Cleaning solution, method for cleaning a substrate, and method for manufacturing a semiconductor device.

Abstract

To provide a cleaning solution with good removal of dry etching residue and damage reduction to metal wiring, as well as enhanced safety, and a method for cleaning the substrate and a method for manufacturing a semiconductor element using the cleaning solution.SOLUTION: The present invention employs a cleaning solution for removing etching residue containing inorganic material, which contains a compound (A) represented by general formula (a1) and at least one base selected from the group consisting of amine and ammonium compounds other than compound (A). In general formula (a1), -R is -NH2 or -O-C(CH3)3.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a cleaning liquid, a method for cleaning a substrate, and a method for manufacturing a semiconductor device.

Background Art

[0002] In a 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 a silicon-based interlayer insulating film are laminated in this order, and the HM layer is etched to form a prototype of a wiring pattern. The HM layer contains titanium nitride (TiN) or titanium oxide (TiOx). Next, the interlayer insulating film is dry-etched using the etched HM layer as a mask to create a wiring pattern similar to the mask. Next, the HM layer is removed, and, for example, a copper metal film is embedded in the interlayer insulating film having the wiring pattern shape by electrolytic plating. In the device (substrate / metal wiring layer / interlayer insulating film / HM layer) after dry etching, inorganic matter-containing residues derived from the metal wiring layer and Ti-containing residues derived from the HM layer are attached.

[0003] Conventionally, dry etching residues have been removed by a cleaning process. As a cleaning liquid for removing dry etching residues, a cleaning liquid containing a peroxide as a residue remover has been proposed (see, for example, Patent Document 1). Alternatively, a cleaning liquid containing hydroxylamine as a residue remover has been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Ti-containing residue derived from the HM layer adhering to the element after dry etching is highly wet-resistant and difficult to remove by cleaning. However, when using the cleaning solution described in Patent Document 1, although it is effective against Ti-containing residue, it has the drawback that it damages molybdenum or tungsten wiring in substrates equipped with these wirings during the cleaning process. Furthermore, in cleaning solutions containing hydroxylamine, alternatives to residue removers are desirable due to concerns about the safety of hydroxylamine.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a cleaning solution that is safer and has good performance in removing dry etching residue and reducing damage to metal wiring, as well as a method for cleaning a substrate and a method for manufacturing a semiconductor device using this cleaning solution. [Means for solving the problem]

[0007] To solve the above problems, the present invention employs the following configuration.

[0008] A first aspect of the present invention is a cleaning solution for removing etching residue containing inorganic substances, comprising a compound (A) represented by the following general formula (a1), and at least one base selected from the group consisting of amines and ammonium compounds other than compound (A).

[0009] [ka] [In the formula, -R is either -NH2 or -OC(CH3)3.]

[0010] A second aspect of the present invention is a method for cleaning a substrate, comprising the step (P1) of cleaning a substrate with etching residue containing inorganic matter using a cleaning solution according to the first aspect.

[0011] A third aspect of the present invention is a method for manufacturing a semiconductor device, comprising the step (P1) of cleaning a substrate with etching residue containing inorganic matter using a cleaning solution according to the first aspect. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a cleaning solution that exhibits good performance in removing dry etching residue and reducing damage to metal wiring, thereby enhancing safety, as well as a method for cleaning a substrate and a method for manufacturing a semiconductor device using this cleaning solution. [Brief explanation of the drawing]

[0013] [Figure 1] This is a cross-sectional view showing an example of a device after dry etching that is to be cleaned. [Modes for carrying out the invention]

[0014] (First aspect: Cleaning solution) A cleaning solution according to a first aspect of the present invention is a cleaning solution for removing etching residue containing inorganic substances. As used herein, the "inorganic substance" refers to a compound containing metal atoms, and examples thereof include metal atoms, metal oxides, metal nitrides, metal chlorides, metal fluorides, etc. Examples of metal atoms include Ti, Ta, Cu, Co, Ru, Al, W, Mo, Au, Ag, Fe, Ni, Si, etc. Examples of metal oxides include TiOx, TaOx, CuOx, CoOx, RuOx, AlOx, WOx, MoOx, AuOx, AgOx, FeOx, NiOx, SiOx, etc. Examples of metal nitrides include TiNx, TaNx, CuNx, CoNx, RuNx, AlNx, WNx, MoNx, AuNx, AgNx, FeNx, NiNx, SiNx, etc. Examples of metal chlorides include TiClx, TaClx, CuClx, CoClx, RuClx, AlClx, WClx, MoClx, AuClx, AgClx, FeClx, NiClx, SiClx, etc. Examples of metal fluorides include TiFx, TaFx, CuFx, CoFx, RuFx, AlFx, WFx, MoFx, AuFx, AgFx, FeFx, NiFx, SiFx, etc. The etching residues include, particularly dry etching residues, such as Ti-containing residues derived from the HM layer adhered in the wiring process and inorganic substance-containing residues derived from the metal wiring layer. Since dry etching residues deteriorate the yield and electrical characteristics of the semiconductor, they need to be removed before the next process. The cleaning liquid according to this embodiment is suitable for cleaning the substrate after dry etching is performed by the wiring process.

[0015] One embodiment of the cleaning liquid according to this embodiment contains a compound (A) represented by the following general formula (a1) and at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A).

[0016] [Chemical formula] [In the formula, -R is -NH2 or -O-C(CH3)3.]

[0017] <Compound (A)> The cleaning liquid of this embodiment contains a compound (A) represented by the general formula (a1) (hereinafter also referred to as "(A) component"). In the cleaning liquid, the (A) component is used as a residue remover. The (A) component is safer than hydroxylamine. Also, the (A) component does not damage the metal wiring during the cleaning process. In the formula (a1), when -R is -NH2, the (A) component is hydroxyurea. In the formula (a1), when -R is -O-C(CH3)3, the (A) component is N-(tert-butoxycarbonyl)hydroxylamine.

[0018] In the cleaning liquid of this embodiment, the (A) component may be used alone, or two kinds may be used in combination. The content of the (A) component in the cleaning liquid of this embodiment is not particularly limited, but it is preferably 0.02% by mass or more and 20% by mass or less, more preferably 0.2% by mass or more and 18% by mass or less, and even more preferably 0.3% by mass or more and 15% by mass or less, based on the total mass of the cleaning liquid. When the content of the (A) component is at least the lower limit value of the above preferred range, the removability of the dry etching residue is further enhanced in the cleaning process. On the other hand, when the content of the (A) component is at most the upper limit value of the above preferred range, the damage to the metal wiring is more suppressed.

[0019] <Base> The cleaning liquid of this embodiment contains at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A). By containing this base, the pH of the cleaning liquid can be increased, and the residue removal effect of the (A) component is likely to be exhibited.

[0020] Examples of the amine other than the compound (A) in the base include ammonia (NH3), primary monoamine, secondary monoamine, tertiary monoamine, alkanolamine, secondary cyclic amine, tertiary cyclic amine, quaternary cyclic amine, diamine, and polyamine.

[0021] Examples of primary monoamines include alkylamines such as methylamine, ethylamine, propylamine, n-butylamine, isopropylamine, and tert-butylamine; cycloalkylamines such as cyclopentylamine, cyclohexylamine, and cyclohexanemethylamine; and alkoxyamines such as methoxyethylamine, methoxypropylamine, methoxybutylamine, ethoxypropylamine, and propoxypropylamine.

[0022] Examples of secondary monoamines include alkylamines such as dimethylamine, diethylamine, methylethylamine, dipropylamine, diisopropylamine, dibutylamine, diisobutylamine, and butylmethylamine; cycloalkylamines such as N,N-dicyclohexylamine and N-cyclopentylcyclohexaneamine; and alkoxyamines such as methoxy(methylamine) and N-(2-methoxyethyl)ethylamine.

[0023] Examples of tertiary monoamines include alkylamines such as trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, dimethylethylamine, dimethylpropylamine, allyldiethylamine, dimethyl-n-butylamine, and diethylisopropylamine; and cycloalkylamines such as tricyclopentylamine and tricyclohexylamine.

[0024] Examples of alkanolamines include monoethanolamine, diethanolamine, and triethanolamine.

[0025] Examples of secondary cyclic amines include piperidines (compounds having a piperidine skeleton), pyrrolidines (compounds having a pyrrolidine skeleton), and morpholines (compounds having a morpholine skeleton). Examples of piperidines, which are secondary cyclic amines, include piperidine, 2-pipecolin, 3-pipecolin, 4-pipecolin, 2,6-dimethylpiperidine, and 3,5-dimethylpiperidine. Examples of pyrrolidines include pyrrolidine, 2-methylpyrrolidine, and 3-methylpyrrolidine. Examples of morpholines include morpholine, 2-methylmorpholine, and 3-methylmorpholine.

[0026] Examples of tertiary cyclic amines include piperidines, pyrrolidines, and morpholines. Examples of piperidines include N-methylpiperidine. Examples of pyrrolidines include N-methylpyrrolidine. Examples of morpholines include N-methylmorpholine.

[0027] Examples of quaternary cyclic amines include fluorides, chlorides, bromides, iodides, sulfates, bisulfates, and acetates of piperidines, pyrrolidines, and morpholines.

[0028] The diamine may be a primary, secondary, or tertiary diamine. Examples of primary diamines include 2-(2-aminoethylamino)ethanol, ethylenediamine, butane-1,4-diamine, 1,3-propanediamine, 1,6-hexanediamine, and pentane-1,5-diamine. Examples of secondary diamines include 2-methylpiperazine, 2,3-dimethylpiperazine, 2,5-dimethylpiperazine, N,N'-dimethylethanediamine, N,N'-dimethylpropanediamine, N,N'-diethylethylenediamine, N,N'-diethylpropanediamine, and N,N'-diisopropylethylenediamine. Examples of tertiary diamines include 4-dimethylaminopyridine, 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, N,N,N',N'-tetramethylphenylenediamine, and 1,2-dipiperidinoethane.

[0029] Polyamines are compounds containing three or more amino groups, with triamines being preferred. Polyamines may contain primary, secondary, or 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, tris[2-(dimethylamino)ethyl]amine, 2-aminomethylpyrimidine, 1,4-bis(3-aminopropyl)piperazine, 1-amino-4-cyclopentylpiperazine, and 1-(2-pyridyl)piperazine.

[0030] Examples of ammonium compounds in bases include hydroxides of quaternary amines and quaternary ammonium salts other than hydroxides.

[0031] Examples of quaternary amine hydroxides include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, dimethylbis(2-hydroxyethyl)ammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, choline, dimethyldiethylammonium hydroxide, tetraethanolammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, and benzyltributylammonium hydroxide.

[0032] Quaternary ammonium salts other than hydroxides include quaternary ammonium fluorides, chlorides, bromides, iodides, sulfates, bisulfates, and acetates. Specific examples of quaternary ammonium salts include tetraethylammonium chloride, tetramethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetrapentylammonium chloride, tetraethylammonium bromide, tetramethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetrapentylammonium bromide, tetraethylammonium fluoride, tetramethylammonium fluoride, tetrapropylammonium fluoride, tetrabutylammonium fluoride, tetrapentylammonium fluoride, tetraethylammonium iodide, tetramethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetrapentylammonium iodide, tetraethylammonium bisulfate, tetramethylammonium bisulfate, tetrapropylammonium bisulfate, and tetrabutylammonium bisulfate.

[0033] In the washing solution of this embodiment, one type of base may be used alone, or two or more types may be used in combination. Among the bases, it is preferable to use at least one selected from the group consisting of ammonia, quaternary amine hydroxides, alkanolamines, and triamines, and it is more preferable to use at least one selected from the group consisting of ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, alkanolamines, and triamines. From the viewpoint of the ease of removing dry etching residue, it is preferable to use at least one selected from the group consisting of ammonia and triamine as the base, and ammonia is particularly preferred.

[0034] The base content in the cleaning solution of this embodiment is not particularly limited, but is preferably 0.003% to 15% by mass, more preferably 0.03% to 13% by mass, even more preferably 0.2% to 12% by mass, and particularly preferably 0.5% to 10% by mass, relative to the total mass of the cleaning solution. If the base content is above the lower limit of the preferred range mentioned above, the removal of dry etching residue during the washing process is further enhanced. On the other hand, if the base content is below the upper limit of the preferred range mentioned above, the combined effect with component (A) is more easily obtained.

[0035] In the cleaning solution of this embodiment, the base content is preferably 15 to 5000 parts by mass, more preferably 20 to 2500 parts by mass, and even more preferably 50 to 1000 parts by mass, per 100 parts by mass of compound (A). If the base content per 100 parts by mass of compound (A) is above the lower limit of the preferred range described above, the ability to remove dry etching residue and reduce damage to metal wiring during the cleaning process is more easily improved. On the other hand, if the base content is below the upper limit of the preferred range described above, the combined effect with component (A) is more easily obtained.

[0036] <Solvent> The cleaning solution of this embodiment preferably contains water as a solvent. The water may contain trace components that are inevitably mixed in. The water that may be used in the cleaning solution of this embodiment is preferably purified water such as distilled water, ion-exchanged water, and ultrapure water, and it is more preferable to use ultrapure water which is commonly used in semiconductor manufacturing. In the cleaning solution of this embodiment, water can be added in such a way that the total content of component (A), component (B), and any optional components described later, which may be added as needed, amounts to 100% by mass; in other words, the water content can be the residue. The cleaning solution of this embodiment may contain, in addition to water, an organic solvent as described later.

[0037] <Optional ingredients> The cleaning solution of this embodiment may contain optional components in addition to components (A) and (B) described above. Examples of optional components include corrosion inhibitors, buffering agents, organic solvents, surfactants, pH adjusters, and the like.

[0038] <<Corrosion Inhibitor>> The cleaning solution of this embodiment may contain a corrosion inhibitor. Examples of corrosion inhibitors include compounds containing nitrogen-containing heterocycles such as triazole rings, imidazole rings, pyridine rings, phenanthroline rings, tetrazole rings, pyrazole rings, pyrimidine rings, and purine rings.

[0039] ≪Cushioning material≫ The cleaning solution of this 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. The buffering agent is not particularly limited as long as it is a compound that has pH buffering capacity. For example, a compound with a pKa of 6 to 11 can be used as the buffering agent. Examples of buffering agents include Good's buffers. Good's buffers 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-acetamide)iminodiacetic acid (ADA), piperazine-1,4-bis(2-ethanesulfonic acid) (PIPES), N-(2-acetamide)-2-aminoethanesulfonic acid (ACES), and 2-hydroxy-3-morpholinopropanesulfonic acid (M Examples include 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), and 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid (EPPS). The cleaning solution of this embodiment does not need to contain a buffering agent, nor does it need to contain one or more of the compounds exemplified as specific examples of buffering agents.

[0040] Organic solvents The cleaning solution of this embodiment may contain an organic solvent, to the extent that it does not impair the effects of the present invention. A water-soluble organic solvent is preferred. The inclusion of an organic solvent makes it easier to remove organic residues such as polymers. Examples of water-soluble organic solvents 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, 2-methyl-2,4-pentanediol, and 3-methoxy-3-methyl-1-butanol; dimethyl sulfoxides; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and propylene glycol dimethyl ether; and morpholins such as N-methylmorpholine N-oxide.

[0041] Organic solvents may be used individually or in combination of two or more types. If the cleaning solution of this embodiment contains an organic solvent, the range of the organic solvent content is preferably 0.05 to 50% by mass, more preferably 0.1 to 30% by mass, even more preferably 0.1 to 20% by mass, and particularly preferably 0.1 to 10% by mass, relative to the sum of the amount of water and the amount of organic solvent. The cleaning solution of this embodiment does not need to contain an organic solvent or a water-soluble organic solvent, and does not need to contain one or more of the compounds exemplified as specific examples of water-soluble organic solvents.

[0042] <<Surfactants>> The cleaning solution of this embodiment may contain a surfactant for purposes such as adjusting the wettability of the cleaning solution to the substrate. Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.

[0043] Examples of nonionic surfactants include polyalkylene oxide alkylphenyl ether surfactants, polyalkylene oxide alkyl ether surfactants, block polymer surfactants consisting of polyethylene oxide and polypropylene oxide, polyoxyalkylene distyrene-phenyl ether surfactants, polyalkylene rivenzyl phenyl ether surfactants, and acetylene polyalkylene oxide surfactants.

[0044] Examples of anionic surfactants include alkyl sulfonic acid, alkylbenzene sulfonic acid, alkylnaphthalene sulfonic acid, alkyldiphenyl ether sulfonic acid, fatty acid amide sulfonic acid, polyoxyethylene alkyl ether carboxylic acid, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl ether propionic acid, alkylphosphonic acid, and fatty acid salts. Examples of "salts" include ammonium salts, sodium salts, potassium salts, and tetramethylammonium salts.

[0045] Examples of cationic surfactants include alkylpyridium surfactants and quaternary ammonium salt surfactants.

[0046] Examples of amphoteric surfactants include betaine-type surfactants, amino acid-type surfactants, imidazoline-type surfactants, and amine oxide-type surfactants.

[0047] These surfactants are generally commercially available. Surfactants may be used individually or in combination of two or more. If the cleaning solution of this embodiment contains a surfactant, the amount of surfactant is not particularly limited, but for example, 0.0001% to 5% by mass is preferred, 0.0002% to 3% by mass is more preferred, 0.002% to 1% by mass is even more preferred, and 0.002% to 0.2% by mass is particularly preferred, based on the total mass of the cleaning solution.

[0048] The cleaning solution of this embodiment does not have to contain one or more surfactants selected from the group consisting of nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants, nor does it have to contain one or more of the compounds exemplified as such surfactants. The cleaning solution of this embodiment does not have to contain any surfactants at all.

[0049] pH adjuster The cleaning solution of this embodiment may contain a pH adjuster to adjust it to a desired pH. Inorganic acids, organic acids, organic basic compounds, and inorganic basic compounds can be used as appropriate pH adjusters.

[0050] ≪Impurities, etc.≫ The cleaning solution of this embodiment may contain metallic impurities, such as metal atoms including Fe atoms, Cr atoms, Ni atoms, Zn atoms, Ca atoms, or Pb atoms. The total content of metal atoms in the cleaning solution of this embodiment is preferably 100 mass ppt or less relative to the total mass of the cleaning solution. The lower limit of the total content of metal atoms is preferable as it is lower, but for example, 0.001 mass ppt or more is acceptable. For example, the total content of metal atoms can range from 0.001 mass ppt to 100 mass ppt. By setting the total content of metal atoms to or below the preferred upper limit, the defect suppression and residue suppression properties of the cleaning solution are improved. By setting the total content of metal atoms to or above the preferred lower limit, it is considered that metal atoms are less likely to be released and exist in the system, thus reducing the likelihood of adverse effects on the overall manufacturing yield of the object being cleaned. The content of metal impurities can be adjusted, for example, by purification treatment such as filtering. This purification treatment may be performed on some or all of the raw materials before preparing the washing solution, or after preparing the washing solution.

[0051] The cleaning solution of this embodiment may contain, for example, impurities of organic origin (organic impurities). The total content of the organic impurities in the cleaning solution of this embodiment is preferably 5000 ppm by mass or less. The lower limit of the organic impurity content is preferable as it is lower, but for example, 0.1 ppm by mass or more is acceptable. The total content of organic impurities can range from 0.1 ppm by mass to 5000 ppm by mass.

[0052] The cleaning solution of this embodiment may contain countable particles of a size that can be counted by, for example, a light scattering type liquid particle counter. The size of the countable particles is, for example, 0.04 μm or larger. The number of countable particles in the cleaning solution of this embodiment is, for example, 1,000 or less per 1 mL of cleaning solution, with a lower limit of, for example, 1 or more. It is believed that the metal corrosion suppression effect of the cleaning solution is improved when the number of countable particles in the cleaning solution is within the above range.

[0053] The aforementioned organic impurities and / or substances to be counted may be added to the cleaning solution, or they may be inevitably introduced into the cleaning solution during the manufacturing process of the cleaning solution. Examples of cases where organic impurities are inevitably introduced during the manufacturing process of the cleaning solution include, but are not limited to, cases where organic impurities are contained in the raw materials used in the manufacture of the cleaning solution (e.g., organic solvents), and cases where they are introduced from the external environment during the manufacturing process of the cleaning solution (e.g., contamination). When adding the substance to be measured to the cleaning solution, the ratio of each specific size may be adjusted considering the surface roughness of the object to be cleaned.

[0054] <pH of the cleaning solution> The pH of the cleaning solution in this embodiment is preferably 8.0 or higher, and more preferably 8.0 or higher and less than 14.0, as measured at 23°C. When the pH of the cleaning solution is above the lower limit of the preferred range mentioned above, the effectiveness of removing dry etching residue during the cleaning process is enhanced.

[0055] The pH of the cleaning solution is the value measured by a pH meter at 23°C under normal pressure (1 atmosphere).

[0056] Examples of suitable cleaning solutions for this embodiment include the following embodiments (1-1) and (1-2). Embodiment (1-1): A washing solution containing hydroxyurea (where -R in formula (a1) is -NH2), at least one base selected from the group consisting of amines and ammonium compounds other than compound (A), and water. Embodiments (1-2): Washing solution containing N-(tert-butoxycarbonyl)hydroxylamine (where -R is -OC(CH3)3 in formula (a1)), at least one base selected from the group consisting of amines and ammonium compounds other than compound (A), and water.

[0057] Regarding Embodiment (1-1): The washing solution of embodiment (1-1) contains hydroxyurea, at least one base selected from the group consisting of amines and ammonium compounds other than compound (A), and water as a residue, and may contain optional components as needed. Among the bases, it is preferable to use at least one selected from the group consisting of ammonia, quaternary amine hydroxides, alkanolamines, and triamines, and it is more preferable to use at least one selected from the group consisting of ammonia, tetraethylammonium hydroxide, monoethanolamine, and diethylenetriamine.

[0058] The hydroxyurea content in the washing solution of Embodiment (1-1) is preferably 0.02% to 20% by mass, more preferably 0.2% to 15% by mass, and even more preferably 0.5% to 10% by mass, based on the total mass of the washing solution. The base content in the cleaning solution of Embodiment (1-1) is preferably 0.003% to 15% by mass, more preferably 0.03% to 13% by mass, even more preferably 0.2% to 12% by mass, and particularly preferably 0.5% to 10% by mass, based on the total mass of the cleaning solution. In the washing solution of Embodiment (1-1), the base content is preferably 15 to 5000 parts by mass, more preferably 20 to 2500 parts by mass, and even more preferably 50 to 1000 parts by mass, per 100 parts by mass of hydroxyurea.

[0059] The pH of the washing solution in embodiment (1-1) is preferably 9.0 or higher, more preferably 9.5 or higher and less than 14.0, and even more preferably 10.0 or higher and 13.6 or lower, as measured at 23°C.

[0060] Regarding Embodiments (1-2): The washing solution of Embodiments (1-2) contains N-(tert-butoxycarbonyl)hydroxylamine, at least one base selected from the group consisting of amines other than compound (A) and ammonium compounds, and water as a residue, and may contain optional components as needed. Among the bases, it is preferable to use at least one selected from the group consisting of ammonia, quaternary amine hydroxides, alkanolamines, and triamines; more preferably, at least one selected from the group consisting of ammonia, quaternary amine hydroxides, and alkanolamines; and even more preferably, at least one selected from the group consisting of ammonia, tetraethylammonium hydroxide, and monoethanolamine.

[0061] The content of N-(tert-butoxycarbonyl)hydroxylamine in the cleaning solution of Embodiments (1-2) is preferably 0.02% to 15% by mass, more preferably 0.3% to 10% by mass, and even more preferably 0.4% to 5% by mass, based on the total mass of the cleaning solution. The base content in the cleaning solution of Embodiments (1-2) is preferably 0.003% to 15% by mass, more preferably 0.03% to 13% by mass, even more preferably 0.2% to 12% by mass, and particularly preferably 0.5% to 10% by mass, based on the total mass of the cleaning solution. In the washing solution of Embodiments (1-2), the base content is preferably 15 to 5000 parts by mass, more preferably 20 to 2500 parts by mass, and even more preferably 50 to 1000 parts by mass, per 100 parts by mass of N-(tert-butoxycarbonyl)hydroxylamine.

[0062] The pH of the washing solution in Embodiments (1-2) is preferably 8.0 or higher, more preferably 8.5 or higher and less than 14.0, and even more preferably 9.0 or higher and 13.8 or lower, as measured at 23°C.

[0063] The method for storing the cleaning solution in this embodiment is not particularly limited, and conventionally known storage containers can be used. The void ratio within the container and / or the type of gas used to fill the voids should be set appropriately to ensure the stability of the cleaning solution. For example, the void ratio within the storage container can be approximately 0.01 to 30 volume percent. The cleaning solution of this embodiment can be used, for example, in the (second embodiment: method for cleaning a substrate) described later.

[0064] As described above, the cleaning solution of this embodiment contains compound (A) represented by general formula (a1) and at least one base selected from the group consisting of amines and ammonium compounds other than compound (A). This allows for effective cleaning and removal of etching residue originating from the HM layer while protecting the metal wiring layer in devices with etching residue containing inorganic materials. Therefore, it can be suitably applied to cleaning substrates (substrates, devices) after dry etching has been performed by the wiring process. In addition, since compound (A) is used as the residue remover in the cleaning solution of this embodiment, its safety is enhanced compared to conventional hydroxylamine. Furthermore, hydroxylamine is an explosive compound, classified as a Class 5 hazardous material (self-reactive substance) under the Fire Service Act, and designated as a poisonous substance under the Poisonous and Deleterious Substances Control Act.

[0065] (Second aspect: Method for cleaning a circuit board) A second aspect of the present invention relates to a substrate cleaning method, which includes a step (P1) of cleaning a substrate with etching residue containing inorganic matter using a cleaning solution according to the first aspect. In the cleaning method according to this embodiment, the substrate to be cleaned, which has etching residue attached, includes the substrate alone and elements equipped with the substrate.

[0066] The element may be one in which the metal wiring layer has been dry-etched, for example, by a semi-damascene process. Alternatively, the element may be one in which the metal wiring layer is exposed after the Si-containing layer (e.g., a Si-containing interlayer insulating film) has been dry-etched in the wiring process. Furthermore, the element may be a substrate in which the metal wiring layer is exposed after the CMP process in the wiring process. The metal wiring layer is preferably a layer containing at least one metal selected from the group consisting of molybdenum, tungsten, ruthenium, copper, iron, nickel, aluminum, lead, zinc, tin, tantalum, magnesium, cobalt, bismuth, cadmium, titanium, zirconium, antimony, manganese, beryllium, chromium, germanium, vanadium, gallium, hafnium, indium, niobium, rhenium, and thallium.

[0067] Hereinafter, an embodiment of the substrate cleaning method according to this embodiment will be described with reference to the drawings.

[0068] Figure 1 shows an example of a device (substrate / metal wiring layer / interlayer insulating film / HM layer) that will be cleaned after dry etching. In the element 100 shown in Figure 1, the substrate 10, the metal wiring layer 20, the etching stop layer 30, and the interlayer insulating film 40 are stacked in this order, and a hard mask layer (HM layer) 50 is formed on the interlayer insulating film 40. This element 100 is the result of dry etching performed by the wiring process, that is, the state after dry etching of the interlayer insulating film 40 using the HM layer 50, on which the original wiring pattern was formed by dry etching, as a mask. Dry etching residue 60 is attached to the sides of the HM layer 50 and the interlayer insulating film 40. In the spaces between the interlayer insulating films 40 in the shape of a wiring pattern, the metal wiring layer 20 is exposed, and dry etching residue 60 is also attached. The substrate 10 is made of a material such as silicon, amorphous silicon, or glass. The metal wiring layer 20 is a wiring layer made of metals such as molybdenum, tungsten, ruthenium, copper, iron, nickel, aluminum, lead, zinc, tin, tantalum, magnesium, cobalt, bismuth, cadmium, titanium, zirconium, antimony, manganese, beryllium, chromium, germanium, vanadium, gallium, hafnium, indium, niobium, rhenium, and thallium. The interlayer insulating film 40 is made of silicon-based materials such as SiO2, SiN, and SiOC. The HM layer 50 is made of titanium-based materials such as titanium nitride (TiN) and titanium oxide (TiOx). The dry etching residue 60 is mainly a Ti-containing residue containing titanium-based materials derived from the HM layer 50.

[0069] [Washing process (P1)] This step (P1) is a step of cleaning the element 100 after dry etching has been performed by the wiring process using a cleaning solution according to the first embodiment. The cleaning method is not particularly limited, and known cleaning methods can be used. When bringing the cleaning solution into contact with the element 100 to be cleaned, the cleaning solution may be diluted 2 to 2000 times to obtain a diluted solution, and then the cleaning operation may be performed using this diluted solution. Examples of cleaning methods include continuously applying cleaning solution onto the element 100 while it is rotating at a constant speed (rotary coating method), immersing the element 100 in cleaning solution for a certain period of time (dip method), and spraying cleaning solution onto the surface of the element 100 (spray method).

[0070] The temperature at which the cleaning process is performed is not particularly limited. The cleaning process is preferably carried out under conditions of 10 to 80°C, but may also be 20 to 75°C or 40 to 70°C. Increasing the temperature of the cleaning solution improves the removal of etching residue. However, the temperature of the cleaning solution can be selected as appropriate, taking into consideration factors such as minimizing changes in the composition of the cleaning solution, workability, safety, and cost.

[0071] The cleaning time can be appropriately selected to be sufficient to remove etching residue, impurities, etc., adhering to the surface of element 100. For example, the cleaning time may be 10 seconds to 30 minutes, 20 seconds to 15 minutes, 30 seconds to 10 minutes, or 30 seconds to 5 minutes.

[0072] According to the cleaning method of this embodiment described above, since cleaning is performed using the cleaning solution according to the first embodiment, the dry etching residue 60 originating from the HM layer 50 can be effectively cleaned and removed from the element 100 with dry etching residue 60 attached, while suppressing damage to the metal wiring layer 20. Furthermore, according to the cleaning method of this embodiment, damage to the interlayer insulating film 40 can also be suppressed. In addition, since compound (A) is used as a residue remover in the cleaning solution, semiconductor devices and the like can be manufactured more safely compared to conventional hydroxylamine.

[0073] (Third aspect: Method for manufacturing semiconductor devices) A third aspect of the present invention relates to a method for manufacturing a semiconductor device, which includes a step (P1) of cleaning a substrate with etching residue containing inorganic material using a cleaning solution according to the first aspect.

[0074] One embodiment of a semiconductor device manufacturing method is a manufacturing method that includes the above-mentioned step (P1) and an optional step. In the manufacturing method according to this embodiment, step (P1) can be carried out in the same manner as the method described in the [cleaning step (P1)] in the (second embodiment: substrate cleaning method) described above. Optional processes include hard mask layer etching, wiring layer dry etching, and contact etching, which may be performed before process (P1). Furthermore, optional processes include known processes performed when manufacturing semiconductor devices, such as capacitor formation, channel formation, High-K / metal gate formation, metal wiring, gate structure, source structure, drain structure, insulating layer, ferromagnetic layer, and non-magnetic layer formation processes (layer formation, etching other than the above etching processes, chemical mechanical polishing, modification, etc.), resist film formation processes, exposure processes, development processes, heat treatment processes, and inspection processes.

[0075] The semiconductor device manufacturing method of this embodiment described above includes a step (P1) of cleaning a substrate with etching residue containing inorganic matter using a cleaning solution according to the first embodiment. This allows for effective removal of etching residue while minimizing damage to metal wiring. As a result, the electrical characteristics of the manufactured semiconductor device are improved. [Examples]

[0076] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The components used in the examples and comparative examples are shown below.

[0077] • Residue remover (A)-1: Hydroxyurea (A)-2: N-Boc-HA (N-(tert-butoxycarbonyl)hydroxylamine) (A)-3: Hydroxylamine (A)-4: Hydrogen peroxide

[0078] [ka]

[0079] ·base (B)-1: Ammonia (B)-2: Tetraethylammonium hydroxide (B)-3: Monoethanolamine (B)-4: Diethylenetriamine

[0080] [ka]

[0081] • pH adjuster (C)-1: Citric acid ·solvent (S)-1:Water (S)-2: Glycerin

[0082] <Preparation of cleaning solution> (Examples 1-13, Comparative Examples 1-4; Examples 14-25, Comparative Examples 5-8) Washing solutions for each example were prepared using the components shown in Tables 1 and 2. In Tables 1 and 2, each abbreviation has the meaning described above. The numbers in brackets [ ] indicate the percentage (mass %) of each component relative to the total mass of the cleaning solution.

[0083] [pH of the cleaning solution] The pH of the washing solution was measured at a temperature of 23°C using a pH meter (portable pH meter D-73S, manufactured by Horiba, Ltd.). The results are shown in Tables 1 and 2 as "pH (23°C)".

[0084] <Rating> For each example of the cleaning solution, the ability to remove etching residue and reduce metal damage was evaluated using the etching rate as an indicator, as follows.

[0085] [Measurement of etching rate] The substrate used was a 12-inch silicon substrate on which a 50 nm thick titanium nitride (TiN) film, a 100 nm thick tungsten (W) film, and a 50 nm thick molybdenum (Mo) film were deposited by PVD (Physical Vapor Deposition).

[0086] The deposited substrate was cut into 2cm x 2cm pieces to create wafer coupons. 100 mL of the cleaning solution for each example was placed in a 200 mL beaker, heated to the specified processing temperature shown in the table, and the cut wafer coupons were immersed in the cleaning solution. While the wafer coupons were immersed in the cleaning solution, the mixture was stirred at 300 rpm at the specified processing temperature shown in the table. After immersion for 60 minutes, the wafer coupons were removed from the cleaning solution, rinsed with water at room temperature for 30 seconds, and dried by nitrogen blowing. The film thickness of the wafer coupon was measured before and after immersion in the cleaning solution. The film thicknesses of wafer coupons containing TiN, W, and Mo films were measured using an X-ray fluorescence spectrometer (ZSX PrimusIV, Rigaku). The etching rate was then calculated from the changes in the film thickness of the TiN, W, and Mo films before and after the cleaning process.

[0087] • Evaluation of the ease of removing etching residue The removal efficiency of etching residues was evaluated using the etching rate of the cleaning solution against the TiN film as an indicator, according to the following evaluation criteria. The results are shown in Tables 1 and 2. A higher etching rate means better removal of etching residue.

[0088] • Criteria for evaluating the ease of removing etching residue The etching rate of the cleaning solution against the TiN film is A: 0.4 × 10 -10 It exceeds m / min. B: 0.1 × 10 -10 m / min or more 0.4×10 -10 It is less than or equal to m / min. C:0.1×10 -10 It is less than m / min.

[0089] • Evaluation of the ability to reduce metal damage The reduction of metal damage was evaluated using the etching rate of the cleaning solution against the W film (W ER) and the etching rate of the cleaning solution against the Mo film (Mo ER) as indicators. The values ​​for each etching rate are shown in Tables 1 and 2. A lower etching rate value means less damage to the metal (e.g., metal wiring).

[0090] [Table 1]

[0091] [Table 2]

[0092] The results shown in Tables 1-2 confirm that when the cleaning solutions of Examples 1-13 and 14-25, to which the present invention was applied, both the ability to remove etching residue and the reduction of metal damage were good. On the other hand, when using the cleaning solutions of Comparative Examples 1, 2, 4, 5, 6, and 8, which are outside the scope of the present invention, either the ability to remove etching residue or the ability to reduce metal damage was inferior.

[0093] Furthermore, in the cleaning solutions of Comparative Examples 3 and 7, hydroxylamine is used as a residue remover. In the cleaning solutions of Examples 1 to 13 and Examples 14 to 25, the residue remover is replaced with compound (A), thereby improving safety.

[0094] While preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications to the configuration are possible without departing from the spirit of the invention. The present invention is not limited by the foregoing description, but only by the appended claims. [Explanation of Symbols]

[0095] 10 Substrate, 20 Metal wiring layer, 30 Etching stop layer, 40 Interlayer insulating film, 50 Hard mask layer (HM layer), 60 Dry etching residue, 100 Element

Claims

1. A cleaning solution for removing etching residue containing inorganic materials, Compound (A) represented by the following general formula (a1), At least one base selected from the group consisting of amines and ammonium compounds other than the aforementioned compound (A), A cleaning solution containing [a specific ingredient]. 【Chemistry 1】 [In the formula, -R is -NH ２ or -O-C(CH ３ ) ３ That is the case.

2. The washing solution according to claim 1, wherein the pH measured at 23°C is 8.0 or higher.

3. The washing solution according to claim 1, wherein the base is at least one selected from the group consisting of ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, alkanolamine, and triamine.

4. The washing solution according to claim 1, wherein the content of the base is 15 to 5000 parts by mass per 100 parts by mass of compound (A).

5. The cleaning solution according to claim 1, used for cleaning a substrate after dry etching has been performed by a wiring process.

6. A method for cleaning a substrate, comprising the step (P1) of cleaning a substrate with etching residue containing inorganic matter using a cleaning solution according to any one of claims 1 to 5.

7. The method for cleaning a substrate according to claim 6, wherein in step (P1), the operation of cleaning the substrate using the cleaning solution is performed under conditions of 10 to 80°C.

8. The method for cleaning a substrate according to claim 6, wherein the substrate is a substrate that has been dry-etched by a wiring process.

9. A method for manufacturing a semiconductor device, comprising the step (P1) of cleaning a substrate with etching residue containing inorganic material using a cleaning solution according to any one of claims 1 to 5.

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