KR20110015192A - Aqueous sawing fluid composition for wire saw - Google Patents

Abstract

PURPOSE: An aqueous sawing fluid composition for wire saw is provided to minimize the used amount because of no thickening of viscosity by cutting particles and to remove cutting residues of abrasives or products. CONSTITUTION: An aqueous sawing fluid composition for wire saw includes, based on the total weight of the composition, 1-40 weight% of cyclohexanedimethanol or dimethylolpropane. The composition comprises glycol compounds. The glycol compounds are included in the amount of 50-99 weight%. The composition further includes 1-40 weight% of water. The water-soluble slurry for processing comprises the aqueous sawing fluid composition for wire saw and abrasive grains.

Description

Aqueous sawing fluid composition for wire saw

The present invention relates to a water-soluble cutting fluid composition for wire saws, and more particularly, to a water-soluble cutting fluid composition for wire saws which is excellent in dispersibility of abrasive grains and can slow down the sedimentation rate of abrasive particles in a slurry. will be.

Generally, when cutting a workpiece using cutting tools such as wire saws and band saws, cutting fluids are widely used for lubrication between the cutting tool and the workpiece, removal of frictional heat, and cleaning of cutting debris. For example, when a wafer is produced by cutting a silicon single crystal ingot as a workpiece, a nonaqueous cutting liquid is continuously supplied to the cut surface. At this time, the non-aqueous cutting liquid is a slurry in which the abrasive grain for glass polishing composed of a dispersion medium mainly composed of mineral oil or higher hydrocarbons and silicon carbide (SiC) is dispersed at a weight ratio of 1: 1. However, the dispersion medium has a bad odor and has flammability depending on the type, and thus worsens the working environment. Moreover, it is necessary to wash the workpiece cut | disconnected using the said cutting liquid using the organic solvent which can melt | dissolve and remove a cutting liquid. However, dichloroethane, which is currently used for cleaning semiconductor wafers, is designated as an ozone layer depleting substance, and the amount of use should be reduced. However, the economics and cleaning power of substitute materials are still insufficient.

On the other hand, the non-aqueous cutting liquid, it is preferable to increase the dispersibility of the abrasive grains contained in the cutting liquid in order to maintain a constant cutting performance. As a method for improving the dispersibility of abrasive grains, there are a method of adding a dispersant and a method of adding a thickener. Here, the settling speed of the abrasive grains whose dispersibility was improved by the method of adding a dispersing agent will surely become slow. However, the abrasive particles having high dispersibility are intimately contacted with each other during the deposition process and are compressed with a load exceeding the repulsive force to form a hard cake. Once the hard cake is formed, it is difficult to redistribute it to its original state. Therefore, even if the cutting liquid on which the hard cake is already formed is stirred for a long time and reused, the cutting performance is lowered as a result of the low abrasive grain concentration. In addition, there is a problem that the pipe of the cutting fluid supply system is clogged, or the wear of the tool is accelerated to crush the hard cake.

Further, the abrasive particles whose dispersibility is increased by the method of adding the thickener are guaranteed a certain effect under the assumption that the viscosity of the cutting liquid is unchanged. However, since the viscosity of the cutting fluid is changed by various factors, it is difficult to increase the dispersibility. For example, the viscosity of the cutting fluid is increased when cutting chips are mixed. In this case, the homogeneous abrasive particles cannot always be supplied to the cutting surface of the workpiece at a constant rate, and there is a problem that the cutting fluid must be replaced when the amount of cutting debris reaches 3 to 4% by weight of the cutting fluid. The cutting fluid change increases the waste volume of the cutting liquid and, in turn, increases the amount of carbon dioxide generated by incineration of the waste cutting liquid.

In addition, when moisture is mixed into the cutting fluid, the viscosity increases. In order to prevent such water incorporation, in the past, the cleaning liquid used for cleaning the wafer or the ingot adhesion base in the wire saw apparatus was limited to organic solvents, and chlorine-based organic solvents such as trichloromethane or methylene chloride and nonionics were used. System-based surfactants. Therefore, a cleaning liquid storage tank is required separately from the cutting liquid tank, which increases the area occupied by the apparatus and causes the working environment and the global environment to worsen due to the organic solvent.

It is an object of the present invention to provide an aqueous cutting fluid composition for wire saws which is environmentally friendly and can minimize the amount of viscosity due to no increase in viscosity due to cutting particles.

It is also an object of the present invention to provide a water-soluble cutting liquid composition for wire saws in which abrasive grains are stably dispersed.

It is also an object of the present invention to provide a water-soluble cutting liquid composition for wire saws, which can be easily removed from the abrasives and cutting residues of the workpiece after the cutting process, and has corrosion protection properties.

The present invention provides a water-soluble cutting fluid composition for a wire saw, comprising cyclohexanedimethanol or dimethylolpropane.

The present invention also provides a water-soluble slurry for processing comprising the water-soluble cutting liquid composition for wire saws and abrasive grains.

The water-soluble cutting liquid composition for wire saws of this invention can be used when cutting the ingot of a silicon single crystal, a silicon polycrystal, a compound semiconductor, and a ceramic. In addition, the water-soluble cutting fluid composition for a wire saw of the present invention is environmentally friendly, there is no thickening of the viscosity by the cutting particles can be used to minimize the economical. In addition, the abrasive grains are stably dispersed in the water-soluble cutting fluid composition for the wire saw of the present invention, and when slicing the workpiece with the wire saw, it is possible to exhibit excellent ability. The water-soluble cutting liquid composition for wire saws of the present invention can easily remove the cutting residues of abrasives or work products remaining after the cutting process, and has anti-corrosion properties.

Hereinafter, the present invention will be described in detail.

The water-soluble cutting fluid composition for wire saws of this invention contains cyclohexane dimethanol or dimethylol propane. The cyclohexane dimethanol or dimethylol propane acts as a thickener to improve the dispersibility of the abrasive grains.

The cyclohexane dimethanol or dimethylol propane is preferably included in an amount of 1 to 40% by weight, and more preferably in an amount of 2 to 25% by weight, based on the total weight of the composition. When included in the above-described range, when cutting ingots such as silicon single crystal, silicon polycrystal, compound semiconductor and ceramic, the dispersibility of abrasive grains is excellent. In addition, since it is water-soluble, there is no environmental problem, and it is excellent in cleaning ability for cutting residues of abrasives and work products remaining after the cutting process. In addition, even when cutting the cutting material using a water-soluble slurry for processing made by mixing the water-soluble cutting fluid composition with the abrasive grains, even if cutting chips are included, the viscosity of the water-soluble slurry for processing decreases, thereby reducing the consumption of cutting fluid. .

The water-soluble cutting fluid composition for wire saws of this invention may further contain a glycol compound. The glycol compounds serve as lubricants, friction reducing agents and corrosion inhibitors as water-soluble solvents, and act as dispersants for abrasive grains.

The glycol compound is preferably included in 50 to 99% by weight, more preferably in the 60 to 95% by weight relative to the total weight of the composition. When the above-mentioned range is satisfied, dispersibility of abrasive grains is excellent when transferring ingots such as silicon single crystal, silicon polycrystal, compound semiconductor, or ceramic. In addition, since the glycol compounds are water-soluble solvents, environmental problems do not occur, and the cleaning property of the abrasives and cutting residues of the work products remaining after the cutting process is excellent.

The glycol compound is not particularly limited as long as it is used in the art, but is not limited to ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, butylene glycol, hexylene glycol, glycerin, 1,3-propanediol , 1,4-butanediol, 1,6-hexanediol, polyethyleneglycol and polypropylene glycol is preferably one or two or more selected from the group consisting of, among which ethylene glycol, diethylene glycol and propylene glycol are more preferred. Do.

The water-soluble cutting fluid composition for wire saws of the present invention may further include water. The water may be used together with the glycol compound. The water improves the non-flammability and viscosity stability of the water-soluble cutting fluid composition for wire saws of the present invention. Industrial water, tap water, deionized water, and distilled water can be used for the water, but distilled water and deionized water without impurities are preferred, and deionized water is more preferable.

The water is preferably contained in an amount of 1 to 40% by weight, and more preferably in an amount of 2 to 25% by weight based on the total weight of the composition. If the above-mentioned range is satisfied, flammability can be prevented and the viscosity of the water-soluble cutting fluid composition for wire saws of this invention can also be suppressed.

The water-soluble cutting fluid composition for wire saws of this invention may further contain an alkanolamine compound. The alkanolamine compounds may be used together with one selected from the group consisting of glycol compounds, water and mixtures thereof. The alkanolamine compounds serve as corrosion inhibitors for corrosion protection.

The alkanolamine compounds may be contained in an amount of more than 0 and 5 wt% or less based on the total weight of the composition. If it satisfies the above range, it can perform the role of a corrosion preventing corrosion inhibitor at a minimum cost.

The alkanolamine compounds include monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, dimethylethanolamine, methyl diethanolamine, ethyl ethanolamine, diethylethanolamine, ethyl diethanolamine, isopropanolamine, isopropanoldimethylamine It is preferable that it is 1 type, or 2 or more types chosen from the group which consists of butanolamine, diglycolamine, methanol diethanolamine, and propanol diethanolamine. Among these, monoethanolamine and diethanolamine are more preferable.

The water-soluble cutting fluid composition for wire saws of the present invention can be used as a water-soluble slurry for processing, including abrasive grains. The abrasive abrasive is not particularly limited as long as it is used in the art, but is preferably one or two or more selected from the group consisting of silicon carbide, aluminum oxide, zirconium oxide, silicon dioxide, cesium dioxide and diamond. As for the average particle diameter of the said abrasive grain, 0.5-50 micrometers is preferable. The water-soluble cutting fluid and the abrasive grains are mixed in a weight ratio of 1: 0.5 to 1: 1.2, and used as a water-soluble slurry for processing.

The water-soluble slurry for processing may be performed by cutting, grinding, polishing or cutting. In the processing using the water-soluble slurry for processing, the workpiece is preferably one or two or more selected from the group consisting of single crystal silicon, polycrystalline silicon, quartz, quartz, compound semiconductor, ceramic, glass, metal oxide, cemented carbide and sintered alloy. Do.

Examples of the cutting device in which the effect of the water-soluble cutting liquid composition of the present invention and the aqueous slurry for processing using the same are particularly remarkable include a wire saw, a band saw, a multi-wire saw multiplexed these, a multi-band saw, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by the following examples.

Examples 1-4 and Comparative Examples 1-4: Preparation of Water-Soluble Cutting Fluid Composition

The cutting liquid compositions of Examples 1 to 4 and Comparative Examples 1 to 4 were prepared by mixing the compositions and contents of Table 1 with the remaining amount of deionized water. Moreover, 1 kg of abrasive grains (green silicon carbide # 1500) were mixed with respect to 1 kg of each cutting liquid composition, and a water-soluble slurry for processing was obtained by stirring at 600 rpm for 1 hour with a stirrer.

1,4-cyclohexanedimethanol
(Parts by weight) Dimethylolpropane
(Parts by weight) Alkanolamines
compound Glycol compounds Bentonite
(Parts by weight) Mineral oil
(Parts by weight) Deionized water
(Parts by weight) ingredient content
(Parts by weight) ingredient content
(Parts by weight) Example 1 5 - MEA 0.5 EG / DEG 40/55 = 95 - - - Example 2 - 6 MEA 0.3 EG / PG 35/59 = 94 - - - Example 3 5 - MEA 0.5 EG / PG 25/62 = 87 - - 8 Example 4 - 10 MEA 0.3 EG / DEG 22/58 = 80 - - 10 Comparative Example 1 - - - - EG 100 - - - Comparative Example 2 45 - - - EG - - - 55 Comparative Example 3 - - - - EG 80 5 - 15

EG: ethylene glycol DEG: diethylene glycol

PG: Propylene Glycol MEA: Monoethanolamine

Test Example: Evaluation of Characteristics of Water-Soluble Cutting Fluid Composition and Water-Soluble Slurry

Evaluation of Dispersibility of Abrasives

100 ml of the slurry prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were placed in a 100 ml measuring cylinder, and after standing, at each time of 2 hours, 4 hours, 8 hours, 12 hours, 24 hours, and 48 hours. The capacity of the abrasive grains in the lower layer was measured and the sedimentation state was observed. The lower the capacity of the lower layer, the lower the number of upper separations, and the better the dispersibility of the abrasive grains. In addition, 48 hours after standing, the measuring cylinder containing a slurry was tilted, and the redispersibility of the abrasive grains by sedimentation of the abrasive grains was observed on the following criteria.

Abrasiveness Redispersibility 4h 8h 12h 24h 48h Example 1 96 91 85 73 65 O Example 2 96 92 87 76 69 O Example 3 95 90 85 73 63 O Example 4 95 91 86 75 67 O Comparative Example 1 91 83 73 54 52 △ Comparative Example 2 92 85 77 62 53 △ Comparative Example 3 95 90 86 74 64 X

O: The entire abrasive layer flows smoothly

△: The entire abrasive layer flows slowly

X: The abrasive layer hardly flows (hardcake)

<Viscosity Evaluation>

The viscosity of the slurry with respect to the cutting liquid of Examples 1-4 and Comparative Examples 1-4 was measured. Subsequently, 5 weight% and 10 weight% of silicone powder (# 325) were added to each slurry, the mixture was stirred, and the slurry viscosity was measured. Moreover, the viscosity change rate before and after mixing of silicon powder = (viscosity after silicon powder mixing) / (viscosity before silicon powder mixing) was calculated | required. The closer the viscosity change rate is to 1, the smaller the change in viscosity at the time of cutting of ingots and the like, indicating that stable workability is obtained.

Slurry Viscosity According to Silicon Powder Input (mPas) Viscosity change rate 0% by weight 5 wt% 10% by weight 5 wt% 10% by weight Example 1 135 175 210 1.30 1.56 Example 2 142 175 210 1.23 1.48 Example 3 145 180 220 1.24 1.52 Example 4 135 170 205 1.26 1.52 Comparative Example 1 120 180 245 1.50 2.04 Comparative Example 2 140 190 260 1.36 1.86 Comparative Example 3 145 195 265 1.34 1.83

Referring to Tables 2 and 3, the use of the water-soluble cutting liquid composition of each example is superior in dispersibility compared with the use of the cutting liquid of the comparative example, and the change in viscosity even when debris of the cutting material is added during cutting Small amount was confirmed.

Corrosion Performance Evaluation

In order to confirm the corrosion performance with the cutting liquid of each of the above Examples and Comparative Examples, a polarization test was carried out. The test equipment used was Solartron's Potentiostat / Galvanostat model 263A. Graphite was used as the counter electrode, saturated calomel electrode (SCE) as the reference electrode, and stainless steel specimen as the working electrode. It was.

After sufficiently saturating the air, the Tafel curve (copotential polarization curve) was measured, and the potential scanning region was measured at a potential speed of 0.166 mV / s up to 1.5 VSCE at the natural potential. The specimen used at this time was made of gray cast iron (FC20) as a specimen (1.5 cm x 1.5 cm).

Corrosion Current (uA / cm ² ) Corrosion degree (um / yr) DIW 2.56 29.66 Example 1 1.38E-02 0.16 Example 2 2.14E-02 0.25 Example 3 3.74E-02 0.43 Example 4 4.87E-02 0.56 Comparative Example 1 1.21E-01 1.85 Comparative Example 2 6.88E-01 7.98 Comparative Example 3 3.49E-01 4.30

Referring to Table 4, it can be seen that when the water-soluble cutting liquid composition of each example is used, it exhibits excellent corrosion protection properties compared to the cutting liquid of the comparative example.

Claims (10)

A water-soluble cutting fluid composition for a wire saw, comprising cyclohexanedimethanol or dimethylolpropane. The method according to claim 1, In terms of the total weight of the composition, 1 to 40% by weight of the cyclohexanedimethanol or dimethylolpropane, the water-soluble cutting fluid composition for a wire saw. The method according to claim 1, A water-soluble cutting fluid composition for wire saws, comprising a glycol compound. The method of claim 3, In terms of the total weight of the composition, The glycol compound is a water-soluble cutting fluid composition for a wire saw, characterized in that it comprises 50 to 99% by weight. The method according to claim 1 or 3, Cutting fluid composition for a wire saw, characterized in that it further comprises water. The method according to claim 5, In terms of the total weight of the composition, The cutting fluid composition for a wire saw, characterized in that the water comprises 1 to 40% by weight. The method according to claim 1 or 3 or 5, An aqueous cutting liquid composition for wire saws, further comprising an alkanolamine compound. The method of claim 7, In terms of the total weight of the composition, The alkanolamine compound is a cutting fluid composition for a wire saw, characterized in that it comprises more than 0 weight 5 wt. A water-soluble cutting fluid composition for a wire saw according to claim 1, and an abrasive grain. The method according to claim 9, The water-soluble slurry for processing is a water-soluble slurry for processing, characterized in that for performing cutting, grinding, polishing or cutting.