JP2009062426A - Water-soluble working fluid for loose grain wire saw, slurry, and cutting work method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-soluble working fluid for a loose abrasive grain wire saw for obtaining good cutting precision without causing a crack, that is, drop of a part of a wafer from a slicing table during cutting or after cutting when a silicon wafer is cut out from an ingot by using a loose grain wire saw and to provide slurry containing the working fluid and loose abrasive grain and a brittle material cutting work method using the slurry. <P>SOLUTION: The water-soluble working fluid for a loose abrasive grain wire saw comprises (A) propylene glycol, (B) diethylene glycol, (C) dicarboxylate, (D) an alkylene oxide addition product of alkylene glycol, and (E) water. In the water-soluble working fluid for a loose abrasive grain wire saw, a compounding amount of (B) diethylene glycol is 1.50-1.80 times of that of (A) propylene glycol. The slurry for cutting work contains the working fluid and abrasive grain. In the working method of a brittle material, the brittle material is cut by using the slurry. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a water-soluble processing oil for a loose abrasive wire saw, a slurry, and a cutting method using the same. More specifically, when a brittle material is cut with a wire saw, a water-soluble processing oil used for preparing a slurry containing an oil supplied to the material to be cut and free abrasive, the oil and free abrasive included The present invention relates to a slurry to be cut and a method for cutting a brittle material using the slurry.

In the cutting of brittle materials with high hardness, wire saws and blade saws (band saws) using loose abrasive grains have been widely used in recent years from the viewpoint of processing efficiency and processing accuracy. In that case, the liquid (slurry) which mixed and adjusted the abrasive grain and the oil agent is generally used.
For example, (A) at least one compound selected from the group consisting of polyhydric alcohols, polyhydric alcohol condensates, and polyhydric alcohol derivatives, (B) aromatic polyvalent carboxylates, (C) alkylene glycols A water-soluble cutting oil containing water containing an oxide adduct and water has been proposed (Patent Document 1).
In order to reduce kerf loss when cutting silicon wafers from ingots when cutting brittle materials such as silicon using loose abrasive wire saws, the grain size of abrasives has recently been reduced to # 1000. From # 1500 to # 2500. In that case, a phenomenon of “cracking” in which a part of the wafer falls from the slicing table is likely to occur during or after cutting.

JP2006-96951

An object of the present invention is to provide a water-soluble processing oil for a free-abrasive wire saw that is free from the above-mentioned problem of “cracking” and that provides excellent cutting accuracy.
Another object of the present invention is to provide a slurry containing the above oil agent and free abrasive grains.
Still another object of the present invention is to provide a brittle material cutting method using the above-mentioned oil agent and slurry.

  As a result of diligent studies to solve the above-mentioned problems, the present inventors have found that when the ratio of diethylene glycol increases in an oil agent containing propylene glycol, diethylene glycol, dicarboxylate, alkylene oxide adduct of alkylene glycol and water, When the peel load decreases and the risk of occurrence of “cracking” decreases, the ratio of propylene glycol increases. On the contrary, by improving the cutting ability and adjusting the addition amount of alkylene oxide adduct of alkylene glycol, “cracking” It has been found that the occurrence of "can be significantly reduced, and the present invention has been completed.

The present invention provides the following water-soluble processing oil for free abrasive wire saw, slurry, and a cutting method using the same.
1. (A) Propylene glycol, (B) diethylene glycol, (C) dicarboxylate, (D) an alkylene oxide adduct of alkylene glycol, and (E) a water-soluble processing oil for a free abrasive grain wire saw,
(A) A water-soluble processing oil for a free abrasive grain wire saw, wherein the blending amount of (B) diethylene glycol is 1.50 to 1.80 times the blending amount of propylene glycol.
2. (A) 30 to 33% by mass of propylene glycol, (B) 45 to 59% by mass of diethylene glycol, (C) 0.5 to 10% by mass of dicarboxylate, and (D) 2 to 10% by mass of an alkylene oxide adduct of alkylene glycol. (E) The water-soluble processing oil for a free abrasive wire saw according to the above 1, which contains 5 to 22.5% by mass of water.
3. (C) The water-soluble processing oil for free abrasive wire saws according to 1 or 2 above, wherein the dicarboxylate is a salt of a dicarboxylic acid having 8 to 20 carbon atoms and an alkanolamine.
4). (D) The water-soluble processing oil for free abrasive wire saws according to any one of 1 to 3 above, wherein the alkylene oxide adduct of alkylene glycol has a molecular weight of 500 to 5000.
5). 5. A slurry for cutting work comprising the water-soluble processing oil for a free abrasive grain wire saw according to any one of 1 to 4 and abrasive grains.
6). 6. A method for processing a brittle material, comprising cutting the brittle material using the slurry according to 5 above.
7). 7. The method according to 6 above, wherein the brittle material is a silicon brittle material.
8). 8. A silicon-based brittle material processed by the brittle material processing method described in 6 or 7 above.

  The water-soluble processing oil agent in which the blending amount of (B) diethylene glycol with respect to the blending amount of (A) propylene glycol of the present invention is a specific ratio is a slurry as compared with the case where an oil agent outside the above specified ratio range is used. Excellent dispersion stability of the abrasive grains, adhesion of the abrasive grains to the cutting wire (riding), releasability, and cutting performance. As a result, the cutting efficiency is high and the accuracy of the cut surface is excellent. Also, in the cleaning process for removing the slurry after cutting, it can be easily washed with water without using a solvent, etc., and there is no concern about flammability. Can be easily cleaned, and does not deteriorate the work environment, contributing to the improvement of productivity.

In the oil of the present invention, the blending amount of (B) diethylene glycol is 1.50 to 1.80 times the blending amount of (A) propylene glycol. Outside this range, the phenomenon of “cracking” in which a portion of the wafer falls from the slicing table tends to occur, and the adhesiveness (ride) of the abrasive grains to the cutting wire tends to be poor.
In the oil agent of the present invention, the content of component (A) propylene glycol is preferably 30 to 33% by mass. If it is less than 30% by mass, the adhesiveness (riding) of the abrasive grains to the cutting wire tends to be inferior, and if it exceeds 33% by mass, “cracking” tends to occur.
In the oil agent of the present invention, the content of component (B) diethylene glycol is preferably 45 to 59% by mass. If it is less than 45% by mass, “cracking” tends to occur, and if it exceeds 59% by mass, the adhesiveness (riding) to the cutting wire tends to be poor.

The dicarboxylic acid salt of component (C) used in the present invention contributes to the dispersibility and redispersibility of the abrasive grains and the adhesiveness of the abrasive grains to the wire when made into a slurry. Preferable examples of the dicarboxylic acid salt used in the present invention include a salt of a dicarboxylic acid having 8 to 20 carbon atoms and an alkanolamine having 2 to 12 carbon atoms. The dicarboxylic acid is preferably an aromatic dicarboxylic acid, and specific examples include phthalic acid, isophthalic acid, and terephthalic acid. Specific examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, monomethylethanolamine, diethylethanolamine and the like.
The solubility of the dicarboxylate used in the present invention in water is desirably 5 g / 100 g water or more at 20 ° C. If it is less than 5 g / 100 g water, the dicarboxylate is easily broken out, which is not preferable.
In the oil agent of the present invention, the content of the dicarboxylate is preferably 0.5 to 10% by mass, more preferably 0.5 to 5% by mass, and most preferably 0.5 to 2% by mass. If it is less than 0.5% by mass, the effect of improving the dispersibility of the abrasive grains in the slurry is not sufficient, and if it exceeds 10% by mass, the effect of improving the dispersibility is saturated, which is economically disadvantageous.

Examples of the alkylene oxide adduct of alkylene glycol of component (D) used in the present invention include ethylene oxide and / or propylene oxide adduct of ethylene glycol and / or propylene glycol. The number of added moles is preferably 5 to 100, more preferably 10 to 80, and the molecular weight is preferably 500 to 5000, more preferably 1000 to 2000.
The solubility of the alkylene oxide adduct of alkylene glycol in water is desirably 5 g / 100 g water or more.
In the oil agent of the present invention, the content of the alkylene oxide adduct of the alkylene glycol of component (D) is preferably 2 to 10% by mass, more preferably 3 to 10% by mass. If the content is less than 2% by mass, the effect of improving the adhesion of abrasive grains to the wire is low, and even if the content exceeds 10% by mass, the effect is saturated and uneconomical.

  Examples of work materials suitable for cutting using the oil agent of the present invention include brittle materials widely used in the electronics industry, and specific examples include silicon (single crystal, polycrystalline ), Semiconductors such as gallium arsenide, ceramics such as alumina and zirconium oxide, and glass such as quartz glass and silicate glass. When the brittle material is silicon-based, the pH of the oil is preferably 5-9. In this case, as the basic substance, it is desirable to use an organic basic substance rather than an inorganic basic substance. In particular, tertiary mild alkanolamines such as basic mild triethanolamine and triisopropanolamine are desirable.

  As water used for the oil agent of the present invention, any of ultrapure water, distilled water, ion exchange water, tap water, city water, industrial water, etc. may be used, and the water content is preferably 5-22. 5% by mass. When the water content exceeds 22.5% by mass, the viscosity of the slurry becomes too low, and the cutting performance may be deteriorated. If it is less than 5% by mass, the water in the slurry (water in the oil) evaporates due to the generation of heat during the cutting process, and the oil itself may become flammable and lose its properties as a water-soluble oil. .

The oil agent of the present invention can be easily produced by mixing and dissolving the components (A) to (E) under an appropriate temperature condition, for example, at about 40 to 70 ° C. At that time, if necessary, a surfactant (anionic or nonionic), a water-soluble thickener, a preservative, a fungicide, a non-ferrous metal anticorrosive, a pH buffer, or the like may be appropriately added and contained.
The oil agent of the present invention is usually an oil agent and abrasive grains (for example, GC green silicon carbide abrasive grains) in a mass ratio of oil agent: abrasive grains = 1.0: 0.8 to 1.0: 1.5 (for example, 1. 0: 0.9) and used as a slurry for cutting a brittle material.

EXAMPLES Hereinafter, although the water-soluble oil agent of this invention is demonstrated in detail by an Example and a comparative example, this invention is not limited to these.
1. Method for measuring properties of oil
(a) pH measurement Each oil agent was diluted twice with ion-exchanged water and measured by the JIS-Z-8802 glass electrode method.
2. Slurry Property Measurement Test Method Slurries of each oil agent (mass ratio: oil agent: GC # 1500 abrasive grains = 1.0: 0.9) were measured by the following test conditions and test methods.
(a) Abrasive dispersion stability test Each oil slurry was transferred to a 100 ml graduated cylinder and allowed to stand at room temperature for 12 hours, and the abrasive dispersion stability was observed with the naked eye.
Evaluation was according to the following criteria.
○: Separation oil content less than 10 ml ×: Separation oil content more than 10 ml
(b) Abrasive adhesion to wire The wire is immersed in a slurry placed in a test vessel for 5 seconds, then pulled up and left in a vertical state for 10 seconds, and then evaluated by observing with a microscope.
Evaluation was according to the following criteria.
○: Abrasive grains are well adhered on the wire ×: Abrasive grains are slightly adhered on the wire-Almost not adhered

(c) Peelability test A silicon wafer (Silicon Wafer diameter: 3 inches, thickness: 0.8 mm) is dipped in each oil slurry and left vertically for 15 minutes. Next, the overlapping position of these two wafers is slightly shifted, and the weight is leveled and stacked for 16 hours. After 16 hours, the two stacked wafers are hung vertically with a double clip, and 10 g is weighted on each wafer step by step, and the load when the stacked wafers are peeled off is recorded.
Evaluation was according to the following criteria.
○: Peeling load 10 g or less (hard to break)
×: Peeling load 20g or more (easy to break)

(d) Cutting property test Cutting was performed with a 3-inch ingot cutting wire saw.
Cutting device: Multi-wire saw MS-34 (manufactured by Takatori)
Cutting material: Single crystal silicon ingot material Dimensions: Φ3 inch x 60mmL
Wire diameter: 0.14mm
Wire speed: 200mm / min
New line supply: 8m / min
In the evaluation, the warp (swell) of the processed surface was measured. Warp indicates that the smaller the value, the better the machining accuracy.
Evaluation 7 μm or less: Pass (○)
Over 7 μm: Fail (×)

Comprehensive evaluation
Pass (○): When all are ○ Fail (×): When there is × The results are shown in Tables 1 and 2.

* 1: Alkylene oxide adduct A of alkylene glycol:
Ethylene glycol adduct with ethylene oxide (molecular weight 1000)
* 2: Alkylene oxide adduct B of alkylene glycol:
Ethylene oxide adduct of propylene glycol (molecular weight 2000)
* 3: Alkylene oxide adduct C of alkylene glycol C:
Ethylene glycol ethylene oxide / propylene oxide adduct (2000 molecular weight)
Isophthalic acid triethanolamine salt is a 1: 2 molar ratio of isophthalic acid to triethanolamine

Comparative Examples 6 and 7 are commercially available water-soluble cutting oils.
(A) The slurry of Examples 1 to 5 of the present invention in which the blending amount of (B) diethylene glycol is within the range of 1.50 to 1.80 times the blending amount of propylene glycol is dispersion stability, abrasive grain adhesion, Excellent peelability and cutting performance.
(A) The slurry of Comparative Examples 1 and 2 in which the blending amount of (B) diethylene glycol is less than 1.50 times the blending amount of propylene glycol is excellent in dispersion stability, abrasive adhesion, and cutting ability. The peelability is inferior.
(A) Slurries of Comparative Examples 3 and 4 in which the blending amount of (B) diethylene glycol exceeds 1.80 times with respect to the blending amount of propylene glycol have excellent peelability, but dispersion stability, abrasive adhesion, and cutting The sex is inferior.
(D) Although the slurry of the comparative example 5 which does not contain the alkylene oxide adduct of alkylene glycol is excellent in peelability, it is inferior in dispersion stability, adhesiveness to abrasive grains, and cutting ability.
Slurries using commercially available oil agents are inferior in dispersion stability, adhesiveness to abrasive grains, peelability and cutting ability.

Claims (8)

(A) Propylene glycol, (B) diethylene glycol, (C) dicarboxylate, (D) an alkylene oxide adduct of alkylene glycol, and (E) a water-soluble processing oil for a free abrasive grain wire saw,
(A) A water-soluble processing oil for a free abrasive grain wire saw, wherein the blending amount of (B) diethylene glycol is 1.50 to 1.80 times the blending amount of propylene glycol. (A) 30 to 33% by mass of propylene glycol, (B) 45 to 59% by mass of diethylene glycol, (C) 0.5 to 10% by mass of dicarboxylate, and (D) 2 to 10% by mass of an alkylene oxide adduct of alkylene glycol. (E) The water-soluble processing oil agent for free-abrasive wire saws of Claim 1 containing 5-22.5 mass% of water. The water-soluble processing oil for free abrasive wire saws according to claim 1 or 2, wherein (C) the dicarboxylic acid salt is a salt of a dicarboxylic acid having 8 to 20 carbon atoms and an alkanolamine. (D) The molecular weight of the alkylene oxide adduct of alkylene glycol is 500-5000, The water-soluble processing oil for free abrasive wire saws of any one of Claims 1-3.   The slurry for cutting process containing the water-soluble processing oil agent for free abrasive grain wire saws and abrasive grain of any one of Claims 1-4.   A method for processing a brittle material, comprising cutting the brittle material using the slurry according to claim 5.   The method according to claim 6, wherein the brittle material is a silicon-based brittle material.   A silicon-based brittle material processed by the method for processing a brittle material according to claim 6 or 7.