Processing liquid

Abstract

Provided is a processing liquid which can be used in a multi-wire saw device, has suitable cutting performance, and exhibits excellent cleaning properties.　Specifically, provided is a processing liquid that contains an active component and water, wherein the active component contains component (A) and component (B), and the content of component (B) is 25.0 mass% or less based on the total amount of the active component. Component (A): one or more types selected from among alkylene glycols and epichlorohydrin-modified polyoxyalkylene compounds. Component (B): an epichlorohydrin-modified polyoxyalkylene compound.

Description

Processing fluid

[0001] The present invention relates to machining fluids.

[0002] In the manufacture of semiconductor products, precise cutting of silicon ingots, a brittle material, is important. For silicon ingot cutting, wire sawing is generally used from the viewpoints of machining accuracy and productivity. Wire sawing is also used for machining materials such as ceramics, quartz, sapphire, and glass. Generally, wire sawing methods include a free abrasive method, in which free abrasive grains are supplied to the sliding contact between the wire and the workpiece, and a fixed abrasive method, in which abrasive grains are fixed to the wire surface. Both of these wire sawing methods use a coolant to improve cutting efficiency, suppress friction between the workpiece and the tool, reduce frictional heat generated during machining, extend tool life, and remove chips. Examples of coolant used for these applications include oil-based coolants primarily composed of mineral oil, animal and vegetable oil, or synthetic oil, and aqueous coolants made water-soluble by blending surfactant compounds. In recent years, water-soluble machining fluids have come to be used from the viewpoints of safety during work and environmental issues.

[0003] For example, Patent Document 1 discloses a water-soluble cutting fluid for silicon ingot slicing, characterized by containing as essential components a polyoxyalkylene adduct having a number average molecular weight of 500 or less and a specific structure, and a monovalent or divalent aliphatic carboxylic acid or a salt thereof having 4 to 10 carbon atoms (including the carbon in the carbonyl group).Patent Document 2 discloses a water-soluble working fluid composition for fixed abrasive wire saws used to cut rare earth magnets, characterized by containing specific amounts of glycols, carboxylic acids, compounds that dissolve in water and exhibit basicity, and water (however, the total of these components is 100 parts by weight). Patent Document 3 discloses a brittle material processing fluid containing at least one selected from the group consisting of alkynediols having an HLB value of 4 or more and 12 or less and alkylene oxide adducts of alkynediols having an HLB value of 4 or more and 12 or less, a nonionic surfactant which is an ethylene oxide adduct having an HLB value of 6 or more and the number of moles of ethylene oxide added in the molecular structure of 5 or more and which does not have a carbon-carbon triple bond, and a carboxylic acid, each in a specific content.

[0004] In both of the above wire sawing methods, a multi-wire saw machine is used to cut multiple wafers from an ingot at once. In a multi-wire saw machine, a wire is wound around each groove on two or more guide rollers, each groove having a plurality of grooves carved at regular intervals. Each wire is held parallel to the other with a constant tension. During cutting, the guide rollers are rotated, and a machining fluid discharged from a nozzle or the like is applied to the wire while the wire travels in one or both directions. The ingot is pressed against the wire to which the machining fluid is applied. The use of a multi-wire saw machine allows for efficient cutting, since a large number of wafers can be cut at once. Furthermore, the narrow cutting margin results in relatively little material loss during cutting, and the machine also has the advantage of being able to easily accommodate larger diameter ingots.

[0005] JP 2011-68884 A JP 2003-82335 A JP 2018-154762 A

[0006] Recently, with the increasing demand for semiconductors, solar cells, and the like, effective utilization of materials has become an issue, particularly from the perspective of reducing the manufacturing costs of semiconductors, solar cells, and the like. In light of this situation, studies have been conducted to further narrow the kerf when slicing wafers using a multi-wire saw machine to reduce material loss during cutting, increase the number of wafers obtained per cutting, and improve material utilization efficiency (yield). One method for further narrowing the kerf to reduce material loss during cutting is to use thinner wires. Another method for increasing the number of wafers obtained per cutting operation is to narrow the wire spacing in the multi-wire saw machine. However, multi-wire saw machines have problems in that the wire saw and the cut wafers, etc., are significantly contaminated by fine chips generated during the cutting process, resulting in a heavy load for cleaning them. It is also necessary to ensure sufficient cutting performance of the wire saw.

[0007] Therefore, an object of the present invention is to provide a machining fluid that can be used in a multi-wire saw device, has appropriate cutting performance, and is excellent in cleanliness.

[0008] According to the present invention, the following items [1] to

[10] are provided. [1] A machining fluid containing an active ingredient and water, wherein the active ingredient contains the following components (A) and (B), and the content of component (B) is 25.0 mass% or less based on the total amount of the active ingredients. Component (A): One or more selected from alkylene glycols and epichlorohydrin-unmodified polyoxyalkylene compounds. Component (B): An epichlorohydrin-modified polyoxyalkylene compound. [2] The machining fluid according to item [1] above, wherein component (A) is a polyoxyalkylene compound. [3] The machining fluid according to item [1] or [2] above, wherein the content of component (A) is 50 to 99.9 mass% based on the total amount of the active ingredients. [4] The machining fluid according to any one of items [1] to [3] above, wherein the content of component (B) is 0.05 to 23.0 mass% based on the total amount of the active ingredients. [5] The working fluid according to any one of [1] to [4] above, wherein the total content of the components (A) and (B) is 50 to 100 mass% based on the total amount of the active ingredients. [6] The working fluid according to any one of [1] to [5] above, which is used when cutting a workpiece made of a brittle material using a multi-wire saw device. [7] The working fluid according to [6] above, wherein the wire constituting the multi-wire saw device is a fixed abrasive wire. [8] The working fluid according to [6] or [7] above, wherein the brittle material is crystalline silicon, sapphire, silicon carbide, gallium nitride, a neodymium magnet, quartz, or glass. [9] The working fluid according to any one of [6] to [8] above, wherein the wire constituting the multi-wire saw device has a strand diameter of 120 μm or less and a wire spacing of 1,100 μm or less.

[10] A method for producing a machining fluid containing an active ingredient and water, comprising a step of mixing the active ingredient with the water, wherein the active ingredient contains the following components (A) and (B), and the content of component (B) is 25.0 mass% or less based on the total amount of the active ingredients: - Component (A): one or more selected from alkylene glycols and epichlorohydrin-unmodified polyoxyalkylene compounds - Component (B): epichlorohydrin-modified polyoxyalkylene compounds

[0009] According to the present invention, it is possible to provide a machining fluid that can be used in a multi-wire saw device, has appropriate cutting performance, and is excellent in cleanliness.

[0010] The upper and lower limits of the numerical ranges described herein can be arbitrarily combined. For example, when "A to B" and "C to D" are described as numerical ranges, the numerical ranges "A to D" and "C to B" are also included in the scope of the present invention. Furthermore, the numerical ranges described herein, "lower limit to upper limit," mean that the range is equal to or greater than the lower limit and equal to or less than the upper limit, unless otherwise specified. Furthermore, in this specification, numerical values ​​in the examples are numerical values ​​that can be used as upper or lower limits. Furthermore, in this specification, unless otherwise specified, a "polyoxyalkylene compound" refers to a compound having an oxyalkylene unit as a repeating unit, the molecular terminal of which may be a hydroxyl group or a hydrocarbyloxy group. Furthermore, the oxyalkylene unit may be one type or a combination of two or more types. The oxyalkylene unit preferably has 2 to 4 carbon atoms. The origin of the oxyalkylene unit is not particularly limited, and it may be derived from an alkylene oxide or a diol. Specific examples of alkylene oxides include ethylene oxide, propylene oxide (PO), oxetane, 1,2-butylene oxide, 2,3-butylene oxide, 1,3-butylene oxide, and tetrahydrofuran.

[0011] [Mode of Machining Fluid] The machining fluid of this embodiment contains an active ingredient and water. The active ingredient contains the following component (A) and component (B), and the content of component (B) based on the total amount of the active ingredients is 25.0 mass% or less. Component (A): One or more selected from alkylene glycols and epichlorohydrin-unmodified polyoxyalkylene compounds. Component (B): Epichlorohydrin-modified polyoxyalkylene compounds.

[0012] The present inventors have conducted extensive research to solve the above problems, and as a result have found that a machining fluid containing the above components can solve the above problems. After further research, the present inventors have completed the present invention.

[0013] The active ingredients contained in the machining fluid of this embodiment will be described in detail below.

[0014] <Component (A)> Component (A) is one or more selected from alkylene glycols and epichlorohydrin-unmodified polyoxyalkylene compounds. The alkylene glycol preferably has 2 to 4 carbon atoms, with propylene glycol being particularly preferred. The epichlorohydrin-unmodified polyoxyalkylene compound is a compound having oxyalkylene units as repeating units, the molecular terminals of which may be hydroxyl groups or hydrocarbyloxy groups. The polyoxyalkylene compound may contain one or more types of oxyalkylene units. When two or more types are combined, the addition of the multiple types of oxyalkylene units may be either random addition or block addition, or a mixture of random addition and block addition, but is preferably a block-added copolymer. Specific examples of the epichlorohydrin-unmodified polyoxyalkylene compound include polyoxyethylene homopolymers, polyoxyethylene polyoxypropylene random copolymers, polyoxyethylene polyoxypropylene block copolymers, and polyoxyalkylene hydrocarbyl ethers having hydrocarbyloxy groups at one or both of the molecular terminals thereof, and polyoxyethylene polyoxypropylene block copolymers or their monohydrocarbyl ethers or dihydrocarbyl ethers are preferably used. The epichlorohydrin-unmodified polyoxyalkylene compound may also be an oligomer of diethylene glycol, dipropylene glycol, or the like.

[0015] Examples of the hydrocarbyloxy group include those having from 1 to 24 carbon atoms. From the viewpoint of the balance between hydrophilicity and lipophilicity, those having from 1 to 14 carbon atoms are preferred, those having from 1 to 10 carbon atoms are more preferred, and those having from 1 to 6 carbon atoms are even more preferred. The hydrocarbyloxy group may be linear, branched, or cyclic, and is preferably linear, although linear or branched alkoxy groups are preferred. The suitable range of the carbon number of the alkoxy group is the same as that of the hydrocarbyloxy group described above.

[0016] The polyoxyalkylene hydrocarbyl ether can be synthesized, for example, by adding an alkylene oxide (hereinafter also referred to as "AO") to an alcohol. The addition of AO to the alcohol can be carried out by a known method, and may be carried out in the absence or presence of a catalyst, under normal pressure or elevated pressure, in one step or in multiple steps.

[0017] Examples of the alcohol include aliphatic alcohols having 1 to 24 carbon atoms. From the viewpoint of the balance between hydrophilicity and lipophilicity, the number of carbon atoms of the alcohol is preferably 1 to 14, more preferably 1 to 10, even more preferably 1 to 6, still more preferably 1 to 4, still more preferably 1 or 2, and still more preferably 1. The aliphatic alcohol is preferably a primary alcohol or a secondary alcohol, more preferably a primary alcohol. Furthermore, the aliphatic alcohol may be linear, branched, or cyclic, with linear being preferred. Examples of the aliphatic alcohol include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, 2-methyl-2-butanol, pentanol, isopentanol, hexanol, 3-methyl-1-pentanol, heptanol, 2-heptanol, 3-heptanol, octanol, 2-ethylhexanol, nonanol, decanol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, isotridecyl alcohol, myristyl alcohol, pentadecyl alcohol, palmityl alcohol, heptadecanol, and stearyl saturated aliphatic alcohols such as ethyl cyclohexyl alcohol, isostearyl alcohol, nonadecyl alcohol, and eicosanol; unsaturated aliphatic alcohols such as octenyl alcohol, decenyl alcohol, dodecenyl alcohol, tridecenyl alcohol, tetradecenyl alcohol, palmitoleyl alcohol, oleyl alcohol, gadoleyl alcohol, and linoleyl alcohol; and cyclic aliphatic alcohols such as ethyl cyclohexyl alcohol, propyl cyclohexyl alcohol, octyl cyclohexyl alcohol, nonyl cyclohexyl alcohol, and adamantyl alcohol.

[0018] Examples of the AO include alkylene oxides having 2 to 4 carbon atoms, such as ethylene oxide (hereinafter also referred to as "EO"), propylene oxide (hereinafter also referred to as "PO"), oxetane, 1,2-butylene oxide, 2,3-butylene oxide, 1,3-butylene oxide, and tetrahydrofuran. Among these, a combination of EO and PO is preferred. Furthermore, when a combination of EO and PO is used as the AO, the addition of the EO and PO at the copolymerization site of the EO and PO may be either random addition or block addition, or a mixture of random addition and block addition may be used.

[0019] Furthermore, the ratio of oxyethylene units is preferably 15 mol% or more, more preferably 20 mol% or more, even more preferably 25 mol% or more, and is preferably 85 mol% or less, more preferably 80 mol% or less, even more preferably 75 mol% or less, based on the total amount of oxyalkylene units contained in the epichlorohydrin-unmodified polyoxyalkylene compound being 100 mol%.

[0020] Furthermore, from the viewpoint of improving lubricity, the mass average molecular weight (Mw) of the epichlorohydrin-unmodified polyoxyalkylene compound is preferably 500 or more, more preferably 1,000 or more, even more preferably 1,500 or more, and even more preferably 2,000 or more. On the other hand, from the viewpoint of improving the bite of the abrasive grains to the workpiece, the mass average molecular weight (Mw) of component (A-1) is preferably 10,000 or less, more preferably 9,000 or less, even more preferably 8,000 or less, and even more preferably 6,000 or less. In this specification, the mass average molecular weight (Mw) value is a value measured using the method described in the Examples below.

[0021] The component (A) may be used alone or in combination of two or more.

[0022] The cloud point of a 1% by mass aqueous solution of the epichlorohydrin-unmodified polyoxyalkylene compound is preferably 15° C. or higher, more preferably 18° C. or higher, and even more preferably 20° C. or higher, from the viewpoint of improving the solubility in water. In this specification, the cloud point of a 1% by mass aqueous solution of the epichlorohydrin-unmodified polyoxyalkylene compound is a value measured using the method described in the Examples below. Note that, as a method for adjusting the cloud point of the epichlorohydrin-unmodified polyoxyalkylene compound, for example, a method of lowering the cloud point by reducing the EO ratio of the epichlorohydrin-unmodified polyoxyalkylene compound can be mentioned.

[0023] The content of component (A) is preferably 50% by mass or more, more preferably 60.0% by mass or more, even more preferably 65.0% by mass or more, even more preferably 70.0% by mass or more, and even more preferably 80.0% by mass or more, based on the total amount of the active ingredients. The content of component (A) is preferably 50 to 99.9% by mass, more preferably 60.0 to 99.8% by mass, and even more preferably 65.0 to 99.5% by mass, based on the total amount of the active ingredients.

[0024] <Component (B)> Component (B) is an epichlorohydrin-modified polyoxyalkylene compound. As component (B), a compound obtained by contacting epichlorohydrin with the epichlorohydrin-unmodified polyoxyalkylene compound described as component (A) above to modify or polymerize it can be used, but it may also be a compound having an oxyalkylene unit derived from the polymerization site of epichlorohydrin obtained by adding epichlorohydrin to alcohol and polymerizing it, or a compound having an oxyalkylene unit as the copolymerization site of alkylene oxide and epichlorohydrin obtained by polymerizing alkylene oxide and epichlorohydrin to alcohol.

[0025] As mentioned above, component (B) is a modified product with epichlorohydrin, and therefore may contain chlorine atoms.

[0026] From the viewpoint of the wafer cutting performance of the processing oil, the content of component (B) must be 25.0 mass% or less, preferably 0.05 to 23.0 mass%, more preferably 0.20 to 20.0 mass%, and particularly preferably 0.50 to 15.0 mass%, based on the total amount of the active ingredients.

[0027] The active ingredient may contain the following component (C): Component (C): Alkylene oxide adduct of alkynediol

[0028] <Component (C)> The component (C) is an alkylene oxide adduct of an alkynediol, and its production method is not particularly limited. Examples of the alkynediol include compounds represented by the following general formula (1):

[0029]

[0030] In general formula (1), R １ ~R ４ R each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. １ ~R ４ is preferably an alkyl group having 1 to 5 carbon atoms. １ ~R ４ Specific examples of alkyl groups having 1 to 6 carbon atoms that can be selected as R include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, and 2,2-dimethylpropyl groups. １ and R ３ is preferably an isobutyl group or a 3-methylbutyl group. ２ and R ４ is preferably a methyl group. In addition, the compound represented by general formula (1) preferably contains R １ and R ３ are identical to each other or R ２ and R ４are compounds having the same structure, and more preferably R １ and R ３ are identical to each other, and R ２ and R ４ are compounds having the same structure as each other.

[0031] Furthermore, as component (C), preferred examples include alkylene oxide adducts of compounds represented by general formula (1) in which AO is added to each hydroxyl group of the compound represented by general formula (1), more preferred examples include alkylene oxide adducts of compounds represented by general formula (1) in which EO and / or PO are added to each hydroxyl group of the compound represented by general formula (1), and even more preferred examples include ethylene oxide adducts of compounds represented by general formula (1) in which EO is added to each hydroxyl group of the compound represented by general formula (1). Note that when the compound contains a structure in which a structure derived from EO (e.g., an ethyleneoxy group or a poly(oxyethylene) structure) and a structure derived from PO (e.g., a propyleneoxy group or a poly(oxypropylene) structure) are bonded, the respective structures may be bonded to each other in a random manner or in a block manner, preferably in a block manner.

[0032] Specific examples of the alkynediol include 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol, 5,8-dimethyl-6-dodecyne-5,8-diol, 2,4,7,9-tetramethyl-5-dodecyne-4,7-diol, 8-hexadecyne-7,10-diol, 7-tetradecyne-6,9-diol, 2,3,6,7-tetramethyl-4-octyne-3,6-diol, 3,6-diethyl-4-octyne-3,6-diol, 2,5-dimethyl-3-hexyne-2,5-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and 3,6-dimethyl-4-octyne-3,6-diol.

[0033] Component (C) is preferably 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol, 5,8-dimethyl-6-dodecyne-5,8-diol, 2,4,7,9-tetramethyl-5-dodecyne-4,7-diol, 8-hexadecyne-7,10-diol, 7-tetradecyne-6,9-diol, 2,3,6,7-tetramethyl-4-octyne-3,6-diol, 3,6-diethyl-4-octyne-3,6-diol, 2, alkylene oxide adducts of one or more alkynediols selected from the group consisting of 5-dimethyl-3-hexyne-2,5-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and 3,6-dimethyl-4-octyne-3,6-diol; more preferably 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol, 5,8-dimethyl-6-dodecyne-5,8-diol, 2,4,7,9-tetramethyl-5 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,3,6,7-tetramethyl-4-octyne-3,6-diol, 3,6-diethyl-4-octyne-3,6-diol, 2,5-dimethyl-3-hexyne-2,5-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and 3,6-dimethyl-4-octyne-3,6-diol. more preferably, one or more selected from the group consisting of an ethylene oxide adduct of 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol and an ethylene oxide adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol; and still more preferably, an ethylene oxide adduct of 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol.

[0034] Component (C) may be used singly or in combination of two or more. Component (C) is preferably one or more selected from the group consisting of alkylene oxide adducts of alkynediols having an HLB value of 4 to 12.

[0035] The content of component (C) is preferably 0.5 to 10.0 mass % based on the total amount of the active ingredients, and more preferably 1.0 to 5.0 mass %.

[0036] <Other Components> The active ingredient may contain components other than component (A), component (B), and component (C) (hereinafter also referred to as "other components") to the extent that the object of the present invention is not impaired. Examples of other components include additives such as surfactants other than the compounds corresponding to component (A), component (B), and component (C), pH adjusters, water retention improvers, antifoaming agents, metal deactivators, bactericides / preservatives, rust inhibitors, and antioxidants. One type of other component may be used alone, or two or more types may be used in combination.

[0037] Surfactants other than the compounds corresponding to components (A), (B), and (C) include anionic surfactants, cationic surfactants, nonionic surfactants other than the compounds corresponding to component (A), and amphoteric surfactants. Examples of anionic surfactants include alkylbenzene sulfonates and alphaolefin sulfonates. Examples of cationic surfactants include quaternary ammonium salts such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, and alkyldimethylbenzylammonium salts. Examples of nonionic surfactants other than the compounds corresponding to components (A), (B), and (C) include amides such as fatty acid alkanolamides. Examples of amphoteric surfactants include betaine-based alkylbetaines.

[0038] pH adjusters are primarily used to adjust the pH of machining fluids. Examples of pH adjusters include various acid components and base components. Adjusting the content ratio of these components allows the appropriate adjustment of the pH of the machining fluid. The acid component and base component may react with each other to form a salt. Therefore, when an acid component and a base component are used as pH adjusters, if a reaction product of the acid component and the base component is present in the machining fluid, the respective contents of the acid component and the base component that contributed to the reaction can be calculated from the contents of the reaction product of the acid component and the base component, as described above. In this case, the machining fluid can be considered to contain the acid component and the base component before the reaction, instead of the reaction product.

[0039] Examples of acid components used as pH adjusters include various fatty acids such as lauric acid, stearic acid, oleic acid, linoleic acid, linolenic acid, neodecanoic acid, isononanoic acid, capric acid, and isostearic acid; carboxylic acids such as acetic acid, malic acid, and citric acid; polymeric acids such as polyacrylic acid and salts thereof; and inorganic acids such as phosphoric acid. Among these, fatty acids are preferred, and fatty acids having 12 or less carbon atoms such as neodecanoic acid, isononanoic acid, capric acid, and dodecanedioic acid are more preferred, with one or more selected from the group consisting of neodecanoic acid, isononanoic acid, capric acid, and dodecanedioic acid being even more preferred.

[0040] Examples of the base component used as a pH adjuster include alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, tri-n-propanolamine, tri-n-butanolamine, triisobutanolamine, tri-tert-butanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-cyclohexylethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-cyclohexyldiethanolamine, N,N-dimethylethanolamine, and N,N-diethylethanolamine; alkylamines such as methylamine, dimethylamine, ethylamine, diethylamine, propylamine, and dipropylamine; and ammonia. Among these, tertiary amines are preferred, and at least one selected from the group consisting of triethanolamine, triisopropanolamine, N-methyldiethanolamine, and N-cyclohexyldiethanolamine is more preferred.

[0041] Examples of water retention enhancers include ethylene glycol, propylene glycol, 1,4-butanediol, hexamethylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, glycerin, ester derivatives thereof, ether derivatives thereof, polyethylene glycol, polypropylene glycol, etc. Antifoaming agents include, for example, silicone oil, fluorosilicone oil, polyether polysiloxane, and fluoroalkyl ether. Metal deactivators include, for example, imidazoline, pyrimidine derivatives, thiadiazole, and benzotriazole. Bactericides and preservatives include, for example, paraoxybenzoic acid esters (parabens), as well as benzoic acid, salicylic acid, sorbic acid, dehydroacetic acid, p-toluenesulfonic acid, and salts thereof, and phenoxyethanol. Rust inhibitors include, for example, alkylbenzenesulfonate, dinonylnaphthalenesulfonate, alkenylsuccinic acid esters, and polyhydric alcohol esters. Examples of antioxidants include phenolic antioxidants and amine antioxidants.

[0042] When the working fluid of the present embodiment contains other components, the total content of the other components may be 0.10% by mass or more, 0.20% by mass or more, or 0.30% by mass or more, based on the total amount of the active ingredients, and may be 30.00% by mass or less, 20.00% by mass or less, 10.00% by mass or less, 5.00% by mass or less, or 3.00% by mass or less.

[0043] <Water> The machining fluid of the present embodiment contains water. The water is not particularly limited, and purified water such as distilled water or ion-exchanged water (deionized water); tap water; industrial water; etc. can be used, with purified water or ion-exchanged water (deionized water) being preferred, and ion-exchanged water (deionized water) being more preferred.

[0044] The water content is adjusted appropriately depending on the usage of the working fluid. For example, when the working fluid of this embodiment is used to process a workpiece (e.g., cutting a brittle material with a multi-wire saw), the water content in the working fluid (hereinafter also referred to as the "water content of the first embodiment") is preferably 95.000% by mass or more, more preferably 97.500% by mass or more, even more preferably 99.500% by mass or more, and particularly preferably 99.600% by mass or more, based on the total amount of the working fluid (100% by mass), from the viewpoint of improving the flame retardancy of the working fluid and enhancing safety, and from the viewpoint of reducing the viscosity of the working fluid and improving handleability. Furthermore, from the viewpoint of ensuring the amount of active ingredients in the working fluid, the water content is preferably 99.910% by mass or less, more preferably 99.900% by mass or less, even more preferably 99.890% by mass or less, even more preferably 99.880% by mass or less, and particularly preferably 99.870% by mass or less. The machining fluid of this embodiment may be concentrated by reducing the amount of water in the machining fluid from the viewpoint of transportation efficiency and storage efficiency. For example, the machining fluid may be a concentrated product obtained by reducing the amount of water in the machining fluid and concentrating it 20 to 2,000 times. Then, when it is used (when machining a workpiece), it may be diluted 20 to 2,000 times with water.

[0045] (Content of Active Component) When the water content of the working fluid of this embodiment is the water content of the first embodiment, the content of the active component is preferably 0.0100 mass% or more, based on 100 mass% of the total amount of the working fluid. A content of the active component of 0.0100 mass% or more can achieve a good compositional balance of the working fluid, making it easier to improve the effects of the present invention. From the perspective of further improving the effects of the present invention, the content of the active component is preferably 0.0150 mass% or more, more preferably 0.0200 mass% or more, and even more preferably 0.0250 mass% or more, based on 100 mass% of the total amount of the working fluid. Furthermore, from the perspective of the solubility of the active component in water, the content of the active component is preferably 2.00 mass% or less, more preferably 0.100 mass% or less, even more preferably 0.0800 mass% or less, and even more preferably 0.0700 mass% or less, based on the total amount of the working fluid.

[0046] (Total Content of Component (A) and Component (B)) In the processing liquid of the present embodiment, the total content of component (A) and component (B) is preferably 50 to 100 mass%, more preferably 60 to 100 mass%, even more preferably 70 to 100 mass%, and particularly preferably 80 to 100 mass%, based on the total amount of the active ingredients.

[0047] [Physical Properties of Machining Fluid] The machining fluid of this embodiment preferably satisfies the following physical properties.

[0048] <Si friction coefficient> The Si friction coefficient of the working fluid of this embodiment is preferably 0.30 or more, more preferably 0.32 or more, and even more preferably 0.35 or more, from the viewpoint of the cutting performance of the working fluid, and is preferably 0.75 or less, more preferably 0.70 or less, and even more preferably 0.65 or less, from the viewpoint of imparting appropriate lubricity to the working fluid. In this specification, the Si friction coefficient of the working fluid is a value measured using the method described in the examples below.

[0049] [Method for Producing Machining Fluid] The method for producing the machining fluid of this embodiment is not particularly limited. For example, the method for producing the machining fluid of this embodiment is a method for producing a machining fluid containing an active ingredient and water, which includes a step of mixing the active ingredient with the water, and the active ingredient contains the following components (A) and (B): Component (A): one or more selected from alkylene glycol epichlorohydrin-unmodified polyoxyalkylene compounds; and Component (B): epichlorohydrin-modified polyoxyalkylene compound.

[0050] The order in which components (A) and (B) are blended is not particularly limited. For example, components (A) and (B) may be blended sequentially or simultaneously with water, or components (A) and (B) may be blended in advance and the resulting mixture may be blended with water. In this production method, components (A) and (B) may be blended with water, and then component (C) and other components may be blended as needed. In such cases, the order and method of blending the components are not particularly limited. Note that components (A), (B), water, and other components are each similar to those described above, and preferred embodiments are also similar, so detailed description thereof is omitted. Furthermore, the preferred amounts and ratios of components (A), (B), water, (C), and other components are similar to the respective contents and content ratios in the working fluid described above, so detailed description thereof is omitted.

[0051] [Uses of the machining fluid] The machining fluid of this embodiment can prevent wire breakage even when the wires are thinned and the wire spacing is narrowed in a multi-wire saw device, and has appropriate lubricity and excellent cleanliness. Therefore, the machining fluid of this embodiment can be suitably used when cutting a workpiece made of a brittle material using a multi-wire saw device. Fixed abrasive wires can be suitably used as the wires that make up the multi-wire saw device. Note that the machining fluid of this embodiment can be used not only for cutting using a multi-wire saw device, but also for cutting using a single-wire saw device. The wires that make up the single-wire saw device may be fixed abrasive wires.

[0052] Examples of brittle materials include crystalline silicon, sapphire, gallium nitride, silicon carbide, neodymium magnet, quartz crystal, and glass. The machining fluid of the present embodiment is particularly suitable for cutting crystalline silicon, sapphire, or silicon carbide.

[0053] [Method for Machining Brittle Materials] The working fluid of this embodiment can prevent wire breakage even when the wires are thinned and the wire spacing is narrowed in a multi-wire saw device, and has appropriate lubricity and excellent cleanliness. Therefore, the working fluid of this embodiment provides a method for cutting a workpiece made of a brittle material using a multi-wire saw device. Fixed abrasive wires can be suitably used as the wires constituting the multi-wire saw device. Note that the working fluid of this embodiment also provides a method for cutting a workpiece made of a brittle material using a single-wire saw device.

[0054] <Multi-wire Saw Device> The multi-wire saw device mentioned in the present embodiment regarding the use of the machining fluid and the method for machining brittle materials will now be described. A multi-wire saw device used in cutting processes, for example, has two or more guide rollers with multiple grooves carved at regular intervals, with one wire wound around each groove, and each wire held parallel with a constant tension. During cutting, the guide rollers are rotated, and machining fluid ejected from a nozzle or the like is applied to the wire while the wire travels in one or both directions. A silicon ingot is pressed against the wire to which the machining fluid is applied to perform cutting. If necessary, machining may also be performed while the machining fluid is applied to the workpiece itself, such as a silicon ingot. The machining fluid used in cutting is stored in a tank or the like and transported from there to the aforementioned machining chamber nozzle via piping or the like. The machining fluid used during cutting is collected in a used machining fluid receiving tank or the like located below the cutting device. In some cases, the machining fluid may be circulated within the device and reused. The wires constituting the multi-wire saw device preferably have a wire diameter of 120 μm or less, and the spacing between the wires is preferably 1,100 μm or less.

[0055] The spacing between the wires used in processing the brittle material is set appropriately depending on the thickness required for the wafers to be cut out, but is preferably 1000 μm or less, for example, and is also preferably 100 μm or more.

[0056] The present invention will be specifically described with reference to the following examples, although the present invention is not limited to the following examples.

[0057] [Methods for Measuring Various Physical Properties] The properties of the raw materials used in each example and each comparative example were measured according to the procedures shown below.

[0058] (1) Cloud Point of 1% by Mass Aqueous Solution The cloud point of a 1% by mass aqueous solution of component (A) was measured by introducing 100 mL of a 1% by mass aqueous solution of the component to be measured into a 200 mL beaker, and while stirring the aqueous solution at a rotation speed of 400 rpm using a magnetic stirrer (stirring bar length: 30 mm), heating the aqueous solution from 15°C to the cloud point at a temperature increase rate of 5°C / min, and measuring the liquid temperature at which the aqueous solution became cloudy in appearance. Note that the "cloud point" of a compound shown in Table 1 below refers to the "cloud point of a 1% by mass aqueous solution" of the compound.

[0059] (2) HLB Value The HLB value of component (C) was calculated by the Griffin method.

[0060] (3) Mass-average molecular weight The mass-average molecular weight (Mw) was measured by gel permeation chromatography (GPC). GPC was performed using two "TSKgel (registered trademark) SuperMultipore HZ-M" columns manufactured by Tosoh Corporation, tetrahydrofuran as an eluent, and a refractive index detector. The mass-average molecular weight (Mw) was determined using polystyrene as a standard sample.

[0061] [Examples 1 to 10, Comparative Examples 1 to 5] The components listed below were mixed to prepare machining fluids having the compositions shown in Table 1, and the evaluations described below were carried out. The numerical units for the blended compositions in Table 1 are "mass %." Details of each component used to prepare the machining fluids having the compositions shown in Table 1 are described below.

[0062] <Component (A)> - "EO-PO block copolymer 1" A polyoxyalkylene alkyl ether in which the polyoxyalkylene portion is a block copolymer of ethylene oxide (EO) and propylene oxide (PO) (terminal methyl group (terminal alkyl group portion), mass average molecular weight (Mw) = 2,286, EO / PO ratio (molar ratio) = 42 / 58, cloud point of 1% by mass aqueous solution = 43°C) - "EO-PO block copolymer 2" A poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) type block copolymer (mass average molecular weight (Mw) = 2,150, EO / PO ratio (molar ratio) = 30 / 70, cloud point of 1% by mass aqueous solution = 38°C)

[0063] <Component (B)> "Epichlorohydrin modified product 1": an epichlorohydrin modified product of an EO adduct of an alcohol having 9 to 11 carbon atoms. "Epichlorohydrin modified product 2": an epichlorohydrin modified product of an EO adduct of 2-ethylhexanol.

[0064] <Component (C)> "Alkynediol EO adduct" EO adduct of 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol (EO adduct of alkynediol, HLB = 8)

[0065] <Water> ・Ion-exchanged water

[0066] [Evaluation] The machining fluids of the Examples and Comparative Examples were diluted at the dilution ratios shown in Table 1, and the resulting diluted solutions were subjected to the following evaluations.

[0067] <Cleanliness> Each diluted solution was evaluated according to the following procedure. (Evaluation of Cylinder Wall Staining) 50 mL of diluted solution and 0.2 g of fine powder ("Graphite Powder", Fujifilm Wako Pure Chemical Industries, Ltd., special grade) were placed in a 100 mL graduated cylinder, the graduated cylinder was capped, and the cylinder was vigorously shaken up and down 10 times. The degree of staining on the upper inner wall of the graduated cylinder was evaluated according to the following criteria, with a rating of A being acceptable. A: The cylinder wall was slightly stained by the fine powder, and the background near the liquid surface was visible through the stain. B: The cylinder wall was moderately stained by the fine powder, and the background near the liquid surface was somewhat visible through the stain. C: The cylinder wall was heavily stained by the fine powder, and the background near the liquid surface was not visible through the stain.

[0068] <Cutting Performance> Using each diluted solution, a reciprocating friction test was performed under the following test conditions to measure the silicon (Si) friction coefficient. Reciprocating friction tester: "F-2100" manufactured by Orientec Co., Ltd. (Measurement conditions) Ball: 3 / 16 inch SUJ2 Test plate temperature: 50°C Test plate: polycrystalline silicon (surface polished to a mirror finish) Test plate temperature: 50°C Sliding speed: 20 mm / sec Sliding distance: 20 mm Number of reciprocating motions: 150 Load: 100 g (Evaluation) Diluted solutions with a friction coefficient value of 0.30 or higher were considered to pass.

[0069] <State of Diluted Liquid> The state of the diluted liquid was visually inspected and evaluated according to the following criteria: A: Homogeneous liquid C: Separation observed

[0070] The composition of each machining fluid and the evaluation results of the diluted solution are shown in Table 1.

[0071] From Table 1, the following can be seen: The machining fluids of Examples 1 to 10 have excellent cleanliness and exhibit appropriate silicon (Si) friction coefficients. In contrast, the machining fluid of Comparative Example 1 has poor cleanliness, the machining fluids of Comparative Examples 2, 3, and 5 have low silicon (Si) friction coefficients and do not exhibit appropriate values, and the machining fluid of Comparative Example 4 does not become uniform when diluted.

Claims

1. A machining fluid containing an active ingredient and water, wherein the active ingredient contains the following components (A) and (B), and the content of component (B) based on the total amount of the active ingredients is 25.0 mass% or less: Component (A): one or more selected from alkylene glycols and epichlorohydrin-unmodified polyoxyalkylene compounds; and Component (B): epichlorohydrin-modified polyoxyalkylene compounds.

2. The machining fluid according to claim 1, wherein component (A) is a polyoxyalkylene compound.

3. The machining fluid according to claim 1 or 2, wherein the content of component (A) is 50 to 99.9 mass% based on the total amount of the active ingredients.

4. A machining fluid according to any one of claims 1 to 3, wherein the content of component (B) is 0.05 to 23.0 mass% based on the total amount of the active ingredients.

5. The machining fluid according to any one of claims 1 to 4, wherein the total content of component (A) and component (B) is 50 to 100 mass% based on the total amount of the active ingredients.

6. The machining fluid according to any one of claims 1 to 5, which is used when cutting a workpiece made of a brittle material using a multi-wire saw device.

7. The machining fluid according to claim 6, wherein the wires constituting the multi-wire saw device are fixed abrasive wires.

8. The working fluid according to claim 6 or 7, wherein the brittle material is crystalline silicon, sapphire, silicon carbide, gallium nitride, neodymium magnet, quartz crystal, or glass.

9. The machining fluid according to any one of claims 6 to 8, wherein the wires constituting the multi-wire saw device have a strand diameter of 120 μm or less and the spacing between the wires is 1,100 μm or less.

10. A method for producing a machining fluid containing an active ingredient and water, comprising a step of mixing the active ingredient with the water, wherein the active ingredient contains the following components (A) and (B), and the content of component (B) based on the total amount of the active ingredient is 25.0 mass% or less: Component (A): one or more selected from alkylene glycols and epichlorohydrin-unmodified polyoxyalkylene compounds Component (B): epichlorohydrin-modified polyoxyalkylene compounds

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