Method for producing semiconductor substrate, method for forming resist underlayer film, and cleaning fluid

Abstract

Provided are: a method for producing a semiconductor substrate using a cleaning fluid excellent in terms of the property of cleaning peripheral portions of substrates and waste-liquid stability; a method for forming a resist underlayer film; and the cleaning fluid. This method for producing a semiconductor substrate comprises: a step in which a composition for resist underlayer film formation is applied directly or indirectly to a substrate; a step in which peripheral portions of the substrate are cleaned with a cleaning fluid; and a step in which after the cleaning step, a resist pattern is formed directly on or indirectly over the resist underlayer film formed in the application step. The composition for resist underlayer film formation includes a metal compound and a solvent, and the cleaning fluid includes an organic acid.

Description

Semiconductor substrate manufacturing method, resist underlayer film forming method, and cleaning solution

[0001] The present invention relates to a method for manufacturing a semiconductor substrate, a method for forming a resist underlayer film, and a cleaning solution.

[0002] In the manufacture of semiconductor substrates and the like, a metal hard mask composition serving as a resist underlayer film has been proposed (see JP 2013-185155 A). For example, a CleanTrack (manufactured by Tokyo Electron Limited) 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, followed by cleaning with a cleaning solution to remove the coating from the edge (periphery) of the substrate. This device automatically transports the substrate, but EBR must be performed to avoid contaminating the tweezers holding the substrate. If the substrate edge cannot be cleaned by EBR, the tweezers may become contaminated, causing defects and potentially reducing device yield. When manufacturing semiconductor substrates and the like, it is generally required to be able to clean the substrate edge by EBR. As a cleaning liquid used in EBR, a mixed liquid of propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether (30:70, mass ratio) is widely used in the EBR process of resist films, silicon-containing films, and organic underlayer films.

[0003] Japanese Patent Application Laid-Open No. 2013-185155

[0004] Cleaning solutions are required to have cleaning properties that allow them to remove metal hard masks from the periphery of substrates, etc. Furthermore, when multilayer resist processes are performed in a single device, wastewater from multiple processes is often discharged through the same pipes, so cleaning solutions are required to have wastewater stability that prevents unintended events such as metal deposition in the pipes due to interference with other wastewater.

[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 manufacturing a semiconductor substrate using a cleaning liquid that is excellent in cleaning properties for the peripheral edge of the substrate and in drainage stability, a method for forming a resist underlayer film, and a cleaning liquid.

[0006] In one embodiment, the present invention relates to a method for producing a semiconductor substrate, comprising: a step of applying, directly or indirectly, a composition for forming a resist underlayer film onto a substrate; a step of cleaning a peripheral portion of the substrate with a cleaning liquid; and a step of, after the cleaning step, directly or indirectly forming a resist pattern on the resist underlayer film formed by the coating step, wherein the composition for forming a resist underlayer film contains a metal compound (hereinafter also referred to as "compound [A]") and a solvent (hereinafter also referred to as "solvent [B]"), and the cleaning liquid contains an organic acid (hereinafter also referred to as "organic acid [E]").

[0007] In another embodiment, the present invention relates to a method for forming a resist underlayer film, comprising: a step of applying a composition for forming a resist underlayer film directly or indirectly to a substrate; and a step of cleaning a peripheral edge of the substrate with a cleaning liquid, wherein the composition for forming a resist underlayer film contains a metal compound and a solvent, and the cleaning liquid contains an organic acid.

[0008] In still another embodiment, the present invention relates to a cleaning liquid used in a method for producing a semiconductor substrate, the method including the steps of: applying a composition for forming a resist underlayer film directly or indirectly to a substrate; and cleaning a peripheral portion of the substrate with a cleaning liquid, wherein the composition for forming a resist underlayer film contains a metal compound and a solvent; and the cleaning liquid contains an organic acid.

[0009] The semiconductor substrate manufacturing method uses a cleaning liquid having excellent cleaning properties and drainage stability to clean the peripheral portion of the substrate, thereby enabling efficient production of high-quality semiconductor substrates. The resist underlayer film formation method uses a cleaning liquid having excellent cleaning properties and drainage stability to efficiently form a desired resist underlayer film. The cleaning liquid has excellent cleaning properties and drainage stability. Therefore, these methods can be suitably used in the manufacture of semiconductor devices, which are expected to become even more miniaturized in the future.

[0010] The method for manufacturing a semiconductor substrate, the method for forming a resist underlayer film, and the cleaning solution according to each embodiment of the present invention will be described in detail below. Combinations of preferred embodiments are also preferred.

[0011] <<Method for Producing a Semiconductor Substrate>> The method for producing a semiconductor substrate includes a step of directly or indirectly applying a resist underlayer film-forming composition (hereinafter also referred to as "composition") to a substrate (hereinafter also referred to as "coating step"), a step of cleaning the peripheral portion of the substrate with a cleaning liquid (hereinafter also referred to as "cleaning step"), and a step of directly or indirectly forming a resist pattern on the resist underlayer film formed in the coating step after the cleaning step (hereinafter also referred to as "resist pattern forming step"). Preferably, the method for producing a semiconductor substrate further includes a step of forming a pattern in the resist underlayer film by etching using the resist pattern as a mask (hereinafter also referred to as "etching step").

[0012] The peripheral edge of the substrate refers to, for example, a peripheral portion of the substrate whose length from the outer edge to the center of the substrate is within 3.0 cm, and 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.

[0013] 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.

[0014] 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.

[0015] Hereinafter, the resist underlayer film-forming composition and cleaning solution used in the method for producing a semiconductor substrate, as well as each step in the optional organic underlayer film-forming step and silicon-containing film-forming step, will be described.

[0016] <Composition for forming resist underlayer film> 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.

[0017] [Compound [A]] The compound [A] refers to a compound containing a metal atom and an oxygen atom. Examples of the metal atom constituting the compound [A] include metal atoms of Groups 3 to 16 of the periodic table (excluding silicon atoms). The compound [A] may contain one or more types of metal atoms.

[0018] Examples of Group 3 metal atoms include scandium, yttrium, lanthanum, and cerium; examples of Group 4 metal atoms include titanium, zirconium, and hafnium; examples of Group 5 metal atoms include vanadium, niobium, and tantalum; examples of Group 6 metal atoms include chromium, molybdenum, and tungsten; examples of Group 7 metal atoms include manganese and rhenium; examples of Group 8 metal atoms include iron, ruthenium, and osmium; examples of Group 9 metal atoms include cobalt, rhodium, and iridium; examples of Group 10 metal atoms include nickel, palladium, and platinum; examples of Group 11 metal atoms include copper, silver, and gold; examples of Group 12 metal atoms include zinc, cadmium, and mercury; examples of Group 13 metal atoms include aluminum, gallium, and indium; and examples of Group 14 metal atoms include germanium, tin, and lead. Examples of metal atoms in Group 15 include antimony and bismuth, and examples of metal atoms in Group 16 include tellurium.

[0019] The metal atoms constituting the compound [A] are preferably metal atoms of Groups 3 to 16, more preferably metal atoms of Groups 4 to 14, even more preferably metal atoms of Groups 4, 5, and 14, and particularly preferably metal atoms of Group 4. Specifically, titanium, zirconium, hafnium, tantalum, tungsten, tin, or a combination thereof is more preferred.

[0020] The components other than the metal atom constituting the compound [A] (hereinafter also referred to as "compound [x]") are preferably organic acids (hereinafter also referred to as "organic acids [a]"), hydroxy acid esters, β-diketones, α,α-dicarboxylic acid esters, and amine compounds. Here, "organic acids" refer to organic compounds that exhibit acidity, and "organic compounds" refer to compounds having at least one carbon atom.

[0021] [a] 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.

[0022] 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, 2-ethylhexanoic acid, oleic acid, acrylic acid, methacrylic acid, trans-2,3-dimethylacrylic acid, stearic acid, linoleic acid, linolenic acid, arachidonic acid, salicylic acid, benzoic 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, maleic acid, methylmalonic acid, fumaric acid, adipic acid, sebacic acid, phthalic acid, and tartaric acid; and carboxylic acids having three or more carboxy groups, such as citric acid.

[0023] Examples of the sulfonic acid include benzenesulfonic acid and p-toluenesulfonic acid.

[0024] Examples of the sulfinic acid include benzenesulfinic acid and p-toluenesulfinic acid.

[0025] Examples of the organic phosphinic acid include diethylphosphinic acid, methylphenylphosphinic acid, and diphenylphosphinic acid.

[0026] Examples of the organic phosphonic acid include methylphosphonic acid, ethylphosphonic acid, t-butylphosphonic acid, cyclohexylphosphonic acid, and phenylphosphonic acid.

[0027] 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.

[0028] Examples of the enol include 2-hydroxy-3-methyl-2-butene and 3-hydroxy-4-methyl-3-hexene.

[0029] Examples of the thiol include mercaptoethanol and mercaptopropanol.

[0030] 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.

[0031] Examples of the oxime include aldoximes such as benzaldoxime and salicylaldoxime, and ketoximes such as diethylketoxime, methylethylketoxime and cyclohexanoneoxime.

[0032] Examples of the sulfonamide include methylsulfonamide, ethylsulfonamide, benzenesulfonamide, and toluenesulfonamide.

[0033] The organic acid (a) is preferably a carboxylic acid, more preferably a monocarboxylic acid, and even more preferably methacrylic acid or benzoic acid.

[0034] 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.

[0035] Examples of the β-diketone include 2,4-pentanedione, 3-methyl-2,4-pentanedione, and 3-ethyl-2,4-pentanedione.

[0036] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0037] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0038] Examples of the amine compound include diethanolamine and triethanolamine.

[0039] The compound [A] is preferably a metal compound constituted by a metal atom and an organic acid [a], more preferably a metal compound constituted by a metal atom of Groups 4, 5, and 14 and a carboxylic acid, and even more preferably a metal compound constituted by titanium, zirconium, hafnium, tantalum, tungsten, or tin and methacrylic acid or benzoic acid. The form in which the organic acid [a] is contained in the compound [A] also includes an organic acid anion formed by removing a hydrogen ion from the organic acid [a].

[0040] The compound (A) may contain one or more of the above metal compounds.

[0041] The compound (A) may contain one or more organic acids (a).

[0042] The lower limit of the content of the compound [A] relative to all components contained in the composition is preferably 2% by mass, more preferably 4% by mass, and even more preferably 6% by mass, and the upper limit of the content is preferably 30% by mass, more preferably 20% by mass, and even more preferably 15% by mass.

[0043] [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 metal-containing compound [b], etc. Here, the "hydrolysis condensation reaction" refers to a reaction in which a hydrolyzable group in metal-containing compound [b] is hydrolyzed to convert it to -OH, and the two resulting -OH groups undergo dehydration condensation to form -O-.

[0044] (Metal-Containing Compound [b]) The metal-containing compound [b] is a metal compound (b1) having a hydrolyzable group, a hydrolyzate of the metal compound (b1) having a hydrolyzable group, a hydrolysis condensate of the metal compound (b1) having a hydrolyzable group, or a combination thereof. The metal compound (b1) can be used alone or in combination of two or more.

[0045] Examples of the hydrolyzable group include a halogen atom, an alkoxy group, and an acyloxy group.

[0046] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0047] Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, and an n-butoxy group.

[0048] Examples of the acyloxy group include an acetoxy group, an ethyryloxy group, a propionyloxy group, a butyryloxy group, a t-butyryloxy group, a t-amylyloxy group, an n-hexanecarbonyloxy group, and an n-octanecarbonyloxy group.

[0049] The hydrolyzable group is preferably an alkoxy group or an acyloxy group, more preferably an isopropoxy group or an acetoxy group.

[0050] [b] When the metal-containing compound is a hydrolysis condensate of a metal compound (b1), the hydrolysis condensate of the metal compound (b1) may be a hydrolysis condensate of a metal compound (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 (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 (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.

[0051] Examples of the metal compound (b1) include a compound represented by the following formula (α) (hereinafter also referred to as “compound (m)”).

[0052]

[0053] In the above formula (α), M is a metal atom. L is a ligand. a is an integer of 0 to 2. When a is 2, 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 2 to 6. Multiple Ys may be the same or different. Note that L is a ligand that does not correspond to Y.

[0054] Examples of the metal atom represented by M include the same metal atoms as those exemplified as the metal atoms constituting the metal compound contained in the compound (A).

[0055] The ligand represented by L may be a monodentate ligand or a polydentate ligand.

[0056] Examples of the monodentate ligand include a hydroxo ligand, a carboxy ligand, an amide ligand, and ammonia.

[0057] The amide ligand may be, for example, an unsubstituted amide ligand (NH２ ), methylamide ligand (NHMe), dimethylamide ligand (NMe ２ ), diethylamide ligand (NEt ２ ), dipropylamide ligand (NPr ２ ) etc.

[0058] Examples of the polydentate ligand include hydroxy acid esters, β-diketones, β-ketoesters, β-dicarboxylic acid esters, hydrocarbons having a π bond, and diphosphines.

[0059] 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.

[0060] Examples of the β-diketone include 2,4-pentanedione, 3-methyl-2,4-pentanedione, and 3-ethyl-2,4-pentanedione.

[0061] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] Examples of the halogen atom represented by Y include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0066] Examples of the alkoxy group represented by Y include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

[0067] Examples of the acyloxy group represented by Y include an acetoxy group, an ethyryloxy group, a butyryloxy group, a t-butyryloxy group, a t-amylyloxy group, an n-hexanecarbonyloxy group, and an n-octanecarbonyloxy group.

[0068] Y is preferably an alkoxy group or an acyloxy group, more preferably an isopropoxy group or an acetoxy group.

[0069] As b, 3 and 4 are preferred, and 4 is more preferred.

[0070] [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.

[0071] [b] Examples of metal-containing compounds include zirconium tetra-n-butoxide, zirconium tetra-n-propoxide, zirconium tetraisopropoxide, hafnium tetraethoxide, indium triisopropoxide, hafnium tetraisopropoxide, hafnium tetra-n-propoxide, hafnium tetra-n-butoxide, tantalum pentaethoxide, tantalum penta-n-butoxide, tungsten pentamethoxide, tungsten penta-n-butoxide, tungsten hexaethoxide, tungsten hexa-n-butoxide, iron chloride, zinc diisopropoxide, zinc acetate dihydrate, ortho Tetrabutyl titanate, titanium tetra-n-butoxide, titanium tetra-n-propoxide, zirconium di-n-butoxide bis(2,4-pentanedionate), titanium tri-n-butoxide stearate, bis(cyclopentadienyl)hafnium dichloride, bis(cyclopentadienyl)tungsten dichloride, diacetato[(S)-(-)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl]ruthenium, dichloro[ethylenebis(diphenylphosphine)]cobalt, titanium butoxide oligomer, aminopropyltrimethoxytitanium, aminopropyltriethoxyzirconium, 2-(3,4-epoxycyclohexyl)ethyltrimethoxyzirconium, γ-glycidoxypropyltrimethoxyzirconium, 3-isocyanopropyltrimethoxyzirconium, 3-isocyanopropyltriethoxyzirconium, triethoxymono(acetylacetonate)titanium, tri-n-propoxymono(acetylacetonate)titanium, tri-isopropoxymono(acetylacetonate)titanium, triethoxymono(acetylacetonate)zirconium, tri-n-propoxymono(acetylacetonate) Examples of suitable cations include tri(3-methacryloxypropyl)methoxyzirconium, tri-isopropoxymono(acetylacetonato)zirconium, diisopropoxybis(acetylacetonato)titanium, di-n-butoxybis(acetylacetonato)titanium, di-n-butoxybis(acetylacetonato)zirconium, tri(3-methacryloxypropyl)methoxyzirconium, tri(3-acryloxypropyl)methoxyzirconium, tin tetraisopropoxide, tin tetra-n-butoxide, lanthanum oxide, and yttrium oxide.

[0072] Of these, metal alkoxides and metal acyloxides are preferred, metal alkoxides are more preferred, and alkoxides of titanium, zirconium, hafnium, tantalum, tungsten and tin are even more preferred.

[0073] When an organic acid is used in the synthesis of the compound [A], the lower limit of the amount of the organic acid used is preferably 1 mol, more preferably 2 mols, per mol of the metal-containing compound [b], while the upper limit of the amount of the organic acid used is preferably 6 mols, more preferably 5 mols, per mol of the metal-containing compound [b].

[0074] During the synthesis reaction of the compound [A], in addition to the metal compound (b1) and the organic acid [a], 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.

[0075] 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.

[0076] Examples of methods for carrying out a ligand exchange reaction using the metal-containing compound [b] include a method of mixing the metal-containing compound [b] and the organic acid [a]. In this case, the mixing may be carried out in a solvent or without using a solvent. In addition, a base such as triethylamine may be added to the mixing as needed. 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 metal-containing compound [b] and the organic acid [a] used.

[0077] 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, ester-based solvents, and hydrocarbon-based solvents are preferred, alcohol-based solvents, ether-based solvents, and ester-based solvents are more preferred, monoalcohol-based solvents, polyhydric alcohol partial ether-based solvents, and polyhydric alcohol partial ether carboxylate-based solvents are even more preferred, and monoalcohol-based solvents having 1 to 4 carbon atoms, propylene glycol monoethyl ether, and propylene glycol monomethyl ether acetate are particularly preferred.

[0078] When the solvent (d) is used in the synthesis reaction of the compound (A), the used solvent may be removed after the reaction, but it may also be used as the solvent (B) for the resist underlayer film-forming composition without being removed after the reaction.

[0079] [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).

[0080] 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.

[0081] Examples of alcohol solvents include monoalcohol solvents such as methanol, ethanol, and n-propanol, and polyalcohol solvents such as ethylene glycol, 1,2-propylene glycol, triethylene glycol, and tripropylene glycol.

[0082] 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.

[0083] Examples of the ether solvent 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] Other examples include aromatic solvents such as toluene, xylene, and mesitylene.

[0088] The solvent (B) is preferably an ether solvent, an ester solvent, a ketone solvent, or a combination thereof; more preferably a polyhydric alcohol partial ether solvent, an acetate monoester solvent, a polyhydric alcohol partial ether carboxylate solvent, a chain ketone solvent, or a combination thereof; and even more preferably propylene glycol monoethyl ether, butyl acetate, propylene glycol monomethyl ether acetate, 2-heptanone, or a combination thereof.

[0089] 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% by mass, more preferably 95% by mass, and more preferably 90% 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.

[0090] [Other Optional Components] The composition may contain other components in addition to those described above, such as an acid generator, a polymer additive, a polymerization inhibitor, a surfactant, and the like.

[0091] 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.

[0092] 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.

[0093] Examples of the acid generator include onium salt compounds and N-sulfonyloxyimide compounds.

[0094] 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.

[0095] Examples of the polymer additive include (poly)oxyalkylene polymer compounds, fluorine-containing polymer compounds, and non-fluorine-containing polymer compounds.

[0096] 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.

[0097] Examples of fluorine-containing polymer compounds include compounds described in JP 2011-89090 A. Examples of fluorine-containing polymer compounds 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).

[0098] 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 Examples of the compound include compounds containing one or more repeating units derived from a (meth)acrylate monomer such as (meth)acrylate having a - structure (n=1 to 17).

[0099] The composition may contain one or more polymerization inhibitors, which may enhance the storage stability of the composition.

[0100] Examples of the polymerization inhibitor include hydroquinone compounds such as 4-methoxyphenol and 2,5-di-tert-butylhydroquinone, and nitroso compounds such as N-nitrosophenylhydroxylamine and its aluminum salt.

[0101] 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.

[0102] 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 suitable fluoride-resistant coatings include "Fluoride 44," "Fluoride R30," "Fluoride F437," "Fluoride F475," "Fluoride F479," "Fluoride F482," "Fluoride F562," "Fluoride F563," "Fluoride F780," "Fluoride R-40," "Fluoride DS-21," "Fluoride RS-56," "Fluoride RS-90," and "Fluoride RS-72-K" (all manufactured by DIC Corporation), "Fluorade FC430" and "Fluorade FC431" (all manufactured by Sumitomo 3M Limited), "Asahiguard AG710," "Surflon S-382," "Surflon SC-101," "Surflon SC-102," "Surflon SC-103," "Surflon SC-104," "Surflon SC-105," and "Surflon SC-106" (all manufactured by AGC Inc.), "FTX-218," and "NBX-15" (manufactured by Neos Corporation).

[0103] [Method for preparing composition for forming resist underlayer film] The composition for forming resist underlayer film 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.

[0104] <Cleaning Solution> The cleaning solution contains an organic acid (E). Preferably, the cleaning solution further contains an organic solvent (hereinafter also referred to as "organic solvent (G)"). The cleaning solution may contain water as a solvent other than the organic solvent. The cleaning solution may contain other optional components as long as the effects of the present invention are not impaired. Examples of optional components include the components exemplified as the ligand represented by L in formula (α) above.

[0105] [[E] Organic Acid] The [E] organic acid is a non-polymeric organic acid. Adding the [E] organic acid to the cleaning solution facilitates removal of a film formed on the periphery of the substrate. The lower limit of the molecular weight of the [E] organic acid is preferably 45, more preferably 55, even more preferably 65, and particularly preferably 70, from the viewpoint of drainage stability. The upper limit of the molecular weight of the [C] organic acid is preferably 500, more preferably 400, and even more preferably 300. The [E] organic acid may be used alone or in combination of two or more. The [a] organic acid used in the synthesis of the [A] compound can be suitably used as the [E] organic acid.

[0106] The organic acid [E] is preferably a carboxylic acid. More specifically, examples thereof include carboxylic acids comprising an aliphatic saturated hydrocarbon group and / or an aromatic hydrocarbon group and a carboxy group, such as formic acid, acetic acid, propionic acid, butanoic acid (butyric acid), isobutanoic acid (isobutyric acid), pentanoic acid, hexanoic acid, 2-ethylhexanoic acid, cyclohexanecarboxylic acid, cyclohexylacetic acid, 1-adamantanecarboxylic acid, benzoic acid, and phenylacetic acid; fluorine atom-containing monocarboxylic acids, such as difluoroacetic acid, trifluoroacetic acid, pentafluoropropanoic acid, heptafluorobutanoic acid, fluorophenylacetic acid, and difluorobenzoic acid; monocarboxylic acids containing a heteroatom-containing group other than a fluorine atom in a moiety other than the carboxy group, such as 10-hydroxydecanoic acid, 5-oxohexanoic acid, 3-methoxycyclohexanecarboxylic acid, camphorcarboxylic acid, dinitrobenzoic acid, nitrophenylacetic acid, lactic acid, glycolic acid, glyceric acid, salicylic acid, anisic acid, gallic acid, and furancarboxylic acid; unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, 3-butenoic acid, angelic acid, tiglic acid, 4-pentenoic acid, cinnamic acid, sorbic acid, propiolic acid, and 2-butynoic acid; polycarboxylic acids comprising a single bond, an aliphatic saturated hydrocarbon group, and / or an aromatic hydrocarbon group and a plurality of carboxy groups, such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, dodecanedicarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, cyclohexanehexacarboxylic acid, 1,4-naphthalenedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, and 1,2,3,4-cyclobutanetetracarboxylic acid; partial esterification products of the above polycarboxylic acids; fluorine atom-containing polycarboxylic acids such as difluoromalonic acid, tetrafluorophthalic acid, and hexafluoroglutaric acid; Examples include polycarboxylic acids containing heteroatoms other than fluorine atoms in a moiety other than the carboxy group, such as tartaric acid, citric acid, malic acid, tartronic acid, diglycolic acid, and iminodiacetic acid; and unsaturated polycarboxylic acids such as maleic acid, fumaric acid, and aconitic acid.

[0107] From the viewpoints of cleaning properties and wastewater stability, the organic acid (E) is preferably an unsaturated carboxylic acid, more preferably an unsaturated monocarboxylic acid, and even more preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, and 3-butenoic acid.

[0108] The lower limit of the content of the organic acid [E] relative to all components contained in the cleaning solution is preferably 0.5 mass%, more preferably 1 mass%, even more preferably 2 mass%, and particularly preferably 3 mass%. The upper limit of the content is preferably 80 mass%, more preferably 70 mass%, even more preferably 65 mass%, and particularly preferably 60 mass%. By setting the content of the organic acid [E] within the above range, it is possible to further improve the cleaning performance and drainage stability.

[0109] [Organic Solvent (G)] As the organic solvent (G) that is preferably contained in the cleaning liquid, the organic solvents exemplified above as the solvent (B) that is contained in the composition for forming a resist underlayer film can be used.

[0110] The organic solvent (G) is preferably at least one selected from the group consisting of the ketone solvents and the ester solvents, more preferably the chain ketone solvents, the acetate monoester solvents, the polyhydric alcohol partial ether carboxylate solvents, or a combination thereof, and even more preferably butyl acetate, propylene glycol monomethyl ether acetate, 2-heptanone, or a combination thereof.

[0111] The lower limit of the content of the organic solvent [G] relative to the total amount of the organic acid [E] and the organic solvent [G] is preferably 20% by mass, more preferably 30% by mass, and more preferably 35% by mass, and the upper limit of the content is preferably 99% by mass, more preferably 98% by mass, and more preferably 95% by mass.

[0112] [Method for Preparing Cleaning Solution] The cleaning solution can be prepared by mixing the organic acid (E) and, if necessary, the organic solvent (G) and any optional components in a predetermined ratio, and filtering the resulting mixture preferably through a membrane filter or the like having a pore size of 0.5 μm or less.

[0113] [Coating Step] In the coating step, the composition for forming a resist underlayer film is directly or indirectly coated onto a substrate. The method for coating the composition for forming a resist underlayer film 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 resist underlayer film is formed by volatilization of the solvent (B).

[0114] 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.

[0115] 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 60 nm. The average thickness is measured according to the method described in the Examples.

[0116] 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).

[0117] 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 150°C, more preferably 200°C. The upper limit of the heating temperature is preferably 600°C, 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, more preferably 600 seconds.

[0118] [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.

[0119] 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.

[0120] [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.

[0121] An example of a case where a silicon-containing film is indirectly formed on a substrate having a resist underlayer film is a case where a surface-modified film of the resist underlayer film is formed on the resist underlayer film.

[0122] 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).

[0123] [Cleaning Step] In this step, the peripheral edge of the substrate is cleaned with a cleaning liquid. As the cleaning liquid, the cleaning liquid can be suitably used.

[0124] 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.

[0125] After the composition for forming a resist underlayer film is applied to a substrate, the cleaning step can be carried out with or without the heating step. When the cleaning step is carried out after the application step without the heating step, it is preferable to carry out the heating step after the cleaning step.

[0126] [Resist Pattern Forming Step] In this step, after the cleaning 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.

[0127] 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 as necessary to volatilize the solvent in the applied film, thereby forming a resist film.

[0128] Examples of the resist composition include a positive or negative chemically amplified resist composition containing a radiation-sensitive acid generator, a positive resist composition containing an alkali-soluble resin and a quinone diazide photosensitizer, a negative resist composition containing an alkali-soluble resin and a crosslinking agent, etc. In this step, a commercially available resist composition can also be used as is.

[0129] 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), Kr ２ 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.

[0130] 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.

[0131] 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.

[0132] After development with the developer, the resist is washed and dried to form a desired resist pattern.

[0133] [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.

[0134] 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 , SF６ 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 , reducing gases such as HF, HI, HBr, HCl, and NO, 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.

[0135] <<Method for Forming a Resist Underlayer Film>> The method for forming a resist underlayer film includes a step of applying a composition for forming a resist underlayer film directly or indirectly to a substrate. As the composition for forming a resist underlayer film, the composition for forming a resist underlayer film used in the method for producing a semiconductor substrate can be suitably used. As the coating step, the coating step in the method for producing a semiconductor substrate can be suitably used.

[0136] <<Cleaning Solution>> The cleaning solution contains an organic acid (E). Furthermore, it is preferable that the cleaning solution contains an organic solvent. The cleaning solution may contain water as a solvent other than the organic solvent. The cleaning solution used in the semiconductor substrate manufacturing method can be suitably used as such a cleaning solution.

[0137] 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.

[0138] In the present examples, the concentrations of components other than the solvent in the mixture containing the compound [A], the weight-average molecular weight (Mw) of the hydrolysis condensate in the mixture containing the compound [A], and the average thickness of the film were measured by the following methods.

[0139] [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].

[0140] [Weight-average molecular weight (Mw)] Measurement was performed by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard, under the following analytical conditions: GPC columns (two "AWM-H," one "AW-H," and two "AW2500" columns, all manufactured by Tosoh Corporation), a flow rate of 0.3 mL / min, an elution solvent of N,N-dimethylacetamide supplemented with LiBr (30 mM) and citric acid (30 mM), and a column temperature of 40°C.

[0141] [Average Thickness of Resist Underlayer Film] The average thickness of the resist underlayer film was determined by measuring the film thickness at arbitrary nine positions at 5 cm intervals including the center of the resist underlayer film using a spectroscopic ellipsometer (J.A. WOOLLAM's "M2000D") and calculating the average value of the film thicknesses.

[0142] <Synthesis of Compound [A]> The [m] compound, [x] compound, [d] solvent, and [B] solvent used in the synthesis of Compound [A] are shown below. In the synthesis examples below, unless otherwise specified, "parts by mass" means a value when the mass of the [m] compound used is taken as 100 parts by mass. Furthermore, "molar ratio" means a value when the substance amount of the [m] compound used is taken as 1. The concentrations (% by mass) of components other than the solvent in mixtures containing Compound [A] are also shown in Table 1. In Table 1 below, "-" indicates that the corresponding component was not used.

[0143] The following compounds were used as the compound [m]: m-1: tetra-n-propoxyzirconium(IV) m-2: tetra-n-butoxyzirconium(IV) m-3: tetra-n-propoxyhafnium(IV) m-4: tetraisopropoxytitanium(IV) m-5: pentaethoxytantalum(V) m-6: tetraisopropoxytin(IV)

[0144] The following compounds were used as the [x] compounds: x-1: propionic acid x-2: butyric acid x-3: isobutyric acid x-4: methacrylic acid x-5: 2-ethylhexanoic acid x-6: acetylacetone x-7: diethanolamine

[0145] [d] The following compounds were used as solvents: d-1: n-propyl alcohol, d-2: ethanol, d-3: 1-butanol, and d-4: isopropanol.

[0146] [B] The following compounds were used as the solvent: B-1: Propylene glycol monomethyl ether acetate B-2: Propylene glycol monoethyl ether

[0147] [Synthesis Example 1-1] (Synthesis of [A] Compound (A-1)) Compound (m-1) and solvent (d-1) (40 parts by mass) were placed in a reaction vessel under a nitrogen atmosphere. Compound (x-1) (molar ratio 5) was added dropwise to the reaction vessel over 20 minutes while stirring at 50°C. Next, the reaction was carried out at 80°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 n-hexane (100 parts by mass), and then vacuum dried to obtain compound (A-1).

[0148] Synthesis Example 1-2 (Synthesis of [A] Compound (A-2)) Under a nitrogen atmosphere, compound (m-1) and solvent (d-1) (200 parts by mass) were placed in a reaction vessel. Compound (x-2) (molar ratio 5) was added dropwise to the reaction vessel over 20 minutes while stirring at 50°C. Next, the reaction was carried out at 80°C for 3 hours. After completion of the reaction, the reaction vessel was cooled to 30°C or below. To the cooled reaction solution, 900 parts by mass of solvent (B-1) was added, and then solvent (d-1), the alcohol produced by the reaction, and excess solvent (B-1) were removed using an evaporator to obtain a mixture containing compound (A-2). The concentration of components other than the solvent in the mixture containing compound (A-2) [A] was 14% by mass.

[0149] Synthesis Examples 1-10 and 1-14 (Synthesis of [A] Compounds (A-10) and (A-14)) [A] Compounds (A-10) and (A-14) were obtained in the same manner as in Synthesis Example 1-1, except that the types and amounts of [m] compound, [x] compound, and [d] solvent shown in Table 1 below were used.

[0150] Synthesis Examples 1-3 to 1-9, 1-11 to 1-13, and 1-17 (Synthesis of [A] Compounds (A-3) to (A-9), (A-11) to (A-13), and (A-17)) Mixtures containing [A] Compounds (A-3) to (A-9), (A-11) to (A-13), and (A-17) were obtained in the same manner as in Synthesis Example 1-2, except that the types and amounts of [m] compound, [x] compound, [d] solvent, and [B] solvent shown in Table 1 below were used.

[0151] Synthesis Example 1-15 (Synthesis of [A] Compound (A-15)) Compound (m-4) was placed in a reaction vessel under a nitrogen atmosphere. Compound (x-6) (molar ratio 2) was added dropwise to the reaction vessel over 30 minutes while stirring at room temperature (25°C to 30°C). Then, a reaction was carried out at 60°C for 2 hours. After completion of the reaction, the reaction vessel was cooled to 30°C or below. The cooled reaction solution was diluted with solvent (d-4) (900 parts by mass). Water (molar ratio 2) was added dropwise to the reaction vessel over 10 minutes while stirring at room temperature (25°C to 30°C). Then, a hydrolysis and condensation reaction was carried out at 60°C for 2 hours. After completion of the hydrolysis and condensation reaction, the reaction vessel was cooled to 30°C or below. To the cooled reaction solution, 1,000 parts by mass of solvent (B-2) was added, and then water, isopropanol, the alcohol produced by the reaction, water, and excess solvent (B-2) were removed using an evaporator to obtain a mixture containing compound (A-15). [A] The concentration of components other than the solvent in the mixture containing compound (A-15) was 13% by mass.

[0152] Synthesis Example 1-16 (Synthesis of [A] Compound (A-16)) A mixture containing [A] Compound (A-16) was obtained in the same manner as in Synthesis Example 1-15, except that the types and amounts of the [m] compound, [x] compound, [d] solvent, and [B] solvent shown in Table 1 below were used.

[0153]

[0154] <Preparation of Composition> The compounds [A], solvents [B], and other optional components [F] used in the preparation of the composition are shown below.

[0155] As the compound [A], the compounds (A-1) to (A-17) synthesized above were used.

[0156] As the solvent [B], in addition to (B-1) and (B-2) used in the synthesis of the compound [A], the following compounds were used: B-3: cyclohexanone B-4: mesitylene B-5: butyl acetate B-6: 2-heptanone

[0157] [F] As other optional components, the following compounds were used: F-1: 4-Methoxyphenol

[0158] [Example 1-1] Preparation of Composition (J-1) As shown in Table 2 below, 10 parts by mass of [A] Compound (A-1) and 90 parts by mass of [B] Solvent (B-3) 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, "-" next to [F] Other optional components indicates that [F] Other optional components were not used. The same applies hereinafter.

[0159] [Example 1-2] Preparation of Composition (J-2) As shown in Table 2 below, a mixture containing [A] compound (A-2) and (B-1) as a solvent [B] were mixed so that the amount of the solvent [B] was 90 parts by mass (including the solvent [B] contained in the mixture containing the compound [A]) per 10 parts by mass of the components other than the solvent in the compound [A-2]. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) filter with a pore size of 0.2 μm to prepare composition (J-2).

[0160] Examples 1-3 to 1-29: Preparation of Compositions (J-3) to (J-29) Compositions (J-3) to (J-29) were prepared in the same manner as in Example 1-1 or Example 1-2, except that the type and content of each component were as shown in Table 2. In Table 2, "-" indicates that the corresponding component was not used.

[0161]

[0162] <Preparation of Cleaning Solution> The organic acids (E), organic solvents (G), and solvents other than the organic solvents (G) used in preparing the cleaning solution are shown below.

[0163] [E] The following compounds (E-1) to (E-10) were used as organic acids: E-1: formic acid, E-2: acetic acid, E-3: propionic acid, E-4: acrylic acid, E-5: butyric acid, E-6: isobutyric acid, E-7: methacrylic acid, E-8: crotonic acid, E-9: 2-ethylhexanoic acid, and E-10: oxalic acid.

[0164] The following compounds (G-1) to (G-4) and (G-6) to (G-7) were used as the organic solvent [G], and (G-5) was used as a solvent other than the organic solvent [G]. G-1: Propylene glycol monomethyl ether acetate G-2: Butyl acetate G-3: 2-heptanone G-4: Propylene glycol monomethyl ether G-5: Water G-6: Dimethyl sulfoxide G-7: Sulfolane

[0165] [Example 2-1] Preparation of cleaning solution (K-1) As shown in Table 3 below, 80 parts by mass of [G] organic solvent (G-1) was mixed with 20 parts by mass of [E] organic acid (E-1). The resulting solution was filtered through a polytetrafluoroethylene (PTFE) filter with a pore size of 0.2 μm to prepare cleaning solution (K-1). In Table 3 below, "-" indicates that the corresponding component was not used.

[0166] Examples 2-2 to 2-29 and Comparative Example 1-1 Preparation of cleaning solutions (K-2) to (K-29) and (k-1) Cleaning solutions (K-2) to (K-29) and (k-1) were prepared in the same manner as in Example 2-1, except that the types and contents of each component were as shown in Table 3 below.

[0167]

[0168] <Evaluation> Each of the compositions prepared above was evaluated for metal cleaning ability and wastewater stability according to the following methods. The evaluation results are shown in Tables 4-1 and 4-2 below.

[0169] [Metal cleaning properties] 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, and then, while rotating at 1,500 rpm, a cleaning solution discharge 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 a cleaning solution (K) was discharged at a discharge rate of 2 ml per second. The cleaning solution was then discharged at a discharge rate of 2 ml per second at a position 2 mm from the outer edge of the substrate to the center of the substrate for 10 seconds, 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 surfaces of the peripheral portions (front and back surfaces 0.3 mm from the edge) of the obtained evaluation substrate A were brought into contact with acid, and the entire amount of the liquid obtained by the contact was recovered as a measurement sample liquid, and the metal content was measured by inductively coupled plasma mass spectrometry (ICP-MS).

[0170] Except for using cleaning solution (k-1) as the cleaning solution, evaluation substrate B with a resist underlayer film having an average thickness of 30 nm was obtained in the same manner as in obtaining evaluation substrate A. The outermost surface of the peripheral portion (front and back surface regions 0.3 mm from the edge) of the obtained evaluation substrate B was brought into contact with acid, and the entire amount of the liquid obtained by contact was recovered as a measurement sample liquid, and the metal content was measured by inductively coupled plasma mass spectrometry (ICP-MS).

[0171] The metal cleaning ability was evaluated as "A" when the amount of metal constituting the [A] compound detected on evaluation substrate A was less than 10% of that on evaluation substrate B, "B" when it was 10% or more but less than 50%, and "C" when it was 50% or more.

[0172] [Effluent stability] A mixed solution was prepared by mixing equal amounts of composition (J) and cleaning solution (K), and the presence or absence of precipitation and turbidity was visually confirmed after standing for one week at 23° C. and −15° C. The effluent stability was evaluated as “A” when no precipitation or turbidity occurred after standing for one week at −15° C., and as “B” when no precipitation or turbidity occurred after standing for one week at 23° C. but precipitation or turbidity occurred after standing for one week at −15° C.

[0173]

[0174]

[0175] As can be seen from the results in Tables 4-1 and 4-2, the Examples were superior to the Comparative Examples in both metal cleaning performance and drainage stability.

[0176] The method for producing a semiconductor substrate of the present invention uses a cleaning solution that has excellent cleaning properties and drainage stability to clean the peripheral portion of the substrate, thereby enabling efficient production of high-quality semiconductor substrates. The method for forming a resist underlayer film of the present invention uses a cleaning solution that has excellent cleaning properties and drainage stability, enabling efficient formation of a desired resist underlayer film. The cleaning solution of the present invention is excellent in both cleaning properties and drainage stability. Therefore, these solutions can be suitably used in the production of semiconductor devices, which are expected to become even more miniaturized in the future.

Claims

1. A process of directly or indirectly applying a composition for forming a resist underlayer film to a substrate; and a step of cleaning the peripheral portion of the substrate with a cleaning liquid, The composition for forming a resist underlayer film, A metal compound, Solvent and Contains The cleaning solution contains an organic acid.

2. The cleaning solution according to claim 1, wherein the metal atoms contained in the metal compound belong to groups 3 to 16 of the periodic table.

3. A cleaning solution as described in claim 1, wherein the metal atom contained in the metal compound belongs to Group 4 of the periodic table.

4. A cleaning solution as described in claim 1, wherein the metal compound contains an organic acid as a component other than metal atoms.

5. A cleaning solution as described in claim 1, wherein the cleaning solution contains an organic solvent.

6. The cleaning solution according to claim 5, wherein the organic solvent is at least one selected from the group consisting of ketone-based solvents and ester-based solvents.

7. A cleaning solution as described in claim 1, wherein the organic acid contained in the cleaning solution is a carboxylic acid.

8. A cleaning solution described in any one of claims 1 to 7, wherein the organic acid contained in the cleaning solution is an unsaturated carboxylic acid.

9. The cleaning solution according to claim 7, wherein the carboxylic acid is at least one selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, and 3-butenoic acid.

10. A cleaning solution described in any one of claims 1 to 7, wherein the content of organic acids in the total components contained in the cleaning solution is 3% by mass or more and 60% by mass or less.

11. a step of directly or indirectly applying a composition for forming a resist underlayer film to a substrate; cleaning the peripheral portion of the substrate with a cleaning solution; a step of forming a resist pattern directly or indirectly on the resist underlayer film formed in the coating step after the cleaning step; Including, The composition for forming a resist underlayer film, A metal compound, Solvent and Contains The method for producing a semiconductor substrate, wherein the cleaning liquid contains an organic acid.

12. Prior to the resist pattern forming step, A step of forming an organic underlayer film directly or indirectly on the resist underlayer film. The method for manufacturing a semiconductor substrate according to claim 11 , further comprising:

13. Prior to the resist pattern forming step, A step of forming a silicon-containing film directly or indirectly on the resist underlayer film. The method for manufacturing a semiconductor substrate according to claim 11 , further comprising:

14. 12. The method for producing a semiconductor substrate according to claim 11, wherein the metal atom contained in the metal compound belongs to Groups 3 to 16 of the periodic table.

15. The method for manufacturing a semiconductor substrate according to claim 11 , wherein the metal atom contained in the metal compound belongs to Group 4 of the periodic table.

16. The method for manufacturing a semiconductor substrate according to claim 11 , wherein the metal compound contains an organic acid as a component other than metal atoms.

17. The method for manufacturing a semiconductor substrate according to claim 11 , wherein the cleaning liquid contains an organic solvent.

18. 18. The method for producing a semiconductor substrate according to claim 17, wherein the organic solvent is at least one selected from the group consisting of ketone-based solvents and ester-based solvents.

19. The method for manufacturing a semiconductor substrate according to claim 11, wherein the organic acid contained in the cleaning solution is a carboxylic acid.

20. The method for manufacturing a semiconductor substrate according to any one of claims 11 to 19, wherein the organic acid contained in the cleaning solution is an unsaturated carboxylic acid.

21. 20. The method for producing a semiconductor substrate according to claim 19, wherein the carboxylic acid is at least one selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, and 3-butenoic acid.

22. The method for manufacturing a semiconductor substrate according to any one of claims 11 to 19, wherein the content of the organic acid in all components contained in the cleaning solution is 3% by mass or more and 60% by mass or less.

23. a step of directly or indirectly applying a composition for forming a resist underlayer film to a substrate; cleaning the peripheral portion of the substrate with a cleaning liquid; Including, The composition for forming a resist underlayer film, A metal compound, Solvent and Contains The method for forming a resist underlayer film, wherein the cleaning liquid contains an organic acid.