Chemical solution, chemical solution container

Abstract

A chemical solution and a chemical solution container that are unlikely to cause metal residue defects when brought into contact with a silicon substrate. [Solution] A chemical solution containing an organic solvent and a metal component, wherein the metal component contains silver ions, and the content of the silver ions is 0.0010 to 1.0 ppt by mass relative to the total mass of the chemical solution.

Description

[Technical Field]

[0001] This invention relates to a drug solution and a drug solution container. [Background technology]

[0002] In the manufacturing of semiconductor devices by wiring formation processes including photolithography, chemical solutions containing water and / or organic solvents are used as pre-wetting solutions, resist solutions (compositions for forming resist films), developers, rinse solutions, stripping solutions, chemical mechanical polishing (CMP) slurries, and post-CMP cleaning solutions, or as diluents thereof. In recent years, advances in photolithography technology have led to the miniaturization of patterns. Methods for miniaturizing patterns include pattern formation using exposure light sources such as ultraviolet light, KrF excimer lasers, ArF excimer lasers, and EUV (extreme ultraviolet light). As the patterns formed become finer, the chemicals used in this process require even greater defect suppression capabilities.

[0003] As a chemical solution used in conventional pattern formation, Patent Document 1 discloses "a method for producing an organic treatment solution for patterning chemically amplified resist films that can reduce particle generation in pattern formation technology (paragraph

[0010] )." [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2015-084122 [Overview of the project] [Problems that the invention aims to solve]

[0005] On the other hand, in recent years, there has been a demand for chemical solutions that are less likely to cause metal residue defects on the silicon substrate when the silicon substrate is brought into contact with the chemical solution. The present invention aims to provide a chemical solution that is less likely to cause metal residue defects when in contact with a silicon substrate. Furthermore, the present invention also aims to provide a drug solution container. [Means for solving the problem]

[0006] As a result of diligent research to solve the above problems, the inventors of this invention have found that the above problems can be solved by the following configuration.

[0007] (1) A chemical solution containing an organic solvent and a metal component, The metal component contains silver ions, A drug solution containing silver ions in an amount of 0.0010 to 1.0 mass ppt relative to the total mass of the drug solution. (2) The drug solution described in (1), wherein the content of the metal component is 10.0 to 500 ppt by mass relative to the total mass of the drug solution. (3) The metal component contains silver oxide particles, The drug solution described in (2), wherein the mass ratio of the silver oxide particle content to the silver ion content is 0.00000010 to 0.1. (4) The chemical solution described in (3), wherein the content of silver oxide particles is 0.00010 to 5.0% by mass relative to the content of silver in the metal component. (5) The metal component contains titanium oxide particles and titanium ions, The chemical solution described in (3) or (4), wherein the mass ratio of titanium dioxide particle content to titanium ion content, where 2 and 1, satisfies the relationship given by the following formula (A). Formula (A) Mass ratio 2>mass ratio 1 (6) The ratio of titanium oxide particles to silver oxide particles is 10 2 ~10 10 The drug solution described in (5). (7) The number of titanium dioxide particles is 10 2 ~10 10 The drug solution described in (5) or (6), which is one in number. (8) The content of titanium oxide particles is 5% by mass or more and less than 98% by mass with respect to the content of titanium component in the metal component, and the chemical solution according to any one of (5) to (7). (9) Among the titanium oxide particles, the proportion of particles having a particle size of 0.5 to 17 nm is 40% by mass or more and less than 99% by mass, and the chemical solution according to any one of (5) to (8). (10) The metal component contains copper oxide particles and copper ions. The chemical solution according to any one of (3) to (9), wherein the mass ratio 3 of the content of copper oxide particles to the content of copper ions and the mass ratio 1 satisfy the relationship of the following formula (B). Formula (B) Mass ratio 3 > Mass ratio 1 (11) The metal component contains iron oxide particles and iron ions. The chemical solution according to any one of (3) to (9), wherein the mass ratio 4 of the content of iron oxide particles to the content of iron ions and the mass ratio 1 satisfy the relationship of the following formula (C). Formula (C) Mass ratio 4 > Mass ratio 1 (12) The metal component contains platinum ions. The chemical solution according to any one of (1) to (11), wherein the content of platinum ions is 0.000010 to 1.0 mass ppt with respect to the total mass of the chemical solution. (13) The metal component contains gold ions. The chemical solution according to any one of (1) to (12), wherein the content of gold ions is 0.00010 to 1.0 mass ppt with respect to the total mass of the chemical solution. (14) Further, it contains organic impurities. The chemical solution according to any one of (1) to (13), wherein the content of organic impurities is 1000 to 100000 mass ppt with respect to the total mass of the chemical solution. (15) The chemical solution according to any one of (1) to (14), wherein the content of water with respect to the total mass of the chemical solution is 500 mass ppb or less. (16) The chemical solution according to any one of (1) to (15), wherein the organic solvent contains one or more selected from the group consisting of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, cyclohexanone, ethyl lactate, propylene carbonate, isopropanol, 4-methyl-2-pentanol, butyl acetate, propylene glycol monoethyl ether, propylene glycol monopropyl ether, methyl methoxypropionate, cyclopentanone, γ-butyrolactone, diisoamyl ether, isoamyl acetate, dimethyl sulfoxide, N-methylpyrrolidone, diethylene glycol, ethylene glycol, dipropylene glycol, propylene glycol, ethylene carbonate, sulfolane, cycloheptanone, 2-heptanone, butyl butyrate, isobutyl isobutyrate, isoamyl ether, and undecane. (17) A chemical solution container containing a container and the chemical solution according to any one of (1) to (16) contained in the container. [Advantages of the Invention]

[0008] According to the present invention, it is possible to provide a chemical solution that is less likely to cause metal residue defects when brought into contact with a silicon substrate. Also, according to the present invention, it is possible to provide a chemical solution container. [Embodiments for Carrying Out the Invention]

[0009] Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. In this specification, 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. Also, in the present invention, "ppm" means "parts-per-million (10 -6 )", "ppb" means "parts-per-billion (10 -9 )", and "ppt" means "parts-per-trillion (10 -12) means "ppq" is "parts-per-quadrillion (10 -15 It means ")". Furthermore, in the notation of groups (atomic groups) in this invention, notations that do not specify substitution or unsubstituted include both unsubstituted and substituted groups, to the extent that they do not impair the effects of the present invention. For example, "hydrocarbon group" includes not only unsubstituted hydrocarbon groups but also substituted hydrocarbon groups. This also applies to each compound. Furthermore, in this invention, "radiation" means, for example, far ultraviolet light, extreme ultraviolet light (EUV), X-rays, or electron beams. Also, in this invention, "light" means active light or radiation. In this invention, unless otherwise specified, "exposure" includes not only exposure with far ultraviolet light, X-rays, or EUV, but also drawing with particle beams such as electron beams or ion beams.

[0010] The mechanism by which the above problems are solved by the drug solution of the present invention is not necessarily clear, but the inventors speculate on the mechanism as follows. Note that the following mechanism is speculative, and even if the effects of the present invention are obtained by a different mechanism, it is still within the scope of the present invention. The inventors have found that when a chemical solution contains silver ions, the likelihood of metal residue defects (residues derived from metal components) occurring on a silicon substrate differs depending on the amount of silver ions. More specifically, when the amount of silver ions exceeds a predetermined value, a large number of silver ions are present, and it is thought that these silver ions are reduced on the silicon substrate, causing a large amount of silver particles to adhere to the silicon substrate and resulting in metal residue defects. On the other hand, when the amount of silver ions is below a predetermined value, the frequency of collisions with organic matter or other ions decreases, and as a result, the possibility of reaction with the silicon substrate increases, resulting in metal residue defects. In contrast, when the amount of silver ions is within a predetermined range, the frequency of collisions with organic matter or other ions increases, resulting in the formation of various composites, which reduces the amount of silver ions used in the reduction reaction on the silicon substrate, making it less likely for metal residue defects to form.

[0011] The present invention provides a chemical solution containing an organic solvent and a metal component, wherein the metal component contains silver ions, and the silver ion content is 0.0010 to 1.0 ppt by mass relative to the total mass of the chemical solution. The components contained in the drug solution of the present invention will be described in detail below.

[0012] <Organic solvents> The chemical solution of the present invention (hereinafter also simply referred to as "chemical solution") contains an organic solvent. In this specification, an organic solvent refers to a liquid organic compound contained in a concentration exceeding 10,000 ppm by mass per component relative to the total mass of the above-mentioned chemical solution. In other words, in this specification, a liquid organic compound contained in a concentration exceeding 10,000 ppm by mass relative to the total mass of the above-mentioned chemical solution is considered an organic solvent. Furthermore, in this specification, "liquid" means that it is a liquid at 25°C and atmospheric pressure.

[0013] The content of organic solvent in the chemical solution is not particularly limited, but it is preferably 98.0% by mass or more, more preferably more than 99.0% by mass, even more preferably 99.90% by mass or more, and particularly preferably more than 99.95% by mass, relative to the total mass of the chemical solution. The upper limit is less than 100% by mass. Organic solvents may be used individually or in combination of two or more. When using two or more organic solvents, it is preferable that their total content be within the above range.

[0014] The type of organic solvent is not particularly limited, and known organic solvents can be used. Examples of organic solvents include alkylene glycol monoalkyl ether carboxylates, alkylene glycol monoalkyl ethers, alkyl lactate esters, alkyl alkoxypropionates, cyclic lactones (preferably with 4 to 10 carbon atoms), monoketone compounds which may have a ring (preferably with 4 to 10 carbon atoms), alkylene carbonates, alkyl alkoxyacetates, alkyl pyruvates, dialkyl sulfoxides, cyclic sulfones, dialkyl ethers, monohydric alcohols, glycols, alkyl acetate esters, and N-alkylpyrrolidones.

[0015] The organic solvent is preferably one or more selected from the group consisting of, for example, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone (CHN), ethyl lactate (EL), propylene carbonate (PC), isopropanol (IPA), 4-methyl-2-pentanol (MIBC), butyl acetate (nBA), propylene glycol monoethyl ether, propylene glycol monopropyl ether, methyl methoxypropionate, cyclopentanone, γ-butyrolactone, diisoamyl ether, isoamyl acetate, dimethyl sulfoxide, N-methylpyrrolidone, diethylene glycol, ethylene glycol, dipropylene glycol, propylene glycol, ethylene carbonate, sulforane, cycloheptanone, 2-heptanone, butyl butyrate, isobutyl isobutyrate, isoamyl ether, and undecane. Examples of using two or more organic solvents include the combined use of PGMEA and PGME, and the combined use of PGMEA and PC. The type and content of organic solvents in the chemical solution can be measured using a gas chromatograph-mass spectrometer.

[0016] <Metal components> The chemical solution contains metallic components. Metallic components consist of metal-containing particles and metal ions. For example, when referring to the content of metallic components, it indicates the total content of metal-containing particles and metal ions. Metal-containing particles are those that contain metal atoms, such as metal oxide particles, metal nitride particles, and metal particles. Note that metal particles refer to particles composed solely of metal.

[0017] The metal component contained in the chemical solution is silver ions. The silver ion content is 0.0010 to 1.0 ppt by mass relative to the total mass of the chemical solution. A content of 0.0020 to 0.90 ppt by mass is preferred, 0.05 to 0.90 ppt by mass is more preferred, and 0.10 to 0.90 ppt by mass is even more preferred, as it is less likely to cause metal residue defects on the silicon substrate.

[0018] The metal component contained in the chemical solution may also contain silver oxide particles. When silver oxide particles are contained in the chemical solution, the mass ratio of the silver oxide particle content to the silver ion content (silver oxide particle content / silver ion content) is not particularly limited, and is often between 0.000000010 and 1.5. In particular, a mass ratio of 1 of 0.00000010 to 0.1 is preferred, 0.000001 to 0.01 is more preferred, and 0.00001 to 0.005 is even more preferred, as it is less likely to cause metal residue defects or composite residue defects (described later) on the silicon substrate or silicon oxide film.

[0019] Furthermore, the content of silver oxide particles is not particularly limited, and is often 0.00001 to 10% by mass relative to the silver content in the metal component. In particular, for the effects of the present invention to be superior, the content of silver oxide particles is preferably 0.00010 to 5.0% by mass, and more preferably 0.010 to 1.0% by mass, relative to the silver content in the metal component. The silver component refers to a component containing silver atoms, and is composed of silver-containing particles and silver ions. For example, when referring to the silver component content, it indicates the total content of silver-containing particles and silver ions. Silver-containing particles are those that contain silver atoms, such as silver oxide particles, silver nitride particles, and silver particles. Note that "silver particles" refers to particles made of metallic silver.

[0020] The metal component contained in the chemical solution may contain components other than the silver component. The metal component contained in the chemical solution may contain a titanium component. The titanium component is a component containing titanium atoms, and is composed of titanium-containing particles and titanium ions. For example, when referring to the content of the titanium component, it indicates the total content of titanium-containing particles and titanium ions. The titanium-containing particles only need to contain titanium atoms, and examples thereof include titanium oxide particles, titanium nitride particles, and titanium particles. Note that the titanium particles mean particles made of metallic titanium.

[0021] The metal component contained in the chemical solution may contain titanium oxide particles and titanium ions. The mass ratio 2 (content of titanium oxide particles / content of titanium ions) of the content of titanium oxide particles to the content of titanium ions is not particularly limited, but it is preferable to satisfy the relationship between the above-mentioned mass ratio 1 and the following formula (A). Formula (A) Mass ratio 2 > Mass ratio 1

[0022] The ratio of the content of titanium oxide particles to the content of silver oxide particles (content of titanium oxide particles / content of silver oxide particles) is not particularly limited, and is often 10 1 ~10 10 In many cases. Among them, in terms of being less likely to generate metal residue defects or composite residue defects described later on the silicon substrate or the silicon oxide film, the above ratio is 10 2 ~10 10 is preferable, and 10 3 ~10 10 is more preferable.

[0023] The number of titanium oxide particles is not particularly limited, and is often 10 0 ~10 11 In many cases. Among them, in terms of being less likely to generate metal residue defects or composite residue defects described later on the silicon substrate or the silicon oxide film, the number of titanium oxide particles is 10 2 ~10 10 is preferable, and 10 3 ~10 10 is more preferable.

[0024] The titanium oxide particle content is not particularly limited, and is often 1 to 99% by mass relative to the titanium content in the metal component. In particular, the titanium oxide particle content is preferably 5% by mass or more and less than 98% by mass, and more preferably 10 to 90% by mass, relative to the titanium content in the metal component, as this makes it less likely for metal residue defects or composite residue defects (described later) to occur on the silicon substrate or silicon oxide film. The proportion of titanium oxide particles with a particle size of 0.5 to 17 nm is not particularly limited, and is often 30 to 99% by mass. In particular, the proportion of titanium oxide particles with a particle size of 0.5 to 17 nm is preferably 40% by mass or more and less than 99% by mass, and more preferably 70 to 98% by mass, in that metal residue defects or composite residue defects described later are less likely to occur on the silicon substrate or silicon oxide film.

[0025] The metal component contained in the chemical solution may include platinum ions. The platinum ion content is not particularly limited, and is often 0.000001 to 1.5 ppt by mass relative to the total mass of the chemical solution. In particular, the platinum ion content is preferably 0.000010 to 1.0 ppt by mass, more preferably 0.00010 to 0.50 ppt by mass, and even more preferably 0.001% by mass or more and less than 0.20 ppt by mass, relative to the total mass of the chemical solution, as this makes it less likely for metal residue defects or composite residue defects (described later) to occur on the silicon substrate. The metal components contained in the chemical solution may include gold ions. The gold ion content is not particularly limited, and is often 0.000001 to 1.5 ppt by mass relative to the total mass of the chemical solution. In particular, the gold ion content is preferably 0.000010 to 1.0 ppt by mass, more preferably 0.00010 to 1.0 ppt by mass, and even more preferably 0.001% by mass or more and less than 0.10 ppt by mass, relative to the total mass of the chemical solution, as this makes it less likely for metal residue defects or composite residue defects (described later) to occur on the silicon substrate.

[0026] The metal components contained in the chemical solution may also contain other metal atom components besides those mentioned above. Other metal atoms include, for example, Na (sodium), K (potassium), Ca (calcium), Fe (iron), Cu (copper), Mg (magnesium), Mn (manganese), Li (lithium), Al (aluminum), Cr (chromium), Ni (nickel), and Zn (zirconium).

[0027] The metal components contained in the chemical solution may include copper oxide particles and copper ions. The mass ratio of copper oxide particles to copper ions (copper oxide particle content / copper ion content) is not particularly limited, but it is preferable that the above-mentioned mass ratio of 1 satisfies the relationship shown in equation (B) below. Formula (B) Mass ratio 3>mass ratio 1 The metal components contained in the chemical solution may include iron oxide particles and iron ions. The mass ratio of iron oxide particles to iron ions (iron oxide particle content / iron ion content) is not particularly limited, but it is preferable that the above-mentioned mass ratio of 1 satisfies the relationship shown in equation (C) below. Formula (C) Mass ratio 4>mass ratio 1

[0028] The metal component may be a metal component that is inevitably present in each component (raw material) contained in the chemical solution, or a metal component that is inevitably present during the manufacture, storage, and / or transport of the chemical solution, or it may be added intentionally.

[0029] The content of metal components is not particularly limited, but in order to reduce the likelihood of metal residue defects or composite residue defects (described later) occurring on the silicon substrate or silicon oxide film, a content of 1 to 500,000 ppts by mass is preferred, and 5 to 1,000 ppts by mass is more preferred, relative to the total mass of the chemical solution.

[0030] Furthermore, the types and amounts of metal ions and metal-containing particles in the chemical solution can be measured using the SP-ICP-MS method (Single Nano Particle Inductively Coupled Plasma Mass Spectrometry). Here, the SP-ICP-MS method uses the same equipment as the standard ICP-MS (inductively coupled plasma mass spectrometry) method, differing only in its data analysis. Data analysis using the SP-ICP-MS method can be performed using commercially available software. In the ICP-MS method, the content of the target metal component is measured regardless of its form of existence. Therefore, the total mass of the metal-containing particles and metal ions is quantified as the content of the metal component.

[0031] On the other hand, the SP-ICP-MS method can measure the content of metal-containing particles. Therefore, by subtracting the content of metal-containing particles from the content of metal components in the sample, the content of metal ions in the sample can be calculated. Examples of SP-ICP-MS instruments include the Agilent 8800 Triple Quadrupole ICP-MS (inductively coupled plasma mass spectrometry, for semiconductor analysis, option #200) manufactured by Agilent Technologies, which can be used for measurement by the method described in the examples. Other instruments that can be used include the PerkinElmer NexION350S and the Agilent 8900 manufactured by Agilent Technologies.

[0032] Since metal-containing particles smaller than 10 nm cannot be measured by SP-ICP-MS, the method described in paragraphs 0015 to 0067 of Japanese Patent Publication No. 2009-188333 (hereinafter also referred to as the "identification method") is used. Here, the number of 0.5-10 nm particles remaining on the substrate is counted using a specific method, and the converted value from SNP-ICP-MS for 20 nm particles is used for this count. Since the converted value differs for each metal, this conversion is performed separately for each metal. The specific conversion method is as follows: For example, if the number of 20 nm titanium oxide particles in the chemical solution is 10 as determined by SNP-ICP-MS, and the number of 20 nm titanium oxide particles remaining on the substrate as calculated by the specific method is 1, the conversion value will be 10. In other words, if the number of 1 nm titanium oxide particles confirmed by the specific method is 100, then based on 10 times the conversion value, the number in the chemical solution will be calculated as 1000 (100 x 10). In this invention, the number of particles smaller than 10 nm is estimated using this conversion method, regardless of the metal.

[0033] <Organic impurities> The chemical solution may contain organic impurities. While there are no particular restrictions on the content of organic impurities in the chemical solution, a content of 1,000 to 100,000 ppt by mass is preferred, as this is less likely to cause stain-like residue defects on the silicon substrate, as described later. Furthermore, an organic impurity refers to an organic compound different from the organic solvent, contained in an amount of 10,000 ppm by mass or less relative to the total mass of the organic solvent. In other words, in this specification, an organic compound contained in an amount of 10,000 ppm by mass or less relative to the total mass of the organic solvent is considered an organic impurity and not an organic solvent. Organic impurities are often introduced into or added to a chemical solution during the process of purifying the substance to be purified to obtain the chemical solution. Examples of such organic impurities include plasticizers, antioxidants, and compounds derived from them (typically decomposition products).

[0034] <Water> The chemical solution may contain water. Water is not included in the above-mentioned organic impurities. There are no particular restrictions on the type of water used; for example, distilled water, deionized water, and pure water can be used. Water may be added to the chemical solution, or it may be unintentionally mixed into the chemical solution during the manufacturing process. Examples of unintentional mixing during the manufacturing process include, but are not limited to, cases where water is contained in the raw materials used in the manufacture of the chemical solution (e.g., organic solvents), or where it is mixed during the manufacturing process (e.g., contamination).

[0035] The water content in the drug solution is not particularly limited, but it is preferably 2.0% by mass or less, and more preferably 500 ppb by mass or less, relative to the total mass of the drug solution. The lower limit is not particularly limited, but 0% by mass is an example. The water content in the drug solution refers to the water content measured using an apparatus that uses the Karl Fischer moisture content method as its measurement principle.

[0036] <Uses of the chemical solution> The chemical solution of the present invention is preferably used in the manufacture of semiconductor devices. In particular, it is preferable to use the chemical solution of the present invention to manufacture semiconductor chips. Specifically, in semiconductor device manufacturing processes that include lithography, etching, ion implantation, and stripping processes, it is used to treat organic matter after the completion of each process or before moving to the next process, and is preferably used as a pre-wetting solution, developer, rinse solution, and polishing solution. In addition, the chemical solution may also be used as a diluent (in other words, a solvent) for the resin contained in the resist film forming composition.

[0037] Furthermore, the above chemical solution can be used for purposes other than the manufacture of semiconductor devices, and can also be used as a developer and rinse solution for polyimides, sensor resists, and lens resists. Furthermore, the above-mentioned chemical solution can also be used as a solvent for medical or cleaning purposes. For example, it can be suitably used for cleaning pipes, containers, and substrates (e.g., wafers and glass). For the cleaning purposes described above, it is also preferable to use it as a cleaning solution (pipe cleaning solution and container cleaning solution, etc.) to clean pipes and containers that come into contact with the pre-wetting solution or other liquids mentioned above.

[0038] In particular, the chemical solution is suitably used in pre-wetting solutions, developers, rinse solutions, polishing solutions, and resist film forming compositions. It exhibits superior effects when applied to pre-wetting solutions, developers, and rinse solutions. Especially when applied to pre-wetting solutions, developers, and rinse solutions using EUV as the exposure light source, it exhibits superior effects. Furthermore, it exhibits superior effects when applied to pipe cleaning solutions used in the piping for transporting these solutions.

[0039] <Method for manufacturing the drug solution> The method for producing the above-mentioned chemical solution is not particularly limited, and known production methods can be used. In particular, in order to obtain a chemical solution that exhibits better effects of the present invention, it is preferable that the method for producing the chemical solution includes a filtration step in which the substance to be purified containing an organic solvent is filtered using a filter to obtain the chemical solution.

[0040] The material to be purified used in the filtration process may be procured by purchase or obtained by reacting raw materials. Preferably, the material to be purified has a low impurity content. Examples of commercially available products of this type include those called "high-purity grade products."

[0041] The method for reacting raw materials to obtain a product to be purified (typically a product containing an organic solvent) is not particularly limited, and known methods can be used. For example, one method is to react one or more raw materials in the presence of a catalyst to obtain an organic solvent. More specifically, examples include: a method of obtaining butyl acetate by reacting acetic acid and n-butanol in the presence of sulfuric acid; a method of obtaining 1-hexanol by reacting ethylene, oxygen, and water in the presence of Al(C2H5)3; a method of obtaining 4-methyl-2-pentanol by reacting cis-4-methyl-2-pentene in the presence of Ipc2BH (Diisopinocampheylborane); a method of obtaining PGMEA (propylene glycol 1-monomethyl ether 2-acetate) by reacting propylene oxide, methanol, and acetic acid in the presence of sulfuric acid; a method of obtaining IPA (isopropyl alcohol) by reacting acetone and hydrogen in the presence of copper oxide, zinc oxide, and aluminum oxide; a method of obtaining ethyl lactate by reacting lactic acid and ethanol; and so on.

[0042] (Filtration process) The present invention's method for producing a pharmaceutical solution preferably includes a filtration step to obtain a pharmaceutical solution by filtering the substance to be purified using a filter. While there are no particular limitations on the method of filtering the substance to be purified using a filter, it is preferable to pass the substance to be purified through a filter unit having a housing and a filter cartridge housed in the housing, under or without pressure.

[0043] • Filter pore size There are no particular restrictions on the pore size of the filter, and filters with pore sizes commonly used for filtering materials to be purified can be used. In particular, a pore size of 200 nm or less is preferred, 20 nm or less is more preferred, 10 nm or less is even more preferred, and 5 nm or less is especially preferred, as it allows for easy control of the number of particles (metal particles, etc.) contained in the chemical solution within a desired range. There are no particular restrictions on the lower limit, but generally, 1 nm or more is preferred from the viewpoint of productivity. In this specification, the pore size of the filter refers to the pore size determined by the bubble point of isopropanol (IPA).

[0044] A filter with a pore size of 5.0 nm or less is preferable because it allows for easier control of the number of particles contained in the chemical solution. Hereinafter, filters with a pore size of 5.0 nm or less will also be referred to as "micropore filters." Micropore filters may be used alone or in combination with filters of other pore sizes. In particular, from the viewpoint of superior productivity, it is preferable to use them with filters that have larger pore sizes. That is, when using two or more filters, it is preferable that at least one filter has a pore size of 5.0 nm or less. In this case, if the material to be purified is filtered beforehand using a filter with a larger pore size and then passed through the micropore filter, clogging of the micropore filter can be prevented. In other words, when using one filter, the pore size is preferably 5.0 nm or less, and when using two or more filters, the pore size of the filter with the smallest pore size is preferably 5.0 nm or less.

[0045] There are no particular limitations on the configuration in which two or more filters with different pore sizes are used sequentially, but one method is to arrange the filter units described above in order along the pipeline through which the substance to be purified is transported. In this case, if the flow rate of the substance to be purified per unit time is to be kept constant throughout the pipeline, filters with smaller pore sizes may experience greater pressure compared to filters with larger pore sizes. In this case, it is preferable to place pressure regulating valves and dampers between the filters to keep the pressure on the filters with smaller pore sizes constant, or to arrange filter units containing identical filters in parallel along the pipeline to increase the filtration area. In this way, the number of particles in the chemical solution can be controlled more stably.

[0046] • Filter materials The material of the filter is not particularly limited, and any known material can be used as the filter material. Specifically, if it is a resin, examples include polyamides such as nylon (e.g., 6-nylon and 6,6-nylon); polyolefins such as polyethylene and polypropylene; polystyrene; polyimide; polyamide-imide; poly(meth)acrylate; polyfluorocarbons such as polytetrafluoroethylene, perfluoroalkoxyalkane, perfluoroethylenepropene copolymer, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride; polyvinyl alcohol; polyester; cellulose; cellulose acetate, etc. In particular, at least one polymer selected from the group consisting of nylon (6,6-nylon is preferred), polyolefin (polyethylene is preferred), poly(meth)acrylate, and polyfluorocarbon (polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkane (PFA) are preferred) is preferred because it has superior solvent resistance and the resulting chemical solution has superior defect suppression performance. These polymers can be used individually or in combination of two or more. In addition to resin, diatomaceous earth and glass may also be used. Alternatively, polymers obtained by graft copolymerizing polyolefins (such as UPE (ultra-high molecular weight polyethylene) described later) with polyamides (for example, nylon-6 or nylon-6,6, etc.) (such as nylon-grafted UPE) may also be used as filter materials.

[0047] Furthermore, the filter may be a surface-treated filter. The surface treatment method is not particularly limited, and known methods can be used. Examples of surface treatment methods include chemical modification, plasma treatment, hydrophobic treatment, coating, gas treatment, and sintering.

[0048] Plasma treatment is preferred because it makes the filter surface hydrophilic. There are no particular limitations on the water contact angle on the plasma-treated and hydrophilic filter surface, but the static contact angle at 25°C measured with a contact angle meter is preferably 60° or less, more preferably 50° or less, and even more preferably 30° or less.

[0049] As for the chemical modification treatment, a method of introducing ion exchange groups into the filter is preferred. In other words, a filter having ion exchange groups is preferred as the filter. Examples of ion exchange groups include cation exchange groups and anion exchange groups. Examples of cation exchange groups include sulfonic acid groups, carboxyl groups, and phosphate groups, while examples of anion exchange groups include quaternary ammonium groups. There are no particular limitations on the method of introducing ion exchange groups into the filter, but a typical method involves reacting a compound containing ion exchange groups and polymerizable groups with the filter to graft them.

[0050] There are no particular restrictions on the method of introducing ion exchange groups, but the filter is irradiated with ionizing radiation (alpha rays, beta rays, gamma rays, X-rays, and electron beams, etc.) to generate active parts (radicals). After irradiation, the filter is immersed in a monomer-containing solution to allow the monomer to graft polymerize onto the filter. As a result, the polymer obtained by the polymerization of this monomer is grafted onto the filter. This generated polymer can then be contacted with a compound containing anion exchange groups or cation exchange groups to introduce ion exchange groups into the polymer.

[0051] Furthermore, the filter may also be constructed by combining a woven or nonwoven fabric in which ion exchange groups have been formed by radiation graft polymerization with a conventional glass wool, woven fabric, or nonwoven fabric filter material.

[0052] Using a filter with ion exchange groups makes it easier to control the content of metal-containing particles and metal ions in the chemical solution within a desired range. The material constituting the filter with ion exchange groups is not particularly limited, but examples include polyfluorocarbons and materials in which ion exchange groups have been introduced into polyolefins, with materials in which ion exchange groups have been introduced into polyfluorocarbons being more preferred. The pore size of the filter having ion exchange groups is not particularly limited, but is preferably 1 to 30 nm, and more preferably 5 to 20 nm. The filter having ion exchange groups may also serve as the filter having the smallest pore size as described above, or it may be used separately from the filter having the smallest pore size. In particular, in order to obtain a chemical solution that exhibits the effects of the present invention more effectively, the filtration step is preferably a configuration that uses a filter having ion exchange groups and a filter without ion exchange groups that has the smallest pore size. While there are no particular limitations on the material of the filter having the minimum pore size as described above, from the viewpoint of solvent resistance and other factors, at least one selected from the group consisting of polyfluorocarbons and polyolefins is generally preferred, and polyolefins are more preferred.

[0053] Therefore, two or more filters made of different materials may be used as filters in the filtration process. For example, two or more filters selected from the group consisting of polyolefins, polyfluorocarbons, polyamides, and materials to which ion exchange groups have been introduced may be used.

[0054] • Filter pore structure The pore structure of the filter is not particularly limited and can be appropriately selected depending on the components in the product to be purified. In this specification, the pore structure of the filter refers to the pore size distribution, the positional distribution of pores in the filter, and the shape of the pores, etc., and is typically controllable by the filter manufacturing method. For example, porous films can be obtained by sintering powders such as resin, while fibrous films can be obtained by methods such as electrospinning, electroblowing, and meltblowing. Each of these has a different pore structure.

[0055] A "porous membrane" refers to a membrane that retains components in a material being purified, such as gels, particles, colloids, cells, and polyoligomers, but allows components substantially smaller than the pores to pass through. The retention of components in the material being purified by a porous membrane may depend on operating conditions, such as face velocity, use of surfactants, pH, and combinations thereof, and may also depend on the pore size and structure of the porous membrane, as well as the size and structure (hard particles or gel, etc.) of the particles to be removed.

[0056] When the material to be purified contains negatively charged particles, a polyamide filter acts as a non-sieve membrane to remove such particles. Typical non-sieve membranes include, but are not limited to, nylon membranes such as nylon-6 and nylon-6,6 membranes. Furthermore, the term "non-sieve" retention mechanism used herein refers to retention resulting from the pressure drop of the filter or from mechanisms such as interference, diffusion, and adsorption, which are not related to the pore size.

[0057] Non-sieve retention includes retention mechanisms such as interference, diffusion, and adsorption that remove target particles from the purified material, regardless of the filter's pressure drop or pore size. Adsorption of particles to the filter surface can be mediated, for example, by intermolecular van der Waals forces and electrostatic forces. Interference occurs when particles moving through a non-sieve film layer with a meandering path cannot change direction quickly enough to avoid contact with the non-sieve film. Particle transport by diffusion arises mainly from the random motion or Brownian motion of small particles, creating a certain probability of collision between particles and the filter material. Non-sieve retention mechanisms can be active when there is no repulsive force between the particles and the filter.

[0058] UPE filters are typically sieve membranes. A sieve membrane is a membrane that primarily captures particles via a sieve-holding mechanism, or a membrane optimized for capturing particles via a sieve-holding mechanism. Typical examples of sieving membranes include, but are not limited to, polytetrafluoroethylene (PTFE) membranes and UPE membranes. The "sieve retention mechanism" refers to the retention of particles that are to be removed because their size exceeds the pore diameter of the porous membrane. Sieve retention can be improved by forming a filter cake (an aggregation of particles to be removed on the membrane surface). The filter cake effectively functions as a secondary filter.

[0059] The material of the fiber film is not particularly limited as long as it is a polymer capable of forming a fiber film. Examples of polymers include polyamides. Examples of polyamides include nylon 6 and nylon 6,6. The polymer forming the fiber film may also be poly(ethersulfone). When the fiber film is on the primary side of the porous film, it is preferable that the surface energy of the fiber film is higher than that of the polymer material of the porous film on the secondary side. An example of such a combination is when the material of the fiber film is nylon and the porous film is polyethylene (UPE).

[0060] The method for manufacturing the fiber film is not particularly limited, and known methods can be used. Examples of methods for manufacturing the fiber film include electrospinning, electroblowing, and meltblowing.

[0061] The pore structure of the porous membrane (for example, porous membranes containing UPE and PTFE, etc.) is not particularly limited, but examples of pore shapes include lace-like, string-like, and node-like structures. The distribution of pore size and its position within a porous membrane is not particularly limited. The size distribution may be smaller and the distribution within the membrane may be symmetrical. Alternatively, the size distribution may be larger and the distribution within the membrane may be asymmetrical (the above membrane is also called an "asymmetric porous membrane"). In an asymmetric porous membrane, the pore size changes within the membrane, and typically, the pore diameter increases from one surface of the membrane to the other. In this case, the surface with more pores of larger diameter is called the "open side," and the surface with more pores of smaller diameter is called the "tight side." Furthermore, an example of an asymmetric porous membrane is a membrane in which the size of the pores is smallest at a certain point within the membrane's thickness (this is also called an "hourglass shape").

[0062] By using an asymmetric porous membrane and making the primary side a larger pore size, or in other words, making the primary side an open side, a pre-filtration effect can be produced.

[0063] The porous membrane may contain thermoplastic polymers such as PESU (polyethersulfone), PFA (perfluoroalkoxyalkane, a copolymer of tetrafluoroethylene and perfluoroalkoxyalkane), polyamide, and polyolefin, or it may contain polytetrafluoroethylene, etc. Among these, ultra-high molecular weight polyethylene is preferred as a material for porous membranes. Ultra-high molecular weight polyethylene refers to thermoplastic polyethylene with extremely long chains, and its molecular weight is over one million, typically preferably between 2 and 6 million.

[0064] The filters used in the filtration process may consist of two or more filters with different pore structures, and porous membrane filters and fiber membrane filters may be used in combination. A specific example is the use of a nylon fiber membrane filter and a UPE porous membrane filter.

[0065] Furthermore, it is preferable to thoroughly wash the filter before use. When using an unwashed filter (or a filter that has not been thoroughly washed), impurities contained in the filter are easily introduced into the chemical solution.

[0066] As described above, the filtration step according to the embodiment of the present invention may be a multi-stage filtration step in which the material to be purified is passed through two or more filters that differ in at least one of the group consisting of filter material, pore size, and pore structure. Furthermore, the substance to be purified may be passed through the same filter multiple times, or through multiple filters of the same type.

[0067] Furthermore, when preparing the chemical solution of the present invention, it is preferable to use a filter that can selectively remove metal components (especially metal ions), such as "Purasol SN 200nm" (metal component removal filter).

[0068] The material of the wetted parts (meaning the inner wall surface, etc., that may come into contact with the product to be purified and the chemical solution) of the purification apparatus used in the filtration process is not particularly limited, but it is preferable that they be made of at least one selected from the group consisting of non-metallic materials (such as fluororesins) and electropolished metallic materials (such as stainless steel) (hereinafter, these are collectively referred to as "corrosion-resistant materials"). For example, when the wetted parts of a manufacturing tank are made of a corrosion-resistant material, this means that the manufacturing tank itself is made of a corrosion-resistant material, or that the inner wall surface, etc., of the manufacturing tank is covered with a corrosion-resistant material.

[0069] The above non-metallic material is not particularly limited, and known materials can be used. Examples of nonmetallic materials include, but are not limited to, at least one selected from the group consisting of polyethylene resin, polypropylene resin, polyethylene-polypropylene resin, and fluororesins (e.g., tetrafluoroethylene resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer resin, tetrafluoroethylene-ethylene copolymer resin, trifluoroethylene chloride-ethylene copolymer resin, vinylidene fluoride resin, trifluoroethylene chloride copolymer resin, and vinyl fluoride resin).

[0070] The above-mentioned metal material is not particularly limited, and known materials can be used. Examples of metallic materials include those in which the combined content of chromium and nickel exceeds 25% by mass of the total mass of the metallic material, with 30% by mass or more being more preferable. There is no particular upper limit on the combined content of chromium and nickel in the metallic material, but generally 90% by mass or less is preferred. Examples of metallic materials include stainless steel and nickel-chromium alloys.

[0071] There are no particular restrictions on the stainless steel used, and any known stainless steel can be used. Among these, alloys containing 8% by mass or more nickel are preferred, and austenitic stainless steel containing 8% by mass or more nickel is more preferred. Examples of austenitic stainless steels include SUS (Steel Use Stainless) 304 (8% by mass Ni content, 18% by mass Cr content), SUS304L (9% by mass Ni content, 18% by mass Cr content), SUS316 (10% by mass Ni content, 16% by mass Cr content), and SUS316L (12% by mass Ni content, 16% by mass Cr content).

[0072] The nickel-chromium alloy is not particularly limited, and any known nickel-chromium alloy can be used. Among these, a nickel-chromium alloy with a nickel content of 40-75% by mass and a chromium content of 1-30% by mass is preferred. Examples of nickel-chromium alloys include Hastelloy (trade name, same hereinafter), Monel (trade name, same hereinafter), and Inconel (trade name, same hereinafter). More specifically, Hastelloy C-276 (Ni content 63% by mass, Cr content 16% by mass), Hastelloy-C (Ni content 60% by mass, Cr content 17% by mass), and Hastelloy C-22 (Ni content 61% by mass, Cr content 22% by mass). Furthermore, the nickel-chromium alloy may, if necessary, contain boron, silicon, tungsten, molybdenum, copper, and cobalt in addition to the alloys mentioned above.

[0073] The method for electropolishing the metal material is not particularly limited, and known methods can be used. For example, the methods described in paragraphs

[0011] to

[0014] of Japanese Patent Publication No. 2015-227501 and paragraphs

[0036] to

[0042] of Japanese Patent Publication No. 2008-264929 can be used.

[0074] It is presumed that, due to electropolishing, the chromium content in the passive layer of the metal material surface is higher than that in the matrix phase. Therefore, it is presumed that using a refining apparatus in which the wetted parts are made from electropolished metal material will reduce the likelihood of metal-containing particles leaking into the refined material. The metal material may be buffed. The buffing method is not particularly limited, and known methods can be used. The size of the abrasive grains used for finishing the buffing is not particularly limited, but #400 or smaller is preferred as it tends to reduce surface irregularities of the metal material. It is preferable that buffing be performed before electrolytic polishing.

[0075] (Other processes) The method for producing the chemical solution may further include steps other than the filtration step. Examples of steps other than the filtration step include a distillation step, a reaction step, and an electrostatic removal step.

[0076] (Distillation process) The distillation process involves distilling a material containing an organic solvent to obtain a distilled material. The method of distilling the material is not particularly limited, and known methods can be used. Typically, a distillation column is placed on the primary side of a purification apparatus used in the filtration process, and the distilled material is introduced into a production tank. In this case, the wetted parts of the distillation column are not particularly limited, but it is preferable that they be made of the corrosion-resistant material described above.

[0077] (Reaction process) The reaction step is a process of reacting raw materials to produce a product to be purified, which contains an organic solvent as a reactant. There are no particular limitations on the method of producing the product to be purified, and known methods can be used. Typically, a reaction vessel is placed on the primary side of the production tank (or distillation column) of the purification apparatus used in the filtration step, and the reactant is introduced into the production tank (or distillation column). In this case, there are no particular restrictions on the wetted parts of the manufacturing tank, but it is preferable that they be formed from the corrosion-resistant materials described above.

[0078] (static elimination process) The static elimination process is a process that removes static electricity from the material to be refined, thereby reducing its charge potential. There are no particular restrictions on the method of static elimination, and known static elimination methods can be used. One example of a static elimination method is to bring the object 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 seconds. Examples of conductive materials include stainless steel, gold, platinum, diamond, and glassy carbon. One method for bringing the material to be purified into contact with a conductive material is to place a grounded mesh made of a conductive material inside a conduit and pass the material to be purified through it.

[0079] The purification of the product to be purified, including all associated steps such as opening containers, cleaning containers and equipment, filling solutions, and analysis, is preferably carried out in a cleanroom. The cleanroom should preferably be a cleanroom with a cleanliness level of Class 4 or higher as defined by the international standard ISO 14644-1:2015 established by the International Organization for Standardization. Specifically, it is preferable that the cleanroom meets any of ISO Class 1, ISO Class 2, ISO Class 3, and ISO Class 4, more preferably ISO Class 1 or ISO Class 2, and even more preferably ISO Class 1.

[0080] While there are no particular restrictions on the storage temperature of the chemical solution, a storage temperature of 4°C or higher is preferable because it makes it less likely for trace amounts of impurities contained in the chemical solution to leach out, resulting in superior effects of the present invention.

[0081] <Chemical solution container> The chemical solution produced by the purification method described above may be stored in a container until use. Such a container, along with the liquid medicine contained within it, is collectively called a liquid medicine container. The liquid medicine is then taken out of the stored liquid medicine container and used.

[0082] For storing the above-mentioned chemical solution, a container with a high degree of cleanliness and minimal leaching of impurities is preferable for semiconductor device manufacturing applications. Examples of usable containers include, but are not limited to, the "Clean Bottle" series manufactured by Aicello Chemical Co., Ltd. and the "Pure Bottle" manufactured by Kodama Resin Industry Co., Ltd.

[0083] As for the container, it is preferable to use a multilayer bottle with a six-layer structure of six types of resins on the inner wall, or a multilayer bottle with a seven-layer structure of six types of resins, for the purpose of preventing contamination of the chemical solution with impurities. Examples of such containers include the container described in Japanese Patent Publication No. 2015-123351.

[0084] The wetted parts of this container may be made of the corrosion-resistant material already described (preferably electropolished stainless steel or fluororesin) or glass. In order to obtain better effects of the present invention, it is preferable that 90% or more of the wetted area is made of the above material, and more preferably that the entire wetted area is made of the above material.

[0085] The void ratio inside the container of the liquid medicine container is preferably 2 to 80 volume%, more preferably 2 to 50 volume%, and even more preferably 5 to 30 volume%. The above void ratio is calculated according to equation (1). Equation (1): Porosity = {1 - (Volume of liquid in the container / Volume of the container)} × 100 The container volume mentioned above is synonymous with the internal volume (capacity) of the container. By setting the porosity within this range, storage stability can be ensured by limiting contamination such as impurities. [Examples]

[0086] The present invention will be described in more detail below based on examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the examples shown below.

[0087] Furthermore, in preparing the chemical solutions for the examples and comparative examples, the handling of containers, preparation, filling, storage, and analytical measurements were all carried out in a cleanroom meeting ISO Class 2 or 1 standards.

[0088] (filter) The following filters were used: • "Purasol SN 200nm": UPE membrane (material), manufactured by Entegris, pore size 200nm • "PP 200nm": Polypropylene filter, manufactured by Entegris, pore size 200nm ·“Purasol SP 200nm”: UPE membrane (material) manufactured by Entegris, pore diameter 200nm • "Octolex 5nm": UPE Nylon filter graft, manufactured by Entegris, pore size 5nm • "IEX 15nm": Ion exchange resin filter, manufactured by Entegris, pore size 15nm • "IEX 50nm": Ion exchange resin filter, manufactured by Entegris, pore size 50nm • "IEX 200nm": Ion exchange resin filter, manufactured by Entegris, pore size 200nm • "PTFE 5nm": Polytetrafluoroethylene filter, manufactured by Entegris, pore size 5nm • "PTFE 7nm": Polytetrafluoroethylene filter, manufactured by Entegris, pore size 7nm • "PTFE 10nm": Polytetrafluoroethylene filter, manufactured by Entegris, pore size 10nm • "PTFE 20nm": Polytetrafluoroethylene filter, manufactured by Entegris, pore size 20nm • "Nylon 5nm": Nylon filter, manufactured by Pall, pore size 5nm • "UPE 1nm": Ultra-high molecular weight polyethylene filter, manufactured by Pall, pore size 1nm • "UPE 3nm": Ultra-high molecular weight polyethylene filter, manufactured by Pall, pore size 3nm • "UPE 5nm": Ultra-high molecular weight polyethylene filter, manufactured by Pall, pore size 5nm

[0089] <Product to be purified> The following organic solvents were used as materials to be purified for the preparation of the chemical solutions in the examples and comparative examples. • CyHe: Cyclohexanone • PGMEA: Propylene glycol monomethyl ether acetate MIBC: 4-methyl-2-pentanol nBA: Butyl acetate • EL: Ethyl lactate • PC: Propylene carbonate IPA: Isopropanol PGMEE: Propylene glycol monoethyl ether PGMPE: Propylene glycol monopropyl ether • CPN: Cyclopentanone Furthermore, "Raw Material 1" to "Raw Material 19" in the table indicate that the organic solvents used in each example and comparative example were purchased from the following manufacturers. "Raw material 1": Honeywell "Ingredient 2": Toyo Gosei "Raw material 3": BASF "Ingredient 4": Ube Industries "Ingredient 5": KH Neochem "Raw Material 6": Showa Denko "Raw material 7": KMG Electronic Chemical "Raw material 8":WAKO "Ingredient 9": KH Neochem "Raw material 10": Sanwa Yuka Kogyo "Raw material 11": Shell Global "Ingredient 12": Kanto Chemical "Raw material 13": Junyaku Hayashi "Raw material 14": CCP "Raw material 15": BASF "Raw material 16": ENF "Ingredient 17": Shiny "Ingredient 18": KH Neochem "Raw material 19": Junyaku Hayashi

[0090] <Container> The following containers were used to store the liquid medication. • EP-SUS: A container whose wetted parts are made of electropolished stainless steel.

[0091] <Purification Procedure> One of the above-mentioned materials to be purified was selected and subjected to the distillation purification process described in Table 1. In the table, "Yes-1" in the "Distillation and Purification" column indicates that atmospheric distillation was performed using a distillation column (theoretical plates: 15 stages), "Yes-2" indicates that reduced-pressure distillation was performed using a distillation column (theoretical plates: 25 stages), "Yes-3" indicates that reduced-pressure distillation was performed twice using a distillation column (theoretical plates: 30 stages), "Yes-4" indicates that atmospheric distillation was performed using a distillation column (theoretical plates: 20 stages), "Yes-5" indicates that atmospheric distillation was performed using a distillation column (theoretical plates: 10 stages), and "Yes-6" indicates that atmospheric distillation was performed using a distillation column (theoretical plates: 8 stages). However, "None" in the "Distillation Purification" column of the table indicates that distillation treatment was not performed, and in cases where the "Distillation Purification" column is "None," distillation purification was not carried out.

[0092] Next, the distilled and purified material was stored in a storage tank, and the material stored in the storage tank was filtered by passing it through filters 1 to 5 in the order shown in Table 1, and then stored in the storage tank. Next, the material to be purified stored in the storage tank was filtered through filters 6 and 7 as shown in Table 1. The material filtered through filter 7 was then circulated upstream of filter 6 and filtered again through filters 6 and 7 in a circulating filtration process. After circulating filtration, the chemical solution was placed in a container. In Examples 113 to 116, water was added to the chemical solution so that the moisture content reached a predetermined value.

[0093] Furthermore, during the series of purification processes described above, the wetted parts of various devices (e.g., distillation columns, piping, storage tanks, etc.) that came into contact with the product being purified were made of electropolished stainless steel.

[0094] The organic and metallic content of the chemical solution was measured using the method described below.

[0095] <Metal component content> The content of metal components (metal ions, metal-containing particles) in the chemical solution was measured using ICP-MS and SP-ICP-MS. The following equipment was used: • Manufacturer: PerkinElmer Model: NexION350S The following analysis software was used for the analysis. • Synngistix Nano-Application Module for “SP-ICP-MS” • Synngistix for ICP-MS software However, since metal-containing particles smaller than 10 nm cannot be measured by SP-ICP-MS, the identification method described above was used.

[0096] <Content of organic impurities> The content of organic impurities in various chemical solutions was analyzed using a gas chromatography-mass spectrometry (GC / MS) system (Agilent, GC: 7890B, MS: 5977B EI / CI MSD).

[0097] <Exam> [Pre-wetting solution or rinse solution] The defect-suppressing properties of the manufactured chemical solution when used as a pre-wetting or rinsing solution were evaluated using the method described below. First, a 300mm diameter silicon substrate, or a 300mm diameter silicon substrate with a silicon oxide film (a silicon substrate whose surface is covered with a silicon oxide film), was subjected to a spin-discharge of the chemical solution. While rotating the substrate, 0.5cc of each chemical solution was dispensed onto the substrate surface. The substrate was then spin-dried. Next, the number of defects present on the substrate after chemical solution application was measured using a KLA-Tencor SP-5 wafer inspection system (this measurement was taken as the measured value). Next, using EDAX (energy-dispersive X-ray spectroscopy), the types of defects were classified into metallic residue defects, composite residue defects, and stain-like residue defects. Metallic residue defects are residues derived from metal components, composite residue defects are residues derived from composites of organic matter and metal components, and stain-like residue defects are residues derived from organic matter. Furthermore, if the "metal residue defect on Si" is "D" or higher, it can be suitably used as a pre-wetting solution or rinsing solution.

[0098] <Individual evaluation (metal residue defects, composite residue defects, stain-like residue defects)> A: The number of defects corresponding to each board was 20 or less. B: The number of defects to be addressed was between 20 and 50 per board. C: The number of defects to be addressed exceeded 50 per board but was less than or equal to 100 per board. D: The number of defects to be addressed exceeded 100 per board, but was less than or equal to 150 per board. E: The number of defects to be addressed exceeded 150 per board.

[0099] [Developer] The following method was used to evaluate the chemical solution when used as a developer. First, a resist pattern was formed by the following procedure. A silicon substrate with a diameter of 300 mm, or a silicon substrate with a silicon oxide film with a diameter of 300 mm, was coated with a photosensitive or radiation-sensitive resin composition, as described later, and pre-baked (PB) at 100°C for 60 seconds to form a resist film with a thickness of 150 nm.

[0100] (Actinic ray-sensitive or radiation-sensitive resin composition) Acid-degradable resin (resin represented by the following formula (weight-average molecular weight (Mw): 7500): The values ​​indicated in each repeating unit represent mole percent): 100 parts by mass

[0101] [ka]

[0102] The photoacid generator shown below: 8 parts by mass

[0103] [ka]

[0104] The following quenchers are used: 5 parts by mass (the mass ratios from left to right are 0.1:0.3:0.3:0.2). Note that among the quenchers listed below, the polymer-type quenchers have a weight-average molecular weight (Mw) of 5000. The numbers indicated in each repeating unit represent the molar ratio.

[0105] [ka]

[0106] The hydrophobic resins shown below: 4 parts by mass (the mass ratio from left to right is 0.5:0.5). Of the hydrophobic resins below, the left hydrophobic resin has a weight-average molecular weight (Mw) of 7000, and the right hydrophobic resin has a weight-average molecular weight (Mw) of 8000. Note that the numerical values ​​indicated for each repeating unit in each hydrophobic resin represent the molar ratio.

[0107] [ka]

[0108] solvent: PGMEA (Propylene Glycol Monomethyl Ether Acetate): 3 parts by mass Cyclohexanone: 600 parts by mass γ-BL (γ-butyrolactone): 100 parts by mass

[0109] A wafer with a resist film formed on it was scanned using an ArF excimer laser scanner (Numerical Aperture: 0.75) at 25 mJ / cm². 2 Pattern exposure was performed. Then, the wafer was heated at 120°C for 60 seconds. Next, the wafer was developed by paddled in each developer (chemical) for 30 seconds. Then, the wafer was rotated at a rotation speed of 4000 rpm for 30 seconds to form a negative resist pattern. After that, the obtained negative resist pattern was heated at 200°C for 300 seconds. Through the above process, an L / S pattern with a line / space ratio of 1:1 (average pattern width: 45 nm) was obtained. The presence or absence of the aforementioned metal residue defects, composite residue defects, and stain-like residue defects in the space portion of the obtained sample was evaluated according to the method described above.

[0110] In each example, the pressure difference between each filter was 0.01 to 0.03 MPa. In Table 1, "Usage 1" in the "Usage" column means that the above test was carried out using the chemical solutions described in each example and comparative example as the pre-wetting solution and rinse solution. "Usage 2" in the "Usage" column means that the above test was carried out using the chemical solutions described in each example and comparative example as the developer. In the table, "Metal Residue on Si" shows the evaluation results for metal residue defects on a silicon substrate, "Composite Residue on Si" shows the evaluation results for composite residue defects on a silicon substrate, "Stain-like Residue on Si" shows the evaluation results for stain-like residue defects on a silicon substrate, "Metal Residue on SiO2" shows the evaluation results for metal residue defects on a silicon substrate with a silicon oxide film, and "Composite Residue on SiO2" shows the evaluation results for composite residue defects on a silicon substrate with a silicon oxide film.

[0111] In Table 1, the "Ag ion content (mass ppt)" column represents the content of silver ions (mass ppt) relative to the total mass of the drug solution. The "Metal component content (mass ppt)" column represents the content of metal components (mass ppt) relative to the total mass of the drug solution. The "Ag oxide particles / Ag ions" column represents a mass ratio of 1 for the content of silver oxide particles to the content of silver ions. The "Pt ion content (mass ppt)" column represents the content of platinum ions (mass ppt) relative to the total mass of the drug solution. The "Au ion content (mass ppt)" column represents the content of gold ions (mass ppt) relative to the total mass of the drug solution. The "Number of titanium oxide particles" column represents the number of titanium oxide particles in the drug solution. The "Ti oxide particles / Ag oxide particles" column represents the ratio of titanium oxide particles to the content of silver oxide particles. The "Ag oxide particle percentage (mass %)" column represents the content of silver oxide particles (mass %) relative to the content of silver components in the metal components. The "Ti Oxide Particle Percentage (mass%)" column represents the mass percentage of titanium oxide particles relative to the titanium content in the metal component. The "Cu Oxide Particles / Cu Ions" column represents the mass ratio of Cu oxide particles to Cu ions. The "Fe Oxide Particles / Fe Ions" column represents the mass ratio of Fe oxide particles to Fe ions. The "Percentage of 0.5-17nm Ti Oxide Particles (mass%)" column represents the mass percentage of titanium oxide particles with a particle size of 0.5-17nm. The "Moisture Content" column represents the water content in the solution relative to the total mass of the solution (mass ppb). Also, in Table 1, "E + number" means "10 数字 This represents "3.5E+04", for example, "3.5×10 4 This represents ". In Table 1, "<1" indicates a value less than 1. In Table 1, "<500 ppb" indicates less than 500 mass ppb.

[0112] [Table 1]

[0113] [Table 2]

[0114] Table 3

[0115] Table 4

[0116] Table 5

[0117] Table 6

[0118] Table 7

[0119] Table 8

[0120] Table 9

[0121] Table 10

[0122] Table 11

[0123] Table 12

[0124] Table 13

[0125] Table 14

[0126] Table 15

[0127] Table 16

[0128] Table 17

[0129] Table 18

[0130] Table 19

[0131] Table 20

[0132] Table 21

[0133] Table 22

[0134] Table 23

[0135] [Table 24]

[0136] [Table 25]

[0137] [Table 26]

[0138] [Table 27]

[0139] [Table 28]

[0140] [Table 29]

[0141] [Table 30]

[0142] In Table 1, the data relating to each example and comparative example is shown in Table 1 [Part 1]. <1> ~ <6> Table 1 [Part 2] <1> ~ <6> Table 1 [Part 3] <1> ~ <6> Table 1 [Part 4] <1> ~ <6> , and Table 1 [Part 5] <1> ~ <6> This was shown across each line. For example, in Example 1, see Table 1 [Part 1] <1> As shown, using CyHe as the organic solvent, Table 1 [Part 1] <2> As shown in Table 1 [Part 1], filter 2 is "IEX 15nm". <3> As shown in Table 1 [Part 1], the amount of Ag ions in the drug solution is 0.8 mass ppt. <4> As shown in Table 1 [Part 1], the number of Ti oxide particles is 2.1E+04. <5> As shown in Table 1 [Part 1], the number of "oxidized Fe particles / Fe ions" is 8.7E+4. <6> As shown, the evaluation of "metal residue on Si" is "A". The same applies to the other examples and comparative examples.

[0143] The results shown in the table confirm that the drug solution of the present invention can achieve the desired effect. In particular, a comparison of Examples 1-7 (Examples 29-35, 57-63, and 85-91) confirmed that the effect was superior when the silver ion content was 0.0020-0.90 ppt by mass relative to the total mass of the drug solution. Furthermore, a comparison of Examples 8-13 (Examples 36-41, 64-69, and 92-97) confirmed that the effect is superior when the metal component content is 10.0-500 ppt by mass relative to the total mass of the drug solution. Furthermore, a comparison of Examples 14-18 (Examples 42-46, 70-74, and 98-102) confirmed that the effect is superior when the mass ratio of silver oxide particles to silver ions is between 0.00000010 and 0.1. Furthermore, a comparison of Examples 4-7 (Examples 32-35, 60-63, and 88-91) confirmed that the effect is superior when the platinum ion or gold ion content is 0.000010-1.0 ppt by mass relative to the total mass of the drug solution. Furthermore, a comparison of Examples 19-22 (Examples 47-50, 75-78, and 103-106) showed that the number of titanium dioxide particles was 10 2 ~10 10 It was confirmed that the effect is superior when used individually. Furthermore, a comparison of Examples 23-26 (Examples 51-54, 79-82, and 107-110) shows that the ratio of titanium oxide particles to silver oxide particles is 10 2 ~10 10 In that case, it was confirmed that the effect was superior. Furthermore, a comparison of Examples 14-18 (Examples 42-46, 70-74, and 98-102) confirmed that the effect is superior when the content of silver oxide particles is 0.00010-5.0% by mass relative to the content of silver in the metal component. Furthermore, a comparison of Examples 14-18 (Examples 42-46, 70-74, and 98-102) confirmed that the effect is superior when the titanium oxide particle content is 5% by mass or more and less than 98% by mass relative to the titanium content in the metal component. Furthermore, a comparison of Examples 23-26 (Examples 51-54, 79-82, and 107-110) confirmed that the effect is superior when the proportion of titanium dioxide particles with a particle size of 0.5-17 nm is 40% by mass or more and less than 99% by mass. Furthermore, from Examples 27 and 28 (55 and 56, 83 and 84, 111 and 112), it was confirmed that the effect is superior when the content of organic impurities is 1,000 to 100,000 ppt by mass relative to the total mass of the chemical solution. Furthermore, from Examples 1 and 2, it was confirmed that the effect is superior when the moisture content is 500 ppb or less by volume.

[0144] After cleaning the container (EP-SUS) and the various devices used in the <purification procedure> with the chemical solution (100 L) from Example 29, the chemical solution from Example 29, prepared separately, was passed through the cleaned devices and collected in the cleaned container to obtain solution A in the container. Furthermore, after cleaning the container (EP-SUS) and the various devices used in the <purification procedure> with the chemical solution (100 L) from Example 40, the chemical solution from Example 29, which was prepared separately, was passed through the cleaned devices and collected in the cleaned container to obtain solution B in the container. When "metal residue defects on Si" were evaluated using solution A and solution B, solution A yielded better results.

[0145] <Example (EUV exposure)> First, resist composition 1 was obtained by mixing each component in the following composition. ·Resin (A-1): 0.77g • Photoacid generator (B-1): 0.03g Basic compound (E-3): 0.03g • PGMEA (commercial product, high-purity grade): 67.5g Ethyl lactate (commercial product, high-purity grade): 75g

[0146] • Resin (A-1) The following resin was used as resin (A-1).

[0147] [ka]

[0148] • Photoacid generator (B-1) The following compound was used as the photoacid generator (B-1).

[0149] [ka]

[0150] • Basic compounds (E-3) The following compounds were used as the basic compound (E-3).

[0151] [ka]

[0152] (Pattern formation and evaluation) First, resist composition 1 was applied to a silicon wafer with a diameter of 300 mm, and a pre-bake (PB) was performed at 100°C for 60 seconds to form a resist film with a thickness of 30 nm.

[0153] This resist film was exposed using an EUV lithography machine (ASML; NXE3350, NA 0.33, Dipole 90°, Outer Sigma 0.87, Inner Sigma 0.35) via a reflective mask. Afterward, it was heated at 85°C for 60 seconds (PEB: Post Exposure Bake). Next, the film was developed by spraying a developer (butyl acetate / FETW) for 30 seconds, and then rinsed by dispensing a rinse solution onto the silicon wafer for 20 seconds using a rotary coating method. Subsequently, the silicon wafer was rotated at 2000 rpm for 40 seconds to form a line-and-space pattern with a space width of 20 nm and a pattern line width of 15 nm. The rinse solution used was the same chemical solution used in Example 80 described above. Furthermore, when the various evaluations described above were performed, the desired effect was obtained with a trend similar to that shown in Table 1.

Claims

1. A chemical solution containing an organic solvent and a metal component, The aforementioned metal component contains silver ions, The silver ion content is 0.0010 to 1.0 ppt by mass relative to the total mass of the drug solution. The aforementioned metal component contains gold ions, The gold ion content is 0.000010 to 1.0 mass ppt with respect to the total mass of the chemical solution. The content of the aforementioned metal component is 10.0 to 500 ppt by mass relative to the total mass of the chemical solution. The aforementioned metal component contains silver oxide particles, The mass ratio of the content of silver oxide particles to the content of silver ions is 0.00000010 to 0.

1. The organic solvent is selected from the group consisting of propylene glycol monomethyl ether acetate, cyclohexanone, 4-methyl-2-pentanol, and butyl acetate. The content of the aforementioned organic solvent is more than 99.95% by mass of the total mass of the chemical solution. A chemical solution used as a pre-wetting solution, developer, or rinse solution.

2. The drug solution according to claim 1, wherein the content of the silver oxide particles is 0.00010 to 5.0% by mass relative to the content of the silver component in the metal component.

3. The aforementioned metal component contains titanium oxide particles and titanium ions. The drug solution according to claim 1 or 2, wherein the mass ratio 2 of the content of titanium oxide particles to the content of titanium ions satisfies the relationship of formula (A) below to the mass ratio 1. Formula (A) Mass ratio 2 > mass ratio 1

4. The drug solution according to claim 3, wherein the ratio of the content of titanium oxide particles to the content of silver oxide particles is 102 to 1010.

5. The drug solution according to claim 3 or 4, wherein the content of the titanium oxide particles is 5% by mass or more and less than 98% by mass relative to the content of the titanium component in the metal component.

6. The drug solution according to any one of claims 3 to 5, wherein the proportion of titanium oxide particles having a particle size of 0.5 to 17 nm is 40% by mass or more and less than 99% by mass.

7. The aforementioned metal component contains copper oxide particles and copper ions. The drug solution according to any one of claims 1 to 6, wherein the mass ratio of the content of copper oxide particles to the content of copper ions, 3, and the mass ratio of copper oxide particles to copper ions, 1, satisfy the following formula (B). Formula (B) Mass ratio 3 > mass ratio 1

8. The aforementioned metal component contains iron oxide particles and iron ions. The drug solution according to any one of claims 1 to 6, wherein the mass ratio of the content of iron oxide particles to the content of iron ions, 4, and the mass ratio of 1, satisfy the following formula (C). Formula (C) Mass ratio 4>mass ratio 1

9. The aforementioned metal component contains platinum ions, The drug solution according to any one of claims 1 to 8, wherein the content of the platinum ions is 0.000010 to 1.0 ppt by mass with respect to the total mass of the drug solution.

10. Furthermore, it contains organic impurities, The drug solution according to any one of claims 1 to 9, wherein the content of the organic impurity is 1,000 to 100,000 ppt by mass with respect to the total mass of the drug solution.

11. The drug solution according to any one of claims 1 to 10, wherein the water content relative to the total mass of the drug solution is 500 ppb by mass or less.

12. A drug solution container comprising a container and a drug solution according to any one of claims 1 to 11 contained in the container.

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