Cutting oil composition

Abstract

The invention relates to a cutting oil composition used in a cutting process of a wire-saw (wire-saw). The cutting oil composition is composed of 50 to 95 wt% of a base oil represented by Chemical Formula 1, Chemical Formula 2 or Chemical Formula 3, 0.1 to 5 wt% of a chelating agent, 0.1 to 10 wt% of a thickening agent, 0.1 to 5 wt% of a dispersant, 1 to 20 wt% of an oiliness enhancer, and 1 to 10 wt% of a nonionic surfactant, and has the effects that: the content of the base oil is less than or equal to 50 wt%; all characteristics such as residual metal impurity removal capacity, cleaning capacity, viscosity, surface tension, corrosivity, dispersity, lubricity, wafer uniformity and abrasion resistance are comprehensively excellent, and particularly, the cleaning capacity and the metal ion impurity removal capacity are remarkably excellent.

Description

Technical Field

[0001] The present invention relates to a cutting oil composition used in an on-line wire-saw cutting process. In particular, the present invention relates to a wire-saw cutting fluid composition comprising a metal removal chelating agent composed of a nitrogen-containing carboxylic acid or carboxylate compound, a highly hydrogenated hydrocarbon fraction base oil, a thickener, a dispersant, an oiliness enhancer, and a nonionic surfactant. Background Art

[0002] Wire-saw cutting is the main method for cutting ingots to manufacture thin wafers used in the integrated circuit and photovoltaic cell industries.

[0003] In addition, this method is also commonly used to fabricate wafers from substrates of other materials, such as sapphire, silicon carbide, or ceramic substrates.

[0004] Typically, a wire-saw has a web or wireweb of fine metal wires, where each wire has a diameter of about 0.15 mm and is arranged parallel to each other at a distance of 0.1 to 1.0 mm through a series of spools, pulleys, and wire guides. Cutting is achieved by bringing a workpiece such as a substrate into contact with the moving wire to which the cutting oil composition has been applied.

[0005] In a typical wire-saw cutting process, a composition prepared by mixing abrasive particles composed of hard substances such as silicon carbide particles in a cutting oil composition including a mineral oil or synthetic oil, a thickener, a dispersant, etc. in a weight ratio of about 1:1 is used.

[0006] The cutting oil composition is a liquid that provides lubrication and cooling and holds the abrasive on the wire, enabling the abrasive to contact the workpiece being cut.

[0007] In order for the cutting oil to exhibit optimal performance, an appropriate balance between lubricity and viscosity is required. When the lubricity is too high, the fine abrasive particles cannot adhere to the workpiece being processed and instead slide, reducing the cutting ability. When the lubricity is low, each fine abrasive particle cannot exert its full cutting ability. Recently, companies performing wire-saw processes are reusing the oil that has been used once. Due to this reused cutting oil and abrasive particles, in the wire-saw process, the copper alloy plated on the wire is peeled off, and copper ions penetrate into the wafer surface, increasing the metal contamination of the wafer surface.

[0008] As the cutting oil composition, it can be a hydrophobic substance such as a mineral oil, kerosene, polyethylene glycol, polypropylene glycol, or other polyalkylene glycols, and hydrophilic substances can also be used in the wire-saw cutting process.

[0009] The existing cutting oil compositions have the following problems: In the wire saw process, the copper alloy plated on the wire is stripped, and copper ions remain or penetrate into the surface of the wafer, thereby increasing contamination, or the dispersibility of the abrasive particles decreases, or the suspension persistence of the abrasive particles decreases, or the lubricity is too small or too large, or the wafer cleaning time after the wire saw process is too long, or defects with a large degree of wafer warping are often induced after the wire saw process.

[0010] The cutting oil is pre-mixed with the abrasive particles in a mixer in a fuel tank attached to the cutting equipment and then used. In order to prevent the phenomenon of the cutting oil and the abrasive particles from separating again, it is necessary to use a small mixer for re-dispersion operations at any time. The separated abrasive particles will aggregate and combine with each other, resulting in clogging of the cutting oil delivery pipe, problems with circulation, and insufficient suspension persistence, lubricity, and dispersibility of the cutting oil, leading to problems such as wire wear, uneven wafer cutting, and shortened life of the slurry particles, thus increasing the manufacturing cost and also reducing the cleaning power in subsequent processes. Due to the repeated use of the cutting oil, in the wire saw process, the copper alloy plated on the wire is stripped, and these metal impurities penetrate into the silicon of the silicon wafer, thereby increasing the impurity density on the surface of the silicon wafer.

[0011] For this reason, in order to prevent metal residues from mixing into the process or penetrating into the wafer surface during the cutting process using the cutting oil, various attempts have been made to improve the chelating agents added to the cutting oil. For example, EDTA (ethylenediaminetetraacetic acid) or DTPA (diethylenetriaminepentaacetic acid) do not dissolve well or have insufficient effects in mineral oils or synthetic oils used as base oils.

[0012] That is, for the existing cutting oil compositions, when comprehensively evaluating the dispersibility, cleaning power, degree of wafer warping after the wire saw process, and concentration of metal ion impurities on the wafer surface after the wire saw process, if one or more of these characteristics are poor, it is equivalent to a non-conforming cutting oil composition.

[0013] In order to improve these problems, the prior patent (Registration No.: 10-2062341) invented and patented by the present inventors has various properties such as good viscosity, abrasive particle dispersibility, cleanliness, wafer uniformity, and wear resistance, and is therefore effectively used in the cutting process. However, the actual situation is that there are still metal ion impurities, especially copper (Cu), nickel (Ni), manganese (Mn), chromium (Cr), iron (Fe), etc., remaining or penetrating into the wafer surface after the cutting process using the cutting oil composition of the prior patent.

[0014] (Prior Art Documents)

[0015] (Patent Document 1) Korean Registered Patent Gazette No. 10-2062341

[0016] (Patent Document 2) Korean Patent Publication No. 10-2009-48518

[0017] (Patent Document 3) Korean Patent Publication No. 10-2009-65847

[0018] (Patent Document 4) Korean Patent Publication No. 10-2011-39725 Summary of the Invention

[0019] Technical Problem to be Solved

[0020] In order to solve the above problems, the present invention provides a cutting oil composition which has no more than one poor characteristic when evaluating all characteristics such as the removal force of residual metal impurities, detergency, viscosity, surface tension, corrosiveness, dispersibility, lubricity, wafer uniformity, and abrasion resistance. Compared with the existing cutting oil compositions, all characteristics are comprehensively excellent, and in particular, the detergency and the removal force of metal ion impurities are significantly excellent.

[0021] Solution to the Problem

[0022] In order to achieve the above object of the present invention, a cutting oil composition is provided as a means for solving the problem. The cutting oil composition contains a base oil, a chelating agent, a thickening agent, a dispersant, an oiliness enhancer, and a nonionic surfactant of the following Components A to F. Each component will be described below, and the composition as a mixture thereof will be described.

[0023] 1. Component A

[0024] Component A is one or more highly hydrogenated base oils represented by the following Chemical Formula 1, Chemical Formula 2, or Chemical Formula 3.

[0025] [Chemical Formula 1]

[0026] R1-(CnH2n-4)a-R2

[0027] [Chemical Formula 2]

[0028] R3-(CnH2n-2)b-R4

[0029] [Chemical Formula 3]

[0030] R5-(CnH2n)c-R6

[0031] In the above Chemical Formulas 1 to 3, n is 5 or 6, a is 3 to 7, b is 40 to 50, c is 45 to 55, and R1, R2, R3, R4, R5, and R6 are each H or OH.

[0032] Among them, in the prior patent Korean Patent Registration Patent Gazette No. 10-2062341, for the base oil of Component A in Chemical Formulas 1 to 3 above, a is 7 to 20, b is 39 to 52, and c is 39 to 41. However, in contrast, in the present invention, as a result of more in-depth research, it is shown that for the base oil of Component A in Chemical Formulas 1 to 3 above, preferably a is 3 to 7, b is 40 to 50, and c is 45 to 55. Further, it is shown that, particularly, most preferably a is 5, b is 45, and c is 50.

[0033] In addition, the base oil of Component A is preferably mixed in similar amounts from Chemical Formulas 1 to 3 above. In particular, most preferably, it is mixed in the same amounts from Chemical Formulas 1 to 3.

[0034] Among them, based on the whole composition, the content of the base oil of Component A is preferably 50 to 95% by weight.

[0035] 2. Component B

[0036] Component B is a chelating agent for removing metals. The chelating agent is a nitrogen-containing carboxylic acid or carboxylate compound, which is a substance selected from the group consisting of γ-aminobutyric acid, nitrilotriacetic acid, diaminosuccinic acid, diethyl iminocarbonate, β-aminobutyric acid, succinamic acid, alanine, iminodiacetic acid, ethyl 3-amino-3-ureidobutyrate, 2-aminosuccinic acid, 2-aminoglutaric acid, 2-amino-3-carbamoylpropionic acid, 2-amino-4-carbamoylbutyric acid, 2-amino-5-formamidinovaleric acid, 2,4-diaminoglutaric acid, 2,6-diaminohexanoic acid, 3-aminovaleric acid, and N-hydroxymethylformamidoacetic acid, glutaric acid, nicotinic acid, maleic acid, malonic acid, malic acid, valeric acid, butyric acid, succinic acid, citric acid, acetic acid, acrylic acid, oxalic acid, lactic acid, formic acid, propionic acid, phthalic acid, and their salts, or a mixture thereof.

[0037] Among them, based on the whole composition, the content of the chelating agent of Component B is preferably 0.1 to 5% by weight.

[0038] 3. Component C

[0039] Component C is a thickening agent, which is a substance selected from the group consisting of fined chalk powder, fined clay powder, sorbitan monooleate, fine organic composite substances containing α-olefins, and bentonite, or a mixture thereof, and most preferably bentonite.

[0040] Among them, based on the whole composition, the content of the thickening agent of Component C is preferably 0.1 to 10% by weight.

[0041] 4. Component D

[0042] Component D is a dispersant, which is a substance selected from the group consisting of Fe2O3, Na2O, Al2O3, and Si2O, or a mixture thereof, more preferably Fe2O3, Na2O, or a mixture thereof.

[0043] Among them, based on the whole composition, the content of the dispersant of Component D is preferably 0.1 to 6% by weight.

[0044] 5. Component E

[0045] Component E is an oil-based strengthening agent, which is one or more selected from the group consisting of vegetable and animal fatty acid oils represented by the following Chemical Formula 4 and alkyl oleate represented by Chemical Formula 5. Based on the total weight of the composition, the content of Component E is preferably 1 to 20% by weight.

[0046] [Chemical Formula 4]

[0047] R7-COO-R8

[0048] In the above chemical formula, R7 is hydrogen or an alkyl group, R8 is a saturated fatty acid, unsaturated fatty acid, vegetable or animal fatty acid ester of C11-C22, and the above chemical formula is an ester compound derived from a tri- to pentavalent alcohol and a monobasic fatty acid.

[0049] [Chemical Formula 5]

[0050] R9-C(CH3)2(OCOR10)

[0051] In the above chemical formula, R9 is methyl, ethyl, propyl or butyl, R10 is an alkyl group of C11-C22, and the above chemical formula is an ester compound derived from a tri- to pentavalent alcohol and a monobasic fatty acid.

[0052] 6. Component F

[0053] Component F is a non-ionic surfactant, which is one or more selected from the group consisting of the following Chemical Formula 6. Based on the total weight of the composition, the content of Component F can be 1 to 10% by weight.

[0054] [Chemical Formula 6]

[0055] R11-(AO)n-R12

[0056] In the above chemical formula, R11 and R12 are each independently a hydrogen group (-H), a hydroxyl group (-OH), a straight-chain or branched-chain alkyl group having 1 to 20 carbon atoms, or a straight-chain or branched-chain alkenyl group having 1 to 20 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, and n is a natural number from 1 to 25.

[0057] On the other hand, the above cutting oil composition is characterized by being used for dispersing abrasives. As the above abrasive, silicon carbide can be used, and silica powder and coke powder can be obtained in an electric furnace by a thermal carbonization reduction method, and it is green or dark gray depending on the temperature. Generally, SiC is prepared with an extremely high hardness of Knoop hardness of 2700 or more and Mohs hardness of 9.5 or more, so the grinding power is very excellent, and it is mainly used as an abrasive for silicon substrates for semiconductors and solar cells.

[0058] As a method for dispersing these abrasive (Green-SiC) particles in oil, in addition to dispersing treatment by a usual stirrer, a homogenizer, an ultrasonic disperser, a ball mill, etc. can also be used. In order to disperse particles with a size of less than micrometers, dispersing devices such as a ball mill, a vibration ball mill, a planetary ball mill, a medium stirring type mill, etc. are preferably used.

[0059] Effects of the Invention

[0060] The effect of the present invention is to provide a cutting oil composition, in which one or more of all characteristics such as the residual metal impurity removal power, cleaning power, viscosity, surface tension, corrosiveness, dispersibility, lubricity, wafer flatness, and abrasion resistance are not inferior to those of the existing cutting oil composition, and all characteristics are comprehensively excellent, especially the cleaning power and the metal ion impurity removal power are significantly excellent. Detailed Description of the Invention

[0061] Best Mode for Carrying Out the Invention

[0062] Hereinafter, embodiments of the present invention will be described in detail. However, these are only presented as examples, and the present invention is not limited by these examples, and the present invention is only defined by the scope of the following claims.

[0063] Hereinafter, the components of the cutting oil composition applicable to the present invention will be described in detail.

[0064] 1. Component A

[0065] Component A is the base oil contained in the composition. As the base oil of Component A, for example, paraffin or naphthenic low-viscosity base oil as a pure lubricating oil, etc. are included. The paraffinic and naphthenic base oils of Component A are the base substances for dispersing and dissolving the following additives. In order to prevent the separation phenomenon of the additives according to the temperature change, a base oil with a low pour point is preferably used, and in order to ensure the safety of the environment and the workplace, a high-purity, highly refined base oil is preferably used. Based on the whole composition, the content of this Component A is 50 to 95% by weight. A base oil containing both naphthenic base oil and paraffinic base oil is preferably contained.

[0066] [Chemical Formula 1]

[0067] R1-(CnH2n-4)a-R2

[0068] [Chemical formula 2]

[0069] R3-(CnH2n-2)b-R4

[0070] [Chemical formula 3]

[0071] R5-(CnH2n)c-R6

[0072] In the above Chemical formula 1 to Chemical formula 3, n is 5 or 6, a is 3 to 7, b is 40 to 50, c is 45 to 55, and R1, R2, R3, R4, R5 and R6 are H or OH respectively.

[0073] 2. Component B

[0074] Component B of the composition is a chelating agent for removing metals composed of a nitrogen-containing carboxylic acid or carboxylate compound. As specific examples of Component B, the nitrogen-containing carboxylic acids are γ-aminobutyric acid, nitrilotriacetic acid, diaminosuccinic acid, diethyl iminocarbonate, β-aminobutyric acid, succinamic acid, alanine, iminodiacetic acid, ethyl 3-amino-3-ureidobutyrate, 2-aminosuccinic acid, 2-aminoglutaric acid, 2-amino-3-carbamoylpropionic acid, 2-amino-4-carbamoylbutyric acid, 2-amino-5-formimidoylvaleric acid, 2,4-diaminoglutaric acid, 2,6-diaminohexanoic acid, 3-aminovaleric acid and N-hydroxyformimidoyl acetic acid. As the carboxylic acids, glutaric acid, nicotinic acid, maleic acid, malonic acid, malic acid, valeric acid, butyric acid, succinic acid, citric acid, acetic acid, acrylic acid, oxalic acid, lactic acid, formic acid, propionic acid, phthalic acid and their salts can be used. Based on the total weight of the cutting oil composition, Component B can be used in the range of 0.1 to 5% by weight, preferably 0.3 to 3% by weight.

[0075] The above chelating agent for removing metals has a coordination number of 2 to 6, and thus can effectively form a complex with metals having the outermost electrons in the 4s and 3d orbitals. On the other hand, the metals having the outermost electrons in the 4s and 3d orbitals as described above exist in the form of atoms and ions with relatively small sizes, and thus are not easily complexed with chelates having a coordination number of 7 or more.

[0076] For chelating agents having a coordination number of 7 or more, they are easily complexed with metals having the outermost electrons in the 5f orbital. Therefore, for metals with relatively small sizes in the fourth and lower periods of the periodic table such as copper (Cu), nickel (Ni), manganese (Mn), chromium (Cr), iron (Fe), etc., the ability to form complexes will decrease.

[0077] The chelating agent having a coordination number of 2 to 6 added to the cutting oil composition of the present invention has excellent ability to form complexes with metals such as magnesium (Mg), aluminum (Al), potassium (K), calcium (Ca), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), lead (Pb), etc., particularly for fourth-period metals such as copper (Cu), nickel (Ni), manganese (Mn), chromium (Cr), iron (Fe), etc., and thus has excellent ability to prevent metal ions generated in the cutting process from remaining or infiltrating into the wafer.

[0078] 3. Component C

[0079] Component C of the composition is a composite dispersion powder selected from the group consisting of a composite dispersion powder containing α-olefin, fined chalk powder, fined clay powder, and sorbitan monooleate, or a composite dispersion powder selected from the group consisting of organoclay and organobentonite. This component C, as a fine organic composite substance, is used as a thickening agent. Component C keeps the inorganic particles contained in the slurry having appropriate adhesiveness, so that they are uniformly dispersed on the cutting tool (wire). The bentonite, which is a component contained in the composite dispersion powder used in this component C, is represented as NaSi(AlMg)O(OH), for example. Based on the total weight of the composition, the content of component C is 0.1 to 10% by weight, preferably containing 1 to 5% by weight. When the content of component C is less than 0.1% by weight, the slurry cannot maintain appropriate adhesiveness, and when it exceeds 10% by weight, the adhesiveness is too strong and inappropriate.

[0080] 4. Component D

[0081] Component D of the composition is a dispersant containing one or more substances selected from the group consisting of Fe2O3, Na2O, Al2O3, and Si2O. The powder used as component D, as a dispersant, makes it easy for the slurry powder to be dispersed in the cutting oil. Based on the whole composition, the content of component D is 0.1 to 5% by weight, preferably containing 0.5 to 3% by weight. When the content of component D is less than 0.1% by weight, the slurry powder is not easily dissolved and dispersed in the cutting oil, and when the content of component D exceeds 6% by weight, the slurry powder will be overly dissolved and dispersed, so that the cutting operation cannot be carried out smoothly.

[0082] 5. Component E

[0083] Component E of the composition is one or more oiliness enhancers selected from the group consisting of vegetable and animal fatty acid oils or alkyl oleates. Among them, the oiliness enhancer is a substance represented by the following Chemical Formula 4 or Chemical Formula 5, or a mixture thereof.

[0084] [Chemical Formula 4]

[0085] R7-COO-R8

[0086] In the above chemical formula, R7 is hydrogen or an alkyl group, R8 is a saturated fatty acid, unsaturated fatty acid, vegetable or animal fatty acid ester having 11 to 22 carbon atoms, and the above chemical formula is an ester compound derived from a tri- to pentavalent alcohol and a monobasic fatty acid.

[0087] [Chemical formula 5]

[0088] R9-C(CH3)2(OCOR10)

[0089] In the above chemical formula, R9 is methyl, ethyl, propyl or butyl, R10 is an alkyl group having 11 to 22 carbon atoms, and the above chemical formula is an ester compound derived from a tri- to pentavalent alcohol and a monobasic fatty acid.

[0090] As the oiliness enhancer of component E, synthetic and natural fatty oils are used, which impart appropriate lubricity to the cutting process (wire sawing). In order to reduce the increase in viscosity and oil separation phenomenon caused by the solidification phenomenon at low temperatures, higher synthetic esters or higher fatty oils are used. Based on the whole composition, the content of this oiliness enhancer is 1 to 20% by weight, and preferably contains 5 to 10% by weight. When the content of the oiliness enhancer is less than 1% by weight, the oil separation phenomenon will occur, resulting in problems with storage stability. When the content exceeds 20% by weight, the viscosity decreases and the lubricity increases, so that each fine abrasive particle cannot exert sufficient cutting ability.

[0091] 6. Component F

[0092] Component F of the composition is a nonionic surfactant. In the present invention, it is an auxiliary substance that functions as a cleaning and lubricating functional additive. It is a substance represented by the following chemical formula 6. Specifically, polyethylene glycol fatty acid diester (HLB: 10.4), sorbitan fatty acid ester (HLB: 9.6), polyethylene glycol fatty acid diester (HLB: 8.4), ethoxylated propoxylated alcohols (HLB: 7.3), polyoxyethylene lauryl ether (HLB: 6.2), etc. can be cited. Based on the whole composition, the content of the nonionic surfactant as component F is 1 to 10% by weight.

[0093] [Chemical formula 6]

[0094] R11-(AO)n-R12

[0095] In the above chemical formula, R11 and R12 are each independently a hydrogen group (-H), a hydroxyl group (-OH), a linear or branched alkyl group having 1 to 20 carbon atoms, or a linear or branched alkenyl group having 1 to 20 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, and n is a natural number from 1 to 25.

[0096] Specific Modes for Carrying Out the Invention

[0097] The specific composition and efficacy of the present invention will be described in more detail by the following Examples and Experimental Examples.

[0098] [Examples 1 to 28 and Comparative Examples 1 to 15]

[0099] In each experimental beaker equipped with a homo-mixer, the cutting oil compositions of the Examples and Comparative Examples were added according to the composition ratios described in Table 1, and then the top of the beaker was sealed, and then stirred at a speed of 3000 rpm for 90 minutes at room temperature to prepare the compositions.

[0100] The HLB (Hydrophile-Lipophile Balance) value of the nonionic surfactant is a value measured by the Griffin method. The HLB value is a value indicating the degree of affinity of the surfactant for water or oil. The range of the HLB value is divided into 0 to 20. The closer the HLB value is to 0, the stronger the hydrophobic (lipophilic) property of the nonionic surfactant, and the closer the HLB value is to 20, the stronger the hydrophilic property of the nonionic surfactant.

[0101] [Table 1]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107] [Experimental Examples 1 to 28 and Comparative Experimental Examples 1 to 15]

[0108] For the compositions prepared from Examples 1 to 28 and Comparative Examples 1 to 15 above, the results of each test item were measured by the following methods (1) to (7).

[0109] (1) Viscosity

[0110] Viscosity measurement was carried out using a DV-II+Pro model from BROOKFIELD, with spindles No. 61 and No. 62 at a spindle speed of 60 rpm.

[0111] At this time, those with viscosities in the range of 60 to 120 mPa·s at 25°C are suitable as cutting oil compositions.

[0112] (2) Surface tension

[0113] The cutting oil composition was measured using a surface tension meter (model: Tensiometer K100, manufacturer: KRUSS).

[0114] (3) Dispersion of abrasive particles

[0115] The dispersion was evaluated by filling a graduated cylinder with a slurry obtained by mixing cutting oil and silicon carbide (SiC) powder at a weight ratio of 1:1, and measuring the amount of water in the upper layer after standing at room temperature for 7 days.

[0116] At this time, those with no upper layer water or a small amount of upper layer water are suitable as cutting oil compositions.

[0117] (4) Cleaning power

[0118] A contaminated sample was prepared by coating a mixture of cutting oil and cutting residues (abrasives, wafer fragments) generated after cutting the wafer on the wafer and drying it at 85°C for 8 hours.

[0119] Two contaminated samples were joined and fixed at an interval of 0.2 mm, then immersed in a cleaning solution (model: YKC-B620, manufacturer: Rongchang Chemical), cleaned at 40°C for 10 minutes, and then rinsed with water 3 times. The degree of residual pollution sources on the wafer surface is as follows.

[0120] <Evaluation criteria>

[0121] ◎: Contaminants remain within 5% of the total area

[0122] ○: Contaminants remain within 5 - 15% of the total area

[0123] △: Contaminants remain within 15 - 25% of the total area

[0124] X: Contaminants remain more than 25% of the total area

[0125] (5) Wafer flatness

[0126] For the measurement of the flatness degree of the wafer after sawing, it is completed by evaluating the warpage degree of each wafer using equipment after cleaning. At this time, when the warpage degree of the wafer after sawing is evaluated to be 10 μm or less, it indicates that the cutting oil composition is excellent.

[0127] (6) Metal ion removal ability

[0128] To determine the degree to which metal impurities generated in the cutting process are removed or controlled by the cutting oil, Cu / Ni standard solutions are used to contaminate the surface of silicon wafers with Cu / Ni impurities at a concentration of 1.0E12 atoms / cm 2 respectively by spin coating, and then the following method is used for the experiment, and the amount of metal impurities infiltrated into the wafer surface before and after immersion in the cutting oil is calculated.

[0129] At this time, a cutting oil composition with a small remaining amount of metal impurities is suitable.

[0130] 1) Immerse the silicon wafers contaminated with the Cu and Ni standard solutions in each cutting oil composition containing a chelating agent for metal removal prepared in the examples and comparative examples at room temperature for 5 minutes each.

[0131] 2) Wash the immersed wafers with refined kerosene and isopropyl alcohol, then dry them with nitrogen, and then store them in a nitrogen box.

[0132] 3) Then, spread a solution mixed with 1 wt% hydrofluoric acid and 1 wt% hydrogen peroxide onto the wafer surface, spray it on the wafer surface for 5 minutes, and then etch the wafer surface for 5 minutes.

[0133] 4) Then, use a polyethylene pipette to recover all the solution on the above wafers, and then analyze it using an inductively coupled plasma spectrometry (ICP-MS, manufacturer: Agilent, model: 7700).

[0134] (7) Abrasion resistance

[0135] Under the conditions of 1200 ± 50 rpm, a cutting oil temperature of 75 ± 5 °C, and a load of 40 ± 0.2 kg, the wear resistance of the cutting oil composition is tested according to the ASTM D2266 four-ball wear test method for 30 minutes. After the test, clean the balls, and measure the wear marks and the wear mark diameters shown as results for comparison.

[0136] At this time, a cutting oil composition without wear marks or with small wear marks is suitable.

[0137]

Table 2

[0138]

[0139]

[0140]

[0141] As shown in Table 2 above, it can be confirmed that, compared with Comparative Examples 1 to 15, the wafer cutting oil compositions of Examples 1 to 28 according to the present invention are excellent in detergency after the cutting process, have a low residual metal ion impurity concentration, and thus have excellent ability to remove metal ion impurities. It can also be confirmed that the viscosity, surface tension, dispersibility, wafer uniformity, and abrasion resistance are also excellent.

Claims

1. A cutting oil composition, characterized in that, the cutting oil composition is composed of a base oil represented by the following Chemical Formula 1, Chemical Formula 2 or Chemical Formula 3, a chelating agent, a thickening agent, a dispersant, an oiliness enhancer, and a nonionic surfactant, [Chemical Formula 1] R1-(CnH2n-4)a-R2 [Chemical Formula 2] R3-(CnH2n-2)b-R4 [Chemical Formula 3] R5-(CnH2n)c-R6 In the above Chemical Formula 1 to Chemical Formula 3, n is 5 or 6, a is 3 to 7, b is 40 to 50, c is 45 to 55, and R1, R2, R3, R4, R5 and R6 are H or OH respectively.

2. The cutting oil composition according to claim 1, characterized in that, the cutting oil composition is composed of 50 to 95% by weight of a base oil, 0.1 to 5% by weight of a chelating agent, 0.1 to 10% by weight of a thickening agent, 0.1 to 5% by weight of a dispersant, 1 to 20% by weight of an oiliness enhancer, and 1 to 10% by weight of a nonionic surfactant.

3. The cutting oil composition according to claim 2, characterized in that, in the above Chemical Formula 1 to Chemical Formula 3, a is 5, b is 45, and c is 50.

4. The cutting oil composition according to claim 3, characterized in that, the chelating agent is a substance selected from the group consisting of γ-aminobutyric acid, nitrilotriacetic acid, diaminosuccinic acid, diethyl iminocarbonate, β-aminobutyric acid, succinamic acid, alanine, iminodiacetic acid, ethyl 3-amino-3-ureidobutyrate, 2-aminosuccinic acid, 2-aminoglutaric acid, 2-amino-3-carbamoylpropionic acid, 2-amino-4-carbamoylbutyric acid, 2-amino-5-formimidoylvaleric acid, 2,4-diaminoglutaric acid, 2,6-diaminohexanoic acid, 3-aminovaleric acid, and N-hydroxyformimidoyl acetic acid, glutaric acid, nicotinic acid, maleic acid, malonic acid, malic acid, valeric acid, butyric acid, succinic acid, citric acid, acetic acid, acrylic acid, oxalic acid, lactic acid, formic acid, propionic acid, phthalic acid, and their salts, or a mixture thereof.

5. The cutting oil composition according to claim 3, characterized in that, the thickening agent is a substance selected from the group consisting of micronized chalk, micronized clay, sorbitan monooleate, a fine organic composite substance containing α-olefin, and micronized bentonite, or a mixture thereof.

6. The cutting oil composition according to claim 3, characterized in that, the dispersant is a substance selected from the group consisting of Fe2O3, Na2O, Al2O3, and Si2O, or a mixture thereof.

7. The cutting oil composition according to claim 6, characterized in that, the dispersant is Fe2O3, Na2O, or a mixture thereof.

8. The cutting oil composition according to claim 3, characterized in that, the oiliness enhancer is a substance represented by the following Chemical Formula 4 or Chemical Formula 5, or a mixture thereof, [Chemical Formula 4] R7-COO-R8 In the above chemical formula, R7 is hydrogen or an alkyl group, R8 is a saturated fatty acid, unsaturated fatty acid, vegetable or animal fatty acid ester having 11 to 22 carbon atoms, and the above chemical formula is an ester compound derived from a tri- to pentavalent alcohol and a monobasic fatty acid. [Chemical Formula 5] R9-C(CH3)2(OCOR10) In the above chemical formula, R9 is a methyl, ethyl, propyl or butyl group, R10 is an alkyl group having 11 to 22 carbon atoms, and the above chemical formula is an ester compound derived from a tri- to pentavalent alcohol and a monobasic fatty acid.

9. The cutting oil composition according to claim 3, wherein the nonionic surfactant is a substance represented by the following Chemical Formula 6 [Chemical Formula 6] R11-(AO)n-R12 In the above Chemical Formula 6, R11 and R12 are each independently a hydrogen group (-H), a hydroxyl group (-OH), a straight-chain or branched-chain alkyl group having 1 to 20 carbon atoms, or a straight-chain or branched-chain alkenyl group having 1 to 20 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, and n is a natural number from 1 to 25.

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