Cleaning liquid and method for cleaning substrate

Abstract

A cleaning solution for cleaning a substrate on which a metal is exposed, the cleaning solution containing a basic compound, an amino acid, and water, the isoelectric point (p I) of the amino acid and the pH of the cleaning solution at 23 DEG C satisfying the condition of formula (1). The cleaning solution does not contain a nitrogen heterocyclic compound, and the concentration of the basic compound is less than 12 mass% with respect to the total mass of the cleaning solution. P I-2lt; pH lt; p I + 2 (1).

Description

Technical Field

[0001] The invention relates to a cleaning liquid and a cleaning method for a substrate.

[0002] This application claims priority based on Japanese Patent Application No. 2022-174693 filed in Japan on October 31, 2022, and the contents are incorporated herein by reference. Background Art

[0003] In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, the miniaturization of wiring patterns has been rapidly developed due to the advancement of photolithography technology. In the next generation of semiconductors, ruthenium, tungsten, molybdenum, etc. are being studied as wiring materials for the purpose of reducing resistance.

[0004] The wiring process includes a process of dry etching the wiring layer using a silicon-based hard mask layer as a mask, for example, in order to pattern the wiring for semi-damascene. Silicon-containing residues from the hard mask are attached to the substrate after the dry etching of the wiring layer. These residues can be removed by cleaning.

[0005] As a cleaning liquid for removing residues after etching in a wiring process, for example, Patent Document 1 describes a cleaning liquid for copper wiring residues that has a chelation stability constant with copper of 15 or more and is composed only of an amino acid having no thiol group and water. The cleaning liquid for copper wiring residues in Patent Document 1 is proposed as a cleaning liquid that does not damage copper wiring.

[0006] Non-Patent Document 1 describes that hydrofluoric acid solution, semi-aqueous alkaline mixture, etc. were tested as cleaning liquids for removing etching residues of molybdenum, and describes that the semi-aqueous alkaline mixture showed excellent residue removal performance in the test.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent No. 4375722

[0010] Non-patent literature

[0011] Non-patent document 1: Quoc-Toan Le et al., "Wet Cleaning of Molybdenum for Nano Interconnects", ECS Journal, 108(4)39-44 (2022) Summary of the invention

[0012] Technical problem to be solved by the invention

[0013] With the need for wiring patterns using low-resistance metals such as ruthenium, tungsten, and molybdenum, it is sought to develop cleaning solutions that can be applied to these wiring processes. Such cleaning solutions are preferably excellent in removing etching residues and have little damage to metal wiring. However, conventional cleaning solutions have concerns about damaging metal wiring such as molybdenum wiring.

[0014] The present invention has been made in view of the above circumstances, and a technical object thereof is to provide a cleaning liquid that can reduce damage to metal wiring such as molybdenum and tungsten and has excellent cleaning properties, and a method for cleaning a substrate using the cleaning liquid.

[0015] Solutions for solving the above technical problems

[0016] In order to solve the above-mentioned technical problems, the present invention adopts the following structure.

[0017] The first embodiment of the present invention is a cleaning solution for cleaning a substrate with metal exposed on the surface, comprising an alkaline compound, an amino acid and water, wherein the isoelectric point (pI) of the amino acid and the pH of the cleaning solution at 23°C satisfy the following formula (1):

[0018] pI-2 <pH<pI+2(1)

[0019] The cleaning liquid does not contain a nitrogen heterocyclic compound, and the concentration of the basic compound is less than 12% by mass relative to the total mass of the cleaning liquid.

[0020] A second aspect of the present invention is a method for cleaning a substrate, comprising the step of cleaning a substrate having metal exposed on a surface thereof using the cleaning solution of the first aspect.

[0021] Effects of the Invention

[0022] According to the present invention, it is possible to provide a cleaning liquid that can reduce damage to metal wiring such as molybdenum and has excellent cleaning properties, and a method for cleaning a substrate using the cleaning liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 An example of a substrate to which the cleaning liquid according to one embodiment is applied is shown. DETAILED DESCRIPTION

[0024] (Cleaning fluid)

[0025] The cleaning solution of the first embodiment of the present invention is used to clean a substrate with metal exposed on the surface. The cleaning solution of this embodiment comprises an alkaline compound, an amino acid and water. The pH of the cleaning solution of this embodiment at 23°C and the isoelectric point (pI) of the amino acid at 23°C satisfy the condition of the following formula (1).

[0026] pI-2 <pH<pI+2(1)

[0027] The cleaning liquid of the present embodiment does not contain a nitrogen heterocyclic compound. In the cleaning liquid of the present embodiment, the concentration of the basic compound is less than 12% by mass relative to the total mass of the cleaning liquid.

[0028] <Basic compound: (B) component>

[0029] The cleaning solution of the present embodiment contains an alkaline compound (hereinafter also referred to as "component (B)"). Component (B) is not particularly limited as long as it is an alkaline compound, except for nitrogen heterocyclic compounds. Nitrogen heterocyclic compounds are compounds containing an aromatic heterocycle containing a nitrogen atom (nitrogen-containing aromatic heterocycle) and / or an aliphatic heterocycle containing a nitrogen atom (nitrogen-containing aliphatic heterocycle). The nitrogen-containing heterocycle contained in the nitrogen heterocyclic compound may be monocyclic or polycyclic. As a specific example of a nitrogen heterocyclic compound, diazabicycloundecene may be cited.

[0030] (B) component is preferably a water-soluble alkaline compound. As (B) component, a water-soluble alkaline compound having a pH of 7.5 or more in a 0.01M aqueous solution measured with a pH meter at 23°C is more preferably a pH of 8 or more, and particularly preferably a pH of 8.5 or more. The upper limit of pH is not particularly limited, but is preferably 13 or less, and more preferably 12.5 or less. The pH meter is not particularly limited, and a commercially available pH meter may be used. As an example of a pH meter, a portable pH meter (D-73S) manufactured by Horiba, Ltd., etc. may be cited.

[0031] The component (B) may, for example, be a quaternary hydroxide (hereinafter also referred to as “component (B1)”) or an amine other than the component (B1) (except for nitrogen-containing heterocyclic compounds) (hereinafter also referred to as “component (B2)”).

[0032] 《Quaternary Hydroxide: (B1) Ingredient》

[0033] As the component (B1), a compound represented by the following general formula (b1) may be mentioned.

[0034] [Chemistry 1]

[0035]

[0036] [Wherein, Rb 1 ~Rb 4 Each independently represents a hydrocarbon group which may have a substituent; and Z represents a nitrogen atom or a phosphorus atom.]

[0037] In the formula (b1), Rb 1 ~Rb 4 Each independently represents a hydrocarbon group which may have a substituent.

[0038] R 1 ~Rb 4The hydrocarbon group which may have a substituent may be an aliphatic hydrocarbon group which may have a substituent, or may be an aromatic hydrocarbon group which may have a substituent.

[0039] R 1 ~Rb 4 The aliphatic hydrocarbon group in the formula (a) may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear or branched, and may contain a ring structure.

[0040] As the straight-chain aliphatic hydrocarbon group, there may be mentioned a straight-chain alkyl group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, further preferably 1 to 4 carbon atoms or 1 to 3 carbon atoms, and particularly preferably 1 or 2 carbon atoms. Specific examples include methyl, ethyl, n-propyl, n-butyl, n-pentyl and the like.

[0041] The branched aliphatic hydrocarbon group may be a branched alkyl group having 3 to 10 carbon atoms, preferably 3 to 8 carbon atoms, more preferably 3 to 6 carbon atoms, and further preferably 3 or 4 carbon atoms. Specific examples include isopropyl, isobutyl, tert-butyl, isopentyl, neopentyl, 1,1-diethylpropyl, and 2,2-dimethylbutyl.

[0042] The aliphatic hydrocarbon group containing a ring structure is an aliphatic hydrocarbon group containing an alicyclic group. The alicyclic group may be a monocyclic group or a polycyclic group. In the alicyclic group, a part of the carbon atoms constituting the alicyclic ring may be substituted with heteroatoms, and examples of the heteroatoms include oxygen atoms and sulfur atoms. 1 ~Rb 4 The aliphatic hydrocarbon group does not contain a nitrogen-containing aliphatic heterocycle.

[0043] The aliphatic hydrocarbon group of the monocyclic group may be a group obtained by removing one hydrogen atom from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms. Specific examples of the monocycloalkane include cyclopropane, cyclopentane, cyclohexane and the like.

[0044] The aliphatic hydrocarbon group of the polycyclic group may be a group obtained by removing one hydrogen atom from a polycycloalkane. The polycycloalkane preferably has 7 to 12 carbon atoms.

[0045] Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane and tetracyclododecane.

[0046] R 1 ~Rb 4The aromatic hydrocarbon group in is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be a monocyclic or polycyclic ring. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, further preferably 6 to 15, and particularly preferably 6 to 12.

[0047] As the aromatic ring, specifically, there can be mentioned aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, phenanthrene, etc.; aromatic heterocyclic rings obtained by replacing some carbon atoms constituting the aromatic hydrocarbon rings with heteroatoms, etc. As heteroatoms in the aromatic heterocyclic ring, there can be mentioned oxygen atoms, sulfur atoms, etc. As the aromatic heterocyclic ring, specifically, there can be mentioned thiophene rings, etc. Among them, Rb 1 ~Rb 4 The aromatic hydrocarbon group in does not contain a nitrogen-containing aromatic heterocyclic ring.

[0048] Specific examples of aromatic hydrocarbon groups include: groups obtained by removing one hydrogen atom from the aromatic hydrocarbon ring or aromatic heterocyclic ring (aryl group or heteroaryl group); groups obtained by removing one hydrogen atom from an aromatic compound containing two or more aromatic rings (for example, biphenyl, fluorene, etc.); groups obtained by replacing one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocyclic ring with an alkylene group (for example, arylalkyl groups such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, 2-naphthylethyl, etc.); and the like.

[0049] The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocyclic ring preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, and particularly preferably 1 carbon atom.

[0050] R 1 ~Rb 4 The hydrocarbon group in may have a substituent. The substituent is not particularly limited, and an example thereof is a hydroxyl group.

[0051] R 1 ~Rb 4 Preferably, it is an aliphatic hydrocarbon group which may have a substituent, more preferably a linear or branched alkyl group which may have a substituent, and further preferably a linear or branched hydroxyalkyl group, a linear or branched hydroxyalkyl group, or a hydrogen atom. The linear hydroxyalkyl group or the linear alkyl group preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and further preferably 1 or 2 carbon atoms. The branched hydroxyalkyl group or the linear alkyl group preferably has 3 to 6 carbon atoms, more preferably 3 carbon atoms.

[0052] In the above formula (b1), Z represents a nitrogen atom or a phosphorus atom.

[0053] When the component (B1) is a hydroxide of a quaternary amine, specific examples include tetraethylammonium hydroxide (TEAH), tetramethylammonium hydroxide (TMAH), tetrapropylammonium hydroxide (TPAH), dimethylbis(2-hydroxyethyl)ammonium hydroxide (DMEMAH), tetrabutylammonium hydroxide (TBAH), tetrapropylammonium hydroxide (TPAH), tris(2-hydroxyethyl)methylammonium hydroxide (THEMAH), choline, dimethyldiethylammonium hydroxide, tetraethanolammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, benzyltributylammonium hydroxide, and the like.

[0054] When the component (B1) is a quaternary phosphonium hydroxide, specific examples include tetrabutylphosphonium hydroxide, tetrapropylphosphonium hydroxide, tetraethylphosphonium hydroxide, tetramethylphosphonium hydroxide, tetraphenylphosphonium hydroxide, methyltriphenylphosphonium hydroxide, ethyltriphenylphosphonium hydroxide, propyltriphenylphosphonium hydroxide, butyltriphenylphosphonium hydroxide, benzyltriphenylphosphonium hydroxide, allyltriphenylphosphonium hydroxide, dodecyltriphenylphosphonium hydroxide, tetradecyltriphenylphosphonium hydroxide, hexadecyltriphenylphosphonium hydroxide, and hexadecyltributylphosphonium hydroxide.

[0055] As the component (B1), TEAH, TMAH, THEMAH, choline and tetrabutylphosphonium hydroxide are preferred, TEAH, TMAH, DMEMAH, THEMAH and choline are more preferred, and TEAH, TMAH and THEMAH are further preferred.

[0056] 《Amines other than component (B1): component (B2)》

[0057] The component (B2) is an amine that does not contain a nitrogen-containing heterocyclic ring and does not belong to the component (B1).

[0058] (B2) Components may, for example, be ammonia, hydroxylamine, a primary monoamine, a secondary monoamine, a tertiary monoamine, a quaternary ammonium salt other than hydroxides, a diamine or a polyamine.

[0059] Examples of the primary monoamine include alkylamines such as methylamine, ethylamine, propylamine, n-butylamine, isopropylamine, and tert-butylamine; cycloalkylamines such as cyclopentylamine, cyclohexylamine, and cyclohexanemethylamine; alkoxyamines such as methoxyethylamine, methoxypropylamine, methoxybutylamine, ethoxypropylamine, and propoxypropylamine; and alkanolmonoamines such as monoethanolamine and monopropanolamine (1-amino-2-propanol, 3-amino-1-propanol), but are not limited to these.

[0060] Examples of the secondary monoamine include alkylamines such as dimethylamine, diethylamine, methylethylamine, dipropylamine, diisopropylamine, dibutylamine, diisobutylamine, and butylmethylamine; cycloalkylamines such as N,N-dicyclohexylamine and N-cyclopentylcyclohexylamine; alkoxyamines such as methoxy(methylamine) and N-(2-methoxyethyl)ethylamine; monoalkanolmonoamines such as N-methylethanolamine, N-ethylethanolamine, N-propylethanolamine, N-isopropylethanolamine, N-butylethanolamine, N-isobutylethanolamine, N-methylpropanolamine, N-ethylpropanolamine, N-propylpropanolamine, N-isopropylpropanolamine, N-butylpropanolamine, and N-isobutylpropanolamine; and dialkanolmonoamines such as dimethanolamine, diethanolamine, 2-((hydroxymethyl)amino)ethanol, dipropanolamine, diisopropanolamine, and dibutanolamine, but the present invention is not limited thereto.

[0061] Examples of the tertiary monoamine include trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, dimethylethylamine, dimethylpropylamine, allyldiethylamine, dimethyl-n-butylamine, diethylisopropylamine and the like alkylamines; tricyclopentylamine, tricyclohexylamine and the like cycloalkylamines; N,N-dimethylethanolamine, N,N-diethylethanolamine, N,N-dipropylethanolamine, N,N-ethylmethylethanolamine, N,N-dimethylpropanolamine, N,N-diethylpropanolamine, N,N-dipropylpropanolamine, N,N-ethylmethyl The present invention also includes monoalkanol monoamines such as N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, N-isopropyldiethanolamine, N-butyldiethanolamine, N-isobutyldiethanolamine, N-methyldipropanolamine, N-ethyldipropanolamine, N-propyldipropanolamine, N-isopropyldipropanolamine, N-butyldipropanolamine, and N-isobutyldipropanolamine; and trialkanol monoamines such as triethanolamine, tripropanolamine, triisopropanolamine, and tributanolamine, but are not limited to these.

[0062] As quaternary ammonium salt, fluoride, chloride, bromide, iodide, sulfate, bisulfate, acetate etc. of quaternary ammonium can be cited.As quaternary ammonium cation, the cation identical with the cationic part of the formula (b1) can be cited.As the specific example of quaternary ammonium salt, tetraethylammonium chloride, tetramethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetrapropylammonium chloride, tetraethylammonium bromide, tetramethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetrapropylammonium bromide, tetraethylammonium fluoride, tetramethylammonium fluoride, tetrapropylammonium fluoride, tetrabutylammonium fluoride, tetrapropylammonium fluoride, tetraethylammonium iodide, tetramethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetrapropylammonium iodide, tetraethylammonium hydrogen sulfate, tetramethylammonium hydrogen sulfate, tetrapropylammonium hydrogen sulfate, tetrabutylammonium hydrogen sulfate, tetrapropylammonium hydrogen sulfate etc. can be cited, but are not limited to these.

[0063] The diamine may be any of a primary diamine, a secondary diamine, and a tertiary diamine. Examples of the primary diamine include, but are not limited to, 2-(2-aminoethylamino)ethanol (AEEA), ethylenediamine, butane-1,4-diamine, 1,3-propylenediamine, 1,6-hexanediamine, and pentane-1,5-diamine. Examples of the secondary diamine include, but are not limited to, N,N'-dimethylethylenediamine, N,N'-dimethylpropylenediamine, N,N'-diethylethylenediamine, N,N'-diethylpropylenediamine, and N,N'-diisopropylethylenediamine. Examples of the tertiary diamine include, but are not limited to, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, N,N,N',N'-tetramethyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,3-diaminobutane, N',N'-tetramethyl-1,4-diaminobutane and N,N,N',N'-tetramethylphenylenediamine.

[0064] Polyamines are compounds containing three or more amino groups. Polyamines may contain any of primary, secondary and tertiary amino groups. Examples of polyamines include spermine, spermidine, 3,3'-iminobis(propylamine), N,N-bis(3-aminopropyl)methylamine, N,N-bis(3-aminopropyl)butylamine, N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine, diethylenetriamine, N,N,N'-,N",N"-pentamethyldiethylenetriamine, N,N,N',N",N"-pentamethyldipropylenetriamine, etc.

[0065] The component (B2) may be any of the above-mentioned amines, preferably ammonia, hydroxylamine, a primary monoamine, a secondary monoamine, a tertiary monoamine, a quaternary ammonium salt, a diamine or a polyamine, more preferably ammonia, hydroxylamine, a primary monoamine or a diamine.

[0066] The component (B) is preferably the component (B1), a primary monoamine, a secondary monoamine, a tertiary monoamine, a quaternary ammonium salt, a diamine or a polyamine, more preferably the component (B1), a quaternary ammonium salt, a diamine or a polyamine, and particularly preferably the component (B1).

[0067] The component (B) is preferably the component (B2), more preferably a primary monoamine, ammonia, hydroxylamine or diamine, further preferably a primary monoamine, ammonia, hydroxylamine or primary diamine, and particularly preferably a primary monoamine or hydroxylamine. The primary monoamine is preferably a monoalkanol monoamine, and more preferably monoethanolamine.

[0068] (B) The component may be used alone or in combination of two or more.

[0069] The content of component (B) in the cleaning liquid of the present embodiment is less than 12% by mass relative to the total mass of the cleaning liquid. The content of component (B) is preferably less than 10% by mass, more preferably less than 8% by mass, further preferably less than 5% by mass, and particularly preferably less than 3% by mass relative to the total mass of the cleaning liquid. The lower limit of the content of component (B) is not particularly limited, and it can be exemplified by being more than 0.0001% by mass, preferably more than 0.001% by mass, more preferably more than 0.01% by mass, further preferably more than 0.05% by mass, particularly preferably more than 0.1% by mass or more than 0.5% by mass. If the content of component (B) is above the above preferred lower limit, it is easy to maintain the pH of the cleaning liquid at a higher pH. If the content of component (B) is below the above preferred upper limit, the corrosion resistance tends to become good.

[0070] The content of the component (B) in the cleaning liquid of the present embodiment may be in the range of 0.0001% by mass or more and less than 12% by mass, preferably 0.001% by mass to 10% by mass, more preferably 0.01% by mass to 8% by mass, and particularly preferably 0.05% by mass to 5% by mass, relative to the total mass of the cleaning liquid.

[0071] The molar concentration of the component (B) in the cleaning solution of the present embodiment is preferably 1.5 mol / L or less, more preferably 1.0 mol / L or less, further preferably 0.5 mol / L or less, and particularly preferably 0.1 mol / L or less, relative to the total volume of the cleaning solution. The lower limit of the molar concentration of the component (B) is not particularly limited, and may be 0.0001 mol / L or more, preferably 0.001 mol / L or more, and more preferably 0.01 mol / L or more, relative to the total volume of the cleaning solution.

[0072] The molar concentration range of the component (B) in the cleaning solution of the present embodiment is 0.0001 to 1.5 mol / L, preferably 0.001 to 1.0 mol / L, and more preferably 0.01 to 0.5 mol / L, relative to the total volume of the cleaning solution.

[0073] The cleaning liquid of the present embodiment may contain only one of the components (B1) and (B2), or may contain both the components (B1) and (B2). The cleaning liquid of the present embodiment may contain the component (B1) but not the component (B2); or may contain the component (B2) but not the component (B1). The cleaning liquid of the present embodiment may contain only one component (B1) but not other components (B1); or may contain more than two components (B1). The cleaning liquid of the embodiment may contain only one component (B2) but not other components (B2); or may contain more than two components (B2).

[0074] The cleaning solution of the present embodiment may not contain, for example, one or more selected from the group consisting of primary monoamines, secondary monoamines, tertiary monoamines, quaternary ammonium salts, diamines and polyamines. The cleaning solution of the present embodiment may not contain, for example, one or more of the alkaline compounds exemplified as the above specific examples. The cleaning solution of the present embodiment may not contain, for example, one or more selected from the group consisting of primary alkanol monoamines, secondary alkanol monoamines, tertiary alkanol monoamines, primary aromatic monoamines, secondary aromatic monoamines, tertiary aromatic monoamines, quaternary aromatic ammonium salts, primary aminophenols, secondary aminophenols, tertiary aminophenols, aromatic diamines and aromatic polyamines. The cleaning solution of the present embodiment may contain one (B) component selected from the group consisting of monoethanolamine, ammonia, hydroxylamine and 2-(2-aminoethylamino)ethanol without containing alkaline compounds other than these. For example, the cleaning liquid of this embodiment may not contain one or more selected from the group consisting of ammonia, 2-hydroxyethyltrimethylammonium hydroxide, tetrabutylammonium hydroxide, 2-amino-2-methyl-1-propanol, diethanolamine, trishydroxymethylaminomethane, dimethylbis(2-hydroxyethyl)ammonium hydroxide and 2-(2-aminoethoxy)ethanol.

[0075] <Chelating Agent: Component (A)>

[0076] The cleaning solution of the present embodiment contains an amino acid as a chelating agent (hereinafter also referred to as "component (A1)").

[0077] 《Amino Acids: (A1) Ingredients》

[0078] Examples of the component (A1) include alanine (isoelectric point: 6.00), arginine (isoelectric point: 10.76), asparagine (isoelectric point: 5.41), cysteine ​​(isoelectric point: 5.07), glutamine (isoelectric point: 5.65), glycine (isoelectric point: 5.97), histidine (isoelectric point: 7.59), isoleucine (isoelectric point: 5.97), leucine (isoelectric point: 5.98), lysine (isoelectric point: 9.74), ornithine (isoelectric point: 9.70), methionine (isoelectric point: 5.74), phenylalanine (isoelectric point: 5.48), (isoelectric point: 5.97), serine (isoelectric point: 5.68), threonine (isoelectric point: 5.60), tryptophan (isoelectric point: 5.89), tyrosine (isoelectric point: 5.66), and valine (isoelectric point: 5.96).

[0079] As component (A1), neutral amino acids or basic amino acids are preferred, and basic amino acids are more preferred. As neutral amino acids, alanine, asparagine, cysteine, glutamine, glycine, isoleucine, leucine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine and valine can be mentioned. As basic amino acids, arginine, histidine, lysine, ornithine can be mentioned, and arginine or lysine is preferred, and arginine is more preferred.

[0080] Based on the relationship with the pH of the washing solution described below, the amino acid preferably has an isoelectric point of 5 or more, more preferably 7 or more, further preferably 8 or more, and particularly preferably 9 or more. The range of the isoelectric point of the amino acid is preferably 5 to 13, more preferably 8.5 to 13, further preferably 9 to 11, and particularly preferably 10 to 11.

[0081] The component (A1) may be used alone or in combination of two or more.

[0082] The content of component (A1) may be 0.0001% by mass or more, preferably 0.001% by mass or more, more preferably 0.005% by mass or more, further preferably 0.01% by mass or more, and particularly preferably 0.02% by mass or more, relative to the total mass of the cleaning liquid. When the content of component (A1) is at least the above preferred lower limit, the corrosion resistance of the cleaning liquid is easily improved.

[0083] The content of component (A1) is preferably 5% by mass or less, more preferably 4% by mass or less, more preferably 3% by mass or less, further preferably 1% by mass or less, and particularly preferably 0.5% by mass or less, relative to the total mass of the cleaning liquid. If the content of component (A1) is below the above preferred upper limit, it is easy to achieve a balance with other components.

[0084] The content of the component (A1) in the cleaning liquid of the present embodiment may be in the range of 0.0001% to 5% by mass, preferably 0.001% to 3% by mass, more preferably 0.005% to 1% by mass, and particularly preferably 0.01% to 0.5% by mass, relative to the total mass of the cleaning liquid.

[0085] The cleaning agent of this embodiment may not contain amino acids other than basic amino acids, and may not contain acidic amino acids and / or neutral amino acids. The cleaning solution of this embodiment may also contain one amino acid selected from the group consisting of arginine, lysine, and histidine, and may not contain amino acids other than these.

[0086] <<Chelating agent other than component (A1): component (A2)>>

[0087] The cleaning liquid of the present embodiment may contain a chelating agent other than the component (A1) (hereinafter also referred to as "component (A2)").

[0088] The component (A2) is not particularly limited as long as it is a compound having a function of chelating with a metal. As the component (A2), a compound having a ligand coordinated to a metal can be cited. As the ligand, for example, an acidic group can be cited. As the acidic group, for example, a carboxyl group, a phosphonic acid group, a sulfonic group, and a phenolic hydroxyl group can be cited.

[0089] As (A2) component, a carboxylic acid type chelating agent, a phosphonic acid type chelating agent, and an inorganic type chelating agent are mentioned, for example.

[0090] Carboxylic acid chelating agents:

[0091] The carboxylic acid chelating agent is a chelating agent having a carboxyl group as a ligand in the molecule. Examples of the carboxylic acid chelating agent include aminopolycarboxylic acid chelating agents, hydroxycarboxylic acid chelating agents, and aliphatic carboxylic acid chelating agents.

[0092] Examples of the aminopolycarboxylic acid chelating agent include butanediaminetetraacetic acid, diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetrapropionic acid, triethylenetetraaminehexaacetic acid, 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid, propylenediaminetetraacetic acid, ethylenediaminetetraacetic acid (EDTA), trans-1,2-diaminocyclohexanetetraacetic acid, ethylenediaminediacetic acid, ethylenediaminedipropionic acid, 1,6-hexamethylenediamine-N,N,N',N'-tetraacetic acid, N,N-bis(2-hydroxybenzyl)ethylenediamine-N,N-diacetic acid, diaminopropanetetraacetic acid, 1,4,7,10-tetraazacyclododecane-tetraacetic acid, diaminopropanoltetraacetic acid, (hydroxyethyl)ethylenediaminetriacetic acid, and iminodiacetic acid (IDA).

[0093] Examples of the hydroxycarboxylic acid chelating agent include malic acid, citric acid, glycolic acid, gluconic acid, heptonic acid, tartaric acid and lactic acid.

[0094] Examples of the aliphatic carboxylic acid chelating agent include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, sebacic acid and maleic acid.

[0095] Phosphonic acid chelating agents:

[0096] Phosphonic acid chelating agents are chelating agents having at least one phosphonic acid group in the molecule. Examples of phosphonic acid chelating agents include ethylaminobis(methylenephosphonic acid), dodecylaminobis(methylenephosphonic acid), nitrilotri(methylenephosphonic acid) (NTPO), ethylenediaminebis(methylenephosphonic acid) (EDDPO), 1,3-propylenediaminebis(methylenephosphonic acid), ethylenediaminetetra(methylenephosphonic acid) (EDTPO), ethylenediaminetetra(ethylenephosphonic acid), 1,3-propylenediaminetetra(methylenephosphonic acid) (PDTMP), 1,2-diaminopropanetetra(methylenephosphonic acid), 1,6-hexamethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid) (DEPPO), diethylenetriaminepenta(ethylenephosphonic acid), triethylenetetraaminehexa(methylenephosphonic acid) or triethylenetetraaminehexa(ethylenephosphonic acid).

[0097] Inorganic chelating agents:

[0098] Examples of the inorganic chelating agent include condensed phosphoric acid and salts thereof, and examples of the inorganic chelating agent include pyrophosphoric acid and salts thereof, metaphosphoric acid and salts thereof, tripolyphosphoric acid and salts thereof, and hexametaphosphoric acid and salts thereof.

[0099] The cleaning agent of this embodiment may or may not contain the component (A2). The cleaning agent of this embodiment may or may not contain one or more selected from the group consisting of aminopolycarboxylic acid chelating agents, hydroxycarboxylic acid chelating agents, aliphatic carboxylic acid chelating agents, phosphonic acid chelating agents and inorganic chelating agents. The cleaning agent of this embodiment may or may not contain one or more of the compounds listed above as specific examples of the component (A2). The cleaning agent of this embodiment may not contain tartaric acid and iminodiacetic acid.

[0100] <Water: (D) ingredient>

[0101] The cleaning solution of the present embodiment contains water as a solvent. Water may also contain trace components that are inevitably mixed in. The water used in the cleaning solution of the present embodiment is preferably water that has been purified, such as distilled water, ion exchange water, and ultrapure water, and ultrapure water commonly used in semiconductor manufacturing is more preferably used.

[0102] The content of water in the cleaning liquid of the present embodiment is not particularly limited, and a necessary amount for adjusting each component to a desired concentration can be used.

[0103] <Optional Ingredients>

[0104] The cleaning liquid of the present embodiment may contain an optional component in addition to the above-mentioned component (B), component (A), and component (D). Examples of the optional component include an organic solvent, a surfactant, a pH adjuster, and an anticorrosive agent.

[0105] 《Organic solvents: (S)》

[0106] In the range that does not impair the effect of the present invention, the cleaning solution of this embodiment may contain an organic solvent. The organic solvent is preferably a water-soluble organic solvent. As the water-soluble organic solvent, alcohols (such as isopropanol, ethanol, ethylene glycol, propylene glycol, glycerol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, diethylene glycol, dipropylene glycol, furfuryl alcohol and 2-methyl-2,4-pentanediol, 3-methoxy-3-methyl-1-butanol, etc.) can be cited; dimethyl sulfoxide; ethers (such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, propylene glycol dimethyl ether); and morpholines (such as N-methylmorpholine N-oxide) and the like.

[0107] The organic solvent is preferably an alcohol, more preferably a polyol, further preferably a diol, and particularly preferably ethylene glycol.

[0108] The organic solvent may be used alone or in combination of two or more.

[0109] When the cleaning liquid of the present embodiment contains an organic solvent, the content of the organic solvent is preferably 90% by mass or less, more preferably 80% by mass or less relative to the total amount of the amount of water and the amount of the organic solvent. When the cleaning liquid of the present embodiment contains an organic solvent, the range of the content of the organic solvent is preferably 1 to 90% by mass, more preferably 10 to 90% by mass, further preferably 50 to 90% by mass, and particularly preferably 70 to 80% by mass relative to the total mass of the cleaning liquid.

[0110] The cleaning solution of the present embodiment may or may not contain an organic solvent. The cleaning solution of the present embodiment may or may not contain one or more of the compounds listed above as specific examples of the organic solvent.

[0111] 《pH adjuster: (C)》

[0112] The cleaning solution of the present embodiment may contain a pH adjuster in order to adjust the pH of the cleaning solution. Examples of the pH adjuster include acidic compounds.

[0113] The acidic compound may be an inorganic acid or an organic acid.

[0114] Examples of the inorganic acid include hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, boric acid, and hexafluorophosphoric acid. The acidic compound may be a salt of an inorganic acid. Examples of the salt of an inorganic acid include ammonium salts of an inorganic acid. Examples of the ammonium salt of an inorganic acid include ammonium chloride, ammonium sulfate, ammonium sulfite, ammonium nitrate, ammonium nitrite, ammonium phosphate, ammonium borate, and ammonium hexafluorophosphate.

[0115] Examples of the organic acid include aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, oxalic acid, tartaric acid and citric acid. Aliphatic carboxylic acids can also be used as the component (A2).

[0116] As the pH adjuster, one type may be used alone, or two or more types may be used in combination.

[0117] The pH adjuster can be used in an amount necessary to adjust the cleaning solution to a desired pH. When the cleaning solution of the present embodiment contains a pH adjuster, the content of the pH adjuster may be, for example, 0.03 to 10% by mass relative to the total mass of the cleaning solution.

[0118] The cleaning solution of the present embodiment may or may not contain a pH adjuster. The cleaning solution of the present embodiment may or may not contain one or more of the compounds listed above as specific examples of the pH adjuster.

[0119] Surfactants

[0120] The cleaning liquid of this embodiment may contain a surfactant for the purpose of adjusting the wettability of the cleaning liquid to the substrate, etc. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.

[0121] Examples of the nonionic surfactant include polyoxyalkylene alkylphenyl ether surfactants, polyoxyalkylene alkyl ether surfactants, block polymer surfactants composed of polyethylene oxide and polypropylene oxide, polyoxyalkylene distyrenated phenyl ether surfactants, polyalkylene tribenzyl phenyl ether surfactants, and acetylene polyalkylene oxide surfactants.

[0122] Examples of the anionic surfactant include salts of alkylsulfonic acid, alkylbenzenesulfonic acid, alkylnaphthalenesulfonic acid, alkyldiphenylethersulfonic acid, fatty acid amidesulfonic acid, polyoxyethylene alkylethercarboxylic acid, polyoxyethylene alkyletheracetic acid, polyoxyethylene alkyletherpropionic acid, alkylphosphonic acid, and fatty acids. Examples of the "salt" include ammonium salts, sodium salts, potassium salts, and tetramethylammonium salts.

[0123] Examples of the cationic surfactant include alkylpyridinium surfactants, etc. A quaternary ammonium salt surfactant can be used as the component (B2).

[0124] Examples of the amphoteric surfactant include betaine-based surfactants, amino acid-based surfactants, imidazoline-based surfactants and amine oxide-based surfactants.

[0125] These surfactants are generally commercially available. The surfactant may be used alone or in combination of two or more.

[0126] When the cleaning liquid of the present embodiment contains a surfactant, the content of the surfactant is not particularly limited, and is preferably 0.0001% to 5% by mass, more preferably 0.0002% to 3% by mass, further preferably 0.002% to 1% by mass, and particularly preferably 0.002% to 0.2% by mass, relative to the total mass of the cleaning liquid. When the content of the surfactant is within the above preferred range, the bubbles generated by the foaming agent tend to become dense.

[0127] The cleaning solution of this embodiment may or may not contain a surfactant. The cleaning solution of this embodiment may or may not contain one or more selected from the group consisting of a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant. The cleaning solution of this embodiment may or may not contain one or more of the compounds listed above as specific examples of the surfactant.

[0128] 《Corrosion inhibitor》

[0129] The cleaning liquid of this embodiment may contain an anticorrosive agent.

[0130] Examples of the anticorrosive agent include ascorbic acids such as ascorbic acid, ascorbic acid phosphate and ascorbic acid sulfate; catechols such as pyrocatechol, 4-tert-butylcatechol, pyrogallol, gallic acid, methyl gallate, 1,2,4-benzenetriol and sodium catechol-3,5-disulfonate; sugars such as fructose, glucose and ribose; polycarboxylic acids such as polyacrylic acid, polymaleic acid and copolymers thereof, and the like.

[0131] The anticorrosive agent may be used alone or in combination of two or more.

[0132] When the cleaning liquid of the present embodiment contains an anticorrosive agent, the content of the anticorrosive agent is not particularly limited, but is preferably 0.0001% to 0.2% by mass, more preferably 0.0003% to 0.1% by mass, further preferably 0.0005% to 0.05% by mass, and particularly preferably 0.01% to 0.03% by mass, relative to the total mass of the cleaning liquid.

[0133] The cleaning solution of this embodiment may not contain one or more selected from the group consisting of ascorbic acid, catechols, sugars, and polycarboxylic acids, and may not contain one or more of the compounds listed above as specific examples of anticorrosives. The cleaning solution of this embodiment may not contain an anticorrosive.

[0134] Buffer

[0135] The cleaning solution of this embodiment may contain a buffer. A buffer is a compound that has the function of suppressing pH changes in a solution.

[0136] The buffer is not particularly limited as long as it is a compound having pH buffering ability. For example, a compound having a pKa of 6 to 11 can be used as the buffer.

[0137] Examples of the buffer include Good's buffer. Examples of Good's buffer include 2-cyclohexylaminoethanesulfonic acid (CHES), 3-cyclohexylaminopropanesulfonic acid (CAPS), N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid (TAPS), 4-(cyclohexylamino)-1-butanesulfonic acid (CABS), tris(hydroxymethyl)methylglycine (tricine), N,N-bis(2-hydroxyethyl)glycine (bicine), 2-morpholinoethanesulfonic acid monohydrate (MES), bis(2-hydroxyethyl)aminotris(hydroxymethyl)methane (Bis-Tris), N-(2-acetamido)iminodiacetic acid (ADA), piperazine-1,4-bis(2-ethanesulfonic acid) (P IPES), N-(2-acetamido)-2-aminoethanesulfonic acid (ACES), 2-hydroxy-3-morpholinopropanesulfonic acid (MOPSO), N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES), 3-morpholinopropanesulfonic acid (MOPS), N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES), 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES), 3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic acid (TAPSO), piperazine-1,4-bis(2-hydroxypropanesulfonic acid) (POPSO), 4-(2-hydroxyethyl)piperazine-1-(2-hydroxypropane-3-sulfonic acid) (HEPSO), 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid (EPPS), etc.

[0138] The buffer may be used alone or in combination of two or more.

[0139] When the cleaning solution of the present embodiment contains a buffer, the content of the buffer is not particularly limited, and may be, for example, 0.001% to 10% by mass, preferably 0.005% to 5% by mass, further preferably 0.01% to 1% by mass, particularly preferably 0.05% to 0.5% by mass or 0.05% to 0.3% by mass relative to the total mass of the cleaning solution.

[0140] The cleaning solution of the present embodiment may or may not contain a buffer. The cleaning solution of the present embodiment may or may not contain one or more of the compounds listed above as specific examples of the buffer.

[0141] Impurities, etc.

[0142] The cleaning liquid of the present embodiment may contain metal impurities containing metal atoms such as Fe atoms, Cr atoms, Ni atoms, Zn atoms, Ca atoms or Pb atoms. The total content of the above-mentioned metal atoms in the cleaning liquid of the present embodiment is preferably less than 100 mass ppt relative to the total mass of the cleaning liquid. The lower the lower limit of the total content of metal atoms, the more preferred it is, for example, 0.001 mass ppt or more can be cited. The total content of metal atoms can be, for example, 0.001 mass ppt to 100 mass ppt. By making the total content of metal atoms below the above-mentioned preferred upper limit, the defect suppression and residue suppression of the cleaning liquid are improved. It can be considered that by setting the total content of metal atoms to above the above-mentioned preferred lower limit, metal atoms are not likely to exist in the system in a free state, and are not likely to have an adverse effect on the overall manufacturing yield of the cleaning object.

[0143] The content of metal impurities can be adjusted, for example, by purification treatment such as filtration. Purification treatment such as filtration may be performed on a part or all of the raw materials before preparing the cleaning solution, or may be performed after preparing the cleaning solution.

[0144] The cleaning solution of the present embodiment may contain, for example, impurities derived from organic matter (organic impurities). The total content of the above-mentioned organic impurities in the cleaning solution of the present embodiment is preferably 5000 mass ppm or less. The lower limit of the content of organic impurities is more preferred as the lower limit is, for example, 0.1 mass ppm or more can be cited. As the total content of organic impurities, for example, 0.1 mass ppm to 5000 mass ppm can be cited.

[0145] The cleaning liquid of the present embodiment may also contain counted bodies of a size that can be counted by a light scattering liquid particle counter, for example. The size of the counted bodies is, for example, 0.04 μm or more. The number of counted bodies in the cleaning liquid of the present embodiment is, for example, less than 1,000 per 1 mL of cleaning liquid, and the lower limit is, for example, more than 1. It is believed that by making the number of counted bodies in the cleaning liquid within the above range, the metal corrosion inhibition effect brought by the cleaning liquid is improved.

[0146] The organic impurities and / or counted objects may be added to the cleaning solution or may be inevitably mixed into the cleaning solution during the manufacturing process of the cleaning solution. Examples of the cases where the organic impurities are inevitably mixed into the cleaning solution during the manufacturing process of the cleaning solution include, but are not limited to, the cases where the organic impurities are contained in the raw materials (e.g., organic solvents) used in the manufacturing of the cleaning solution and the cases where the organic impurities are mixed into the cleaning solution from the external environment (e.g., contamination) during the manufacturing process of the cleaning solution.

[0147] When the counted object is added to the cleaning liquid, the existence ratio may be adjusted for each specific size in consideration of the surface roughness of the cleaning object and the like.

[0148] <ph>

[0149] From the viewpoint of cleaning properties, the pH of the cleaning liquid of the present embodiment is preferably 8 or more. The pH of the cleaning liquid of the present embodiment is more preferably 9 or more, further preferably pH 9.5 or more, and particularly preferably pH 10 or more. From the viewpoint of corrosion resistance, the pH of the cleaning liquid of the present embodiment is preferably 13 or less, more preferably 12.5 or less, and further preferably 12 or less. The pH range of the cleaning liquid of the present embodiment may be pH 8 to pH 13, preferably pH 9 to 13, further preferably pH 9 to 12, and particularly preferably pH 10 to 12.

[0150] The pH value is a value measured by a pH meter under the conditions of normal temperature (23° C.) and normal pressure (1 atmosphere). Examples of the pH meter include a portable pH meter (D-73S) manufactured by Horiba, Ltd.

[0151] The isoelectric point (pI) of the amino acid as the component (A1) of the cleaning solution of the present embodiment and the pH of the cleaning solution at 23° C. satisfy the following formula (1).

[0152] pI-2 <pH<pI+2(1)

[0153] By making the pH of the cleaning liquid and the isoelectric point of the component (A1) satisfy the relationship of the above formula (1), it is possible to improve the corrosion resistance to metal wiring such as molybdenum while maintaining good cleaning performance.

[0154] <Storage Container>

[0155] The storage method of the cleaning liquid of this embodiment is not particularly limited, and the storage container can also use a conventionally known container. In order to ensure the stability of the cleaning liquid, the void ratio in the container when stored in the container and / or the type of gas filling the void portion can be appropriately set. For example, the void ratio in the storage container can be about 0.01 to 30 volume %.

[0156] The cleaning solution of the present embodiment may be diluted 2 to 2000 times before use to obtain a diluted solution, and the cleaning step may be carried out using the diluted solution.

[0157] In one embodiment, the cleaning solution of this embodiment does not contain one or more selected from the group consisting of inorganic alkaline compounds, hydroxycarboxylic acids, aminopolycarboxylic acids, polyphosphonic acids, acidic amino acids (glutamic acid, aspartic acid, etc.), alkanediols, fatty acids, phosphonic acids, sulfates, alkenylsuccinic acids, organic acids, water-soluble polymers, N,N,N',N",N"-pentamethyldiethylenetriamine, ethyleneamines, aliphatic polycarboxylic acids, oxalic acid, non-phenolic organic acids, and phenols.

[0158] <Substrate>

[0159] The substrate to which the cleaning liquid of this embodiment is applied is a substrate with a metal exposed on the surface. Examples of the above-mentioned metal include copper, cobalt, titanium, tantalum, ruthenium, molybdenum, tungsten, and aluminum, preferably copper, cobalt, molybdenum, or tungsten, and more preferably molybdenum and tungsten. The metal may be in the form of an oxide, carbide, or nitride, for example, aluminum oxide, tungsten carbide, titanium nitride, tantalum nitride, and aluminum nitride.

[0160] As a substrate, it is preferred to include a metal-containing layer containing a metal. The metal contained in the metal-containing layer may be a single substance, an alloy, or a compound. As a metal compound, for example, oxides, nitrides, nitrogen oxides, carbides, etc. may be mentioned. The content of the metal in the metal-containing layer is preferably 20% by mass or more, more preferably 50% by mass or more, further preferably 80% by mass or more, and may be 100% by mass, relative to the total mass of the composition forming the metal-containing layer. The metal-containing layer can be formed by a known method, for example, CVD, ALD, PVD, etc. can be used.

[0161] The metal-containing layer is preferably a wiring layer. The metal-containing layer may be, for example, a molybdenum wiring layer or a tungsten wiring layer. The cleaning solution of this embodiment may be used, for example, to clean a substrate after dry etching of the metal-containing layer. More specifically, the cleaning solution of this embodiment may be used to clean a substrate after dry etching of a metal wiring layer (molybdenum wiring layer, tungsten wiring layer, etc.).

[0162] Figure 1 An example of a substrate to which the cleaning liquid of the present embodiment is applied is shown. Figure 1 The substrate 1 shown is, for example, a substrate after dry etching of a wiring layer. In the substrate 1, a wiring layer 10 is formed on a dielectric layer 30, and a hard mask layer 20 is formed on the wiring layer 10. The substrate 1 is a substrate after dry etching of the wiring layer 10 using the hard mask layer 20 as a mask. Residue 40, which is a residue of dry etching, is attached to the substrate 1.

[0163] In the substrate 1, the wiring layer 10 is a metal wiring layer. The hard mask layer 20 is made of, for example, silicon dioxide (SiO 2 ) or silicon nitride (SiN). The residue 40 includes molybdenum oxide or tungsten oxide and silicon-containing residue.

[0164] When the substrate 1 is cleaned with a conventional cleaning liquid, the metal included in the wiring layer 10 corrodes due to contact with the cleaning liquid. Therefore, the metal wiring is damaged by the cleaning process.

[0165] On the other hand, in the cleaning liquid of this embodiment, the metal is protected by containing the component (A1). On the other hand, the silicon-containing residue 40 can be well cleaned by containing the component (B). Therefore, the residue 40 can be cleaned while protecting the wiring layer 10 containing the metal (molybdenum, tungsten, etc.).

[0166] According to the cleaning solution of this embodiment, since it contains a basic compound (B) and an amino acid (A1), and the isoelectric point of the component (A1) and the pH of the cleaning solution at 23° C. satisfy the condition of the above formula (1), in a substrate with a metal (molybdenum, tungsten, etc.) exposed on the surface, it is possible to well clean silicon-containing residues while protecting the metal. Therefore, it can be suitably used for cleaning a substrate after dry etching of a metal wiring layer (molybdenum wiring layer, tungsten wiring layer, etc.).

[0167] Furthermore, the cleaning liquid of the present embodiment does not contain a nitrogen heterocyclic compound, and the concentration of the component (B) is less than 12% by mass, whereby the anticorrosion effect of the component (A1) can be sufficiently obtained.

[0168] (Substrate cleaning method)

[0169] The cleaning method of the substrate of the second embodiment includes a step of cleaning the substrate using the cleaning solution of the first embodiment. The substrate is a substrate with a metal exposed on the surface. Examples of the metal include copper, cobalt, titanium, tantalum, ruthenium, molybdenum, and tungsten, preferably copper, cobalt, molybdenum, or tungsten, and more preferably molybdenum or tungsten. The metal may be in the form of an oxide, a carbide, or a nitride, for example, aluminum oxide, tungsten carbide, titanium nitride, tantalum nitride, and aluminum nitride.

[0170] <Step of cleaning substrate: cleaning step>

[0171] This process is a process of etching the substrate using the treatment liquid of the first scheme. This process includes an operation of bringing the cleaning liquid into contact with the substrate. The method of the cleaning method is not particularly limited, and a known cleaning method can be used. As this method, for example, a method of continuously applying the cleaning liquid on a substrate rotating at a certain speed (spin coating method), a method of immersing the substrate in the cleaning liquid for a certain period of time (immersion method), a method of spraying the cleaning liquid on the surface of the substrate (spraying method), etc. can be cited.

[0172] The above-mentioned cleaning step may be performed only once or twice or more. When cleaning is performed twice or more, the same cleaning method may be repeated or different cleaning methods may be combined.

[0173] The temperature for the cleaning treatment is not particularly limited. Examples of the cleaning treatment temperature include 15 to 70° C., 20 to 70° C., 30 to 65° C., or 40 to 65° C. The cleaning performance is improved by increasing the temperature of the treatment liquid. However, the temperature of the cleaning liquid can be appropriately selected in consideration of suppressing the composition change of the cleaning liquid to a minimum, workability, safety, cost, etc.

[0174] The cleaning time can be appropriately selected to be a time sufficient to remove impurities, residues, etc. on the substrate surface. Examples of the cleaning time include 10 seconds to 30 minutes, 20 seconds to 15 minutes, 30 seconds to 10 minutes, or 30 seconds to 5 minutes.

[0175] The cleaning solution of the first aspect can be diluted 2 to 2000 times to obtain a diluted solution when used. In this step, the substrate can be cleaned using the diluted solution.

[0176] <Substrate>

[0177] The substrate to be cleaned may be the same substrate as the substrate described as the application target of the cleaning solution in the first embodiment. The substrate may also be a substrate after dry etching of a layer containing a metal (molybdenum, tungsten, etc.) by a wiring process (for example, Figure 1 ). The substrate may be, for example, a substrate after dry etching of the wiring layer by a semi-damascene process. In addition, the substrate may be a substrate after dry etching of a Si-containing layer (e.g., a Si-containing insulating film) by a wiring process, exposing metal (molybdenum, tungsten, etc.). In addition, the substrate may be a substrate after a CMP process in a wiring process, exposing metal (molybdenum, tungsten, etc.). In particular, when the CMP slurry contains Si-based fillers, cleaning with the cleaning solution of the first scheme is useful.

[0178] <Optional process>

[0179] The method of this embodiment may include any process other than the above-mentioned cleaning process, such as a hard mask layer etching process, a wiring layer dry etching process, a CMP (Chemical Mechanical Polishing) process, a contact etching process, etc.

[0180] (Hard Mask Layer Etching Process)

[0181] The method of this embodiment may include a hard mask layer etching step before the cleaning step. The hard mask layer etching step is a step of etching the hard mask layer. As a material of the hard mask layer, for example, silicon dioxide (SiO 2 ), silicon nitride (Si 3 N 4 ) and silicon oxynitride (SiON), etc. As a method for forming the hard mask layer, for example, CVD, ALD, PVD, etc. can be mentioned.

[0182] The hard mask layer can be etched by, for example, using a resist pattern as a mask. The hard mask layer can be etched by, for example, dry etching. As an etching gas, a mixture of oxygen and a halogen gas can be cited. As a halogen-containing gas, tetrafluoromethane (CF 4 ) gas, trifluoromethane (CHF 3 ) gas and other fluorinated carbon gases; chlorine (Cl 2 ) gas and other chlorine gases, etc.

[0183] (Wiring layer dry etching process)

[0184] The method of this embodiment may also include a wiring layer dry etching step before the cleaning step. The wiring layer dry etching step is a step of performing dry etching of the wiring layer. In the method of this embodiment, the wiring layer contains at least one metal selected from the group consisting of molybdenum and tungsten. As a method for forming the wiring layer, for example, CVD, ALD, PVD, etc. can be cited.

[0185] The wiring layer can be etched using, for example, a hard mask pattern to which a resist pattern is transferred as a mask. The wiring layer can be dry-etched using, for example, oxygen gas, chlorine gas, or the like as an etching gas.

[0186] (CMP process)

[0187] The method of this embodiment may also include a CMP process. The CMP process is a process of performing CMP treatment on the substrate. By performing the CMP process, the surface of the substrate can be flattened. The CMP process can be performed after the pad layer and the wiring layer are formed on the substrate in order to flatten the wiring layer.

[0188] For example, a low-k layer is formed on the substrate, and grooves and through holes are formed in the low-k layer. Then, a pad layer is formed, and then a wiring layer is formed. Next, the substrate surface is flattened by CMP. After CMP, shavings including oxides of metals from the wiring layer are attached to the substrate, but by performing the above-mentioned cleaning process, the shavings can be removed while suppressing corrosion.

[0189] (Contact and through-hole forming process)

[0190] The method of this embodiment may include a Si-based insulating film dry etching step for forming a contact hole or a through hole before the cleaning step. The Si-based insulating film is made of SiO 2 , SiOC, SiC, SiN film or other Si-containing film. In addition, a layer containing SiN, SiCN, SiCO or Al may be formed under the Si-based insulating film forming the contact or through hole. 2 O 3 After dry etching, metal wiring (molybdenum wiring, tungsten wiring, etc.) is exposed at the bottom of the contact or through hole. As a method for forming the wiring layer, for example, CVD, ALD, PVD, etc. can be cited.

[0191] The method of this embodiment may further include a hard mask removal step, a dielectric layer formation step, a polishing step, an etching stop layer formation step, etc. after the cleaning step in addition to the above-mentioned steps.

[0192] According to the method of this embodiment, since the cleaning liquid of the first embodiment is used to clean the substrate, in a substrate where metal is exposed on the surface, etching residues containing silicon and the like can be cleaned without damaging the metal. Therefore, the method of this embodiment can be suitably applied to a substrate after dry etching of a metal-containing layer (e.g., a tungsten wiring layer or a molybdenum wiring layer) by a wiring process.

[0193] Example

[0194] Hereinafter, the present invention will be described in further detail by way of Examples, but the present invention is not limited to these Examples.

[0195] <Preparation of cleaning solution>

[0196] (Examples 1 to 24, Comparative Examples 1 to 29)

[0197] The components shown in Tables 1 to 20 were mixed to prepare cleaning solutions of respective examples.

[0198] [Table 1]

[0199]

[0200] [Table 2]

[0201]

[0202] [Table 3]

[0203]

[0204] [Table 4]

[0205]

[0206] [Table 5]

[0207]

[0208] [Table 6]

[0209]

[0210] [Table 7]

[0211]

[0212] [Table 8]

[0213]

[0214] [Table 9]

[0215]

[0216] [Table 10]

[0217]

[0218] [Table 11]

[0219]

[0220] [Table 12]

[0221]

[0222] [Table 13]

[0223]

[0224] [Table 14]

[0225]

[0226] [Table 15]

[0227]

[0228] [Table 16]

[0229]

[0230] [Table 17]

[0231]

[0232] [Table 18]

[0233]

[0234] [Table 19]

[0235]

[0236] [Table 20]

[0237]

[0238] In Tables 1 to 20, each abbreviation has the following meaning. The numerical value in [ ] indicates the mass % relative to the total mass of the cleaning solution. The numerical value in ( ) in component (B) indicates the molar concentration (mol / L) of component (B) in the cleaning solution. [Appropriate amount] in component (C) indicates the amount added to adjust the pH of the cleaning solution to a predetermined pH.

[0239] "pH" represents the pH of the cleaning solution at 23°C. The pH is measured using a pH meter (portable pH meter D-73S, Horiba, Ltd.).

[0240] "pH-pI" represents the value obtained by subtracting the isoelectric point (pI) of component (A1) from the pH of the cleaning solution at 23°C.

[0241] From the pH of the cleaning solutions shown in Tables 2 to 17, it can be seen that in any of the cleaning solutions of Examples 1 to 24, the pH of the cleaning solution and the isoelectric point (pI) of component (A1) satisfy the relationship of the above formula (1).

[0242] <Alkaline compound: Component (B)>

[0243] TMAH: Tetramethylammonium hydroxide

[0244] MEA: Monoethanolamine

[0245] AEEA: 2-(2-Aminoethylamino)ethanol

[0246] NH 2 OH: Hydroxylamine

[0247] NH 3 : Ammonia

[0248] DBU: 1,8-Diazabicyclo[5.4.0]undec-7-ene

[0249] <Amino acid: Component (A1)>

[0250] Arg: Arginine (isoelectric point: 10.76)

[0251] Lys: Lysine (isoelectric point: 9.74)

[0252] Gly: Glycine (isoelectric point: 5.97)

[0253] Cys: Cysteine (isoelectric point: 5.07)

[0254] His: Histidine (isoelectric point: 7.59)

[0255] <Chelating agent: Component (A2)>

[0256] TA: Tartaric acid

[0257] IDA: Iminodiacetic acid

[0258] <Solvent: Component (S)>

[0259] EG: Ethylene glycol

[0260] <pH regulator>

[0261] CA: Citric acid

[0262] [Evaluation of anti-corrosion performance]

[0263] The corrosion resistance of the cleaning solution to metal wiring was evaluated by the etching rate of molybdenum.

[0264] <Measurement of Molybdenum Etching Rate>

[0265] As a substrate, a substrate on which a molybdenum film (50 nm) was formed on a 12-inch silicon substrate by the PVD method was used. The substrate was cut into 2 cm×2 cm to make a wafer specimen. 100 mL of the cleaning solution of each example was added to a 200 mL beaker, heated to 60°C, and the wafer specimen was immersed in the cleaning solution. During the immersion of the wafer specimen, it was stirred at 60°C and 300 rpm. After immersion for 10 minutes, the wafer specimen was taken out of the cleaning solution, washed with water at room temperature for 30 seconds, and dried by blowing with nitrogen.

[0266] The film thickness of the wafer specimens before and after immersion in the cleaning solution was measured. The film thickness was measured using a fluorescent X-ray device (ZSX Primus IV, Rigaku). The etching rate was calculated based on the change in the film thickness of the molybdenum film before and after the cleaning process. The results are shown in Tables 21 to 40 as "Mo ER".

[0267] <Evaluation of Anticorrosion Performance>

[0268] The molybdenum etching rate (Mo ER 0 ) as a benchmark, evaluate the corrosion resistance of component (A1) or component (A2). The reference comparative example of each example is recorded in the first line of each table. Calculate the molybdenum etching rate (Mo ER) of each example divided by the molybdenum etching rate (Mo ER) of the reference comparative example. 0 The result is referred to as "Mo ER / Mo ER 0 ” are shown in Tables 21 to 40.

[0269] The anticorrosion performance was evaluated based on the following evaluation criteria. The results are shown in Tables 21 to 40 as "Anticorrosion Performance".

[0270] Evaluation Benchmarks

[0271] A: Mo ER / Mo ER 0 Less than 0.5 and Mo ER less than

[0272] D: Mo ER / Mo ER 0 is 0.5 or more or Mo ER is above

[0273] [Evaluation of cleaning performance]

[0274] The cleaning performance of the cleaning solution is evaluated by the etching rate of amorphous silicon, which is a component contained in the residue after dry etching of metal wiring.

[0275] <Measurement of Amorphous Silicon Etching Rate>

[0276] As a substrate, a substrate on which an amorphous silicon film (100 nm) is formed by the PVD method on a 12-inch silicon substrate is used. The substrate is cut into 2 cm×2 cm to make a wafer specimen. 100 mL of the cleaning solution of each example is added to a 200 mL beaker, heated to 60°C, and the wafer specimen is immersed in the cleaning solution. During the immersion of the wafer specimen, it is stirred at 60°C and 300 rpm. After immersion for 10 minutes, the wafer specimen is taken out of the cleaning solution, washed with water at room temperature for 30 seconds, and dried by blowing with nitrogen.

[0277] The film thickness of the wafer sample was measured before and after immersion in the cleaning solution. Ellipsometer (M-2000, JA Woolam) was used to measure the film thickness. The etching rate (aSi ER) was calculated based on the change in the film thickness of the amorphous silicon film before and after the cleaning process.

[0278] <Evaluation of cleaning performance>

[0279] The amorphous silicon etching rate (aSi ER) of each example relative to the amorphous silicon etching rate (aSi ER) of the reference comparative example recorded in the first row of each table was calculated by the following formula: 0 )’s rate of change (CR).

[0280] CR(%)=[aSi ER 0 -aSi ER] / aSi ER 0 ×100

[0281] The cleaning performance was evaluated based on the following evaluation criteria. The results are shown in Tables 21 to 40 as "cleaning performance".

[0282] Evaluation Benchmarks

[0283] A: aSi ER is 30nm / min or more

[0284] B: aSi ER is 10nm / min or more and less than 30nm / min

[0285] C: aSi ER less than 10nm / min and CR less than 10%

[0286] D: aSi ER is less than 10nm / min and CR is 10% or more [Table 21]

[0287]

[0288] [Table 22]

[0289]

[0290] [Table 23]

[0291]

[0292] [Table 24]

[0293]

[0294] [Table 25]

[0295]

[0296] [Table 26]

[0297]

[0298] [Table 27]

[0299]

[0300] [Table 28]

[0301]

[0302] [Table 29]

[0303]

[0304] [Table 30]

[0305]

[0306] [Table 31]

[0307]

[0308] [Table 32]

[0309]

[0310] [Table 33]

[0311]

[0312] [Table 34]

[0313]

[0314] [Table 35]

[0315]

[0316] [Table 36]

[0317]

[0318] [Table 37]

[0319]

[0320] [Table 38]

[0321]

[0322] [Table 39]

[0323]

[0324] [Table 40]

[0325]

[0326] According to the results in Tables 21 to 40, the cleaning solutions of Examples 1 to 24 have significantly improved anticorrosion performance while maintaining good cleaning performance compared to the reference comparative examples. On the other hand, the anticorrosion performance of the comparative examples cannot be said to be sufficiently improved compared to the reference comparative examples.

[0327] From these results, it was confirmed that the cleaning liquids of Examples 1 to 24 satisfying the relationship of the above-mentioned formula (1) can well clean the dry etching residue while suppressing damage to the metal wiring.

[0328] From the results of Comparative Examples 20 and 21, it was confirmed that when a nitrogen heterocyclic compound was contained, the anticorrosion effect of the component (A1) could not be fully exhibited.

[0329] From the results of Comparative Examples 24 to 27, it was confirmed that the anticorrosion effect of the component (A1) could not be fully exhibited when the component (B) was contained in an amount of 12 mass % or more.

[0330] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, omissions, substitutions and other changes to the configuration can be made without departing from the gist of the present invention. The present invention is not limited by the above description, but only by the scope of the appended claims.

[0331] Description of Reference Numerals

[0332] 1 substrate

[0333] 10 wiring layers

[0334] 20Hard mask layer

[0335] 30Low-k layer

[0336] 40 residues.< / ph>

Claims

1. A cleaning liquid for cleaning a substrate with metal exposed on the surface, It is characterized in that Include: Basic compounds, Amino acids, and water, The isoelectric point (pI) of the amino acid and the pH of the cleaning solution at 23° C. satisfy the following formula (1), pI-2 <pH<pI+2(1) The cleaning solution does not contain nitrogen heterocyclic compounds, The concentration of the alkaline compound is less than 12% by mass relative to the total mass of the cleaning liquid.

2. The cleaning solution according to claim 1, It is characterized in that The basic compound has a pH of 7.5 or higher at 23° C. when prepared as a 0.01 M aqueous solution.

3. The cleaning solution according to claim 1 or 2, It is characterized in that The isoelectric point of the amino acid is 7 or above.

4. The cleaning solution according to claim 1 or 2, It is characterized in that The pH of the cleaning solution is 9 or more at 23°C.

5. The cleaning solution according to claim 1 or 2, It is characterized in that The concentration of the basic compound is 1% by mass or less relative to the total mass of the cleaning liquid.

6. The cleaning solution according to claim 1 or 2, It is characterized in that The concentration of the amino acid is 0.5 mass % or less relative to the total mass of the cleaning liquid.

7. The cleaning solution according to claim 1 or 2, It is characterized in that The present invention further comprises at least one selected from the group consisting of a buffer, an anticorrosive agent, a surfactant, and an organic solvent.

8. The cleaning solution according to claim 1 or 2, It is characterized in that The substrate is a substrate after dry etching or CMP of the metal has been performed.

9. The cleaning solution according to claim 1 or 2, It is characterized in that The metal is molybdenum or tungsten.

10. A method for cleaning a substrate, It is characterized in that The method comprises the step of using the cleaning solution according to claim 1 or 2 to clean a substrate having metal exposed on the surface.

11. The method for cleaning a substrate according to claim 10, It is characterized in that The substrate is a substrate after dry etching or CMP of the metal has been performed.

12. The method for cleaning a substrate according to claim 10, It is characterized in that The metal is molybdenum or tungsten.

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