A large silicon wafer cutting fluid, its preparation method and use

Abstract

The application discloses a large silicon wafer cutting fluid, a preparation method and application thereof; the cutting fluid comprises the following components in mass parts: 20-40 parts of a wetting agent, 1-10 parts of a lubricant, 0.1-2 parts of a preservative, 20-40 parts of deionized water and 5-20 parts of an organic solvent; wherein the lubricant is used for forming a protective film on the surface of the silicon wafer, and the preservative is used for forming an adsorption film on the surface of the diamond wire. The cutting fluid realizes the cutting of the fine-diameter diamond wire, the existence of the protective film reduces the problems of dirt and wire marks caused by the direct contact between the silicon wafer and the diamond wire, and the breakage of the diamond wire is avoided; the existence of the adsorption film can also slow down the corrosion speed of the diamond wire material, and further reduce the breakage rate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor cutting, and particularly relates to a large silicon wafer cutting liquid, a preparation method and application thereof. BACKGROUND

[0002] The silicon wafer belongs to a hard material, and a large amount of heat and abrasion is generated in the process of diamond wire cutting. In order to adapt to the change of the size of the silicon wafer and improve the cutting efficiency, the diamond wire is developed to a thin wire diameter, which puts forward higher requirements for the performance of the cutting liquid. In particular, the cutting liquid used for the thin wire diameter diamond wire has problems such as dirt, wire marks, wire breakage rate and the like, which affect the preparation of large-size and thin silicon wafers. SUMMARY

[0003] The application provides a large silicon wafer cutting liquid, a preparation method and application thereof, solves the problems such as dirt, wire marks, wire breakage rate and the like of the cutting liquid used for the thin wire diameter diamond wire, and provides good cutting force and improves the cutting efficiency.

[0004] The application provides a large silicon wafer cutting liquid, which is applied to cutting of a silicon wafer by diamond wire. The cutting liquid comprises the following components in mass parts: 20-40 parts of a wetting agent, 1-10 parts of a lubricant, 0.1-2 parts of a preservative, 20-40 parts of deionized water and 5-20 parts of an organic solvent.

[0005] The lubricant is used to form a protective film on the surface of the silicon wafer, and the preservative is used to form an adsorption film on the surface of the diamond wire.

[0006] In some embodiments, at least one of the lubricant and the preservative has an amide group.

[0007] In some embodiments, the lubricant is selected from at least one of stearamidopropyl dimethylamine, oleic acid amide, erucic acid amide and stearamide; and / or

[0008] The preservative is selected from a fatty acyl amino acid surfactant.

[0009] In some embodiments, the carbon chain length of the fatty in the fatty acyl amino acid surfactant is C 10 ~ C 20 ; and / or

[0010] The amino acid in the fatty acyl amino acid surfactant is selected from at least one of glutamic acid, glycine, alanine and sarcosine.

[0011] In some embodiments, the fatty acyl amino acid surfactant is selected from at least one of sodium lauroyl glutamate, sodium lauroyl glycinate, sodium lauroyl alaninate, sodium lauroyl sarcosinate, sodium cocoyl glycinate, sodium cocoyl glutamate, and sodium stearoyl glutamate.

[0012] In some embodiments, the wetting agent is a fatty alcohol polyoxyethylene polyoxypropylene ether, with a chemical formula of RO(CH2CH2O) m (C3H6O) n H, wherein R is selected from C3-C8 hydrocarbon groups; m represents the addition number of ethylene oxide groups, selected from an integer from 2 to 8; and n represents the addition number of propylene oxide groups, selected from an integer from 4 to 10.

[0013] In some embodiments, the organic solvent is selected from at least one of diethylene glycol butyl ether, propylene glycol methyl ether, ethylene glycol propyl ether, ethylene glycol dimethyl ether, diisopropyl ether.

[0014] In some embodiments, the diameter of the diamond wire is 30-32 μm; and / or

[0015] The average diameter of the silicon wafer is 182-210 mm.

[0016] In some embodiments, the application further provides a preparation method of the large silicon wafer cutting liquid, comprising:

[0017] The components are weighed according to the respective mass fractions;

[0018] The lubricant is first dissolved in the organic solvent, and then the wetting agent, the preservative, and the deionized water are sequentially added. The addition process is continuously stirred, the stirring temperature is controlled to be 20-45℃, the stirring time is 3-5 h, until the components are completely dissolved, and then the cutting liquid is obtained by standing and filtering.

[0019] In some embodiments, the application further provides the use of the large silicon wafer cutting liquid in fine wire cutting of solar silicon wafers.

[0020] Compared with the prior art, the application has the following beneficial effects: in the large silicon wafer cutting liquid of the application, the lubricant and the preservative are used, and protective films can be respectively formed on the surface of the silicon wafer and the surface of the diamond wire, so that the cutting of the fine wire diameter diamond wire is realized, and the advantages of safety, environmental protection, cleanliness, high wetting dispersion, and no corrosion to the solar silicon wafer are achieved; the existence of the protective film reduces the problem of dirt and wire marks caused by the direct contact between the silicon wafer and the diamond wire, and avoids the wire breakage of the diamond wire; the existence of the adsorption film can also slow down the corrosion speed of the diamond wire material, and further reduce the wire breakage rate.

[0021] It can be understood that the preparation method of the large silicon wafer cutting liquid and the use of the large silicon wafer cutting liquid provided by the embodiments of the present application have all the technical features and beneficial effects of the large silicon wafer cutting liquid described above compared with the prior art, which will not be described here. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0023] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. In the description of the present application, the meaning of "multiple" is two or more than two, unless otherwise explicitly specified and limited. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more features.

[0024] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0025] Applicants find that with the continuous development and maturity of solar photovoltaic industry technology, the demand for silicon wafers is growing rapidly. Slicing is the first process of silicon wafer deep processing, and silicon wafer accounts for 30-40% of the cost of solar photovoltaic module, so the improvement of silicon wafer technology is of great significance to reduce the cost of module. In recent years, the specifications of silicon wafers are also being optimized. The increase in size and the thinning of silicon wafers have become the mainstream technical direction, which not only can effectively reduce the cost, but also can maximize the efficiency of the module. At the same time, in order to adapt to the change of silicon wafer size and improve the cutting efficiency, the wire diameter of diamond wire also develops to a finer wire diameter.

[0026] Solar silicon wafer cutting is mainly based on diamond wire cutting, which has the advantages of high efficiency, low cost, environmental protection and so on. Silicon wafer is a hard material, and a large amount of heat and wear will be generated during diamond wire cutting, which is easy to cause problems such as wire breakage, wire marks and TTV. With the development of large-size and thin wafer cutting and the thinning of diamond wire, higher requirements are put forward for the performance of the cutting fluid to adapt to the cutting of thin wire and improve the yield. The thin wire diameter diamond wire cutting fluid has problems such as dirt, wire marks and wire breakage rate. Therefore, a safe, environmentally friendly, clean, high wetting and dispersing, non-corrosive cutting fluid for solar silicon wafer is needed, which can be applied to the cutting of thin wire diameter diamond wire.

[0027] The embodiment of the present application provides a large silicon wafer cutting fluid, which is applied to diamond wire cutting of silicon wafer. The cutting fluid comprises the following components in mass parts: 20-40 parts of wetting agent, 1-10 parts of lubricant, 0.1-2 parts of preservative, 20-40 parts of deionized water and 5-20 parts of organic solvent; wherein the lubricant is used to form a protective film on the surface of the silicon wafer, and the preservative is used to form an adsorption film on the surface of the diamond wire.

[0028] It can be understood that the cutting fluid of the embodiment adopts lubricant and preservative, and can form protective film on the surface of the silicon wafer and adsorption film on the surface of the diamond wire respectively, so as to realize the cutting of thin wire diameter diamond wire; the existence of the protective film reduces the friction between the diamond wire and the silicon wafer, which can reduce the wear and heat generation during cutting, prolong the service life of the diamond wire and the silicon wafer, and also reduce the problems of dirt and wire marks caused by direct contact between the silicon wafer and the diamond wire, and avoid the breakage of the diamond wire; the existence of the adsorption film can also slow down the corrosion speed of the diamond wire material and further reduce the breakage rate.

[0029] Further, the wetting agent can reduce the surface tension of the liquid, so that the cutting fluid is more easily contacted and covered with the silicon wafer, which can effectively improve the cutting efficiency and quality; the deionized water is a basic solvent of the cutting fluid, which is used to dilute and adjust the concentration of the cutting fluid; the organic solvent acts as a carrier for dissolving other components, and plays a role of dissolving and diluting in the cutting fluid; and the appropriate amount of organic solvent can adjust the viscosity of the cutting fluid.

[0030] In some embodiments, at least one of the lubricant and the preservative has an amide group.

[0031] Further, the lubricant and the preservative both have amide groups. It can be understood that when the preservative and the lubricant both contain amide groups, the molecules on the protective film and the adsorption film are more closely arranged through intermolecular hydrogen bonds or dipole moment interactions, so as to increase the viscosity and elasticity of the protective film or the adsorption film, enhance the stability of the protective film and the adsorption film, and play a protective role on the diamond wire and the silicon wafer.

[0032] In some embodiments, the cutting liquid, in parts by mass, preferably includes 30-35 parts of a wetting agent, 1-5 parts of a lubricant, 0.5-1 part of a preservative, 30-40 parts of deionized water, and 10-15 parts of an organic solvent.

[0033] In some embodiments, the lubricant is selected from at least one of stearamidopropyl dimethylamine, oleamide, erucamide, and stearamide.

[0034] It should be noted that using the above-mentioned lubricant, when contacting the surface of the silicon wafer during the cutting process, the hydrophilic group faces the surface of the silicon wafer, and the hydrophobic group faces the air, forming a protective film on the surface of the silicon wafer. When in contact with the diamond wire, it can effectively reduce friction and reduce the problem of wire marks and broken wires. Due to the amide group in its molecular structure, it has good anti-static ability, so that silicon powder is not easy to adhere to the surface of the silicon wafer, which can effectively improve the dirt rate. At the same time, the long molecular chain of the lubricant can make the two friction surfaces of the silicon wafer and the diamond wire far away, and the lubrication effect is better and the lubrication efficiency is high.

[0035] In some embodiments, the CAS number of stearamidopropyl dimethylamine is 7651-02-7, the molecular formula is C 23 H 48 N2O, and the structural formula is:

[0036] In some embodiments, the CAS number of oleamide is 301-02-0, the molecular formula is C 18 H 35 NO, and the structural formula is:

[0037] In some embodiments, the CAS number of erucamide is 112-84-5, the molecular formula is C 22 H 43 NO, and the structural formula is:

[0038] In some embodiments, the CAS number of stearamide is 124-26-5, the molecular formula is C 18 H 37 NO, and the structural formula is:

[0039] In some embodiments, stearamidopropyl dimethylamine, oleamide, erucamide, and stearamide can be obtained through commercial channels, and will not be described in detail here.

[0040] In some embodiments, the lubricant is preferably stearamidopropyl dimethylamine.

[0041] In some embodiments, the preservative is selected from fatty acyl amino acid surfactants.

[0042] It should be noted that the fatty acyl amino acid surfactant can be adsorbed on the diamond wire to form an adsorption film, thereby changing the charge state and interface properties of the metal layer (such as the nickel layer) on the surface of the diamond wire, making the surface energy state of the metal layer tend to be stable, improving the activation energy of the corrosion reaction, slowing down the corrosion speed, and playing an effective corrosion inhibition effect, and can effectively reduce the wire breaking rate; in addition, the hydrophobic group in the fatty acyl amino acid surfactant is large, the area covered by the adsorption film on the metal is larger, and the adsorption film is more firm due to the van der Waals force between the hydrophobic chains, and the corrosion inhibition effect is better.

[0043] In some embodiments, the preparation of the fatty acyl amino acid surfactant includes acyl chloride method, fatty acid anhydride method, fatty nitrile hydrolysis method, amide carbonylation method, enzyme method, etc.

[0044] In some embodiments, a preparation process of a fatty acyl amino acid surfactant is provided, including the following steps: first, weigh fatty acid methyl ester and amino acid salt and mix them in a stirring device, then after sufficient mixing, a mixed solution is formed; then the mixed solution is moved to a reaction kettle, a catalyst is added, and then the reaction is carried out under heating to obtain the fatty acyl amino acid surfactant. In the process, the molar ratio of the fatty acid methyl ester to the amino acid salt is 1:1-2.5, the reaction temperature is 120-150°C, and the reaction time is 4-6h.

[0045] In some embodiments, the carbon chain length of the fat in the fatty acyl amino acid surfactant is C 10 -C 20 As can be seen from the above preparation process, the carbon chain length of the fat referred to here is actually the carbon chain length of the raw material, such as the carbon chain length of the fatty acid methyl ester. Of course, in other preparation processes, the carbon chain length is based on the carbon chain length of the aliphatic compound raw material used.

[0046] In some embodiments, the amino acid in the fatty acyl amino acid surfactant is selected from at least one of glutamic acid, glycine, alanine and sarcosine. The amino acid referred to here can be based on the amino acid or amino acid salt used in the raw materials of the preparation process.

[0047] In some embodiments, the fatty acyl amino acid surfactant is water-soluble.

[0048] In some embodiments, the fatty acyl amino acid surfactant is selected from at least one of sodium lauroyl glutamate, sodium lauroyl glycinate, sodium lauroyl alaninate, sodium lauroyl sarcosinate, sodium cocoyl glycinate, sodium cocoyl glutamate and sodium stearoyl glutamate.

[0049] In some embodiments, the CAS number of sodium lauroyl glutamate is: 29923-31-7, and the molecular formula is: C 17 H30 NNaO5.

[0050] In some embodiments, the CAS number of sodium lauroyl glycinate is: 18777-32-7, and the molecular formula is: C 14 H 26 NNaO3.

[0051] In some embodiments, the CAS number of sodium lauroyl alaninate is: 55535-58-5, and the molecular formula is: C 15 H 28 NNaO3.

[0052] In some embodiments, the CAS number of sodium lauroyl sarcosinate is: 137-16-6, and the molecular formula is: C 15 H 28 NNaO3.

[0053] In some embodiments, the CAS number of sodium cocoyl glycinate is: 90387-74-9.

[0054] In some embodiments, the CAS number of sodium cocoyl glutamate is: 68187-32-6.

[0055] In some embodiments, the CAS number of sodium stearoyl glutamate is: 38517-23-6.

[0056] In some embodiments, sodium lauroyl glutamate, sodium lauroyl glycinate, sodium lauroyl alaninate, sodium lauroyl sarcosinate, sodium cocoyl glycinate, sodium cocoyl glutamate and sodium stearoyl glutamate, etc. can be purchased through commercial channels, and will not be described in detail here.

[0057] In some embodiments, the wetting agent is a fatty alcohol polyoxyethylene polyoxypropylene ether, and the chemical formula is RO(CH2CH2O) m (C3H6O) n H, wherein R is selected from C3-C8 hydrocarbon group; m represents the addition number of ethylene oxide groups, and is selected from an integer from 2 to 8; n represents the addition number of propylene oxide groups, and is selected from an integer from 4 to 10.

[0058] It can be understood that the ether bond in the wetting agent molecule is not easily destroyed by acid or base, so the stability is relatively high, the water solubility is relatively good, the electrolyte resistance is good, the biodegradation is easy, and the foam is small; the molecular weight of the wetting agent is relatively small, and the number of propylene oxide polymerization is more than that of ethylene oxide, which ensures good wettability and permeability, and can provide higher cutting capacity in the cutting process.

[0059] Further, due to the large hydrophobic group of the lubricant, the water solubility deviates, while the fatty alcohol polyoxyethylene ether has a certain solubilizing effect on it, which can effectively improve the water solubility of the system, reduce the agglomeration of silicon powder, and reduce the dirt rate.

[0060] In some embodiments, the fatty alcohol polyoxyethylene polyoxypropylene ether can be obtained by commercial channels, and will not be described in detail here.

[0061] In some embodiments, the molecular weight of the wetting agent is 364-1046.

[0062] In some embodiments, the organic solvent is selected from at least one of diethylene glycol butyl ether, propylene glycol methyl ether, ethylene glycol propyl ether, ethylene glycol dimethyl ether, diisopropyl ether. It can be understood that the organic solvent can further help the lubricant to dissolve and improve the water solubility of the whole system. At the same time, during the cutting process, with the circulation of the filter and the replenishment of the liquid, it can be continuously enriched on the surface of the silicon wafer to improve the wettability in the second half of the cutting process.

[0063] In some embodiments, the diameter of the diamond wire is 30μm-32μm; for example, the diameter of the diamond wire can be any one value or a range between any two values of 30μm, 31μm, 32μm.

[0064] In some embodiments, the average diameter of the silicon wafer is 182mm-210mm; for example, the average diameter of the silicon wafer can be any one value or a range between any two values of 182mm, 183mm, 185mm, 188mm, 190mm, 192mm, 195mm, 198mm, 200mm, 202mm, 205mm, 208mm, 210mm.

[0065] In some embodiments, a preparation method of a large silicon wafer cutting liquid is provided, comprising: weighing the respective mass fractions of the components; first dissolving the lubricant in the organic solvent, then sequentially adding the wetting agent, the preservative and the deionized water, continuously stirring during the addition process, controlling the stirring temperature to be 20-45℃, and the stirring time to be 3-5h, until all the components are completely dissolved, then standing, filtering, to obtain the cutting liquid.

[0066] In some embodiments, the use of the large silicon wafer cutting liquid in the fine wire cutting of solar silicon wafers is provided. In particular, the use in the field of cutting large-size solar silicon wafers, the size of the solar silicon wafer being 182mm-210mm.

[0067] The large silicon wafer cutting liquids of embodiments 1-6 are provided respectively, and the specific components are shown in Table 1.

[0068] Table 1

[0069]

[0070]

[0071] The cutting liquid for large silicon wafers of Comparative Examples 1-4 was provided, and the specific components are shown in Table 2.

[0072] Table 2

[0073]

[0074]

[0075] Among them, Comparative Example 1 did not add a wetting agent compared with Example 1; Comparative Example 2 did not add a lubricant compared with Example 1; Comparative Example 3 did not add a preservative compared with Example 1; and Comparative Example 4 did not add an organic solvent compared with Example 1.

[0076] The method for preparing the cutting liquid in each of the above examples and comparative examples was similar, specifically: weighing the components in respective mass fractions; sequentially mixing the lubricant, the organic solvent, the wetting agent, the preservative, and the deionized water (components not contained in the comparative examples were not added), continuously stirring during the addition process, controlling the stirring temperature to be 30°C, and stirring for 4h, until each component was completely dissolved, then standing, filtering, and obtaining the cutting liquid.

[0077] The performance of the large silicon wafer cutting liquid of Examples 1-6 and Comparative Examples 1-4 was compared, and the specific results are shown in Table 3.

[0078] Table 3

[0079] Example / Comparative Example Grade A Yield Grade B Yield Breakage Rate Scratch Dirt Rate Example 1 98.24％ 99.15％ 2.24％ 0.58％ 0.45％ Example 2 98.06％ 98.87％ 2.44％ 0.77％ 0.49％ Example 3 98.13％ 98.57％ 3.02％ 0.71％ 0.63％ Example 4 97.34％ 98.44％ 3.11％ 0.61％ 0.51％ Example 5 97.55％ 98.63％ 2.98％ 0.82％ 0.72％ Example 6 97.73％ 98.68％ 3.58％ 0.81％ 0.66％ Comparative Example 1 80.47％ 91.26％ 6.77％ 10.77％ 5.24％ Comparative Example 2 81.56％ 92.41％ 5.38％ 6.11％ 9.33％ Comparative Example 3 95.41％ 97.03％ 17.67％ 2.01％ 1.37％ Comparative Example 4 95.13％ 96.34％ 15.83％ 1.45％ 1.98％

[0080] Among them, the A-grade yield refers to the proportion of the number of silicon wafers completely meeting the shipment standard to the total number of cut silicon wafers. The B-grade yield refers to the proportion of the number of silicon wafers completely meeting the shipment standard and the number of silicon wafers with slight defects but not affecting shipment to the total number of silicon wafers. The broken wire rate refers to the proportion of the number of knives with broken wires during cutting to the total number of knives on the same machine. The line mark refers to a scratch line, mainly caused by the aggregation of silicon powder between the diamond wire and the silicon wafer, which cannot overflow and cause line marks. The line mark value refers to the proportion of the number of silicon wafers with line mark problems to the total number of silicon wafers. The average thickness of the silicon wafer is tested, and if it exceeds a certain value, it is determined that the silicon wafer has a line mark problem. This data is measured by the machine and directly calculated as a percentage. The dirt rate refers to the proportion of the number of silicon wafers with obvious silicon powder aggregation that is not easy to clean to the total number of silicon wafers.

[0081] As can be seen from Table 3, the broken wire rate of Examples 1-6 is significantly lower than that of the comparative examples, which proves that the addition of the preservative can effectively protect the diamond wire and prevent broken wires. In addition, from the line mark and dirt rate, it can be seen that the addition of the lubricant can effectively protect the surface of the silicon wafer and prevent the adhesion of silicon powder on the silicon wafer, thereby making the surface of the silicon wafer cleaner.

[0082] The above describes in detail a large silicon wafer cutting liquid, a preparation method and use thereof provided by the embodiments of the present application. The principles and implementation manners of the present application are described by using specific examples. The above descriptions of the embodiments are only used to help understand the technical solutions and core ideas of the present application. Those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A large silicon wafer cutting fluid applied to diamond wire cutting silicon wafer, characterized in that, The cutting liquid comprises the following components in parts by mass: 20-40 parts of a wetting agent, 1-10 parts of a lubricant, 0.1-2 parts of a preservative, 20-40 parts of deionized water, and 5-20 parts of an organic solvent; The lubricant is used to form a protective film on the surface of the silicon wafer, and the preservative is used to form an adsorption film on the surface of the diamond wire; The lubricant is selected from at least one of stearamidopropyl dimethylamine, oleic acid amide, erucic acid amide, and stearamide; The preservative is selected from at least one of sodium lauroyl glutamate, sodium lauroyl glycinate, sodium lauroyl alaninate, sodium lauroyl sarcosinate, sodium cocoyl glycinate, sodium cocoyl glutamate, and sodium stearyl glutamate; The wetting agent is a fatty alcohol polyoxyethylene polyoxypropylene ether, chemical formula is RO(CH2CH2O) m (C3H6O) n H, wherein R is selected from C3-C8 hydrocarbon group; m represents the addition number of ethylene oxide group, selected from an integer from 2 to 8; n represents the addition number of propylene oxide group, selected from an integer from 4 to 10; The organic solvent is selected from at least one of diethylene glycol butyl ether, propylene glycol methyl ether, ethylene glycol propyl ether, ethylene glycol dimethyl ether, and diisopropyl ether.

2. The bulk silicon wafer sawing solution of claim 1, wherein The diameter of the diamond wire is 30-32 μm; and / or The average diameter of the silicon wafer is 182-210 mm.

3. The method of preparing a dicing solution for large silicon wafers according to claim 1 or 2, characterized by, The method comprises the following steps: Weighing the components in parts by mass; First, the lubricant is dissolved in the organic solvent, and then the wetting agent, preservative, and deionized water are added in sequence. The addition process is continuously stirred, the stirring temperature is controlled at 20-45°C, the stirring time is 3-5 h, until all components are completely dissolved, then stand, filter, to obtain the cutting liquid.

4. Use of the cutting liquid for large silicon wafers according to any one of claims 1-3 in fine wire cutting of solar silicon wafers.

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