PROCESSING FLUID

Description

TECHNICAL FIELD

The present invention relates to a processing fluid.

BACKGROUND ART

In the production of a semiconductor product, it is important to cut a silicon ingot, which is a brittle material, with high accuracy. From the viewpoints of processing accuracy and productivity, wire saw processing has been generally utilized in the cutting of the silicon ingot. In addition, the wire saw processing has been utilized in the processing of a material, such as a ceramic, quartz, sapphire, or glass.

In general, a processing method including using a wire saw is, for example, a free abrasive grain system in which processing is performed while a free abrasive grain is supplied to a sliding portion between a wire and a workpiece, or a fixed abrasive grain system in which processing is performed with such a wire that an abrasive grain has been fixed to a wire surface in advance.

In addition, in the wire saw processing of each of both the above-mentioned systems, a processing fluid (coolant) has been used for the purposes of, for example, improving processing efficiency at the time of cutting, suppressing friction between a workpiece and a tool for processing the workpiece, reducing frictional heat generated by the processing, exhibiting a lengthening effect on the lifetime of the tool, and removing chips. The processing fluids used in the above-mentioned applications include: an oil-based processing fluid containing a mineral oil, an animal and vegetable oil, a synthetic oil, or the like as a main component; and a water-based processing fluid having imparted thereto water solubility by the blending of a compound having surface-active performance.

In recent years, a processing fluid having imparted thereto water solubility has started to be used from the viewpoints of safety at the time of an operation and an environmental issue.

In, for example, PTL 1, there is a disclosure of a water-soluble cutting fluid for slicing a silicon ingot, the cutting fluid being characterized by including, as essential components, a polyoxyalkylene adduct, which has a number-average molecular weight of 500 or less and has a specific structure, and a monovalent or divalent aliphatic carboxylic acid having 4 to 10 carbon atoms (including the carbon atom of a carbonyl group) or a salt thereof.

In PTL 2, there is a disclosure of a water-soluble processing fluid composition for a fixed abrasive grain wire saw to be used in the cutting of a rare-earth magnet, the water-soluble processing fluid composition for a fixed abrasive grain wire saw being characterized by including a glycol, a carboxylic acid, a compound that shows basicity when dissolved in water, and water at specific contents (provided that the total of these components is 100 parts by weight).

In PTL 3, there is a disclosure of a brittle material processing fluid including one or more kinds selected from the group consisting of: an alkynediol having an HLB value of 4 or more and 12 or less; and an alkylene oxide adduct of the alkynediol having an HLB value of 4 or more and 12 or less, a nonionic surfactant, which is the following ethylene oxide adduct and is free of a carbon-carbon triple bond, and a carboxylic acid at specific contents: the ethylene oxide adduct has an HLB value of 6 or more, and the number of moles added of ethylene oxide in its molecular structure is 5 or more.

Incidentally, in each of the wire saw processing methods of both the above-mentioned systems, a multiwire saw apparatus has been used for cutting a plurality of wafers out of an ingot in one stroke. In the multiwire saw apparatus, one wire is wound around each groove on two or more guide rollers in each of which a plurality of grooves are carved at certain intervals, and the respective wires are held parallel at a certain tension. In addition, at the time of cutting, the following procedure is followed: the respective guide rollers are rotated; while a processing fluid ejected from a nozzle or the like is caused to adhere to the wires, the wires are caused to run unidirectionally or bidirectionally; and the ingot is pressed against the wires to which the processing fluid has adhered, followed by its cutting.

The use of the multiwire saw apparatus enables efficient cutting because the apparatus can cut out many wafers in one stroke. In addition, the apparatus has the following advantages: material loss at the time of cutting is relatively small because a cutting allowance is narrow; and the apparatus can easily cope with an increase in diameter of an ingot.

CITATION LIST

Patent Literature

• • PTL 1: JP 2011-68884 A
  • PTL 2: JP 2003-82335 A
  • PTL 3: JP 2018-154762 A

SUMMARY OF INVENTION

Technical Problem

Incidentally, in recent years, along with increasing demands for a semiconductor, a solar cell, and the like, effective exploitation of a material has become an issue from, for example, the viewpoint of reducing production costs for the semiconductor, the solar cell, and the like. In view of such circumstances, an investigation has been made on an improvement in utilization efficiency (yield) of the material through the following: when a wafer is cut out with a multiwire saw apparatus, material loss at the time of the cutting is reduced by further narrowing a cutting allowance, and the number of acquisitions of wafers that are obtained by one cutting operation is increased.

A method of reducing the material loss at the time of the cutting by further narrowing the cutting allowance is, for example, a method including thinning a wire. In addition, a method of increasing the number of acquisitions of wafers that are obtained by one cutting operation is, for example, a method including narrowing an interval between the wires in the multiwire saw apparatus.

However, in the multiwire saw apparatus, when the interval between the wires is narrowed while the wires are thinned, the frequency at which the wires break at the time of the cutting of an ingot increases. Accordingly, the alleviation of the increase has been desired.

In addition, the following problem occurs: a wire saw, a wafer cut out of the ingot, and the like are significantly contaminated with fine chips produced during the cutting, and hence a load for washing the saw and the like increases.

In view of the foregoing, an object of the present invention is to provide the following processing fluid: even when an interval between wires in a multiwire saw apparatus is narrowed while the wires are thinned, the processing fluid can suppress the breakage of the wires; and the processing fluid has appropriate lubricity and is excellent in cleaning property.

Solution to Problem

According to the present invention, there are provided the following items [1] and [2].

[1]

A processing fluid, including: effective components; and water,

• • wherein the effective components are formed of the following component (A), the following component (B), and the following component (C):
  • component (A): one or more kinds of compounds selected from the group consisting of: an alkynediol having an HLB value of from 4 to 12; and an alkylene oxide adduct of the alkynediol having an HLB value of from 4 to 12;
  • component (B): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond; and
  • component (C): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond, the compound having a clouding point higher than that of the component (B) when turned into a 1 mass % aqueous solution,
  • wherein a content of the component (A) is 3.0 mass % or more with respect to a total amount of the effective components,
  • wherein a total content of the component (B) and the component (C) is 60 mass % or more with respect to the total amount of the effective components,
  • wherein a content ratio [(A)/(C)] of the component (A) to the component (C) is 0.60 or more in terms of mass ratio, and
  • wherein a content ratio [(B)/(C)] of the component (B) to the component (C) is less than 18 in terms of mass ratio.
    [2]

A method of producing a processing fluid including effective components and water,

• • the method including a step of mixing the effective components and the water,
  • wherein the effective components are formed of the following component (A), the following component (B), and the following component (C):
  • component (A): one or more kinds of compounds selected from the group consisting of: an alkynediol having an HLB value of from 4 to 12; and an alkylene oxide adduct of the alkynediol having an HLB value of from 4 to 12;
  • component (B): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond; and
  • component (C): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond, the compound having a clouding point higher than that of the component (B) when turned into a 1 mass % aqueous solution,
  • wherein a blending amount of the component (A) is 3.0 mass % or more with respect to a total amount of the effective components,
  • wherein a total blending amount of the component (B) and the component (C) is 60 mass % or more with respect to the total amount of the effective components,
  • wherein a blending ratio [(A)/(C)] of the component (A) to the component (C) is 0.60 or more in terms of mass ratio, and
  • wherein a blending ratio [(B)/(C)] of the component (B) to the component (C) is less than 18 in terms of mass ratio.

Advantageous Effects of Invention

According to the present invention, the following processing fluid can be provided: even when an interval between wires in a multiwire saw apparatus is narrowed while the wires are thinned, the processing fluid can suppress the breakage of the wires; and the processing fluid has appropriate lubricity and is excellent in cleaning property.

DESCRIPTION OF EMBODIMENTS

The upper limit values and lower limit values of numerical ranges described herein may be freely combined. For example, when the range of “from A to B” and the range of “from C to D” are described as numerical ranges, the numerical range of “from A to D” and the numerical range of “from C to B” are also included in the scope of the present invention.

In addition, the numerical range of “from a lower limit value to an upper limit value” described herein means the lower limit value or more and the upper limit value or less unless otherwise stated.

In addition, in this description, the numerical values of Examples are numerical values that may each be used as an upper limit value or a lower limit value.

The term “alkylene oxide (hereinafter also simply referred to as “AO”) adduct” as used herein encompasses not only a compound having added thereto a single alkylene oxide but also a compound having added thereto a plurality of alkylene oxides, that is, a polyalkylene oxide unless otherwise stated.

An example of the alkylene oxide is an alkylene oxide having 2 to 4 carbon atoms, and examples thereof include ethylene oxide, propylene oxide (PO), oxetane, 1,2-butylene oxide, 2,3-butylene oxide, 1,3-butylene oxide, and tetrahydrofuran.

In addition, in the following description, the term “ethylene oxide” is also simply referred to as “EO”. In addition, the term “propylene oxide” is also simply referred to as “PO”.

[Aspect of Processing Fluid]

A processing fluid according to an embodiment of the present invention includes: effective components; and water.

The effective components are formed of the following component (A), the following component (B), and the following component (C):

• • component (A): one or more kinds of compounds selected from the group consisting of: an alkynediol having an HLB value of from 4 to 12; and an alkylene oxide adduct of the alkynediol having an HLB value of from 4 to 12;
  • component (B): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond;
  • component (C): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond, the compound having a clouding point higher than that of the component (B) when turned into a 1 mass % aqueous solution; and
  • component (D): water.

The processing fluid of this embodiment further satisfies the following requirements:

• • a content of the component (A) is 3.0 mass % or more with respect to a total amount of the effective components;
  • a total content of the component (B) and the component (C) is 60 mass % or more with respect to the total amount of the effective components;
  • a content ratio [(A)/(C)] of the component (A) to the component (C) is 0.60 or more in terms of mass ratio; and
  • a content ratio [(B)/(C)] of the component (B) to the component (C) is less than 18 in terms of mass ratio.

The inventors of the present invention have made extensive investigations with a view to solving the above-mentioned problems.

First, the inventors of the present invention have clarified a cause for an increase in frequency at which wires break at the time of the cutting of an ingot in a multiwire saw apparatus. As a result, the inventors have made sure that the twisting of the wires due to their contact at the time of the cutting of the ingot in the multiwire saw apparatus is a main cause for the increase in frequency at which the wires break at the time of the cutting of the ingot.

In view of the foregoing, the inventors of the present invention have further made extensive investigations including the impartment of appropriate lubricity and an improvement in cleaning property. As a result, the inventors have found that the following processing fluid can solve the above-mentioned problems: the processing fluid includes the above-mentioned component (A), the above-mentioned component (B), and the above-mentioned component (C) as effective components, and the contents and content ratios of these components are adjusted within specific ranges. The inventors have further made various investigations to complete the present invention.

The effective components to be incorporated into the processing fluid of this embodiment are described in detail below.

<Component (A)>

The processing fluid of this embodiment includes the component (A).

The component (A) is one or more kinds of compounds selected from the group consisting of: an alkynediol having an HLB value of from 4 to 12; and an alkylene oxide adduct of the alkynediol having an HLB value of from 4 to 12.

Herein, the HLB value of the component (A) is 4 or more. The alkynediol and the alkylene oxide adduct thereof described above mean compounds each satisfying the predetermined HLB value among compounds generally referred to as “acetylene glycols” (i.e., acetylene glycols in a broad sense) and alkylene oxide adducts thereof.

When the HLB value of the component (A) is 4 or more, the solubility of the component (A) in water can be made appropriate.

From the viewpoint of further facilitating an improvement in solubility of the component (A) in water, the HLB value of the component (A) is preferably 5 or more, more preferably 6 or more, still more preferably 7 or more.

In addition, the HLB value of the component (A) is 12 or less.

When the HLB value of the component (A) is 12 or less, the effect of the present invention is exhibited.

From the viewpoint of further facilitating an improvement in effect of the present invention, the HLB value of the component (A) is preferably 11 or less, more preferably 10 or less, still more preferably 9 or less.

The upper limit values and lower limit values of those numerical ranges may be freely combined. Specifically, the HLB value of the component (A) is preferably from 5 to 11, more preferably from 6 to 10, still more preferably from 7 to 9.

In this description, the hydrophilic-lipophilic balance (HLB) value of the component (A) is a value calculated by Griffin's method.

The alkynediol is, for example, a compound represented by the following general formula (1).

In the general formula (1), R¹ to R⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

R¹ to R⁴ each preferably represent an alkyl group having 1 to 5 carbon atoms.

Specific examples of the alkyl group having 1 to 5 carbon atoms that may be selected as each of R¹ to R⁴ include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1,1-dimethylpropyl group, a 1,2-dimethylpropyl group, and a 2,2-dimethylpropyl group.

R¹ and R³ each preferably represent an isobutyl group or a 3-methylbutyl group among those groups. In addition, R² and R⁴ each preferably represent a methyl group.

In addition, the compound represented by the general formula (1) is preferably a compound having a structure in which R¹ and R³ are identical to each other, or a structure in which R² and R⁴ are identical to each other, more preferably a compound having a structure in which R¹ and R³ are identical to each other, and R² and R⁴ are identical to each other.

In addition, the alkylene oxide adduct of the alkynediol is preferably, for example, an alkylene oxide adduct of the compound represented by the general formula (1), which is obtained by adding AOs to the respective hydroxy groups of the compound represented by the general formula (1), is more preferably, for example, an alkylene oxide adduct of the compound represented by the general formula (1), which is obtained by adding EO and/or PO thereto, and is still more preferably, for example, an alkylene oxide adduct of the compound represented by the general formula (1), which is obtained by adding EO thereto. A suitable aspect of the alkynediol for forming the alkylene oxide adduct of the alkynediol is the same as a suitable aspect of the compound represented by the general formula (1).

When the compound includes 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 may be bonded to each other in a block manner. The structures are preferably bonded each other in a block manner.

Examples of the component (A) include: alkynediols each represented by the general formula (1), such as 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; and alkylene oxide adducts of the alkynediols each represented by the general formula (1). Examples of the alkylene oxide include EO and/or PO.

Among them, alkylene oxide adducts of one or more kinds of alkynediols selected from the group consisting of: 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 are preferred, ethylene oxide adducts of one or more kinds of alkynediols selected from the group consisting of: 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 are more preferred, one or more kinds 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 are still more preferred, and an ethylene oxide adduct of 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol is still further more preferred.

The components (A) may be used alone or in combination thereof.

That is, the component (A) may be one or more kinds selected from the group consisting of the alkynediols each having an HLB value of from 4 to 12, or may be one or more kinds selected from the group consisting of the alkylene oxide adducts of the alkynediols each having an HLB value of from 4 to 12. One or more kinds selected from the group consisting of the alkynediols each having an HLB value of from 4 to 12, and one or more kinds selected from the group consisting of the alkylene oxide adducts of the alkynediols each having an HLB value of from 4 to 12 may be combined.

From the viewpoint of improving the effect of the present invention, the component (A) is preferably one or more kinds selected from the group consisting of the alkylene oxide adducts of the alkynediols each having an HLB value of from 4 to 12 among those components.

(Secondary Alcohol and Alkylene Oxide Adduct of Secondary Alcohol)

The processing fluid of this embodiment may further include, as the component (A), one or more kinds of compounds selected from the group consisting of: a secondary alcohol; and an alkylene oxide adduct of the secondary alcohol.

That is, the processing fluid of this embodiment may further include, as the component (A), the one or more kinds of compounds selected from the group consisting of: the secondary alcohol; and the alkylene oxide adduct of the secondary alcohol in addition to the one or more kinds of compounds selected from the group consisting of: the alkynediol having an HLB value of from 4 to 12; and the alkylene oxide adduct of the alkynediol having an HLB value of from 4 to 12 described above as the component (A).

The one or more kinds of compounds selected from the group consisting of: the secondary alcohol; and the alkylene oxide adduct of the secondary alcohol can complement a function as the component (A) when used in combination with the one or more kinds of compounds selected from the group consisting of: the alkynediol having an HLB value of from 4 to 12; and the alkylene oxide adduct of the alkynediol having an HLB value of from 4 to 12 described above as the component (A).

Herein, preferred examples of the secondary alcohol include secondary alcohols each having 8 to 18 carbon atoms. In addition, the secondary alcohol is preferably a monohydric alcohol. That is, the secondary alcohol is preferably a monohydric secondary alcohol having 8 to 18 carbon atoms. The same holds true for the secondary alcohol for forming the alkylene oxide adduct of the secondary alcohol.

The alkylene oxide adduct of the secondary alcohol is, for example, an alkylene oxide adduct obtained by adding an AO to a hydroxy group of the secondary alcohol, is more preferably, for example, an alkylene oxide adduct obtained by adding EO and/or PO thereto, and is still more preferably, for example, an alkylene oxide adduct obtained by adding EO thereto.

Herein, the one or more kinds of compounds selected from the group consisting of: the secondary alcohol; and the alkylene oxide adduct of the secondary alcohol are each preferably a compound represented by the following general formula (2).

In the general formula (2), R⁵ and R⁶ each independently represent an alkyl group having 1 to 16 carbon atoms, provided that the total number of the carbon atoms of the alkyl groups that may be selected as R⁵ and R⁶ is from 7 to 17.

Although the alkyl group may be linear or branched, the group is preferably branched.

In addition, in the general formula (2), “m” represents an integer of from 0 to 20, preferably an integer of from 1 to 20.

<Component (B)>

The processing fluid of this embodiment includes the component (B).

The component (B) is a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond.

Herein, the clouding point of a 1 mass % aqueous solution of the component (C) is higher than that of the component (B). Accordingly, the clouding point of a 1 mass % aqueous solution of the component (B) is lower than that of the component (C).

The clouding point of the 1 mass % aqueous solution of the component (B) is not limited as long as its value is lower than the clouding point of the 1 mass % aqueous solution of the component (C). However, from the viewpoint of further facilitating an improvement in effect of the present invention, the clouding point of the 1 mass % aqueous solution of the component (B) is lower than the clouding point of the 1 mass % aqueous solution of the component (C) by preferably 10° C. or more, preferably 15° C. or more, more preferably 18° C. or more. Specifically, for example, the clouding point of the 1 mass % aqueous solution of the component (B) is preferably 60° C. or less.

From the viewpoint of facilitating an improvement in solubility of the component (B) in water, the clouding point of the 1 mass % aqueous solution of the component (B) is preferably 15° C. or more, more preferably 18° C. or more, still more preferably 20° C. or more.

In this description, the value of the clouding point of the 1 mass % aqueous solution of the component (B) is a value measured by using a method described in Examples to be described later.

The compound, which includes the copolymerized moiety of ethylene oxide and the alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond, is, for example, one or more kinds selected from the group consisting of: a copolymer of EO and an AO except EO; and a polyoxyethylene alkylene alkyl ether.

The copolymer of EO and the AO except EO is a copolymer of EO and an AO except EO to be described later. The mode of addition between EO and the AO except EO may be random addition or block addition, and the random addition and the block addition may be mixed. However, a copolymer obtained by the block addition therebetween is preferred.

The AO except EO is, for example, an alkylene oxide having 3 or 4 carbon atoms, and examples thereof include propylene oxide (PO), oxetane, 1,2-butylene oxide, 2,3-butylene oxide, 1,3-butylene oxide, and tetrahydrofuran.

The copolymer of EO and the AO except EO is more preferably a copolymer of EO and PO, still more preferably a block copolymer of EO and PO (also referred to as “block copolymer having a polyethylene glycol unit and a polypropylene glycol unit”), still further more preferably a triblock copolymer of EO and PO (also referred to as “triblock copolymer having a polyethylene glycol unit and a polypropylene glycol unit”). In addition, the triblock copolymer of EO and PO may be a triblock copolymer (EO/PO/EO-type) having terminal blocks each formed of EO and an intermediate block formed of PO, or may be a triblock copolymer (PO/EO/PO-type (reverse-type)) having terminal blocks each formed of PO and an intermediate block formed of EO.

The polyoxyethylene alkylene alkyl ether is, for example, an adduct of an alcohol with EO and an AO except EO, and is preferably an adduct of an alcohol with EO and PO.

The alcohol is, for example, an aliphatic alcohol having 1 or more and 24 or less carbon atoms. From the viewpoint of balance between the hydrophilicity and lipophilicity of the alcohol, the number of the carbon atoms of the alcohol is preferably from 1 to 14, more preferably from 1 to 10, still more preferably from 1 to 6, still further more preferably from 1 to 4, still further more preferably 1 or 2, still further more preferably 1.

The aliphatic alcohol is preferably a primary alcohol or a secondary alcohol, more preferably a primary alcohol. In addition, the aliphatic alcohol may be linear, branched, or cyclic, and is preferably linear.

Examples of the aliphatic alcohol include: saturated aliphatic alcohols, such as 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, stearyl 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 ethylcyclohexyl alcohol, propylcyclohexyl alcohol, octylcyclohexyl alcohol, nonylcyclohexyl alcohol, and adamantyl alcohol.

The AO except EO in the polyoxyethylene alkylene alkyl ether is, for example, an alkylene oxide having 3 or 4 carbon atoms, and examples thereof include propylene oxide (PO), oxetane, 1,2-butylene oxide, 2,3-butylene oxide, 1,3-butylene oxide, and tetrahydrofuran. Among them, PO is preferred.

In addition, in the polyoxyethylene alkylene alkyl ether according to the component (B), the mode of addition between EO and the AO except EO in the copolymerized moiety of EO and the AO except EO may be random addition or block addition, and the random addition and the block addition may be mixed.

The polyoxyethylene alkylene alkyl ether may be synthesized by adding EO and the AO to the alcohol. The addition of EO and the AO to the alcohol may be performed by a known method, and may be performed without any catalyst or in the presence of a catalyst, under normal pressure or under pressure, and in one stage or in a plurality of stages.

In addition, in the copolymerized moiety of EO and the AO except EO, from the viewpoint of further facilitating an improvement in effect of the present invention, the content of a constituent unit derived from EO is preferably 15 mol % or more, more preferably 20 mol % or more, still more preferably 25 mol % or more in 100 mol % of the total amount of constituent units for forming the copolymerized moiety, and is preferably 85 mol % or less, more preferably 80 mol % or less, still more preferably 75 mol % or less.

In addition, from the viewpoint of improving the lubricity, the mass-average molecular weight (Mw) of the component (B) is preferably 500 or more, more preferably 1,000 or more, still more preferably 1,500 or more, still further more preferably 2,000 or more. Meanwhile, from the viewpoint of improving the property by which an abrasive grain bites into a workpiece, the mass-average molecular weight (Mw) of the component (B) is preferably 10,000 or less, more preferably 9,000 or less, still more preferably 8,000 or less, still further more preferably 6,000 or less.

In this description, the value of the mass-average molecular weight (Mw) is a value measured by using a method described in Examples to be described later.

The components (B) may be used alone or in combination thereof.

A method of adjusting the clouding point of the component (B) is, for example, a method including reducing the EO ratio of the component (B) to reduce the clouding point.

<Component (C)>

The processing fluid of this embodiment includes the component (C).

The component (C) is a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond, the compound having a clouding point higher than that of the component (B) when turned into a 1 mass % aqueous solution,

Herein, the clouding point of a 1 mass % aqueous solution of the component (C) is higher than that of the component (B).

The clouding point of the 1 mass % aqueous solution of the component (C) is not limited as long as its value is higher than the clouding point of the 1 mass % aqueous solution of the component (B). However, from the viewpoint of further facilitating an improvement in effect of the present invention, the clouding point of the 1 mass % aqueous solution of the component (C) is higher than the clouding point of the 1 mass % aqueous solution of the component (B) by preferably 10° C. or more, more preferably 15° C. or more, still more preferably 18° C. or more.

From the viewpoint of further facilitating an improvement in effect of the present invention, the clouding point of the 1 mass % aqueous solution of the component (C) is preferably 90° C. or less, more preferably 85° C. or less, still more preferably 80° C. or less.

In this description, the value of the clouding point of the 1 mass % aqueous solution of the component (C) is a value measured by using a method described in Examples to be described later.

The compound, which includes the copolymerized moiety of ethylene oxide and the alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond, is, for example, one or more kinds selected from the group consisting of: a copolymer of EO and an AO except EO; and a polyoxyethylene alkylene alkyl ether. Among them, a copolymer of EO and the AO except EO is preferred.

In the copolymer of EO and the AO except EO, the mode of addition between EO and the AO except EO may be random addition or block addition, and the random addition and the block addition may be mixed, but the block addition copolymer is preferred.

The AO except EO is, for example, an alkylene oxide having 3 or 4 carbon atoms, and examples thereof include propylene oxide (PO), oxetane, 1,2-butylene oxide, 2,3-butylene oxide, 1,3-butylene oxide, and tetrahydrofuran.

The copolymer of EO and the AO except EO is more preferably a copolymer of EO and PO, still more preferably a block copolymer of EO and PO, still further more preferably a triblock copolymer of EO and PO, still further more preferably a pluronic-type copolymer (EO-PO-EO-type triblock copolymer) obtained by adding ethylene oxide to polypropylene glycol.

In addition, in the copolymer of EO and the AO except EO serving as the component (C), from the viewpoint of further facilitating an improvement in effect of the present invention, the content of a constituent unit derived from EO is preferably 25 mol % or more, more preferably 30 mol % or more, still more preferably 35 mol % or more, still further more preferably 40 mol % or more in 100 mol % of the total amount of constituent units for forming the copolymer, and is preferably 75 mol % or less, more preferably 70 mol % or less, still more preferably 65 mol % or less, still further more preferably 60 mol % or less.

The description of the polyoxyethylene alkylene alkyl ether according to the component (B) is the same as that explained for the polyoxyethylene alkylene alkyl ether except that the polyoxyethylene alkylene alkyl ethers have different clouding points, and a suitable aspect thereof is also the same.

A method of adjusting the clouding point of the component (C) is, for example, a method including increasing the EO ratio of the component (C) to increase the clouding point.

In addition, from the viewpoint of improving the lubricity, the mass-average molecular weight (Mw) of the component (C) is preferably 500 or more, more preferably 1,000 or more, still more preferably 1,500 or more, still further more preferably 2,000 or more. Meanwhile, from the viewpoint of improving the property by which an abrasive grain bites into a workpiece, the mass-average molecular weight (Mw) of the component (C) is preferably 10,000 or less, more preferably 9,000 or less, still more preferably 8,000 or less, still further more preferably 6,000 or less.

In this description, the value of the mass-average molecular weight (Mw) is a value measured by using a method described in Examples to be described later.

The components (C) may be used alone or in combination thereof.

<Content of Component (A)>

In the processing fluid of this embodiment, the content of the component (A) needs to be 3.0 mass % or more with respect to the total amount of the effective components.

When the content of the component (A) is 3.0 mass % or more, the composition balance of the processing fluid is secured, and hence the effect of the present invention is exhibited.

Herein, from the viewpoint of further facilitating an improvement in effect of the present invention, the content of the component (A) is preferably 3.000 mass or more, more preferably 5.000 mass % or more, still more preferably 8.000 mass % or more, still further more preferably 10.000 mass % or more, yet still further more preferably 12.000 mass % or more, even more preferably 12.300 mass % or more, still even more preferably 12.500 mass % or more with respect to the total amount of the effective components.

<Total Content of Component (B) and Component (C)>

In the processing fluid of this embodiment, the total content of the component (B) and the component (C) needs to be 60 mass % or more with respect to the total amount of the effective components.

When the total content of the component (B) and the component (C) is 60 mass % or more, the composition balance of the processing fluid is secured, and hence the effect of the present invention is exhibited.

Herein, from the viewpoint of further facilitating an improvement in effect of the present invention, the total content of the component (B) and the component (C) is preferably 60.000 mass % or more, more preferably 65.000 mass % or more, still more preferably 68.000 mass % or more, still further more preferably 70.000 mass % or more, yet still further more preferably 72.000 mass % or more, even more preferably 74.000 mass % or more, still even more preferably 75.000 mass % or more with respect to the total amount of the effective components.

<Content Ratio [(A)/(C)] of Component (A) to Component (C)>

In the processing fluid of this embodiment, the content ratio [(A)/(C)] of the component (A) to the component (C) needs to be 0.60 or more in terms of mass ratio.

When the ratio [(A)/(C)] is 0.60 or more, the composition balance of the processing fluid is secured, and hence the effect of the present invention is exhibited.

Herein, from the viewpoint of further facilitating an improvement in effect of the present invention, the ratio [(A)/(C)] is preferably 0.600 or more, more preferably 0.630 or more, still more preferably 0.660 or more, still further more preferably 0.690 or more, and is preferably 3.200 or less, more preferably 3.0 or less, still more preferably 2.800 or less, still further more preferably 2.700 or less.

<Content Ratio [(B)/(C)] of Component (B) to Component (C)>

In the processing fluid of this embodiment, the content ratio [(B)/(C)] of the component (B) to the component (C) needs to be less than 18 in terms of mass ratio.

When the ratio [(B)/(C)] is less than 18, the composition balance of the processing fluid is secured, and hence the effect of the present invention is exhibited.

Herein, from the viewpoint of further facilitating an improvement in effect of the present invention, the ratio [(B)/(C)] is preferably from 1.500 to 18.000, more preferably from 1.500 to 17.000, still more preferably from 2.000 to 15.000, still further more preferably from 2.500 to 12.000.

< [(A)/{(B)+(C)}]>

In the processing fluid of this embodiment, the ratio [(A)/{(B)+(C)}] of the content of the component (A) to the total content of the component (B) and the component (C) is preferably from 0.040 to 2.0, more preferably from 0.040 to 2.000, still more preferably from 0.080 to 1.000, still further more preferably from 0.100 to 0.500 in terms of mass ratio.

When the ratio [(A)/{(B)+(C)}] falls within the above-mentioned ranges, the composition balance of the processing fluid is made satisfactory, and hence an improvement in effect of the present invention can be facilitated.

<Water>

The processing fluid of this embodiment includes the water.

The water is not particularly limited, and purified water, such as distilled water or ion-exchanged water (deionized water), tap water, industrial water, or the like may be used. Among them, purified water or ion-exchanged water (deionized water) is preferred, and ion-exchanged water (deionized water) is more preferred.

The content of the water is appropriately adjusted in accordance with the usage mode of the processing fluid.

For example, the content of the water in the processing fluid of this embodiment (hereinafter also referred to as “content of the water of the first aspect”) when the processing fluid is used in the processing of a workpiece (e.g., the cutting of a brittle material in a multiwire saw apparatus) is preferably 95.000 mass % or more, more preferably 97.500 mass % or more, still more preferably 99.500 mass % or more, still further more preferably 99.600 mass % or more with respect to 100 mass % of the total amount of the processing fluid from the viewpoint of improving the flame retardancy of the processing fluid to improve safety and the viewpoint of reducing the viscosity of the processing fluid to improve the handleability thereof. In addition, from the viewpoint of securing the amounts of the component (A), the component (B), and the component (C) in the processing fluid, the content is 99.910 mass % or less, preferably 99.900 mass % or less, more preferably 99.890 mass % or less, still more preferably 99.880 mass % or less, still further more preferably 99.870 mass % or less.

From, for example, the viewpoints of transportation efficiency and storage efficiency, the processing fluid of this embodiment may be concentrated by reducing the amount of the water in the processing fluid. For example, the processing fluid may be a concentrated product obtained by reducing the amount of the water in the processing fluid to concentrate the processing fluid to from 20 times to 2,000 times. In addition, the concentrated product may be diluted to from 20 times to 2,000 times with water at the time of its use (at the time of the processing of a workpiece).

(Content of Component (A))

When the content of the water in the processing fluid of this embodiment is the content of the water of the first aspect described above, the content of the component (A) is preferably 0.0100 mass % or more with respect to 100 mass % of the total amount of the processing fluid. When the content of the component (A) is 0.0100 mass % or more, the composition balance of the processing fluid can be made satisfactory, and hence an improvement in effect of the present invention can be facilitated.

Herein, from the viewpoint of further facilitating an improvement in effect of the present invention, the content of the component (A) is preferably 0.0150 mass % or more, more preferably 0.0200 mass % or more, still more preferably 0.0250 mass % or more with respect to 100 mass % of the total amount of the processing fluid.

In addition, from the viewpoint of the solubility of the component (A) in water, the content of the component (A) is preferably 0.100 mass % or less, more preferably 0.0800 mass % or less, still more preferably 0.0700 mass % or less with respect to the total amount of the processing fluid.

(Total Content of Component (B) and Component (C))

When the content of the water in the processing fluid of this embodiment is the content of the water of the first aspect described above, the total content of the component (B) and the component (C) is preferably 0.0750 mass % or more with respect to 100 mass % of the total amount of the processing fluid. When the total content of the component (B) and the component (C) is 0.0750 mass % or more, the composition balance of the processing fluid can be made satisfactory, and hence an improvement in effect of the present invention can be facilitated.

Herein, from the viewpoint of further facilitating an improvement in effect of the present invention, the total content of the component (B) and the component (C) is preferably 0.0850 mass % or more, more preferably 0.0950 mass % or more, still more preferably 0.100 mass % or more with respect to the total amount of the processing fluid.

In addition, the total content is preferably 0.600 mass % or less, more preferably 0.500 mass % or less, still more preferably 0.400 mass % or less.

<Other Component>

The processing fluid may include a component except the effective components and the water (hereinafter also referred to as “other component”) to the extent that the object of the present invention is not impaired.

Examples of the other component include additives, such as a surfactant except compounds corresponding to the components (A) to (C), a pH adjuster, a water retentivity improver, an antifoaming agent, a metal deactivator, a germicide or an antiseptic, a rust inhibitor, and an antioxidant.

The other components may be used alone or in combination thereof.

In addition, among the other components, one or more kinds selected from the group consisting of: a surfactant except the components (A) to (C); a pH adjuster; and a water retentivity improver are preferred, one or more kinds selected from the group consisting of: a water retentivity improver; and a pH adjuster are more preferred, and a pH adjuster is still more preferred.

Examples of the surfactant except the compounds corresponding to the components (A) to (C) include an anionic surfactant, a cationic surfactant, a nonionic surfactant except the compounds corresponding to the components (A) to (C), and an amphoteric surfactant.

Examples of the anionic surfactant include an alkylbenzenesulfonic acid salt and an alpha-olefin sulfonic acid salt. Examples of the cationic surfactant include quaternary ammonium salts, such as an alkyltrimethylammonium salt, a dialkyldimethylammonium salt, and an alkyldimethylbenzylammonium salt.

Examples of the nonionic surfactant except the compounds corresponding to the component (A) to (C) include: a polyoxyethylene alkyl ether; a polyoxyalkylene alkyl ether (provided that a polyoxyalkylene moiety is free of a structure derived from an ethylene oxide group); an ether such as a polyoxyethylene alkyl phenyl ether; a compound, which has a clouding point of less than 20° C. or 80° C. or more when turned into a 1 mass % aqueous solution, includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond; an alkynediol having an HLB value of less than 4 or more than 12; an alkylene oxide adduct of the alkynediol having an HLB value of less than 4 or more than 12; and an amide such as a fatty acid alkanol amide.

An example of the amphoteric surfactant is an alkylbetaine which is a betaine-based surfactant.

The pH adjuster is mainly used for adjusting the pH of the processing fluid. Examples of the pH adjuster include various acid components and base components, and the pH of the processing fluid can be appropriately adjusted by adjusting a content ratio between these components.

The acid component and the base component may react with each other to form a salt.

Accordingly, in the case where the acid component and the base component are used as pH adjusters, and a product of the reaction between the acid component and the base component is present in the processing fluid, as described above, the respective contents of the acid component and the base component that have contributed to the reaction may be calculated from the content of the product of the reaction between the acid component and the base component. In addition, in that case, the processing fluid may be regarded as including the acid component and the base component before the reaction instead of the reaction product.

Examples of the acid component to be used as the pH adjuster 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; polymer acids such as polyacrylic acid and salts thereof, and inorganic acids such as phosphoric acid. Among them, fatty acids are preferred, fatty acids each having 12 or less carbon atoms, such as neodecanoic acid, isononanoic acid, capric acid, and dodecanedioic acid, are more preferred, and one or more kinds selected from the group consisting of: neodecanoic acid; isononanoic acid; capric acid; and dodecanedioic acid are still more preferred.

Examples of the base component to be used as the 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 them, tertiary amines are preferred, and at least one kind selected from the group consisting of: triethanolamine; triisopropanolamine; N-methyldiethanolamine; and N-cyclohexyldiethanolamine is more preferred.

Examples of the water retentivity improver include: ethylene glycol, propylene glycol, 1,4-butanediol, hexamethylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, glycerin, ester derivatives thereof, and ether derivatives thereof; and polyethylene glycol and polypropylene glycol.

Examples of the antifoaming agent include a silicone oil, a fluorosilicone oil, a polyether polysiloxane, and a fluoroalkyl ether.

Examples of the metal deactivator include imidazoline, a pyrimidine derivative, thiadiazole, and benzotriazole.

Examples of the germicide or the antiseptic include benzoic acid, salicylic acid, sorbic acid, dehydroacetic acid, p-toluenesulfonic acid, and salts thereof, and phenoxyethanol in addition to paraoxybenzoic acid esters (parabens).

Examples of the rust inhibitor include an alkylbenzene sulfonate, dinonylnaphthalene sulfonate, an alkenyl succinic acid ester, and a polyhydric alcohol ester.

Examples of the antioxidant include a phenol-based antioxidant and an amine-based antioxidant.

When the processing fluid of this embodiment includes the other component, the total content of the other component may be 0.10 part by mass or more, 0.20 part by mass or more, or 0.30 part by mass or more with respect to 100 parts by mass of the total of the component (A), the component (B), and the component (C), and may be 30.00 parts by mass or less, 20.00 parts by mass or less, 10.00 parts by mass or less, 5.00 mass % or less, or 3.00 parts by mass or less.

[Physical Properties of Processing Fluid]

The processing fluid of this embodiment preferably satisfies the following physical property values.

<pH>

The pH of the processing fluid of this embodiment is preferably 3.0 or more, more preferably 4.0 or more, still more preferably 5.0 or more from the viewpoint that the corrosion of the respective wires, a processing apparatus, and the like to be described later in the section “Applications of Processing Fluid” can be suppressed. Meanwhile, the pH of the processing fluid is preferably 10.0 or less, more preferably 9.5 or less, still more preferably 9.0 or less from, for example, the viewpoint that the production of a large amount of hydrogen from chips can be suppressed at the time of the processing of silicon or the like. In addition, the pH of the processing fluid is preferably from 3.0 to 9.0.

In this description, the pH of the processing fluid is a value measured by using a method described in Examples to be described later.

<Si Friction Coefficient>

From the viewpoint of imparting appropriate lubricity to the processing fluid of this embodiment to satisfactorily perform cutting, the Si friction coefficient of the processing fluid is preferably 0.20 or less, more preferably 0.19 or less, still more preferably 0.18 or less, and is preferably 0.10 or more, more preferably 0.11 or more, still more preferably 0.12 or more.

In this description, the Si friction coefficient of the processing fluid is a value measured by using a method described in Examples to be described later.

[Method of producing Processing Fluid]

A method of producing a processing fluid according to an embodiment of the present invention is not particularly limited. For example, the method of producing a processing fluid of this embodiment is a method of producing a processing fluid including effective components and water,

• • the method including a step of mixing the effective components and the water,
  • wherein the effective components are formed of the following component (A), the following component (B), and the following component (C):
  • component (A): one or more kinds of compounds selected from the group consisting of: an alkynediol having an HLB value of from 4 to 12; and an alkylene oxide adduct of the alkynediol having an HLB value of from 4 to 12;
  • component (B): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond; and
  • component (C): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond, the compound having a clouding point higher than that of the component (B) when turned into a 1 mass % aqueous solution,
  • wherein a blending amount of the component (A) is 3.0 mass % or more with respect to a total amount of the effective components,
  • wherein a total blending amount of the component (B) and the component (C) is 60 mass % or more with respect to the total amount of the effective components,
  • wherein a blending ratio [(A)/(C)] of the component (A) to the component (C) is 0.60 or more in terms of mass ratio, and
  • wherein a blending ratio [(B)/(C)] of the component (B) to the component (C) is less than 18 in terms of mass ratio.

The order in which the component (A) to the component (C) are blended is not particularly limited. For example, the component (A), the component (B), and the component (C) may be sequentially or simultaneously blended into the water, or the following may be performed: the component (A), the component (B), and the component (C) are blended in advance, and the mixture is blended into the water.

In addition, in the production method, the following may be performed: the component (A) to the component (C) are blended into the water, and any other component is further blended thereinto as required. In that case, the order in which the respective components to be blended are blended, a blending method, and the like are not particularly limited.

Detailed descriptions of the component (A), the component (B), the component (C), the water, and the other component are omitted because the components are each the same as that described above, and suitable aspects thereof are also the same. In addition, detailed descriptions of suitable blending amounts of the component (A), the component (B), the component (C), the water, and the other component, and suitable blending amount ratios between the respective components are omitted because the amounts and the ratios are the same as the respective contents and the respective content ratios in the processing fluid described above, respectively.

[Applications of Processing Fluid]

Even when an interval between wires in a multiwire saw apparatus is narrowed while the wires are thinned, the processing fluid of this embodiment can suppress the breakage of the wires, and the processing fluid has appropriate lubricity and is excellent in cleaning property. Accordingly, the processing fluid of this embodiment may be suitably used at the time of the cutting of a workpiece formed of a brittle material with the multiwire saw apparatus. Fixed abrasive grain wires may be suitably used as the wires for forming the multiwire saw apparatus.

The processing fluid of this embodiment may be used not only in the cutting with the multiwire saw apparatus but also in cutting with a single-wire saw apparatus. A wire for forming the single-wire saw apparatus may be a fixed abrasive grain wire.

Examples of the brittle material include crystalline silicon, sapphire, gallium nitride, silicon carbide, a neodymium magnet, quartz crystal, and glass. The processing fluid of this embodiment may be particularly suitably used at the time of the cutting of crystalline silicon, sapphire, or silicon carbide among those materials.

[Method of Processing Brittle Material]

Even when an interval between wires in a multiwire saw apparatus is narrowed while the wires are thinned, the processing fluid of this embodiment can suppress the breakage of the wires, and the processing fluid has appropriate lubricity and is excellent in cleaning property.

Accordingly, according to the processing fluid of this embodiment, there is provided a method of cutting a workpiece formed of a brittle material with the multiwire saw apparatus, the method including using the processing fluid. Fixed abrasive grain wires may be suitably used as the wires for forming the multiwire saw apparatus.

According to the processing fluid of this embodiment, there is also provided a method of cutting a workpiece formed of a brittle material with a single-wire saw apparatus, the method including using the processing fluid.

<Multiwire Saw Apparatus>

The multiwire saw apparatus described in the applications of the processing fluid of this embodiment and the method of processing a brittle material is described. In the multiwire saw apparatus to be used in cutting, for example, one wire is wound around each groove on two or more guide rollers in each of which a plurality of grooves are carved at certain intervals, and the respective wires are held parallel at a certain tension. In addition, at the time of the cutting, the following procedure is followed: the respective guide rollers are rotated; while the processing fluid ejected from a nozzle or the like is caused to adhere to the wires, the wires are caused to run unidirectionally or bidirectionally; and a silicon ingot is pressed against the wires to which the processing fluid has adhered, followed by its cutting. In addition, the processing may be performed while the processing fluid is applied to a workpiece itself such as the silicon ingot as required.

The processing fluid to be used in the processing is stored in a tank or the like, and is conveyed therefrom to the above-mentioned processing chamber nozzle through a pipe or the like. In addition, the processing fluid used at the time of the cutting is recovered in a used processing fluid-receiving tank or the like below a cutting apparatus. In addition, in some cases, the processing fluid is reused by being circulated in the apparatus.

Although the element wire diameter of each of the wires to be used in the processing of the brittle material is appropriately selected in accordance with their applications, for example, the element wire diameter is preferably 120 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less, still further more preferably 60 μm or less, yet still further more preferably 45 μm or less, even more preferably 40 μm or less.

In addition, the element wire diameter is preferably 20 μm or more.

Although the interval between the wires to be used in the processing of the brittle material is appropriately set in accordance with a thickness that a wafer to be cut out of the brittle material is required to have, for example, the interval is preferably 1,100 μm or less, more preferably 1,000 μm or less.

In addition, the interval is preferably 100 μm or more.

[One Aspect of the Present Invention to be Provided]

According to one aspect of the present invention, there are provided the following items [1] to [12].

[1]

A processing fluid, including: effective components; and water,

• • wherein the effective components are formed of the following component (A), the following component (B), and the following component (C):
  • component (A): one or more kinds of compounds selected from the group consisting of: an alkynediol having an HLB value of from 4 to 12; and an alkylene oxide adduct of the alkynediol having an HLB value of from 4 to 12;
  • component (B): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond; and
  • component (C): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond, the compound having a clouding point higher than that of the component (B) when turned into a 1 mass % aqueous solution,
  • wherein a content of the component (A) is 3.0 mass % or more with respect to a total amount of the effective components,
  • wherein a total content of the component (B) and the component (C) is 60 mass % or more with respect to the total amount of the effective components,
  • wherein a content ratio [(A)/(C)] of the component (A) to the component (C) is 0.60 or more in terms of mass ratio, and
  • wherein a content ratio [(B)/(C)] of the component (B) to the component (C) is less than 18 in terms of mass ratio.
    [2]

The processing fluid according to the above-mentioned item [1], wherein the alkynediol is a compound represented by the following general formula (1):

• • wherein
  • in the general formula (1), R¹ to R⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
    [3]

The processing fluid according to the above-mentioned item [1] or [2], wherein a 1 mass % aqueous solution of the component (B) has a clouding point of 15° C. or more.

[4]

The processing fluid according to any one of the above-mentioned items [1] to [3], wherein a 1 mass % aqueous solution of the component (C) has a clouding point of 90° C. or less.

[5]

The processing fluid according to any one of the above-mentioned items [1] to [4], further including, as the component (A), one or more kinds of compounds selected from the group consisting of: a secondary alcohol; and an alkylene oxide adduct of the secondary alcohol.

[6]

The processing fluid according to any one of the above-mentioned items [1] to [5], wherein a ratio [(A)/{(B)+(C)}] of the content of the component (A) to the total content of the component (B) and the component (C) is from 0.040 to 2.0 in terms of mass ratio.

[7]

The processing fluid according to any one of the above-mentioned items [1] to [6], wherein the processing fluid has a pH of from 3.0 to 9.0.

[8]

The processing fluid according to any one of the above-mentioned items [1] to [7], wherein the processing fluid is used at a time of cutting of a workpiece formed of a brittle material with a multiwire saw apparatus.

[9]

The processing fluid according to the above-mentioned item [8], wherein wires for forming the multiwire saw apparatus are fixed abrasive grain wires.

[10]

The processing fluid according to the above-mentioned item [8] or [9], wherein the brittle material is crystalline silicon, sapphire, silicon carbide, gallium nitride, a neodymium magnet, quartz crystal, or glass.

[11]

The processing fluid according to any one of the above-mentioned items [8] to [10], wherein wires for forming the multiwire saw apparatus each have an element wire diameter of 120 μm or less, and an interval between the wires is 1,100 μm or less.

[12]

A method of producing a processing fluid including effective components and water,

• • the method including a step of mixing the effective components and the water,
  • wherein the effective components are formed of the following component (A), the following component (B), and the following component (C):
  • component (A): one or more kinds of compounds selected from the group consisting of: an alkynediol having an HLB value of from 4 to 12; and an alkylene oxide adduct of the alkynediol having an HLB value of from 4 to 12;
  • component (B): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond; and
  • component (C): a compound, which includes a copolymerized moiety of ethylene oxide and an alkylene oxide except ethylene oxide, and is free of a carbon-carbon triple bond, the compound having a clouding point higher than that of the component (B) when turned into a 1 mass % aqueous solution,
  • wherein a blending amount of the component (A) is 3.0 mass % or more with respect to a total amount of the effective components,
  • wherein a total blending amount of the component (B) and the component (C) is 60 mass % or more with respect to the total amount of the effective components,
  • wherein a blending ratio [(A)/(C)] of the component (A) to the component (C) is 0.60 or more in terms of mass ratio, and
  • wherein a blending ratio [(B)/(C)] of the component (B) to the component (C) is less than 18 in terms of mass ratio.

EXAMPLES

The present invention is specifically described by way of Examples below. However, the present invention is not limited to Examples below.

[Methods of measuring Various Physical Property Values]

The respective properties of the respective raw materials used in Examples and Comparative Examples were measured in accordance with the following procedures.

(1) Clouding Point of 1 Mass % Aqueous Solution

The clouding point of a 1 mass % aqueous solution of each of the component (B) and the component (C) was measured as follows: 100 mL of the 1 mass % aqueous solution of the component to be subjected to the measurement was loaded into a beaker having a volume of 200 mL; while the aqueous solution was stirred with a magnetic stirrer (stirring bar length: 30 mm) under the condition of a rotational speed of 400 rpm, the aqueous solution was heated at a rate of temperature increase of 5° C./min until its temperature increased from 15° C. to its clouding point; and a liquid temperature when the appearance of the aqueous solution became cloudy was measured.

The “clouding point” of each of compounds shown in Table 1 and Table 2 below refers to the “clouding point of a 1 mass % aqueous solution” of the compound.

(2) HLB Value

A value calculated by Griffin's method was used as the HLB value of the component (A).

(3) Mass-average Molecular Weight

A mass-average molecular weight (Mw) was measured by using gel permeation chromatography (GPC). In the GPC, the measurement was performed by using two pieces of “TSKgel (trademark) SuperMultipore HZ-M” manufactured by Tosoh Corporation as columns, tetrahydrofuran as an eluent, and a refractive index detector as a detector, and the mass-average molecular weight (Mw) was determined by using polystyrene as a standard sample.

Examples 1 to 9 and Comparative Examples 1 to 6

The following respective components were mixed to prepare processing fluids having compositions shown in Table 1, and the processing fluids were subjected to evaluations described below.

The numerical values of blending composition in Table 1 are each represented in the unit of “mass %”.

The details of the respective components used in the preparation of the processing fluids having compositions shown in Table 1 are described below.

<Component (A)>

“Component (A)-1”

An EO adduct of 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol (EO adduct of an alkynediol, HLB=8)

“Component (A)-2”

A compound represented by the following formula (1) (EO adduct of a secondary alcohol)

<Component (B)>

“Component (B)-1”

A polyoxyalkylene alkyl ether including a polyoxyalkylene moiety formed of a random copolymer of ethylene oxide (EO) and propylene oxide (PO) (terminal methyl group (terminal alkyl group moiety), mass-average molecular weight (Mw)=4,597, EO/PO ratio (molar ratio)-42/58, clouding point of a 1 mass % aqueous solution=43° C.)

“Component (B)-2”

A poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide)-type block copolymer (mass-average molecular weight (Mw)=4,261, EO/PO ratio (molar ratio)=30/70, clouding point of a 1 mass % aqueous solution=38° C.)

“Component (B)-3”

A poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)-type block copolymer (clouding point of a 1 mass % aqueous solution=23° C.)

<Component (C)>

“Component (C)-1”

A poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)-type block copolymer (mass-average molecular weight (Mw)=5,654, EO/PO ratio (molar ratio)=48/52, clouding point of a 1 mass % aqueous solution=63° C.)

“Component (C)-2”

A poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)-type block copolymer (mass-average molecular weight (Mw)-5,498, EO/PO ratio (molar ratio)=52/48, clouding point of a 1 mass % aqueous solution=61° C.)

<Water>

• • Ion-exchanged water

<Other Components>

• • pH adjuster 1: isononanoic acid
  • pH adjuster 2: triisopropanolamine

[Evaluations]

The processing fluids of Examples and Comparative Examples were subjected to the following evaluations 1 to 3.

<Evaluation 1: Measurement of Silicon (Si) Friction Coefficient>

A friction coefficient was measured by performing a reciprocating kinematic friction test through use of each of the processing fluids, which had been obtained in Examples 1 to 9 and Comparative Examples 1 to 6, in accordance with the following test conditions.

• • Reciprocating kinematic friction testing machine: “F-2100” manufactured by Orientec Co., Ltd.

(Measurement Conditions)

• • Ball: 3/16 inch SUJ2
  • Test plate temperature: 50° C.
  • Test plate: polycrystalline silicon (mirror polished surface)·Sliding rate: 20 mm/sec
  • Sliding distance: 2 cm
  • Reciprocation number: 150 times
  • Load: 100 g

(Evaluation)

Such a processing fluid that the value of its friction coefficient was 0.20 or less was regarded as successful (rating A). In the case of an unsuccessful processing fluid, the processing fluid was rated as B.

<Evaluation 2: Evaluation by Processing with Multiwire Saw Apparatus>

The processing fluids of Examples 1 to 9 and Comparative Examples 1 to 4 were each subjected to an evaluation by processing with a multiwire saw apparatus.

(Test Conditions)

• • Test apparatus: multiwire saw apparatus
  • Wire: fixed abrasive grain wire core wire (wire diameter: 38 μm)
  • Workpiece: Si ingot for solar cell

(Evaluation Method)

The breakage ratio of the wires during the processing was evaluated. Specifically, the processing was performed 100 times (100 ingots were cut), and a case in which the number of times of breakage was less than 10 was regarded as successful (rating A). In the case of an unsuccessful processing fluid, the processing fluid was rated as B.

<Evaluation 3: Evaluation of Cleaning Property>

An evaluation was performed by using each of the processing fluids obtained in Examples 1 to 9 and Comparative Examples 1 to 6 in accordance with the following procedure.

(Evaluation of Contamination of Cylinder Wall Surface)

90 Milliliters of the processing fluid and 0.5 g of fine powder (“GRAPHITE POWDER”, manufactured by FUJIFILM Wako Pure Chemical Corporation, special grade) were loaded into a measuring cylinder having a volume of 100 mL. The measuring cylinder was lidded, and was vigorously shaken in a vertical direction 10 times, followed by the evaluation of the degree to which the upper portion of the inner wall of the measuring cylinder was contaminated based on the following criteria. A rating A was regarded as successful.

• • A: The degree to which the wall surface of the cylinder is contaminated with the fine powder is low, and hence a background near a liquid surface is seen through.
  • B: The degree to which the wall surface of the cylinder is contaminated with the fine powder is high, and hence a background near a liquid surface is not seen through.

The results of the evaluations 1 to 3 are shown in Table 1.

TABLE 1
			Example	Example	Example	Example	Example
			1	2	3	4	5
Processing	(A)-1	EO adduct of alkynediol	0.0350	0.0350	0.0350	0.0350	0.0350
fluid	(A)-2	EO adduct of secondary alcohol	—	—	—	—	—
(mass %)	(B)-1	Random copolymer of EO and PO Clouding	0.1390	—	—	0.1000	0.2200
*with		point of 1% aqueous solution: 43° C.
respect to	(B)-2	Block copolymer of EO and PO Clouding	—	0.1390	—	—	—
total		point of 1% aqueous solution: 38° C.
amount of	(B)-3	Block copolymer of EO and PO Clouding	—	—	0.1390	—	—
processing		point of 1% aqueous solution: 23° C.
fluid	(C)-1	Block copolymer of EO and PO Clouding	0.0200	—	—	—	—
		point of 1% aqueous solution: 63° C.
	(C)-2	Block copolymer of EO and PO Clouding	—	0.0200	0.0200	0.0200	0.0200
		point of 1% aqueous solution: 61° C.
	pH adjuster 1	Isononanoic acid	0.0008	0.0008	0.0008	0.0008	0.0008
	pH adjuster 2	Triisopropanolamine	0.0012	0.0012	0.0012	0.0012	0.0012
	Water	Ion-exchanged water	99.8040	99.8040	99.8040	99.8430	99.7230
		Total amount	100.000	100.000	100.000	100.000	100.000

Content	Content of component (A) (mass %) *with	18.0	18.0	18.0	22.6	12.7
and ratio	respect to effective components
of each	Total content of component (B) and	82.0	82.0	82.0	77.4	87.3
component	component (C) (mass %) *with
	respect to effective components
	(A)/(C) *mass ratio	1.750	1.750	1.750	1.750	1.750
	(B)/(C) *mass ratio	6.950	6.950	6.950	5.000	11.000
	(A)/{(B) + (C)} *mass ratio	0.220	0.220	0.220	0.292	0.146

Evaluation		pH	5.9	5.9	5.9	5.9	5.9
result	Evaluation 1	Si friction coefficient	0.16 A	0.16 A	0.17 A	0.17 A	0.15 A
	Evaluation 2	Multiwire saw processing/breakage ratio	A	A	A	A	A
	Evaluation 3	Cleaning property: contamination of	A	A	A	A	A
		cylinder wall surface

			Example	Example	Example	Example	Comparative
			6	7	8	9	Example 1
Processing	(A)-1	EO adduct of alkynediol	0.0350	0.0350	0.0200	0.0500	0.0350
fluid	(A)-2	EO adduct of secondary alcohol	—	—	0.0150	—	—
(mass %)	(B)-1	Random copolymer of EO and PO Clouding	0.1390	0.1390	0.1390	0.1390	—
*with		point of 1% aqueous solution: 43° C.
respect to	(B)-2	Block copolymer of EO and PO Clouding	—	—	—	—	—
total		point of 1% aqueous solution: 38° C.
amount of	(B)-3	Block copolymer of EO and PO Clouding	—	—	—	—	—
processing		point of 1% aqueous solution: 23° C.
fluid	(C)-1	Block copolymer of EO and PO Clouding	—	—	—	—	0.0200
		point of 1% aqueous solution: 63° C.
	(C)-2	Block copolymer of EO and PO Clouding	0.0200	0.0500	0.0200	0.0200	—
		point of 1% aqueous solution: 61° C.
	pH adjuster 1	Isononanoic acid	0.0008	0.0008	0.0008	0.0008	0.0008
	pH adjuster 2	Triisopropanolamine	0.0012	0.0012	0.0012	0.0012	0.0012
	Water	Ion-exchanged water	99.8040	99.7740	99.8040	99.7890	99.9780
		Total amount	100.000	100.000	100.000	100.000	100.000

Content	Content of component (A) (mass %) *with	18.0	15.6	18.0	23.9	63.6
and ratio	respect to effective components
of each	Total content of component (B) and	82.0	84.4	82.0	76.1	36.4
component	component (C) (mass %) *with
	respect to effective components
	(A)/(C) *mass ratio	1.750	0.700	1.750	2.500	1.750
	(B)/(C) *mass ratio	6.950	2.780	6.950	6.950	0.000
	(A)/{(B) + (C)} *mass ratio	0.220	0.185	0.220	0.314	1.750

Evaluation		pH	5.9	5.9	5.9	5.9	5.9
result	Evaluation 1	Si friction coefficient	0.16 A	0.17 A	0.17 A	0.15 A	0.16 A
	Evaluation 2	Multiwire saw processing/breakage ratio	A	A	A	A	B
	Evaluation 3	Cleaning property: contamination of	A	A	A	A	A
		cylinder wall surface

			Comparative	Comparative	Comparative	Comparative	Comparative
			Example 2	Example 3	Example 4	Example 5	Example 6
Processing	(A)-1	EO adduct of alkynediol	0.0350	0.0350	0.0350	—	0.0040
fluid	(A)-2	EO adduct of secondary alcohol	—	—	—	—	—
(mass %)	(B)-1	Random copolymer of EO and PO Clouding	0.0050	0.0500	—	0.1390	0.1390
*with		point of 1% aqueous solution: 43° C.
respect	(B)-2	Block copolymer of EO and PO Clouding	—	—	—	—	—
to total		point of 1% aqueous solution: 38° C.
amount of	(B)-3	Block copolymer of EO and PO Clouding	—	—	—	—	—
processing		point of 1% aqueous solution: 23° C.
fluid	(C)-1	Block copolymer of EO and PO Clouding	0.0200	—	0.1900	0.0200	0.0200
		point of 1% aqueous solution: 63° C.
	(C)-2	Block copolymer of EO and PO Clouding	—	—	—	—	—
		point of 1% aqueous solution: 61° C.
	pH adjuster 1	Isononanoic acid	0.0008	0.0008	0.0008	0.0008	0.0008
	pH adjuster 2	Triisopropanolamine	0.0012	0.0012	0.0012	0.0012	0.0012
	Water	Ion-exchanged water	99.9730	99.9480	99.8080	99.8390	99.8390
		Total amount	100.000	100.000	100.000	100.000	100.000

Content	Content of component (A) (mass %) *with	58.3	41.2	15.6	0.00	2.45
and ratio	respect to effective components
of each	Total content of component (B) and	41.7	58.8	84.4	100.0	97.5
component	component (C) (mass %) *with
	respect to effective components
	(A)/(C) *mass ratio	1.750	—	0.184	0.000	0.200
	(B)/(C) *mass ratio	0.250	—	0.000	6.950	6.950
	(A)/{(B) + (C)} *mass ratio	1.400	0.700	0.184	0.000	0.025

Evaluation		pH	5.9	5.9	5.9	5.9	5.9
result	Evaluation 1	Si friction coefficient	0.16 A	0.15 A	0.35 B	0.22 B	0.21 B
	Evaluation 2	Multiwire saw processing/breakage ratio	B	B	A	—	—
	Evaluation 3	Cleaning property: contamination of	A	B	A	B	B
		cylinder wall surface

The following is found from Table 1.

It is found that in each of the processing fluids of Examples 1 to 9, the breakage ratio is low, the silicon (Si) friction coefficient shows an appropriate value, and the cleaning property is excellent.

In contrast, it is found that the processing fluids of Comparative Examples 1 to 3 each have a high breakage ratio.

In addition, it is found that in each of the processing fluids of Comparative Examples 4 to 6, the silicon (Si) friction coefficient is high, and hence does not show an appropriate value.

Further, it is found that the processing fluids of Comparative Examples 3, 5, and 6 are each poor in cleaning property.