Cleaning liquid and cleaning method

Abstract

The present invention employs a cleaning liquid containing a solvent and a metal remover. The cleaning liquid contains two or more kinds of solvents, a distance (HSP distance) between a Hansen solubility parameter of the cleaning liquid and a Hansen solubility parameter of dimethylacetamide is 1.0 or less, and a total content of an organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body is 0.1 × 10-9 parts by mass or greater and 105 × 10-6 parts by mass or less with respect to 100 parts by mass of a total amount of the solvents and the metal remover. According to such a cleaning liquid, removability of organic impurity stains is enhanced.

Description

TECHNICAL FIELD

[0001] The present invention relates to a cleaning liquid and a cleaning method.

[0002] Priority is claimed on Japanese Patent Application No. 2023-187034, filed October 31, 2023, the content of which is incorporated herein by reference.BACKGROUND ART

[0003] A cleaning liquid is required to be selected according to the type of stain and the material of a cleaning target.

[0004] In the industrial field, for example, in a film to be produced from a high-molecular-weight material, particularly a porous film, the influence of organic impurity stains such as high-molecular-weight residues derived from the high-molecular-weight material forming members used in a film production step or metal impurity stains derived from a metal catalyst and the like is a problem.

[0005] In dealing with this problem, a film cleaning liquid in which a specific solvent is selected according to the material of the film has been proposed (see Patent Document 1).Citation ListPatent Document

[0006] Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 2017-202479SUMMARY OF INVENTIONTechnical Problem

[0007] In the related art, in a filter to be produced from a porous film, a chemical liquid purified by the filter may be contaminated unintentionally. The contamination source is a high-molecular-weight or low-molecular-weight organic impurity or a metal impurity, which coexists in the filter. Among these, the organic impurities are not only derived from a high-molecular-weight material that forms a member, but are also easily mixed from various places such as each pipe in a production line, a container to be used, and an instrument. On the other hand, with the miniaturization and high performance of industrial products, there is a strong demand for further reduction of the organic impurity stains as described above.

[0008] The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a cleaning liquid having improved removability of organic impurity stains, and a cleaning method using the cleaning liquid. Solution to Problem

[0009] In order to solve the above-described problems, the present invention employs the following configurations.

[0010] According to a first aspect of the present invention, there is provided a cleaning liquid containing: a solvent and a metal remover, in which the cleaning liquid contains two or more kinds of solvents, a distance (HSP distance) between a Hansen solubility parameter of the cleaning liquid and a Hansen solubility parameter of dimethylacetamide is 1.0 or less, and a total content of an organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body is 0.1 × 10 -9< parts by mass or greater and 10 5< × 10 -6< parts by mass or less with respect to 100 parts by mass of a total amount of the solvents and the metal remover.

[0011] According to a second aspect of the present invention, there is provided a cleaning method including cleaning a cleaning target by bringing the cleaning liquid according to the first aspect into contact with the cleaning target.Advantageous Effects of Invention

[0012] According to the present invention, it is possible to provide a cleaning liquid having improved removability of organic impurity stains, and a cleaning method using the cleaning liquid.

[0013] Such a cleaning liquid and a cleaning method using the cleaning liquid are useful for removing organic impurity stains from various cleaning targets.DESCRIPTION OF EMBODIMENTS(First aspect: cleaning liquid)

[0014] According to an embodiment, a cleaning liquid contains two or more kinds of solvents and a metal remover.

[0015] In the present embodiment, a distance (HSP distance) between a Hansen solubility parameter of the cleaning liquid and a Hansen solubility parameter of dimethylacetamide is 1.0 or less.

[0016] In addition, in the cleaning liquid of the present embodiment, a total content of an organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body is 0.1 × 10 -9< parts by mass or greater and 10 5< × 10 -6< parts by mass or less with respect to 100 parts by mass of a total amount of the solvents and the metal remover.<Solvent>

[0017] The cleaning liquid of the present embodiment contains two or more kinds of solvents.

[0018] The solvents contained in the cleaning liquid of the present embodiment can be appropriately selected from known organic solvents such that the HSP distance is 1.0 or less. Examples of the organic solvents include polar solvents such as a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, a nitrile-based solvent, an amide-based solvent, an ether-based solvent, a sulfoxide-based solvent, and a sulfone-based solvent, and non-polar solvents such as a hydrocarbon-based solvent.

[0019] Among the organic solvents, organic solvents containing a plurality of kinds of functional groups that characterize each of the above-described solvents in the structure thereof are also present, but in this case, the organic solvent is considered to correspond to any solvent species containing the functional group of the organic solvent, as described below. For example, diethylene glycol monomethyl ether is considered to correspond to both the alcohol-based solvent and the ether-based solvent in the above-described classification.<<Ketone-based solvent>>

[0020] The ketone-based solvent is an organic solvent containing C-C(=O)-C in the structure thereof.

[0021] Specific examples of the ketone-based solvent 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).

[0022] In addition, the ketone-based solvent may be a cyclic ketone-based solvent. Specific examples of the cyclic ketone-based solvent include cyclohexanone (CH), methylcyclohexanone, isophorone, propylene carbonate, ethylene carbonate, and dihydrolevoglucosenone (Cyrene).<<Ester-based solvent>>

[0023] The ester-based solvent is an organic solvent containing C-C(=O)-O-C in the structure thereof.

[0024] Specific examples of the ester-based solvent include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, 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 carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, and propyl-3-methoxypropionate.

[0025] In addition, the ester-based solvent may be a cyclic ester-based solvent (lactone-based solvent). Specific examples of the lactone-based solvent include γ-butyrolactone (GBL), ε-caprolactone, γ-valerolactone, and δ-valerolactone.<<Alcohol-based solvent>>

[0026] The alcohol-based solvent is an organic solvent containing an alcoholic hydroxy group in the structure thereof.

[0027] The term "alcoholic hydroxy group" denotes a hydroxy group bonded to a carbon atom of an aliphatic hydrocarbon group.

[0028] Specific examples of the alcohol-based solvent 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.<<Nitrile-based solvent>>

[0029] The nitrile-based solvent is an organic solvent containing a nitrile group in the structure thereof.

[0030] Specific examples of the nitrile-based solvent include acetonitrile, propionitrile, valeronitrile, and butyronitrile.<<Amide-based solvent>>

[0031] The amide-based solvent is an organic solvent containing an amide group in the structure thereof.

[0032] Specific examples of the amide-based solvent include chain-like amide-based solvents such as dimethylacetamide (DMAc), dimethylformamide, and tetramethylurea, and cyclic amide (lactam)-based solvents such as dimethylimidazolidinone, N-methylpyrrolidone, 1-ethyl-2-pyrrolidone, and 1-butyl-2-pyrrolidone.<<Ether-based solvent>>

[0033] The ether-based solvent is an organic solvent containing C-O-C in the structure thereof.

[0034] Specific examples of the ether-based solvent 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.<<Sulfoxide-based solvent>>

[0035] The sulfoxide-based solvent is an organic solvent containing a sulfinyl group - S(=O)- in the structure thereof.

[0036] Specific examples of the sulfoxide-based solvent include dimethyl sulfoxide (DMSO).<<Sulfone-based solvent>>

[0037] The sulfone-based solvent is an organic solvent containing a sulfonyl group - S(=O) 2 - in the structure thereof.

[0038] Specific examples of the sulfone-based solvent include sulfolane.<<Hydrocarbon-based solvent>>

[0039] The hydrocarbon-based solvent is a hydrocarbon solvent formed of a hydrocarbon which may be halogenated and having no substituent other than a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom is preferable.

[0040] Specific examples of the hydrocarbon-based solvent include n-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, and n-hexadecane.

[0041] Among the examples, the two or more kinds of solvents in the cleaning liquid according to the present embodiment are preferably a mixed solvent of two or more kinds of solvents selected from the group consisting of a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, and an ether-based solvent, more preferably a mixed solvent of two or more kinds of solvents selected from the group consisting of a ketone-based solvent, an ester-based solvent, and an ether-based solvent, and still more preferably a mixed solvent of two or more kinds of solvents selected from the group consisting of an ester-based solvent and an ether-based solvent.

[0042] Further, in the present specification, the two or more kinds of solvents may be two or more kinds of solvents that contain two kinds of compounds and are classified into the same kind. For example, the two or more kinds of solvents may be a mixed solvent of 1-octanone and cyclohexanone, both of which are classified as ketone-based solvents.<<Metal remover>>

[0043] Examples of the metal remover contained in the cleaning liquid according to the present embodiment include a metal chelating agent and an organic acid.<<Metal chelating agent>>

[0044] Examples of the metal chelating agent in the present embodiment include an amino carboxylic acid-based chelating agent such as ethylenediaminetetraacetic acid, nitrilotriacetic acid, or diethylenetriaminepentaacetic acid, a phosphonic acid-based chelating agent such as 1-hydroxyethane-1,1-diphosphonic acid or nitrilotris(methylenephosphonic acid), and a compound (A1) represented by General Formula (a-1) (hereinafter, also simply referred to as "compound (A1)"). Among these, the compound (A1) is preferable as the metal chelating agent. [In the formula, Ra 1< and Ra 2< each independently represent an alkyl group having 1 to 3 carbon atoms. Ra 3< and Ra 4< each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Ya 1< and Ya 2< each independently represent a single bond, -O-, -S-, or -N(Ra 5< )-. Ra 5< represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. n represents an integer of 0 to 3.]

[0045] In Formula (a-1), examples of the alkyl group having 1 to 3 carbon atoms as Ra 1< to Ra 5< include a methyl group, an ethyl group, a propyl group, and an isopropyl group.

[0046] In Formula (a-1), Ra 1< and Ra 2< each independently represent preferably a methyl group or an ethyl group and more preferably a methyl group.

[0047] It is preferable that Ra 3< and Ra 4< each represent a hydrogen atom.

[0048] Ya 1< represents preferably a single bond or -O- and more preferably a single bond.

[0049] Ya 2< represents preferably a single bond or -O- and more preferably a single bond.

[0050] n represents preferably 1 or 2 and more preferably 1.

[0051] Among the examples, the compound (A1) is preferably acetylacetone (AcAc) or acetonylacetone and more preferably acetylacetone (AcAc).

[0052] In the cleaning liquid according to the present embodiment, the metal chelating agent may be used alone or in combination of two or more kinds thereof.<<Organic acid>>

[0053] Examples of the organic acid in the present embodiment include a carboxylic acid such as lactic acid (LA), citric acid, malic acid, formic acid, acetic acid, oxalic acid, 2-nitrophenylacetic acid, 2-ethylhexanoic acid, or dodecanoic acid, saccharic acid such as ascorbic acid or glucuronic acid, sulfonic acid such as methanesulfonic acid, benzenesulfonic acid, or p-toluenesulfonic acid, phosphoric acid ester such as bis(2-ethylhexyl)phosphoric acid, and phosphoric acid.

[0054] Among the examples, the organic acid is preferably a carboxylic acid, more preferably a hydroxy acid, still more preferably at least one selected from the group consisting of lactic acid, citric acid, and malic acid, and particularly preferably lactic acid.

[0055] In the cleaning liquid according to the present embodiment, the organic acid may be used alone or in combination of two or more kinds thereof.

[0056] It is preferable that the cleaning liquid according to the present embodiment contains two or more kinds of the metal removers.

[0057] The cleaning liquid according to the present embodiment contains preferably two or more kinds of metal removers selected from the group consisting of the above-described metal chelating agent and the above-described organic acid, more preferably two or more kinds of metal removers selected from the group consisting of the above-described compound (A1) and the above-described organic acid, and still more preferably two or more kinds of metal removers selected from the group consisting of the above-described compound (A1) and the above-described carboxylic acid.

[0058] In the cleaning liquid according to the present embodiment, among the examples, it is preferable to use the above-described metal chelating agent and the above-described organic acid in combination, more preferable to use the above-described compound (A1) and the above-described organic acid in combination, and still more preferable to use the above-described compound (A1) and the above-described carboxylic acid in combination.<Optional components>

[0059] The cleaning liquid according to the present embodiment may contain optional components other than the above-described solvent and the above-described metal remover within a range where the effects of the present invention are not impaired.

[0060] Examples of the optional components include a pH adjuster and a surfactant.[Distance between Hansen solubility parameters (HSP distance)]

[0061] The cleaning liquid according to the present embodiment contains the above-described two or more kinds of solvents and metal removers, and the distance (HSP distance) between the Hansen solubility parameter of the cleaning liquid 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.

[0062] In a case where the HSP distance of the cleaning liquid according to the present embodiment is less than or equal to the above-described upper limits, the effect of removing organic impurity stains of the cleaning liquid is enhanced regardless of the material of the cleaning target. The HSP distance of the cleaning liquid according to the present embodiment is preferably as low as possible from the viewpoint of enhancing the effect of removing organic impurity stains of the cleaning liquid.

[0063] The term "Hansen solubility parameter" in the present specification is a numerical constant that is theoretically calculated and is a useful tool for predicting the ability of a solvent material to dissolve a specific solute.

[0064] The Hansen solubility parameter can be used as a measure of the overall strength and selectivity of a material by combining the following three Hansen solubility parameters (δ d (dispersion force term), δ p (polar term), and δ h (hydrogen bond term)) that are experimentally and theoretically derived. The Hansen solubility parameter is in units of MPa 0.5< or (J / cc) 0.5< . δ d : energy derived from dispersion force between molecules δ p : energy derived from polar force between molecules δ h : energy derived from hydrogen bond force between molecules

[0065] The "Hansen solubility parameter" can be calculated, for example, by Hansen Solubility from "Molecular Modeling Pro" software, version 5.1.9 (ChemSW, Fairfield CA, www.chemsw.com) or Dynacomp Software.

[0066] Since the cleaning liquid according to the present embodiment is a mixture, the Hansen solubility parameter of the cleaning liquid according to the present embodiment can be determined as follows.

[0067] For example, in a case where a cleaning liquid CS formed of a solvent S 1< (δ ds1 , δ ps1 , δ hs1 ), a solvent S 2< (δ ds2 , δ ps2 , δ hs2 ), a metal remover B 1< (δ dB1 , δ pB1 , δ hB1 ), and a metal remover B 2< (δ dB2 , δ pB2 , δ hB2 ) has a blending amount of the solvent S 1< of a, a blending amount of the solvent S 2< of b, a blending amount of the metal remover B 1< of c, and a blending amount of the metal remover B 2< of d, δ dcs (dispersion force term), δ pcs (polar term), and δ hcs (hydrogen bond term) of the cleaning liquid CS are calculated by the following equations. It is noted that a + b + c + d = 100. δ dcs = δ ds 1 × a + δ ds 2 × b + δ dB 1 × c + δ dB 2 × d / 100 δ pcs = δ ps 1 × a + δ ps 2 × b + δ pB 1 × c + δ pB 2 × d / 100 δ hcs = δ hs 1 × a + δ hs 2 × b + δ hB 1 × c + δ hB 2 × d / 100

[0068] The distance (HSP distance) between the Hansen solubility parameter of the cleaning liquid CS (cleaning liquid according to the present embodiment) and the Hansen solubility parameter of dimethylacetamide (DMAc) is calculated by Equation (1). HSP distance = 4 δ dcs - δ dDMAc 2 + δ pcs - δ pDMAc 2 + δ hcs - δ hDMAc 2 0.5

[0069] Further, a value of 16.8 is used for the dispersion force term (δ dDMAc ) of dimethylacetamide, a value of 11.5 is used for the polar term (δ pDMAc ), and a value of 9.4 is used for the hydrogen bond term (δ hDMAc ).

[0070] Further, since the content of the organic substance (organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body) contained in the cleaning liquid according to the present embodiment is extremely small, the influence on the variation in the HSP distance is small.

[0071] The HSP distance in the cleaning liquid according to the present embodiment can be controlled, for example, by adopting a solvent or a metal remover close to the values of the dispersion force term (δ dDMAc ), the polar term (δ pDMAc ), and the hydrogen bond term (δ hDMAc ) of dimethylacetamide or by selecting a combination of each component.[Total content of organic substance selected from group consisting of organic acid multimer, organic acid ester, and ketone body]

[0072] In the cleaning liquid according to the present embodiment, the total content of the organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body is 0.1 × 10 -9< parts by mass or greater and 10 5< × 10 -6< parts by mass or less, preferably 5 × 10 -9< parts by mass or greater and 5 × 10 -6< parts by mass or less, more preferably 10 × 10 -9< parts by mass or greater and 2.5 × 10 -6< parts by mass or less, and still more preferably 50 × 10 -9< parts by mass or greater and 1 × 10 -6< parts by mass or less with respect to 100 parts by mass of the total amount of the solvents and the metal remover.

[0073] In a case where the total content of the organic substance in the cleaning liquid according to the present embodiment is in the above-described ranges, the effect of removing organic impurity stains of the cleaning liquid is further enhanced regardless of the material of the cleaning target.

[0074] The term "organic substance" contained in the cleaning liquid according to the present embodiment denotes an organic compound selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body.

[0075] Examples of the organic acid multimer include a lactic acid multimer and lactic anhydride. Examples of the organic acid ester include ethyl lactate and 1-methoxy-2-propyl acetate. Examples of the ketone body include 1-methoxy-2-propanone.

[0076] The total mass of the organic substance in the cleaning liquid can be determined by appropriately selecting a known analysis method.

[0077] The total content of the organic substance in the cleaning liquid can be adjusted by controlling the amount of the organic substance contained in the solvent or the metal remover to be blended, or can be adjusted by adding the organic substance separately after mixing the solvent, the metal remover, and the optional components or by separating and removing an excess amount of the organic substance.

[0078] Suitable examples of the cleaning liquid according to the present embodiment include a composition (X) containing a mixed solvent of two or more kinds of solvents selected from the group consisting of a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, and an ether-based solvent, the above-described metal chelating agent, and the above-described organic acid, in which the HSP distance is 1.0 or less, and the total content of the organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body is 0.1 × 10 -9< parts by mass or greater and 10 5< × 10 -6< parts by mass or less with respect to 100 parts by mass of the total amount of the mixed solvent, the metal chelating agent, and the organic acid.

[0079] 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, still more preferably 0.4 or less, and particularly preferably 0.3 or less, and it is preferable that the distance thereof is as small as possible.

[0080] The mixed solvent in the composition (X) is more preferably a mixed solvent of one or more kinds of solvents selected from the group consisting of a ketone-based solvent and an ester-based solvent (hereinafter, also referred to as "solvent S1") and one or more kinds of solvents selected from the group consisting of an alcohol-based solvent and an ether-based solvent (hereinafter, also referred to as "solvent S2"), still 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.

[0081] For example, in a case where the two or more kinds of solvents in the composition (X) are a mixed solvent of the solvent S1 and the solvent S2, the mixing ratio of the solvent S1 to the solvent S2 (solvent S1:solvent S2) is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and still more preferably 40:60 to 60:40 in terms of the mass ratio.

[0082] Examples of a suitable combination of the two or more kinds of solvents in the composition (X) include a mixed solvent of one or more kinds of solvents selected from the group consisting of γ-butyrolactone, ε-caprolactone, and γ-valerolactone and one or more kinds of solvents selected from the group consisting of EGME, PGME, and PGEE, and a mixed solvent of dihydrolevoglucosenone (Cyrene) and PG.

[0083] Among these, as a suitable combination of the two or more kinds of solvents, a mixed solvent of one or more kinds of solvents selected from the group consisting of γ-butyrolactone, ε-caprolactone, and γ-valerolactone and one or more kinds of solvents selected from the group consisting of EGME, PGME, and PGEE is preferable, and a mixed solvent of γ-butyrolactone and PGME is more preferable.

[0084] The metal chelating agent in the composition (X) is preferably a compound (A1) and more preferably acetylacetone (AcAc).

[0085] The organic acid in the composition (X) is preferably a carboxylic acid, more preferably a hydroxy acid, and still more preferably lactic acid.

[0086] The organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body is preferably at least one selected from the group consisting of a lactic acid multimer, lactic anhydride, ethyl lactate, 1-methoxy-2-propyl acetate, and 1-methoxy-2-propanone and more preferably at least one selected from the group consisting of a lactic acid multimer, ethyl lactate, 1-methoxy-2-propyl acetate, and 1-methoxy-2-propanone.

[0087] In the composition (X), the total content of the organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body is 0.1 × 10 -9< parts by mass or greater and 10 5< × 10 -6< parts by mass or less, preferably 5 × 10 -9< parts by mass or greater and 5 × 10 -6< parts by mass or less, more preferably 10 × 10 -9< parts by mass or greater and 2.5 × 10 -6< parts by mass or less, and still more preferably 50 × 10 -9< parts by mass or greater and 1 × 10 -6< parts by mass or less with respect to 100 parts by mass of the total amount of the mixed solvent, the metal chelating agent, and the organic acid.

[0088] The content of each of the mixed solvent, the metal chelating agent, and the organic acid in the composition (X) is appropriately selected such that the HSP distance becomes 1.0 or less.

[0089] The content of the mixed solvent in the composition (X) is preferably 90% to 99.5% by mass and more preferably 95% to 99% by mass with respect to the total amount of the composition (X).

[0090] The content of the metal chelating agent in the composition (X) is preferably 0.1% to 9% by mass, more preferably 0.5% to 9% by mass, and still more preferably 0.5% to 5% by mass with respect to the total amount of the composition (X).

[0091] The proportion of the compound (A1) in the metal chelating agent is preferably 50% by mass or more and more preferably 75% by mass or more, and may be 100% by mass with respect to the total mass of the metal chelating agent.

[0092] 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 still more preferably 0.5% to 5% by mass with respect to 100% by mass of the total amount of the composition (X).

[0093] The proportion of the carboxylic acid in the organic acid is preferably 50% by mass or greater and more preferably 75% by mass or greater, and may be 100% by mass with respect to the total mass of the organic acid.

[0094] The composition (X) may further contain the optional components described above as necessary, in addition to the mixed solvent, the metal chelating agent, and the organic acid.

[0095] The cleaning liquid of the present embodiment is a cleaning liquid useful for cleaning a membrane.

[0096] The form and the shape of the membrane are not particularly limited, and examples thereof include a flat membrane, a hollow fiber membrane, a tubular membrane, a spiral membrane, and a thin membrane (film).

[0097] In addition, the material of the membrane is not particularly limited, and examples thereof include polyolefin (polyethylene, polypropylene, or the like), polysulfone, polyacrylonitrile, polyamide, polyimide, polyvinyl alcohol, a cellulose acetate-based material, a fluoropolymer, and ceramic.

[0098] In addition, the cleaning liquid of the present embodiment is also useful for removing organic impurity stains from various cleaning targets. Examples of the various cleaning targets include each pipe in a production line, a container to be used, and an instrument. For example, the cleaning liquid of the present embodiment can be used for cleaning a cleaning target selected from the group consisting of a metal pipe, a resin pipe, a glass pipe, a metal joint, a resin joint, a glass joint, a filter, a chemical liquid container, a measurement cell, and a chromatography column.

[0099] The cleaning liquid of the present embodiment described above contains two or more kinds of solvents and a metal remover. In addition, the distance (HSP distance) between the Hansen solubility parameter of the cleaning liquid and the Hansen solubility parameter of dimethylacetamide (DMAc) is 1.0 or less, and the total content of the organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body is 0.1 × 10 -9< parts by mass or greater and 10 5< × 10 -6< parts by mass or less with respect to 100 parts by mass of the total of the solvents and the metal remover.

[0100] In such a cleaning liquid, since the Hansen solubility parameter of the entire cleaning liquid is adjusted to be close to that of DMAc, the removability of high-molecular-weight residues derived from a high-molecular-weight material is satisfactory.

[0101] The reason is not clear, but a satisfactory cleaning and removing effect is exhibited even with respect to both a polar cleaning target and a non-polar cleaning target in a case where such a cleaning liquid contains a metal remover while the Hansen solubility parameter of the entire cleaning liquid is adjusted to be close to that of DMAc.

[0102] Further, such a cleaning liquid is intentionally made to contain a specific content of the organic substance. In this manner, the effect of removing organic impurity stains from various cleaning targets is further enhanced.

[0103] In addition, since the cleaning liquid of the present embodiment contains a metal remover, the removability of metal impurity stains is also satisfactory.(Second aspect: cleaning method)

[0104] According to an embodiment, the cleaning method is a method of cleaning a cleaning target by bringing the above-described cleaning liquid into contact with the cleaning target.

[0105] Examples of the cleaning target in the cleaning method of the present embodiment include a membrane, each pipe in a production line, a container to be used, and an instrument. For example, the cleaning target may be a membrane such as a flat membrane, a hollow fiber membrane, a tubular membrane, a spiral membrane, or a thin membrane (film). Alternatively, the cleaning target may be selected from the group consisting of a metal pipe, a resin pipe, a glass pipe, a metal joint, a resin joint, a glass joint, a filter, a chemical liquid container, a measurement cell, and a chromatography column.

[0106] More specific examples of a cleaning operation of cleaning the cleaning target by bringing the above-described cleaning liquid into contact with the cleaning target include a method of immersing a cleaning target in the cleaning liquid and a method of spraying the cleaning liquid onto a cleaning target.

[0107] The cleaning operation may be performed only once or a plurality of times.

[0108] In addition, the cleaning liquid may be heated or the cleaning operation may be performed at room temperature (for example, 23°C) during the cleaning operation.

[0109] The cleaning method of the present embodiment may include a drying step of drying the cleaning target cleaned by the above-described cleaning operation. A known method such as a method of air drying at room temperature, a method of placing the cleaned cleaning target in a constant-temperature tank and heating the cleaning target, or a method of vacuum drying can be applied in the drying step.

[0110] According to the cleaning method of the present embodiment described above, since the above-described cleaning liquid is used, the cleaning method has excellent removability for organic impurity stains from various cleaning targets.

[0111] The cleaning method according to another embodiment is a method further including, before or after a step of cleaning the cleaning target by bringing the above-described cleaning liquid into contact with the cleaning target (hereinafter, also referred to as "cleaning step A"), a step of cleaning the cleaning target by bringing the cleaning target into contact with a second cleaning liquid different from the cleaning liquid (hereinafter, also referred to as "cleaning step B").

[0112] The cleaning method according to another embodiment described above may include (i) a step of cleaning the cleaning target by bringing the second cleaning liquid different from the above-described cleaning liquid (referred to as a first cleaning liquid) into contact with the cleaning target and a step of cleaning the cleaning target by bringing the first cleaning liquid into contact with the cleaning target cleaned with the second cleaning liquid, (ii) a step of cleaning the cleaning target by bringing the above-described cleaning liquid (first cleaning liquid) into contact with the cleaning target and a step of cleaning the cleaning target by bringing the second cleaning liquid different from the first cleaning liquid into contact with the cleaning target cleaned with the first cleaning liquid, or (iii) a step of cleaning the cleaning target by bringing the second cleaning liquid different from the above-described cleaning liquid (first cleaning liquid) into contact with the cleaning target, a step of cleaning the cleaning target by bringing the first cleaning liquid into contact with the cleaning target cleaned with the second cleaning liquid, and a step of cleaning the cleaning target by bringing a third cleaning liquid different from the first cleaning liquid into contact with the cleaning target cleaned with the first cleaning liquid.

[0113] In the item (iii), the second cleaning liquid and the third cleaning liquid may be the same as or different from each other.· Cleaning step B

[0114] Examples of the method of cleaning the cleaning target by bringing the second cleaning liquid different from the above-described cleaning liquid in the cleaning step B into contact with the cleaning target include the same method as the method in the above-described cleaning step A (a method of immersing the cleaning target in the cleaning liquid, a method of spraying the cleaning liquid onto the cleaning target, or the like).

[0115] The cleaning step B may be performed only once or a plurality of times before or after the cleaning step A.· Second cleaning liquid and third cleaning liquid

[0116] Examples of the cleaning liquid (the second cleaning liquid or the third cleaning liquid) different from the above-described cleaning liquid include a cleaning liquid containing a solvent and no metal remover. Typical examples of the cleaning liquid (the second cleaning liquid or the third cleaning liquid) include a cleaning liquid formed of only a solvent.

[0117] Examples of the solvent in the cleaning liquid (the second cleaning liquid or the third cleaning liquid) include polar solvents such as a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, a nitrile-based solvent, an amide-based solvent, an ether-based solvent, a sulfoxide-based solvent, and a sulfone-based solvent, and non-polar solvents such as a hydrocarbon-based solvent, and specific examples thereof include the same solvents as those in the above-described cleaning liquid.

[0118] Among these, the cleaning liquid (the second cleaning liquid or the third cleaning liquid) contains preferably an alcohol-based solvent, more preferably an alcohol-based solvent having 1 to 5 carbon atoms, and still more preferably 2-propanol (isopropanol).

[0119] According to another embodiment of the cleaning method, a method including the cleaning step A and a step of cleaning the cleaning target by bringing the cleaning target into contact with an alcohol-based solvent (preferably 2-propanol) before or after the cleaning step A is suitable.

[0120] According to another embodiment, the cleaning method may further include a drying step of drying the cleaning target cleaned in the cleaning step A or the cleaning step B.

[0121] A known method such as a method of air drying at room temperature, a method of placing the cleaned cleaning target in a constant-temperature tank and heating the cleaning target, or a method of vacuum drying can be applied in the drying step.

[0122] According to another embodiment of the cleaning method described above, since the cleaning method further includes the cleaning step B in addition to the cleaning step A described above, the effect of removing organic impurity stains adhering to the cleaning target is further enhanced as compared with the cleaning method including only the cleaning step A described above.Examples

[0123] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.<Preparation of cleaning liquid>

[0124] Each component was mixed according to the compositional ratio listed in Table 1 to prepare a cleaning liquid of each example. [Table 1]Cleaning liquidSolventMetal removerHSP distanceType of organic substance and proportion (parts by mass) of organic substance in 100 parts by mass of total amount of solvent and metal removerReference Example 1GBL

[49] PGME

[49] AcAc [1]LA [1]0.27-0Example 1GBL

[49] PGME

[49] AcAc [1]LA [0.8]0.27Lactic acid multimer2 × 10 -9< Example 2GBL

[49] PGME

[49] AcAc [1]LA [1]0.27Ethyl lactate1 × 10 -6< Example 3GBL

[49] PGME

[49] AcAc [1]LA [1]0.27Ethyl lactate10 3< × 10 -6< Example 4GBL

[49] PGME

[49] AcAc [1]LA [1]0.271-Methoxy-2-propyl acetate1 × 10 -6< Example 5GBL

[49] PGME

[49] AcAc [1]LA [1]0.271-Methoxy-2-propyl acetate10 3< × 10 -6< Example 6GBL

[49] PGME

[49] AcAc [1]LA [1]0.271-Methoxy-2-propanone1 × 10 -6< Example 7GBL

[49] PGME

[49] AcAc [1]LA [1]0.271-Methoxy-2-propanone10 3< × 10 -6< Comparative Example 1BA

[100] ---8.19-0Comparative Example 2PGMEA

[30] PGME

[70] --5.54-0Comparative Example 3PGMEA

[55] DMSO

[45] --7.04-0

[0125] The abbreviations in the table represent the following compounds. The numerical values in the parentheses in the table are blending amounts (parts by mass). GBL: γ-butyrolactone PGME: propylene glycol monomethyl ether PGMEA: propylene glycol monomethyl ether acetate AcAc: acetylacetone LA: lactic acid BA: n-butyl acetate DMSO: dimethyl sulfoxide (Reference Example 1)

[0126] 1 part by mass of lactic acid (LA) was added to 49 parts by mass of γ-butyrolactone (GBL), 49 parts by mass of propylene glycol monomethyl ether (PGME), and 1 part by mass of acetylacetone (AcAc) to prepare a cleaning liquid of Reference Example 1.(Example 1)

[0127] A cleaning liquid of Example 1 was prepared in the same manner as in Reference Example 1 except that lactic acid containing a lactic acid multimer and having a purity of 80% was used instead of the lactic acid (LA).

[0128] The identification and quantification of the lactic acid multimer were measured by gel permeation chromatography (GPC). The content of the lactic acid multimer was 2 × 10 -9< parts by mass with respect to 100 parts by mass of the total amount of the solvent and the metal remover.(Example 2)

[0129] A cleaning liquid of Example 2 was prepared by adding ethyl lactate to the cleaning liquid of Reference Example 1. In this case, the content of ethyl lactate was set to 1 × 10 -6< parts by mass with respect to 100 parts by mass of the total amount of the solvent and the metal remover.(Example 3)

[0130] A cleaning liquid of Example 3 was prepared by adding ethyl lactate to the cleaning liquid of Reference Example 1. In this case, the content of ethyl lactate was set to 10 3< × 10 -6< parts by mass with respect to 100 parts by mass of the total amount of the solvent and the metal remover.(Example 4)

[0131] A cleaning liquid of Example 4 was prepared by adding 1-methoxy-2-propyl acetate to the cleaning liquid of Reference Example 1. In this case, the content of 1-methoxy-2-propyl acetate was set to 1 × 10 -6< parts by mass with respect to 100 parts by mass of the total amount of the solvent and the metal remover.(Example 5)

[0132] A cleaning liquid of Example 5 was prepared by adding 1-methoxy-2-propyl acetate to the cleaning liquid of Reference Example 1. In this case, the content of 1-methoxy-2-propyl acetate was set to 10 3< × 10 -6< parts by mass with respect to 100 parts by mass of the total amount of the solvent and the metal remover.(Example 6)

[0133] A cleaning liquid of Example 6 was prepared by adding 1-methoxy-2-propanone to the cleaning liquid of Reference Example 1. In this case, the content of 1-methoxy-2-propanone was set to 1 × 10 -6< parts by mass with respect to 100 parts by mass of the total amount of the solvent and the metal remover.(Example 7)

[0134] A cleaning liquid of Example 7 was prepared by adding 1-methoxy-2-propanone to the cleaning liquid of Reference Example 1. In this case, the content of 1-methoxy-2-propanone was set to 10 3< × 10 -6< parts by mass with respect to 100 parts by mass of the total amount of the solvent and the metal remover.(Comparative Example 1)

[0135] n-Butyl acetate was used as a cleaning liquid of Comparative Example 1.(Comparative Example 2)

[0136] OK73 thinner was used as a cleaning liquid of Comparative Example 2. The composition of the OK73 thinner was a mixed solvent of PGMEA and PGME at a mass ratio of 30:70.(Comparative Example 3)

[0137] A mixed solvent of PGMEA / DMSO = 55 / 45 (mass ratio) was used as a cleaning liquid of Comparative Example 3.[Calculation of HSP distance]

[0138] The Hansen solubility parameter of each component of the cleaning liquid was calculated using "Molecular Modeling Pro" software, version 5.1.9 (ChemSW, Fairfield CA, www.chemsw.com). The Hansen solubility parameter of each component is shown below.

[0139] A value of 18 was used as the dispersion force term (δ dGBL ) of GBL, a value of 16.6 was used as the polar term (δ pGBL ) of GBL, and a value of 7.4 was used as the hydrogen bond term (δ hGBL ) of GBL.

[0140] A value of 15.6 was used as the dispersion force term (δ dPGME ) of PGME, a value of 6.3 was used as the polar term (δ pPGME ) of PGME, and a value of 11.6 was used as the hydrogen bond term (δ hPGME ) of PGME.

[0141] A value of 16.1 was used as the dispersion force term (δ dAcAc ) of AcAc, a value of 10 was used as the polar term (δ pAcAc ) of AcAc, and a value of 6.2 was used as the hydrogen bond term (δ hAcAc ) of AcAc.

[0142] A value of 17 was used as the dispersion force term (δ dLA ) of LA, a value of 8.3 was used as the polar term (δ pLA ) of LA, and a value of 28.4 was used as the hydrogen bond term (δ hLA ) of LA.

[0143] A value of 15.6 was used as the dispersion force term (δ dPGMEA ) of PGMEA, a value of 6.3 was used as the polar term (δ pPGMEA ) of PGMEA, and a value of 7.7 was used as the hydrogen bond term (δ hPGMEA ) of PGMEA.

[0144] A value of 15.6 was used as the dispersion force term (δ dBA ) of BA, a value of 3.7 was used as the polar term (δ pBA ) of BA, and a value of 6.3 was used as the hydrogen bond term (δ hBA ) of BA.

[0145] A value of 18.4 was used as the dispersion force term (δ dDMSO ) of DMSO, a value of 16.4 was used as the polar term (δ pDMSO ) of DMSO, and a value of 10.2 was used as the hydrogen bond term (δ hDMSO ) of DMSO.

[0146] The dispersion force terms (δ dt ), the polar terms (δ pt ), and the hydrogen bond terms (δ ht ) of the cleaning liquids of Reference Example 1 and Examples 1 to 7 were determined as follows. δ 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

[0147] The dispersion force term (δ dt ), the polar term (δ pt ), and the hydrogen bond term (δ ht ) of the cleaning liquid of Comparative Example 1 were determined as follows. δ dt = δ dBA × 100 / 100 δ pt = δ pBA × 100 / 100 δ ht = δ hBA × 100 / 100

[0148] The dispersion force term (δ dt ), the polar term (δ pt ), and the hydrogen bond term (δ ht ) of the cleaning liquid of Comparative Example 2 were determined as follows. δ 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

[0149] The dispersion force term (δ dt ), the polar term (δ pt ), and the hydrogen bond term (δ ht ) of the cleaning liquid of Comparative Example 3 were determined as follows. δ dt = δ dPGMEA × 55 + δ dDMSO × 45 / 100 δ pt = δ pPGMEA × 55 + δ pDMSO × 45 / 100 δ ht = δ hPGMEA × 55 + δ hDMSO × 45 / 100

[0150] In Reference Example 1 and Examples 1 to 7, the distance (HSP distance) between the Hansen solubility parameter (MPa 0.5< ) of the cleaning liquid and the Hansen solubility parameter (MPa 0.5< ) of dimethylacetamide was calculated according to Equation (1t).

[0151] A value of 16.8 was used as the dispersion force term (δ dDMAc ) of dimethylacetamide, a value of 11.5 was used as the polar term (δ pDMAc ), and a value of 9.4 was used as the hydrogen bond term (δ hDMAc ). HSP distance = 4 δ dt − δ dDMAc 2 + δ pt − δ pDMAc 2 + δ ht − δ hDMAc 2 0.5

[0152] In Comparative Examples 1 to 3, the distance (HSP distance) between the Hansen solubility parameter of the cleaning liquid and the Hansen solubility parameter of dimethylacetamide was also calculated in the same manner as in Reference Example 1 and Examples 1 to 7.<Cleaning evaluation (1)>

[0153] Non-volatile residues (NVRs) were measured by using the cleaning liquid of each example for each of a polyethylene-based porous membrane (PE film) and a polyimide-based porous membrane (PI film) as the cleaning target and using the cleaning method as described below. Next, the removability of the organic impurity stains was evaluated from the measurement results.

[0154] A porous polyethylene film with a size of 1000 cm 2< was used as the PE film.

[0155] A porous polyimide film with a size of 1000 cm 2< was used as the PI film.(Reference Example 1-1, Examples 1-1 to 1-7, and Comparative Examples 1-1 to 1-3)

[0156] 100 mL of the cleaning liquids of Reference Example 1, Examples 1 to 7, and Comparative Examples 1 to 3 was added to each container.

[0157] The porous polyethylene film with a size of 1000 cm 2< was placed and immersed in 100 mL of the cleaning liquid of each example for 1 day. Separately, the porous polyimide film with a size of 1000 cm 2< was placed and immersed in 100 mL of the cleaning liquid of each example for 1 day.

[0158] Thereafter, the cleaning liquid was discarded from each container, and isopropanol was added thereto, and the porous polyethylene film and the porous polyimide film were rinsed.

[0159] After the rinsing, the porous polyethylene film and the porous polyimide film were vacuum-dried overnight.

[0160] Each dried film was immersed in isopropanol, each film was taken out, the remaining isopropanol was transferred to a platinum dish and evaporated, and the weight of the platinum dish was measured. The mass of the non-volatile residues (NVR) was measured from the weight difference between the platinum dish before the experiment and the platinum dish after the experiment.

[0161] The removability of the organic impurity stains was evaluated using a value (hereinafter, referred to as a "residue removal rate") obtained by dividing the mass of the NVR of the film after the immersion cleaning treatment with the cleaning liquid by the mass of the NVR of the film before the cleaning (treatment after rinsing with isopropanol) as an index.

[0162] Table 2 lists the residue removal rate as "PE NVR" in a case where the PE film was used as the cleaning target and the residue removal rate as "PI NVR" in a case where the PI film was used as the cleaning target.

[0163] As the value of the residue removal rate decreases, the removal effect of the cleaning liquid on the organic impurity stains of each film increases. [Table 2]Residue removal ratePE NVRPI NVRReference Example 1-10.070.05Example 1-10.150.10Example 1-20.150.17Example 1-30.110.14Example 1-40.140.12Example 1-50.090.13Example 1-60.140.17Example 1-70.260.28Comparative Example 1-10.100.88Comparative Example 1-20.010.49Comparative Example 1-30.150.45

[0164] As shown in the results listed in Table 2, it can be confirmed that in a case where the cleaning liquids of Examples 1 to 7 were used, the value of the residue removal rate in a case where the PI film was used as the cleaning target was smaller than that in a case where the cleaning liquids of Comparative Examples 1 to 3 were used. Therefore, it can be confirmed that, according to the cleaning liquid to which the present invention was applied, the removability of the organic impurity stains of the porous polyimide film was enhanced.

[0165] It was confirmed that the cleaning liquids of Examples 1 to 7 were obtained by further adding a specific amount of the organic substance to the composition of the cleaning liquid of Reference Example 1, and had satisfactory cleaning performance similarly to the cleaning liquid of Reference Example 1.<Cleaning evaluation (2)>

[0166] The removability of the organic impurity stains was evaluated based on the number of defects on the wafer surface as an index by the cleaning method described below using the cleaning liquid of each example with respect to a chemical liquid supply line (pipe after passage of the BARC chemical liquid) serving as a cleaning target. The results thereof are listed in Table 3.(Reference Example 2-1)

[0167] A chemical liquid bottle of an antireflection coating (BARC) chemical liquid (novolac-based resin, solvent PGEE; ARC-212, manufactured by Brewer Science, Inc.) was connected to a chemical liquid supply line of a resist chemical liquid coating and developing device (Lithius ProZ, manufactured by Tokyo Electron Limited), and the chemical liquid was allowed to pass through the chemical liquid supply line for a certain period of time.

[0168] After the chemical liquid was allowed to pass through the chemical liquid supply line for a certain period of time, the chemical liquid supply line was connected to a chemical liquid bottle of OK73 thinner, OK73 thinner was immersed in the pipe for 1 day, and 3 L of OK73 thinner was allowed to pass through the pipe.

[0169] A 12-inch wafer was spin-coated with the OK73 thinner allowed to pass through the pipe and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by a wafer surface defect device (Surf Scan SP5 XP, manufactured by KLA Tencor), and the number of defects was 33099. Further, the number of defects of the PGME thinner before the pipe connection (cleanliness of PGME) was 550.

[0170] Thereafter, the chemical liquid supply line was connected to the cleaning liquid of Reference Example 1, the chemical liquid supply line was immersed in the pipe for 1 day, and 1 L of the cleaning liquid of Reference Example 1 was allowed to pass through the pipe. Thereafter, the cleaning liquid was switched to OK73 thinner, 1 L of OK73 thinner was allowed to pass through the pipe, a 12-inch wafer was spin-coated with the OK73 thinner and subjected to a baking treatment at 80°C for 60 seconds, and the number of defects having a size of 17 nm or greater was reduced to 876 in a case of measurement with the wafer surface defect device.(Example 2-1)

[0171] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 1, the cleaning liquid of Example 1 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 1 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0172] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 912.(Example 2-2)

[0173] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 2, the cleaning liquid of Example 2 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 2 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0174] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 866.(Example 2-3)

[0175] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 3, the cleaning liquid of Example 3 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 3 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0176] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 934.(Example 2-4)

[0177] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 4, the cleaning liquid of Example 4 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 4 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0178] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 884.(Example 2-5)

[0179] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 5, the cleaning liquid of Example 5 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 5 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0180] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 871.(Example 2-6)

[0181] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 6, the cleaning liquid of Example 6 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 6 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0182] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 962.(Example 2-7)

[0183] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 7, the cleaning liquid of Example 7 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 7 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0184] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 837.(Comparative Example 2-1)

[0185] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Comparative Example 1, the cleaning liquid of Comparative Example 1 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Comparative Example 1 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0186] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 35621.(Comparative Example 2-2)

[0187] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Comparative Example 2, the cleaning liquid of Comparative Example 2 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Comparative Example 2 was allowed to pass through the pipe, and switched to the OK73 thinner different from the cleaning liquid of Comparative Example 2, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0188] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 32804.(Comparative Example 2-3)

[0189] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Comparative Example 3, the cleaning liquid of Comparative Example 3 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Comparative Example 3 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0190] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 17 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 34152. [Table 3]Number of defects on wafer surface (pieces)Reference Example 2-1876Example 2-1912Example 2-2866Example 2-3934Example 2-4884Example 2-5871Example 2-6962Example 2-7837Comparative Example 2-135621Comparative Example 2-232804Comparative Example 2-334152

[0191] As shown in the results listed in Table 3, in a case where the cleaning liquids of Examples 1 to 7 were used, the number of defects on the wafer surface was greatly reduced as compared with a case where the cleaning liquids of Comparative Examples 1 to 3 were used. Therefore, it was confirmed that, according to the cleaning liquid to which the present invention was applied, the removability of organic impurity stains in the pipe after passage of the BARC chemical liquid was enhanced.

[0192] It was confirmed that even in <Cleaning evaluation (2)>, the cleaning liquids of Examples 1 to 7 were obtained by further adding a specific amount of the organic substance to the composition of the cleaning liquid of Reference Example 1, and had satisfactory cleaning performance similarly to the cleaning liquid of Reference Example 1.<Cleaning evaluation (3)>

[0193] The removability of the organic impurity stains was evaluated based on the number of defects on the wafer surface as an index by the cleaning method described below using the cleaning liquid of each example with respect to a chemical liquid supply line (pipe after passage of a spin-on-glass (SOG) chemical liquid) serving as a cleaning target. The results thereof are listed in Table 4.(Reference Example 3-1)

[0194] A chemical liquid bottle of a SOG chemical liquid (HM-825, manufactured by Shin-Etsu Chemical Co., Ltd.) was connected to a chemical liquid supply line of a resist chemical liquid coating and developing device (Lithius i+, manufactured by Tokyo Electron Limited), and the chemical liquid was allowed to pass through the chemical liquid supply line for a certain period of time.

[0195] After the chemical liquid was allowed to pass through the chemical liquid supply line for a certain period of time, the chemical liquid supply line was connected to a chemical liquid bottle of OK73 thinner, OK73 thinner was immersed in the pipe for 1 day, and 3 L of OK73 thinner was allowed to pass through the pipe.

[0196] A 12-inch wafer was spin-coated with the OK73 thinner allowed to pass through the pipe and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by a wafer surface defect device (Surf Scan SP5 XP, manufactured by KLA Tencor), and the number of defects was 5255. Further, the number of defects of the PGME thinner before the pipe connection (cleanliness of PGME) was 550.

[0197] Thereafter, the chemical liquid supply line was connected to the cleaning liquid of Reference Example 1, the chemical liquid supply line was immersed in the pipe for 1 day, and 1 L of the cleaning liquid of Reference Example 1 was allowed to pass through the pipe. Thereafter, the chemical liquid was switched to OK73 thinner, 1 L of the OK73 thinner was allowed to pass through the pipe, a 12-inch wafer was spin-coated with the OK73 thinner and subjected to a baking treatment at 80°C for 60 seconds, and the number of defects having a size of 19 nm or greater was reduced to 180 in a case of measurement with the wafer surface defect device.(Example 3-1)

[0198] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 1, the cleaning liquid of Example 1 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 1 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0199] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 165.(Example 3-2)

[0200] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 2, the cleaning liquid of Example 2 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 2 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0201] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 172.(Example 3-3)

[0202] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 3, the cleaning liquid of Example 3 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 3 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0203] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 152.(Example 3-4)

[0204] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 4, the cleaning liquid of Example 4 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 4 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0205] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 191.(Example 3-5)

[0206] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 5, the cleaning liquid of Example 5 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 5 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0207] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 150.(Example 3-6)

[0208] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 6, the cleaning liquid of Example 6 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 6 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0209] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 181.(Example 3-7)

[0210] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Example 7, the cleaning liquid of Example 7 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Example 7 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0211] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 123.(Comparative Example 3-1)

[0212] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Comparative Example 1, the cleaning liquid of Comparative Example 1 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Comparative Example 1 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0213] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 4172.(Comparative Example 3-2)

[0214] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Comparative Example 2, the cleaning liquid of Comparative Example 2 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Comparative Example 2 was allowed to pass through the pipe, and switched to the OK73 thinner different from the cleaning liquid of Comparative Example 2, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0215] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 3401.(Comparative Example 3-3)

[0216] The cleaning liquid of Reference Example 1 was changed to the cleaning liquid of Comparative Example 3, the cleaning liquid of Comparative Example 3 was allowed to pass through the pipe of the chemical liquid supply line and immersed therein for 1 day, 1 L of the cleaning liquid of Comparative Example 3 was allowed to pass through the pipe, and switched to the OK73 thinner, and 1 L of the OK73 thinner was allowed to pass through the pipe.

[0217] A 12-inch wafer was spin-coated with the OK73 thinner, which had been allowed to pass through the pipe, and subjected to a baking treatment at 80°C for 60 seconds. Thereafter, the number of defects having a size of 19 nm or greater was measured by the wafer surface defect device, and the number of defects was reduced to 4512. [Table 4]Number of defects on wafer surface (pieces)Reference Example 3-1180Example 3-1165Example 3-2172Example 3-3152Example 3-4191Example 3-5150Example 3-6181Example 3-7123Comparative Example 3-14172Comparative Example 3-23401Comparative Example 3-34512

[0218] As shown in the results listed in Table 4, in a case where the cleaning liquids of Examples 1 to 7 were used, the number of defects on the wafer surface was greatly reduced as compared with a case where the cleaning liquids of Comparative Examples 1 to 3 were used. Therefore, it was confirmed that, according to the cleaning liquid to which the present invention was applied, the removability of organic impurity stains in the pipe after passage of the SOG chemical liquid was enhanced.

[0219] It was confirmed that even in <Cleaning evaluation (3)>, the cleaning liquids of Examples 1 to 7 were obtained by further adding a specific amount of the organic substance to the composition of the cleaning liquid of Reference Example 1, and had satisfactory cleaning performance similarly to the cleaning liquid of Reference Example 1.

[0220] Hereinabove, preferable examples of the present invention have been described, but the present invention is not limited to these examples. Configurations can be added, omitted, and replaced, and other modifications can be made within a range not departing from the gist of the present invention. The present invention is not limited by the description above, but only by the scope of the appended claims.

Claims

1. A cleaning liquid comprising: a solvent; and a metal remover, wherein the cleaning liquid contains two or more kinds of solvents, a distance (HSP distance) between a Hansen solubility parameter of the cleaning liquid and a Hansen solubility parameter of dimethylacetamide is 1.0 or less, and a total content of an organic substance selected from the group consisting of an organic acid multimer, an organic acid ester, and a ketone body is 0.1 × 10-9 parts by mass or greater and 105 × 10-6 parts by mass or less with respect to 100 parts by mass of a total amount of the solvents and the metal remover.

2. The cleaning liquid according to Claim 1, wherein the distance (HSP distance) is 0.5 or less.

3. The cleaning liquid according to Claim 1, wherein the cleaning liquid contains two or more kinds of the metal removers.

4. The cleaning liquid according to Claim 1, wherein the metal remover contains an organic acid.

5. The cleaning liquid according to Claim 4, wherein the organic acid is a carboxylic acid.

6. The cleaning liquid according to Claim 1, wherein the cleaning liquid is used for cleaning a cleaning target selected from the group consisting of a metal pipe, a resin pipe, a glass pipe, a metal joint, a resin joint, a glass joint, a filter, a chemical liquid container, a measurement cell, and a chromatography column.

7. A cleaning method comprising: cleaning a cleaning target by bringing the cleaning liquid according to any one of Claims 1 to 6 into contact with the cleaning target.

8. The cleaning method according to Claim 7, wherein the cleaning target is selected from the group consisting of a metal pipe, a resin pipe, a glass pipe, a metal joint, a resin joint, a glass joint, a filter, a chemical liquid container, a measurement cell, and a chromatography column.

9. The cleaning method according to Claim 7, further comprising: a step of cleaning the cleaning target by bringing the cleaning target into contact with a second cleaning liquid different from the cleaning liquid before or after the step of cleaning the cleaning target by bringing the cleaning liquid according to any one of Claims 1 to 6 into contact with the cleaning target.

10. The cleaning method according to Claim 9, wherein the second cleaning liquid contains an alcohol-based solvent.

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