Cleaning liquid and cleaning method

Abstract

The present invention employs a cleaning liquid containing a solvent and a metal remover. In the cleaning liquid, two or more solvents are included, the distance (HSP distance) between the Hansen solubility parameter of the cleaning liquid and the Hansen solubility parameter of dimethylacetamide is 1.0 or less, and the content of metal impurities is 0.1 × 10-9 parts by mass or more and 102 × 10-6 parts by mass or less with respect to 100 parts by mass of the total of the solvent and the metal remover. This cleaning liquid improves impurity removal.

Description

Cleaning solution and cleaning method

[0001] This application claims priority to Japanese Patent Application No. 2023-187033, filed on October 31, 2023, the contents of which are incorporated herein by reference.

[0002] The cleaning solution must be selected depending on the type of contamination and the material of the object to be cleaned. In the industrial field, for example, films manufactured from polymeric materials, particularly porous films, are affected by organic impurity contamination such as polymer residues derived from the polymeric material, or metal impurity contamination derived from metal catalysts used in the film manufacturing process. To address this issue, a membrane cleaning solution has been proposed in which a specific solvent is selected to suit the material of the film (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2017-202479

[0004] Conventionally, filters manufactured from porous films have sometimes been subject to unintended contamination of chemical solutions purified through the filters. The sources of contamination are high-molecular-weight or low-molecular-weight organic impurities or metal impurities present in the filters. These impurities not only originate from the polymeric material or metal catalyst, but are also easily introduced from various sources in the production line, such as the piping, containers, and equipment used. Meanwhile, with the trend toward smaller, more sophisticated industrial products, there is a strong demand for further reductions in impurity contamination. The present invention was developed in light of the above circumstances, and aims to provide a cleaning solution with improved impurity removal capabilities and a cleaning method using this cleaning solution.

[0005] In order to solve the above problems, the present invention employs the following configuration.

[0006] A first aspect of the present invention is a cleaning solution containing a solvent and a metal remover, the cleaning solution containing two or more solvents, wherein the distance (HSP distance) between the Hansen solubility parameter of the cleaning solution and the Hansen solubility parameter of dimethylacetamide is 1.0 or less, and the content of metal impurities is 0.1 × 10 relative to 100 parts by mass of the total of the solvent and the metal remover. －９ Mass part or more 10 ２ x10－６ It is a cleaning solution having a content of less than or equal to parts by mass.

[0007] A second aspect of the present invention is a cleaning method for cleaning an object by bringing the cleaning liquid according to the first aspect into contact with the object.

[0008] According to the present invention, it is possible to provide a cleaning solution with improved impurity removal properties and a cleaning method using the cleaning solution. Such a cleaning solution and a cleaning method using the cleaning solution are useful for removing impurity stains from various objects to be cleaned.

[0009] (First Aspect: Cleaning Solution) One embodiment of the cleaning solution contains two or more solvents and a metal remover. In this embodiment, the distance (HSP distance) between the Hansen solubility parameter of the cleaning solution and the Hansen solubility parameter of dimethylacetamide is 1.0 or less. In addition, in the cleaning solution of this embodiment, the content of metal impurities is 0.1 x 10 per 100 parts by mass of the total of the solvent and the metal remover. －９ Mass part or more 10 ２ x10 －６ parts by mass or less.

[0010] <Solvent> The cleaning solution of this embodiment contains two or more solvents. The solvent contained in the cleaning solution of this embodiment can be appropriately selected from known organic solvents so that the HSP distance is 1.0 or less. Examples of the organic solvent include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, ether solvents, sulfoxide solvents, and sulfone solvents; and nonpolar solvents such as hydrocarbon solvents. As described below, some organic solvents contain multiple types of functional groups in their structure that characterize the above solvents. In such cases, the term "solvent" refers to any solvent type containing the functional groups possessed by the organic solvent. For example, diethylene glycol monomethyl ether is considered to fall into both the alcohol solvents and the ether solvents in the above classifications.

[0011] <Ketone Solvents> Ketone solvents are organic solvents containing C-C(=O)-C in their structure. Specific examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, ionone, diacetonyl alcohol, acetyl carbinol, acetophenone, methyl naphthyl ketone, and methyl amyl ketone (2-heptanone). Furthermore, the ketone solvent may be a cyclic ketone solvent. Specific examples of the cyclic ketone solvent include cyclohexanone (CH), methylcyclohexanone, isophorone, propylene carbonate, ethylene carbonate, and dihydrolevoglucosenone (silene).

[0012] <Ester Solvent> An ester solvent is an organic solvent containing C—C(═O)—O—C in its structure. Specific examples of ester solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2 -ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, lactic acid Propyl, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, and the like.The ester solvent may also be a cyclic ester solvent (lactone solvent). Specific examples of the lactone solvent include γ-butyrolactone (GBL), ε-caprolactone, γ-valerolactone, and δ-valerolactone.

[0013] <Alcohol-Based Solvents> Alcohol-based solvents are organic solvents that contain an alcoholic hydroxy group in their structure. The term "alcoholic hydroxy group" refers to a hydroxy group bonded to a carbon atom of an aliphatic hydrocarbon group. Specific examples of alcohol-based solvents include 2-propanol (isopropanol), 1-butanol (n-butanol), 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol, ethylene glycol, diethylene glycol, propylene glycol (PG), and dipropylene glycol.

[0014] Nitrile Solvents Nitrile solvents are organic solvents containing a nitrile group in their structure. Specific examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0015] Amide Solvents Amide solvents are organic solvents containing an amide group in their structure. Specific examples of amide solvents include chain amide solvents such as dimethylacetamide (DMAc), dimethylformamide, and tetramethylurea; and cyclic amide (lactam) solvents such as dimethylimidazolidinone, N-methylpyrrolidone, 1-ethyl-2-pyrrolidone, and 1-butyl-2-pyrrolidone.

[0016] Ether Solvents Ether solvents are organic solvents containing C—O—C in their structure. Specific examples of ether solvents include ethylene glycol monomethyl ether (EGME), ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether (PGEE), propylene glycol monopropyl ether, propylene glycol monobutyl ether, and diisopropylene glycol monomethyl ether.

[0017] Sulfoxide-based solvents are organic solvents containing a sulfinyl group —S(═O)— in their structure. Specific examples of sulfoxide-based solvents include dimethyl sulfoxide (DMSO).

[0018] Sulfone solvents have a sulfonyl group -S(=O) in the structure. ２ Specific examples of sulfone-based solvents include sulfolane.

[0019] <Hydrocarbon Solvent> The hydrocarbon solvent is a hydrocarbon solvent that is composed of an optionally halogenated hydrocarbon and has no substituents other than halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. Specific examples of the hydrocarbon solvent include n-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, and n-hexadecane.

[0020] The two or more solvents in the cleaning solution of this embodiment are preferably a mixed solvent of two or more solvents selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, and ether solvents, more preferably a mixed solvent of two or more solvents selected from the group consisting of ketone solvents, ester solvents, and ether solvents, and even more preferably a mixed solvent containing two or more solvents selected from the group consisting of ester solvents and ether solvents. In this specification, the two or more solvents may be two or more solvents of the same classification as long as they contain two types of compounds. For example, the two or more solvents may be a mixed solvent of 1-octanone and cyclohexanone, both of which are ketone solvents.

[0021] <Metal Remover> Examples of the metal remover contained in the cleaning solution of this embodiment include a metal chelating agent and an organic acid.

[0022] <<Metal Chelating Agent>> Examples of the metal chelating agent in this embodiment include aminocarboxylic acid chelating agents such as ethylenediaminetetraacetic acid, nitrilotriacetic acid, and diethylenetriaminepentaacetic acid; phosphonic acid chelating agents such as 1-hydroxyethane-1,1-diphosphonic acid and nitrilotris(methylenephosphonic acid); and compound (A1) represented by the following general formula (a-1) (hereinafter also simply referred to as "compound (A1)"). Among these, compound (A1) is preferred as the metal chelating agent.

[0023] [In the formula, Ra １ and Ra ２ are each independently an alkyl group having 1 to 3 carbon atoms. ３ and Ra ４ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. １ and Ya ２ are each independently a single bond, —O—, —S— or —N(Ra ５ )-. Ra ５ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n is an integer of 0 to 3.

[0024] In the formula (a-1), Ra １ ~Ra ５ Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. １ and Ra ２ are each independently preferably a methyl group or an ethyl group, more preferably a methyl group. ３ and Ra ４ are preferably each a hydrogen atom. １ is preferably a single bond or —O—, more preferably a single bond. ２ is preferably a single bond or —O—, and more preferably a single bond. n is preferably 1 or 2, and more preferably 1.

[0025] Among the above, the compound (A1) is preferably acetylacetone (AcAc) or acetonylacetone, and more preferably acetylacetone (AcAc). In the cleaning liquid of the present embodiment, one metal chelating agent may be used alone, or two or more metal chelating agents may be used in combination.

[0026] <Organic Acid> Examples of the organic acid in the present embodiment include carboxylic acids such as lactic acid (LA), citric acid, malic acid, formic acid, acetic acid, oxalic acid, 2-nitrophenylacetic acid, 2-ethylhexanoic acid, and dodecanoic acid; sugar acids such as ascorbic acid and glucuronic acid; sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid; and phosphoric acid and phosphate esters such as bis(2-ethylhexyl)phosphoric acid.

[0027] Among the above, the organic acid is preferably a carboxylic acid, more preferably a hydroxy acid, and even more preferably at least one selected from the group consisting of lactic acid, citric acid, and malic acid, with lactic acid being particularly preferred. In the cleaning solution of the present embodiment, one organic acid may be used alone, or two or more organic acids may be used in combination.

[0028] The cleaning liquid of the present embodiment preferably contains two or more metal removers. The cleaning liquid of the present embodiment preferably contains two or more metal removers selected from the group consisting of the metal chelating agents and organic acids described above, more preferably contains two or more metal removers selected from the group consisting of the compound (A1) described above and organic acids, and further preferably contains two or more metal removers selected from the group consisting of the compound (A1) described above and carboxylic acids.

[0029] In the cleaning liquid of the present embodiment, among the above, it is preferable to use the above-described metal chelating agent and an organic acid in combination, it is more preferable to use the above-described compound (A1) and an organic acid in combination, and it is even more preferable to use the above-described compound (A1) and a carboxylic acid in combination.

[0030] <Optional Components> The cleaning solution of the present embodiment may contain optional components other than the solvent and metal remover described above, as long as the optional components do not impair the effects of the present invention. Examples of the optional components include a pH adjuster and a surfactant.

[0031] [Distance between Hansen Solubility Parameters (HSP Distance)] The cleaning solution of this embodiment contains the two or more solvents and the metal remover described above, and the distance (HSP distance) between the Hansen solubility parameter of the cleaning solution and the Hansen solubility parameter of dimethylacetamide (DMAc) is 1.0 or less, preferably 0.8 or less, and more preferably 0.5 or less. If the HSP distance of the cleaning solution of this embodiment is equal to or less than the upper limit described above, the effect of the cleaning solution in removing impurities and dirt is enhanced regardless of the material of the object to be cleaned. The lower the HSP distance of the cleaning solution of this embodiment, the more preferable it is, as this enhances the effect of the cleaning solution in removing impurities and dirt.

[0032] As used herein, the term "Hansen Solubility Parameter" refers to a numerical constant that is theoretically calculated and is a useful tool for predicting the ability of a solvent material to dissolve a particular solute. The Hansen Solubility Parameter is a combination of the following three experimentally and theoretically derived Hansen Solubility Parameters (δ ｄ (dispersion force term), δ ｐ (polar term) and δ ｈThe Hansen solubility parameter (HSP) is a measure of the overall strength and selectivity of a material. The Hansen solubility parameter is expressed in units of MPa. ０．５ or (J / cc) ０．５ It is given by δ ｄ : Energy derived from intermolecular dispersion forces δ ｐ : Energy derived from intermolecular polar forces δ ｈ : Energy derived from intermolecular hydrogen bonding forces

[0033] "Hansen Solubility Parameters" can be calculated, for example, by "Molecular Modeling Pro" software, version 5.1.9 (ChemSW, Fairfield CA, www.chemsw.com) or Hansen Solubility from Dynacomp Software.

[0034] Since the cleaning solution of this embodiment is a mixture, the Hansen solubility parameter of the cleaning solution of this embodiment can be determined as follows. １ (δ ｄｓ１ , δ ｐｓ１ , δ ｈｓ１ ), solvent S ２ (δ ｄｓ２ , δ ｐｓ２ , δ ｈｓ２ ), Metal Remover B １ (δ ｄＢ１ , δ ｐＢ１ , δ ｈＢ１ ) and metal remover B ２ (δ ｄＢ２ , δ ｐＢ２ , δ ｈＢ２ ) a cleaning solution CS consisting of a solvent S １ The amount of the solvent S ２ The compounding amount of b, metal remover B １ The compounding amount of c and metal remover B ２ When the blending amount of is d, the δ ｄｃｓ (dispersion force term), δ ｐｃｓ (polar term) and δ ｈｃｓ (Hydrogen bond term) is calculated by the following formula: where a + b + c + d = 100. ｄｃｓ = (δ ｄｓ１× a + δ ｄｓ２ ×b+δ ｄＢ１ ×c+δ ｄＢ２ × d) / 100 δ ｐｃｓ = (δ ｐｓ１ × a + δ ｐｓ２ ×b+δ ｐＢ１ ×c+δ ｐＢ２ × d) / 100 δ ｈｃｓ = (δ ｈｓ１ × a + δ ｈｓ２ ×b+δ ｈＢ１ ×c+δ ｈＢ２ ×d) / 100

[0035] The distance (HSP distance) between the Hansen solubility parameter of the cleaning solution CS (the cleaning solution of this embodiment) and the Hansen solubility parameter of dimethylacetamide (DMAc) is calculated by the following formula (1): HSP distance = {4(δ ｄｃｓ -δ ｄＤＭＡｃ ) ２ + (δ ｐｃｓ -δ ｐＤＭＡｃ ) ２ + (δ ｈｃｓ -δ ｈＤＭＡｃ ) ２} ０．５ ... (1) The dispersion force term of dimethylacetamide (δ ｄＤＭＡｃ ) is 16.8, and the polar term (δ ｐＤＭＡｃ ) is 11.5, and the hydrogen bond term (δ ｈＤＭＡｃ ) uses a value of 9.4.

[0036] The HSP distance in the cleaning solution of this embodiment is, for example, the dispersion force term (δ ｄＤＭＡｃ ), polar term (δ ｐＤＭＡｃ ) and the hydrogen bond term (δ ｈＤＭＡｃ The value of the metal removal agent can be controlled by selecting a solvent or a metal removal agent close to the value of the metal removal agent, or by selecting a combination of each component.

[0037] [Content of Metal Impurities] The cleaning solution of the present embodiment has a content of metal impurities of 0.1 × 10 per 100 parts by mass of the total of the solvent and the metal remover. －９ Mass part or more 10 ２ x10 －６ parts by mass or less, 0.25 x 10 －９ Mass part or more 1 x 10 －６(1000 x 10 －９ ) parts by mass or less, and －９ Mass part or more 500×10 －９ Parts by mass or less are more preferable, and 0.75 × 10 －９ Mass part or more 100×10 －９ It is more preferable that the amount is 1×10 parts by mass or less. －９ Mass part or more 20×10 －９ In the cleaning solution of the present embodiment, if the content of metal impurities is within the above range, the effect of the cleaning solution in removing impurities and dirt is further enhanced regardless of the material of the object to be cleaned.

[0038] The "metal impurities" contained in the cleaning solution of this embodiment refer to metal components including metal elements selected from the group consisting of Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr, and Mg. The "content of metal impurities" refers to the total content of metal components including metal elements selected from the group consisting of Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr, and Mg.

[0039] The mass of metal impurities in the cleaning solution is determined by inductively coupled plasma mass spectrometry. In practice, the metal elements to be measured are identified, and the total amount is measured to determine the content (mass fraction) of the metal impurities in the cleaning solution. The metal elements to be measured are, for example, 12 to 28 elements, including Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr, and Mg, as well as any of the following metal elements: Li, V, Mn, Co, Cu, Ge, As, Sr, Zr, Mo, Ag, Cd, Sn, Sb, Ba, W, Au, and Pb.

[0040] The content of metal impurities in the cleaning solution can be adjusted by controlling the amount of metal impurities contained in the solvent or metal remover to be formulated; alternatively, it can be adjusted by mixing the solvent, metal remover, and optional components and then adding a metal element separately from these; alternatively, it can be adjusted by separating and removing excess metal elements.

[0041] The cleaning solution of the present embodiment is a composition containing a mixed solvent of two or more solvents selected from the group consisting of ketone-based solvents, ester-based solvents, alcohol-based solvents, and ether-based solvents, the metal chelating agent described above, and the organic acid described above, wherein the HSP distance is 1.0 or less, and the content of metal impurities is 0.1 × 10 relative to 100 parts by mass of the total of the mixed solvent, the metal chelating agent, and the organic acid. －９ Mass part or more 10 ２ x10 －６ Parts by mass or less of the composition (X) are preferred.

[0042] The distance (HSP distance) between the Hansen solubility parameter of the composition (X) and the Hansen solubility parameter of DMAc is 1.0 or less, preferably 0.8 or less, more preferably 0.5 or less, even more preferably 0.4 or less, particularly preferably 0.3 or less, and the lower the value, the more preferable.

[0043] The mixed solvent in the composition (X) is more preferably a mixed solvent of one or more solvents selected from the group consisting of ketone-based solvents and ester-based solvents (hereinafter also referred to as "solvent S1") and one or more solvents selected from the group consisting of alcohol-based solvents and ether-based solvents (hereinafter also referred to as "solvent S2"), even more preferably a mixed solvent of an ester-based solvent and an ether-based solvent, and particularly preferably a mixed solvent of a lactone-based solvent and an ether-based solvent.

[0044] For example, when the two or more solvents in the composition (X) are a mixed solvent of solvent S1 and solvent S2, the mixing ratio of solvent S1 to solvent S2 (solvent S1:solvent S2) is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40, by mass.

[0045] Suitable combinations of two or more solvents in composition (X) include a mixed solvent of one or more solvents selected from the group consisting of γ-butyrolactone, ε-caprolactone, and γ-valerolactone with one or more solvents selected from the group consisting of EGME, PGME, and PGEE; a mixed solvent of dihydrolevoglucosenone (silene) and PG, etc. Among these, a suitable combination of two or more solvents is preferably a mixed solvent of one or more solvents selected from the group consisting of γ-butyrolactone, ε-caprolactone, and γ-valerolactone with one or more solvents selected from the group consisting of EGME, PGME, and PGEE, and more preferably a mixed solvent of γ-butyrolactone and PGME.

[0046] The metal chelating agent in the composition (X) is preferably the compound (A1), more preferably acetylacetone (AcAc).The organic acid in the composition (X) is preferably a carboxylic acid, more preferably a hydroxy acid, and even more preferably lactic acid.

[0047] In the composition (X), the content of metal impurities is 0.1 × 10 relative to 100 parts by mass of the total of the mixed solvent, the metal chelating agent, and the organic acid. －９ Mass part or more 10 ２ x10 －６ parts by mass or less, 0.25 x 10 －９ Mass part or more 1 x 10 －６ (1000 x 10 －９ ) parts by mass or less, and －９ Mass part or more 500×10 －９ Parts by mass or less are more preferable, and 0.75 × 10 －９ Mass part or more 100×10 －９ It is more preferable that the amount is 1×10 parts by mass or less. －９ Mass part or more 20×10 －９ Parts by mass or less are particularly preferred.

[0048] In the composition (X), the contents of the mixed solvent, the metal chelating agent, and the organic acid are appropriately selected so that the HSP distance is 1.0 or less. The content of the mixed solvent in the composition (X) is preferably 90 to 99.5 mass%, more preferably 95 to 99 mass%, based on the total amount of the composition (X).

[0049] The content of the metal chelating agent in the composition (X) is preferably 0.1 to 9 mass%, more preferably 0.5 to 9 mass%, and even more preferably 0.5 to 5 mass%, based on the total amount of the composition (X). The proportion of the compound (A1) in the metal chelating agent is preferably 50 mass% or more, more preferably 75 mass% or more, and may be 100 mass%, based on the total mass of the metal chelating agent.

[0050] The content of the organic acid in the composition (X) is preferably 0.1 to 9% by mass, more preferably 0.5 to 9% by mass, and even more preferably 0.5 to 5% by mass, relative to 100% by mass of the total amount of the composition (X). The proportion of carboxylic acid in the organic acid is preferably 50% by mass or more, more preferably 75% by mass or more, and may be 100% by mass, relative to the total mass of the organic acid.

[0051] The composition (X) may further contain the above-mentioned optional components, in addition to the mixed solvent, metal chelating agent, and organic acid, as necessary.

[0052] The cleaning solution of this embodiment is useful for cleaning membranes. The form and shape of the membrane are not particularly limited, and examples thereof include flat membranes, hollow fiber membranes, tubular membranes, spiral membranes, thin films, etc. The material of the membrane is also not particularly limited, and examples thereof include polyolefins (polyethylene, polypropylene, etc.), polysulfones, polyacrylonitriles, polyamides, polyimides, polyvinyl alcohols, cellulose acetates, fluoropolymers, ceramics, etc.

[0053] The cleaning solution of this embodiment is also useful for removing impurities and dirt from various objects to be cleaned. Examples of various objects to be cleaned include pipes in a production line, containers used, and tools. For example, the cleaning solution of this embodiment can be used to clean objects selected from the group consisting of metal pipes, resin pipes, glass pipes, metal joints, resin joints, glass joints, filters, chemical containers, measurement cells, and chromatography columns.

[0054] The cleaning solution of the present embodiment described above contains two or more solvents and a metal remover, and in addition, the distance (HSP distance) between the Hansen solubility parameter of the cleaning solution and the Hansen solubility parameter of dimethylacetamide (DMAc) is 1.0 or less, and the content of metal impurities is 0.1 × 10 relative to 100 parts by mass of the total of the solvent and the metal remover. －９ Mass part or more 10 ２ x10 －６ The content is less than parts by mass. Although the reason is unclear, this cleaning solution exhibits good cleaning and removal effects on both polar and non-polar objects by adjusting the Hansen solubility parameter of the entire cleaning solution to approach that of DMAc and by containing a metal remover. In addition, the presence of a metal remover results in excellent removal of metal impurity stains. Furthermore, this cleaning solution intentionally contains a specific amount of metal impurities. This further enhances the removal effect of impurity stains on various objects, and significantly enhances the removal effect of metal impurity stains in particular.

[0055] (Second Aspect: Cleaning Method) One embodiment of the cleaning method is a method for cleaning an object to be cleaned by bringing the above-described cleaning liquid into contact with the object to be cleaned. Examples of objects to be cleaned in the cleaning method of this embodiment include membranes; piping in a production line, containers and tools used, etc. For example, the object to be cleaned may be a membrane such as a flat membrane, a hollow fiber membrane, a tubular membrane, a spiral membrane, or a thin film. Alternatively, the object to be cleaned may be an object selected from the group consisting of metal piping, resin piping, glass piping, metal joints, resin joints, glass joints, filters, chemical containers, measurement cells, and chromatography columns.

[0056] More specifically, examples of the cleaning operation of contacting the object with the cleaning solution to clean the object include a method of immersing the object in the cleaning solution and a method of spraying the cleaning solution onto the object. The cleaning operation may be performed once or multiple times. Furthermore, the cleaning solution may be heated during the cleaning operation, or the cleaning operation may be performed at room temperature (e.g., 23°C).

[0057] The cleaning method of this embodiment may include a drying step of drying the object cleaned by the above cleaning operation. In the drying step, a known method such as air drying at room temperature, heating the cleaned object in a thermostatic chamber, or vacuum drying can be applied.

[0058] According to the cleaning method of the present embodiment described above, the cleaning liquid described above is used, and therefore the cleaning method is excellent in removing organic impurities or metal impurities from various objects to be cleaned.

[0059] Another embodiment of the cleaning method is a method further comprising, before or after a step of cleaning an object to be cleaned by contacting the object with the above-mentioned cleaning liquid (hereinafter also referred to as "cleaning step A"), a step of cleaning the object to be cleaned by contacting the object with a second cleaning liquid different from the cleaning liquid (hereinafter also referred to as "cleaning step B").

[0060] The cleaning method of the other embodiment may include: (i) a step of cleaning an object to be cleaned by bringing a second cleaning liquid different from the above-mentioned cleaning liquid (referred to as the first cleaning liquid) into contact with the object to be cleaned, and a step of cleaning the object to be cleaned by bringing the first cleaning liquid into contact with the object to be cleaned that has been cleaned with the second cleaning liquid; (ii) a step of cleaning the object to be cleaned by bringing the above-mentioned cleaning liquid (first cleaning liquid) into contact with the object to be cleaned, and a step of cleaning the object to be cleaned by bringing the second cleaning liquid different from the first cleaning liquid into contact with the object to be cleaned that has been cleaned with the first cleaning liquid; (iii) The method may include the steps of bringing a second cleaning liquid different from the above-mentioned cleaning liquid (first cleaning liquid) into contact with the object to be cleaned, bringing the first cleaning liquid into contact with the object that has been cleaned with the second cleaning liquid, and further bringing a third cleaning liquid different from the above-mentioned first cleaning liquid into contact with the object that has been cleaned with the first cleaning liquid, thereby cleaning the object. In (iii), the second cleaning liquid and the third cleaning liquid may be the same or different from each other.

[0061] Cleaning step B: Examples of a method for cleaning an object by bringing a second cleaning liquid, which is different from the cleaning liquid described above, into contact with the object in cleaning step B include methods similar to those used in cleaning step A (e.g., a method of immersing the object in cleaning liquid, a method of spraying the cleaning liquid onto the object), etc. Cleaning step B may be performed only once or multiple times before or after cleaning step A.

[0062] Second cleaning liquid, third cleaning liquid Examples of cleaning liquids (second cleaning liquid, third cleaning liquid) different from the above-mentioned cleaning liquid include cleaning liquids containing a solvent but not a metal-removing agent. Typical examples of the cleaning liquids (second cleaning liquid, third cleaning liquid) include cleaning liquids consisting of only a solvent.

[0063] Examples of the solvent in the cleaning liquid (second cleaning liquid, third cleaning liquid) include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, ether solvents, sulfoxide solvents, and sulfone solvents; and nonpolar solvents such as hydrocarbon solvents, and specific examples thereof include the same solvents as those in the cleaning liquid described above. Among the above, the cleaning liquid (second cleaning liquid, third cleaning liquid) preferably contains an alcohol solvent, more preferably contains an alcohol solvent having 1 to 5 carbon atoms, and further preferably contains 2-propanol (isopropanol).

[0064] As another embodiment of the cleaning method, a method including a cleaning step A and a step of cleaning the object to be cleaned by contacting the object to be cleaned with an alcohol-based solvent (preferably 2-propanol) before or after the cleaning step A is suitable.

[0065] Another embodiment of the cleaning method may further include a drying step of drying the object cleaned in the cleaning step A or the cleaning step B. As the drying step, known methods such as air drying at room temperature, placing the cleaned object in a thermostatic chamber and heating it, and vacuum drying can be applied.

[0066] According to another embodiment of the cleaning method described above, in addition to the above-mentioned cleaning step A, the cleaning method further includes cleaning step B, so that the effect of removing impurities and dirt adhering to the object to be cleaned is more enhanced than in a cleaning method that includes only the above-mentioned cleaning step A.

[0067] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0068] <Preparation of Cleaning Solution> The components shown in Table 1 were mixed to prepare cleaning solutions for each example.

[0069] (Example 1) In the cleaning solution of Example 1, the content of metal impurities after mixing the components was determined to be 1.1 × 10 for a total of 28 metal elements per 100 parts by mass of the solvent and metal remover, as a result of the measurement of the content of metal impurities described below. －９ It was parts by mass.

[0070] (Examples 2 and 3) By adding a standard solution for metal analysis in solvents (manufactured by Agilent Technologies, part number 5190-8715) as mineral oil to the cleaning solution of Example 1, the content of metal impurities was 4.5 × 10 per 100 parts by mass of the total of the solvent and the metal removal agent. －９ The cleaning solution of Example 2, which is parts by mass, and the content of metal impurities, 23.9 × 10 －９ The cleaning solutions of Example 3 were prepared in parts by mass.

[0071] Comparative Examples 1 and 2: OK73 thinner was used as the cleaning solution in Comparative Example 1. The OK73 thinner was a mixed solvent of PGMEA / PGME = 30 / 70 (mass ratio). Isopropanol was used as the cleaning solution in Comparative Example 2. The content of metal impurities in isopropanol was 2.5 × 10 per 100 parts by mass of the total of the solvent and the metal remover. －９ Parts by mass.

[0072]

[0073] The abbreviations in the table represent the following compounds. The values ​​in brackets [ ] in the table indicate the blend amount (parts by mass): GBL: γ-butyrolactone PGME: propylene glycol monomethyl ether PGMEA: propylene glycol monomethyl ether acetate AcAc: acetylacetone LA: lactic acid IPA: isopropanol

[0074] [Calculation of HSP Distance] The Hansen solubility parameters of each component of the cleaning solution were calculated using "Molecular Modeling Pro" software, version 5.1.9 (ChemSW, Fairfield CA, www.chemsw.com). The Hansen solubility parameters of each component are shown below.

[0075] GBL dispersion force term (δ ｄＧＢＬ ) is 18, and the polar term (δ ｐＧＢＬ ) is 16.6, and the hydrogen bond term (δ ｈＧＢＬ The dispersion term of PGME (δ ｄＰＧＭＥ ) is 15.6, and the polar term (δ ｐＰＧＭＥ) is 6.3, and the hydrogen bond term (δ ｈＰＧＭＥ The value of 11.6 was used for the dispersion force term of AcAc (δ ｄＡｃＡｃ ) is 16.1, and the polar term (δ ｐＡｃＡｃ ) is 10, and the hydrogen bond term (δ ｈＡｃＡｃ The dispersion force term (δ) of LA was set to 6.2. ｄＬＡ ) is 17, and the polar term (δ ｐＬＡ ) is 8.3, and the hydrogen bond term (δ ｈＬＡ ) used a value of 28.4.

[0076] The dispersion force term of PGMEA (δ ｄＰＧＭＥＡ ) is 15.6, and the polar term (δ ｐＰＧＭＥＡ ) is 6.3, and the hydrogen bond term (δ ｈＰＧＭＥＡ The dispersion force term of IPA (δ ｄＩＰＡ ) is 16.3, and the polar term (δ ｐＩＰＡ ) is 6.8, and the hydrogen bond term (δ ｈＩＰＡ ) used a value of 6.5.

[0077] The dispersion force term (δ ｄｔ ), polar term (δ ｐｔ ) and the hydrogen bond term (δ ｈｔ ) was calculated as follows: ｄｔ = (δ ｄＧＢＬ ×49+δ ｄＰＧＭＥ ×49+δ ｄＡｃＡｃ ×1+δ ｄＬＡ × 1) / 100 δ ｐｔ = (δ ｐＧＢＬ ×49+δ ｐＰＧＭＥ ×49+δ ｄＡｃＡｃ ×1+δ ｄＬＡ × 1) / 100 δ ｈｔ = (δ ｈＧＢＬ ×49+δ ｈＰＧＭＥ ×49+δ ｄＡｃＡｃ ×1+δ ｄＬＡ ×1) / 100

[0078] The dispersion force term (δ ｄｔ ), polar term (δ ｐｔ ) and the hydrogen bond term (δ ｈｔ ) was calculated as follows: ｄｔ = (δ ｄＰＧＭＥＡ ×30+δ ｄＰＧＭＥ × 70) / 100 δ ｐｔ= (δ ｐＰＧＭＥＡ ×30+δ ｐＰＧＭＥ × 70) / 100 δ ｈｔ = (δ ｈＰＧＭＥＡ ×30+δ ｈＰＧＭＥ ×70) / 100

[0079] The dispersion force term (δ ｄｔ ), polar term (δ ｐｔ ) and the hydrogen bond term (δ ｈｔ ) was calculated as follows: ｄｔ = (δ ｄＩＰＡ ×100) / 100 δ ｐｔ = (δ ｐＩＰＡ ×100) / 100 δ ｈｔ = (δ ｈＩＰＡ ×100) / 100

[0080] Hansen solubility parameters (MPa) of the cleaning solutions of Examples 1 to 3 ０．５ ) and the Hansen solubility parameter of dimethylacetamide (MPa ０．５ The distance (HSP distance) between the dimethylacetamide and the dimethylacetamide was calculated using the following formula (1t): ｄＤＭＡｃ ) is 16.8, and the polar term (δ ｐＤＭＡｃ ) is 11.5, and the hydrogen bond term (δ ｈＤＭＡｃ ) used a value of 9.4.

[0081] HSP distance = {4(δ ｄｔ -δ ｄＤＭＡｃ ) ２ + (δ ｐｔ -δ ｐＤＭＡｃ ) ２ + (δ ｈｔ -δ ｈＤＭＡｃ ) ２} ０．５ ... (1 ton)

[0082] Hansen solubility parameters (MPa) of the cleaning solutions of Comparative Examples 1 and 2 ０．５ ) and the Hansen solubility parameter of dimethylacetamide (MPa ０．５ ) was calculated in the same manner as in Examples 1 to 3 above.

[0083] [Measurement of Metal Impurity Content] The content of metal impurities in the cleaning solution was measured using an inductively coupled plasma mass spectrometer (manufactured by Agilent Technologies, product name: ICP-MS 8900). The measured metal elements were 28 elements: Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr, Mg, Li, V, Mn, Co, Cu, Ge, As, Sr, Zr, Mo, Ag, Cd, Sn, Sb, Ba, W, Au, and Pb, and the total of these elements was taken as the content (mass fraction) of metal impurities in the cleaning solution. Metal impurity stains in the cleaning evaluation described below, i.e., the total metal amount in OK73 thinner, were also measured in the same manner as above.

[0084] <Cleaning Evaluation (1)> The cleaning solution of each example was used on a porous polyethylene film as the object to be cleaned, and the cleaning method was performed as shown below to evaluate the removability of metal impurity stains. The results are shown in Table 2.

[0085] (Comparative Example 1-1) 100 mL of the cleaning solution (OK73 thinner) of Comparative Example 1 was added to a container. ２ A porous polyethylene film of 1000 ppm was placed in the container and immersed for one day. After that, the porous polyethylene film was removed and the total metal content in the OK73 thinner was measured, which was 37.4 ppb.

[0086] (Example 1-1) 100 mL of the cleaning solution of Example 1 was added to a container. ２ A porous polyethylene film was placed in the container and immersed for one day. The cleaning solution was then discarded from the container, and isopropanol (containing 2.5 ppb of metal impurities) was added to rinse the porous polyethylene film. After rinsing, the isopropanol was discarded from the container and replaced with 100 mL of OK73 thinner (the cleaning solution of Comparative Example 1). The porous polyethylene film was then immersed in the OK73 thinner for one day. The porous polyethylene film was then removed, and the total metal content in the OK73 thinner was measured, which was found to be 0.6 ppb.

[0087] (Examples 1-2 and 1-3) The removability of metal impurity stains from objects to be cleaned was evaluated by using the same cleaning method as above, except that the cleaning solution of Example 1 was changed to the cleaning solutions of Examples 2 and 3, respectively. When the cleaning solution of Example 2 was used, the total metal amount in the OK73 thinner was 0.1 ppb. When the cleaning solution of Example 3 was used, the total metal amount in the OK73 thinner was 2.1 ppb.

[0088] (Comparative Example 1-2) 100 mL of the cleaning solution of Comparative Example 2 was added to a container. ２ A porous polyethylene film was placed in the container and immersed for one day. The cleaning solution was then discarded from the container, and isopropanol (containing 2.5 ppb of metal impurities) was added to rinse the porous polyethylene film. After rinsing, the isopropanol was discarded from the container and replaced with 100 mL of OK73 thinner (the cleaning solution of Comparative Example 1). The porous polyethylene film was then immersed in the OK73 thinner for one day. The porous polyethylene film was then removed, and the total metal content in the OK73 thinner was measured, which was found to be 15.7 ppb.

[0089]

[0090] From the results shown in Table 2, when the cleaning solutions of Examples 1 to 3 were used, the total amount of metal was smaller than when the cleaning solutions of Comparative Examples 1 and 2 were used. This confirms that the cleaning solution and cleaning method to which the present invention is applied can significantly improve the effect of removing metal impurity stains from the object to be cleaned.

[0091] <Cleaning Evaluation (2)> The object to be cleaned was a chemical supply line (connected to a 2 nm HDPE filter, piping), and the cleaning solution of each example was used in the cleaning method described below. The removability of impurities and dirt was evaluated using the number of defects on the wafer surface as an index. The results are shown in Table 3.

[0092] (Comparative Example 2-1) An HDPE 2 nm filter (manufactured by Pall Corporation) was connected to the chemical supply line of a resist chemical coating and developing apparatus (Lithius ProZ, manufactured by Tokyo Electron Ltd.), and 3 GAL of the cleaning solution (OK73 thinner) of Comparative Example 1 was passed through. The OK73 thinner that had passed through the HDPE 2 nm filter was applied to a 12-inch wafer and baked at 80°C for 60 seconds. Thereafter, the number of defects of 17 nm or larger in size was measured using a wafer surface defect measurement apparatus (Surf Scan SP5 XP, manufactured by KLA Tencor). The number of defects when only OK73 thinner was passed through was 584.

[0093] Example 2-1: An HDPE 2 nm filter (manufactured by Pall Corporation) was connected to the chemical supply line of a resist chemical coating and developing apparatus (Lithius ProZ, manufactured by Tokyo Electron Limited). After passing 1 GAL of the cleaning solution from Example 1, the filter was subsequently switched to OK73 thinner and passed 2 GAL. The OK73 thinner that had passed through the HDPE 2 nm filter was applied to a 12-inch wafer and baked at 80°C for 60 seconds. The number of defects of 17 nm or larger in size was then measured using the wafer surface defect detection apparatus. The number of defects was reduced from 359 when only OK73 thinner was passed through the filter to 44.

[0094] (Example 2-2) The cleaning solution of Example 1 was replaced with the cleaning solution of Example 2 and passed through the chemical supply line. After immersion in the chemical supply line for one day, 1 L of the cleaning solution of Example 2 was passed through, and then the solution was switched to OK73 thinner and 1 L was passed through. The OK73 thinner that had been passed through was applied to a 12-inch wafer and baked at 80°C for 60 seconds. Thereafter, the number of defects of 17 nm or larger was measured using the wafer surface defect detection device, and the number of defects was reduced to 53.

[0095] (Examples 2-3) The cleaning solution of Example 1 was replaced with the cleaning solution of Example 3 and passed through the chemical supply line. After immersion in the chemical supply line for one day, 1 L of the cleaning solution of Example 3 was passed through, and then the solution was switched to OK73 thinner and 1 L was passed through. The OK73 thinner that had been passed through was applied to a 12-inch wafer and baked at 80°C for 60 seconds. Thereafter, the number of defects of 17 nm or larger was measured using the wafer surface defect detection device, and the number of defects was reduced to 47.

[0096]

[0097] The results shown in Table 3 show that when the cleaning solutions of Examples 1 to 3 were used, the number of defects on the wafer surface was reduced compared to when only the cleaning solution of Comparative Example 1 was used. This confirms that the application of the present invention can enhance the effect of removing impurities and dirt from the object to be cleaned.

[0098] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible within the scope of the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the appended claims.

Claims

1. A cleaning solution containing a solvent and a metal remover, comprising two or more solvents, the distance (HSP distance) between the Hansen solubility parameter of the cleaning solution and the Hansen solubility parameter of dimethylacetamide is 1.0 or less, and the content of metal impurities is 0.1 x 10 per 100 parts by mass of the total of the solvent and the metal remover. －９ Mass part or more 10 ２ ×10 －６ parts by weight or less of a cleaning solution.

2. The cleaning solution according to claim 1, wherein the metal impurities include at least one metal element selected from the group consisting of Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr and Mg.

3. The cleaning solution according to claim 1, wherein the distance (HSP distance) is 0.5 or less.

4. The cleaning solution according to claim 1, comprising two or more types of said metal removers.

5. The cleaning solution of claim 1, wherein the metal remover comprises an organic acid.

6. The cleaning solution of claim 5, wherein the organic acid is a carboxylic acid.

7. The cleaning solution according to claim 1, which is used for cleaning an object to be cleaned selected from the group consisting of metal piping, resin piping, glass piping, metal joints, resin joints, glass joints, filters, chemical containers, measurement cells, and chromatography columns.

8. A cleaning method comprising contacting an object with the cleaning solution according to any one of claims 1 to 7, thereby cleaning the object.

9. The cleaning method according to claim 8, wherein the object to be cleaned is selected from the group consisting of metal piping, resin piping, glass piping, metal joints, resin joints, glass joints, filters, chemical containers, measurement cells, and chromatography columns.

10. The cleaning method according to claim 8, comprising the step of cleaning the object by contacting the cleaning liquid according to any one of claims 1 to 7 with the object, before or after the step of cleaning the object by contacting the object with a second cleaning liquid different from the cleaning liquid.

11. The cleaning method according to claim 10, wherein the second cleaning liquid contains an alcohol-based solvent.

Images