Cleaning solution, semiconductor substrate cleaning method, and method for manufacturing semiconductor

Abstract

To provide a cleaning solution that can efficiently remove titanium residues and has excellent anti-corrosion properties, and a semiconductor substrate cleaning method and a method for manufacturing a semiconductor using this solution.SOLUTION: A cleaning solution having an acid dissociation constant pKa of less than 5.0, containing more than divalent oxoacids, and a pH value less than the acid dissociation constant, a semiconductor substrate cleaning method using the same, and a method for manufacturing the semiconductor are provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cleaning solution, a method for cleaning a semiconductor substrate, and a method for manufacturing a semiconductor. [Background technology]

[0002] In the wiring formation process, for example, a hard mask layer (HM layer) is formed on an interlayer insulating film in which a substrate, a metal wiring layer, and an interlayer insulating film such as a silicon-based insulating film are laminated in this order, and then the hard mask layer is etched to form a prototype of the wiring pattern. Examples of materials for the mask layer include titanium, titanium nitride (TiN), and titanium oxide (TiO x Titanium-based alloys such as (x represents a number) are used.

[0003] Next, the interlayer insulating film is dry etched using the etched HM layer as a mask layer to form a wiring pattern such as metal wiring.

[0004] Furthermore, after dry etching, the element (e.g., substrate / metal wiring layer / interlayer insulating film / HM layer) contains titanium-based residues (residues containing titanium or titanium-based alloys) derived from the HM layer and inorganic-containing residues derived from the metal wiring layer.

[0005] Dry etching residues have conventionally been removed by a cleaning process. As a cleaning solution for removing dry etching residues, a cleaning solution containing a peroxide as a residue remover is used (see, for example, Patent Document 1). In addition, a cleaning solution containing hydroxylamine as a residue remover, a cleaning solution containing hydrogen fluoride, etc. are used. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2016 / 076033 Summary of the Invention [Problem to be solved by the invention]

[0007] The present inventors have conducted detailed studies on components commonly used in cleaning solutions, such as hydrogen peroxide, hydrogen fluoride, hydroxylamine, etc. As a result, they have unexpectedly found that cleaning solutions containing these as their main components have room for improvement in terms of both removing titanium-based residues (residues containing titanium or titanium-based alloys) and providing corrosion resistance.

[0008] Furthermore, as a result of various investigations into components other than those mentioned above that are used in the cleaning solution, it was found that there was still room for improvement in terms of achieving both the removal of titanium-based residues and corrosion prevention properties.

[0009] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a cleaning solution that can efficiently remove titanium-based residues and has excellent anticorrosive properties, as well as a method for cleaning semiconductor substrates using the same, and a method for manufacturing semiconductors. [Means for solving the problem]

[0010] As a result of intensive research into achieving the above-mentioned object, the present inventors have discovered that a cleaning solution has an acid dissociation constant pKa of less than 5.0, contains a divalent or higher oxoacid, and has a pH value smaller than the acid dissociation constant, and have thus completed the present invention.

[0011] [1] A cleaning solution having an acid dissociation constant pKa of less than 5.0, containing a divalent or higher oxoacid, and having a pH value smaller than the acid dissociation constant. [2] The cleaning solution according to [1], having a pH of 5.0 or less. [3] The cleaning solution according to [1], wherein the oxoacid is at least one selected from the group consisting of oxalic acid, malonic acid, H3PO4, and sulfuric acid. [4] The cleaning solution according to [1], wherein the concentration of the oxoacid is 0.005 to 20% by mass. [5] The cleaning solution according to [1], further comprising, as a corrosion inhibitor, at least one selected from the group consisting of a nitrogen-containing heterocycle-containing compound, a mercapto group-containing compound, an aliphatic amine compound, a zwitterionic compound, and a salt thereof. [6] The cleaning solution according to [1], further comprising water as a solvent. [7] The cleaning solution according to [1], further comprising at least one solvent selected from the group consisting of alcohol-based solvents, glycol ester-based solvents, sulfoxide-based solvents, sulfone-based solvents, amide-based solvents, lactone-based solvents, imidazolidinone-based solvents, nitrile-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, pyrrolidone-based solvents, and urea-based solvents. [8] The cleaning solution according to [1], which does not contain hydrogen peroxide, hydrogen fluoride, or hydroxylamine. [9] The cleaning liquid is a cleaning liquid for a semiconductor substrate, the semiconductor substrate including a substrate and a film formed on the substrate, the film containing titanium or a titanium-based alloy, the cleaning liquid according to [1].

[10] A method for cleaning a semiconductor substrate having a protective film, comprising the step of removing impurities from the semiconductor substrate by contacting the protective film with the cleaning solution described in [1].

[11] A method for manufacturing a semiconductor, comprising the steps of: preparing a substrate having a protective film; etching the protective film; and, after the etching, removing impurities from the substrate by contacting the substrate with the cleaning solution described in [1]. Effect of the Invention

[0012] According to the present invention, it is possible to provide a cleaning solution which can efficiently remove titanium-based residues and has excellent anticorrosive properties, as well as a method for cleaning a semiconductor substrate and a method for manufacturing a semiconductor using the same. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view showing an example of an element to be cleaned after dry etching. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment for carrying out the present invention (hereinafter, simply referred to as "the present embodiment") will be described in detail. The present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist.

[0015] In the drawings, the same elements are given the same reference numerals, and duplicated explanations are omitted. Furthermore, unless otherwise specified, the positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the ratios shown in the drawings.

[0016] <Cleaning solution>

[0017] The cleaning solution according to this embodiment has an acid dissociation constant pKa of less than 5.0, contains a divalent or higher oxoacid, and has a pH value smaller than the acid dissociation constant. By using a cleaning solution that satisfies these conditions, titanium-based residues can be efficiently removed and excellent corrosion prevention properties can be achieved. Note that titanium-based residues refer to residues that contain titanium or titanium-based alloys. Titanium-based alloys refer to titanium, which is a metal, bonded with other metal elements or nonmetal elements. As will be described in detail later, titanium-based alloys include, for example, titanium nitride (TiN), titanium oxide (TiO x (x represents a number), titanium oxynitride (TiON), titanium oxyfluoride (TiOF), and the like.

[0018] The cleaning solution according to the present embodiment can be suitably used as a cleaning solution for removing etching residues containing inorganic substances. In this case, the cleaning solution can be suitably used as a cleaning solution for semiconductor cleaning, etc.

[0019] The inorganic substance referred to here is a compound containing a metal, and examples thereof include metals, metal oxides, metal nitrides, metal chlorides, and metal fluorides. Examples of inorganic substances other than metals include silicon (Si) and its oxides. That is, the cleaning solution according to this embodiment can efficiently remove etching residues containing such inorganic substances.

[0020] More specifically, the cleaning solution according to the present embodiment can efficiently remove titanium-based residues (residues containing titanium or titanium-based alloys) contained in the HM layer and other layers. In addition, the cleaning solution according to the present embodiment is expected to efficiently remove inorganic-containing residues derived from the metal wiring layer, including metals described below, and one selected from the group consisting of metal oxides, metal nitrides, metal chlorides, and metal fluorides of these metals.

[0021] Examples of metals include molybdenum (Mo), tungsten (W), ruthenium (Ru), copper (Cu), gold (Au), silver (Ag), iron (Fe), nickel (Ni), aluminum (Al), lead (Pb), zinc (Zn), tin (Sn), tantalum (Ta), magnesium (Mg), cobalt (Co), bismuth (Bi), cadmium (Cd), titanium (Ti), zirconium (Zr), antimony (Sb), manganese (Mn), beryllium (Be), chromium (Cr), germanium (Ge), vanadium (V), gallium (Ga), hafnium (Hf), indium (In), niobium (Nb), rhenium (Re), and thallium (Tl), as well as metal oxides, metal nitrides, metal chlorides, and metal fluorides thereof.

[0022] Examples of the metal oxide include metal oxides of the above-mentioned metal atoms. Specific examples of the metal oxide include TiO x , TaO x , CuO x , CoO x , RuO x , AlO x , WO x , MoO x , AuO x , AgOx , FeO x , NiO x (Unless otherwise specified, x represents a number.) etc., but are not limited to these.

[0023] The metal nitride may be any of the metal nitrides of the above-mentioned metal atoms. Specific examples of metal nitrides include TiN. x ,TaN x , CuN x , CoN x , RuN x , AlN x , W.N. x , MoN x , AuN x , AgN x , FeN x , NiN x These include, but are not limited to, the following.

[0024] The metal chlorides include metal chlorides of the above-mentioned metal atoms. Specific examples of metal chlorides include TiCl x , TaCl x , CuCl x , CoCl x , RuCl x , AlCl x , WCl x , MoCl x , AuCl x , AgCl x , FeCl x , NiCl x These include, but are not limited to, the following.

[0025] The metal fluoride may be a metal fluoride of the above-mentioned metal atoms. Specific examples of the metal fluoride include TiF x , TaF x , CuF x , CoF x , RuF x , AlF x , W.F. x , MoF x , AuF x , AgF x , FeF x , NiFx These include, but are not limited to, the following.

[0026] The cleaning solution according to the present embodiment is suitable for removing etching residues, and is particularly suitable for removing dry etching residues. In general, dry etching residues are removed before the next process in order to improve semiconductor yields and prevent deterioration of electrical characteristics. For example, the cleaning solution according to the present embodiment is suitable for cleaning semiconductor substrates after dry etching in a wiring process.

[0027] For example, the cleaning solution according to the present embodiment can effectively remove residues containing titanium or titanium-based alloys derived from the HM layer and etching residues containing inorganic substances derived from the metal wiring layer that adhere during the wiring process. In particular, titanium-based residues that adhere to the semiconductor substrate after dry etching have high wet resistance and are difficult to remove by cleaning treatment. The cleaning solution according to the present embodiment can efficiently clean such residues.

[0028] (Oxoacid)

[0029] The "oxoacid" contained in the cleaning solution according to this embodiment refers to a compound having a hydroxyl group (-OH) capable of donating a proton. The valence of an oxoacid refers to the number of protons that can be donated (released) from the molecule. In this embodiment, a divalent or higher oxoacid is used.

[0030] The reason why the cleaning solution according to this embodiment can efficiently remove titanium-based residues is not clear, but is presumed to be as follows. The oxoacid contained in the cleaning solution can have a strong interactive force with the titanium atoms contained in the residues, and therefore the oxoacid can hold the titanium atoms. As a result, it is presumed that the cleaning solution can efficiently remove titanium-based residues (however, the action of this embodiment is not limited to this).

[0031] The valence of the oxoacid may be two or more. The upper limit of the valence of the oxoacid is not particularly limited, but is preferably five or less, more preferably four or less, and even more preferably three or less. These valences allow the titanium-based residue to be removed more efficiently. The reason is unclear, but is presumed to be as follows. When an oxoacid having the above-mentioned specific pKa value is present in a cleaning solution having the above-mentioned specific pH value, it is believed that the valence of the oxoacid increases the above-mentioned interaction force with titanium atoms. As a result, it is presumed that the oxoacid can hold titanium atoms more reliably, and the cleaning solution can remove titanium-based residues more efficiently (however, the action of this embodiment is not limited to these).

[0032] Specific examples of oxoacids include carboxylic acids, boric acid (HBO, B(OH)), carbonic acid (HCO), orthocarbonic acid (HCO, C(OH)CHO), carboxylic acid, halogen oxoacids (hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodous acid, iodous acid, iodic acid, periodic acid, etc.), silicic acid, nitrous acid (HNO), nitric acid, phosphoric acid (HPO, HPO, HPO), phosphorous acid (HPO), sulfuric acid, sulfurous acid, sulfonic acids, sulfinic acids, etc. The cleaning solution according to this embodiment may contain salts of these oxoacids (e.g., sodium salt, potassium salt, calcium salt, barium salt, ammonium salt, tetraalkylammonium salt, etc.).

[0033] Carboxylic acids are acids having at least one carboxy group (-COOH). Specific examples of carboxylic acids include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, and valeric acid; dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid; and tricarboxylic acids such as citric acid.

[0034] Examples of halogen oxoacids include hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodous acid, iodous acid, iodic acid, and periodic acid.

[0035] Sulfonic acids are acids having at least one sulfo group (-SO3H). Specific examples of sulfonic acids include methanesulfonic acid, trifluorosulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid.

[0036] Among the above oxoacids, at least one selected from the group consisting of carboxylic acids, phosphoric acid (H3PO4, H4P2O7, HPO3), phosphorous acid (H3PO3), sulfuric acid, sulfurous acid, and nitric acid is preferred; at least one selected from the group consisting of carboxylic acids, phosphoric acid (H3PO4, H4P2O7, HPO3), sulfuric acid, and nitric acid is more preferred; and the oxoacid is still more preferably at least one selected from the group consisting of oxalic acid, malonic acid, H3PO4, and sulfuric acid.

[0037] In the cleaning solution according to this embodiment, the above-mentioned oxoacids may be used alone or in combination of two or more kinds.

[0038] The acid dissociation constant of the oxoacid may be less than 5.0. The upper limit of the acid dissociation constant is preferably 5.0 or less, more preferably 3.0 or less. The lower limit of the acid dissociation constant is not particularly limited, but is preferably -5.0 or more, more preferably -3.0 or more.

[0039] In this embodiment, the term "acid dissociation constant" refers to an index that indicates the acid strength of a substance, and refers to the acid dissociation constant (pKa) in water at 22°C. For example, in the case of a parallel dissociation reaction represented by the following formula (i), the acid dissociation constant is expressed as Ka = [H + ][A - ] / [HA], and pKa=-log 10pKa represents the value of Ka. In the case of a substance that undergoes multi-stage dissociation of two or more stages, the first stage of dissociation (initial dissociation) is considered. The pKa value in this embodiment is calculated using the "Sparc Calculator" (archemcalc.com) operated on the Internet by Archem, Inc. (Reference URL: http: / / archemcalc.com / sparc-web / calc# / multiproperty) It can be calculated by:

[0040] [ka]

[0041] In this embodiment, when two or more oxoacids are used in combination, a weighted average value is adopted, which is calculated by multiplying the acid dissociation constant of each oxoacid by the content ratio (mass ratio) of the oxoacids. For example, in a cleaning solution containing oxoacid A:oxoacid B in a content ratio of 3:1, if the acid dissociation constant of oxoacid A is 2.0 and the acid dissociation constant of oxoacid B is 1.0, Weighted average of acid dissociation constants = 2.0 x (3 / 4) + 1.0 x (1 / 4) = 1.75 It becomes.

[0042] Table 1 below shows, as an example, the acid dissociation constants of oxoacids calculated using the online "Sparc Calculator" (archemcalc.com) operated by Archem (the oxoacids that can be used in this embodiment are not limited to the ones listed below).

[0043] [Table 1]

[0044] The pH value of the cleaning solution according to the present embodiment is smaller than the acid dissociation constant. The upper limit of the pH value is not particularly limited, but is preferably 5.0 or less, more preferably less than 5.0, and even more preferably less than 4.9. The lower limit of the pH value is not particularly limited, but is preferably -5 or more, more preferably -3 or more, even more preferably -1 or more, and even more preferably a value greater than 0.

[0045] In addition, the pH value of the cleaning solution in this embodiment refers to the value of the cleaning solution at normal pressure (1 atmospheric pressure) and 22° C. The pH value can be measured, for example, by the method described in the examples below.

[0046] The concentration of the oxoacid in the cleaning solution according to this embodiment is not particularly limited, but is preferably 0.005 to 20% by mass. The upper limit of the oxoacid concentration is more preferably 18% by mass or less, and even more preferably 15% by mass or less. The lower limit of the oxoacid concentration is more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more. When the content of the oxoacid is equal to or greater than the above lower limit, the removability of dry etching residues in the cleaning process can be further improved. On the other hand, when the content of the oxoacid is equal to or less than the above upper limit, damage to metal wiring and the like can be further suppressed.

[0047] It is preferable that the cleaning solution according to the present embodiment does not contain hydrogen peroxide. Also, it is preferable that the cleaning solution according to the present embodiment does not contain hydrogen fluoride. In addition, it is preferable that the cleaning solution according to the present embodiment does not contain hydroxylamine. From this viewpoint, it is more preferable that the cleaning solution according to the present embodiment does not contain hydrogen peroxide, hydrogen fluoride, and hydroxylamine.

[0048] From the above viewpoint, it is preferable that the cleaning liquid according to this embodiment does not contain hydrofluoric acid (aqueous solution of hydrogen fluoride), hydrogen peroxide solution (aqueous solution of hydrogen peroxide), or the like.

[0049] The cleaning solution according to the present embodiment is expected to obtain a predetermined effect even if it does not contain any component other than oxoacid. Therefore, the cleaning solution according to the present embodiment may or may not contain any component other than oxoacid as necessary. For example, it is preferable that the cleaning solution further contains an anticorrosive agent. In addition to the anticorrosive agent, the cleaning solution may further contain a pH adjuster, a surfactant, a solvent, etc., but since sufficient effects can be expected even without these, they may not be contained. In addition, the cleaning solution according to the present embodiment may contain metal impurities, which will be described later, as long as the action and effect can be obtained.

[0050] (Corrosion inhibitor)

[0051] Specific examples of the anticorrosive agent include, but are not limited to, at least one selected from the group consisting of nitrogen-containing heterocycle-containing compounds, mercapto group-containing compounds, aliphatic amine compounds, zwitterionic compounds, and salts thereof. The cleaning solution according to the present embodiment preferably contains one selected from such a group.

[0052] Specific examples of the nitrogen-containing heterocycle-containing compound include imidazole ring-containing compounds, triazole ring-containing compounds, pyridine ring-containing compounds, pyrimidine ring-containing compounds, phenanthroline ring-containing compounds, tetrazole ring-containing compounds, pyrazole ring-containing compounds, and purine ring-containing compounds. Among these, tetrazole ring-containing compounds are preferred. By using a tetrazole ring-containing compound, the corrosion resistance of a layer containing, for example, a metal component such as cobalt or copper as a main component (for example, the metal wiring layer 20, the etching stop layer 30, the interlayer insulating film 40, or other functional layers, etc.) can be further improved. That is, when the cleaning solution according to this embodiment is used, the damage (film loss) given to the layer containing cobalt, copper, etc. can be further effectively reduced.

[0053] Specific examples of the imidazole ring-containing compound include 1-decyl-3-methylimidazolium chloride, 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-propylimidazole, 2-butylimidazole, 4-methylimidazole, 2,4-dimethylimidazole, 2-undecylimidazole, 2-aminoimidazole, and 2,2'-biimidazole.

[0054] Specific examples of the triazole ring-containing compound include 1,2,4-triazole, 1,2,3-benzotriazole, 1,2,3-triazole, 3-amino-1H-1,2,4-triazole, 5-methyl-1H-benzotriazole, 1-hydroxybenzotriazole, 1-dihydroxypropylbenzotriazole, 2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole, 4-carboxyl-1H-benzotriazole methyl ester, 4-carboxyl-1H-benzotriazole butyl ester, 4-carboxyl-1H-benzotriazole octyl ester, 5-hexylbenzotriazole, [1,2,3-benzotriazolyl-1-methyl][1,2,4-triazolyl-1-methyl][2-ethylhexyl]amine, tolyltriazole, naphthotriazole, bis[(1-benzotriazolyl)methyl]phosphonic acid, and 3-aminotriazole.

[0055] Specific examples of the pyridine ring-containing compound include 1H-1,2,3-triazolo[4,5-b]pyridine, 1,2,4-triazolo[4,3-a]pyridin-3(2H)-one, 3H-1,2,3-triazolo[4,5-b]pyridin-3-ol, 1-acetyl-1H-1,2,3-triazolo[4,5-b]pyridine, 3-aminopyridine, 4-aminopyridine, 3-hydroxypyridine, 4-hydroxypyridine, 2-acetamidopyridine, 4-pyrrolidinopyridine, 2-cyanopyridine, 2,2'-bipyridyl, 4,4'-dimethyl-2,2'-bipyridyl, 4,4'-di-tert-butyl-2,2'-bipyridyl, and 4,4-dinonyl-2,2-bipyridyl.

[0056] Specific examples of the pyrimidine ring-containing compound include pyrimidine, 1,2,4-triazolo[1,5-a]pyrimidine, 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine, 1,3-diphenyl-pyrimidine-2,4,6-trione, 1,4,5,6-tetrahydropyrimidine, 2,4,5,6-tetraaminopyrimidine sulfate, 2,4,5-trihydroxypyrimidine, 2,4,6-triaminopyrimidine, 2,4,6-trichloropyrimidine, 2,4,6-trimethoxypyrimidine, 2,4,6-triphenyl ... Phenylpyrimidine, 2,4-diamino-6-hydroxylpyrimidine, 2,4-diaminopyrimidine, 2-acetamidopyrimidine, 2-aminopyrimidine, 2-methyl-5,7-diphenyl-(1,2,4)triazolo(1,5-a)pyrimidine, 2-methylsulfanyl-5,7-diphenyl-(1,2,4)triazolo(1,5-a)pyrimidine, 2-methylsulfanyl-5,7-diphenyl-4,7-dihydro-(1,2,4)triazolo(1,5-a)pyrimidine, 4-aminopyrazolo[3,4-d]pyrimidine, and the like.

[0057] A specific example of the phenanthroline ring-containing compound is 1,10-phenanthroline.

[0058] Specific examples of the tetrazole ring-containing compound include 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 1-(2-diaminoethyl)-5-mercaptotetrazole, and the like.

[0059] Specific examples of the pyrazole ring-containing compound include 3,5-dimethylpyrazole, 3-amino-5-methylpyrazole, 4-methylpyrazole, and 3-amino-5-hydroxypyrazole.

[0060] Specific examples of purine ring-containing compounds include purine.

[0061] Specific examples of mercapto group-containing compounds include 1-thioglycerol, 3-(2-aminophenylthio)-2-hydroxypropyl mercaptan, 3-(2-hydroxyethylthio)-2-hydroxypropyl mercaptan, 2-mercaptopropionic acid, and 3-mercaptopropionic acid.

[0062] Specific examples of the aliphatic amine compound include alkylamines, dialkylamines, and trialkylamines.

[0063] Specific examples of zwitterionic compounds include compounds that contain a cationic moiety such as a tertiary amine or a quaternary amine, and an anionic moiety such as a sulfonic acid group or a carboxyl group. + -CHR´-SO3 - (where R represents a monovalent hydrocarbon group and R' represents a divalent hydrocarbon group), and zwitterionic compounds represented by R + -CHR´-COO - (R represents a monovalent hydrocarbon group, and R' represents a divalent hydrocarbon group.) and the like. For example, carbobetaine, sulfobetaine, etc. can be used as the zwitterionic compound.

[0064] The anticorrosive agent may be a salt of the above-mentioned compound. Specific examples of the salt include, but are not limited to, sodium salt, potassium salt, ammonium salt, alkylammonium salt (e.g., tetramethylammonium salt, etc.), etc. The anticorrosive agent may also be a hydrate of the above-mentioned compound.

[0065] Also, from another viewpoint, preferred examples include at least one selected from the group consisting of (a) a 5-membered ring-containing compound, (b) a 6-membered ring-containing compound, (c) a fused ring-containing compound, (d) an alkyl ammonium salt, (e) a heterocycle-containing alkyl ammonium salt, and (f) a zwitterionic compound. The cleaning solution according to the present embodiment preferably contains one selected from such a group.

[0066] The (a) five-membered ring-containing compound is preferably a nitrogen-containing five-membered ring-containing compound. Specific examples of the five-membered ring-containing compound are preferably compounds having the following structures (compounds (a1) to (a8)).

[0067] [ka]

[0068] The (b) six-membered ring-containing compound is preferably a nitrogen-containing six-membered ring-containing compound. Specific examples of the six-membered ring-containing compound are preferably the compounds having the following structures (compounds (b1) to (b6)).

[0069] [ka]

[0070] The (c) fused ring-containing compound is preferably a nitrogen-containing fused ring-containing compound. Specific examples of the fused ring-containing compound are preferably compounds having the following structures (compounds (c1) to (c5)).

[0071] [ka]

[0072] As the (d) alkylammonium salt, compounds having the following structures (compounds (d1) to (d6)) are preferred. Note that the following alkylammonium salts are alkylammonium salts not containing a heterocycle.

[0073] [ka]

[0074] As the (e) heterocycle-containing alkylammonium salt, compounds having the following structures (compounds (e1) to (e3)) are preferred.

[0075] [ka]

[0076] (f) As the zwitterionic compound, compounds having the following structures (compounds (f1) to (f3)) are preferred.

[0077] [ka]

[0078] The anticorrosive agent may be a salt of the above-mentioned compound. Specific examples of the salt include, but are not limited to, sodium salt, potassium salt, ammonium salt, alkylammonium salt (e.g., tetramethylammonium salt, etc.), etc. The anticorrosive agent may also be a hydrate of the above-mentioned compound.

[0079] The concentration of the anticorrosive agent in the cleaning solution according to the present embodiment is preferably 0.0001 to 10% by mass. The upper limit of the concentration of the anticorrosive agent is more preferably 5% by mass or less, and even more preferably 1% by mass or less. The lower limit of the concentration of the anticorrosive agent is more preferably 0.001% by mass or more, and even more preferably 0.01% by mass or more.

[0080] (Buffer)

[0081] The cleaning solution according to the present embodiment may contain a buffering agent. The buffering agent is a compound that has the effect of suppressing changes in the pH of the cleaning solution. By containing a buffering agent, the pH value of the cleaning solution can be efficiently controlled to be smaller than the acid dissociation constant. In addition, by containing a buffering agent, the pH of the cleaning solution can be efficiently controlled to be a predetermined value. The buffering agent is not particularly limited as long as it is a compound having pH buffering ability.

[0082] Examples of the buffer include Good's buffers. Examples of the 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), tricine, 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) (PIPES), N-(2-acetamido)-2-aminoethanesulfonic acid (ACES), 2-hydroxy-3-morpholinopropanesulfonic acid (M OPSO), 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), and the like.

[0083] The buffering agent may be used alone or in combination of two or more kinds. Alternatively, the cleaning solution according to the present embodiment may not contain a buffering agent.

[0084] (Surfactant)

[0085] The cleaning solution according to this embodiment may contain a surfactant for the purpose of adjusting the wettability of the cleaning solution to the substrate, etc. Examples of the surfactant include a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant.

[0086] Examples of nonionic surfactants include polyalkylene oxide alkyl phenyl ether surfactants, polyalkylene oxide alkyl ether surfactants, block polymer surfactants consisting of polyethylene oxide and polypropylene oxide, polyoxyalkylene distyrene-type phenyl ether surfactants, polyalkylene tribenzyl phenyl ether surfactants, and acetylene polyalkylene oxide surfactants.

[0087] Examples of anionic surfactants include alkylsulfonic acid, alkylbenzenesulfonic acid, alkylnaphthalenesulfonic acid, alkyldiphenylethersulfonic acid, fatty acid amidesulfonic acid, polyoxyethylene alkylether carboxylic acid, polyoxyethylene alkylether acetic acid, polyoxyethylene alkylether propionic acid, alkylphosphonic acid, and fatty acid salts. These salts are not particularly limited, but include, for example, sodium salts, potassium salts, ammonium salts, and alkylammonium salts (e.g., tetramethylammonium salts).

[0088] Examples of cationic surfactants include alkylpyridinium surfactants and quaternary ammonium salt surfactants.

[0089] Examples of amphoteric surfactants include betaine type surfactants, amino acid type surfactants, imidazoline type surfactants, and amine oxide type surfactants.

[0090] These surfactants are generally commercially available. The surfactants may be used alone or in combination of two or more.

[0091] When the cleaning solution according to the present embodiment contains a surfactant, the content of the surfactant is not particularly limited, but is, for example, preferably 0.0001% by mass to 5% by mass relative to the total mass of the cleaning solution. The lower limit of the content is more preferably 0.0002% by mass or more, and even more preferably 0.002% by mass or more. The upper limit of the content is more preferably 3% by mass or less, even more preferably 1% by mass or less, and even more preferably 0.2% by mass or less.

[0092] The cleaning solution according to the present embodiment may not contain one or more selected from the group consisting of nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants, and may not contain one or more of the compounds exemplified above as these surfactants. The cleaning solution according to the present embodiment may not contain a surfactant.

[0093] (pH adjuster)

[0094] The cleaning solution according to the present embodiment may contain a pH adjuster to adjust the pH to a desired level. As the pH adjuster, an inorganic acid, an organic acid, an organic basic compound, or an inorganic basic compound can be appropriately used.

[0095] (Impurities, etc.)

[0096] The cleaning solution according to this embodiment may contain metal impurities including at least one type of metal atom selected from the group consisting of, for example, Fe atoms, Cr atoms, Ni atoms, Zn atoms, Ca atoms, and Pb atoms.

[0097] The total content of metal atoms in the cleaning solution according to the present embodiment is preferably 100 mass ppt or less with respect to the total mass of the cleaning solution. The lower limit of the total content of metal atoms is preferably as low as possible, and may be, for example, 0.001 mass ppt or more. The total content of metal atoms may be, for example, 0.001 mass ppt to 100 mass ppt. By making the total content of metal atoms equal to or less than the above-mentioned preferable upper limit, it is considered that the defect suppression and residue suppression properties of the cleaning solution are improved. By making the total content of metal atoms equal to or more than the above-mentioned preferable lower limit, it is considered that the metal atoms are less likely to be isolated and present in the system, and thus are less likely to adversely affect the manufacturing yield of the entire cleaning object.

[0098] The content of metal impurities can be adjusted, for example, by a purification treatment such as filtering, etc. The purification treatment such as filtering may be performed on a part or all of the raw material before preparing the cleaning liquid, or may be performed after preparing the cleaning liquid.

[0099] The cleaning solution according to the present embodiment may contain, for example, impurities derived from organic matter (organic impurities). The total content of the organic impurities in the cleaning solution according to the present embodiment is preferably 5000 mass ppm or less. The lower limit of the content of the organic impurities is preferably as low as possible, and may be, for example, 0.1 mass ppm or more. The total content of the organic impurities may be, for example, 0.1 mass ppm to 5000 mass ppm.

[0100] The cleaning solution according to this embodiment may contain countable objects of a size that can be counted by, for example, a light scattering type liquid particle counter. The size of the countable objects is, for example, 0.04 μm or more. The number of countable objects in the cleaning solution according to this embodiment is, for example, 1,000 or less per 1 mL of cleaning solution, with the lower limit being, for example, 1 or more. It is believed that by keeping the number of countable objects in the cleaning solution within the above-mentioned range, the metal corrosion suppression effect of the cleaning solution is improved.

[0101] The organic impurities and / or countable substances 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 inevitable mixing during the manufacturing process of the cleaning solution include organic impurities contained in raw materials (e.g., organic solvents) used in the manufacturing of the cleaning solution, and mixing from the external environment during the manufacturing process of the cleaning solution (e.g., contamination), but are not limited to the above.

[0102] When the objects to be counted are added to the cleaning solution, the abundance ratio may be adjusted for each specific size, taking into consideration the surface roughness of the object to be cleaned, etc.

[0103] (solvent)

[0104] The cleaning liquid according to the present embodiment may contain a solvent. For example, it is preferable that the cleaning liquid according to the present embodiment contains water as the solvent. The cleaning liquid according to the present embodiment can be suitably used as a water-based cleaning liquid.

[0105] The content of water in the cleaning solution according to the present embodiment is not particularly limited, but is preferably 1 to 99% by mass. The lower limit of the content is more preferably 25% by mass or more, even more preferably 35% by mass or more, even more preferably 45% by mass or more, even more preferably 50% by mass or more, even more preferably 55% by mass or more, even more preferably 60% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, from the viewpoint of being able to maintain high levels of residue removability and corrosion prevention while imparting water solubility as an aqueous cleaning solution. The upper limit of the content is more preferably 98% by mass or less, even more preferably 97% by mass or less, from the viewpoint of being able to maintain high levels of residue removability and corrosion prevention while imparting water solubility as an aqueous cleaning solution. By having the water content within the above-mentioned range, other components can be dissolved uniformly and stably.

[0106] The cleaning solution according to the present embodiment may contain an organic solvent. Specific examples of the organic solvent are not particularly limited, but are preferably at least one selected from the group consisting of alcohol-based solvents, glycol ester-based solvents, sulfoxide-based solvents, sulfone-based solvents, amide-based solvents, lactone-based solvents, imidazolidinone-based solvents, nitrile-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, pyrrolidone-based solvents, and urea-based solvents. Furthermore, the cleaning solution according to the present embodiment contains at least one selected from the group consisting of alcohol-based solvents, glycol ester-based solvents, sulfoxide-based solvents, sulfone-based solvents, amide-based solvents, lactone-based solvents, imidazolidinone-based solvents, nitrile-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, pyrrolidone-based solvents, and urea-based solvents, and more preferably does not contain any other solvents. In addition, when the cleaning solution according to the present embodiment contains an organic solvent, it is preferable to use a water-soluble organic solvent from the viewpoint of the water solubility of the cleaning solution.

[0107] Specific examples of alcohol-based solvents include aliphatic alcohols such as methanol, ethanol, denatured ethanol, isopropanol, n-propanol, n-butanol, and 3-methoxy-3-methyl-1-butanol; and glycols such as ethylene glycol (also known as 1,2-ethanediol, monoethylene glycol), diethylene glycol (also known as 2,2'-oxydiethanol, diethyl glycol), propylene glycol (also known as propane-1,2-diol), dipropylene glycol, glycerin, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, furfuryl alcohol, and hexylene glycol (also known as 2-methyl-2,4-pentanediol).

[0108] Specific examples of glycol ester-based solvents include ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monobutyl ether, ethylene glycol dibutyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, triethylene glycol monobutyl ether, triethylene glycol dibutyl ether, ethylene glycol monohexyl ether, ethylene glycol dihexyl ether, diethylene glycol monohexyl ether, diethylene glycol dihexyl ether, and ethylene glycol-phenyl ether; ethylene glycol ether acetates such as ethylene glycol monobutyl ether acetate and diethylene glycol monobutyl ether acetate; propylene glycol propylene-based glycol ethers such as polypropylene glycol monomethyl ether (PGME), propylene glycol dimethyl ether, dipropylene glycol monomethyl ether (DPM), dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol dimethyl ether, propylene glycol monoethyl ether, propylene glycol diethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol diethyl ether, propylene glycol monopropyl ether, propylene glycol dipropyl ether, dipropylene glycol monopropyl ether, dipropylene glycol dipropyl ether, propylene glycol monobutyl ether, propylene glycol dibutyl ether, dipropylene glycol monobutyl ether, dipropylene glycol dibutyl ether, tripropylene glycol monobutyl ether, tripropylene glycol dibutyl ether, and propylene glycol phenyl ether;Examples of the propylene glycol ether acetates include propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, and propylene glycol diacetate.

[0109] Specific examples of sulfoxide solvents include dimethyl sulfoxide (DMSO), diethyl sulfoxide, dipropyl sulfoxide, diphenyl sulfoxide, and thiophene.

[0110] Specific examples of sulfone-based solvents include dimethyl sulfone, diethyl sulfone, tetramethylene sulfone, dipropyl sulfone, sulfolane (also known as tetramethylene sulfone), 3-methyl sulfolane, 2,4-dimethyl sulfolane, 3,4-dimethyl sulfolane, diphenyl sulfolane, 3,4-diphenylmethyl sulfolane, sulfolene, 3-methyl sulfolene, and 3-ethyl sulfolene.

[0111] Specific examples of the amide solvent include dimethylformamide (DMF), diethylformamide (DEF), dimethylacetamide (DMAc), N-methylpyrrolidine (MPD), and hexamethylphosphoric triamide (HMPA).

[0112] Specific examples of lactone solvents include γ-butyllactone, α-methyl-γ-butyrolactone, β-propiolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, γ-laurolactone, and hexanolactone.

[0113] Specific examples of the imidazolidinone solvent include 2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, 1,3-dipropyl-2-imidazolidinone, and 1,3-diisopropyl-2-imidazolidinone.

[0114] Specific examples of the nitrile solvent include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0115] Specific examples of ketone solvents include acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), diisobutyl ketone, cyclohexanone, diacetone alcohol, 1-hexanone, 2-hexanone, 4-heptanone, 2-heptanone (methyl amyl ketone), 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetylacetone, acetonylacetone, phenylacetone, acetophenone, methyl naphthyl ketone, methylcyclohexanone, ionone, isophorone, propylene carbonate, diacetonyl alcohol, and acetyl carbinol.

[0116] Specific examples of the ether solvent include diisopropyl ether, 1,4-dioxane, methyl tert-butyl ether (MTBE), dimethyl ether, diethyl ether, dipropyl ether, and methyl phenyl ether.

[0117] Specific examples of ester-based solvents include methyl acetate, ethyl acetate, butyl acetate, amyl acetate, propyl acetate, isopropyl acetate, methyl lactate, ethyl methoxyacetate, ethyl ethoxyacetate, 2-methoxybutyl acetate (2-methoxybutyl acetate), 3-methoxybutyl acetate (3-methoxybutyl acetate), 4-methoxybutyl acetate (4-methoxybutyl acetate), 3-methoxy-3-methylbutyl acetate (3-methoxy-3-methylbutyl acetate), 3-ethyl-3-methoxybutyl acetate (3-ethyl-3-methoxybutyl acetate), 4-methyl-4-methoxypentyl acetate, and methyl formate. Examples of the esters include ethyl formate, propyl formate, butyl formate, ethyl lactate (EL), propyl lactate, butyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and propyl 3-methoxypropionate.

[0118] Specific examples of pyrrolidone-based solvents include N-methylpyrrolidone (NMP), 2-pyrrolidone, and N-vinyl-2-pyrrolidone.

[0119] Specific examples of urea-based solvents include 1,3-dimethylurea, 1,3-diethylurea, 1,3-dipropylurea, 1,3-diisopropylurea, tetramethylurea, tetraethylurea, tetrapropylurea, tetraisopropylurea, and N,N-dimethylpropyleneurea.

[0120] Among the above, the organic solvent is preferably a water-soluble organic solvent. Among the above specific examples, suitable examples of the water-soluble organic solvent include alcohols such as isopropanol, ethanol, ethylene glycol, propylene glycol, glycerin, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, furfuryl alcohol, and hexylene glycol (also known as 2-methyl-2,4-pentanediol); glycol ester solvents such as diethylene glycol monobutyl ether and propylene glycol monomethyl ether; dimethyl sulfoxide; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and propylene glycol dimethyl ether; morpholines such as N-methylmorpholine N-oxide; and the like. Among these, more preferably, hexylene glycol (also known as 2-methyl-2,4-pentanediol) and the like are included.

[0121] By using such a suitable solvent, it is possible to further improve the corrosion resistance of layers (e.g., the metal wiring layer 20, the etching stop layer 30, the interlayer insulating film 40, or other functional layers) that contain metal components such as cobalt, copper, tungsten, ruthenium, aluminum, molybdenum, etc. as their main components. In other words, when such a solvent is used, it is possible to further effectively reduce damage (amount of film loss) to layers that contain cobalt, etc., without impairing the removability of titanium-based residues.

[0122] The organic solvent may be used alone or in combination of two or more kinds.

[0123] In addition, the cleaning solution according to this embodiment is expected to achieve the desired effect without using a halogen-based solvent. That is, the cleaning solution according to this embodiment can be used as an environmentally friendly halogen-free cleaning solution. From this perspective, suitable examples of the cleaning solution according to this embodiment include those that do not substantially contain halogen atoms, and even those that do not contain any halogen atoms. In particular, when fluorine atoms such as fluorides are not substantially contained, it is expected that damage to materials using silicon compounds such as SiN, SiO2, ILD, and interlayer insulating films can be more effectively suppressed. Note that "substantially not contained" does not exclude cases where the component is inevitably mixed as an impurity. For example, the content of the component in the cleaning solution is preferably 1 mass % or less, more preferably 0.5 mass % or less, even more preferably 0.3 mass % or less, even more preferably 0.1 mass % or less, and even more preferably 0 mass %.

[0124] Although the cleaning solution according to the present embodiment is expected to provide sufficient effects even if it does not contain an organic solvent, it is expected to provide sufficient effects even if it contains an organic solvent. That is, the cleaning solution according to the present embodiment may contain an organic solvent. From such a viewpoint, the content of the organic solvent in the present embodiment can be 0 to 95% by mass. The lower limit of the content of the cleaning solution may be 0% by mass, or may be, for example, 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more depending on the components of the cleaning solution. The upper limit of the content of the cleaning solution may be, for example, 90% by mass or less, 80% by mass or less, or 70% by mass or less.

[0125] When the cleaning solution according to the present embodiment contains water and an organic solvent, the content of the organic solvent is preferably 0.05 to 50% by mass relative to the total amount of water and the amount of the organic solvent. The lower limit of this content may be, for example, 0.1% by mass or more. The upper limit of this content is more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 10% by mass or less. When water and an organic solvent are contained, the above content ratio can be used to make a water-soluble mixed solvent as a solvent, which is preferable in that it can impart high water solubility to the cleaning solution.

[0126] The cleaning solution according to the present embodiment may not contain an organic solvent, but sufficient effects can be obtained even if the organic solvent is used in combination with water. When the organic solvent and water are used in combination, the combination is preferably an alcohol and water, more preferably a glycol and water, and even more preferably a hexylene glycol and water, from the viewpoint of imparting water solubility as an aqueous cleaning solution.

[0127] The cleaning solution according to this embodiment can be used for various purposes, among which, from the viewpoint of effectively utilizing the effects and advantages of this embodiment, it is suitable for cleaning a semiconductor substrate on which a film containing titanium or a titanium-based alloy is formed. More specifically, a suitable example of this embodiment is a cleaning solution for a semiconductor substrate, which includes a substrate and a film formed on the substrate, and the film contains titanium or a titanium-based alloy.

[0128] Here, an example of a semiconductor substrate for which the cleaning solution according to this embodiment can be used will be described.

[0129] FIG. 1 is a cross-sectional view showing an example of an element (semiconductor substrate) to be cleaned after dry etching.

[0130] The semiconductor element 100 shown in FIG. 1 includes a substrate 10, a metal wiring layer 20, an etching stop layer 30, and an interlayer insulating film 40 stacked in this order, and a hard mask layer (HM layer) 50 formed on the interlayer insulating film 40 (substrate 10 / metal wiring layer 20 / etching stop layer 30 / interlayer insulating film 40 / HM layer 50).

[0131] This semiconductor element 100 is in a state after dry etching has been performed in a wiring process, that is, after dry etching of the interlayer insulating film 40 has been performed using the HM layer 50 on which a prototype of the wiring pattern has been formed by dry etching as a mask. Dry etching residues 60 are attached to the side surfaces of the HM layer 50 and the interlayer insulating film 40. Note that, although the case of etching by dry etching is described here as an example, when etching is performed by wet etching, for example, the resulting residues will be wet etching residues.

[0132] In the spaces between the interlayer insulating films 40 in the wiring pattern, the metal wiring layer 20 is exposed and dry etching residues 60 are also attached.

[0133] The substrate 10 may be made of a material such as silicon, amorphous silicon, or glass.

[0134] The metal wiring layer 20 is a wiring layer containing one of metals such as molybdenum (Mo), tungsten (W), ruthenium (Ru), copper (Cu), iron (Fe), gold (Au), silver (Ag), nickel (Ni), aluminum (Al), lead (Pb), zinc (Zn), tin (Sn), tantalum (Ta), magnesium (Mg), cobalt (Co), bismuth (Bi), cadmium (Cd), titanium (Ti), zirconium (Zr), antimony (Sb), manganese (Mn), beryllium (Be), chromium (Cr), germanium (Ge), vanadium (V), gallium (Ga), hafnium (Hf), indium (In), niobium (Nb), rhenium (Re), and thallium (Tl), as well as metal oxides, metal nitrides, metal chlorides, and metal fluorides thereof.

[0135] The metal wiring layer 20 is not limited to wiring, but broadly includes functional layers such as electrodes, insulating layers, low dielectric layers, and various conductor layers. It includes layers formed by using the above-mentioned various metals, as well as their metal oxides, metal nitrides, metal chlorides, and metal fluorides. For example, silicon-based materials include SiN, SiO2, low-k films (SiOC films, SiCOH films, etc.), ILDs, etc.

[0136] The material of the interlayer insulating film 40 is not particularly limited as long as it has insulating properties, and a suitable material can be selected in consideration of manufacturing conditions, etc. As the interlayer insulating film 40, for example, a layer containing a silicon-based material such as SiO2, SiN, SiOC, or SiOCN can be used.

[0137] The material of the HM layer 50 is not particularly limited as long as it functions as a protective film against etching, and a suitable material can be selected in consideration of the manufacturing conditions, etc. As the HM layer 50, for example, a layer containing titanium and a titanium-based alloy can be suitably used. The cleaning solution according to this embodiment is excellent in removing at least titanium-based residues, and therefore can efficiently remove residues (see dry etching residues 60) generated from an HM layer using such a material. As mentioned above, examples of titanium-based alloys include titanium nitride (TiN), titanium oxide (TiO x (x represents a number.) Titanium-based materials such as titanium oxynitride (TiON) and titanium oxyfluoride (TiOF) can be used.

[0138] The dry etching residue 60 is mainly a Ti-containing residue that contains a titanium-based material derived from the HM layer 50, but is not limited to such a residue. The dry etching residue 60 includes, for example, the above-mentioned etching residue containing an inorganic substance.

[0139] <Cleaning method>

[0140] The cleaning solution according to this embodiment can be suitably used as a method for cleaning a semiconductor substrate. The cleaning method according to this embodiment is a method for cleaning a semiconductor substrate having a protective film, and includes a step of removing impurities from the semiconductor substrate by contacting the protective film with the above-mentioned cleaning solution. For example, in the case of a semiconductor element 100 (semiconductor substrate) shown in FIG. 1, the protective film corresponds to the HM layer 50. Hereinafter, the cleaning of the semiconductor element 100 shown in FIG. 1 will be described as an example.

[0141] The cleaning method according to the present embodiment is a process of cleaning the semiconductor element 100 after dry etching in the wiring process, using the above-mentioned cleaning solution. The cleaning method is not particularly limited, and any known cleaning method can be used.

[0142] When the cleaning liquid is brought into contact with the semiconductor element 100 to be cleaned, the cleaning liquid may be diluted 2 to 2000 times to obtain a diluted liquid, and then the cleaning operation may be performed using this diluted liquid.

[0143] Examples of cleaning operations include a method in which a cleaning liquid is continuously applied onto a semiconductor element 100 rotating at a constant speed (spin coating method), a method in which the semiconductor element 100 is immersed in a cleaning liquid for a certain period of time (dip method), and a method in which a cleaning liquid is sprayed onto the surface of the semiconductor element 100 (spray method).

[0144] The temperature at which the cleaning process is carried out is not particularly limited, but is preferably carried out under conditions of 10 to 80°C. The lower limit of the cleaning process temperature (temperature of the cleaning solution) is more preferably 20°C or higher, and even more preferably 40°C or higher. The upper limit of the cleaning process temperature (temperature of the cleaning solution) is more preferably 75°C or lower, and even more preferably 70°C or lower. By setting the lower limit of the cleaning process temperature within the above-mentioned range, the removability of etching residues can be further improved. Furthermore, by setting the upper limit of the cleaning process temperature within the above-mentioned range, unintended composition changes in the cleaning solution can be more effectively suppressed, and cleaning can be more efficiently carried out in terms of workability, safety, cost, and the like.

[0145] The cleaning time can be appropriately selected so as to be sufficient to remove etching residues, impurities, and the like adhering to the surface of the semiconductor element 100. The cleaning time is preferably, for example, 10 seconds to 30 minutes. The lower limit of the cleaning time is more preferably 20 seconds or more, and even more preferably 30 seconds or more. The upper limit of the cleaning time is more preferably 15 minutes or less, even more preferably 10 minutes or less, and even more preferably 5 minutes or less.

[0146] Since cleaning is performed using the cleaning solution according to this embodiment, in the semiconductor element 100 with the dry etching residues 60 attached, the dry etching residues 60 originating from the HM layer 50, which is a protective film, can be effectively cleaned and removed while suppressing damage to the metal wiring layer 20. In particular, in the case of an HM layer containing titanium and / or a titanium alloy, the cleaning solution according to this embodiment is particularly suitable because of its excellent removability of titanium-based residues.

[0147] In addition, by using the cleaning solution according to this embodiment, damage to various functional layers (metal wiring layer 20, etching stop layer 30, interlayer insulating film 40, etc.) other than the protective film can also be suppressed.

[0148] Furthermore, the cleaning solution according to the present embodiment can provide a practical level of cleaning effect without using conventional general-purpose hydroxylamine or the like, and is therefore expected to have the advantage of enabling the manufacture of semiconductor devices and the like to be carried out more safely.

[0149] <Semiconductor manufacturing method>

[0150] The cleaning solution according to this embodiment and the cleaning method using the same can be suitably used as a method for manufacturing a semiconductor. The method for manufacturing a semiconductor according to this embodiment includes, for example, (1) a step of preparing a substrate having a protective film, (2) a step of etching the protective film, and (3) a step of removing impurities from the substrate by contacting the substrate with the above-mentioned cleaning solution after etching. As in the explanation of the cleaning method, the protective film corresponds to the HM layer 50 in the case of the semiconductor element 100 (semiconductor substrate) shown in FIG. 1, for example. Hereinafter, the cleaning of the semiconductor element 100 shown in FIG. 1 will be explained as an example.

[0151] (1) preparing a substrate having a protective film

[0152] In step (1), a substrate having at least a protective film is prepared. Although not shown, in the case of Fig. 1, a laminate (substrate 10 / metal wiring layer 20 / etching stop layer 30 / interlayer insulating film 40 / HM layer 50) having a substrate 10, a metal wiring layer 20, an etching stop layer 30, an interlayer insulating film 40, and a hard mask layer (HM layer) 50 equivalent to a protective film in this order is prepared before etching.

[0153] The method for sequentially stacking the substrate 10, the metal wiring layer 20, the etching stop layer 30, the interlayer insulating film 40, and the hard mask layer (HM layer) 50 corresponding to the protective film on the substrate 10 is not particularly limited, and any known method can be adopted.

[0154] (2) Etching the protective film

[0155] Subsequently, the protective film is etched. The etching method is not particularly limited, and may be wet etching or dry etching, but is preferably dry etching. Dry etching is advantageous in that metal wiring at the nano level is possible and the gas used can be controlled. In addition, dry etching is advantageous in that damage to the substrate and the like is relatively large, but it is desirable in that the advantage of this embodiment can be more effectively reflected from the viewpoint that such damage can be effectively suppressed by using the cleaning solution according to this embodiment.

[0156] In the case of dry etching, plasma can be used. Usually, when performing plasma etching, there are problems such as the substrate being easily damaged and the plasma etching residue being generated, which must be cleaned with a cleaning solution. However, the use of the cleaning solution according to the present embodiment is preferable in that such problems can be effectively suppressed.

[0157] (3) After etching, the step of removing impurities from the substrate by contacting the substrate with the above cleaning solution. The above-mentioned cleaning method can be used as the step (3), thereby obtaining the semiconductor device 100. Furthermore, if necessary, known post-treatment can be performed after cleaning.

[0158] As described above, the cleaning solution according to this embodiment can be used as a cleaning solution for removing residues generated in, for example, a semiconductor etching process, and is particularly suitable for removing residues generated by dry etching. The cleaning solution according to this embodiment has the advantages of being able to efficiently remove titanium-based residues and having excellent corrosion resistance. Therefore, the residues generated during dry etching of a substrate having a hard mask layer (HM layer) mainly composed of titanium or a titanium-based alloy can be removed more efficiently than in the past.

[0159] In addition, problems such as large damage to the film (i.e., large film loss) may occur when using cleaning solutions containing hydroxylamine, hydrogen fluoride, and hydrogen peroxide, which have been used in the past. However, the cleaning solution according to the present embodiment has excellent anticorrosive properties, and can effectively suppress the occurrence of such problems. For example, it is preferable because it is expected to reduce damage to substrates, metal wiring, etching stop layers, interlayer insulating films, and various other functional layers containing silicon compounds such as Si and SiN, and metal components such as tungsten, molybdenum, and cobalt. Therefore, it is fully possible to make a cleaning solution that is particularly excellent in the removability of titanium-based residues and the anticorrosive properties of highly versatile materials such as silicon compounds and metal materials such as tungsten, molybdenum, and cobalt.

[0160] Furthermore, the cleaning solution according to the present embodiment can be made halogen-free, so it is not only environmentally friendly but also easy to use in terms of waste liquid treatment. In particular, when no fluoride is used, it is expected that damage to materials using silicon compounds such as Si and SiN can be more effectively suppressed. EXAMPLES

[0161] The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to the following examples in any way.

[0162] 1. Test 1

[0163] 1-1. Preparation of cleaning solution

[0164] <Example 1> Cleaning solutions were obtained by mixing oxalic acid ((COOH)2) and water in the ratios shown in Table 2. Example 1 is a cleaning solution containing only 3 mass % oxalic acid and 97 mass % water as cleaning agents.

[0165] <Examples 2 and 3, Comparative Examples 1 to 3> A cleaning solution was obtained in the same manner as in Example 1, except that the cleaning agent and water were mixed in the ratio shown in Table 2. For example, Example 2 is a cleaning solution containing 10% by mass of phosphoric acid and 90% by mass of water.

[0166] <pKa of oxoacid> The pKa of the oxoacid contained in the cleaning solution (for example, oxalic acid in the case of Example 1) was calculated using the "Sparc Calculator" (archemcalc.com) operated on the Internet by Archem. (Reference URL: http: / / archemcalc.com / sparc-web / calc# / multiproperty) The request was made based on the above.

[0167] <How to measure the pH of the cleaning solution> The pH of the cleaning solution was measured at a temperature of 22° C. using a pH / ORP meter (portable pH meter "ORION STAR A324", manufactured by Thermo Scientific).

[0168] 1-2. Evaluation of titanium-based residue removability (residue removability)

[0169] The residue removability of each Example and Comparative Example was evaluated by the following method.

[0170] First, a laminate (substrate having a film) was prepared by laminating a third layer (metal wiring layer, cobalt), an etching stop layer (aluminum oxide), a second layer (interlayer insulating film), and a first layer (metal hard mask layer, titanium oxide: film thickness 50 nm) in this order on a substrate (12-inch silicon substrate) using a CVD method in cross-sectional view (substrate / third layer / etching stop layer / second layer / first layer). A test sample was prepared by cutting this laminate into a size of 2 cm x 2 cm in top view.

[0171] Next, the obtained sample (laminate) was subjected to plasma etching using the first layer as a mask, and the second layer was etched until the surface of the third layer was exposed, forming a hole (diameter / shape: 40 nm / hole-shaped) to prepare a measurement substrate (sample after etching) having the configuration shown in Figure 1 (see Figure 1).

[0172] Then, the sample (measurement substrate) after etching was washed. The washing was performed by the following method. First, the treatment liquid of each Example and Comparative Example was heated to 58°C. Then, the sample after etching was immersed in the treatment liquid of each Example and Comparative Example at 58°C for 5 minutes. Then, the sample was pulled out of the treatment liquid, washed with isopropyl alcohol, and dried by nitrogen blowing. Then, the remaining state of the residue of this sample was confirmed by a scanning electron microscope (SEM, imaging magnification: 100k times, equipment name "SU-8220", manufactured by Hitachi High-Technologies Corporation). Specifically, the residue removability was evaluated by confirming whether or not etching residue (titanium-based residue) was present on the wall surface of the hole. The evaluation of the residue removability was performed based on the following criteria. Note that no corrosion to a degree that would be a practical problem was confirmed in any of the metal layers of the measurement substrates of each Example.

[0173] The criteria for judging the residue removability are as follows.

[0174] A: Residues observed by SEM before immersion were confirmed to have been removed by 95% or more after immersion under the same conditions. B: The residue confirmed by SEM before immersion was confirmed by SEM after immersion under the same conditions, and 85% or more but less than 95% of the residue was removed. C: The residue confirmed by SEM before immersion was confirmed by SEM after immersion under the same conditions, and 80% or more but less than 85% of it was removed. D: The residue observed by SEM before immersion was examined by SEM after immersion under the same conditions, and it was found that less than 80% of the residue had been removed.

[0175] 1-3.Evaluation of corrosion prevention (film loss)

[0176] The corrosion resistance of each of the Examples and Comparative Examples was evaluated by the following method.

[0177] First, laminates (substrates having films) each including a metal layer were prepared as described below. A laminate was prepared by depositing a metal layer of SiN (20 nm thick) on a substrate (12-inch silicon substrate) using the CVD method. A laminate was prepared by depositing a W metal layer (thickness: 100 nm) on a substrate (12-inch silicon substrate) using the CVD method. A laminate was prepared by depositing a Mo metal layer (40 nm thick) on a substrate (12-inch silicon substrate) using the PVD method.

[0178] Next, each of the obtained laminates (substrates having a film) was cut to 2 cm x 2 cm in top view to obtain a test sample (wafer coupon). Then, 80 mL of the cleaning solution of each of the examples and comparative examples was placed in a 100 mL cup. The sample was placed therein and immersed in the cleaning solution at the temperature and treatment time described in the table. For example, in the case of SiN in Table 2, the sample was immersed at 58°C for 30 minutes. During the immersion, the cleaning solution was stirred at 300 rpm. After immersion, the sample was taken out of the cleaning solution, washed with water at room temperature for 30 seconds, and dried with nitrogen blow.

[0179] The film thickness of the sample was measured before and after immersion in the cleaning solution. The film loss (see "film loss" in the table) was calculated by calculating the difference between the two values ​​as the change in film thickness. For example, the film loss of the SiN film in Example 1 was 3.4 Å ("Å" = unit: angstrom, see Table 2).

[0180] The film thickness was measured by the following method. The thickness of the SiN film was measured using an ellipsometer ("L115S300 STOKES WAFERSKAN", manufactured by Gaertner Scientific Corporation). The unit of film thickness is angstroms unless otherwise specified. Other film thicknesses were measured using a scanning X-ray fluorescence analyzer ("ZSX PrimusIV", Rigaku Corporation).

[0181] The SiN film loss was evaluated based on the following criteria. A: Less than 10 Å. B: 10 Å or more and less than 50 Å. C: 50 Å or more.

[0182] The amount of W film loss ("W film loss") was evaluated based on the following criteria. A: Less than 15 Å. B: 15 Å or more and less than 50 Å. C: 50 Å or more and less than 100 Å. D: 100 Å or more.

[0183] The Mo film loss was evaluated based on the following criteria. A: Less than 20 Å. B: 20 ​​Å or more and less than 30 Å. C: 30 Å or more and less than 100 Å. D: 100 Å or more.

[0184] Table 2 shows the compositions of the cleaning solutions and the evaluation results of each of the examples and comparative examples.

[0185] [Table 2]

[0186] (COOH)2: oxalic acid, H3PO4: phosphoric acid, H2SO4: sulfuric acid, HF: Hydrogen fluoride, H2O2: Hydrogen peroxide, HA: Hydroxylamine

[0187] 2. Test 2

[0188] 2-1. Preparation of cleaning solution

[0189] <Example 4> A cleaning solution was obtained by mixing oxalic acid ((COOH)2) and water in the ratio shown in Table 3. Example 4 is a cleaning solution containing only 3 mass % oxalic acid and 97 mass % water as the cleaning agent.

[0190] <Examples 5 and 6, Comparative Examples 4 to 9> A cleaning solution was obtained in the same manner as in Example 4, except that the cleaning agent and water were mixed in the ratios shown in Tables 3 and 4. For example, Example 5 is a cleaning solution containing 3 mass % phosphoric acid and 97 mass % water.

[0191] <pKa of oxoacid> The pKa of the oxoacid (for example, phosphoric acid in the case of Example 5) was determined by a method similar to that in "1. Test 1" above.

[0192] <How to measure the pH of the cleaning solution> The pH of the cleaning solution was measured in the same manner as in "1. Test 1" above.

[0193] <Oxidation-reduction potential (ORP) of cleaning solution> The ORP of the cleaning solution was measured at a temperature of 22°C using a pH / ORP meter (portable pH meter "ORION STAR A324", manufactured by Thermo Scientific).

[0194] 2-2. Evaluation of titanium-based residue removability (residue removability)

[0195] Test samples were prepared in the same manner as in "1. Test 1" "1-2. Evaluation of removability of titanium-based residue (residue removability)" above, and the removability of titanium-based residue was evaluated.

[0196] 2-3.Evaluation of corrosion prevention (film loss)

[0197] Test samples were prepared and the corrosion resistance was evaluated in the same manner as in "1. Test 1" "1-3. Evaluation of corrosion resistance (amount of film loss)" above.

[0198] Tables 3 and 4 show the compositions of the cleaning solutions and the evaluation results of each of the Examples and Comparative Examples.

[0199] [Table 3]

[0200] [Table 4]

[0201] HA: hydroxylamine, B(OH)3: boric acid, HCOOH: formic acid, CH3COOH: acetic acid, HNO3: nitric acid, MSA: methanesulfonic acid, HCl: hydrochloric acid. Since hydroxylamine (HA) is not an acid, the "valence" in the table is recorded as "0". In addition, in Comparative Examples 5 to 9, the residue removability was "x", so the film thickness could not be measured accurately. Therefore, in Comparative Examples 5 to 9, the film loss could not be calculated. Therefore, the film loss in Comparative Examples 5 to 9 is recorded as "ND" in the table.

[0202] 3. Test 3

[0203] 3-1. Preparation of cleaning solution

[0204] <Examples 7 and 8> A cleaning solution was obtained by mixing oxalic acid ((COOH)2), 5-aminotetrazole, and water in the ratios shown in Table 5. For example, Example 8 is a cleaning solution containing 3 mass % oxalic acid, 1 mass % 5-aminotetrazole, and 96 mass % water as cleaning agents.

[0205] <pKa of oxoacid> The pKa of an oxoacid (for example, oxalic acid in the cases of Examples 7 and 8) was determined by a method similar to that in "1. Test 1" above.

[0206] <How to measure the pH of the cleaning solution> The pH of the cleaning solution was measured in the same manner as in "1. Test 1" above.

[0207] 3-2. Evaluation of titanium residue removability (etching residue removability)

[0208] Test samples were prepared in the same manner as in "1. Test 1", "1-2. Evaluation of removability of titanium-based residue" above, and the removability of titanium-based residue was evaluated.

[0209] 3-3.Evaluation of corrosion prevention (film loss)

[0210] The corrosion resistance of each of the Examples and Comparative Examples was evaluated by the following method.

[0211] First, laminates (substrates having films) each including a metal layer were prepared as described below. A laminate was prepared by depositing a metal layer of SiN (20 nm thick) on a substrate (12-inch silicon substrate) using the CVD method. A laminate was prepared by depositing a W metal layer (thickness: 100 nm) on a substrate (12-inch silicon substrate) using the CVD method. A laminate was prepared by depositing a Mo metal layer (40 nm thick) on a substrate (12-inch silicon substrate) using the PVD method. A laminate was prepared by depositing a Co metal layer (20 nm thick) on a substrate (12-inch silicon substrate) using the CVD method.

[0212] Next, each of the obtained laminates (substrates having a film) was cut to 2 cm x 2 cm in top view to obtain a test sample (wafer coupon). Then, 80 mL of the cleaning solution of each of the Examples and Comparative Examples was placed in a 100 mL cup. The sample was placed therein and immersed in the cleaning solution at the temperature and treatment time described in the table. During immersion, the cleaning solution was stirred at 300 rpm. For example, in the case of SiN in Table 5, the sample was immersed at 58°C for 30 minutes. After immersion, the sample was taken out of the cleaning solution, washed with water at room temperature for 30 seconds, and dried with nitrogen blow.

[0213] Then, a test sample was prepared in the same manner as in "1. Test 1" "1-3. Evaluation of corrosion prevention (amount of film loss)" above, and the corrosion prevention was evaluated. However, the corrosion prevention properties of Co (amount of film loss) were evaluated as a relative ratio with the reference value being "100." The amount of film loss of Co in Example 8 was expressed as a relative ratio with the value of the amount of film loss in Example 7, which did not contain a corrosion inhibitor, set at 100. For example, the amount of film loss in Example 8 in the table indicates that it is 30 / 100 of the amount of film loss in Example 7.

[0214] Table 5 shows the composition of the cleaning solution and the evaluation results of each example.

[0215] [Table 5]

[0216] 4. Test 4

[0217] 4-1. Preparation of cleaning solution

[0218] <Examples 9 to 11> Cleaning solutions were prepared with the compositions shown in Table 6. For example, Example 9 is a cleaning solution containing 3 mass% oxalic acid as an oxoacid, 0 mass% organic solvent, and 97 mass% water. Example 10 is a cleaning solution containing 3 mass% oxalic acid as an oxoacid, 40 mass% hexylene glycol (HG) as an organic solvent, and 57 mass% water.

[0219] <pKa of oxoacid> The pKa of an oxoacid (for example, oxalic acid in the cases of Examples 9 to 11) was determined by a method similar to that in "1. Test 1" above.

[0220] <How to measure the pH of the cleaning solution> The pH of the cleaning solution was measured in the same manner as in "1. Test 1" above.

[0221] 4-2. Evaluation of titanium-based residue removability (residue removability)

[0222] Test samples were prepared in the same manner as in "3. Test 3", "3-2. Evaluation of removability of titanium-based residue" above, and the removability of titanium-based residue was evaluated.

[0223] 4-3.Evaluation of corrosion prevention (film loss)

[0224] Test samples were prepared and the corrosion resistance was evaluated in the same manner as in "3. Test 3" "3-3. Evaluation of corrosion resistance (amount of film loss)" above. However, the corrosion prevention properties of Co (amount of film loss) were evaluated as a relative ratio with the reference value set to "100." The film loss amounts of Examples 10 and 11 were expressed as relative ratios with the film loss amount of Example 9, which did not contain a corrosion inhibitor, set to 100. For example, the film loss amount of Example 10 in the table indicates that it is 69 / 100 of the film loss amount of Example 7.

[0225] Table 6 shows the composition of the cleaning solution and the evaluation results of each example.

[0226] [Table 6]

[0227] From the above, it was at least confirmed that the cleaning solution according to the present embodiment can efficiently remove titanium-based residues and has excellent corrosion prevention properties. Such a cleaning solution can be suitably used in a method for cleaning a semiconductor substrate and a method for manufacturing a semiconductor.

[0228] This application claims priority to U.S. Provisional Application No. 63 / 509930, filed with the U.S. Patent and Trademark Office on June 23, 2023, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0229] 10: Substrate 20: Metal wiring layer 30: Etch stop layer 40: Interlayer insulating film 50: Hard mask layer 60: Etching residue 100: Semiconductor element (semiconductor substrate)

Claims

1. The acid dissociation constant pKa is less than 5.0 and contains a divalent or higher oxyacid; A cleaning solution having a pH value less than said acid dissociation constant.

2. 2. The cleaning solution according to claim 1, having a pH of 5.0 or less.

3. The oxoacids include oxalic acid, malonic acid, H ３ P.O. ４ 2. The cleaning solution according to claim 1, which is at least one selected from the group consisting of sulfuric acid.

4. 2. The cleaning solution according to claim 1, wherein the concentration of the oxoacid is 0.005 to 20% by mass.

5. 2. The cleaning solution according to claim 1, further comprising, as a corrosion inhibitor, at least one selected from the group consisting of a nitrogen-containing heterocycle-containing compound, a mercapto group-containing compound, an aliphatic amine compound, a zwitterionic compound, and a salt thereof.

6. The cleaning solution according to claim 1 , further comprising water as a solvent.

7. 2. The cleaning solution according to claim 1, further comprising at least one solvent selected from the group consisting of alcohol-based solvents, glycol ester-based solvents, sulfoxide-based solvents, sulfone-based solvents, amide-based solvents, lactone-based solvents, imidazolidinone-based solvents, nitrile-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, pyrrolidone-based solvents, and urea-based solvents.

8. 10. The cleaning solution of claim 1, which is free of hydrogen peroxide, hydrogen fluoride, and hydroxylamine.

9. The cleaning liquid is a cleaning liquid for semiconductor substrates, The semiconductor substrate includes a substrate and a film formed on the substrate, The film contains titanium or a titanium-based alloy. The cleaning solution according to claim 1.

10. A method for cleaning a semiconductor substrate having a protective film, comprising the steps of:

13. A method for cleaning a semiconductor substrate, comprising the step of removing impurities from the semiconductor substrate by contacting the protective film with the cleaning solution according to claim 1.

11. Providing a substrate having a protective film; Etching the protective film; removing impurities from the substrate by contacting the substrate with the cleaning solution according to claim 1 after the etching; A method for manufacturing a semiconductor, comprising:

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