JP2015127363A - Cutting liquid composition for fixed abrasive grain wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting fluid composition for a fixed abrasive grain wire saw, which exhibits, when cutting a silicon ingot, good dispersibility of cutting powder and permeability into a cut part.SOLUTION: Provided is a cutting fluid composition for a fixed abrasive grain wire saw, comprising a cutting fluid base (component A), at least one surfactant (component B) selected from anionic surfactants, cationic surfactants, and nonionic surfactants having a cloud point of 65°C or more, and water (component C), where viscosity of the composition at 25°C is 1 mPa s or more and 25 mPa s or less, and a total content of the component A is 50 mass% or more and 85 mass% or less. The component A contains both of R-O-(CH-CH-O)-H and R-O-(CH-CH(CH)-O)-H, and the cloud point of the component A is a value in a range of 30°C or more and less than 65°C. Here, the Rand Reach represent an alkyl group having 3 to 8 carbon atoms; p and q represent an average number of moles of addition; and p is an integer between 3 and 6, and q is an integer between 1 and 6.

Description

  The present invention relates to a cutting fluid composition for a fixed abrasive wire saw, a method for producing a silicon wafer using the cutting fluid composition for a fixed abrasive wire saw, and a method for regenerating a cutting fluid composition for a used fixed abrasive wire saw.

  In recent years, silicon has been used for photovoltaic power generation and the like. Therefore, a cutting and cutting method using a fixed-abrasive wire saw has attracted attention as a method for cutting and cutting a silicon ingot. The fixed abrasive method is a method using a fixed abrasive wire saw in which hard abrasive particles such as diamond are fixed to a piano wire.

  The fixed abrasive method has an advantage that the ingot can be used effectively because the cutting margin of the ingot can be reduced. In addition, since no abrasive grains are mixed in the cutting fluid composition, this method makes it possible to stably produce a wafer with less change in properties such as viscosity of the cutting fluid composition at the time of cutting, and easy cleaning of the wafer. Become. Therefore, it is more advantageous than the free abrasive grain method in which a silicon ingot is sliced while supplying a grinding liquid containing SiC (silicon carbide) abrasive grains to a wire such as a piano wire from the viewpoint of environmental friendliness and economy.

  On the other hand, as a cutting fluid composition used when cutting and cutting a silicon ingot, a cutting fluid composition containing a polyether compound as an oil component is known. In recent years, attempts have been made to facilitate disposal of used cutting fluid compositions from the viewpoints of environmental friendliness and improved economic efficiency. In addition, from the viewpoint of improving environmental performance, productivity and economy, it has been attempted to reuse the used cutting fluid composition.

  For example, Patent Document 1 discloses that a dispersion such as abrasive grains or ingot cutting powder and a cutting fluid composition are separated by centrifugation and the cutting fluid composition is reused. Patent Document 2 discloses a cutting fluid composition containing a predetermined amount of a specific polyether compound and a specific surfactant so that cutting powder can be separated from the used cutting fluid composition with high separation efficiency by a simple operation. Things are disclosed. Patent Document 3 discloses a cutting fluid composition containing a polyether compound containing both an ethyleneoxy group and a propyleneoxy group in one molecule as a cutting base, and a used cutting fluid by utilizing a cloud point. A cutting fluid composition is disclosed that enables the cutting powder to be separated from the composition.

JP-A-01-316170 WO2013 / 073618 JP 2011-230275 A

  However, the fixed abrasive method has a problem that a cutting flaw occurs in the wire saw and the life of the wire saw is shortened, and a problem that the smoothness of the cutting surface of the silicon wafer is not good.

  The present invention provides a cutting fluid composition that can satisfactorily perform oil-water separation of drainage fluid containing a used cutting fluid composition and a cutting powder, which is generated by cutting and cutting an ingot, and can contribute to the solution of the above-described problems. And a method for producing a silicon wafer using the cutting fluid composition, and a method for regenerating a cutting fluid composition for a used fixed abrasive wire saw.

Cutting fluid composition for fixed abrasive wire saw of the present invention,
A cutting base (component A);
At least one surfactant (component B) selected from an anionic active agent, a cationic active agent, and a nonionic active agent having a cloud point of 65 ° C. or higher;
Water (component C),
The total content of the cutting base (component A) is 50% by mass or more and 85% by mass or less,
The cutting base (component A) includes both a compound A1 represented by the following general formula (1) and a compound A2 represented by the following general formula (2),
The clouding point of the cutting base (component A) is a value within a range of 30 ° C. or more and less than 65 ° C.,
The viscosity at 25 ° C. of the cutting fluid composition for a fixed abrasive wire saw is 1 mPa · s or more and 25 mPa · s or less.
^{_{R 1 -O- (CH 2 -CH 2}} -O) p -H (1)
^{_{R 2 -O- (CH 2 -CH (}} CH 3) -O) q -H (2)
Where R ¹ and R ² each represents an alkyl group having 3 to 8 carbon atoms, p is an average addition mole number of ethyleneoxy group, q is an average addition mole number of propyleneoxy group, and p is 3 to 3 The number of 6 and q is a number of 1-6.

The method for producing a silicon wafer of the present invention comprises:
Cutting and cutting a silicon ingot with a fixed abrasive wire saw using the cutting fluid composition for a fixed abrasive wire saw of the present invention; and
The cutting fluid composition for the fixed abrasive wire saw is heated by heating the drainage liquid containing the used cutting fluid composition for the fixed abrasive wire saw and the cutting powder of the ingot to 65 ° C. or higher. A step 2 for separating an upper layer mainly composed of a cutting base contained in an object and a lower layer mainly composed of water and cutting powder;
After removing at least the lower layer from the drained liquid after heating, adding at least water to the residual liquid to regenerate the cutting fluid composition for used fixed abrasive wire saws, and
The cutting fluid composition for regenerated fixed abrasive wire saw obtained through steps 1 to 3 is used for cutting and cutting another silicon ingot.

The method for regenerating a cutting fluid composition for a used fixed abrasive wire saw of the present invention,
The used cutting fluid composition for a fixed abrasive wire saw produced by cutting and cutting a silicon ingot with a fixed abrasive wire saw using the cutting fluid composition for a fixed abrasive wire saw of the present invention, and the cutting powder of the ingot Is heated to a temperature of 65 ° C. or higher, whereby an upper layer mainly composed of a cutting base contained in the cutting fluid composition for fixed abrasive wire saw, water and cutting powder as main components. A separation step of separating into a lower layer, and
And a regeneration step of regenerating the used cutting fluid composition for a fixed abrasive wire saw by removing at least the lower layer from the drained liquid after heating and then adding at least water to the residual liquid.

  The present invention is capable of satisfactorily separating oil-water from a waste liquid containing a cutting fluid composition for used fixed abrasive wire saw and cutting powder generated by cutting and cutting a silicon ingot, and cutting powder when cutting a silicon ingot. Is not immediately agglomerated in the vicinity of the cutting part, but is discharged out of the system from the cutting part and dispersed in the cutting fluid composition (hereinafter referred to as dispersibility), and the cutting fluid composition penetrates / penetrates into the cutting part. Cutting fluid composition for fixed abrasive wire saw, which has remarkable properties (hereinafter referred to as penetrability), a method for producing a silicon wafer using the cutting fluid composition for fixed abrasive wire saw, and used fixed abrasive A method for regenerating a cutting fluid composition for a wire saw can be provided.

  In the fixed abrasive method, the present inventors discover the cause of the problem that the wire saw is damaged by cutting to shorten the life of the wire saw and the problem that the smoothness of the cutting surface of the silicon wafer is not good as follows. Thus, the present invention has been found.

  In the fixed abrasive method, the cutting and cutting of the silicon ingot is performed by using a cutting fluid composition for a fixed abrasive wire saw (hereinafter sometimes abbreviated as “cutting fluid composition”), a wire saw and a cutting portion of the silicon ingot or It is performed by moving and running at high speed while supplying the entire silicon ingot and pressing the wire saw against the silicon ingot. However, if a sufficient amount of the cutting fluid composition cannot enter the cutting portion during cutting, that is, if the permeability of the cutting fluid composition is poor, the wire saw cannot sufficiently dissipate heat and the life of the wire saw is shortened.

  Further, when the dispersibility of the cutting powder is poor with respect to the cutting fluid composition that has penetrated into the cutting portion, the smoothness of the cutting surface is impaired, and the wire saw cannot sufficiently dissipate heat, so that the life of the wire saw is shortened. In order to improve the dispersibility of the cutting powder, the cutting fluid composition is composed of an alkyl chain that can be adsorbed to the cutting powder, a hydrophobic unit with high hydrophobicity such as a benzene ring, and ethyleneoxy for suppressing aggregation of the cutting powder. It is necessary to have both steric repulsive units such as a group (EO chain) and a propyleneoxy group (PO chain). However, when considering the dispersion of the cutting powder in the cutting fluid composition, if only the PO chain is introduced as the three-dimensional repulsive unit, the PO powder is hydrophobic, and therefore the cutting powder cannot be dispersed well. If only the EO chain is introduced as a three-dimensional repulsive unit, the EO chain is hydrophilic and difficult to adsorb on the cutting powder, and therefore the hydrophobic unit is restricted to have a long chain length of C8 or longer. . That is, in order to improve the dispersibility of the cutting powder, it is important that the degree of hydrophobicity of the cutting base is appropriate. However, for example, in Patent Document 3 described above, a cutting base in which an EO chain and a PO chain are contained in one molecule is proposed, but the viscosity of the cutting fluid composition is high because the weight average molecular weight of the cutting base is large. Becomes higher, and the permeability of the cutting fluid composition to the cutting portion becomes worse. When a polyether compound containing only an EO chain is used as a cutting base as the steric repulsive unit, as described above, the hydrophobic unit needs to be a hydrophobic unit with a long chain length of C8 or longer, so that the cutting base is used. The weight average molecular weight of the polymer increases and the permeability deteriorates. That is, it is difficult to achieve both high dispersibility of the cutting powder and high penetrability of the cutting fluid composition.

  In the present invention, by using two types of low molecular weight cutting bases having different degrees of hydrophobicity, the degree of increase in viscosity accompanying the mixing of cutting powder into the cutting fluid composition during cutting is reduced by conventional cutting. Since it is smaller than that of the liquid composition, the dispersibility of the cutting powder in the cutting liquid composition and the permeability of the cutting liquid composition into the cutting part during cutting are improved. Moreover, oil-liquid separation using a cloud point can be performed well. Therefore, according to the cutting fluid composition for a fixed abrasive wire saw of the present invention and the silicon wafer manufacturing method using the cutting fluid composition for a fixed abrasive wire saw, the life of the wire saw is increased and the cutting surface of the silicon wafer is smoothened. The improvement of sex can be expected. Moreover, according to the cutting fluid composition for fixed abrasive wire saw and the cutting fluid composition for used fixed abrasive wire saw of the present invention, the recyclability of the used cutting fluid composition for fixed abrasive wire saw is improved. In addition, the cutting powder can be easily discarded.

[Cutting fluid composition for fixed abrasive wire saw]
The cutting fluid composition of the present invention is a cutting fluid composition used for cutting a silicon ingot with a fixed abrasive wire saw, and includes the following two specific cutting bases (component A) and a surfactant (component). B) and water (component C).

(Component A: Cutting base)
The cutting fluid composition according to the present invention contains a cutting base (component A) from the viewpoint of improving the penetration of the cutting fluid composition into the cutting portion, but the cutting powder composition into the cutting fluid composition during cutting is not included. From the viewpoint of suppressing the increase in viscosity accompanying mixing, both of the compound A1 represented by the following general formula (1) and the compound A2 represented by the following general formula (2) are included.
^{_{R 1 -O- (CH 2 -CH 2}} -O) p -H (1)
^{_{R 2 -O- (CH 2 -CH (}} CH 3) -O) q -H (2)
Where R ¹ and R ² each represents an alkyl group having 3 to 8 carbon atoms, p is an average addition mole number of ethyleneoxy group, q is an average addition mole number of propyleneoxy group, and p is 3 to 3 The number of 6 and q is a number of 1-6.

(Compound A1)
The carbon number of R ^{1 in} the general formula (1) is 3 or more, preferably 4 or more, from the viewpoint of improving the dispersibility of the cutting powder in the cutting composition liquid, and is a cutting liquid composition during cutting. From the viewpoint of suppressing an increase in viscosity due to the mixing of the cutting powder into the powder, it is 8 or less, and preferably 6 or less.

  P in the general formula (1) is 3 or more from the viewpoint of suppressing corrosion of iron by the cutting fluid composition and the odor of the cutting fluid composition, and the cutting fluid composition during cutting From the viewpoint of suppressing the increase in viscosity associated with the mixing of the cutting powder, it is preferably 6 or less, preferably 5 or less, and more preferably 4 or less.

  The compound A1 represented by the general formula (1) can be obtained, for example, by adding an alkylene oxide compound to a monohydric alcohol using an alkali such as potassium hydroxide as a catalyst.

  The weight average molecular weight of the compound A1 is preferably 120 or more, more preferably 170 or more, from the viewpoint of improving the oil / water separation property of the cutting fluid composition and the lubricity of the cutting fluid composition, and the cutting portion of the cutting fluid composition. 550 or less is preferable from a viewpoint of the permeability improvement to 470, 470 or less is more preferable, and 300 or less is still more preferable.

  As for compound A1 represented by General formula (1), only 1 type may be contained in the component A, but multiple types may be contained.

(Compound A2)
The carbon number of R ^{2 in} the general formula (2) is 3 or more from the viewpoint of improving dispersibility of the silicon chips in the cutting composition liquid, preferably 4 or more, and the cutting fluid composition during cutting. From the viewpoint of suppressing the increase in viscosity associated with the mixing of the cutting powder into the object, it is 8 or less, and preferably 6 or less.

  Q in the general formula (2) is 1 or more from the viewpoint of improving oil-water separation, and 6 from the viewpoint of suppressing an increase in viscosity associated with mixing of cutting powder into the cutting fluid composition during cutting. Or less, preferably 3 or less, and more preferably 2 or less.

  The compound A2 represented by the general formula (2) can be obtained, for example, by adding an alkylene oxide compound to a monohydric alcohol using an alkali such as potassium hydroxide as a catalyst.

  The weight average molecular weight of Compound A2 is preferably 80 or more, more preferably 100 or more, and the cutting part of the cutting fluid composition from the viewpoints of improving the oil / water separation property of the cutting fluid composition and improving the lubricity of the cutting fluid composition. From the viewpoint of improving the permeability to water, 420 or less is preferable, 360 or less is more preferable, and 250 or less is more preferable.

  As for the compound A2 represented by the general formula (2), only one kind may be contained in the component A, but plural kinds may be contained.

  The clouding point of the cutting base (component A) is the clouding point of the mixture of compound A1 and compound A2, and is 30 ° C. or higher from the viewpoint of ensuring storage stability, but is preferably 32 ° C. or higher, and 35 ° C. or higher. Is more preferable, 40 ° C. or higher is still more preferable, 48 ° C. or higher is more preferable, and from the viewpoint of improving oil-water separation, it is less than 65 ° C., but preferably 60 ° C. or lower, more preferably 58 ° C. or lower. Here, the cloud point of component A is the temperature at which the aqueous solution starts to become cloudy when the temperature of the aqueous solution containing the cutting base (component A) is raised, and is measured by the method described in the examples. can do.

  The total content of the cutting base (component A) in the cutting fluid composition is 50% by mass or more from the viewpoint of improving the oil / water separation property of the cutting fluid composition and improving the lubricity of the cutting fluid composition during cutting. Yes, 55% by mass or more is preferable, 60% by mass or more is more preferable, 65% by mass or more is more preferable, from the viewpoint of improving the separation efficiency of the cutting powder and facilitating cleaning of the silicon wafer, is 85% by mass or less, 82 mass% or less is preferable. The “separation efficiency” of the cutting powder means the “removal rate” of the cutting powder contained in the drainage.

  The content of the compound A2 in the cutting fluid composition is preferably 5% by mass or more from the viewpoint of improving the oil / water separation property of the cutting fluid composition and improving the lubricity of the cutting fluid composition during cutting. More preferably 20% by mass or more, still more preferably 20% by mass or more, still more preferably 40% by mass or more, and preferably 60% by mass or less from the viewpoint of improving the penetration of the cutting fluid composition into the cutting part. 55 mass% or less is more preferable.

  In the component A, the mass ratio of the compound A1 to the compound A2 (compound A1 / compound A2) is 0.4 or more from the viewpoint of suppressing the increase in viscosity accompanying the mixing of the cutting powder into the cutting fluid composition during cutting. Preferably, 0.50 or more is more preferable, 0.52 or more is further preferable, 0.55 or more is more preferable, and from the same viewpoint, 6.0 or less is preferable, 5.0 or less is more preferable, 4.0 The following is more preferable, and 1.0 or less is even more preferable.

  The mass ratio of the cutting base (component A) and water (component C) in the cutting fluid composition (polyether compound (component A) / water (component C)) is from the viewpoint of improving the lubricity of the cutting fluid composition. 1 or more is preferable, 1.5 or more is more preferable, 1.8 or more is further preferable, 2 or more is more preferable, and 5 or less is preferable from the viewpoint of improving the cutting performance of the wire saw due to the cooling effect of the cutting fluid composition. 4.5 or less, more preferably 4 or less, still more preferably 3 or less.

(Component B: Surfactant)
The cutting fluid composition of the present invention is selected from an anionic activator, a cationic activator, and a nonionic activator having a cloud point of 65 ° C. or higher from the viewpoint of improving the cutting performance of the wire saw and improving the separation efficiency of the cutting powder. At least one surfactant (component B).

  Examples of the anionic surfactant include sulfonic acid surfactants, sulfuric acid surfactants, carboxylic acid surfactants, phosphoric acid surfactants, and among these, polyoxyalkylene alkyl sulfates Alkyl sulfate, alkyl ether sulfate, alkyl benzene sulfonate and the like are preferable. These anionic active agents may be used alone or in combination of two or more. The counter ion is a cation, and examples thereof include alkali metal ions, ammonium ions, and organic quaternary ammonium ions. From the viewpoint of availability and improvement in cutting powder separation efficiency, sodium ions, potassium ions, and ammonium ions are preferred. preferable.

  As the cationic activator, for example, a quaternary salt type cationic surfactant is preferable from the viewpoint of improving the separation efficiency of cutting powder, and alkyl (the alkyl group has 12 to 22 carbon atoms) trimethylammonium salt, dialkyl (The carbon number of the alkyl group is 12 or more and 22 or less) Examples thereof include dimethylammonium salts such as lauryltrimethylammonium salt, myristyltrimethylammonium salt, palmityltrimethylammonium salt, stearyltrimethylammonium salt, oleyltrimethylammonium salt, tallowtrimethyl Ammonium salt, hydrogenated tallow trimethyl ammonium salt, dilauryl dimethyl ammonium salt, dimyristyl dimethyl ammonium salt, dipalmityl dimethyl ammonium salt, distearyl dimethyl ammonium salt Palmityl stearyl dimethyl ammonium salts, and the like. These cationic activators may be used alone or in combination of two or more. From the viewpoint of improving the cutting powder separation efficiency, palmityl trimethyl ammonium salt and stearyl trimethyl ammonium salt are preferred, and stearyl trimethyl. Ammonium salts are more preferred. The counter ion is a monovalent anion and includes halide ions such as chloride ion, bromide ion and iodide ion. Among them, chloride ion and bromide ion are preferable, and chloride ion is more preferable. .

  Examples of the nonionic activator having a cloud point of 65 ° C. or higher include polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, oxyethylene / oxypropylene block copolymers, Among these, polyoxyethylene fatty acid esters are preferable from the viewpoint of improving the oil / water separation property of the cutting fluid composition. Examples of polyoxyethylene alkylaryl ethers include polyoxyethylene nonylphenyl ether. Examples of polyoxyethylene alkyl ethers include polyoxyethylene oleyl ether and polyoxyethylene lauryl ether. Examples of polyoxyethylene fatty acid esters include polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate, and the like.

但し、前記一般式（３）中、ＥＯはエチレンオキシ基であり、ｎはエチレンオキシ基の平均付加モル数であり、ｎは１〜１５０の数であり、ｍはスチレン基の置換数であり、ｍは１〜３の数である。 Among these nonionic active agents having a cloud point of 65 ° C. or higher, a compound represented by the following general formula (3) having a low ability to emulsify the cutting base is preferable.

However, in the said General formula (3), EO is an ethyleneoxy group, n is the average addition mole number of an ethyleneoxy group, n is the number of 1-150, m is the substitution number of a styrene group. , M is a number from 1 to 3.

  The average added mole number n is 1 or more from the viewpoint of improving the dispersibility of the cutting powder, but is preferably 10 or more, more preferably 30 or more, further preferably 40 or more, still more preferably 50 or more, and 60 or more. More preferably, from the viewpoint of improving the oil / water separation property of the cutting fluid composition, it is 150 or less, preferably 100 or less, more preferably 90 or less, still more preferably 80 or less, and even more preferably 70 or less.

  The substitution number m of the styrene group is a number of 1 to 3 from the viewpoint of improving the dispersibility of the cutting powder, but 2 is preferable, and the clouding point represented by the general formula (3) is a nonionic activity of 65 ° C. or higher. The agent is preferably polyoxyethylene distyrenated phenyl ether.

  Further, the HLB value of the nonionic active agent is preferably 12.0 or more, more preferably 16.0 or more, further preferably 18.0 or more, from the viewpoint of improving the separation efficiency of the cutting powder, and the wire saw cutting performance is improved. And from a viewpoint of the separation efficiency improvement of cutting powder, 20.0 or less are preferable, 19.5 or less are more preferable, and 19.0 or less are still more preferable. In addition, in this specification, the HLB value of a nonionic surfactant means what was computed from the formula of HLB value = 20x (mass% of a hydrophilic group) by the Griffin method.

  The content of the surfactant (component B) in the cutting fluid composition is preferably 0.5% by mass or more, and preferably 0.8% by mass or more from the viewpoint of improving the cutting performance of the wire saw and improving the separation efficiency of the cutting powder. More preferably, from the same viewpoint, 5.0 mass% or less is preferable, 3.0 mass% or less is more preferable, and 2.0 mass% or less is still more preferable.

  The mass ratio (component A / component B) of component A and component B in the cutting fluid composition is preferably 10 or more, more preferably 20 or more, still more preferably 40 or more, from the viewpoint of improving the separation efficiency of the cutting powder. The above is more preferable, and from the same viewpoint, 120 or less is preferable, 100 or less is more preferable, and 80 or less is more preferable.

(Component C: water)
Since the cutting fluid composition contains water (component C), the cutting fluid composition can exhibit a cooling effect when cutting with a wire saw.

  Water (component C) may be contained as the remainder of the cutting fluid composition excluding component A and component B and optional components described later. From the viewpoint of improving the lubricity of the composition, the amount is preferably less than 50% by mass and more preferably 45% by mass or less in the cutting fluid composition. The content of water (component C) in the cutting fluid composition is preferably 10% by mass or more, more preferably 15% by mass or more in the cutting fluid composition from the viewpoint of improving the cutting performance of the wire saw due to the cooling effect of the cutting fluid composition. Is more preferable.

  As the water contained in the cutting fluid composition, for example, ultrapure water, pure water, ion exchange water, or distilled water can be used, but ultrapure water, pure water, or ion exchange water is preferable, Ultrapure water is more preferably used. Pure water and ultrapure water can be obtained, for example, by passing tap water through activated carbon, subjecting it to ion exchange treatment, and further distilling it, irradiating it with a predetermined ultraviolet germicidal lamp or passing it through a filter as necessary. Can do. For example, the electrical conductivity at 25 ° C. is often 1 μS / cm or less for pure water and 0.1 μS / cm or less for ultrapure water.

  The viscosity at 25 ° C. of the cutting fluid composition is 1 mPa · s or more, preferably 5 mPa · s or more from the viewpoint of improving the lubricity of the cutting fluid composition, and the permeability of the cutting fluid composition to the cutting portion is preferred. From the viewpoint of improvement, it is 25 mPa · s or less, preferably 15 mPa · s or less, more preferably 12 mPa · s or less, and even more preferably 10 mPa · s or less.

  The cloud point of the cutting fluid composition may be equal to or lower than the temperature of the separation operation. However, the cutting performance of the wire saw is improved, and the separation efficiency of the cutting powder is improved when performing the separation process using the cloud point of the cutting fluid composition. From the viewpoint of 28 ° C. or higher, preferably 30 ° C. or higher, more preferably 32 ° C. or higher, still more preferably 35 ° C. or higher, from the viewpoint of improving the wire saw cutting performance and cutting powder separation efficiency, 60 ° C. or lower is preferable, 55 ° C. or lower is more preferable, 50 ° C. or lower is further preferable, and 46 ° C. or lower is even more preferable. In addition, the cloud point of the cutting fluid composition is preferably 35 ° C. or higher and more preferably 50 ° C. or lower from the viewpoint of storage stability. The cloud point of a cutting fluid composition can be adjusted with the kind of cutting base (component A) and surfactant (component B), and the content ratio of both.

  The cutting fluid composition may optionally contain one or more compounds selected from hydrocarbon compounds, sparingly water-soluble alkyl esters, and sparingly water-soluble alkyl ketones as necessary. By containing these compounds, the lubricity of the cutting fluid composition is improved.

  Examples of the hydrocarbon compound include paraffins and / or olefins having a straight-chain or branched-chain saturated or unsaturated bond having 6 to 30 carbon atoms that are liquid at the temperature at which the wafer is cleaned, or Aromatic and / or aliphatic hydrocarbon compounds that are liquid at the temperature at which the wafer is cleaned may be mentioned.

  Examples of the alkyl esters include monoesters, diesters, and triesters having 6 to 40 carbon atoms that are liquid at the temperature at which the wafer is cleaned. Among them, esters of higher fatty acids having 6 to 18 carbon atoms with diols or triols having 2 to 8 carbon atoms; higher alcohols having 1 to 18 carbon atoms and dicarboxylic acids or tricarboxylic acids having 2 to 8 carbon atoms Esters with acids are preferred.

  The alkyl ketones are preferably dialkyl ketones having 6 to 40 carbon atoms.

  The hydrocarbon compounds, poorly water-soluble alkyl esters and poorly water-soluble alkyl ketones may be used alone or in admixture of two or more.

  The cutting fluid composition may further contain additives such as a thickener, a dispersant, a rust inhibitor, and a chelating agent as optional components.

  The cutting fluid composition may contain a water-soluble organic compound as a medium for various components such as the component A.

(Method for preparing cutting fluid composition)
The method for preparing the cutting fluid composition is not limited at all, and can be prepared by mixing the cutting base (component A), the surfactant (component B) and water (component C), and further optional components. . After mixing each component, it can be adjusted to a predetermined pH using a pH adjuster. The surfactant (component B) is preferably mixed with water in advance to form an aqueous solution from the viewpoint of improving the operability for preparing the cutting fluid composition.

  The cutting fluid composition can be used as a cutting fluid when cutting a silicon ingot for producing a silicon wafer.

(Silicon wafer manufacturing method and used cutting fluid composition regeneration method)
The method for producing a silicon wafer of the present invention comprises a step 1 of cutting and cutting a silicon ingot with a fixed abrasive wire saw using the cutting fluid composition of the present invention, and a used aqueous cutting fluid produced in the step 1; An upper layer mainly composed of a cutting base contained in the cutting fluid composition by heating a drainage liquid containing the cutting powder of the ingot to a temperature of 65 ° C. or higher (separation operation temperature), water, Step 2 for separating into a lower layer mainly composed of cutting powder, and after removing at least the lower layer from the drained liquid after heating, at least water is added to the remaining liquid to regenerate the used cutting fluid composition The regenerated cutting fluid composition obtained through the steps 1 to 3 including the step 3 is used for cutting and cutting another silicon ingot. The method for regenerating a used cutting fluid composition according to the present invention includes a used cutting fluid composition produced by cutting and cutting a silicon ingot with a fixed abrasive wire saw using the cutting fluid composition of the present invention and the ingot. An upper layer mainly composed of a cutting base contained in the cutting fluid composition, water and cutting powder are heated by heating the drainage liquid containing the cutting powder to a temperature of 65 ° C. or higher (separation operation temperature). And a separation step for separating the water-based cutting fluid, and a regeneration step for regenerating the used aqueous cutting fluid by adding at least water to the residual liquid after removing at least the lower layer from the waste liquid after heating. ,including.

  The silicon ingot can be cut and cut by moving the cutting fluid composition at a high speed while supplying the cutting fluid composition to the wire saw and the entire cutting portion of the silicon ingot or the silicon ingot and pressing the wire saw against the silicon ingot.

  There is no restriction | limiting in particular about the wire saw apparatus used for a cutting | disconnection of a silicon ingot, It can carry out using a conventionally well-known apparatus. There are no particular restrictions on the wire saw. For example, diamond or SiC abrasive grains are fixed to a piano wire mainly composed of iron or an iron alloy by plating with nickel, copper or chromium, or are fixed by a resin adhesive. And the like.

  The wire saw is supplied from, for example, a wire saw supply reel, and is wound and arranged in a groove having a predetermined interval provided on the main roller. The wire saw can be moved and moved by rotating the main roller at a predetermined rotation speed, and is usually moved and moved at a high speed so as to be about 400 to 1000 m / min. The wire saw device may be a single type that performs cutting with a single wire.

  Cutting and cutting of the silicon ingot can be performed by moving the cutting fluid composition at a high speed while supplying the cutting fluid composition to the wire saw and the cutting site of the silicon ingot or the entire silicon ingot and pressing the wire saw against the silicon ingot.

  The drained oil produced by cutting and cutting the silicon ingot contains the used cutting fluid composition and the cutting powder, and is temporarily stored, for example, in a dip tank of a wire saw device. When the pH of the drained oil is outside the range of 6.0 or more and 9.0 or less, the pH of the drained liquid is determined from the viewpoint of easily separating the cutting powder from the drained oil with high separation efficiency. It is preferable to adjust within the range of 6.0 or more and 9.0 or less before separating into an upper layer mainly composed of the cutting base contained in the composition and a lower layer mainly composed of water and cutting powder.

  The pH of the drained oil is preferably 6.0 or more, more preferably 7.0 or more, from the viewpoint of improving the cutting powder separation efficiency and suppressing corrosion of the apparatus. The pH of the cutting fluid composition is preferably 9.0 or less, more preferably 8.0 or less, from the viewpoint of suppressing the generation of hydrogen from the cutting powder.

  The pH of the drained oil can be adjusted using a pH adjuster. As a pH adjuster, when raising pH, sodium hydroxide, potassium hydroxide, etc. are used, for example, and sodium hydroxide is preferable from a viewpoint of availability. In the case of lowering the pH, for example, acetic acid, lactic acid and the like are used, and lactic acid is preferable from the viewpoint of availability.

  When separating the cutting powder in the waste oil from other components in the waste oil, first, the waste oil is heated to a temperature of 65 ° C. or higher (separation operation temperature). Since the temperature of 65 ° C. or higher is higher than the cloud point of the cutting base contained in the cutting fluid composition, if the draining fluid is left at the separation operation temperature or is weakly stirred, the draining fluid will be removed from the cutting base. It separates into the upper layer which has an agent (component A) as a main component, and the lower layer which has water and cutting powder as a main component. In order to separate the waste oil, it may be kept at the separation operation temperature for 1 hour, for example. After the drained oil is separated, the state of separation is maintained even at a temperature below the separation operation temperature.

  Here, the clouding point (° C.) of the cutting base is a temperature at which the aqueous solution starts to become clouded when the temperature of the aqueous solution containing the cutting base is increased. When the temperature of the aqueous solution containing the cutting base rises and the movement of water molecules becomes active, the hydrogen bond between the hydrophilic group portion of the cutting base and the water molecules is broken, and the cutting base loses its solubility in water. Therefore, if the waste oil containing cutting base is heated to a temperature equal to or higher than the clouding point of the cutting base and left to stand, the cutting base having a specific gravity smaller than that of water moves to the upper side of the water. Cutting powder having a large specific gravity moves downward, and the drained oil is separated into two layers.

  Further, “comprising component A as the main component” means that the content of component A in the upper layer is greater than any other component that can be included in the upper layer, and “water and cutting powder are the main components. “To” means that the sum of the content of water and the content of the cutting powder in the lower layer is higher than that of any other component that can be included in the lower layer. In addition to the cutting base (component A), the upper layer contains a surfactant (component B) that did not contribute to the transfer of the cutting powder to the aqueous layer, and is included in the above-described cutting fluid composition of the present invention. Of the optional components, components that are hardly soluble in water may be further included, but water and cutting powder are hardly included, and at least cutting powder is preferably not included. On the other hand, in the lower layer, in addition to water (component C) and the cutting powder, a surfactant (component B) transferred to the water layer together with the cutting powder is included, and among the optional components included in the cutting fluid composition of the present invention A component that is easily soluble in water may be further included, and a small amount of the cutting base (component A) may be included.

  The separation operation temperature is preferably 10 to 50 ° C. higher than the cloud point of the cutting base (component A), more preferably 12 to 50 ° C., more preferably 20 to 50 from the viewpoint of improving the cutting powder separation efficiency. Higher temperatures are more preferable, higher temperatures of 30 to 50 ° C are more preferable, and higher temperatures of 40 to 50 ° C are even more preferable. The specific temperature (separation operation temperature) of the heated waste oil is preferably 65 to 90 ° C and more preferably 65 to 85 ° C from the viewpoint of improving the separation efficiency of the cutting powder. Further, from the viewpoint of reducing the amount of energy to be used, it is preferable to heat the oil drainage liquid to a temperature (separation operation temperature) 10 to 40 ° C. higher than the cloud point of the cutting base (component A). Heating to a temperature 30 ° C higher is more preferable, and heating to a temperature higher by 12 to 20 ° C is still more preferable. From the viewpoint of reducing the amount of energy to be used, the specific temperature (separation operation temperature) of the heated waste oil is preferably 65 to 90 ° C, more preferably 65 to 85 ° C. From the viewpoint of improving the separation efficiency of the cutting powder, the drained oil is preferably stirred before and / or during heating.

  From the drained oil separated into the upper layer and the lower layer, at least the lower layer mainly composed of water and cutting powder is removed, but from the viewpoint of improving the quality of the regenerated cutting fluid composition, not only the lower layer but also the lower layer A part of the upper layer adjacent to may also be removed from the drained oil.

  In the regeneration step of the method for regenerating a used cutting fluid composition for a fixed abrasive wire saw according to the present invention, water and, if necessary, residual liquid obtained by removing at least the cutting powder from the drained oil in the separation step At least one of the cutting base (component A), the surfactant (component B) and the optional component is added to obtain a cutting fluid composition for a fixed abrasive wire saw. This can be used for cutting and cutting silicon ingots.

  The amount of cutting base (component A), surfactant (component B), water (component C) and optional components added to the residual liquid is the same as the amount of cutting base (component A) and surfactant in the residual liquid. It is preferable to measure the content of (Component B), water (Component C), and optional components, and to determine based on the measurement results. Alternatively, a cutting base (component A), a surfactant (which is involved in cutting and cutting a silicon ingot with a fixed abrasive wire saw using a cutting fluid composition, and removing at least the lower layer from the drainage liquid ( The amount of reduction of component B) and water (component C) is estimated in advance, for example, the same amount of cutting base (component A), surfactant (component B) and / or water (component C). ) May be replenished to the drained oil or residual liquid obtained by forming one slice product or a plurality of slice products. For the measurement of the content of the cutting base (component A), the surfactant (component B) and the water (component C), for example, titration, NMR measurement, liquid chromatography or the like can be used.

  The present invention further discloses the following <1> to <21>.

但し、前記一般式（３）中、ＥＯはエチレンオキシ基であり、ｎはエチレンオキシ基の平均付加モル数、ｍはスチレン基の置換数であり、ｍは好ましくは１〜３の数、ｎは好ましくは１〜１５０の数である。
＜１５＞ 前記平均付加モル数ｎは、１以上が好ましく、１０以上がより好ましく、３０以上が更に好ましく、４０以上が更により好ましく、５０以上が更により好ましく、６０以上が更により好ましく、１５０以下が好ましく、１００以下がより好ましく、９０以下が更に好ましく、８０以下が更により好ましく、７０以下がより更に好ましい、前記＜１＞〜＜１４＞のいずれかに記載の固定砥粒ワイヤソー用切削液組成物。
＜１６＞ 前記スチレン基の置換数ｍは、１〜３の数であるが、２が好ましい、前記＜１＞〜＜１５＞のいずれかに記載の固定砥粒ワイヤソー用切削液組成物。
＜１７＞ 前記切削液組成物における界面活性剤（成分Ｂ）の含有量は、０．５質量％以上が好ましく、０．８質量％以上がより好ましく、５．０質量％以下が好ましく、３．０質量％以下がより好ましく、２．０質量％以下が更に好ましい、前記＜１＞〜＜１６＞のいずれかに記載の固定砥粒ワイヤソー用切削液組成物。
＜１８＞前記切削液組成物の２５℃における粘度は、１ｍＰａ・ｓ以上であり、５ｍＰａ・ｓ以上が好ましく、２５ｍＰａ・ｓ以下であり、１５ｍＰａ・ｓ以下が好ましく、１２ｍＰａ・ｓ以下がより好ましく、１０ｍＰａ・ｓ以下が更に好ましい、前記＜１＞〜＜１７＞のいずれかに記載の固定砥粒ワイヤソー用切削液組成物。
＜１９＞前記切削液組成物の曇点は、２８℃以上が好ましく、３０℃以上がより好ましく、３２℃以上が更に好ましく、３５℃以上がより更に好ましく、６０℃以下が好ましく、５５℃以下がより好ましく、５０℃以下が更に好ましく、４６℃以下がより更に好ましい、前記＜１＞〜＜１８＞のいずれかに記載の固定砥粒ワイヤソー用切削液組成物。
＜２０＞前記＜１＞〜＜１９＞のいずれかに記載の固定砥粒ワイヤソー用切削液組成物を用いて固定砥粒ワイヤソーにてシリコンインゴットを切削及び切断する工程１と、
前記工程１で生じた、使用済み固定砥粒ワイヤソー用切削液組成物と前記インゴットの切削粉末とを含む排液を６５℃以上の温度に加熱することにより、前記固定砥粒ワイヤソー用切削液組成物に含まれた切削基剤を主成分とする上層と、水と切削粉末とを主成分とする下層とに分離する工程２と、
加熱後の前記排液から、少なくとも下層を除去した後、残液に少なくとも水を加えて、使用済み固定砥粒ワイヤソー用切削液組成物を再生する工程３と、を含み、
前記工程１から工程３を経て得られた再生固定砥粒ワイヤソー用切削液組成物を、別のシリコンインゴットの切削及び切断に使用する、シリコンウエハの製造方法。
＜２１＞前記＜１＞〜＜１９＞のいずれかの項に記載の固定砥粒ワイヤソー用切削液組成物を用いて固定砥粒ワイヤソーにてシリコンインゴットを切削及び切断することによって生じた使用済み固定砥粒ワイヤソー用切削液組成物と前記インゴットの切削粉末とを含む排液を、６５℃以上の温度に加熱することにより、前記固定砥粒ワイヤソー用切削液組成物に含まれた切削基剤を主成分とする上層と、水と切削粉末とを主成分とする下層とに分離する分離工程と、
加熱後の前記排液から、少なくとも下層を除去した後、残液に少なくとも水を加えて、使用済み固定砥粒ワイヤソー用切削液組成物を再生する再生工程と、を含む、使用済み固定砥粒ワイヤソー用切削液組成物の再生方法。 <1> a cutting base (component A);
At least one surfactant (component B) selected from an anionic active agent, a cationic active agent, and a nonionic active agent having a cloud point of 65 ° C. or higher;
Water (component C),
The total content of the component A is 50% by mass or more and 85% by mass or less,
The component A includes both the compound A1 represented by the following general formula (1) and the compound A2 represented by the following general formula (2),
The clouding point of the cutting base (component A) is a value within a range of 30 ° C. or more and less than 65 ° C.,
A cutting fluid composition for a fixed-abrasive wire saw having a viscosity at 25 ° C of 1 mPa · s to 25 mPa · s.
^{_{R 1 -O- (CH 2 -CH 2}} -O) p -H (1)
^{_{R 2 -O- (CH 2 -CH (}} CH 3) -O) q -H (2)
Where R ¹ and R ² each represents an alkyl group having 3 to 8 carbon atoms, p is an average addition mole number of ethyleneoxy group, q is an average addition mole number of propyleneoxy group, and p is 3 to 3 The number of 6 and q is a number of 1-6.
<2> The cutting fluid composition for a fixed abrasive wire saw according to <1>, wherein R ¹ has 3 or more, preferably 4 or more, preferably 8 or less, and preferably 6 or less.
<3> The cutting fluid composition for a fixed abrasive wire saw according to <1> or <2>, wherein p is 3 or more, 6 or less, preferably 5 or less, and more preferably 4 or less.
<4> The number of carbon atoms of R ² is 3 or more, preferably 4 or more, 8 or less, and preferably 6 or less, for the fixed abrasive wire saw according to any one of <1> to <3>. Cutting fluid composition.
<5> The q is 1 or more, 6 or less, preferably 3 or less, more preferably 2 or less, and the cutting fluid composition for a fixed abrasive wire saw according to any one of <1> to <4>. object.
<6> The clouding point of the cutting base is 30 ° C or higher, preferably 32 ° C or higher, more preferably 35 ° C or higher, still more preferably 40 ° C or higher, still more preferably 48 ° C or higher, 65 ° C. Although it is less than 60 degreeC, 60 degreeC or less is preferable and 58 degreeC or less is more preferable, The cutting fluid composition for fixed abrasive wire saws in any one of said <1>-<5>.
<7> The total content of the cutting base in the cutting fluid composition is 50% by mass or more, preferably 55% by mass or more, more preferably 60% by mass or more, and further preferably 65% by mass or more, 85 The cutting fluid composition for a fixed abrasive wire saw according to any one of <1> to <6>, wherein the cutting fluid composition is at most mass%, preferably at most 82 mass%.
<8> The content of the compound A2 in the cutting fluid composition is preferably 5% by mass or more, more preferably 8% by mass or more, still more preferably 20% by mass or more, and still more preferably 40% by mass or more. The cutting fluid composition for a fixed abrasive wire saw according to any one of <1> to <7>, preferably 60% by mass or less and more preferably 55% by mass or less.
<9> The mass ratio of the compound A1 and the compound A2 (compound A1 / compound A2) in the cutting fluid composition is preferably 0.4 or more, more preferably 0.50 or more, and further more preferably 0.52 or more. Preferably, 0.55 or more is more preferable, 6.0 or less is preferable, 5.0 or less is more preferable, 4.0 or less is more preferable, 1.0 or less is more preferable, <1> to <8 > The cutting fluid composition for a fixed abrasive wire saw according to any one of the above.
<10> The weight average molecular weight of the compound A1 is preferably 120 or more, more preferably 170 or more, preferably 550 or less, more preferably 470 or less, and even more preferably 300 or less, any one of <1> to <9> A cutting fluid composition for a fixed abrasive wire saw according to claim 1.
<11> The weight average molecular weight of the compound A2 is preferably 80 or more, more preferably 100 or more, preferably 420 or less, more preferably 360 or less, and even more preferably 250 or less, any one of <1> to <10> A cutting fluid composition for a fixed abrasive wire saw according to claim 1.
<12> The mass ratio of the cutting base (component A) to water (component C) in the cutting fluid composition (polyether compound (component A) / water (component C)) is preferably 1 or more, and 1.5. The above is more preferable, 1.8 or more is further preferable, 2 or more is more preferable, 5 or less is preferable, 4.5 or less is more preferable, 4 or less is further preferable, and 3 or less is more preferable, <1> The cutting fluid composition for fixed abrasive wire saws according to any one of to <11>.
<13> The mass ratio of the component A and the component B (component A / component B) in the cutting fluid composition is preferably 10 or more, more preferably 20 or more, still more preferably 40 or more, still more preferably 60 or more, 120 or less is preferable, 100 or less is more preferable, and 80 or less is still more preferable, The cutting fluid composition for fixed abrasive wire saws in any one of said <1>-<12>.
<14> The fixed abrasive according to any one of <1> to <13>, wherein the surfactant (component B) includes polyoxyethylene styrenated phenyl ether represented by the following general formula (3): Cutting fluid composition for wire saws.

However, in the said General formula (3), EO is an ethyleneoxy group, n is the average addition mole number of an ethyleneoxy group, m is the substitution number of a styrene group, m is the number of 1-3 preferably, n Is preferably a number from 1 to 150.
<15> The average added mole number n is preferably 1 or more, more preferably 10 or more, still more preferably 30 or more, still more preferably 40 or more, still more preferably 50 or more, still more preferably 60 or more, 150 The following is preferable, 100 or less is more preferable, 90 or less is still more preferable, 80 or less is still more preferable, and 70 or less is still more preferable, The cutting for fixed abrasive wire saws in any one of said <1>-<14> Liquid composition.
<16> The cutting fluid composition for a fixed abrasive wire saw according to any one of <1> to <15>, wherein the substitution number m of the styrene group is a number of 1 to 3, but 2 is preferable.
<17> The content of the surfactant (component B) in the cutting fluid composition is preferably 0.5% by mass or more, more preferably 0.8% by mass or more, and preferably 5.0% by mass or less. The cutting fluid composition for a fixed abrasive wire saw according to any one of <1> to <16>, more preferably 0.0 mass% or less, and still more preferably 2.0 mass% or less.
<18> The viscosity at 25 ° C. of the cutting fluid composition is 1 mPa · s or more, preferably 5 mPa · s or more, 25 mPa · s or less, preferably 15 mPa · s or less, more preferably 12 mPa · s or less. The cutting fluid composition for a fixed abrasive wire saw according to any one of <1> to <17>, further preferably 10 mPa · s or less.
<19> The cloud point of the cutting fluid composition is preferably 28 ° C. or higher, more preferably 30 ° C. or higher, further preferably 32 ° C. or higher, still more preferably 35 ° C. or higher, preferably 60 ° C. or lower, and 55 ° C. or lower. The cutting fluid composition for a fixed abrasive wire saw according to any one of the above <1> to <18>, which is more preferably 50 ° C. or lower and even more preferably 46 ° C. or lower.
<20> Step 1 of cutting and cutting a silicon ingot with a fixed abrasive wire saw using the cutting fluid composition for fixed abrasive wire saw according to any one of <1> to <19>,
The cutting fluid composition for the fixed abrasive wire saw is heated by heating the drainage liquid containing the used cutting fluid composition for the fixed abrasive wire saw and the cutting powder of the ingot to 65 ° C. or higher. A step 2 for separating an upper layer mainly composed of a cutting base contained in an object and a lower layer mainly composed of water and cutting powder;
After removing at least the lower layer from the drained liquid after heating, adding at least water to the residual liquid to regenerate the cutting fluid composition for used fixed abrasive wire saws, and
A method for producing a silicon wafer, wherein the cutting fluid composition for regenerated fixed abrasive wire saw obtained through steps 1 to 3 is used for cutting and cutting another silicon ingot.
<21> Used used by cutting and cutting a silicon ingot with a fixed abrasive wire saw using the cutting fluid composition for a fixed abrasive wire saw according to any one of <1> to <19> A cutting base contained in the cutting fluid composition for a fixed abrasive wire saw by heating a drainage liquid containing the cutting fluid composition for a fixed abrasive wire saw and the cutting powder of the ingot to a temperature of 65 ° C. or higher. A separation step of separating into an upper layer mainly composed of water and a lower layer mainly composed of water and cutting powder;
A regeneration step of regenerating a cutting fluid composition for a used fixed abrasive wire saw by removing at least the lower layer from the drained liquid after heating and then adding at least water to the residual liquid to regenerate the cutting fluid composition for the used fixed abrasive wire saw. A method for regenerating a cutting fluid composition for a wire saw.

[Preparation of cutting fluid composition]
The aqueous cutting fluid compositions of Examples 1 to 16 and Comparative Examples 1 to 3 were obtained by blending and mixing the components so that the compositions (mass%) described in Table 1 and Table 2 were obtained. Specifically, water is added to the surfactant or an aqueous solution thereof, and after adjusting the amount of the surfactant and water, they are mixed with two types of cutting bases to form an aqueous cutting fluid composition. Obtained.

  Details of the cutting bases described in Tables 1 and 2 are as follows.

[Synthesis of Cutting Base 1 (Polyether Compound)]
_{(1) C 4 H 9 -O-} (EO) 3 -H n one-butanol 74.1 g (1 mol) Synthesis autoclave (the in Table 1 referred to as "C4 (EO) 3") and KOH (catalyst) After charging 0.30 g (0.4 wt%) and replacing the air in the autoclave with nitrogen, the temperature in the autoclave was raised to 130 ° C. while stirring n-butanol. 132.2 g (3 mol) of ethylene oxide was introduced into the autoclave at a pressure (gauge pressure) of 3.5 kg / cm ² , and n-butanol and ethylene oxide were reacted until the pressure decreased and became constant. . The temperature in the autoclave was lowered to room temperature to obtain about 205 g of C4 (EO) 3. The weight average molecular weight was 190.

(2) Synthesis of C ₄ H ₉ —O— (EO) ₄ —H (abbreviated as “C4 (EO) 4” in Table 2) The amount of ethylene oxide charged was changed to 176.2 g (4 mol) Except for the above, synthesis was performed in the same manner as the synthesis method of C4 (EO) 3. About 250 g of C4 (EO) 4 was obtained. The weight average molecular weight was 234.

_{(3) C 6 H 13 -O-} (EO) 4 -H ( the in Table 2 referred to as "C6 (EO) 4") instead of synthetic n- butanol, n- hexanol 102.2 g (1 mol) The synthesis was performed in the same manner as the synthesis method of C4 (EO) 4 except that was used. About 278 g of C6 (EO) 4 was obtained. The weight average molecular weight was 262.

_{(4) C 8 H 17 -O-} (EO) 4 -H in place of synthetic n- butanol (polyoxyethylene 2-ethylhexyl ether, abbreviated as "2-EH (EO) 4" is in Table 2), The synthesis was performed in the same manner as the synthesis method of C4 (EO) 4 except that 130.2 g (1 mol) of 2-ethylhexanol was used. About 306 g of 2-EH (EO) 4 was obtained. The weight average molecular weight was 290.

(5) Synthesis of C ₄ H ₉ —O— (EO) ₃ (PO) ₂ —H (abbreviated as “C4 (EO) 3 (PO) 2” in Table 2) 74.1 g of n-butanol in an autoclave ( 1 mol) and 0.30 g (0.4 wt%) of KOH (catalyst) were charged, and the air in the autoclave was replaced with nitrogen, and then the temperature in the autoclave was raised to 130 ° C. while stirring butanol. 132.2 g (3 mol) of ethylene oxide was introduced into the autoclave at a pressure (gauge pressure) of 3.5 kg / cm ² , and n-butanol and ethylene oxide were reacted until the pressure decreased and became constant. . Thereafter, the temperature in the autoclave was lowered to 120 ° C. Next, 116 g (2 mol) of propylene oxide was introduced into the autoclave at a pressure (gauge pressure) of 3.5 kg / cm ² . After the butanol derivative and propylene oxide were reacted until the pressure decreased and became constant, the temperature in the autoclave was lowered to room temperature to obtain about 320 g of C4 (EO) 3 (PO) 2. The weight average molecular weight was 306.

但し、式（４）中、ｐ１、ｐ２、ｐ３はいずれもプロピレンオキシ基（ＰＯ）の平均付加モル数であり、ｐ１+ｐ２+ｐ３＝１０である。
オートクレーブに、グリセリン９２．１ｇとＫＯＨ２．８ｇ（３重量％）を仕込み、１１０℃、１．３ｋＰａにて３０分間、オートクレーブ内の脱水を行った。脱水後、オートクレーブ内の空気を窒素で置換し、オートクレーブ内の温度を１３０℃まで昇温した後、プロピレンオキサイドを５８０．１ｇ仕込んだ。１３０℃にて付加反応・熟成を行った後、オートクレーブ内を８０℃まで冷却し、オートクレーブ内を４．０ｋＰａに３０分間保って、オートクレーブ内の未反応プロピレンオキサイドを除去した。未反応のプロピレンオキサイドを除去した後、酢酸３．０ｇをオートクレーブ内に加え、８０℃で３０分間保持して、グリセリンのＰＯ付加物（ＰＯの平均付加モル数１０）を約６５０ｇ得た。重量平均分子量は６７１であった。 (6) Synthesis of a polyether compound represented by the following formula (4) (abbreviated as “GLY (PO) 10” in Table 2)

However, in formula (4), p1, p2, and p3 are all the average added moles of propyleneoxy groups (PO), and p1 + p2 + p3 = 10.
The autoclave was charged with 92.1 g of glycerin and 2.8 g (3% by weight) of KOH and dehydrated in the autoclave at 110 ° C. and 1.3 kPa for 30 minutes. After dehydration, the air in the autoclave was replaced with nitrogen, the temperature in the autoclave was raised to 130 ° C., and then 580.1 g of propylene oxide was charged. After the addition reaction and aging at 130 ° C., the inside of the autoclave was cooled to 80 ° C., and the inside of the autoclave was kept at 4.0 kPa for 30 minutes to remove unreacted propylene oxide in the autoclave. After removing unreacted propylene oxide, 3.0 g of acetic acid was added to the autoclave and kept at 80 ° C. for 30 minutes to obtain about 650 g of PO adduct of glycerin (average number of moles of PO added: 10). The weight average molecular weight was 671.

(7) Synthesis of C ₈ H ₁₇ —O— (EO) ₂ —H (polyoxyethylene 2-ethylhexyl ether, abbreviated as “2-EH (EO) 2” in Table 2) The amount of ethylene oxide charged was 88. The synthesis was performed in the same manner as the synthesis method of 2-EH (EO) 4 described in the above (4) except that the amount was changed to 0.1 g (2 mol). About 215 g of 2-EH (EO) 2 was obtained. The weight average molecular weight was 202.

[Synthesis of Cutting Base 2 (Polyether Compound)]
(1) Synthesis of C ₄ H ₉ —O— (PO) ₂ —H (abbreviated as “C4 (PO) 2” in Table 1) 74.1 g (1 mol) of n-butanol and KOH (catalyst) in an autoclave After charging 0.30 g (0.4 wt%) and replacing the air in the autoclave with nitrogen, the temperature in the autoclave was raised to 130 ° C. while stirring butanol. 116 g (2 mol) of propylene oxide was introduced into the autoclave at a pressure (gauge pressure) of 3.5 kg / cm ² . After the butanol derivative and propylene oxide were reacted until the pressure decreased and became constant, the temperature in the autoclave was lowered to room temperature to obtain about 190 g of C4 (PO) 2. The weight average molecular weight was 174.

_{(2) C 4 H 9 -O-} (PO) 1 -H ( in in Table 2 referred to as "C4 (PO) 1") except for changing the charge of the synthesis of propylene oxide in 58 g (1 mol) of These were synthesized by the same method as that for C4 (PO) 2. About 130 g of C4 (PO) 1 was obtained. The weight average molecular weight was 116.

  Details of the surfactants described in Tables 1 and 2 are as follows.

[Synthesis of surfactant]
(1) Synthesis of polyoxyethylene (65) distyrenated phenyl ether (abbreviated as “formula (3) n = 65, m = 2” in Tables 1 and 2) Distyrenated phenol (manufactured by Kawaguchi Chemical Industry Co., Ltd.) 608 g (2 mol) and 0.56 g (0.01 mol) of potassium hydroxide were charged into an autoclave equipped with a stirrer, a temperature controller and an ethylene oxide introduction device, and the inside of the autoclave was 30 ° C. at 110 ° C. and 1.3 kPa. The water in the autoclave was removed while maintaining for a minute. Thereafter, nitrogen substitution was carried out, and after raising the temperature to 145 ° C., 5720 g (130 mol) of ethylene oxide was introduced into the autoclave at a pressure (gauge pressure) of 3.5 kg / cm ² . The addition reaction was carried out at 145 ° C. until the pressure became constant, and aging was carried out at 145 ° C. for 1 hour, followed by cooling to 80 ° C. Next, an inorganic alkali adsorbent is introduced into the autoclave and filtered to remove potassium hydroxide, and polyoxyethylene (65) distyrenated phenyl ether (HLB) having an average added mole number of ethylene oxide of 65 mol. (18.0) was obtained (however, the numeral 65 in parentheses represents the average number of moles of ethylene oxide added. The same applies hereinafter).

(2) Synthesis of polyoxyethylene (44) distyrenated phenyl ether (abbreviated as “formula (3) n = 44, m = 2” in Table 1) The amount of ethylene oxide charged was changed to 3872 g (88 mol) Except for the above, the synthesis was performed in the same manner as the synthesis of the polyoxyethylene (65) distyrenated phenyl ether. Polyoxyethylene (44) distyrenated phenyl ether (HLB = 15) having an average addition mole number of ethylene oxide of 44 moles was obtained.

<Cationic activator>
Coatamine 86W (manufactured by Kao, stearyltrimethylammonium chloride)
<Nonionic active agent>
Emanon 3119V (manufactured by Kao, polyethylene glycol monostearate, HLB = 19.4)
<Anionic active agent>
Latemul E-1000A (manufactured by Kao, polyoxyethylene (13) distyrenated phenyl ether monosulfate ammonium salt)

[Method for measuring weight average molecular weight]
The weight average molecular weight of the cutting base is a value calculated based on a peak in a chromatogram obtained by applying a gel permeation chromatography (GPC) method under the following conditions.
Column: G4000PWXL + G2500PWXL (manufactured by Tosoh)
Eluent: (0.2 M phosphate buffer) / (CH ₃ CN) = 9/1 (volume ratio)
Flow rate = 1.0 mL / min
Column temperature = 40 ° C
Detector = RI detector Standard material = Polystyrene

  The cutting fluid compositions of Examples 1 to 16 and Comparative Examples 1 to 3, and the clouding points of the cutting base and surfactant used in the preparation thereof were measured by the following methods, and the results are shown in Tables 1 and 2. Indicated.

[Measurement of cloud point]
(Measurement of cloud point of cutting base and nonionic active agent)
(1) Deionized water is added to the sample so that the sample (cutting base or nonionic activator) is 7% by weight, and 50 mL of the resulting aqueous sample solution is placed in a 100 mL test tube.
(2) The test tube is put in a water bath, and the temperature of the sample aqueous solution is increased from room temperature at a rate of 2 ° C./min while manually stirring the sample aqueous solution using a glass rod-shaped thermometer.
(3) When the turbidity does not disappear even after stirring, the temperature of the sample aqueous solution is read.
(4) Remove the test tube from the water bath and gradually lower the temperature of the aqueous sample solution to room temperature while stirring in an atmosphere of 25 ° C.
(5) Repeat (2) to (4) twice, and let the average value of the temperature of the sample aqueous solution read in (3) be the cloud point.

(Measurement of cloud point of cutting fluid composition)
(1) Put 50 mL of the cutting fluid composition into a test tube with a capacity of 100 mL.
(2) The test tube is placed in a water bath, and the temperature of the cutting fluid composition is increased from room temperature at a rate of 2 ° C./min while manually stirring the cutting fluid composition using a glass rod-shaped thermometer.
(3) The temperature of the cutting fluid composition is read when the turbidity does not disappear even after stirring. (4) Remove the test tube from the water bath and gradually lower the temperature to room temperature while stirring in an atmosphere at 25 ° C.
(5) (2) to (4) are repeated twice, and the average value of the temperatures read in (3) is taken as the cloud point of the cutting fluid composition.

  As described below, the cutting fluid composition was evaluated for the dispersibility of the cutting powder, the permeability of the cutting fluid composition to the cut portion, and the oil / water separation property.

[Dispersibility evaluation of cutting powder during cutting]
As a dispersibility evaluation at the time of cutting, the dispersed particle size was measured when the cutting powder was added to the cutting fluid composition so that the content thereof was 10% by mass. A smaller dispersed particle size means better dispersibility.
(1) Into a 50 mL plastic container, 25 g of the cutting fluid composition and 5 g of Si powder having a particle diameter of 5 μmφ (manufactured by High Purity Chemical Co., Ltd.) were added, and then 50 g of Zr beads (particle diameter of 1 mmφ, manufactured by Nikkato) were further added. Added. Next, an actual solar cell using a fixed abrasive wire saw was prepared by setting a poly container in a paint shaker (Pc-1773 manufactured by AsADA), vibrating for 5 hours, and pulverizing Si powder in the cutting fluid composition. A Si powder close to the Si cutting powder generated during the cutting of the Si wafer was prepared. At this time, it was confirmed that the average particle size of the pulverized Si powder was 1.02 μm using a laser diffraction type particle size measuring device (LA-920, manufactured by Horiba, Ltd.).
(2) The prepared liquid containing the pulverized Si powder was centrifuged, and the pulverized Si powder was recovered. Thereafter, the pulverized Si powder was put in a vacuum drier for a whole day and night and dried under reduced pressure.
(3) 5 g of the pulverized Si powder of (2) was put into a 50 mL glass screw tube, and 45 g of the cutting fluid composition was added and sealed. Thereafter, the screw tube was vigorously shaken up and down by 200 times to disperse the Si powder.
(4) The dispersed particle size (average particle size) of the Si powder was measured with a laser diffraction type particle size measuring device (LA-920, manufactured by Horiba, Ltd.).

[Evaluation of penetration of cutting fluid composition into cutting part]
The viscosity of the cutting fluid composition to which the pulverized Si powder was added was measured as a penetrability evaluation of the cutting fluid composition during cutting of the silicon ingot. The amount of Si powder added was 30 parts by mass with respect to 100 parts by mass of the cutting fluid composition.
(1) Into a 50 mL plastic container, 25 g of the cutting fluid composition and 5 g of Si powder having a particle diameter of 5 μmφ (manufactured by High Purity Chemical Co., Ltd.) were added, and then 50 g of Zr beads (particle diameter of 1 mmφ, manufactured by Nikkato) were further added. Added. Next, the poly container was set on a paint shaker (Pc-1773 manufactured by AsADA) and vibrated for 5 hours to pulverize the Si powder in the cutting fluid composition.
(2) Thereafter, a cutting fluid composition stock solution was added to obtain a sample for viscosity measurement so that the amount of Si powder mixed in the Si powder-added cutting fluid composition was 30% by mass, and these were stirred for 1 hour.
(3) The liquid temperature of the viscosity measurement sample was adjusted to 25 ° C., and the viscosity of the viscosity measurement sample was measured with a B-type rotational viscometer (rotor No. 1 60 rpm).
(4) Similarly, the viscosity of the cutting fluid composition stock solution at 25 ° C. was measured.
(5) The difference Δη between the viscosity of the viscosity measurement sample obtained in (3) and the viscosity of the cutting fluid composition stock solution (unused cutting fluid composition) obtained in (4) was calculated.
It means that the smaller the viscosity of the cutting fluid composition to which the Si powder is added, the higher the permeability of the cutting fluid composition to the cut portion.

[Evaluation of oil / water separation]
As an evaluation of oil / water separation, the recovery rate of the cutting base after oil / water separation was measured.
(1) Into a 50 mL plastic container, 25 g of the cutting fluid composition and 5 g of Si powder having a particle diameter of 5 μmφ (manufactured by High Purity Chemical Co., Ltd.) were added, and then 50 g of Zr beads (particle diameter of 1 mmφ, manufactured by Nikkato) were further added. Added. Next, the polycontainer was set on a paint shaker (Pc-1773 manufactured by AsADA) and vibrated for 5 hours, and the Si powder was pulverized in the cutting fluid composition to obtain a sample solution for evaluation.
(2) Next, 20 mL of the sample liquid for evaluation is sampled in a test tube with a spoid, and the temperature of the liquid sample for evaluation is 65 ° C. which is equal to or higher than the cloud point of the cutting base in a warm bath. The temperature was raised to 1, and the mixture was left for 1 hour while maintaining that temperature. Here, what is separated into two layers is an oil layer in the upper layer and an aqueous layer containing Si powder in the lower layer.
(3) The recovered amount of the upper oil layer was measured. Further, the water ratio (%) in the upper oil layer was measured by the Karl Fischer method. The oil ratio (%) was calculated by subtracting the water ratio from 100.
(4) The cutting base recovery rate was calculated from the following equation.
Recovery rate (%) = {(recovered amount of upper oil layer) × (oil content ratio)} ÷ (amount of cutting base in charged cutting fluid composition)

  As shown in Table 1 and Table 2 below, the cutting fluid composition contains Compound A1 and Compound A2 as a cutting base, and the total content of the cutting base in the cutting fluid composition is 50% by mass or more and 85% by mass. When the viscosity of the unused cutting fluid composition is 1 mPa · s or more and 25 mPa · s or less, the dispersibility of the cutting powder and the permeability of the cutting composition during cutting during cutting are good. And oil-water separation can be performed satisfactorily.

  The present invention has good dispersibility of the cutting powder and good penetration of the cutting composition into the cutting part during cutting, and can perform oil-water separation well, increasing the number of recycles, extending the life of the wire saw, silicon wafer This can contribute to improving the smoothness of the cutting surface.

Claims (7)

A cutting base (component A);
At least one surfactant (component B) selected from an anionic active agent, a cationic active agent, and a nonionic active agent having a cloud point of 65 ° C. or higher;
Water (component C),
The total content of the component A is 50% by mass or more and 85% by mass or less,
The component A includes both the compound A1 represented by the following general formula (1) and the compound A2 represented by the following general formula (2),
The clouding point of the cutting base (component A) is a value within a range of 30 ° C. or more and less than 65 ° C.,
A cutting fluid composition for a fixed-abrasive wire saw having a viscosity at 25 ° C of 1 mPa · s to 25 mPa · s.
^{_{R 1 -O- (CH 2 -CH 2}} -O) p -H (1)
^{_{R 2 -O- (CH 2 -CH (}} CH 3) -O) q -H (2)
Where R ¹ and R ² each represents an alkyl group having 3 to 8 carbon atoms, p is an average addition mole number of ethyleneoxy group, q is an average addition mole number of propyleneoxy group, and p is 3 to 3 The number of 6 and q is a number of 1-6.   The cutting fluid composition for a fixed abrasive wire saw according to claim 1, wherein the content of the compound A2 in the cutting fluid composition is 5% by mass or more and 60% by mass or less.   The cutting fluid for fixed-abrasive wire saws according to claim 1 or 2, wherein a mass ratio of the compound A1 and the compound A2 (compound A1 / compound A2) in the cutting fluid composition is 0.4 or more and 6.0 or less. Composition. The cutting fluid for fixed abrasive wire saws according to any one of claims 1 to 3, wherein the surfactant (component B) comprises polyoxyethylene styrenated phenyl ether represented by the following general formula (3). Composition.

However, in the said General formula (3), EO is an ethyleneoxy group, n is the average addition mole number of ethyleneoxy group, m is the substitution number of a styrene group, m is the number of 1-3, n is 1 A number of ~ 150.   The cutting fluid composition for a fixed abrasive wire saw according to any one of claims 1 to 4, wherein the content of Component B is 0.5 mass% or more and 5.0 mass% or less. Step 1 of cutting and cutting a silicon ingot with a fixed abrasive wire saw using the cutting fluid composition for a fixed abrasive wire saw according to any one of claims 1 to 4,
The cutting fluid composition for the fixed abrasive wire saw is heated by heating the drainage liquid containing the used cutting fluid composition for the fixed abrasive wire saw and the cutting powder of the ingot to 65 ° C. or higher. A step 2 for separating an upper layer mainly composed of a cutting base contained in an object and a lower layer mainly composed of water and cutting powder;
After removing at least the lower layer from the drained liquid after heating, adding at least water to the residual liquid to regenerate the cutting fluid composition for used fixed abrasive wire saws, and
A method for producing a silicon wafer, wherein the cutting fluid composition for a regenerated fixed abrasive wire saw obtained through steps 1 to 3 is used for cutting and cutting another silicon ingot. Cutting for used fixed abrasive wire saw generated by cutting and cutting a silicon ingot with a fixed abrasive wire saw using the cutting fluid composition for fixed abrasive wire saw according to any one of claims 1 to 4. An upper layer mainly composed of a cutting base contained in the cutting liquid composition for a fixed abrasive wire saw by heating a drainage liquid containing the liquid composition and the cutting powder of the ingot to a temperature of 65 ° C. or higher. And a separation step of separating into a lower layer mainly composed of water and cutting powder,
A regeneration step of regenerating a cutting fluid composition for a used fixed abrasive wire saw by removing at least the lower layer from the drained liquid after heating and then adding at least water to the residual liquid to regenerate the cutting fluid composition for the used fixed abrasive wire saw. A method for regenerating a cutting fluid composition for a wire saw.