Modified polycarboxylate and preparation method thereof, water-based cutting fluid containing the same and application of the water-based cutting fluid

Abstract

The present application belongs to the field of silicon wafer cutting technology, and specifically relates to a modified polycarboxylate and a preparation method thereof, a water-based cutting fluid containing the same, and an application of the water-based cutting fluid. The modified polycarboxylate provided in the present application includes a structural unit A and a structural unit B. The water-based cutting fluid provided in the present application includes the above-mentioned modified polycarboxylate, a pH regulator, a polyol, and water. The water-based cutting fluid of the present application has stable performance, is easy to store, is environmentally friendly, and can effectively improve the dispersibility of the mortar during the cutting process.

Description

Technical Field

[0001] The present application relates to the technical field of silicon wafer cutting, and in particular to a modified polycarboxylate and a preparation method thereof, a water-based cutting fluid containing the modified polycarboxylate, and applications of the water-based cutting fluid. Background Art

[0002] When cutting semiconductor silicon wafers, the cutting fluid is required to have excellent heat dissipation performance during the cutting process and be able to effectively suspend and disperse abrasives such as silicon carbide into the cutting mortar to reduce friction resistance during the cutting process.

[0003] Cutting fluids used for cutting semiconductor silicon wafers mainly include water-based cutting fluids and oil-based cutting fluids. Oil-based cutting fluids have poor water solubility and lubricity. In comparison, water-based cutting fluids have better cooling, lubricity and dispersibility. However, the performance of existing water-based cutting fluid products is not stable enough, and they are prone to spoilage during storage, causing waste. In addition, the use of a large amount of defoamers and surfactants in the formula leads to high COD values ​​in the cutting fluid, which pollutes the environment. In addition, traditional cutting fluid formulas also have problems with poor dispersibility and suspension performance.

[0004] Therefore, developing a water-based cutting fluid that has excellent dispersibility and environmental protection performance and is stable and easy to store is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present application is to provide a modified polycarboxylate, which is used in a water-based cutting fluid, so that the water-based cutting fluid has stable performance, is easy to store, and is environmentally friendly. When used in silicon wafer cutting, it can effectively improve the dispersibility of mortar during the cutting process.

[0006] In a first aspect of the present application, a modified polycarboxylate is provided, which comprises a structural unit A and a structural unit B, wherein the structural formulas of the structural unit A and the structural unit B are as follows:

[0007]

[0008] in,

[0009] R2 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms, -COOR1 or -COOM;

[0010] Each R1 is the same or different and is independently selected from an alkyl group having 6 to 20 carbon atoms;

[0011] R3 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms or -COOM;

[0012] M is selected from monovalent metal cations.

[0013] The second aspect of the present application provides a method for preparing the modified polycarboxylate described in the first aspect, comprising:

[0014] Carrying out a partial carboxyl activation reaction on the polycarboxylic acid to obtain a partially carboxyl activated polycarboxylic acid;

[0015] The polycarboxylic acid with partially activated carboxyl groups is subjected to an esterification reaction with an alcohol substance to obtain an esterification product;

[0016] reacting the remaining carboxyl groups in the esterification product with a metal oxide or a metal hydroxide to obtain the modified polycarboxylate;

[0017] The structural unit contained in the polycarboxylic acid is shown in Formula I, and the structural formula of the alcohol substance is shown in Formula II:

[0018]

[0019] R4 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms or -COOH; R1 has the same definition as in the first aspect of the present application.

[0020] The third aspect of the present application provides a water-based cutting fluid, which comprises the modified polycarboxylate described in the first aspect of the present application, a pH regulator, a polyol and water.

[0021] According to a fourth aspect of the present application, there is provided a use of the water-based cutting fluid described in the third aspect of the present application in cutting semiconductor silicon wafers.

[0022] Technical effects of this application:

[0023] 1. The present application uses a chemical modification method to graft an alkyl chain segment with a carbon number of 6 to 20 into the polycarboxylate, which not only improves the dispersibility of the polycarboxylate, but also gives it the characteristics of a surfactant. The modified polycarboxylate of the present application is applied to the cutting fluid, and no additional surfactant is required to be added to the cutting fluid. The omission of the surfactant can greatly reduce the generation of bubbles during the cutting process, so that there is no need to use a defoaming agent in the cutting fluid, and also reduces the dependence of the cutting fluid component on the organic solvent formulation design, forming a water-based cutting fluid formulation system, reducing costs while reducing environmental pollution.

[0024] 2. The water-based cutting fluid of the present application has a larger specific heat capacity, and therefore has better cooling properties, so that the heat generated during the cutting process can be promptly discharged, so that the silicon wafer is not easily deformed during the cutting process. In addition, the water-based cutting fluid of the present application has a low COD value and is environmentally friendly; it has good wetting properties and is easy to clean. The mortar prepared with the water-based cutting fluid has good dispersibility and suspension, which is conducive to improving the yield of silicon wafer cutting.

[0025] 3. The water-based cutting fluid of the present application has good stability and can be stably stored for one and a half years without deterioration. The dispersant of the present application is compounded with modified polycarboxylate and other components to improve the stability of the water-based cutting fluid and extend the storage period. DETAILED DESCRIPTION

[0026] The exemplary embodiments will be described more fully below. However, the exemplary embodiments can be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein; rather, these embodiments are provided so that the present application will be more comprehensive and complete and the concepts of the exemplary embodiments will be fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application.

[0027] In a first aspect, the present application provides a modified polycarboxylate, which comprises a structural unit A and a structural unit B, wherein the structural formulas of the structural unit A and the structural unit B are as follows:

[0028]

[0029] in,

[0030] R2 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms, -COOR1 or -COOM;

[0031] Each R1 is the same or different and is independently selected from an alkyl group having 6 to 20 carbon atoms;

[0032] R3 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms or -COOM;

[0033] M is selected from monovalent metal cations.

[0034] In the present application, the alkyl group having 6 to 20 carbon atoms may include a straight-chain alkyl group having 6 to 20 carbon atoms and a branched-chain alkyl group having 6 to 20 carbon atoms, and the number of carbon atoms thereof may be, for example, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20. Specific examples thereof include, but are not limited to, n-hexyl, isohexyl, 3-methylpentyl, 2,2-dimethylbutyl, n-octyl, isooctyl, n-heptyl, n-undecyl, isomeric dodecyl, isomeric tridecyl, n-pentadecyl, n-eicosyl, and the like.

[0035] In the present application, specific examples of the alkyl group having 1 to 4 carbon atoms include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl.

[0036] In some embodiments, R1 is selected from an alkyl group with 8 to 15 carbon atoms, including a straight-chain alkyl group with 8 to 10 carbon atoms, a branched-chain alkyl group with 8 to 10 carbon atoms, a straight-chain alkyl group with 11 to 13 carbon atoms, a branched-chain alkyl group with 11 to 13 carbon atoms, a straight-chain alkyl group with 14 to 15 carbon atoms, a branched-chain alkyl group with 14 to 15 carbon atoms, and the like.

[0037] In some embodiments, R1 is selected from n-octyl, isooctyl, n-undecyl, isomeric dodecyl, and isomeric tridecyl.

[0038] In some embodiments, R2 is selected from hydrogen, methyl, ethyl, -COOR1 or -COOM.

[0039] In some embodiments, R2 is hydrogen or methyl.

[0040] In some embodiments, R3 is selected from hydrogen, methyl, ethyl or -COOM.

[0041] In some embodiments, R3 is hydrogen or methyl.

[0042] In some embodiments, M is selected from Na + or K + .

[0043] In some embodiments, the ratio of the number of structural unit A to structural unit B is 1:4 to 3: 1. In some embodiments, the ratio of the number of structural unit A to structural unit B is 2.5:10 to 20:10, 3.3:10 to 4.2:10. In some embodiments, the number ratio of structural unit A to structural unit B is 2.5:10, 3:10, 3.3:10, 1:3, 3.5:10, 4:10, 4.2:10, 4.5:10, 5:10, 5.5:10, 6:10, 6.5:10, 7:10, 7.5:10, 8:10, 8.5:10, 9:10, 9.5:10, 10:10, 11:10, 12:10, 13:10, 14:10, 15:10, 16:10, 17:10, 18:10, 19:10, 20:10 or any value therebetween. In some embodiments, the number ratio of structural unit A to structural unit B is 3:10 to 5:10, for example, 3.3:10, 1:3, 4:10 or 4.2:10.

[0044] In some embodiments, the weight average molecular weight of the modified polycarboxylate is 1500-6500, for example, 1500, 1700, 2000, 2300, 2500, 2700, 3000, 3300, 3500, 3700, 4000, 4300, 4500, 4700, 5000, 5600, 6000, 6300, 7500 or any value therebetween. In some embodiments, the weight average molecular weight of the modified polycarboxylate is 2000-4500.

[0045] The modified polycarboxylates described in the present application, on the one hand, the introduction of alkyl groups can change the hydrophilic and hydrophobic properties of polycarboxylates, and the two are combined in a corresponding ratio to achieve the graft modification of polycarboxylates, so that the modified polycarboxylates have amphiphilic properties, and at the same time have excellent dispersibility, and can efficiently disperse abrasive particles. At the same time, the introduction of alkyl groups also makes the modified polycarboxylates have the characteristics of surfactants. On the other hand, by utilizing the structural characteristics of the amphiphilic chemical chains in the modified polycarboxylates, the dispersibility of abrasive particles in aqueous solution can be increased, and the hydrophilic interface formed by the micelles after dispersion can form a strong interaction with water molecules, reduce the adsorption force between particles, and prevent particles from agglomerating. The carboxylate group will be anionized, release negative charges, and make the particle surface carry negative charges. This negative charge can generate electrostatic repulsion, and can further prevent the aggregation between particles, which is helpful for the suspension and dispersion of abrasive particles in the cutting fluid system.

[0046] The second aspect of the present application provides a method for preparing a modified polycarboxylate, comprising the following steps:

[0047] Step S1: performing a partial carboxyl activation reaction on the polycarboxylic acid to obtain a partially carboxyl activated polycarboxylic acid;

[0048] Step S2: subjecting the polycarboxylic acid partially activated by carboxyl groups in step S1 to an esterification reaction with an alcohol substance to obtain an esterification product;

[0049] Step S3: reacting the remaining carboxyl groups in the esterification product in step S2 with a metal oxide or a metal hydroxide to obtain the modified polycarboxylate;

[0050] The structural unit contained in the polycarboxylic acid is shown in Formula I, and the structural formula of the alcohol substance is shown in Formula II:

[0051]

[0052] R1-OH Formula II;

[0053] Among them, R1 is selected from an alkyl group having 6 to 20 carbon atoms; R4 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms or -COOH.

[0054] In some embodiments, in Formula I, R4 is selected from hydrogen, methyl, ethyl or -COOH.

[0055] In some embodiments, the polycarboxylic acid represented by Formula I is selected from one or more of polyacrylic acid, polymethacrylic acid or polymaleic acid.

[0056] In some embodiments, the weight average molecular weight of the polycarboxylic acid is 1000-5000, preferably 1500-3000, for example, 1500, 1700, 2000, 2300, 2500, 2600, 3000 or any value therebetween.

[0057] In formula II, R1 has the same definition as in the modified polycarboxylate disclosed in the first aspect of the present application.

[0058] In some embodiments, in step S1, N,N'-dicyclohexylcarbodiimide is used as a carboxyl activator to perform a partial carboxyl activation reaction on the polycarboxylic acid. In some embodiments, the molar ratio of the carboxyl activator to the carboxyl group in the polycarboxylic acid is 1:1 to 1:10. In some embodiments, the molar ratio of the carboxyl activator to the carboxyl group in the polycarboxylic acid is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8 or 1:9. In some more specific embodiments, in step S1, the carboxyl activator is N,N'-dicyclohexylcarbodiimide, and the molar ratio of the carboxyl group to all the carboxyl groups in the polycarboxylic acid is 1:3.38 to 1:4, for example, 1:3.38, 1:3.45 or 1:4.

[0059] In some embodiments, in step S1, the temperature of the carboxyl activation reaction is 65° C. to 75° C., and the time of the carboxyl activation reaction is 10 hours to 48 hours.

[0060] In some embodiments, when a single alcohol substance is used in step S2, each R1 is the same; when a mixed alcohol substance is used in step S2, each R1 is the same or different.

[0061] In some embodiments, the alcohol substance is selected from one or more of n-hexanol, isohexanol, 3-methylpentanol, 2,2-dimethylbutanol, n-octanol, isooctyl alcohol, n-heptanol, n-undecanol, isomeric dodecanol, isomeric tridecanol, n-pentadecanol or n-eicosanol.

[0062] In some embodiments, in step S2, the amount of the alcohol substance used is the same as the molar amount of the carboxyl activator in step S1. That is, the molar ratio of the amount of the alcohol substance used to the carboxyl group in the polycarboxylic acid in step S1 is 1:1 to 1:10. For example, it is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8 or 1:9. In some more specific embodiments, in step S2, the molar ratio of the alcohol substance to the carboxyl group in the polycarboxylic acid in step S1 is 1:3.38 to 1:4, for example, 1:3.38, 1:3.45 or 1:4.

[0063] In some embodiments, in step S3, the metal oxide or metal hydroxide is selected from one or more of NaOH, KOH, Na2O, and K2O.

[0064] In some embodiments, in step S2, the temperature of the esterification reaction is 65° C. to 75° C., and the time of the esterification reaction is 10 hours to 48 hours.

[0065] In some embodiments, in step S3, the esterification product in step S2 is subjected to a solution reaction with a metal oxide or hydroxide, and the solvent is removed after the reaction until the solution system becomes weakly alkaline to obtain the modified polycarboxylate.

[0066] In some embodiments, the weak alkalinity in step S3 means that the pH value of the solution system is 8-10.

[0067] The third aspect of the present application provides a water-based cutting fluid, which includes the modified polycarboxylate described in the first aspect, a pH regulator, a polyol and water.

[0068] In some embodiments, the pH regulator is selected from one or more of hydrochloric acid, nitric acid, sulfuric acid, sodium carbonate, potassium carbonate sodium salt, citric acid and succinic acid, wherein the molar concentration of hydrochloric acid is 0.2M to 5M, the molar concentration of nitric acid is 0.2M to 5M, and the molar concentration of sulfuric acid is 0.1M to 5M.

[0069] In some embodiments, the pH adjuster is selected from one or more of 1M hydrochloric acid, 2M hydrochloric acid, 5M hydrochloric acid, 1M nitric acid, 2M nitric acid, 5M nitric acid, 0.5M sulfuric acid, 1M sulfuric acid, 2M sulfuric acid, 5M sulfuric acid, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, citric acid and succinic acid.

[0070] In some embodiments, the polyol is selected from one or more diols having 2 to 6 carbon atoms, and specific examples thereof include but are not limited to ethylene glycol, propylene glycol, butanediol, and the like.

[0071] In some embodiments, the polyol is selected from one or both of ethylene glycol and propylene glycol.

[0072] In some embodiments, based on the mass of the water-based cutting fluid, the mass percentage of the modified polycarboxylate is 1% to 15%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13% or 14%. In some embodiments, the mass percentage of the modified polycarboxylate is 5% to 10%.

[0073] In some embodiments, based on the mass of the water-based cutting fluid, the mass percentage of the pH regulator is 0.5% to 10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%. In some embodiments, the mass percentage of the pH regulator is 1% to 5%.

[0074] In some embodiments, based on the mass of the water-based cutting fluid, the mass percentage of the polyol is 5% to 60%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% or 55%. In some embodiments, the mass percentage of the polyol is 10% to 55%.

[0075] In some embodiments, based on the mass of the water-based cutting fluid, the mass percentage of water is 20% to 80%, for example, 25%, 30%, 34%, 35%, 40%, 45%, 50%, 54%, 55%, 60%, 65%, 70%, 75% or 80%. In some embodiments, the mass percentage of water is 34% to 80%.

[0076] In a fourth aspect, the present application provides the use of the water-based cutting fluid described in the third aspect in cutting semiconductor silicon wafers.

[0077] Synthesis Example

[0078] It should be recognized by professionals in the field that the chemical reactions described in this application can be used to appropriately prepare many of the materials of this application, and other methods for preparing the materials of this application are considered to be within the scope of this application. For example, the synthesis of non-exemplified compounds according to this application can be successfully completed by technicians in the field through modification methods, such as appropriate protection of interfering groups, by utilizing other known reagents in addition to those described in this application, or by making some conventional modifications to the reaction conditions. The compounds for which the synthesis method is not mentioned in this application are all raw materials obtained through commercial channels. The synthesis method of the modified polycarboxylate of this application is specifically described in conjunction with the synthesis examples below, but this application is not subject to any limitation thereto.

[0079] Synthesis example 1

[0080] Carboxyl activation reaction: Take a 200mL three-necked flask, remove water and oxygen, add polyacrylic acid (10g, 0.005mol) (Mw=2000), and then add 50mL chloroform, stir until completely dissolved, and obtain mixed solution H. Take N,N'-dicyclohexylcarbodiimide (DCC) (0.040mol, 7.95g) and fully dissolve it in 50mL chloroform to obtain mixed solution Q. Heat the mixed solution H to 70℃, then drip the mixed solution Q very slowly, keep 70℃ for carboxyl activation, and fully react for 15h. After the reaction is completed, it is recorded as product A and wait for the next reaction.

[0081] Hydroxyl esterification reaction: Dissolve octanol (0.04 mol, 5.2 g) in 50 mL of chloroform to obtain a mixed solution W. Transfer product A to a 250 mL reaction bottle, heat to 70°C, slowly dropwise add the mixed solution W, and maintain 70°C for esterification after the addition is complete. After 24 hours of reaction, take out, evaporate most of the chloroform, and then precipitate the product with a large amount of petroleum ether, suck out the supernatant layer, separate the product layer, dissolve the product layer with chloroform again, and then evaporate the solvent to obtain product B.

[0082] Product B was dissolved in 100 mL of water, and NaOH was slowly added at room temperature to adjust the pH value to 9. After the reaction was completed, the product was dried to obtain a modified polyacrylic acid sodium salt, which was recorded as product 1.

[0083] Product 1 includes structural unit A and structural unit B The ratio of the number of structural unit A to that of structural unit B is 4:10.

[0084] Synthesis example 2

[0085] Carboxyl activation reaction: Take a 200mL three-necked flask, remove water and oxygen, add polymaleic acid (10g, 0.004mol) (Mw=2500), and then add 50mL chloroform, stir until completely dissolved, and obtain mixed solution H. Take N,N'-dicyclohexylcarbodiimide (DCC) (0.043mol, 8.88g) and fully dissolve it in 50mL chloroform to obtain mixed solution Q. Then heat the mixed solution H to 75℃, and then very slowly drop it into the mixed solution Q. Keep the carboxyl activation at 75℃, and fully react for 48h. After the reaction is completed, it is recorded as product A and wait for the next reaction.

[0086] Hydroxyl esterification reaction: Dissolve isomeric tridecanol (0.043 mol, 8.6 g) in 50 mL of chloroform to obtain a mixed solution W. Transfer product A to a 250 mL reaction bottle, heat to 75 °C and slowly dropwise add the mixed solution W. After the addition is complete, maintain 75 °C for esterification. After 10 hours of reaction, remove the mixture, evaporate most of the chloroform, and then precipitate the product with a large amount of petroleum ether, suck out the supernatant layer, separate the product layer, and dissolve the product layer again with chloroform, and then evaporate the solvent to obtain product B.

[0087] Product B was dissolved in 100 mL of water, and NaOH was slowly added at room temperature to adjust the pH value to 9. After the reaction was completed, the product was dried to obtain the modified polymaleic acid sodium salt, which was recorded as product 2.

[0088] Product 2 includes structural unit A and structural unit B Among them, the quantity ratio of structural unit A to structural unit B is 3.3:10.

[0089] Synthesis example 3

[0090] Carboxyl activation reaction: Take a 200mL three-necked flask, remove water and oxygen, add polymethacrylic acid (10g, 0.0038mol) (Mw=2600), and then add 50mL chloroform, stir until completely dissolved, and obtain mixed solution H. Take N,N'-dicyclohexylcarbodiimide (DCC) (0.034mol, 7.0g) and fully dissolve it in 5mL chloroform to obtain mixed solution Q. Then heat the mixed solution H to 65℃, and then very slowly drop it into the mixed solution Q. Keep at 65℃ and fully react for 10 hours. After the reaction is completed, it is recorded as product A and wait for the next reaction.

[0091] Hydroxyl esterification reaction: Undecanol (0.034 mol, 5.85 g) was dissolved in 50 mL of chloroform to obtain a mixed solution W. Product A was transferred to a 250 mL reaction bottle, heated to 65 °C and slowly added dropwise, and the mixed solution W was slowly added dropwise. After the addition was completed, the temperature was maintained at 65 °C for esterification. After 48 hours of reaction, the mixture was taken out, most of the chloroform was evaporated, and then the product was precipitated with a large amount of petroleum ether, the supernatant layer was sucked out, the product layer was separated, the product layer was re-dissolved with chloroform, and then the solvent was evaporated to obtain product B.

[0092] Product B was dissolved in 100 mL of water, and NaOH was slowly added at room temperature to adjust the pH value to 10. After the reaction was completed, the product was dried to obtain modified polymethacrylate sodium salt, which was recorded as product 3.

[0093] Product 3 includes structural unit A and structural unit B Among them, the quantity ratio of structural unit A to structural unit B is 4.2:10.

[0094] Synthesis example 4

[0095] Carboxyl activation reaction: Take a 200mL three-necked flask, remove water and oxygen, add polyacrylic acid (10g, 0.005mol) (Mw=2000), and then add 50mL chloroform, stir until completely dissolved, and obtain mixed solution H. Take N,N'-dicyclohexylcarbodiimide (DCC) (0.0345mol, 7.1g) and fully dissolve it in 50mL chloroform to obtain mixed solution Q. Heat the mixed solution H to 70℃, then drip the mixed solution Q very slowly, keep 70℃ for carboxyl activation, and fully react for 15h. After the reaction is completed, it is recorded as product A and wait for the next reaction.

[0096] Hydroxyl esterification reaction: n-hexanol (0.0345 mol, 3.52 g) was dissolved in 50 mL of chloroform to obtain a mixed solution W. Product A was transferred to a 250 mL reaction bottle, heated to 70°C, and the mixed solution W was slowly added dropwise. After the addition was completed, the temperature was maintained at 70°C for esterification. After 22 hours of reaction, the mixture was taken out, most of the chloroform was evaporated, and then the product was precipitated with a large amount of petroleum ether, the supernatant layer was sucked out, the product layer was separated, the product layer was redissolved with chloroform, and then the solvent was evaporated to obtain product B.

[0097] Product B was dissolved in 100 mL of water, and NaOH was slowly added at room temperature to adjust the pH value to 9. After the reaction was completed, the product was dried to obtain modified polyacrylic acid sodium salt, which was recorded as product 4.

[0098] Product 4 includes structural unit A and structural unit B The ratio of the number of structural unit A to that of structural unit B is 1:3.

[0099] Synthesis example 5

[0100] Carboxyl activation reaction: Take a 200mL three-necked flask, remove water and oxygen, add polymaleic acid (10g, 0.004mol) (Mw=2500), and then add 50mL chloroform, stir until completely dissolved, and obtain mixed solution H. Take N,N'-dicyclohexylcarbodiimide (DCC) (0.043mol, 8.9g) and fully dissolve it in 50mL chloroform to obtain mixed solution Q. Then heat the mixed solution H to 75℃, and then very slowly drop it into the mixed solution Q. Keep the carboxyl activation at 75℃, and fully react for 48h. After the reaction is completed, it is recorded as product A and wait for the next reaction.

[0101] Hydroxyl esterification reaction: Dissolve n-pentadecanol (0.043 mol, 9.8 g) in 50 mL of chloroform to obtain a mixed solution W. Transfer product A to a 250 mL reaction bottle, heat to 75 °C and slowly dropwise add the mixed solution W. After the addition is complete, maintain 75 °C for esterification. After 10 hours of reaction, take out, evaporate most of the chloroform, and then precipitate the product with a large amount of petroleum ether, suck out the supernatant layer, separate the product layer, dissolve the product layer again with chloroform, and then evaporate the solvent to obtain product B.

[0102] Product B was dissolved in 100 mL of water, and KOH was slowly added at room temperature to adjust the pH value to 9. After the reaction was completed, the product was dried to obtain the modified polymaleic acid sodium salt, which was recorded as product 5.

[0103] Product 5 includes structural unit A and structural unit B Among them, the quantity ratio of structural unit A to structural unit B is 3.3:10.

[0104] Synthesis example 6

[0105] Carboxyl activation reaction: Take a 200mL three-necked flask, remove water and oxygen, add polymethacrylic acid (10g, 0.0038mol) (Mw=2600), and then add 50mL chloroform, stir until completely dissolved, and obtain mixed solution H. Take N,N'-dicyclohexylcarbodiimide (DCC) (0.034mol, 7.0g) and fully dissolve it in 5mL chloroform to obtain mixed solution Q. Then heat the mixed solution H to 65℃, and then very slowly drop it into the mixed solution Q. Keep at 65℃ and fully react for 10 hours. After the reaction is completed, it is recorded as product A and wait for the next reaction.

[0106] Hydroxyl esterification reaction: n-eicosanol (0.034 mol, 10.2 g) was dissolved in 50 mL of chloroform to obtain a mixed solution W. Product A was transferred to a 250 mL reaction bottle, heated to 65°C and slowly added dropwise, and the mixed solution W was slowly added dropwise. After the addition was completed, the temperature was maintained at 65°C for esterification. After 48 hours of reaction, the mixture was taken out, most of the chloroform was evaporated, and then the product was precipitated with a large amount of petroleum ether, the supernatant layer was sucked out, the product layer was separated, the product layer was re-dissolved with chloroform, and then the solvent was evaporated to obtain product B.

[0107] Product B was dissolved in 100 mL of water, and NaOH was slowly added at room temperature to adjust the pH value to 10. After the reaction was completed, the product was dried to obtain modified polymethacrylate sodium salt, which was recorded as product 6.

[0108] Product 6 includes structural unit A and structural unit B Among them, the quantity ratio of structural unit A to structural unit B is 4.2:10.

[0109] Synthesis Example 7

[0110] The only difference from Synthesis Example 1 is that in the hydroxy esterification reaction, phenylpentyl alcohol (0.04 mol, 6.57 g) is dissolved in chloroform to obtain a mixed solution W. The synthesized product is recorded as Product 7.

[0111] In product 7, structural unit A and structural unit B The quantity ratio is 4:10.

[0112] Synthesis example 8

[0113] The only difference from Synthesis Example 1 is that n-pentanol (0.04 mol, 3.5 g) is dissolved in chloroform in the hydroxy esterification reaction to obtain a mixed solution W. The synthesized product is recorded as Product 8.

[0114] In product 8, structural unit A and structural unit B The quantity ratio is 4:10.

[0115] Synthesis example 9

[0116] The only difference from Synthesis Example 1 is that in the hydroxy esterification reaction, n-trisinol (0.04 mol, 13.6 g) is dissolved in chloroform to obtain a mixed solution W. The synthesized product is recorded as Product 9.

[0117] In product 9, structural unit A and structural unit B The quantity ratio is 4:10.

[0118] Example 1

[0119] Silicon wafer water-based cutting fluid, wherein the water-based cutting fluid has the following component contents by mass percentage:

[0120] Propylene glycol 40%

[0121] Dispersant: Modified polyacrylic acid sodium salt (product 1) 5%

[0122] pH adjuster: Succinic acid 1%

[0123] Deionized water 54%

[0124] Preparation method: first add succinic acid, then add deionized water, stir to dissolve the succinic acid, add modified polyacrylic acid sodium salt (product 1), and finally add propylene glycol, stir for 2 hours until uniform, and the water-based cutting fluid of the present application is obtained.

[0125] Example 2

[0126] Silicon wafer water-based cutting fluid, wherein the water-based cutting fluid has the following component contents by mass percentage:

[0127] Ethylene glycol 15%

[0128] Dispersant: Modified polymaleic acid sodium salt (product 2) 10%

[0129] pH adjuster: citric acid 5%

[0130] Deionized water 70%

[0131] Preparation method: first add citric acid, then add deionized water, stir to dissolve the citric acid, add modified polymaleic acid sodium salt, and finally add ethylene glycol, stir for 2 hours until uniform, and the water-based cutting fluid of the present application is obtained.

[0132] Example 3

[0133] Silicon wafer water-based cutting fluid, wherein the water-based cutting fluid has the following component contents by mass percentage:

[0134] Ethylene glycol 10%

[0135] Dispersant: Modified polymethacrylate sodium salt (product 3) 8%

[0136] pH adjuster: 5M hydrochloric acid 2%

[0137] Deionized water 80%

[0138] Preparation method: first add deionized water, then add hydrochloric acid, then add modified polymethacrylate sodium salt, and finally add ethylene glycol, stir for 2 hours until uniform, and the water-based cutting fluid of the present application is obtained.

[0139] Example 4

[0140] Silicon wafer water-based cutting fluid, wherein the water-based cutting fluid has the following component contents by mass percentage:

[0141] Propylene glycol 40%

[0142] Dispersant: Modified polyacrylic acid sodium salt (product 4) 9%

[0143] pH adjuster: citric acid 1%

[0144] Deionized water 50%

[0145] Preparation method: first add citric acid, then add deionized water, stir to dissolve the citric acid, add modified polyacrylic acid sodium salt, and finally add propylene glycol, stir for 2 hours until uniform, and the water-based cutting fluid of the present application is obtained.

[0146] Example 5

[0147] Silicon wafer water-based cutting fluid, wherein the water-based cutting fluid has the following component contents by mass percentage:

[0148] Ethylene glycol 36%

[0149] Dispersant: Modified polymaleic acid sodium salt (product 5) 8%

[0150] pH adjuster: 1M sulfuric acid 2%

[0151] Deionized water 54%

[0152] Preparation method: first add deionized water, then add sulfuric acid, then add modified polymaleic acid sodium salt, and finally add ethylene glycol, stir for 2 hours until uniform, and then obtain the water-based cutting fluid of the present application.

[0153] Example 6

[0154] Silicon wafer water-based cutting fluid, wherein the water-based cutting fluid has the following component contents by mass percentage:

[0155] Propylene glycol 55%

[0156] Dispersant: Modified polymethacrylate sodium salt (product 6) 10%

[0157] pH adjuster: 2 M hydrochloric acid 1%

[0158] Deionized water 34%

[0159] Preparation method: first add deionized water, then add hydrochloric acid, then add modified polymethacrylate sodium salt, and finally add propylene glycol, stir for 2 hours until uniform, and the water-based cutting fluid of the present application is obtained.

[0160] Example 7

[0161] The only difference from Example 1 is that the dispersant used is Product 4, that is, the water-based cutting fluid of the present application is obtained.

[0162] Example 8

[0163] The only difference from Example 1 is that the dispersant used is Product 6, that is, the water-based cutting fluid of the present application is obtained.

[0164] Comparative Example 1

[0165] The only difference from Example 1 is that the dispersant used is Product 7, and the result is recorded as the comparative example water-based cutting fluid.

[0166] Comparative Example 2

[0167] The only difference from Example 1 is that the dispersant used is Product 8, and the result is recorded as the comparative example water-based cutting fluid.

[0168] Comparative Example 3

[0169] The only difference from Example 1 is that the dispersant used is Product 9, and the result is recorded as the comparative example water-based cutting fluid.

[0170] Performance and index testing

[0171] Test Method

[0172] The specific heat capacity, COD value and stability of the cutting fluids prepared in the above examples and comparative examples were measured.

[0173] Measurement of specific heat capacity:

[0174] The cooling performance of each cutting fluid was tested using a specific heat capacity tester. The results are shown in Table 1. The higher the specific heat capacity, the better the cooling performance.

[0175] Measurement of COD value:

[0176] The COD value of each cutting fluid was measured using a multi-parameter water quality analyzer GNST-900. The test results are shown in Table 1. The lower the COD value, the better the environmental performance.

[0177] Measurement of stability (shelf life):

[0178] The newly prepared cutting fluid is sealed and stored at room temperature. A certain amount of sample is taken every month to measure its pH, conductivity, viscosity, density and surface tension. If the value changes within ±5%, it means that it is still within the shelf life. The test results are shown in Table 1.

[0179] The cutting fluids prepared in the above examples and comparative examples were mixed with 1500# SiC powder at a ratio of 1:1 and stirred to prepare cutting mortar. The dispersibility, suspension performance and silicon wafer cleaning performance of the cutting mortar were tested under the same conditions.

[0180] Measurement of dispersion properties:

[0181] Laser particle size analyzer Malvern MS3000 was used to test the particle size of SiC particles in different cutting fluids to investigate its ability to disperse SiC. The test results are shown in Table 2. The smaller the particle size distribution range, the better the dispersion.

[0182] Measurement of suspension performance:

[0183] Take 250mL of the newly prepared mortar and pour it into a 250mL measuring cylinder. Let it stand under constant temperature and humidity conditions (25°C, air humidity 50%). Record the height of the mortar settlement after standing for 24 hours, and examine its respective suspension performance through the settlement height. The test results are shown in Table 2. The smaller the settlement height, the better the suspension performance.

[0184] Measurement of cleaning performance:

[0185] Take clean silicon wafers and soak them in the newly prepared mortar for 8 hours. After taking them out, rinse them with ultrapure water for 8 to 12 minutes, dry them at 100°C, and observe the surface cleanliness of the silicon wafers. The surface that is smooth and has no residue is considered to have "excellent" cleaning performance, and the surface that is unclean, has flower pieces, and dirty pieces is considered to have "difficult to clean" cleaning performance. The test results are shown in Table 2.

[0186] Measurement of cutting yield:

[0187] Cutting experiments were conducted with each cutting fluid to test the cutting yield rate. Cutting yield rate = number of silicon wafers with appearance grade that meet the specified requirements per cut / theoretical number of wafers per cut × 100%. Specific appearance grade requirements can be adjusted according to actual product needs of users.

[0188] This application was experimented based on thickness: 870μm±15μm, warpage: 0 to 14μm, and curvature: -3μm to 4.8μm.

[0189] Test Results

[0190] Table 1

[0191] serial number Specific heat capacity (KJ / Kg·℃) COD(mg / L) Shelf life (years) Example 1 2.3 81600 1.5 Example 2 2.5 81070 1.5 Example 3 2.5 81090 1.5 Example 4 2.4 82100 1.5 Example 5 2.6 82250 1.5 Example 6 2.4 82200 1.5 Example 7 2.3 82810 1.5 Example 8 2.5 82570 1.5 Comparative Example 1 1.4 92650 1 Comparative Example 2 1.7 91900 1 Comparative Example 3 2.0 90730 1

[0192] Table 2

[0193] serial number Particle size distribution range / μm Sedimentation height / mL Cleaning performance Cutting yield / % Example 1 2～13 30 excellent 98 Example 2 2～17 32 excellent 98 Example 3 2～18 31 excellent 97 Example 4 3～13 32 excellent 98 Example 5 2～16 32 excellent 97 Example 6 2～15 30 excellent 97 Example 7 5～13 31 excellent 94 Example 8 10～20 37 excellent 96 Comparative Example 1 19～45 56 Difficult to clean 85 Comparative Example 2 12～30 50 Difficult to clean 70 Comparative Example 3 20～51 53 Difficult to clean 65

[0194] As can be seen from Table 1, the specific heat capacity and shelf life of the water-based cutting fluid prepared in the embodiment are higher than those of the comparative cutting fluid, indicating that the water-based cutting fluid of the embodiment has excellent cooling performance, stable properties, and long shelf life. At the same time, the COD of the water-based cutting fluid prepared in the embodiment is significantly lower than that of the comparative cutting fluid, indicating that the water-based cutting fluid of the present application is more environmentally friendly and can reduce environmental pollution when the cutting fluid is used.

[0195] As can be seen from Table 2, the particle size distribution range and sedimentation height of the water-based cutting fluid prepared in the embodiment are lower than those of the comparative cutting fluid, indicating that the water-based cutting fluid of the present application has strong dispersibility and suspension. At the same time, the cutting yield rate of the embodiment is also higher than that of the comparative cutting fluid, indicating that the water-based cutting fluid of the present application is not only easy to clean, but also can improve the cutting yield rate.

[0196] The preferred embodiments of the present invention are described in detail above. However, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A water-based cutting fluid, which is composed of a modified polycarboxylate, a pH regulator, a polyol and water, wherein the modified polycarboxylate comprises a structural unit A and a structural unit B, and the structural formulas of the structural unit A and the structural unit B are as follows: in, R2 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms, -COOR1 or -COOM; Each R1 is the same or different and is independently selected from an alkyl group having 6 to 20 carbon atoms; R3 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms or -COOM; M is selected from monovalent metal cations; The quantitative ratio of structural unit A to structural unit B is 2.5:10 to 9.5:10; The polyol is selected from one or more of ethylene glycol, propylene glycol and butylene glycol; Based on the mass of the water-based cutting fluid, the mass percentage of the modified polycarboxylate is 1% to 15%; the mass percentage of the pH regulator is 0.5% to 10%; the mass percentage of the polyol is 5% to 60%; and the mass percentage of water is 20% to 80%.

2. The water-based cutting fluid according to claim 1, characterized in that: Each R1 is the same or different and is independently selected from an alkyl group having 8 to 15 carbon atoms; and / or R2 is selected from hydrogen, methyl, ethyl, -COOR1 or -COOM; and / or R3 is selected from hydrogen, methyl, ethyl or -COOM; and / or M is selected from Na + or K + .

3. The water-based cutting fluid according to claim 1, characterized in that: Each R1 is the same or different and is independently selected from n-octyl, isooctyl, n-heptyl, n-undecyl, isomeric dodecyl, isomeric tridecyl, and n-pentadecyl.

4. The water-based cutting fluid according to claim 1, characterized in that: The quantitative ratio of the structural unit A to the structural unit B is 3:10 to 5:

10.

5. The water-based cutting fluid according to claim 1, characterized in that: The weight average molecular weight of the modified polycarboxylate is 1500-6500.

6. The water-based cutting fluid according to claim 1, characterized in that: The weight average molecular weight of the modified polycarboxylate is 2000-4500.

7. The water-based cutting fluid according to claim 1, characterized in that: The preparation method of the modified polycarboxylate comprises the following steps: Carrying out a partial carboxyl activation reaction on the polycarboxylic acid to obtain a partially carboxyl activated polycarboxylic acid; The partially carboxyl-activated polycarboxylic acid is subjected to an esterification reaction with an alcohol substance to obtain an esterification product; reacting the remaining carboxyl groups in the esterification product with a metal oxide or a metal hydroxide to obtain the modified polycarboxylate; The structural unit contained in the polycarboxylic acid is shown in Formula I, and the structural formula of the alcohol substance is shown in Formula II: R4 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms or -COOH; R1 has the same definition as in claim 1.

8. The water-based cutting fluid according to claim 1, characterized in that: Based on the mass of the water-based cutting fluid, the mass percentage of the modified polycarboxylate is 5% to 10%.

9. The water-based cutting fluid according to claim 1, characterized in that: The pH regulator is selected from one or more of hydrochloric acid, nitric acid, sulfuric acid, potassium sodium carbonate, citric acid and succinic acid; and / or Based on the mass of the water-based cutting fluid, the mass percentage of the pH regulator is 1% to 5%.

10. The water-based cutting fluid according to claim 1, characterized in that: The polyol is selected from one or both of ethylene glycol and propylene glycol; and / or Based on the mass of the water-based cutting fluid, the mass percentage of the polyol is 10% to 55%.

11. The water-based cutting fluid according to claim 1, characterized in that: Based on the mass of the water-based cutting fluid, the mass percentage of water is 34% to 80%.

12. Use of the water-based cutting fluid according to any one of claims 1 to 11 in cutting semiconductor silicon wafers.

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