shikimic acid; dicarboxylic acids such as oxalic acid, malonic acid, methylmalonic acid, maleic acid, succinic acid, fumaric acid, glutaric acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, and tartaric acid; and carboxylic acids having three or more carboxy groups, such as citric acid.

[0020] The carboxylic acid is also preferably a monoester of the dicarboxylic acid. Specific examples of the monoester moiety include monoalkyl esters such as monomethyl ester, monoethyl ester, and mono-t-butyl ester; monoalkoxyalkyl esters such as monomethoxyethyl ester, monoethoxyethyl ester, and mono-t-butoxyethyl ester; and monoacyloxyalkyl esters such as mono-2-acetyloxyethyl ester, mono-2-propionyloxyethyl ester, and mono-2-acryloyloxyethyl ester.

[0021] Examples of the carboxylic acid include compounds (x1) to (x7) represented by the following structural formulas (hereinafter also referred to as "carboxylic acid (x1)").

[0022] The carboxylic acid (x1) and the carboxylic acid (x2) are compounds having an alkyl group or an ether bond. The carboxylic acid (x1) is, for example, a compound represented by the following formula:

[0023]

[0024] The carboxylic acid (x2) is, for example, a compound represented by the following formula:

[0025]

[0026] The carboxylic acid (x3) is a compound having an unsaturated hydrocarbon group, such as a compound represented by the following formula:

[0027]

[0028] The carboxylic acid (x4) is a compound having two carboxy groups (dicarboxylic acid), and is, for example, a compound represented by the following formula:

[0029]

[0030] The carboxylic acid (x5) is a compound having a carboxylic acid ester structure, such as a compound represented by the following formula:

[0031]

[0032]

[0033] The carboxylic acid (x6) and the carboxylic acid (x7) are compounds having a nitrogen atom such as an amide group or an amino group, and are, for example, compounds represented by the following formula.

[0034]

[0035]

[0036]

[0037] Examples of the sulfonic acid include benzenesulfonic acid and p-toluenesulfonic acid.

[0038] Examples of the sulfinic acid include benzenesulfinic acid and p-toluenesulfinic acid.

[0039] Examples of the organic phosphinic acid include diethylphosphinic acid, methylphenylphosphinic acid, and diphenylphosphinic acid.

[0040] Examples of the organic phosphonic acid include methylphosphonic acid, ethylphosphonic acid, t-butylphosphonic acid, cyclohexylphosphonic acid, and phenylphosphonic acid.

[0041] Examples of the phenols include monohydric phenols such as phenol, cresol, 2,6-xylenol, and naphthol; dihydric phenols such as catechol, resorcinol, hydroquinone, and 1,2-naphthalenediol; and trihydric or higher phenols such as pyrogallol and 2,3,6-naphthalenetriol.

[0042] Examples of the enol include 2-hydroxy-3-methyl-2-butene and 3-hydroxy-4-methyl-3-hexene.

[0043] Examples of the thiol include mercaptoethanol and mercaptopropanol.

[0044] Examples of the acid imide include carboxylic acid imides such as maleimide and succinimide, and sulfonic acid imides such as di(trifluoromethanesulfonic acid)imide and di(pentafluoroethanesulfonic acid)imide.

[0045] Examples of the oxime include aldoximes such as benzaldoxime and salicylaldoxime, and ketoximes such as diethylketoxime, methylethylketoxime and cyclohexanoneoxime.

[0046] Examples of the sulfonamide include methylsulfonamide, ethylsulfonamide, benzenesulfonamide, and toluenesulfonamide.

[0047] The organic acid [x] is preferably a carboxylic acid, more preferably an unsaturated carboxylic acid, and even more preferably acrylic acid, methacrylic acid, or tiglic acid.

[0048] Examples of components other than the metal atom and the organic acid (x) that may be contained in the compound (A) include hydroxy acid esters, β-diketones, α,α-dicarboxylic acid esters, and amine compounds.

[0049] Examples of the hydroxy acid ester include glycolic acid ester, lactic acid ester, 2-hydroxycyclohexane-1-carboxylic acid ester, salicylic acid ester, and the like.

[0050] Examples of the β-diketone include 2,4-pentanedione, 3-methyl-2,4-pentanedione, and 3-ethyl-2,4-pentanedione.

[0051] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0052] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0053] Examples of the amine compound include diethanolamine and triethanolamine.

[0054] The compound [A] is preferably a metal compound composed of the above metal atom and the above carboxylic acid, and more preferably a metal compound composed of magnesium, calcium, yttrium, lanthanum, cobalt, or zinc and a carboxylic acid. The form in which the organic acid [x] is contained in the compound [A] also includes an organic acid anion obtained by removing a hydrogen ion from the organic acid [x].

[0055] The compound [A] may contain one or more organic acids [x]. The compound [A] may contain one or more carboxylic acids. The compound [A] may contain an unsaturated carboxylic acid and a saturated carboxylic acid.

[0056] The lower limit of the weight-average molecular weight of the compound [A] is preferably 500, more preferably 800, and even more preferably 1000. The upper limit of the weight-average molecular weight is preferably 15,000, more preferably 12,000, and even more preferably 10,000. The lower limit of the ratio (Mw / Mn) of the weight-average molecular weight (Mw) of the compound [A] to the number-average molecular weight (Mn) is preferably 1.0, more preferably 1.1, and particularly preferably 1.2. The upper limit of Mw / Mn is preferably 5.0, more preferably 3.0, and particularly preferably 2.5. This can improve both the cleanability of the periphery of the substrate during film formation and the etching resistance of the resulting film. The method for measuring the weight-average molecular weight of the compound [A] is as described in the Examples.

[0057] The lower limit of the hydrodynamic diameter of the compound [A] measured by dynamic light scattering is preferably 1 nm, more preferably 1.2 nm, and even more preferably 1.4 nm. The upper limit of the hydrodynamic diameter is preferably 10 nm, more preferably 8 nm, and even more preferably 6 nm. This can improve both the cleanability of the periphery of the substrate during film formation and the etching resistance of the resulting film. The method for measuring the hydrodynamic diameter of the compound [A] measured by dynamic light scattering is as described in the Examples.

[0058] The film-forming composition may contain one or more types of the compound (A).

[0059] The lower limit of the content of the compound [A] relative to all components contained in the composition is preferably 0.1 mass%, more preferably 0.5 mass%, and even more preferably 1 mass%, and the upper limit of the content is preferably 15 mass%, more preferably 10 mass%, and even more preferably 5 mass%.

[0060] [Method for synthesizing compound [A]] Compound [A] can be synthesized, for example, by a method of carrying out a hydrolysis condensation reaction using a metal-containing compound (hereinafter also referred to as "metal-containing compound [b]"), a method of carrying out a ligand exchange reaction using a metal-containing compound [b], etc. Here, the "hydrolysis condensation reaction" refers to a reaction in which a hydrolyzable group in the metal-containing compound [b] is hydrolyzed to convert it to -OH, and the two resulting -OH groups undergo dehydration condensation to form -O-.

[0061] (Metal-Containing Compound [b]) The metal-containing compound [b] is a metal compound precursor (b1) having a hydrolyzable group, a hydrolyzate of the metal compound precursor (b1) having a hydrolyzable group, a hydrolysis condensate of the metal compound precursor (b1) having a hydrolyzable group, or a combination thereof. The metal compound precursor (b1) can be used alone or in combination of two or more.

[0062] Examples of the hydrolyzable group include a halogen atom, an alkoxy group, and an acyloxy group.

[0063] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0064] Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, an isobutoxy group, a t-butoxy group, and an n-pentoxy group.

[0065] Examples of the acyloxy group include an acetoxy group, a propionyloxy group, a butyryloxy group, a pivaloyl group, a t-amylcarbonyloxy group, an n-hexylcarbonyloxy group, and an n-octylcarbonyloxy group.

[0066] The hydrolyzable group is preferably an alkoxy group, more preferably an alkoxy group having 1 to 5 carbon atoms, still more preferably an alkoxy group having 1 to 4 carbon atoms, and particularly preferably a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, or a t-butoxy group.

[0067] [b] When the metal-containing compound is a hydrolysis condensate of a metal compound precursor (b1), the hydrolysis condensate of the metal compound precursor (b1) may be a hydrolysis condensate of a metal compound precursor (b1) having a hydrolyzable group and a compound containing a metalloid atom, as long as the effects of the present invention are not impaired. That is, the hydrolysis condensate of the metal compound precursor (b1) may contain a metalloid atom within a range that does not impair the effects of the present invention. Examples of the metalloid atom include silicon, boron, germanium, antimony, tellurium, etc. The content of the metalloid atom in the hydrolysis condensate of the metal compound precursor (b1) is usually less than 50 atomic % relative to the total of the metal atoms and metalloid atoms in the hydrolysis condensate. The upper limit of the content of the metalloid atom is preferably 30 atomic %, more preferably 10 atomic %, relative to the total of the metal atoms and metalloid atoms in the hydrolysis condensate.

[0068] Examples of the metal compound precursor (b1) include a compound represented by the following formula (α) (hereinafter also referred to as “compound (m)”).

[0069]

[0070] In the above formula (α), M is a metal atom. L is a ligand. a is an integer of 0 to 4. When a is 2 or more, multiple Ls may be the same or different. Y is a hydrolyzable group selected from a halogen atom, an alkoxy group, and an acyloxy group. b is an integer of 0 to 6. Multiple Ys may be the same or different, provided that a+b is 2 or more, and L is a ligand that does not correspond to Y.

[0071] Examples of the metal atom represented by M include the same metal atoms as those exemplified as the metal atoms constituting the compound (A).

[0072] The ligand represented by L may be a monodentate ligand or a polydentate ligand.

[0073] Examples of the monodentate ligand include a hydroxo ligand, a carboxy ligand, an amide ligand, and ammonia.

[0074] The amide ligand may be, for example, an unsubstituted amide ligand (NH ２ ), methylamide ligand (NHMe), dimethylamide ligand (NMe ２ ), diethylamide ligand (NEt ２ ), dipropylamide ligand (NPr ２ ) etc.

[0075] Examples of the polydentate ligand include hydroxy acid esters, β-diketones, β-ketoesters, β-dicarboxylic acid esters, hydrocarbons having a π bond, diphosphines, and acetamidinate ligands.

[0076] Examples of the hydroxy acid ester include glycolic acid ester, lactic acid ester, 2-hydroxycyclohexane-1-carboxylic acid ester, salicylic acid ester, and the like.

[0077] Examples of the β-diketone include 2,4-pentanedione, 3-methyl-2,4-pentanedione, and 3-ethyl-2,4-pentanedione.

[0078] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0079] Examples of the β-dicarboxylic acid ester include malonic acid diester, α-alkyl-substituted malonic acid diester, α-cycloalkyl-substituted malonic acid diester, and α-aryl-substituted malonic acid diester.

[0080] Examples of the hydrocarbon having a π bond include: chain olefins such as ethylene and propylene; cyclic olefins such as cyclopentene, cyclohexene and norbornene; chain dienes such as butadiene and isoprene; cyclic dienes such as cyclopentadiene, methylcyclopentadiene, pentamethylcyclopentadiene, cyclohexadiene and norbornadiene; and aromatic hydrocarbons such as benzene, toluene, xylene, hexamethylbenzene, naphthalene and indene.

[0081] Examples of the diphosphines include 1,1-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, and 1,1′-bis(diphenylphosphino)ferrocene.

[0082] Examples of the acetamidinate ligand include N,N'-dialkylacetamidinate ligands such as N,N'-dimethylacetamidinate ligand, N,N'-diethylacetamidinate ligand, N,N'-di-n-propylacetamidinate ligand, N,N'-diisopropylacetamidinate ligand, N,N'-di-n-butylacetamidinate ligand, and N,N'-di-t-butylacetamidinate ligand.

[0083] As the halogen atom, alkoxy group and acyloxy group represented by Y, the groups shown as the hydrolyzable group contained in the metal compound precursor (b1) can be suitably employed.

[0084] As b, an integer of 2 to 4 is preferred, and 2 or 3 is more preferred.

[0085] [b] The metal-containing compound is preferably a metal alkoxide that has not undergone hydrolysis or hydrolytic condensation, or a metal acyloxide that has not undergone hydrolysis or hydrolytic condensation.

[0086] [b] Examples of the metal-containing compound include magnesium (II) methoxide, magnesium (II) ethoxide, magnesium (II) n-propoxide, magnesium (II) n-butoxide, magnesium (II) isobutoxide, magnesium (II) t-butoxide, magnesium (II) n-pentoxide, magnesium (II) acetate tetrahydrate, calcium (II) methoxide, calcium (II) ethoxide, and calcium (II) n-propoxide. , calcium(II) n-butoxide, calcium(II) t-butoxide, calcium(II) n-pentoxide, strontium(II) methoxide, strontium(II) ethoxide, strontium(II) acetate, barium(II) methoxide, barium(II) ethoxide, lanthanum(III) isopropoxide, hafnium(IV) t-butoxide, yttrium(III) methoxide, yttrium(III) ethoxide, yttrium(I II) isopropoxide, yttrium(III) t-butoxide, yttrium(III) acetate tetrahydrate, zirconium(IV) t-butoxide, lanthanum(III) isopropoxide, lanthanum(III) acetate hydrate, cobalt(II) methoxide, cobalt(II) ethoxide, cobalt(II) n-propoxide, cobalt(II) isopropoxide, cobalt(II) t-butoxide, cobalt(II) n-pentoxide, zinc(II) methoxy oxide, zinc(II) ethoxide, zinc(II) propoxide, zinc(II) n-butoxide, zinc(II) t-butoxide, aluminum(III) ethoxide, aluminum(III) isopropoxide, tris(dimethylamido)aluminum(III), tris(dimethylamino)gallium(III), gallium(III) methoxide, gallium(III) ethoxide, bis(N,N'-di-t-butylacetamidinato)nickel(II), bis(N,Examples of suitable manganese compounds include manganese(II) N'-di-t-butylacetamidinato), manganese(II) methoxide, manganese(II) ethoxide, scandium(III) ethoxide, scandium(III) isopropoxide, scandium(III) acetate hydrate, indium(III) ethoxide, indium(III) isopropoxide, tetrakis(dimethylamido)tin(IV), lead(II) methoxide, lead(II) ethoxide, lead(II) n-propoxide, and cerium(III) acetate hydrate.

[0087] When the metal-containing compound [b] contains impurities, it can be purified by recrystallization, sublimation purification, distillation, chromatography, or a combination thereof to obtain a highly pure metal-containing compound [b].

[0088] The lower limit of the amount of organic acid [x] required for synthesis of compound [A] is preferably 1 mole, more preferably 2 moles, per mole of metal-containing compound [b], while the upper limit of the amount of organic acid [x] required for synthesis of compound [A] is preferably 6 moles, more preferably 4 moles, per mole of metal-containing compound [b].

[0089] During the synthesis reaction of the compound [A], in addition to the metal compound precursor (b1) and the organic acid [x], a compound capable of becoming a multidentate ligand represented by L in the compound of the above formula (α) or a compound capable of becoming a bridging ligand may be added. Examples of the compound capable of becoming a bridging ligand include compounds having multiple hydroxy groups, isocyanate groups, amino groups, ester groups, and amide groups.

[0090] As a method for carrying out a hydrolysis condensation reaction using the metal-containing compound [b], for example, a method of carrying out a hydrolysis condensation reaction of the metal-containing compound [b] in a solvent containing water can be mentioned. In this case, other compounds having hydrolyzable groups may be added as necessary. The lower limit of the amount of water used in this hydrolysis condensation reaction is preferably 0.2 times by mole, more preferably 1 time by mole, and even more preferably 3 times by mole, relative to the hydrolyzable groups of the metal-containing compound [b] or the like. The upper limit of the amount of water is preferably 20 times by mole, more preferably 15 times by mole, and even more preferably 10 times by mole.

[0091] Examples of methods for carrying out a ligand exchange reaction using a [b] metal-containing compound include mixing at least one [b] metal-containing compound and at least one [x] organic acid. In this case, mixing may be carried out in a solvent or without using a solvent. After mixing one [b] metal-containing compound and one [x] organic acid to carry out a ligand exchange reaction, one or more different [x] organic acids may be further mixed to carry out a partial ligand exchange reaction, thereby coordinating multiple [x] organic acids. In addition, a base such as triethylamine may be added to the above mixing, if necessary. The amount of the base added is, for example, 1 part by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the total amount of the [b] metal-containing compound and the [x] organic acid used.

[0092] The solvent used in the synthesis reaction of compound [A] (hereinafter also referred to as "solvent [d]") is not particularly limited, and for example, the same solvents as those exemplified as solvent [B] described below can be used. Among these, alcohol-based solvents, ether-based solvents, and ester-based solvents are preferred, with monoalcohol-based solvents, polyhydric alcohol partial ether-based solvents, and polyhydric alcohol partial ether carboxylate-based solvents being more preferred, and monoalcohol-based solvents having 1 to 5 carbon atoms, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monomethyl ether acetate being particularly preferred.

[0093] When the solvent [d] is used in the synthesis reaction of the compound [A], the solvent used may be removed after the reaction, but it may also be used as the solvent [B] for the film-forming composition without being removed after the reaction.

[0094] [Solvent (B)] The solvent (B) is not particularly limited as long as it is a solvent that can dissolve or disperse at least the compound (A) and other optional components, etc. The composition may contain one or more solvents (B).

[0095] The solvent (B) may be an organic solvent, such as an alcohol solvent, a ketone solvent, an ether solvent, an ester solvent, a nitrogen-containing solvent, or a sulfur-containing solvent.

[0096] Examples of alcohol-based solvents include monoalcohol-based solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, t-butanol, n-pentanol, and 4-methyl-2-pentanol, and polyhydric alcohol-based solvents such as ethylene glycol, 1,2-propylene glycol, triethylene glycol, and tripropylene glycol.

[0097] Examples of the ketone solvent include chain ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and 2-heptanone, and cyclic ketone solvents such as cyclohexanone.

[0098] Examples of ether solvents include chain ether solvents such as n-butyl ether, polyhydric alcohol ether solvents such as cyclic ether solvents such as tetrahydrofuran and 1,4-dioxane, and polyhydric alcohol partial ether solvents such as propylene glycol monoethyl ether, tripropylene glycol monomethyl ether, and tetraethylene glycol monomethyl ether.

[0099] Examples of ester-based solvents include carbonate-based solvents such as diethyl carbonate, acetate monoester-based solvents such as methyl acetate, ethyl acetate, and butyl acetate, lactone-based solvents such as γ-butyrolactone, polyhydric alcohol partial ether carboxylate-based solvents such as diethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate, and lactate-based solvents such as methyl lactate and ethyl lactate.

[0100] Examples of the nitrogen-containing solvent include chain nitrogen-containing solvents such as N,N-dimethylacetamide, and cyclic nitrogen-containing solvents such as N-methylpyrrolidone.

[0101] Examples of sulfur-containing solvents include chain sulfur-containing solvents such as dimethyl sulfone and dimethyl sulfoxide, and cyclic sulfur-containing solvents such as sulfolane.

[0102] Other examples include aromatic solvents such as toluene, xylene, and mesitylene.

[0103] The solvent (B) is preferably an ether-based solvent, an ester-based solvent, or a combination thereof, more preferably a polyhydric alcohol partial ether-based solvent, a polyhydric alcohol partial ether carboxylate-based solvent, or a combination thereof, and even more preferably propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, or a combination thereof.

[0104] The lower limit of the content of the solvent [B] relative to the total amount of the compound [A] and the solvent [B] is preferably 50% by mass, more preferably 60% by mass, and more preferably 70% by mass. The upper limit of the content is preferably 99.9% by mass, more preferably 99.5% by mass, and more preferably 99% by mass. By setting the content of the solvent [B] within the above range, the composition can be easily prepared and the coatability can be improved.

[0105] [Other Optional Components] The composition may contain other components in addition to those described above, such as organic acids, orthoesters, acid generators, polymer additives, polymerization inhibitors, surfactants, crosslinking agents, and basic compounds.

[0106] When the composition contains other optional components, the content of the other optional components in the composition can be appropriately determined depending on the type, function, etc. of the other optional components used.

[0107] As the organic acid, the organic acid [x] shown in the compound [A] can be suitably used.

[0108] Orthoesters are esters of orthocarboxylic acids. Orthoesters react with water to give carboxylic acid esters, etc. Examples of orthoesters include orthoformates such as methyl orthoformate, ethyl orthoformate, and propyl orthoformate; orthoacetic acid esters such as methyl orthoacetate, ethyl orthoacetate, and propyl orthoacetate; and orthopropionic acid esters such as methyl orthopropionate, ethyl orthopropionate, and propyl orthopropionate. Of these, orthoformates are preferred, and trimethyl orthoformate is more preferred.

[0109] The acid generator is a compound that generates an acid upon irradiation with radiation and / or heating. The composition may contain one or more acid generators.

[0110] Examples of the acid generator include onium salt compounds and N-sulfonyloxyimide compounds.

[0111] The composition may contain one or more polymer additives, which can improve the coatability to the substrate or the organic underlayer film and the continuity of the film.

[0112] Examples of the polymer additive include (poly)oxyalkylene polymer compounds, fluorine-containing polymer compounds, and non-fluorine-containing polymer compounds.

[0113] Examples of the (poly)oxyalkylene polymer compound include polyoxyalkylenes such as (poly)oxyethylene (poly)oxypropylene adducts; (poly)oxyalkyl ethers such as diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene-2-ethylhexyl ether, and oxyethylene oxypropylene adducts to higher alcohols having 12 to 14 carbon atoms; (poly)oxyalkylene (alkyl)aryl ethers such as polyoxypropylene phenyl ether and polyoxyethylene nonylphenyl ether; alkylene oxyalkylene aryl ethers of acetylene alcohols such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-hexyne-2,5-diol, and 3-methyl-1-butyn-3-ol; Examples of suitable acetylene ethers include acetylene ethers obtained by addition polymerization of alkyl esters; (poly)oxyalkylene fatty acid esters such as diethylene glycol oleate, diethylene glycol laurate, and ethylene glycol distearate; (poly)oxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan trioleate; (poly)oxyalkylene alkyl (aryl) ether sulfate salts such as polyoxypropylene methyl ether sodium sulfate and polyoxyethylene dodecylphenol ether sodium sulfate; (poly)oxyalkylene alkyl phosphates such as (poly)oxyethylene stearyl phosphate; and (poly)oxyalkylene alkyl amines such as polyoxyethylene laurylamine.

[0114] Examples of the fluorine-containing polymer compound include compounds containing a repeating unit derived from a (meth)acrylate compound having a fluorine atom and a repeating unit derived from a (meth)acrylate compound having two or more (preferably five or more) alkyleneoxy groups (preferably ethyleneoxy groups, propyleneoxy groups).

[0115] Examples of non-fluorine-based polymer compounds include linear or branched alkyl (meth)acrylates such as lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isooctyl (meth)acrylate, isostearyl (meth)acrylate, and isononyl (meth)acrylate; alkoxyethyl (meth)acrylates such as methoxyethyl (meth)acrylate; alkylene glycol di(meth)acrylates such as ethylene glycol di(meth)acrylate and 1,3-butylene glycol di(meth)acrylate; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; dicyclopentenyloxyethyl (meth)acrylate; and nonylphenoxy polyethylene glycol (-(CH ２ CH ２ O) ｎ -structure, n=1 to 17) (meth)acrylate and other compounds containing one or more repeating units derived from a (meth)acrylate monomer or the like.

[0116] The composition may contain one or more polymerization inhibitors, which may enhance the storage stability of the composition.

[0117] Examples of the polymerization inhibitor include hydroquinone compounds such as 4-methoxyphenol and 2,5-di-t-butylhydroquinone, and nitroso compounds such as N-nitrosophenylhydroxylamine and its aluminum salt.

[0118] The composition may contain one or more surfactants, which can improve the coatability onto a substrate or an organic underlayer film and the continuity of the film.

[0119] Commercially available surfactants include, for example, "Newcol 2320," "Newcol 714-F," "Newcol 723," "Newcol 2307," and "Newcol 2303" (all manufactured by Nippon Nyukazai Co., Ltd.), "Paionin D-1107-S", "Paionin D-1007", "Paionin D-1106-DIR", "New Kalgen TG310", "New Kalgen TG310", "Paionin D-6105-W", "Paionin D-6112", "Paionin D-6512" (all manufactured by Takemoto Oil & Fat Co., Ltd.), "Surfynol 420", "Surfynol 440", "Surfynol 465", "Surfynol 2502" (all manufactured by Nippon Air Products Co., Ltd.), "Megafac F171", "Megafac F172", "Megafac F173", "Megafac F176", "Megafac F177", "Megafac F141", "Megafac F142", "Megafac F143", "Megafac F1 Examples of such surfactants include "44", "R30", "F437", "F475", "F479", "F482", "F562", "F563", "F780", "R-40", "DS-21", "RS-56", "RS-90", and "RS-72-K" (all manufactured by DIC Corporation), "Fluorard FC430" and "Fluorard FC431" (all manufactured by Sumitomo 3M Limited), "Asahiguard AG710", "Surflon S-382", "SC-101", "SC-102", "SC-103", "SC-104", "SC-105", and "SC-106" (all manufactured by AGC Inc.), "FTX-218", and "NBX-15" (manufactured by Neos Corporation).

[0120] The type of crosslinking agent is not particularly limited, and known crosslinking agents can be freely selected and used. Preferably, at least one selected from the group consisting of polyfunctional (meth)acrylates, cyclic ether-containing compounds, glycolurils, diisocyanates, melamines, benzoguanamines, polyfunctional thiol compounds, polysulfide compounds, and sulfide compounds is used as the crosslinking agent. When the composition contains a crosslinking agent, the etching resistance of the resist underlayer film can be improved.

[0121] The basic compound accelerates the curing reaction of the composition, thereby improving the strength of the formed film. Examples of basic compounds include compounds having a basic amino group, and base generators that generate compounds having a basic amino group under the action of acid or heat. Examples of compounds having a basic amino group include amine compounds. Examples of base generators include amide group-containing compounds, urea compounds, and nitrogen-containing heterocyclic compounds. Specific examples of amine compounds, amide group-containing compounds, urea compounds, and nitrogen-containing heterocyclic compounds include the compounds described in paragraphs

[0079] to

[0082] of JP 2016-27370 A.

[0122] [Method for preparing a film-forming composition] The film-forming composition can be prepared by mixing the compound [A], the solvent [B], and, if necessary, any optional components in a predetermined ratio, and preferably filtering the resulting mixture through a membrane filter or the like having a pore size of 0.5 μm or less. In the composition, the compound [A] is preferably dissolved in the solvent [B].

[0123] [Coating Step] In the coating step, the film-forming composition is coated onto a substrate. The coating method for the film-forming composition is not particularly limited, and can be performed by any appropriate method, such as spin coating, casting coating, or roll coating. This forms a coated film, and the solvent (B) volatilizes, forming a film (metal hard mask) as a resist underlayer film.

[0124] Examples of the substrate include metal or semimetal substrates such as silicon substrates, aluminum substrates, nickel substrates, chromium substrates, molybdenum substrates, tungsten substrates, copper substrates, tantalum substrates, and titanium substrates, among which silicon substrates are preferred.The substrate may also be a substrate on which a silicon nitride film, an alumina film, a silicon dioxide film, a tantalum nitride film, a titanium nitride film, or the like is formed.

[0125] The substrate may have a pattern. Examples of the shape of the pattern include a trench pattern, a line-and-space pattern, a hole pattern, and a pillar pattern. Examples of the trench pattern and the line-and-space pattern include a pattern including a recess having a width of 5 nm to 100 nm, and a pattern including a recess having a depth of 5 nm to 500 nm. Examples of the hole pattern include a pattern including a hole having a diameter of 5 nm to 100 nm, and a pattern including a hole having a depth of 5 nm to 500 nm. Examples of the pillar pattern include a pattern including a pillar having a width of 5 nm to 100 nm, and a pattern including a pillar having a height of 5 nm to 500 nm.

[0126] The lower limit of the average thickness of the resist underlayer film formed is preferably 3 nm, more preferably 5 nm, and even more preferably 10 nm. The upper limit of the average thickness is preferably 500 nm, more preferably 200 nm, and even more preferably 100 nm. The average thickness is measured according to the method described in the Examples.

[0127] The method for producing a semiconductor substrate preferably further includes a step of heating the coating film formed in the coating step (hereinafter also referred to as a "heating step"). Heating the coating film promotes the formation of a resist underlayer film. More specifically, heating the coating film promotes the volatilization of the solvent (B).

[0128] The coating film is usually heated in air, but may be heated in a nitrogen atmosphere. The lower limit of the heating temperature is preferably 320°C, more preferably 350°C, and even more preferably 380°C. The upper limit of the temperature is preferably 600°C, more preferably 550°C, and even more preferably 500°C. The lower limit of the heating time is preferably 15 seconds, more preferably 30 seconds. The upper limit of the heating time is preferably 1,200 seconds, and more preferably 600 seconds.

[0129] [Organic Underlayer Film Forming Step] In this step, prior to the resist pattern forming step, an organic underlayer film is formed directly or indirectly on the substrate having the resist underlayer film formed in the coating step.

[0130] An example of a case where an organic underlayer film is indirectly formed on a substrate having the resist underlayer film is a case where an organic underlayer film is formed on a surface modified film of the resist underlayer film formed on the resist underlayer film.

[0131] The organic underlayer film can be formed by coating an organic underlayer film-forming composition, etc. Examples of methods for forming an organic underlayer film by coating an organic underlayer film-forming composition include a method in which the organic underlayer film-forming composition is directly or indirectly applied to a substrate having the resist underlayer film, and the resulting coating film is heated or exposed to light to cure it. Examples of the organic underlayer film-forming composition that can be used include "HM8006" manufactured by JSR Corporation. The heating and exposure conditions can be appropriately determined depending on the type of organic underlayer film-forming composition used, etc.

[0132] [Silicon-containing film forming step] In this step, prior to the resist pattern forming step, a silicon-containing film is formed directly or indirectly on the substrate having the resist underlayer film formed in the coating step.

[0133] Examples of cases in which a silicon-containing film is indirectly formed on a substrate having the resist underlayer film include cases in which a surface-modified film of the resist underlayer film or the organic underlayer film is formed on the resist underlayer film.

[0134] The silicon-containing film can be formed by coating a silicon-containing film-forming composition, chemical vapor deposition (CVD), atomic layer deposition (ALD), or the like. Examples of methods for forming a silicon-containing film by coating a silicon-containing film-forming composition include a method in which the silicon-containing film-forming composition is directly or indirectly applied to the resist underlayer film, and the resulting coating film is then cured by exposure and / or heating. Examples of commercially available silicon-containing film-forming compositions include "NFC SOG01," "NFC SOG04," and "NFC SOG080" (all manufactured by JSR Corporation). Silicon oxide films, silicon nitride films, silicon oxynitride films, and amorphous silicon films can be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0135] [Cleaning Step] In this step, after the coating step and before the resist pattern forming step, the peripheral edge of the substrate is washed with a cleaning liquid. As the cleaning liquid, the organic solvents exemplified as the solvent [B] can be used. The cleaning liquid may contain an acid. As the acid, the acids exemplified as the organic acid [x] are preferred.

[0136] The cleaning method is not particularly limited, and known methods can be employed. Typically, a substrate on which various films have been formed is first rotated at a predetermined speed. Next, while a cleaning liquid is being discharged from the cleaning liquid discharge nozzle, the cleaning liquid discharge nozzle is moved at a predetermined speed from the outer peripheral edge of the rotating substrate toward the center of the substrate. The cleaning liquid discharge nozzle stops moving after moving a predetermined distance, and the cleaning liquid is further discharged for a predetermined period of time. Thereafter, the discharge of the cleaning liquid from the cleaning liquid discharge nozzle is stopped, and the cleaning is completed by drying as necessary. The rotation speed of the substrate, the amount of cleaning liquid discharged per unit time, the moving speed and moving distance of the cleaning liquid discharge nozzle, the cleaning liquid discharge time after the movement of the cleaning liquid discharge nozzle is stopped, and the like can be appropriately set depending on the substrate size, the number, type, and thickness of the formed films, the cleaning area, and the like.

[0137] After the film-forming composition is applied to the substrate, the cleaning step can be carried out with or without the heating step. When the cleaning step is carried out without the heating step after the application step, it is preferable to carry out the heating step after the cleaning step.

[0138] [Resist Pattern Forming Step] In this step, a resist pattern is formed directly or indirectly on the resist underlayer film. Methods for performing this step include, for example, a method using a resist composition, a method using a nanoimprinting method, a method using a self-assembling composition, etc. Examples of the case where a resist pattern is indirectly formed on the resist underlayer film include, for example, a case where a resist pattern is formed on the silicon-containing film when the semiconductor substrate manufacturing method includes the silicon-containing film forming step.

[0139] Specifically, in the method using the resist composition, the resist composition is applied so that the resist film to be formed has a predetermined thickness, and then the applied film is pre-baked to volatilize the solvent in the applied film, thereby forming a resist film.

[0140] Examples of the resist composition include positive or negative chemically amplified resist compositions containing a radiation-sensitive acid generator, positive resist compositions containing an alkali-soluble resin and a quinone diazide-based photosensitizer, negative resist compositions containing an alkali-soluble resin and a crosslinker, metal-containing resist compositions containing a metal such as tin, zirconium, or hafnium, etc. In this step, commercially available resist compositions can also be used as they are.

[0141] Next, the resist film formed as above is exposed by selective irradiation with radiation. The radiation used for exposure can be appropriately selected depending on the type of radiation-sensitive acid generator used in the resist composition, and examples thereof include visible light, ultraviolet light, far ultraviolet light, electromagnetic waves such as X-rays and gamma rays, electron beams, molecular beams, particle beams such as ion beams, etc. Among these, far ultraviolet light is preferred, and KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F ２ Excimer laser light (wavelength 157 nm), Kr２ Excimer laser light (wavelength 147 nm), ArKr excimer laser light (wavelength 134 nm) or extreme ultraviolet light (wavelength 13.5 nm or the like, hereinafter also referred to as "EUV") is more preferred, and KrF excimer laser light, ArF excimer laser light or EUV is even more preferred.

[0142] After the exposure, post-baking can be carried out to improve resolution, pattern profile, developability, etc. The temperature and time of this post-baking can be appropriately determined depending on the type of resist composition used, etc.

[0143] Next, the exposed resist film is developed with a developer to form a resist pattern. This development may be alkaline development or organic solvent development. In the case of alkaline development, examples of the developer include basic aqueous solutions of ammonia, triethanolamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, etc. These basic aqueous solutions may also contain an appropriate amount of a water-soluble organic solvent, such as an alcohol, e.g., methanol or ethanol, a surfactant, etc. In the case of organic solvent development, examples of the developer include the various organic solvents exemplified as the solvent [B] of the composition described above.

[0144] After development with the developer, the resist is washed and dried to form a desired resist pattern.

[0145] [Etching Step] In this step, a pattern is formed on the resist underlayer film by etching using the resist pattern as a mask. The etching may be performed once or multiple times, i.e., sequentially using the pattern obtained by etching as a mask. However, from the viewpoint of obtaining a pattern with a better shape, multiple times is preferred. When performing multiple etchings, etching is performed sequentially in the order of the silicon-containing film, the organic underlayer film, the resist underlayer film, and the substrate. Examples of etching methods include dry etching and wet etching. Among these, dry etching is preferred from the viewpoint of obtaining a better pattern shape on the substrate. For example, a gas plasma such as oxygen plasma is used for this dry etching. A semiconductor substrate having a predetermined pattern is obtained by the above etching.

[0146] Dry etching can be performed using, for example, a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected depending on the mask pattern, the elemental composition of the film to be etched, etc., and for example, CHF ３ , C.F. ４ , C ２ F ６ , C ３ F ８ , SF ６ Fluorine-based gases such as Cl ２ , BCl ３ Chlorine gases such as O ２ , O ３ , H ２ Oxygen-based gases such as O, H ２ , N.H. ３ , CO, CO ２ , C.H. ４ , C ２ H ２ , C ２ H ４ , C ２ H ６ , C ３ H ４ , C ３ H ６ , C ３ H ８ , HF, HI, HBr, HCl, NO, BCl ３reducing gases such as He, N ２ Inert gases such as Ar and the like can be used. These gases can also be used in combination. When etching a substrate using the pattern of the resist underlayer film as a mask, a fluorine-based gas is usually used.

[0147] The film-forming composition contains a compound [A] and a solvent [B]. As the film-forming composition, the film-forming composition used in the method for producing a semiconductor substrate can be suitably used.

[0148] Examples will be described below. Note that the examples shown below are representative examples of the present invention, and should not be construed as narrowing the scope of the present invention.

[0149] In the present examples, the concentrations of components other than the solvent in the mixture containing the compound (A), the weight average molecular weight, the hydrodynamic diameter determined by dynamic light scattering, and the average thickness of the film were measured by the following methods.

[0150] [Concentration of Components Other Than Solvent in Mixture Containing Compound [A]] 0.5 g of the mixture containing compound [A] was baked at 250°C for 30 minutes, and the mass of the residue was measured. The mass of this residue was divided by the mass of the mixture containing compound [A] to calculate the concentration (mass%) of the components other than the solvent in the mixture containing compound [A].

[0151] [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) were measured by gel permeation chromatography (detector: differential refractometer) using GPC columns (two "AWM-H," one "AW-H," and two "AW2500" columns, all manufactured by Tosoh Corporation) with monodisperse polystyrene as the standard under the following analytical conditions: flow rate: 0.3 mL / min, elution solvent: N,N-dimethylacetamide supplemented with LiBr (30 mM) and citric acid (30 mM), and column temperature: 40°C.

[0152] [Hydrodynamic diameter measured by dynamic light scattering] The hydrodynamic diameter was measured by obtaining the particle size distribution of the compound [A] diluted in a solvent using a multi-analyte nanoparticle diameter measurement system ("nanoSAQLA" manufactured by Otsuka Electronics Co., Ltd.) and measuring the average diameter (D ５０ ) was taken as the hydrodynamic diameter.

[0153] [Average Film Thickness] The average film thickness was determined by measuring the film thickness at nine arbitrary positions at 5 cm intervals, including the center of the film formed on the silicon wafer, using a spectroscopic ellipsometer (J.A. WOOLLAM's "M2000D"), and calculating the average value of the film thicknesses.

[0154] <Synthesis of Compound [A]> The compound [m], organic acid [x], solvent [d], and solvent [B] used in the synthesis of compound [A] are shown below. In the synthesis examples below, unless otherwise specified, "parts by mass" refers to a value when the mass of the compound [m] used is taken as 100 parts by mass. Furthermore, "molar ratio" refers to a value when the amount of substance of the compound [m] used is taken as 1. The concentrations (% by mass) of components other than the solvent in mixtures containing compound [A] are also shown in Tables 1-1 to 1-4.

[0155] The following compounds were used as the [m] compound: m-1: magnesium(II) methoxide m-2: magnesium(II) ethoxide m-3: magnesium(II) n-propoxide m-4: magnesium(II) n-butoxide m-5: magnesium(II) t-butoxide m-6: magnesium(II) n-pentoxide m-7: calcium(II) methoxide m-8: calcium(II) ethoxide m-9: calcium(II) n-propoxide m-10: calcium(II) n-butoxide m-11: calcium(II) t-butoxide m-12: calcium(II) n-pentoxide m-13: strontium(II) ethoxide m-14: barium(II) methoxide m-15: yttrium(III) methoxide m-16: yttrium(III) ethoxide m-17: Yttrium(III) isopropoxide m-18: Yttrium(III) t-butoxide m-19: Cobalt(II) methoxide m-20: Cobalt(II) n-propoxide m-21: Cobalt(II) isopropoxide m-22: Cobalt(II) n-pentoxide m-23: Zinc(II) methoxide m-24: Zinc(II) ethoxide m-25: Zinc(II) propoxide m-26: Zinc(II) n-butoxide m-27: Zinc(II) t-butoxide m-28: Aluminum(III) ethoxide m-29: Aluminum(III) isopropoxide m-30: Tris(dimethylamido)aluminum(III) m-31: Tris(dimethylamino)gallium(III) m-32: bis(N,N'-di-t-butylacetamidinato)nickel(II) m-33: bis(N,N'-di-t-butylacetamidinato)manganese(II) m-34: Scandium(III) isopropoxide m-35: Indium(III) isopropoxide m-36: Lead(II) ethoxide m-37: Lead(II) n-propoxide m-38: Magnesium(II) acetate tetrahydrate m-39: Lanthanum(III) acetate hydrate m-40: Lanthanum(III) isopropoxide m-41: Yttrium(III) acetate tetrahydrate m-42: Tetrakis(dimethylamido)tin(IV) m-43: Strontium(II) acetate m-44: Scandium(III) acetate hydrate m-45: Cerium(III) acetate hydrate m-46: Hafnium(IV) t-butoxide m-47: lanthanum (III) isopropoxide m-48: zirconium (IV) t-butoxide

[0156] As the organic acid [x], the following organic acids (x1-1) to (x1-15), organic acids (x2-1) to (x2-8), organic acids (x3-1) to (x3-3), organic acid (x3-5), organic acid (x4-1), organic acid (x5-1), organic acid (x6-15), and organic acids (x7-1) to (x7-7) were used.

[0157] x1-1: acetic acid (compound represented by the following formula (x1-1)) x1-2: acrylic acid (compound represented by the following formula (x1-2)) x1-3: methacrylic acid (compound represented by the following formula (x1-3)) x1-4: propionic acid (compound represented by the following formula (x1-4)) x1-5: tiglic acid (compound represented by the following formula (x1-5)) x1-6: vinylbenzoic acid (compound represented by the following formula (x1-6)) x1-7: oxalic acid (compound represented by the following formula (x1-7)) x1-8: glutaric acid (compound represented by the following formula (x1-8)) x1-9: terephthalic acid (compound represented by the following formula (x1-9)) x1-10: succinic acid mono-tert-butyl ester (compound represented by the following formula (x1-10)) x1-11: adipic acid monoethyl ester (compound represented by the following formula (x1-11)) x1-12: glutaric acid monoethyl ester (compound represented by the following formula (x1-12)) x1-13: succinic acid mono(2-acryloyloxyethyl) ester (compound represented by the following formula (x1-13)) x1-14: lauric acid (compound represented by the following formula (x1-14)) x1-15: malonic acid monoethyl ester (compound represented by the following formula (x1-15))

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

[0164]

[0165] [d] The following compounds were used as solvents: d-1: methanol, d-2: ethanol, d-3: n-propanol, d-4: isopropanol, d-5: n-butanol, d-6: tert-butanol, d-7: n-pentanol, d-8: propylene glycol monomethyl ether, and d-9: propylene glycol monoethyl ether.

[0166] [B] The following compounds were used as the solvent: B-1: Propylene glycol monomethyl ether B-2: Propylene glycol monoethyl ether B-3: Propylene glycol monopropyl ether B-4: Propylene glycol monomethyl ether acetate

[0167] Synthesis Example 1-1 (Synthesis of [A] Compound (A-1)) Compound (m-1) (molar ratio 1) and solvent (d-1) (40 parts by mass) were placed in a reaction vessel under a nitrogen atmosphere. Compound (x-1) (molar ratio 2) was added dropwise to the reaction vessel over 20 minutes while stirring at room temperature (25°C to 30°C). Next, the reaction was carried out at 50°C for 3 hours. After completion of the reaction, the reaction vessel was cooled to 30°C or below. The precipitate obtained by cooling was filtered, washed with methanol (100 parts by mass), and then vacuum dried to obtain compound (A-1). Compound (A-1) had an Mw of 2,400, an Mw / Mn of 1.2, and a hydrodynamic diameter of 3.0 nm.

[0168] [Synthesis Examples 1-2 to 1-14, 1-23 to 1-31, 1-36 to 1-57, and 1-73 to 1-78] (Synthesis of [A] Compounds (A-2) to (A-14), (A-23) to (A-31), (A-36) to (A-57), and (A-73) to (A-78)) [A] Compounds (A-2) to (A-14), (A-23) to (A-31), (A-36) to (A-57), and (A-73) to (A-78) were obtained in the same manner as in Synthesis Example 1-1, except that the types and amounts of [m] compound, [x] organic acid, and [d] solvent shown in Tables 1-1 and 1-2 below were used. The Mw, Mw / Mn, and hydrodynamic diameters of the [A] compounds are shown in Tables 1-1 to 1-4 below, along with those of the other Synthesis Examples below. In Table 1 below, "-" indicates that the corresponding component was not used. The same applies below.

[0169] Synthesis Example 1-15 (Synthesis of [A] Compound (A-15)) Under a nitrogen atmosphere, compound (m-15) (molar ratio 1) and solvent (d-1) (40 parts by mass) were placed in a reaction vessel. Compound (x-10) (molar ratio 3) was added dropwise to the reaction vessel over 20 minutes while stirring at room temperature (25°C to 30°C). The reaction was then carried out at 80°C for 2 hours. After completion of the reaction, the reaction vessel was cooled to 30°C or below. To the cooled reaction solution, 1,000 parts by mass of solvent (B-1) was added, and n-propanol, the alcohol produced by the reaction, and excess solvent (B-1) were removed using an evaporator to obtain a mixture containing compound (A-15). The concentration of components other than the solvent in the mixture containing compound (A-15) was 20% by mass. The compound (A-15) had an Mw of 5,500, an Mw / Mn of 1.3, and a hydrodynamic diameter of 5.5 nm.

[0170] [Synthesis Examples 1-16 to 1-22, 1-32 to 1-35, 1-58 to 1-72, and 1-79 to 1-138] (Synthesis of [A] compounds (A-16) to (A-22), (A-32) to (A-35), (A-58) to (A-72), and (A-79) to (A-138)) [A] compounds (A-16) to (A-22), (A-32) to (A-35), (A-58) to (A-72), and (A-79) to (A-138) were obtained in the same manner as in Synthesis Example 1-15, except that the types and amounts of [m] compound, [x] organic acid, [d] solvent, and [B] solvent shown in Tables 1-1 to 1-4 below were used.

[0171] Synthesis Example 1-139 (Synthesis of [A] Compound (A-139)) Under a nitrogen atmosphere, compound (m-38) (molar ratio 1), compound (x7-1) (molar ratio 2), and solvent (d-1) (100 parts by mass) were charged into a reaction vessel. Then, the mixture was stirred at 60°C for 1 hour. After the reaction was completed, the reaction vessel was cooled to 30°C or below. To the cooled reaction solution, 900 parts by mass of solvent (B-1) were added, and then the solvent (d-1), the carboxylic acid produced by the reaction, and excess solvent (B-1) were removed using an evaporator to obtain a mixture containing compound (A-139). The concentration of components other than the solvent in the mixture containing compound (A-1) [A] was 20% by mass.

[0172] [Synthesis of Synthesis Examples 1-140 to 1-165] [A] Compounds (A-140) to (A-165) were obtained in the same manner as in Synthesis Example 1-1, except that the types and amounts of the [m] compounds, [x] organic acids, and [d] solvents shown in Table 1-5 below were used.

[0173] Comparative Synthesis Example 1-1 (Synthesis of Compound (a-1)) Tetraisopropoxytitanium(IV) (molar ratio 1), acrylic acid (molar ratio 2), and solvent (d-1) (100 parts by mass) were charged into a reaction vessel under a nitrogen atmosphere. Then, a reaction was carried out at 60°C for 1 hour with stirring. After completion of the reaction, the reaction vessel was cooled to 30°C or below. 900 parts by mass of solvent (B-1) was added to the cooled reaction solution, and then solvent (d-1), the carboxylic acid produced by the reaction, and excess solvent (B-1) were removed using an evaporator to obtain a mixture containing compound (a-1). The concentration of components other than the solvent in the mixture containing compound (a-1) was 20% by mass.

[0174]

[0175]

[0176]

[0177]

[0178]

[0179] <Preparation of Composition> [A] Compound, [B] Solvent, and [D] Other Additives used in the preparation of the composition are shown below.

[0180] The compounds (A-1) to (A-165) synthesized above were used as the compound [A]. The compound (a-1) synthesized above was used as the comparative compound.

[0181] As the solvent [B], the solvents (B-1) to (B-4) used in the synthesis of the compound [A] were used.

[0182] [D] As other additives, the following compounds were used.

[0183] D-1: Acrylic acid (compound represented by the following formula (D-1)) D-2: Methacrylic acid (compound represented by the following formula (D-2)) D-3: Trimethyl orthoformate (compound represented by the following formula (D-3)) D-4: "NBX-15" from Neos Co., Ltd. (compound represented by the following formula (D-4)) D-5: Compound represented by the following formula (D-5) D-6: Compound represented by the following formula (D-6) D-7: Compound represented by the following formula (D-7) D-8: Surfactant ("DOWSIL SH28 Paint Additive" from Dow Toray Industries, Inc.)

[0184]

[0185] [Example 1-1] Preparation of Composition (J-1) As shown in Table 2-1 below, 3.00 parts by mass of [A] compound (A-1) and 97.000 parts by mass of [B] solvent (B-1) were mixed. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) filter with a pore size of 0.2 μm to prepare composition (J-1). In Table 2 below, "-" indicates that the corresponding component was not used. The same applies hereinafter.

[0186] Examples 1-2 to 1-182 Preparation of Compositions (J-2) to (J-182) Compositions (J-2) to (J-182) were prepared in the same manner as in Example 1-1, except that the types and contents of each component were as shown in Tables 2-1 to 2-4 below.

[0187] [Comparative Example 1-1] Preparation of Composition (j-1) 3.00 parts by mass of Compound (a-1) and 97.000 parts by mass of (B-1) as a solvent [B] were mixed. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) filter with a pore size of 0.2 μm to prepare Composition (j-1).

[0188]

[0189]

[0190]

[0191]

[0192] <Evaluation> The metal cleaning properties and etching resistance of each of the compositions prepared above were evaluated according to the following methods. The evaluation results are shown in Tables 3-1 to 3-5 and 4-1 to 4-5 below.

[0193] [Metal Cleaning Property] The following compounds were used as the cleaning solution [K] for evaluating metal cleaning property: K-1: Propylene glycol monomethyl ether K-2: Propylene glycol monoethyl ether K-3: Propylene glycol monomethyl ether acetate

[0194] Each of the compositions prepared above was applied to a silicon wafer (substrate) by a spin coater (Tokyo Electron Limited's "CLEAN TRACK ACT8") using a rotary coating method. While rotating at 1,500 rpm, the cleaning solution ejection nozzle was moved at a speed of 1 mm per second to a position 2 mm from the outer edge of the substrate to the center of the substrate, and the [K] cleaning solution was ejected at a rate of 2 ml per second. The cleaning solution was then ejected at a rate of 2 ml per second for 10 seconds at a position 2 mm from the outer edge of the substrate to the center of the substrate, and the substrate was then rotated at 1,500 rpm for 30 seconds. Next, the substrate was heated at 450°C for 60 seconds to obtain an evaluation substrate A with a resist underlayer film having an average thickness of 30 nm. The outermost surface of the peripheral portion (front and back surface regions 0.3 mm from the edge) of the obtained evaluation substrate A was measured by total reflection X-ray fluorescence analysis (TXRF) (manufactured by Rigaku Corporation, "Desktop Total Reflection X-ray Fluorescence Analyzer NANOHUNTER II") to measure the peak intensity of metal atoms derived from the film.

[0195] The metal cleaning ability was evaluated as "A" when the peak intensity of the metal constituting the [A] compound detected from the evaluation substrate A was less than 10% of the peak intensity of Si, and as "B" when it was 10% or more.

[0196]

[0197]

[0198]

[0199]

[0200]

[0201] [Etching Resistance] The composition prepared above was applied onto a silicon wafer (substrate) by a spin coating method using a spin coater ("LITHIUS Pro Z" manufactured by Tokyo Electron Ltd.) The wafer was then heated at 400°C for 60 seconds in an air atmosphere, and then cooled at 23°C for 60 seconds, thereby obtaining a substrate with a film (metal oxide film) having an average thickness of 90 nm.

[0202] The film on the substrate with the film was removed by etching using an etching device (Tokyo Electron Ltd.'s "TACTRAS"). ４ The etching rate (nm / min) was calculated from the average thickness of the film before and after the treatment under the conditions of: / Ar = 110 / 440 sccm, PRESS. = 30 MT, HF RF (high frequency power for plasma generation) = 500 W, LF RF (high frequency power for bias) = ​​3000 W, DCS = -150 V, RDC (gas center flow ratio) = 50%, and 30 seconds. Next, the etching rate was calculated based on the etching rate of Comparative Example 3-1, and the ratio to Comparative Example 3-1 was used as a measure of etching resistance. The etching resistance was evaluated as "A" (good) when the ratio was less than 1.00, and as "B" (poor) when the ratio was 1.00 or more. Note that "-" in Table 4-4 below indicates that this is the evaluation standard for etching resistance.

[0203]

[0204]

[0205]

[0206]

[0207]

[0208] As can be seen from the results in Tables 3-1 to 3-5 and Tables 4-1 to 4-5, the compositions of the examples and the films formed from the compositions were superior in cleaning properties and etching resistance compared to the comparative examples.

[0209] According to the method for producing a semiconductor substrate of the present invention, the cleaning property of the peripheral portion of the substrate during film formation is excellent, and the etching resistance of the film is excellent, so that a well-patterned semiconductor substrate can be efficiently obtained. According to the film-forming composition of the present invention, the cleaning property of the peripheral portion of the substrate during film formation is excellent, and a film having good etching resistance can be formed. Therefore, these compositions can be suitably used in the production of semiconductor devices, which are expected to become even more miniaturized in the future.

Claims

1. A method for manufacturing a semiconductor substrate, comprising: a step of applying a film-forming composition to a substrate; wherein the film-forming composition contains a metal compound composed of at least one metal atom and at least one organic acid; and a solvent; and the metal atom is a metal atom having a boiling point of 700°C or higher when in the form of a metal fluoride.

2. The method for producing a semiconductor substrate according to claim 1, wherein the metal atoms are metal atoms whose boiling point is 990° C. or higher when in the form of a metal fluoride.

3. The method for producing a semiconductor substrate according to claim 1, wherein the weight average molecular weight of the metal compound is 500 or more and 10,000 or less.

4. The method for producing a semiconductor substrate according to claim 1, wherein the hydrodynamic diameter of said metal compound measured by dynamic light scattering is 1 nm or more and 10 nm or less.

5. The method for producing a semiconductor substrate according to claim 1, wherein the metal atom is at least one selected from the group consisting of magnesium, calcium, strontium, barium, scandium, yttrium, manganese, cobalt, nickel, zinc, aluminum, gallium, indium, tin, lead, and lanthanoids.

6. The method for producing a semiconductor substrate according to claim 1, wherein the organic acid is a carboxylic acid.

7. A film-forming composition comprising: a metal compound composed of at least one metal atom and at least one organic acid; and a solvent, wherein the metal atom is a metal atom having a boiling point of 700°C or higher when in the form of a metal fluoride.

8. The film-forming composition according to claim 7, wherein the metal atom is a metal atom whose boiling point in the form of a metal fluoride is 990° C. or higher.

9. The film-forming composition according to claim 7, wherein the weight-average molecular weight of the metal compound is 500 or more and 10,000 or less.

10. The film-forming composition according to claim 7, wherein the hydrodynamic diameter of the metal compound measured by dynamic light scattering is 1 nm or more and 10 nm or less.

11. The film-forming composition according to claim 7, wherein the metal atom is at least one selected from the group consisting of magnesium, calcium, strontium, barium, scandium, yttrium, manganese, cobalt, nickel, zinc, aluminum, gallium, indium, tin, lead, and lanthanoids.

12. The film-forming composition according to claim 7, wherein the organic acid is a carboxylic acid.

13. The film-forming composition according to claim 7, wherein the metal compound is a metal acyloxide, and the film-forming composition further contains a dicarboxylic acid.

Images