Chemical solution, treatment method

Abstract

To provide a chemical liquid which is improved in etching capacity of an Al oxide, improved in suppression property of etching capacity of a Ga oxide and also improved in etching selectivity of the Ai oxide with respect to the Ga oxide, and a processing method using the chemical liquid.SOLUTION: The present invention relates to a chemical liquid containing phosphoric acid or salt thereof, a non-protonic polar solvent, water and a compound having a carboxy group and not having a hydroxy group or salt thereof. A content of the phosphoric acid or the salt thereof is 5.0 mass% or less with respect to a total mass of the chemical liquid. A content of the non-protonic polar solvent is 50.0 mass% or more with respect to the total mass of the chemical liquid. A content of the water is 2.0 mass% or more and less than 50.0 mass% with respect to the total mass of the chemical liquid.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a chemical solution and a treatment method.

Background Art

[0002] As semiconductor products are miniaturized, there is an increasing demand for efficiently and accurately performing a process of removing unnecessary transition metal inclusions on a substrate in the manufacturing process of semiconductor products. For example, as a process of removing unnecessary metal oxides containing Al (hereinafter also referred to as "Al oxides") on a substrate, for example, a method of etching using a chemical solution that dissolves unnecessary Al oxides or removing foreign substances attached to the solid surface is widely known.

[0003] For example, Patent Document 1 discloses "(a) at least one water-soluble or water-miscible organic solvent, (b) at least one non-neutralized inorganic phosphorus-containing acid, and (c) water, and does not contain an organic amine, hydroxylamine, and strong base that neutralize the inorganic phosphorus-containing acid component, a composition for cleaning a microelectronic substrate."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As the required performance of the above chemical solution, in addition to being excellent in the etching ability of unnecessary Al oxides, it is also possible to suppress the etching ability of metal oxides containing necessary Ga (hereinafter also referred to as "Ga oxides") that are non-removal targets, and excellent in the etching selectivity of Al oxides with respect to Ga oxides. In order to dissolve unnecessary Al oxide, there is also a method of extending the contact time between the chemical solution and the object to be treated. In such a case, as the contact time with the chemical solution is prolonged, in addition to unnecessary Al oxide, necessary Ga oxide is often dissolved. Therefore, it is particularly required to have excellent etching selectivity of Al oxide with respect to Ga oxide. The etching selectivity of Al oxide with respect to Ga oxide means that when treating an object to be treated with a chemical solution, unnecessary Al oxide can be selectively etched. More specifically, when removing Al oxide, it means that the ratio of the etching rate of Al oxide, which is the object to be removed, to the etching rate of Ga oxide, which is not the object to be removed (etching rate of Al oxide / etching rate of Ga oxide) is large.

[0006] When the present inventors examined the chemical solution and the like described in Patent Document 1, they found that at least one of the etching ability of Al oxide, the inhibitory ability of the etching ability of Ga oxide, and the etching selectivity of Al oxide with respect to Ga oxide was inferior.

[0007] Therefore, an object of the present invention is to provide a chemical solution that is excellent in the etching ability of Al oxide, excellent in the inhibitory ability of the etching ability of Ga oxide, and also excellent in the etching selectivity of Al oxide with respect to Ga oxide. Another object of the present invention is also to provide a treatment method using the above chemical solution.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following configuration.

[0009] 〔1〕 A chemical solution containing phosphoric acid or its salt, an aprotic polar solvent, water, and a compound having a carboxy group and no hydroxyl group or its salt, The content of the above phosphoric acid or its salt is 5.0% by mass or less with respect to the total mass of the above chemical solution, The content of the above aprotic polar solvent is 50.0% by mass or more based on the total mass of the above chemical solution, The chemical solution, wherein the content of the above water is 2.0% by mass or more and less than 50.0% by mass based on the total mass of the above chemical solution. 〔2〕 The chemical solution according to 〔1〕, wherein the content of the above phosphoric acid or its salt is 3.0% by mass or less based on the total mass of the above chemical solution. 〔3〕 The chemical solution according to 〔1〕 or 〔2〕, wherein the above aprotic polar solvent contains at least one solvent selected from the group consisting of sulfolane, dimethyl sulfoxide, and ether solvents. 〔4〕 The chemical solution according to any one of 〔1〕 to 〔3〕, wherein the above aprotic polar solvent contains sulfolane. 〔5〕 The chemical solution according to any one of 〔1〕 to 〔4〕, wherein the mass ratio of the content of the above aprotic polar solvent to the content of the above phosphoric acid or its salt is more than 40. 〔6〕 The chemical solution according to any one of 〔1〕 to 〔5〕, wherein the mass ratio of the content of the above aprotic polar solvent to the content of the above phosphoric acid or its salt is more than 80. 〔7〕 The chemical solution according to any one of 〔1〕 to 〔6〕, wherein the content of the above water is 2.0 to 30.0% by mass based on the total mass of the above chemical solution. 〔8〕 The chemical solution according to any one of 〔1〕 to 〔7〕, wherein the content of the above water is 2.0 to 15.0% by mass based on the total mass of the above chemical solution. 〔9〕 The chemical solution according to any one of 〔1〕 to 〔8〕, wherein the content of the above water is 2.0 to 10.0% by mass based on the total mass of the above chemical solution. 〔10〕 The chemical solution according to any one of 〔1〕 to 〔9〕, wherein the above compound having a carboxy group and no hydroxy group or its salt contains at least one compound selected from the group consisting of a compound represented by the following formula (C1) and a compound having a repeating unit represented by the following formula (C2). 〔11〕 The chemical solution according to any one of [1] to

[10] , wherein the compound having a carboxy group and no hydroxy group or a salt thereof contains at least one compound selected from the group consisting of acetic acid, malonic acid, succinic acid, glutaric acid, octanoic acid, 2-ethylhexanoic acid, poly(meth)acrylic acid, and salts thereof.

[12] The chemical solution according to any one of [1] to

[11] , which substantially does not contain fluoride.

[13] The chemical solution according to any one of [1] to

[12] , which substantially does not contain hydrogen peroxide.

[14] The chemical solution according to any one of [1] to

[13] , which substantially does not contain polishing particles.

[15] The chemical solution according to any one of [1] to

[14] , having a pH of 2 or less.

[16] The chemical solution according to any one of [1] to

[15] , which is used for an object to be processed containing a metal oxide containing Al and a metal oxide containing Ga.

[17] The chemical solution according to any one of [1] to

[16] , which is used as an etching solution.

[18] A treatment method, comprising a step of bringing an object to be processed containing a metal oxide containing Al and a metal oxide containing Ga into contact with the chemical solution according to any one of [1] to

[17] .

[19] The treatment method according to

[18] , wherein the temperature of the chemical solution is 40 to 80°C. [Advantages of the Invention]

[0010] According to the present invention, it is possible to provide a chemical solution excellent in the etching ability of an Al oxide, excellent in the suppressibility of the etching ability of a Ga oxide, and also excellent in the etching selectivity of the Al oxide with respect to the Ga oxide. Further, according to the present invention, it is possible to provide a method for treating a substrate using the above chemical solution. [Embodiments for Carrying Out the Invention]

[0011] Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.

[0012] Hereinafter, the meaning of each description in this specification will be shown. A numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. "Preparation" includes procuring a predetermined item by purchase or the like, in addition to synthesizing and formulating specific materials. When two or more kinds of a certain component are present, the "content" of that component means the content of those two or more kinds of components, unless otherwise specified. "Main component" means the component with the largest content.

[0013] "ppm" means parts-per-million (10 -6 ). "ppt" means parts-per-trillion (10 -12 ). "Radiation" means the emission line spectrum of a mercury lamp, far ultraviolet rays typified by an excimer laser, extreme ultraviolet rays (EUV light), X-rays, or electron beams. "Light" means actinic rays or radiation. "Exposure" includes, unless otherwise specified, exposure by far ultraviolet rays typified by a mercury lamp or an excimer laser, X-rays, or EUV light, and drawing by particle beams such as electron beams or ion beams.

[0014] "(Meth)acrylic acid" is a concept encompassing both acrylic acid and methacrylic acid. In the description of a compound, the compound may include, unless otherwise specified, structural isomers (compounds having the same number of atoms but different structures), optical isomers, and isotopes. Also, the structural isomers, optical isomers, and isotopes may include one kind or two or more kinds. In the case where Y in the compound represented by "X-Y-Z" is -COO- (where the divalent group is, for example, -COO-), the bonding direction of the divalent group may be either "X-O-CO-Z" or "X-CO-O-Z" unless otherwise specified.

[0015] [Chemical solution] The chemical solution is a chemical solution containing phosphoric acid or a salt thereof, an aprotic polar solvent, water, and a compound having a carboxy group and no hydroxy group, where the content of phosphoric acid or a salt thereof is 5.0% by mass or less based on the total mass of the chemical solution, the content of the aprotic polar solvent is 50.0% by mass or more based on the total mass of the chemical solution, and the content of water is 2.0% by mass or more and less than 50.0% by mass based on the total mass of the chemical solution.

[0016] Although the mechanism by which the above problems are solved by the chemical solution having the above configuration is not necessarily clear, the inventors consider as follows. In the chemical solution, phosphoric acid or a salt thereof has a function of improving the etching ability of Al oxide, and the aprotic polar solvent and the specific compound have a function of suppressing the etching ability of Ga oxide. By determining the predetermined amounts of these various components, as a result of adjusting the etching abilities of Al oxide and Ga oxide, it is presumed that the etching ability of Al oxide is excellent, the suppression of the etching ability of Ga oxide is excellent, and the etching selectivity of Al oxide with respect to Ga oxide is excellent. Hereinafter, obtaining at least one of the effects of excellent etching ability of Al oxide, excellent suppression of the etching ability of Ga oxide, and excellent etching selectivity of Al oxide with respect to Ga oxide is also referred to as "excellent effects of the present invention".

[0017] [Various components] Hereinafter, the components that can be contained in the chemical solution will be described in detail.

[0018] [Phosphoric acid or a salt thereof] The chemical solution contains phosphoric acid or a salt thereof. The content of phosphoric acid or its salt is 5.0% by mass or less, preferably 3.0% by mass or less, and more preferably 1.0% by mass or less, based on the total mass of the chemical solution. The lower limit is preferably more than 0% by mass, more preferably 0.1% by mass or more, and still more preferably 0.5% by mass or more, based on the total mass of the chemical solution. Examples of the method for measuring the content of phosphoric acid or its salt include known measurement methods such as ion chromatography and capillary electrophoresis.

[0019] Examples of phosphoric acid include orthophosphoric acid (H 3 PO 4 ), diphosphoric acid, metaphosphoric acid, and polyphosphoric acid, with orthophosphoric acid being preferred. Examples of phosphates include metal salts, and salts of alkali metals such as sodium and potassium, salts of alkaline earth metals such as calcium and magnesium, and aluminum salts are preferred. In addition, phosphoric acid may form salts with various other components contained in the chemical solution.

[0020] Phosphoric acid or its salt may be used alone or in combination of two or more.

[0021] <Aprotic polar solvent> The chemical solution contains an aprotic polar solvent. The content of the aprotic polar solvent is 50.0% by mass or more, preferably 60.0% by mass or more, more preferably 70.0% by mass or more, and still more preferably 75.0% by mass or more, based on the total mass of the chemical solution. The upper limit is preferably 95.0% by mass or less, and more preferably 90.0% by mass or less, based on the total mass of the chemical solution. Examples of the method for measuring the content of the aprotic polar solvent include known measurement methods such as gas chromatography and liquid chromatography.

[0022] Examples of the aprotic polar solvent include sulfolane-based solvents, sulfoxide-based solvents, ether-based solvents, and amide-based solvents.

[0023] Examples of the sulfolane-based solvents include, for example, sulfolane, methyl sulfolane, and dimethyl sulfolane, with sulfolane being preferred.

[0024] Examples of the sulfoxide-based solvents include, for example, dimethyl sulfoxide.

[0025] Examples of the ether-based solvents include, for example, glycol ethers, glycol diethers, and cyclic ethers. Preferred glycol ethers are (mono / di / tri / poly)ethylene glycol alkyl ethers, ethylene glycol aryl ethers, (mono / di / tri / poly)propylene glycol alkyl ethers, or propylene glycol aryl ethers. Examples of the (mono / di / tri / poly)ethylene glycol alkyl ethers include, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, ethylene glycol monomethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and polyethylene glycol monomethyl ether. "(Mono / di / tri / poly)ethylene glycol" is a concept encompassing monoethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol. Examples of the ethylene glycol aryl ethers include, for example, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, and diethylene glycol monobenzyl ether.

[0026] Examples of (mono / di / tri / poly)propylene glycol alkyl ethers include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, and polypropylene glycol monomethyl ether. “(Mono / di / tri / poly)propylene glycol” is a concept that includes monopropylene glycol, dipropylene glycol, tripropylene glycol, and polypropylene glycol. Examples of propylene glycol aryl ethers include propylene glycol monophenyl ether, propylene glycol monobenzyl ether, and dipropylene glycol monobenzyl ether.

[0027] As the glycol diether, (mono / di / tri / poly)ethylene glycol dialkyl ether or (mono / di / tri / poly)propylene glycol dialkyl ether is preferred. Examples of (mono / di / tri / poly)ethylene glycol dialkyl ethers include tetraethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol butyl methyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and. As the (mono / di / tri / poly)ethylene glycol dialkyl ether, tetraethylene glycol dimethyl ether, diethylene glycol diethyl ether, or diethylene glycol butyl methyl ether is preferred.

[0028] Examples of (mono / di / tri / poly)propylene glycol dialkyl ethers include tetrapropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol butyl methyl ether, dipropylene glycol dibutyl ether, tripropylene glycol butyl methyl ether, dipropylene glycol ethyl methyl ether, dipropylene glycol dimethyl ether, propylene glycol dimethyl ether, polypropylene glycol dimethyl ether, tripropylene glycol dimethyl ether, etc. As the (mono / di / tri / poly)propylene glycol dialkyl ether, tetrapropylene glycol dimethyl ether, dipropylene glycol diethyl ether or dipropylene glycol butyl methyl ether is preferable.

[0029] Examples of the cyclic ether include 1,4-dioxane and 1,3-dioxolane.

[0030] Examples of the amide solvents include N,N-dimethylformamide, 1-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidinone, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropanamide and hexamethylphosphoric triamide.

[0031] The aprotic polar solvent preferably contains at least one solvent selected from the group consisting of sulfolane solvents, sulfoxide solvents and ether solvents, more preferably contains at least one solvent selected from the group consisting of sulfolane, dimethyl sulfoxide and ether solvents, still more preferably contains at least one solvent selected from the group consisting of sulfolane, dimethyl sulfoxide and glycol diethers, and particularly preferably contains sulfolane.

[0032] The aprotic polar solvent may be used alone or in combination of two or more.

[0033] The mass ratio of the content of the aprotic polar solvent to the content of phosphoric acid or its salt (content of aprotic polar solvent / content of phosphoric acid or its salt) is preferably more than 40, more preferably more than 80. The upper limit is not particularly limited, but is often 100 or less.

[0034] <Water> The chemical solution contains water. The content of water is 2% by mass or more and less than 50% by mass, preferably 2 - 30% by mass, more preferably 2 - 15% by mass, and still more preferably 2 - 10% by mass with respect to the total mass of the chemical solution. Examples of the method for measuring the content of water include known measurement methods such as the Karl Fischer method.

[0035] Examples of the water include ultrapure water used in semiconductor device manufacturing. As the water, water with reduced inorganic anions and metal ions, etc. is preferred, water with reduced ion concentration derived from metal atoms selected from Fe, Co, Na, K, Ca, Cu, Mg, Mn, Li, Al, Cr, Ni, and Zn is more preferred, and when used in the preparation of the chemical solution, water adjusted so that the content of the above metal atoms is on the order of mass ppt or less (for example, the metal content rate is less than 0.001 mass ppt, etc.) is still more preferred. Examples of the method for adjusting the content of the above metal atoms include the methods described in paragraphs

[0074] to

[0084] of JP-A-2011-110515 and the method described in JP-A-2007-254168, and purification using a filtration membrane or an ion exchange membrane or distillation purification is preferred.

[0036] As the water used in the embodiments of the present invention, the water obtained above is preferred. It is preferable that the above water is also used for washing the container described later. Further, it is also preferable that the above water is used for the manufacturing process of the chemical solution, the measurement of the components of the chemical solution, and the measurement for the evaluation of the chemical solution.

[0037] <Specific compound> The chemical solution contains a specific compound. The specific compound is a compound having a carboxy group and no hydroxyl group, or a salt thereof.

[0038] If the specific compound has a carboxy group and no hydroxyl group, it may have other functional groups, and it is more preferable to have only a carboxy group as the functional group. It is also preferable that the specific compound has none of a hydroxyl group, a primary amino group, a secondary amino group, and a tertiary amino group. The number of carboxy groups that the specific compound has is 1 or more, preferably 1 to 5, more preferably 1 to 3, and even more preferably 2.

[0039] The specific compound may be a salt, but it is preferably not a salt. Examples of the salt of the specific compound include metal salts, and salts of alkali metals such as sodium and potassium, and salts of alkaline earth metals such as calcium and magnesium are preferable. Further, the specific compound may form a salt with various other components contained in the chemical solution.

[0040] The specific compound preferably contains at least one compound selected from the group consisting of the compound represented by formula (C1) and the compound having the repeating unit represented by formula (C2), and more preferably contains the compound represented by formula (C1).

[0041] Z 1 -L 1 -(Z 2 ) n (C1) In formula (C1), Z 1 represents a hydrocarbon group, or a carboxy group or a salt thereof. L 1 represents a single bond or an (n + 1)-valent hydrocarbon group. Z 2 represents a carboxy group or a salt thereof. n represents an integer of 1 to 5. However, when L 1 represents a single bond, n represents 1.

[0042] Z 1 represents a hydrocarbon group, or a carboxy group or a salt thereof. As the hydrocarbon group, an alkyl group is preferred. The alkyl group may be linear, branched or cyclic. The number of carbon atoms of the alkyl group is preferably 1 to 20, more preferably 1 to 10, and still more preferably 1 to 3. The salt of the carboxy group is -COO - M + and M + is a monovalent cation other than H + . As M + , a monovalent metal cation or an ammonium cation is preferred, and an alkali metal cation such as sodium and potassium is more preferred. Z 1 is preferably a carboxy group.

[0043] L 1 represents a single bond or an (n + 1)-valent hydrocarbon group. As the (n + 1)-valent hydrocarbon group, a group formed by removing (n + 1) hydrogen atoms from a hydrocarbon is preferred. The hydrocarbon may be linear, branched or cyclic. The number of carbon atoms of the hydrocarbon is preferably 1 to 20, more preferably 1 to 10, and still more preferably 1 to 3. Examples of the hydrocarbon include aliphatic hydrocarbons having 1 to 20 carbon atoms (e.g., alkylene groups, etc.), aliphatic rings having 3 to 20 carbon atoms, and aromatic rings having 3 to 20 carbon atoms. Further, the hydrocarbon may be combined with at least one divalent linking group selected from the group consisting of -O-, -S-, -CO-, -NR N -(R N represents a hydrogen atom or a substituent.) and -SO 2 -.

[0044] Z 2 represents a carboxy group or a salt thereof. Z 2 is preferably a carboxy group. The salt of the carboxy group is Z 1is synonymous with the salt of the carboxy group represented by, and the preferred embodiments are also the same.

[0045] n represents an integer of 1 to 5. However, when 1 L represents a single bond, n represents 1. n is preferably an integer of 1 to 3, and more preferably 1.

[0046]

Chemical formula

[0047] In formula (C2), R 2 represents a hydrogen atom, a methyl group, a carboxy group or a salt thereof. L 2 represents a single bond or a divalent linking group. Z 3 represents a carboxy group or a salt thereof.

[0048] R 2 represents a hydrogen atom, a methyl group, a carboxy group or a salt thereof. The salt of the above carboxy group is synonymous with the salt of the carboxy group represented by Z 1 and the preferred embodiments are also the same. R 2 is preferably a hydrogen atom or a carboxy group, and more preferably a carboxy group.

[0049] L 2 represents a single bond or a divalent linking group. L 2 Examples of the divalent linking group represented by include the divalent linking group represented by L 1 and an alkylene group is preferred. The above alkylene group may be linear, branched or cyclic, and a linear one is preferred. The number of carbon atoms of the above alkylene group is preferably 1 to 20, more preferably 1 to 10, and still more preferably 1 to 3.

[0050] Z 3 represents a carboxy group or a salt thereof. Z 3As for this, a carboxy group is preferable. The salt of the above carboxy group is synonymous with the salt of the carboxy group represented by Z 1 and has the same preferred embodiments.

[0051] Examples of the specific compound include a monocarboxylic acid having no hydroxyl group, a dicarboxylic acid having no hydroxyl group, a polycarboxylic acid having no hydroxyl group, and salts thereof. Examples of the monocarboxylic acid having no hydroxyl group and salts thereof include formic acid, acetic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid, and salts thereof. Examples of the dicarboxylic acid having no hydroxyl group and salts thereof include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and salts thereof. Examples of the polycarboxylic acid having no hydroxyl group and salts thereof include trimellitic acid, poly(meth)acrylic acid, polymaleic acid, polyitaconic acid, and salts thereof. The above salts are as described above.

[0052] The specific compound preferably contains at least one compound selected from the group consisting of acetic acid, malonic acid, succinic acid, glutaric acid, octanoic acid, 2-ethylhexanoic acid, poly(meth)acrylic acid, and salts thereof, more preferably contains at least one compound selected from the group consisting of malonic acid, poly(meth)acrylic acid, and salts thereof, still more preferably contains at least one compound selected from the group consisting of malonic acid and salts thereof, and particularly preferably contains malonic acid.

[0053] The specific compound may be either a low-molecular compound or a high-molecular compound. When the specific compound is a low-molecular compound, the molecular weight of the specific compound is preferably 50 to 500, more preferably 50 to 200. When the specific compound is a polymer compound, the molecular weight of the specific compound is preferably from 1,000 to 100,000, more preferably from 2,000 to 30,000.

[0054] The specific compound may be used alone or in combination of two or more. The content of the specific compound is preferably from 0.01 to 45.0% by mass, more preferably from 5.0 to 45.0% by mass, still more preferably from 7.0 to 45.0% by mass, based on the total mass of the chemical solution.

[0055] <fluoride> From the viewpoint of excellent effects of the present invention, the chemical solution preferably does not substantially contain a fluoride. Not substantially containing a fluoride specifically means that the content of the fluoride is 1% by mass or less, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, based on the total mass of the chemical solution. The lower limit is preferably 0% by mass or more based on the total mass of the chemical solution. Examples of the fluoride include hydrofluoric acid, ammonium fluoride, tetramethylammonium fluoride, hexafluorosilicic acid, hexafluorophosphoric acid, and tetrafluoroboric acid.

[0056] <hydrogen peroxide> The chemical solution preferably does not substantially contain hydrogen peroxide. Not substantially containing hydrogen peroxide specifically means that the content of hydrogen peroxide is 1% by mass or less, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, based on the total mass of the chemical solution. The lower limit is preferably 0% by mass or more based on the total mass of the chemical solution.

[0057] <abrasive particles> The chemical solution preferably does not substantially contain abrasive particles. Not substantially containing abrasive particles specifically means that the content of the abrasive particles is 1000 ppm by mass or less, preferably 500 ppm by mass or less, more preferably 100 ppm by mass or less, based on the total mass of the chemical solution. The lower limit is preferably 0% by mass or more based on the total mass of the chemical solution. Examples of the abrasive particles include abrasive particles such as silicon oxide contained in a slurry for chemical mechanical polishing and the descriptions in paragraphs

[0194] to

[0197] of WO 2021 / 131451. Examples of the method for measuring the content of the abrasive particles include a method of measuring in a liquid phase using a commercially available measuring device in a light scattering type in-liquid particle measuring method using a laser as a light source. Examples of the method for adjusting the content of the abrasive particles include known methods such as filtering treatment.

[0058] <Optional component> In addition to the above components, the chemical solution may further contain an optional component. The optional component may be used alone or in combination of two or more.

[0059] (Basic compound) The basic compound is a compound that exhibits alkalinity (pH > 7.0) in an aqueous solution. The basic compound is a compound different from the above various components. Examples of the basic compound include organic bases, inorganic bases, and salts thereof.

[0060] Examples of the organic base include ammonium hydroxide (NH 4 OH), quaternary ammonium salts, amine compounds and their salts, nitro compounds, nitroso compounds, oxime compounds, keto-oxime compounds, aldo-oxime compounds, lactam compounds, and isocyanide compounds.

[0061] The quaternary ammonium salt is a salt having a quaternary ammonium cation in which four hydrocarbon groups are substituted on a nitrogen atom. Examples of the quaternary ammonium salt include hydroxides, fluorides, bromides, iodides, acetates, and carbonates.

[0062] Examples of the quaternary ammonium salts include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), or tetra(hydroxyethyl)ammonium hydroxide, with TMAH, TEAH, TPAH, or TBAH being more preferred.

[0063] An amine compound is a compound having an amino group in the molecule. Examples of the amine compounds include primary amines having a primary amino group (-NH 2 ) in the molecule, secondary amines having a secondary amino group (>NH) in the molecule, tertiary amines having a tertiary amino group (>N-) in the molecule, and salts thereof. Examples of the salts of the amine compounds include salts with inorganic acids formed by bonding of at least one non-metal selected from the group consisting of Cl, S, N, and P to hydrogen, with hydrochloride, sulfate, or nitrate being preferred. The amine compound is preferably a water-soluble amine that can dissolve 50 g or more in 1 L of water. Examples of the amine compounds include alicyclic amine compounds, aliphatic amines, alkanolamines, and hydroxyamine compounds.

[0064] An alicyclic amine compound is a compound having a ring structure in the molecule among the amine compounds. Examples of the alicyclic amine compounds include 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), ε-caprolactam, the following Compound 1, the following Compound 2, the following Compound 3, 1,4-diazabicyclo[2.2.2]octane (DABCO), tetrahydrofurfurylamine, N-(2-aminoethyl)piperazine, hydroxyethylpiperazine, piperazine, 2-methylpiperazine, trans-2,5-dimethylpiperazine, cis-2,6-dimethylpiperazine, 2-piperidinemethanol, cyclohexylamine, and 1,5-diazabicyclo[4,3,0]-5-nonene.

[0065] [Chemical formula]

[0066] Examples of aliphatic amine compounds include alkylamine, dialkylamine, and trialkylamine.

[0067] Trialkylamine is a compound having a tertiary amino group in which three alkyl groups are substituted on a nitrogen atom. Examples of trialkylamine include trimethylamine, triethylamine, tripropylamine, tributylamine, dimethylethylamine, dimethylpropylamine, dimethylbutylamine, diethylmethylamine, diethylpropylamine, diethylbutylamine, dipropylmethylamine, dipropylethylamine, dipropylbutylamine, dibutylmethylamine, dibutylethylamine, and dibutylpropylamine. As the trialkylamine, trimethylamine, diethylmethylamine, triethylamine or tributylamine is preferable, and trimethylamine is more preferable.

[0068] Alkanolamine is a compound having one or more hydroxyalkyl groups in the molecule among amine compounds. Alkanolamine may have any of a primary amino group, a secondary amino group, and a tertiary amino group, and preferably has a primary amino group. Examples of alkanolamines include monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), diethylene glycolamine (DEGA), tris(hydroxymethyl)aminomethane (Tris), 2-amino-2-methyl-1-propanol (AMP), 2-amino-2-methyl-1,3-dipropanol (AMPD), 2-amino-2-ethyl-1,3-dipropanol (AEPD), 2-(methylamino)-2-methyl-1-propanol (N-MAMP), 2-(aminoethoxy)ethanol (AEE), and N-(2-aminoethyl)ethanolamine (AEEA), with AEE or AEEA being preferred.

[0069] The hydroxyamine compound is at least one compound selected from the group consisting of hydroxyamine (NH 2 OH), hydroxyamine derivatives, and salts thereof. The hydroxyamine compound has a function of promoting the decomposition and solubilization of residues and removing residues such as etching residues and ashing residues.

[0070] Examples of hydroxyamine derivatives include O-methylhydroxyamine, O-ethylhydroxyamine, N-methylhydroxyamine, N,N-dimethylhydroxyamine, N,O-dimethylhydroxyamine, N-ethylhydroxyamine, N,N-diethylhydroxyamine, N,O-diethylhydroxyamine, O,N,N-trimethylhydroxyamine, N,N-dicarboxyethylhydroxyamine, and N,N-disulfoethylhydroxyamine.

[0071] Examples of salts of hydroxyamine and hydroxyamine derivatives include inorganic acid salts and organic acid salts, with inorganic acid salts formed by the bonding of non-metal atoms of Cl, S, N, or P to hydrogen atoms being preferred, and salts of any of the acids hydrochloric acid, sulfuric acid, and nitric acid being more preferred. As inorganic salts of hydroxylamine and hydroxylamine derivatives, hydroxylamine nitrate, hydroxylamine sulfate, hydroxylamine hydrochloride, hydroxylamine phosphate, N,N - diethylhydroxylamine sulfate, N,N - diethylhydroxylamine nitrate or a mixture thereof are preferred. As organic salts of hydroxylamine and hydroxylamine derivatives, for example, hydroxylammonium citrate, hydroxylammonium oxalate and hydroxylammonium fluoride can be mentioned, and hydroxylamine is preferred.

[0072] The content of the basic compound is preferably 0.01 - 30% by mass, more preferably 0.1 - 20% by mass, based on the total mass of the chemical solution.

[0073] Examples of inorganic bases include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides, and ammonia and its salts.

[0074] As the basic compound, quaternary ammonium hydroxide is preferred in terms of low metal residue after use, economy and stability of the composition, etc., TMAH or TEAH is more preferred, and TEAH is even more preferred.

[0075] (Acidic compound) The acidic compound is an acidic compound that shows acidity (pH less than 7.0) in an aqueous solution. The acidic compound is a compound different from the above various components. Examples of acidic compounds include inorganic acids, organic acids and their salts.

[0076] Examples of inorganic acids include sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, perchloric acid and their salts, sulfuric acid, hydrochloric acid or nitric acid is preferred, and nitric acid, sulfuric acid or hydrochloric acid is more preferred.

[0077] Examples of organic acids include sulfonic acids and their salts. Examples of the sulfonic acid include methanesulfonic acid (MSA), benzenesulfonic acid, p-toluenesulfonic acid (tosylic acid), and their salts.

[0078] As the acidic compound, sulfuric acid, hydrochloric acid, nitric acid, sulfonic acid, or their salts are preferable, and sulfuric acid, hydrochloric acid, methanesulfonic acid, or p-toluenesulfonic acid are more preferable.

[0079] The content of the pH adjuster is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, based on the total mass of the chemical solution. The upper limit is preferably 20.0% by mass or less, based on the total mass of the chemical solution.

[0080] (Surfactant) The chemical solution may contain a surfactant. The surfactant is a compound different from the above various components. Examples of the surfactant include compounds having a hydrophilic group and a hydrophobic group in the molecule, and specifically, anionic surfactants, cationic surfactants, and nonionic surfactants.

[0081] Examples of the hydrophobic group of the surfactant include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a group combining them. When the hydrophobic group has an aromatic hydrocarbon group, the number of carbon atoms of the aromatic hydrocarbon group is preferably 6 or more, more preferably 10 or more. The upper limit is preferably 24 or less, more preferably 20 or less. When the hydrophobic group has only an aliphatic hydrocarbon group, the number of carbon atoms of the aliphatic hydrocarbon group is preferably 8 or more, more preferably 10 or more. The upper limit is preferably 24 or less, more preferably 20 or less.

[0082] Examples of the anionic surfactant include anionic surfactants having at least one group selected from the group consisting of a sulfonic acid group, a sulfate ester group, and a phosphonic acid group in the molecule.

[0083] Examples of the anionic surfactant having a sulfonic acid group include alkyl sulfonic acid, alkyl benzene sulfonic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl ether sulfonic acid, fatty acid amide sulfonic acid, and salts thereof. Examples of the salt of the anionic surfactant include ammonium salt, sodium salt, potassium salt, and tetramethylammonium salt.

[0084] Examples of the cationic surfactant include compounds having a cationic hydrophilic group and the above hydrophobic group, and specifically include quaternary ammonium salt-based surfactants and alkyl pyridinium-based surfactants.

[0085] The content of the surfactant is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, based on the total mass of the chemical solution. From the viewpoint of suppressing foaming of the chemical solution, the upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total mass of the chemical solution.

[0086] (Other organic solvents) The chemical solution may contain other organic solvents in addition to the aprotic polar solvent. Examples of the other organic solvents include hydrophilic organic solvents, and alcohol-based solvents are preferred. The "hydrophilic organic solvent" means an organic solvent that dissolves 0.1 g or more in 100 g of water under the condition of 25°C. As the hydrophilic organic solvent, an organic solvent that can be uniformly mixed with water in any mixing ratio is preferred.

[0087] Examples of the alcohol-based solvent include alkanediol, alkoxy alcohol, saturated aliphatic monohydric alcohol, unsaturated non-aromatic monohydric alcohol, and low molecular weight alcohol containing a ring structure. Examples of the alkanediol include glycol, 2-methyl-1,3-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, and pinacol. Examples of the alkoxy alcohol include 3-methoxy-3-methyl-1-butanol, 3-methoxy-1-butanol, and 1-methoxy-2-butanol. Examples of the saturated aliphatic monohydric alcohol include methanol, ethanol, n-propyl alcohol, isopropanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 2-pentanol, t-pentyl alcohol, and 1-hexanol. Examples of the unsaturated non-aromatic monohydric alcohol include allyl alcohol, propargyl alcohol, 2-butenyl alcohol, 3-butenyl alcohol, and 4-penten-2-ol. Examples of the low molecular weight alcohol containing a ring structure include tetrahydrofurfuryl alcohol, furfuryl alcohol, and 1,3-cyclopentanediol.

[0088] The content of the other organic solvent is preferably 0.001 to 10% by mass, more preferably 0.01 to 3% by mass, based on the total mass of the chemical solution.

[0089] 〔Physical properties of the chemical solution〕 <ph> The pH of the chemical solution is preferably 7 or less, more preferably 3 or less, and even more preferably 2 or less. The lower limit is preferably 0 or more. The pH of the chemical solution is a value obtained by measurement at a liquid temperature of 25°C using a known pH meter.

[0090] <Metal content> In the chemical solution, the content (measured as ionic concentration) of metals (metal elements of Fe, Co, Na, Cu, Mg, Mn, Li, Al, Cr, Ni, Zn, Sn, and Ag) contained as impurities in the solution is preferably 5 mass ppm or less for each, and more preferably 1 mass ppm or less. In the production of state-of-the-art semiconductor elements, since it is assumed that a chemical solution of even higher purity is required, it is even more preferable that the metal content is lower than 1 mass ppm, that is, in the order of mass ppb or less, particularly preferably 100 mass ppb or less, and most preferably less than 10 mass ppb. The lower limit is preferably 0 mass ppb.

[0091] As a method for reducing the metal content, for example, at the stage of raw materials used in manufacturing the chemical solution or at the stage after manufacturing the chemical solution, purification treatments such as distillation and filtration using an ion exchange resin or a filter can be performed. Also, the filtration process described later may be used. As another method for reducing the metal content, as a container for containing raw materials or the manufactured chemical solution, a container with less elution of impurities described later can be used. Also, lining the inner wall of the pipe with a fluororesin so that metal components do not elute from the pipe during the production of the chemical solution can be mentioned.

[0092] <Coarse particles> The chemical solution may contain coarse particles, but it is preferable that the content is low. The coarse particles are preferably different from the polishing particles. Coarse particles mean particles having a diameter (particle size) of 0.03 μm or more when the shape of the particles is regarded as a sphere. As for the content of coarse particles in the chemical solution, the content of particles with a particle size of 0.1 μm or more is preferably 10,000 or less per 1 mL of the chemical solution, and more preferably 5,000 or less. The lower limit is preferably 0 or more per 1 mL of the chemical solution, and more preferably 0.01 or more. The coarse particles contained in the chemical solution are particles such as dust, dirt, organic solids, and inorganic solids contained as impurities in the raw material, and particles such as dust, dirt, organic solids, and inorganic solids brought in as contaminants during the preparation of the chemical solution, and those that finally exist as particles without dissolving in the chemical solution are applicable. The content of coarse particles present in the chemical solution can be measured in the liquid phase using a commercially available measuring device in a light scattering type in-liquid particle measuring method using a laser as a light source. Examples of the method for removing coarse particles include purification treatments such as filtering described later.

[0093] [Method for manufacturing chemical solution] As the method for manufacturing the chemical solution, for example, a known manufacturing method can be used. The method for manufacturing the chemical solution preferably has a chemical solution preparation step.

[0094] [Chemical solution preparation step] Examples of the chemical solution preparation step include a method of preparing phosphoric acid or its salt, an aprotic polar solvent, water, and a specific compound, and mixing these components to prepare the chemical solution. In the chemical solution preparation step, the order of mixing various components is not particularly limited. Either batch mixing or divided mixing of various components may be used.

[0095] [Filtration step] The method for manufacturing the chemical solution may have a filtration step of filtering the chemical solution in that foreign matters, coarse particles, etc. can be removed from the chemical solution. Examples of the filtration method include known filtration methods, and filtration using a filter is preferred.

[0096] Examples of the filter used for filtration include filters used for known filtration. Examples of the material constituting the filter include fluororesins such as PTFE (polytetrafluoroethylene), polyamide resins such as nylon, and polyolefin resins (including high density and ultra-high molecular weight) such as polyethylene and polypropylene (PP). Polyamide resin, PTFE or polypropylene (including high density polypropylene) is preferred. By using the filter composed of the above material, foreign substances with high polarity that are likely to cause defects can be more effectively removed from the chemical solution.

[0097] The pore size of the filter is preferably 0.001 to 1.0 μm, more preferably 0.02 to 0.5 μm, and even more preferably 0.01 to 0.1 μm. When the pore size of the filter is within the above range, fine foreign substances can be removed from the chemical solution while suppressing filter clogging.

[0098] The filtering can be performed one time or two or more times, and one type or two or more types of filters can be used. When performing filtering two or more times by combining the first filter and a second filter different from the first filter, each filter may be the same or different, and it is preferably different. It is preferable that at least one of the pore size and the constituent material of the first filter and the second filter is different. The pore size of the filtering after the second time is preferably the same as the pore size of the first filtering or smaller than the pore size of the first filtering. As the pore size, the nominal value of the filter manufacturer can be used.

[0099] Examples of the filter include a P-nylon filter made of polyamide (pore size 0.02 μm, critical surface tension 77 mN / m, manufactured by Nippon Paul), a PE·Clean filter made of high density polyethylene (pore size 0.02 μm, manufactured by Nippon Paul), and a PE·Clean filter made of high density polyethylene (pore size 0.01 μm, manufactured by Nippon Paul). The description in paragraphs

[0154] to

[0162] of International Publication No. 2021 / 049208 is cited, and these contents are incorporated herein.

[0100] [Electrostatic elimination process] The method for manufacturing the chemical solution may include an electrostatic elimination process for eliminating static electricity from the chemical solution. Examples of the electrostatic elimination method include known methods such as a method of bringing the material to be purified into contact with a conductive material. The contact time for bringing the material to be purified into contact with the conductive material is preferably 0.001 to 60 seconds, more preferably 0.001 to 1 second, and even more preferably 0.01 to 0.1 second. Examples of the conductive material include stainless steel, gold, platinum, diamond, and glassy carbon. Examples of the method for bringing the material to be purified into contact with the conductive material include a method of disposing a grounded mesh made of a conductive material inside a pipeline and passing the material to be purified therethrough. Examples of the electrostatic elimination process include the description in paragraph

[0120] of International Publication No. 2021 / 052186, and the contents thereof are incorporated herein.

[0101] Each step in the method for manufacturing the chemical solution is preferably carried out in a clean room. The clean room preferably satisfies the 14644-1 clean room standard. Further, it preferably satisfies any one of ISO (International Organization for Standardization) Class 1, ISO Class 2, ISO Class 3, and ISO Class 4, more preferably satisfies any one of ISO Class 1 and ISO Class 2, and even more preferably satisfies ISO Class 1.

[0102] [Container] As the container for storing the chemical solution, for example, a known container can be used. As the container, those having a high cleanliness inside the container for semiconductor applications and little elution of impurities are preferable. Examples of the container include the "Clean Bottle" series (manufactured by Asahi Kasei Chemicals Corporation) and "Pure Bottle" (manufactured by Kodama Resin Industry Co., Ltd.). From the viewpoint of preventing impurity mixing, a multilayer container having a six-layer structure made of six types of resins or a multilayer container having a seven-layer structure made of seven types of resins for the inner wall of the container is preferable. Examples of the multilayer container include the container described in JP-A-2015-123351, the contents of which are incorporated herein. Examples of the material for the inner wall of the container include at least one first resin selected from the group consisting of a polyethylene resin, a polypropylene resin, and a polyethylene-polypropylene resin, a second resin different from the first resin, and metals such as stainless steel, Hastelloy, Inconel, and Monel. Further, the inner wall of the container is preferably formed or coated using the above materials.

[0103] The second resin is preferably a fluororesin (perfluororesin). When a fluororesin is used, elution of oligomers of ethylene or propylene can be suppressed. Examples of the above container include FluoroPurePFA composite drums (manufactured by Entegris), page 4 of JP-T-3-502677, page 3 of WO 2004 / 016526 pamphlet, and pages 9 and 16 of WO 99 / 046309 pamphlet.

[0104] In addition to the above fluororesin, quartz and electrolytically polished metal materials (electrolytically polished metal materials) are also preferable as the inner wall of the container. The metal material used for the electrolytically polished metal material preferably contains at least one selected from the group consisting of chromium (Cr) and nickel (Ni), and the content of Cr and Ni is more than 25% by mass based on the total mass of the metal material. Examples of the above metal material include stainless steel and Ni-Cr alloy. Examples of the above metal material include the descriptions in paragraphs

[0075] to

[0077] of WO 2020 / 040042, the contents of which are incorporated herein.

[0105] Examples of the method for electrolytically polishing the metal material include known methods. Specifically, the methods described in paragraphs

[0011] to

[0014] of JP-A-2015-227501 and paragraphs

[0036] to

[0042] of JP-A-2008-264929 are exemplified, and the contents thereof are incorporated herein.

[0106] It is presumed that the chromium content in the passive layer on the surface of the metal material becomes higher than that in the matrix phase by electrolytic polishing. Therefore, it is presumed that since metal elements hardly flow out into the chemical solution from the inner wall coated with the electrolytically polished metal material, a chemical solution with a reduced specific metal element can be obtained.

[0107] The metal material is preferably buffed. Examples of the buffing method include known methods. The size of the abrasive grains used for the finish of buffing is preferably #400 or less in terms of the surface unevenness of the metal material being more likely to become smaller. Buffing is preferably performed before electrolytic polishing. The metal material may be treated by combining one or two or more of multiple-stage buffing, pickling, and magnetic fluid polishing performed by changing the count such as the size of the abrasive grains.

[0108] It is preferable to clean the inside of the container before filling it with the chemical solution. The liquid used for cleaning can be appropriately selected according to the application, and a liquid containing at least one of the above chemical solution or the components added to the above chemical solution is preferable.

[0109] From the viewpoint of preventing changes in the components in the chemical solution during storage, the inside of the container may be replaced with an inert gas having a purity of 99.99995 vol% or more (for example, nitrogen and argon). In particular, a gas with a low water content is preferable. Also, during transportation and storage of the container containing the chemical solution, either normal temperature or temperature control may be employed. Among these, from the viewpoint of preventing deterioration, it is preferable to control the temperature in the range of -20 to 20°C.

[0110] [Application] The use of the chemical solution is preferably for semiconductor devices, and more preferably as an etching solution. "For semiconductor devices" means being used during the manufacture of semiconductor devices. The chemical solution can also be used in the processes for manufacturing semiconductor devices. For example, it can be used for treating transition metal-containing substances, insulating films, resist films, antireflection films, etching residues, ashing residues, etc. present on the substrate. The above chemical solution may be used for treating the substrate after chemical mechanical polishing.

[0111] [Object to be treated] The chemical solution is preferably used to remove Al oxide. Al oxide is often disposed on the substrate. Note that "on the substrate" includes any of the front, back, side, and inside of the grooves of the substrate. Also, "Al oxide on the substrate" includes the case where Al oxide is directly on the surface of the substrate and the case where Al oxide is present on the substrate via other layers.

[0112] Examples of the object to be treated include objects to be treated containing Al oxide and Ga oxide. More specifically, examples include objects to be treated containing a substrate, Al oxide disposed on the substrate, and Ga oxide disposed on the substrate. Objects to be treated containing a substrate, Al oxide disposed on the substrate, Ga oxide disposed on the substrate, and metal oxide containing Hf on the substrate (hereinafter also referred to as "Hf oxide") are preferred. Examples of Hf oxide include HfO 2 and the like.

[0113] Al oxide may be an oxide containing Al (Al atoms) and may contain other metals. The content of Al atoms in the Al oxide is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, based on the total mass of the Al oxide.

[0114] Ga oxide may be an oxide containing Ga (Ga atoms) and may contain other metals. The content of Ga atoms in the Ga oxide is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, based on the total mass of the Ga oxide.

[0115] The Hf oxide may be an oxide containing Hf (Hf atoms) and may contain other metals. The content of Hf atoms in the Hf oxide is preferably 5 to 65% by mass, more preferably 15 to 55% by mass, based on the total mass of the Hf oxide.

[0116] As the substrate, a semiconductor substrate is preferred. Examples of the semiconductor substrate include a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for a FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, and a substrate for a magneto-optical disk. Examples of the material constituting the semiconductor substrate include silicon, silicon germanium, group III-V compounds such as GaAs, and combinations thereof.

[0117] Examples of the use of the object to be processed include DRAM (Dynamic Random Access Memory), FRAM (registered trademark) (Ferroelectric Random Access Memory), MRAM (Magnetoresistive Random Access Memory), PRAM (Phase change Random Access Memory), logic circuits, and processors.

[0118] As the form of the Al oxide on the substrate, for example, any of a form arranged in a film shape, a form arranged in a wiring shape, and a form arranged in a particle shape may be used. As the form of the Ga oxide on the substrate and the Hf oxide on the substrate, for example, any of a form arranged in a film shape, a form arranged in a wiring shape, and a form arranged in a particle shape may be used.

[0119] When the Al oxide is in the form of a film, the thickness of the Al oxide film is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. The lower limit is preferably 0.1 nm or more. When the Ga oxide or Hf oxide is in the form of a film, the thickness of the Ga oxide film or Hf oxide film is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. The lower limit is preferably 0.1 nm or more. The Al oxide, Ga oxide, and Hf oxide may be disposed only on the main surface on one side of the substrate, or may be disposed on the main surfaces on both sides.

[0120] In addition to the Al oxide, Ga oxide, and Hf oxide, the object to be treated may contain a layer and / or structure as desired. For example, a metal wiring, a gate electrode, a source electrode, a drain electrode, an insulating layer, a ferromagnetic layer, and / or a non-magnetic layer may be disposed on the substrate. The substrate may include an exposed integrated circuit structure. Examples of the integrated circuit structure include an interconnection mechanism such as metal wiring and a dielectric material. Examples of the metal and alloy used for the interconnection mechanism include aluminum, a copper-aluminum alloy, copper, titanium, tantalum, cobalt, silicon, titanium nitride, tantalum nitride, and tungsten. The substrate may include a layer of silicon oxide, silicon nitride, silicon carbide, and / or carbon-doped silicon oxide.

[0121] The size, thickness, shape, and layer structure of the substrate can be appropriately selected as desired.

[0122] [Method for treating substrate] The treatment method of the present invention (hereinafter, also referred to as "the present treatment method") has a step A of bringing an object to be treated containing an Al oxide and a Ga oxide into contact with the above-described chemical solution. By carrying out the present treatment method, the Al oxide is selectively removed. The object to be treated in the present treatment method is as described above.

[0123] Examples of the contacting method include, for example, a method of immersing the object to be treated in the chemical solution placed in a tank, a method of spraying the chemical solution onto the object to be treated, a method of flowing the chemical solution over the object to be treated, and a method combining them, and the method of immersing the object to be treated in the chemical solution is preferred.

[0124] Furthermore, in order to further enhance the cleaning ability of the chemical solution, a mechanical stirring method may be used. Examples of the mechanical stirring method include, for example, a method of circulating the chemical solution on the object to be treated, a method of flowing or spraying the chemical solution over the object to be treated, and a method of stirring the chemical solution with ultrasonic or megasonic waves.

[0125] The treatment time of step A can be adjusted as appropriate. The treatment time (contact time between the chemical solution and the object to be treated) is preferably 0.25 to 10 minutes, more preferably 0.5 to 2 minutes. The temperature of the chemical solution during the treatment is preferably 20 to 100°C, more preferably 40 to 80°C.

[0126] In step A, while measuring the concentration of various components such as phosphoric acid or its salts contained in the chemical solution, if necessary, a treatment of adding a solvent (preferably water) to the chemical solution may be carried out. By carrying out this treatment, the concentration of various components in the chemical solution can be stably maintained within a predetermined range.

[0127] 〔Other steps〕 This treatment method may have other steps in addition to the above step A. Examples of the other steps include, for example, formation steps of each structure such as metal wiring, gate structure, source structure, drain structure, insulating layer, ferromagnetic layer, and / or non-magnetic layer (for example, layer formation, etching, chemical mechanical polishing, and transformation), resist formation step, exposure step and removal step, heat treatment step, cleaning step, and inspection step. This processing method may be performed at any stage during the back end of the line (BEOL), middle of the line (MOL), or front end of the line (FEOL), and it is preferably performed during the front end of the line or middle of the line.

Example

[0128] The present invention will be described in more detail below based on examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed restrictively by the examples shown below.

[0129] [Preparation of Chemical Solution] The chemical solutions for the examples and comparative examples were prepared by mixing the various components and contents shown in the table. All of the various components shown in the table were those classified as semiconductor grade or high-purity grade equivalent thereto. Note that the pH of the chemical solutions in each example was 2 or less.

[0130] [Various Components] <Phosphoric Acid or Its Salt> ·Phosphoric Acid

[0131] <Aprotic Polar Solvent> ·Sulfolane ·Dimethyl Sulfoxide ·Tetraethylene Glycol Dimethyl Ether ·Diethylene Glycol Diethyl Ether ·Diethylene Glycol Butyl Methyl Ether

[0132] <Specific Compound> ·Acetic Acid ·Malonic Acid ·Succinic Acid ·Glutaric Acid ·Octanoic Acid ·2-Ethylhexanoic Acid · Polyacrylic acid (Mw 5000, polyacrylic acid 5,000, manufactured by Fujifilm Wako Pure Chemical Corporation)

[0133] <Water> · Ultrapure water

[0134] <Others> · Phosphorous acid · Hydrofluoric acid · Citric acid

[0135] [Evaluation] [Etching ability of Al oxide] On a commercially available silicon wafer (diameter: 12 inches), a substrate with an Al oxide layer formed by ALD method was prepared, and a chip cut out into a 2 cm square from the obtained substrate was used as a test piece. The thickness of the Al oxide layer was 10 nm. The obtained test piece was placed in a container filled with the chemical solutions of the examples and comparative examples and stirred at 250 rpm. The treatment temperature was the temperature shown in the table, and the treatment time was 5 seconds, 10 seconds, 30 seconds or 60 seconds. Using ellipsometry (a spectroscopic ellipsometer, Vase manufactured by J.A. Woollam Japan Co., Ltd.), the film thickness before and after treatment at each treatment time was measured to calculate the etching rate (unit: Å / min), and the average value of 5 points was adopted (measurement conditions, measurement range: 1.2 - 2.5 eV, measurement angle: 70 degrees, 75 degrees). The arithmetic mean of the etching rates at each obtained treatment time was used as the evaluation value. The etching rate of Al oxide is preferably 1.0 Å / min or more.

[0136] [Etching ability of Ga oxide] On a commercially available silicon wafer (diameter: 12 inches), a substrate with a Ga oxide layer formed by ALD method was prepared, and a chip cut out into a 2 cm square from the obtained substrate was used as a test piece. The thickness of the Ga oxide layer was 10 nm. Using the above test piece, the etching ability of Ga oxide was evaluated in the same procedure as the evaluation of the etching ability of Al oxide. The etching rate of Ga oxide is preferably 200.0 Å / min or less.

[0137] [Etching ability of hafnium oxide (HfO 2 )] On a commercially available silicon wafer (diameter: 12 inches), a substrate with a hafnium oxide (HfO 2 ) layer formed by ALD method was prepared, and a chip cut out into a 2 cm square from the obtained substrate was used as a test piece. The thickness of the hafnium oxide (HfO 2 ) layer was 10 nm. Using the above test piece, the etching ability of hafnium oxide (HfO 2 ) was evaluated in the same procedure as the evaluation of the etching ability of aluminum oxide. The etching rate of hafnium oxide (HfO 2 ) is preferably 10.0 Å / min or less.

[0138] [Etching rate ratio (selectivity) of aluminum oxide / gallium oxide] Using each obtained etching rate value, the ratio of the etching rate of aluminum oxide to the etching rate of gallium oxide (etching rate of aluminum oxide / etching rate of gallium oxide) was determined, and the etching selectivity of aluminum oxide / gallium oxide was evaluated. The above speed ratio is preferably 0.20 or more.

[0139] [Surface roughness of gallium oxide] On a commercially available silicon wafer (diameter: 12 inches), a substrate with a gallium oxide layer formed by ALD method was prepared, and a chip cut out into a 2 cm square from the obtained substrate was used as a test piece. The thickness of the gallium oxide layer was 10 nm. The obtained test piece was placed in a container filled with the chemical solutions of the examples and comparative examples and stirred at 250 rpm. The treatment temperature was the temperature shown in the table, and the treatment time was 30 seconds. When all of the gallium oxide layer on the test piece was dissolved within 30 seconds, the treatment time was set to 5 seconds or 10 seconds. The obtained test piece was sputtered with platinum at 1 nm, and the surface of the test piece was observed using SEM (field emission scanning electron microscope: S-4800, manufactured by Hitachi High-Technologies Corporation). The surface roughness of gallium oxide was evaluated according to the following evaluation criteria. A: No surface roughness B: Some surface roughness C: There were many surface irregularities

[0140] In the table, each description indicates the following. The numerical values in the column of each component indicate the content (% by mass) of each component with respect to the total mass of each chemical solution. The column of "aprotic polar solvent / phosphoric acid" indicates the mass ratio of the content of the aprotic polar solvent to the content of phosphoric acid (content of aprotic polar solvent / content of phosphoric acid).

[0141]

Table 1

[0142]

Table 2

[0143]

Table 3

[0144] From the results shown in the table, it was confirmed that the chemical solution of the present invention can obtain the effects of the present invention. When the water content is 2.0 to 30.0% by mass with respect to the total mass of the chemical solution, it was confirmed that the etching selectivity of aluminum oxide with respect to gallium oxide is more excellent (comparison of Examples 1 to 5, etc.). Also, when the water content is 2.0 to 10.0% by mass with respect to the total mass of the chemical solution, it was confirmed that the etching selectivity of aluminum oxide with respect to gallium oxide is more excellent (comparison of Examples 1 to 5, 7 to 11, and 19 to 20, etc.). When the specific compound contains at least one compound selected from the group consisting of malonic acid, poly(meth)acrylic acid, and salts thereof (preferably containing malonic acid), it was confirmed that the etching selectivity of aluminum oxide with respect to gallium oxide is more excellent (comparison of Examples 12 to 17, etc.). When the content of phosphoric acid or its salt is 3.0% by mass or less with respect to the total mass of the chemical solution, it was confirmed that the etching selectivity of aluminum oxide with respect to gallium oxide is more excellent (comparison of Examples 18 and 20, etc.). When the etching rate of gallium oxide was suppressed, it was confirmed that the surface roughness of gallium oxide could be suppressed (comparison of Examples 1 to 26, etc.).< / ph>

Claims

1. A chemical solution comprising phosphoric acid or a salt thereof, an aprotic polar solvent, water, and a compound having a carboxy group and no hydroxy group or a salt thereof, wherein the content of the phosphoric acid or a salt thereof is 5.0% by mass or less based on the total mass of the chemical solution, the content of the aprotic polar solvent is 50.0% by mass or more based on the total mass of the chemical solution, the content of the water is 2.0% by mass or more and less than 50.0% by mass based on the total mass of the chemical solution, and the chemical solution is used for removing the oxide containing Al from a workpiece containing a metal oxide containing Al and a metal oxide containing Ga.

2. A chemical solution comprising phosphoric acid or a salt thereof, an aprotic polar solvent, water, and a compound having a carboxy group and no hydroxy group or a salt thereof, wherein the content of the phosphoric acid or a salt thereof is 5.0% by mass or less based on the total mass of the chemical solution, the content of the aprotic polar solvent is 50.0% by mass or more based on the total mass of the chemical solution, the content of the water is 2.0% by mass or more and less than 50.0% by mass based on the total mass of the chemical solution, and the mass ratio of the content of the aprotic polar solvent to the content of the phosphoric acid or a salt thereof is more than 40.

3. A chemical solution comprising phosphoric acid or a salt thereof, an aprotic polar solvent, water, and a compound having a carboxy group and no hydroxy group or a salt thereof, wherein the content of the phosphoric acid or a salt thereof is 5.0% by mass or less based on the total mass of the chemical solution, the content of the aprotic polar solvent is 50.0% by mass or more based on the total mass of the chemical solution, the content of the water is 2.0% by mass or more and less than 50.0% by mass based on the total mass of the chemical solution, and the compound having a carboxy group and no hydroxy group or a salt thereof contains at least one compound selected from the group consisting of a compound represented by formula (C1) and a compound having a repeating unit represented by formula (C2). Z1-L1-(Z2)n (C1) In formula (C1), Z1 represents a hydrocarbon group. L1 represents a single bond. Z2 represents a carboxy group or a salt thereof. n represents 1. 【Chemical 1】 In formula (C2), R2 represents a hydrogen atom, a methyl group, or a carboxy group or a salt thereof. L2 represents a single bond or a divalent linking group. Z3 represents a carboxy group or a salt thereof.

4. The chemical solution according to claim 3, wherein the compound having a carboxy group and no hydroxy group or a salt thereof contains at least one compound selected from the group consisting of acetic acid, octanoic acid, 2-ethylhexanoic acid, poly(meth)acrylic acid, and salts thereof.

5. The chemical solution according to any one of claims 2 to 4, which is used for an object to be treated containing a metal oxide containing Al and a metal oxide containing Ga.

6. The chemical solution according to any one of claims 1, 3, and 4, wherein the mass ratio of the content of the aprotic polar solvent to the content of the phosphoric acid or a salt thereof is more than 40.

7. The chemical solution according to claim 1 or 2, wherein the compound having a carboxy group and no hydroxy group or a salt thereof contains at least one compound selected from the group consisting of a compound represented by formula (C1) and a compound having a repeating unit represented by formula (C2). Z １ -L １ -(Z ２ ) ｎ (C1) In formula (C1), Z １ represents a hydrocarbon group, or a carboxy group or a salt thereof. L １ represents a single bond or an (n + 1)-valent hydrocarbon group. Z ２ represents a carboxy group or a salt thereof. n represents an integer of 1 to 5. However, when L １ represents a single bond, n represents 1. [Chemical Formula 2] In formula (C2), R ２ represents a hydrogen atom, a methyl group, or a carboxy group or a salt thereof. L ２ represents a single bond or a divalent linking group. Z ３ represents a carboxy group or a salt thereof.

8. The chemical solution according to any one of claims 1, 2, and 7, wherein the compound having a carboxy group and no hydroxy group or a salt thereof contains at least one compound selected from the group consisting of acetic acid, malonic acid, succinic acid, glutaric acid, octanoic acid, 2-ethylhexanoic acid, poly(meth)acrylic acid, and salts thereof.

9. The chemical solution according to any one of claims 1 to 8, wherein the content of the phosphoric acid or a salt thereof is 3.0% by mass or less based on the total mass of the chemical solution.

10. The chemical solution according to any one of claims 1 to 9, wherein the aprotic polar solvent contains at least one solvent selected from the group consisting of sulfolane, dimethyl sulfoxide, and ether solvents.

11. The chemical solution according to any one of claims 1 to 10, wherein the aprotic polar solvent contains sulfolane.

12. The chemical solution according to any one of claims 1 to 11, wherein the mass ratio of the content of the aprotic polar solvent to the content of the phosphoric acid or a salt thereof is more than 80.

13. The chemical solution according to any one of claims 1 to 12, wherein the content of the water is 2.0 to 30.0% by mass based on the total mass of the chemical solution.

14. The chemical solution according to any one of claims 1 to 13, wherein the content of the water is 2.0 to 15.0% by mass based on the total mass of the chemical solution.

15. The chemical solution according to any one of claims 1 to 14, wherein the content of the water is 2.0 to 10.0% by mass based on the total mass of the chemical solution.

16. The chemical solution according to any one of claims 1 to 15, substantially free of fluoride.

17. The chemical solution according to any one of claims 1 to 16, substantially free of hydrogen peroxide.

18. The chemical solution according to any one of claims 1 to 17, substantially free of abrasive particles.

19. The chemical solution according to any one of claims 1 to 18, having a pH of 2 or less.

20. The chemical solution according to any one of claims 1 to 19, used as an etching solution.

21. A processing method, comprising a step of bringing an object to be processed, which contains a metal oxide containing Al and a metal oxide containing Ga, into contact with the chemical solution according to any one of claims 1 to 20.

22. The processing method according to claim 21, wherein the temperature of the chemical solution is 40 to 80°C.

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