JP5350839B2 - Processing oil for brittle materials and processing oil composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing oil for brittle materials in which the inflammability is low and the dispersion stability of the abrasive grains is excellent, and to provide a processing oil composition which comprises blending abrasive grains with the same. <P>SOLUTION: The processing oil for brittle materials includes a polyhydric alcohol-based compound as a base oil, and is produced by blending, based on the total amount of the processing oil, 0.5 to 30 mass% of an ionic surfactant having a mass average molecular weight of 500 or more; 0.1 to 10 mass% of a metal acid salt; and 5 to 50 mass% of water. The processing oil composition made by blending an abrasive grain with the processing oil for brittle materials has low inflammability and is excellent also in the dispersion stability of the abrasive grains. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a processing oil for brittle materials and a processing oil composition obtained by blending abrasive grains with the processing oil. Specifically, the present invention relates to a processing oil and processing oil composition for a brittle material used when a brittle material such as silicon or ceramics is cut with a wire saw.

  In the manufacture of semiconductor products, it is necessary to cut a silicon ingot that is a brittle material, and wire saw processing is generally used from the viewpoint of processing accuracy and productivity. In wire saw processing, a slurry in which free abrasive grains are dispersed in processing oil is used, and a brittle material is cut by a wire saw made of piano wire or the like. As the processing oil, a water-insoluble oil agent mainly composed of mineral oil is mainly used. Specifically, the ingot is cut while supplying a slurry-like cutting fluid in which abrasive grains such as SiC are mixed and dispersed in the processing oil to the blade portion of the ingot cutting device.

However, since the conventional processing oil mainly composed of mineral oil is a flammable dangerous material, the storage quantity is limited by the Fire Service Act. Further, the waste liquid needs to be treated so as not to cause environmental problems.
Accordingly, various water-soluble processing oils have been proposed instead of water-insoluble processing oils mainly composed of mineral oil. For example, an aqueous cutting fluid is disclosed in which abrasive grains are dispersed in a dispersion medium composed of a hydrophilic polyhydric alcohol compound such as ethylene glycol, a lipophilic polyhydric alcohol compound such as propylene glycol, and water ( Patent Document 1). Also disclosed is an abrasive dispersion medium composition for cutting an ingot that contains water, a nonionic surfactant, and bentonite in a mineral oil base oil or a synthetic base oil, and does not contain a predetermined fatty acid ester (patent). Reference 2).

JP 11-302681 A Japanese Patent Application Laid-Open No. 11-100590

  However, although the aqueous processing oil composition for cutting silicon ingots disclosed in Patent Documents 1 and 2 has low flammability, it is difficult to say that the state of the slurry in which abrasive grains are dispersed is necessarily stable. That is, the abrasive grains tend to settle and it is difficult to stably cut the silicon ingot.

  Accordingly, an object of the present invention is to provide a processing oil for brittle materials having low flammability and excellent abrasive dispersion stability, and a processing oil composition obtained by blending abrasive grains therein.

  In order to solve the above-described problems, the present invention provides the following processing oil for brittle materials and a processing oil composition obtained by blending abrasive grains with the processing oil.

(1) A processing oil for a brittle material having a polyhydric alcohol compound as a base oil, and 0.5 to 30% by mass of a surfactant having a mass average molecular weight of 500 or more based on the total amount of the processing oil, a metal acid A processing oil for brittle materials comprising 0.1 to 10% by mass of salt and 5 to 50% by mass of water.
(2) The processing oil for brittle materials according to the above (1), wherein the polyhydric alcohol compound is at least one of alkylene glycol and polyalkylene glycol.
(3) In the processing oil for brittle materials described in (1) above, the polyhydric alcohol compound is at least one of an alkylene glycol derivative and a polyalkylene glycol derivative, and each derivative is at least one of hydroxyl groups. A processing oil for brittle materials, wherein the part has a structure bonded to a hydrocarbyl group by an ether bond or an ester bond.
(4) The brittle material processing oil according to any one of (1) to (3) above, wherein the surfactant is an ionic surfactant. .
(5) The processing oil for brittle materials according to the above (4), wherein the ionic surfactant is a polycarboxylic acid or a salt thereof.
(6) In the processing oil for brittle material according to any one of (1) to (5) above, further, among rust preventives, antifoaming agents, metal deactivators and pH adjusters, A processing oil for brittle materials, comprising at least one of them.
(7) A processing oil composition comprising abrasive grains blended with the processing oil for brittle materials according to any one of (1) to (6) above.

  ADVANTAGE OF THE INVENTION According to this invention, the processing oil composition which mix | blends an abrasive grain with this and the processing oil for brittle materials which has water, is low in flammability, and has the outstanding abrasive grain dispersibility are provided.

The processing oil for brittle materials of the present invention is obtained by blending a surfactant having a mass average molecular weight of 500 or more, a metal acid salt, and water with a polyhydric alcohol compound as a base oil.
As the polyhydric alcohol compound used in the present invention, alkylene glycol and polyalkylene glycol are preferably used from the viewpoint of water solubility and processability. As the alkylene glycol, propylene glycol and ethylene glycol having a low molecular weight and low viscosity are preferable from the viewpoint of processability, but other alkylene glycols are not particularly problematic as long as the molecular weight is 100 or less. From the viewpoint of the metal salt dispersion effect, propylene glycol is more preferable than ethylene glycol.
Moreover, if the molecular weight is 400 or less, polyalkylene glycol such as polyethylene glycol may be used.
Furthermore, the polyhydric alcohol compound may be an alkylene glycol derivative or a polyalkylene glycol derivative. Specifically, a structure in which at least a part of the hydroxyl group is bonded to the hydrocarbyl group by an ether bond or an ester bond may be used. Examples of the hydrocarbyl group include an alkyl group.

  The surfactant used in the processing oil for brittle materials of the present invention is any of an ionic surfactant, an amphoteric surfactant (a zwitterionic surfactant), and a nonionic surfactant (a nonionic surfactant). But you can. Examples of the nonionic surfactant include a block copolymer of propylene oxide and ethylene oxide, polyalkylene glycol and derivatives thereof.

  In these, an ionic surfactant is preferable at the point of the dispersion effect of an abrasive grain. The ionic surfactant is roughly classified into an anionic surfactant in which a hydrophilic portion (hydrophilic group) can be an anion and a cationic surfactant in which a hydrophilic group can be a cation. Examples of the hydrophilic group of the anionic surfactant include those having a carboxylic acid, sulfonic acid, or phosphoric acid structure. Moreover, what has a tetraalkylammonium structure is mentioned as a hydrophilic group of a cationic surfactant. In the case of an anionic surfactant, the hydrophilic group may be a free acid, but a salt such as a sodium salt or potassium salt is preferred from the viewpoint of improving the dispersibility of the abrasive grains.

  In the present invention, among the above-mentioned surfactants, an anionic surfactant is most preferable in terms of the effect of dispersing abrasive grains. In particular, those known as polycarboxylic acids (salts) can be suitably used. For example, non-crosslinked polymer polycarboxylic acid (salt) is preferably used. Such a non-crosslinked polymer polycarboxylic acid (salt) may be a homopolymer of a monomer having a carboxyl group, and a monomer having a carboxyl group and two or more other monomers having a carboxyl group or a carboxyl It may be a copolymer with two or more other monomers having no group. Examples of the homopolymer include poly (meth) acrylic acid or a salt thereof, polycrotonic acid or a salt thereof, polyitaconic acid or a salt thereof, and the like. Examples of the copolymer of a monomer having a carboxyl group and two or more other monomers having a carboxyl group include, for example, a (meth) acrylic acid-maleic acid copolymer or a salt thereof, an acrylic acid-crotonic acid copolymer, or The salt, acrylic acid-sulfonic acid copolymer, or its salt is mention | raise | lifted. Examples of the copolymer of a monomer having a carboxyl group and two or more other monomers having no carboxyl group include an ethylene-maleic acid copolymer or a salt thereof, a methacrylic acid-ethyl acrylate copolymer or a salt thereof. Can be mentioned. Among these, an acrylic acid / maleic acid copolymer is particularly preferable, and the copolymerization ratio (molar ratio) is 75/25 to 50/50. Examples of the salt include sodium salt and potassium salt, but sodium salt is preferable. Moreover, the non-crosslinked polymer polycarboxylic acid (salt) to be used can be used alone or in combination.

The above-mentioned surfactant has a mass average molecular weight of 500 or more, preferably 1000 or more, more preferably 3000 or more. When the weight average molecular weight is less than 500, the abrasive grain dispersion effect is inferior when the abrasive grains are blended with the processing oil. On the other hand, if the weight average molecular weight of the surfactant exceeds 100,000, the viscosity of the processing oil becomes too high, which may adversely affect the processing accuracy and processing rate during wire saw processing. Therefore, the weight average molecular weight of the surfactant is preferably 100,000 or less, and more preferably 10,000 or less. Such a mass average molecular weight may be measured, for example, by gel permeation chromatography.
Moreover, although the compounding quantity of surfactant mentioned above is 0.5-30 mass% on the basis of processing oil whole quantity basis, Preferably it is 1-20 mass%. When the amount of the surfactant is less than 0.5% by mass, the effect of dispersing the abrasive grains is inferior. On the other hand, when the compounding amount of the above-described surfactant exceeds 30% by mass, the viscosity is excessively increased and the processability is poor.

The metal acid salt used in the processing oil for brittle materials of the present invention has an effect of redispersing abrasive grains that have settled in the processing oil in the processing oil. Examples of metal salts having such effects include aluminate, antimonate, uranate, sodium chloride chloride, sodium chromate, lead chromate, stannate, sodium tansugate, ammonium vanadate, Examples include ammonium molybdate, sodium molybdate, and potassium silicate.
One or more of these metal acid salts can be used alone or in combination, but the blending amount is 0.1 to 10% by mass, preferably 0.5 to 5% by mass, based on the total amount of processing oil. . If the blending amount is less than 0.1% by mass, the effect is low, and if it exceeds 10% by mass, precipitation tends to occur in the processing oil.

  The water blended in the processing oil for brittle materials of the present invention is an essential component for reducing flammability and may be tap water, but water containing no impurities such as distilled water or ion-exchanged water is preferred. The amount of water blended is 5 to 50% by mass, preferably 10 to 30% by mass, based on the total amount of processing. If the blending amount of water is less than 5% by mass, flammability may occur. On the other hand, if the blending amount of water exceeds 50% by mass, abrasive grains are added to the processing oil to provide a processing oil composition ( When using as an aqueous cutting fluid, the dispersibility of the abrasive grains may be significantly reduced.

Furthermore, you may mix | blend a rust preventive agent, an antifoamer, a metal deactivator, a pH adjuster, etc. with the aqueous brittle material processing oil of this invention in the range which does not impair the effect of invention.
Examples of the rust inhibitor include alkyl benzene sulfonate, dinonyl naphthalene sulfonate, alkenyl succinate, polyhydric alcohol ester and the like. As a compounding quantity, about 0.01-5 mass% is preferable on the basis of electric discharge machining oil whole quantity.
Examples of the antifoaming agent include silicone oil, fluorosilicone oil, and fluoroalkyl ether. As a compounding quantity, about 0.01-5 mass% is preferable on the basis of electric discharge machining oil whole quantity.

  The metal deactivator is mainly used as a copper corrosion inhibitor, and examples thereof include benzotriazole, imidazoline, pyrimidine derivatives, and thiadiazole. One of these may be used alone, or two or more may be used in combination. The blending amount is preferably about 0.01 to 1% by mass based on the total amount of electric discharge machining oil. As an electrode of an electric discharge machine, copper is usually used, so by adding a metal deactivator in the above range, as an oxidation catalyst for metal oxides such as copper mixed in a small amount in electric discharge machining oil. Can be suppressed.

  The pH adjuster functions to stably disperse the abrasive grains in the processing oil. The preferable pH adjustment range as a processing oil composition which mix | blended the abrasive grain is 4-12, Preferably it is 4-11, More preferably, it is 5-10. If the pH is less than 4, rust prevention may be deteriorated, and if the pH is higher than 12, silicon may be corroded. Examples of such a pH adjuster include organic acids such as acetic acid, malic acid, and citric acid, salts thereof, phosphoric acid, and salts thereof.

  As described above, the brittle material processing oil of the present invention contains a predetermined surfactant, metal acid salt, and water, with a predetermined polyhydric alcohol as a base oil. The resulting processing oil composition (slurry) has low flammability and has excellent abrasive dispersibility and abrasive redispersibility. Therefore, the processing oil composition of the present invention is suitably used when a brittle material is processed with a wire saw or a multi-wire saw. Examples of the brittle material include silicon, quartz, ceramics, and carbon. As an abrasive grain, it can use without a restriction | limiting especially, For example, a SiC (silicon carbide) abrasive grain, an alumina abrasive grain, a diamond abrasive grain etc. are mentioned. The blending amount of the free abrasive grains can be appropriately determined according to the purpose. Usually, the processing oil for brittle materials: free abrasive grains is 95: 5 to 10:90, preferably 90:10 to 30:70 by mass ratio. is there.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

[Examples 1-5, Comparative Examples 1-6]
Using the following base oils and additives, processing oils (sample oils) having the composition shown in Table 1 were prepared, and abrasive grains were further blended for various evaluations. The evaluation results are also shown in Table 1.

(Base oil)
(1) Propylene glycol
(2) Polyethylene glycol 200
Ethylene oxide adduct to ethylene oxide (both terminal hydroxyl groups, number average molecular weight: 200)
(3) Ethylene glycol

(Additive)
(1) Sodium polyacrylate (mass average molecular weight 5,000)
Nippon Shokubai Aquaric DL365
(2) Acrylic acid / maleic acid copolymer salt (mass average molecular weight 5,000)
Nippon Shokubai Aquaric TL37
(3) Sodium tantsugtenate dihydrate
(4) Sodium molybdate dihydrate
(5) Potassium silicate Nippon Chemical Industry B potassium silicate
(6) Citric acid
(7) Water (distilled water)

(Abrasive grains)
GC1000 and GC3000, which are abrasive grains manufactured by Fujimi Incorporated, were used. Both are abrasive grains mainly composed of silicon carbide (SiC) and have different average particle diameters.

(Evaluation method)
(1) Viscosity at the time of mixing abrasive grains The test oil and abrasive grains were mixed at 1: 1 (mass ratio), and immediately after becoming a slurry state, a B-type rotational viscometer (TVB-10 manufactured by Toki Sangyo) was used. And measured at 25 ° C.
(2) pH
The pH of the slurry obtained in (1) above was measured at 25 ° C. using a commercially available pH meter.

(3) Abrasive dispersion stability test 100 ml of the slurry of (1) above (immediately after mixing) was placed in a cylinder (inner diameter: 28 mm) having an internal volume of 120 ml and left in an atmosphere at 30 ° C. After 5 hours, the ratio of the liquid separation layer (layer in which the abrasive grains and the test oil were separated) to the total liquid was determined. Specifically, the ratio (%) of the liquid separation layer was calculated by the following formula.
Ratio of liquid separation layer (%) = (volume of liquid separation layer (ml) / total volume (ml)) × 100
(4) Flowability test of precipitated abrasive grains
The cylinder after being allowed to stand for 24 hours under the same conditions as the abrasive dispersion stability test of (3) was inverted. Then, the volume of the accumulated abrasive grains was measured after 1 hour.

(Evaluation results)
From the results of Examples 1 to 5 in Table 1, the water-soluble brittle material processing oil of the present invention is blended with a predetermined amount of a predetermined surfactant, metal acid salt and water using a predetermined polyhydric alcohol compound as a base oil. Therefore, the dispersion stability of the abrasive grains is excellent. In addition, after the stirring of the slurry is stopped, the redispersibility of the settled abrasive grains is excellent. Therefore, it can be understood that the processing accuracy and processing efficiency at the time of wire saw processing are high and the workability is also excellent. In particular, it should be noted that the dispersion stability of the abrasive grains is excellent while using a low-viscosity base oil such as propylene glycol or polyethylene glycol 200. On the other hand, in Comparative Examples 1 to 6 in Table 1, since any of the additives essential in the present invention is lacking, all are inferior in the dispersion stability of the abrasive grains. In Comparative Examples 3 to 5 which lack both the predetermined surfactant and the metal acid salt, the redispersibility of the abrasive grains is very poor. In addition, both Example 2 and Comparative Example 2 are a system in which very fine abrasive grains (GC3000) are blended to form a slurry, but in Comparative Example 2, because a predetermined surfactant is not blended, Dispersion stability of abrasive grains Inferior to Example 1.

  The processing oil for brittle materials of the present invention is suitably used for wire saw processing of brittle materials (silicon ingot, crystal, ceramics, etc.) as a processing oil composition in which abrasive grains are blended.

Claims (7)

A processing oil for brittle materials based on a polyhydric alcohol compound,
0.5 to 30% by mass of a surfactant having a mass average molecular weight of 500 or more, 0.1 to 10% by mass of a metal acid salt, and 5 to 50% by mass of water, based on the total amount of the processing oil. A processing oil for brittle materials. In the processing oil for brittle materials according to claim 1,
The brittle material processing oil, wherein the polyhydric alcohol compound is at least one of alkylene glycol and polyalkylene glycol. In the processing oil for brittle materials according to claim 1,
The polyhydric alcohol compound is at least one of an alkylene glycol derivative and a polyalkylene glycol derivative;
Each of the derivatives has a structure in which at least a part of a hydroxyl group is bonded to a hydrocarbyl group by an ether bond or an ester bond. In the processing oil for brittle materials according to any one of claims 1 to 3,
The processing oil for brittle materials, wherein the surfactant is an ionic surfactant. In the processing oil for brittle materials according to claim 4,
The brittle material processing oil, wherein the ionic surfactant is a polycarboxylic acid or a salt thereof. In the processing oil for brittle materials according to any one of claims 1 to 5,
Furthermore, the processing oil for brittle materials characterized by mix | blending at least any 1 type in a rust preventive agent, an antifoamer, a metal deactivator, and a pH adjuster. In the processing oil for brittle materials according to any one of claims 1 to 6,
A processing oil composition comprising abrasive grains.