Easily-dispersed diamond grinding fluid and preparation method thereof

Abstract

The invention discloses easy-to-disperse diamond grinding fluid and a preparation method thereof, and relates to the technical field of grinding fluid. The easy-to-disperse diamond grinding fluid is prepared from the following raw materials in parts by weight: 1 to 20 parts of modified diamond micro powder, 40 to 80 parts of deionized water, 1 to 10 parts of polyethylene glycol 6000, 0.5 to 1.2 parts of sodium carboxymethyl cellulose, 1 to 20 parts of glycerol, 1 to 10 parts of triethanolamine, 0.3 to 0.7 part of sodium polyacrylate, 0.05 to 5 parts of 1, 2-benzisothiazolin-3-ketone and 1 to 10 parts of a modified silane coupling agent. According to the easy-to-disperse diamond grinding fluid, through the synergistic effect of the modified diamond micro powder and the modified silane coupling agent, the dispersity is excellent, and the stability is high; the formula is scientific, polyethylene glycol and other assistants are matched, precise process parameters and graded filtration are combined, the grinding efficiency is high, the surface smoothness of a workpiece is good, the antibacterial property and storage stability are good, and the application scene is wide.

Description

Technical Field

[0001] This invention relates to the field of polishing fluid technology, specifically to an easily dispersible diamond polishing fluid and its preparation method. Background Technology

[0002] Diamond polishing slurry, a core material in precision wafer grinding and processing fields such as semiconductors and sapphire, plays an irreplaceable role in high-end industries such as electronic component manufacturing and optical device processing due to its dispersion stability directly determining the surface finish and cutting efficiency of the workpiece. With technological advancements, the requirements for surface smoothness and flatness in wafer processing are becoming increasingly stringent, highlighting the technical shortcomings of traditional diamond polishing slurries.

[0003] In existing technologies, diamond polishing slurries are mostly prepared by directly mixing and stirring the slurry with diamond micropowder. Because diamond micropowder has a uniform particle size and small particle diameter (typically D50 = 1-10 μm), its surface is strongly hydrophobic, making it difficult to achieve uniform dispersion in aqueous polishing slurry systems. Conventional stirring processes lack sufficient shear force to overcome the van der Waals forces and hydrophobic interactions between the micropowder particles, leading to a high tendency for the diamond micropowder to agglomerate and form large aggregates.

[0004] These agglomerates can cause deep scratches on the wafer surface during grinding, severely affecting processing accuracy and product yield. Simultaneously, agglomeration reduces the effective cutting area of ​​diamond micropowder, leading to decreased grinding efficiency and increased processing costs. Furthermore, traditional grinding slurries lack targeted modification of the diamond micropowder's surface properties, resulting in poor suspension stability in aqueous systems and a tendency for sedimentation and stratification, further exacerbating the instability of the processing and failing to meet the technical requirements of high-end wafer precision machining.

[0005] Therefore, developing a new type of polishing slurry that can effectively improve the dispersibility and suspension stability of diamond micropowder and avoid scratches during wafer processing has become a key issue that urgently needs to be addressed in the field of polishing slurry technology, and is of great significance to promoting the upgrading and development of the precision machining industry. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an easily dispersible diamond polishing slurry and its preparation method, solving the problems of agglomeration, poor dispersibility, and insufficient suspension stability of existing diamond micropowders.

[0007] To achieve the above objectives, the present invention provides the following technical solution: An easily dispersible diamond polishing slurry comprises the following raw materials in parts by weight: 1-20 parts modified diamond micro powder, 40-80 parts deionized water, 1-10 parts polyethylene glycol 6000, 0.5-1.2 parts sodium carboxymethyl cellulose, 1-20 parts glycerol, 1-10 parts triethanolamine, 0.3-0.7 parts sodium polyacrylate, 0.05-5 parts 1,2-benzisothiazolin-3-one, and 1-10 parts modified silane coupling agent.

[0008] Furthermore, the modified diamond micro powder is prepared using the following specific steps: A1. First, add diamond micro powder to an ethanol-water mixture with a volume ratio of 3:1, stir to disperse and form a suspension, heat to 50-60℃, slowly add silane coupling agent KH-550, and stir at a constant temperature of 200-250 r / min for 2-3 h; continue to add maleic anhydride, heat to 70-80℃, and react for 4-5 h; after the reaction is completed, wash with deionized water by centrifugation at 4000 r / min 3-4 times, 10-15 min each time, and vacuum dry the product at 80-90℃ for 4-6 h to obtain the first modified diamond micro powder; By grafting with silane coupling agent KH-550 and modifying with maleic anhydride, carboxyl / amide hydrophilic groups are introduced onto the surface of diamond micropowder, which initially improves hydrophobicity and reduces the agglomeration force between micropowders, laying the foundation for further modification. At the same time, impurities are removed to avoid secondary pollution.

[0009] A2. Take the first modified diamond micro powder, disperse it in deionized water, and ultrasonically disperse it at 300W for 30-40 min to form a uniform suspension. Adjust the pH to 9-10 with concentrated ammonia. Slowly add a 25% (w / w) tetraethyl orthosilicate toluene solution and stir at 150-200 r / min for 1-2 h at 40-50℃. Add epichlorohydrin to the system, heat to 60-70℃, and stir for 3-4 h. Then add nano-alumina with a particle size of 20-50 nm and continue stirring for 2-3 h. Wash with a 0.5% (w / w) citric acid solution at 40℃ for 30 min, then centrifuge, wash with deionized water until neutral, and vacuum dry at 60-70℃ for 5-7 h to obtain the second modified diamond micro powder. Through silane hydrolysis coating, introduction of epichlorohydrin active groups, and nano-alumina composite modification, the surface activity and mechanical properties of the micro powder are further optimized, its dispersion stability in aqueous systems is enhanced, and its wear resistance is improved, thus ensuring efficient grinding.

[0010] A3. Add the second modified diamond micro powder to N,N-dimethylformamide, ultrasonically disperse at 300W for 20-30 min, add 2-acrylamido-2-methylpropanesulfonic acid, purge with nitrogen at a flow rate of 45 sccm for protection, heat to 65-75℃, add ammonium persulfate, and react at 200-250 r / min for 3-4 h; continue to add dimethylaminoethyl methacrylate to the system, and continue to react for 2-3 h; after the reaction is completed, wash 2-3 times with a 1:2 volume ratio ethanol-deionized water mixed solution, centrifuge at 4000 r / min for 15-20 min, and vacuum dry the product at 70-80℃ for 6-8 h to obtain modified diamond micro powder.

[0011] By grafting hydrophilic polymer chains onto the surface of micropowder through monomer polymerization, the compatibility and affinity between micropowder and aqueous grinding fluid system are significantly enhanced, completely solving the dispersion problem. At the same time, the surface charge stability of micropowder is improved, further inhibiting agglomeration and sedimentation.

[0012] Furthermore, the diamond micro powder has a particle size of 0.5-10μm to avoid the problems of large particles scratching the workpiece and small particles not cutting enough; the D50 particle size is controlled within the range of 1-3μm to ensure a balance between cutting efficiency and surface finish during the grinding process.

[0013] Furthermore, the ratio of diamond micro powder, ethanol-water mixed solution, silane coupling agent KH-550, and maleic anhydride in A1 is 100g: 300-400mL: 20-30mL: 15-25g.

[0014] Furthermore, the ratio of the first modified diamond micro powder, deionized water, tetraethyl orthosilicate toluene solution, epichlorohydrin, and nano-alumina in A2 is 100g: 250-350mL: 10-15mL: 8-12g: 5-10g.

[0015] Furthermore, the ratio of the second modified diamond micro powder, N,N-dimethylformamide, 2-acrylamide-2-methylpropanesulfonic acid, ammonium persulfate, and dimethylaminoethyl methacrylate in A3 is 100g: 200-300mL: 12-18g: 0.5-1.0g: 8-15g.

[0016] Furthermore, the modified silane coupling agent is prepared using the following specific steps: B1. Take silane coupling agents KH-550 and KH-560, add them to toluene, stir to dissolve, and heat to 60-70℃; slowly add hydroxyethyl acrylate, add azobisisobutyronitrile, purge with nitrogen for protection, and react at 200-250 r / min for 4-5 h; then add adipic acid dihydrazide, heat to 80-90℃, and stir to react for 3-4 h; after the reaction is completed, remove toluene by vacuum distillation at -0.095 MPa and 60℃ to obtain the first modified silane coupling agent; By copolymerizing two silane coupling agents and crosslinking them with adipic acid dihydrazide, multi-functional active groups are introduced to enhance the bonding ability between the coupling agents and the surface of diamond micropowder, laying the foundation for subsequent compatibility and synergistic dispersion with aqueous systems.

[0017] B2. Dissolve the first modified silane coupling agent in dichloromethane, cool to 0-5℃, slowly add epichlorohydrin, and stir the reaction at 150-200 r / min for 2-3 h; then raise the temperature to 25-35℃, add diethylenetriamine, and continue stirring the reaction for 4-6 h. Adjust the pH of the system to 6-7 with hydrochloric acid, allow it to stand and separate into layers, take the organic phase, wash it 2-3 times with deionized water, and remove the dichloromethane by vacuum distillation at -0.095 MPa and 50℃ to obtain the second modified silane coupling agent. By epoxidation with epichlorohydrin and amination with diethylenetriamine, hydrophilic amine groups are introduced into the coupling agent molecule, which improves its solubility and dispersibility in aqueous systems, and enhances its coordination with functional groups on the surface of diamond micropowder.

[0018] B3. Dissolve the second modified silane coupling agent in deionized water, add 3.2% sodium hydroxide solution to adjust the pH to 9-10, cool in a water bath to 5-10℃, and stir at 200 rpm. Slowly add anhydrous sodium sulfite in 5 batches, adding the next batch only after no more bubbles are generated in the system. After all the additions are complete, continue stirring the reaction, maintaining the temperature ≤15℃. Sodium sulfite reacts with the epoxy groups contained in the second modified silane coupling agent to form a sodium hydroxysulfonate structure after ring opening. As the pH gradually decreases, excess Na2SO3 / NaHSO3 at pH <7... SO2 is released during the reaction. SO2 dissolves in water to form sulfurous acid. The reaction ends when the pH of the system stabilizes at 3-4 and no irritating gas is released. The system is allowed to stand for 30 minutes. The clear supernatant is taken, ammonium dihydrogen phosphate is added, and sodium hydroxide solution is added dropwise to adjust the pH to 6.5-7.0. The mixture is stirred at 200-250 rpm and heated to 70°C in a water bath. The mixture is kept at this temperature and stirred for 3-4 hours. The mixture is then cooled to room temperature, filtered, and the filter cake is washed 2-3 times with deionized water. The filter cake is then transferred to a vacuum drying oven and dried at 60-70°C for 5-7 hours to obtain the modified silane coupling agent.

[0019] By modifying the coupling agent with anhydrous sodium sulfite and ammonium dihydrogen phosphate, the hydrophilicity and dispersing activity of the coupling agent are further optimized, enabling it to form a highly efficient synergistic effect with the modified diamond micropowder, significantly reducing the risk of micropowder agglomeration and improving the overall dispersion stability of the grinding slurry.

[0020] Furthermore, the ratio of silane coupling agent KH-550, silane coupling agent KH-560, toluene, hydroxyethyl acrylate, azobisisobutyronitrile, and adipate dihydrazide in B1 is 25g:25g:100-150mL:10-15mL:0.3-0.6g:8-12g.

[0021] Furthermore, the ratio of the first modified silane coupling agent, dichloromethane, epichlorohydrin, and diethylenetriamine in B2 is 50g:80-120mL:12-18mL:6-10g.

[0022] Furthermore, the ratio of the second modified silane coupling agent, deionized water, anhydrous sodium sulfite, and ammonium dihydrogen phosphate in B3 is 50g:60-80mL:15-20g:8-12g.

[0023] A method for preparing an easily dispersible diamond polishing slurry, specifically comprising the following steps: S1. Add 40-80 parts of deionized water to the reactor. Slowly add 1-10 parts of polyethylene glycol 6000 while stirring at 300-500 r / min. Heat to 40-50℃ and stir for 30-40 min until completely dissolved. Add 0.5-1.2 parts of sodium carboxymethyl cellulose and 0.3-0.7 parts of sodium polyacrylate to the system. Heat to 60-70℃ and increase the stirring speed to 600-800 r / min. Stir for 1-1.5 h to form a uniform pre-dispersed base liquid. The viscosity of the base liquid is measured to be 200-500 mPa·s. Through gradient heating and variable speed stirring, polyethylene glycol 6000, sodium carboxymethyl cellulose, and sodium polyacrylate are fully dissolved and form a stable network structure. The viscosity of the base liquid is adjusted to a suitable range to provide a stable carrier for the uniform dispersion of modified diamond micropowder and avoid initial agglomeration.

[0024] S2. Slowly add 1-20 parts of modified diamond micropowder to the pre-dispersed base liquid, while simultaneously ultrasonically dispersing at 400W, maintaining a stirring speed of 800-1000 r / min, and controlling the temperature at 50-60℃, for 1.5-2 hours; add 1-10 parts of modified silane coupling agent, continue ultrasonic dispersion, increase the stirring speed to 1200-1500 r / min, raise the temperature to 70-80℃, and react for 2-2.5 hours; the synergistic effect of ultrasonic dispersion and high-speed stirring, combined with the heating operation, promotes the full interaction between modified diamond micropowder and modified silane coupling agent, breaks down residual agglomerates, forms a stable dispersion system, and enhances the synergistic dispersion effect of the two.

[0025] S3. After completion, turn off the ultrasonicator, reduce the stirring speed to 600-800 r / min, and the temperature to 40-50℃. Slowly add 1-20 parts of glycerol to the system and stir for 30-40 min. Add 1-10 parts of triethanolamine dropwise to adjust the pH of the system to 8.0-8.5 and stir for 20-30 min, continuously monitoring the pH to ensure it remains stable within the target range. Then add 0.05-5 parts of 1,2-benzisothiazolin-3-one and stir for 30-40 min to ensure the antibacterial agent is evenly dispersed in the system. Reduce the stirring speed and temperature to avoid system fluctuations. By precisely adjusting the pH and ensuring even dispersion of components, the system maintains long-term stability, reduces micronized powder sedimentation, and imparts antibacterial properties to the grinding slurry, preventing deterioration during storage.

[0026] S4. Replace the stirring device in the reactor with a shear dispersion disc, and perform high-intensity shear dispersion at 2000-3000 r / min for 3-4 hours at 30-40℃. After shear dispersion, cool the system to room temperature and perform primary filtration with a 2000-3000 mesh filter screen, followed by secondary filtration using a plate and frame filter press with a filtration accuracy of 1-2 μm and a pressure of 0.3-0.5 MPa. High-intensity shear dispersion further refines the dispersion system, and graded filtration accurately removes large particulate impurities and residual agglomerates, ensuring that the grinding fluid does not scratch the workpiece and improving the surface finish of the processed surface.

[0027] S5. Transfer the filtered grinding slurry to the finished product tank and let it stand at room temperature for 24-48 hours for maturation. During this process, stir at 300-500 rpm for 30 minutes every 6 hours. After maturation, fill and seal to obtain the easily dispersible diamond grinding slurry. The combination of room temperature maturation and intermittent stirring ensures that the components are fully compatible and blended, improving the storage stability and consistency of the grinding slurry, and ensuring uniform dispersion and stable performance during subsequent use.

[0028] Furthermore, in S2, the ultrasonic dispersion is performed intermittently, that is, after 30 minutes of ultrasonic operation, it is paused for 10 minutes, and the cycle is repeated until the end, while the distance between the ultrasonic probe and the liquid surface is controlled to be 2-3 cm.

[0029] This invention provides an easily dispersible diamond polishing slurry and its preparation method, which has the following beneficial effects: 1. This invention employs a three-stage modification process to surface-treat diamond micropowder, successfully transforming its hydrophobic functional groups into hydrophilic functional groups, significantly enhancing the affinity between the micropowder and the aqueous polishing slurry system. Simultaneously, a specially formulated modified silane coupling agent further reduces the agglomeration forces between micropowder particles. Combined with pre-dispersed base liquid viscosity control, intermittent ultrasonic dispersion, and the high-intensity shearing action of the shear dispersion disc, multiple dispersion safeguards are formed, effectively preventing the agglomeration and sedimentation of diamond micropowder in the aqueous system. The polishing slurry maintains a uniform and stable dispersion even after prolonged standing, requiring no additional stirring before direct use, significantly improving the stability and convenience of the processing.

[0030] 2. Because diamond micron powder achieves uniform dispersion, it avoids the formation of agglomerates. During the grinding and processing of silicon carbide, sapphire, and other wafers, the micron powder can fully exert its cutting action, and the cutting force is evenly distributed, effectively preventing processing defects caused by agglomerates scratching the wafer surface. Simultaneously, the particle size and distribution of the diamond micron powder are precisely controlled, combined with modified and optimized surface properties, ensuring both efficient cutting and reduced damage to the workpiece surface during grinding. This significantly improves the smoothness and flatness of the wafer surface, substantially reducing the product defect rate and meeting the stringent surface quality requirements of high-end precision machining.

[0031] 3. This invention optimizes the formulation and preparation process, ensuring high suspension and uniform dispersion of diamond micropowder in the grinding fluid. This maximizes the cutting performance of each micropowder particle, avoiding the reduction in effective cutting area caused by agglomeration, and significantly improving grinding efficiency compared to traditional grinding fluids. Furthermore, the addition of polyethylene glycol 6000, glycerin, and other components in the formulation forms a good lubrication and protection system, reducing wear and loss of the diamond micropowder and extending the service life of the grinding fluid. Simultaneously, the modified micropowder exhibits better compatibility with the components of the grinding fluid, resulting in strong system stability and allowing for long-term cyclic use without performance degradation, thus reducing processing costs.

[0032] 4. The polishing slurry formula of this invention is scientifically sound and reasonable. By precisely controlling key parameters such as pH value and viscosity, and combining it with the addition of antibacterial agents, it not only adapts to the polishing needs of wafers made of different materials such as semiconductors and sapphire, but also effectively inhibits bacterial growth during storage and use, avoiding problems such as deterioration and off-odors caused by bacterial proliferation, thus extending the shelf life. Furthermore, all raw materials in the polishing slurry are selected from environmentally friendly and safe components, containing no harmful volatile substances, and no irritating gases are generated during processing, making it friendly to operators and the environment. Its stable performance allows it to maintain excellent performance under different processing equipment and process conditions, making it suitable for a wide range of applications. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1: Preparation of easily dispersible diamond polishing slurry. The specific preparation steps are as follows: S1. Take 40 parts of deionized water and add it to the reactor. Slowly add 1 part of polyethylene glycol 6000 while stirring at 300 r / min. Heat to 40℃ and stir for 30 min until completely dissolved. Add 0.5 parts of sodium carboxymethyl cellulose and 0.3 parts of sodium polyacrylate to the system. Heat to 60℃ and increase the stirring speed to 600 r / min. Stir for 1 h to form a uniform pre-dispersed base liquid. The viscosity of the base liquid is measured to be 200-500 mPa·s. S2. Slowly add 1 part of modified diamond micro powder to the pre-dispersed base liquid, and simultaneously perform intermittent ultrasonic dispersion at 400W power for 30 minutes followed by a 10-minute pause, maintaining a stirring speed of 800 r / min and a temperature of 50℃ for 1.5 hours; add 1 part of modified silane coupling agent, continue intermittent ultrasonic dispersion, increase the stirring speed to 1200 r / min, raise the temperature to 70℃, and react for 2 hours; S3. After completion, turn off the ultrasound, reduce the stirring speed to 600 r / min and the temperature to 40℃. Slowly add 1 part of glycerol to the system and stir for 30 min. Add 1 part of triethanolamine dropwise to adjust the pH of the system to 8.0 and stir for 20 min, continuously monitoring the pH value to ensure it remains stable within the target range. Then add 0.05 parts of 1,2-benzisothiazolin-3-one and stir for 30 min to ensure the antibacterial agent is evenly dispersed in the system. S4. Replace the stirring device in the reactor with a shear dispersion disc and perform high-intensity shear dispersion at 2000 r / min for 3 h at 30℃. After shear dispersion, cool the system to room temperature, perform primary filtration with a 2000 mesh filter, and then perform secondary filtration with a plate and frame filter press with a filtration accuracy of 1 μm and a pressure of 0.3 MPa. S5. Transfer the filtered grinding slurry into the finished product tank and let it stand at room temperature for 24 hours for maturation treatment. During this period, stir at 300 r / min for 30 minutes every 6 hours. After maturation, fill and seal to obtain the finished product of easily dispersible diamond grinding slurry.

[0035] Example 2: Preparation of easily dispersible diamond polishing slurry. The specific preparation steps are as follows: S1. Add 80 parts of deionized water to the reactor, slowly add 10 parts of polyethylene glycol 6000 while stirring at 500 r / min, heat to 50℃, and stir for 40 min until completely dissolved; add 1.2 parts of sodium carboxymethyl cellulose and 0.7 parts of sodium polyacrylate to the system, heat to 70℃, increase the stirring speed to 800 r / min, and stir for 1.5 h to form a uniform pre-dispersed base liquid. The viscosity of the base liquid is measured to be 200-500 mPa·s. S2. Slowly add 20 parts of modified diamond micro powder to the pre-dispersed base liquid, and simultaneously perform intermittent ultrasonic dispersion at 400W power for 30 minutes followed by a 10-minute pause, maintaining a stirring speed of 1000 r / min and a temperature of 60℃ for 2 hours; add 10 parts of modified silane coupling agent, continue intermittent ultrasonic dispersion, increase the stirring speed to 1500 r / min, raise the temperature to 80℃, and react for 2.5 hours; S3. After completion, turn off the ultrasound, reduce the stirring speed to 800 r / min and the temperature to 50℃, slowly add 20 parts of glycerol to the system and stir for 40 min; add 10 parts of triethanolamine dropwise to adjust the pH of the system to 8.5 and stir for 30 min, continuously monitoring the pH value to ensure it remains stable within the target range; then add 5 parts of 1,2-benzisothiazolin-3-one and stir for 40 min to ensure the antibacterial agent is evenly dispersed in the system. S4. Replace the stirring device in the reactor with a shear dispersion disc and perform high-intensity shear dispersion at 3000 r / min for 4 h at 40℃. After shear dispersion, cool the system to room temperature, perform primary filtration with a 3000 mesh filter, and then perform secondary filtration with a plate and frame filter press with a filtration accuracy of 2 μm and a pressure of 0.5 MPa. S5. Transfer the filtered grinding slurry into the finished product tank and let it stand at room temperature for 48 hours for maturation treatment. During this period, stir at 500 r / min for 30 minutes every 6 hours. After maturation, fill and seal to obtain the finished product of easily dispersible diamond grinding slurry.

[0036] Example 3: Preparation of easily dispersible diamond polishing slurry. The specific preparation steps are as follows: S1. Add 60 parts of deionized water to the reactor, slowly add 5 parts of polyethylene glycol 6000 while stirring at 400 r / min, heat to 45℃, and stir for 35 min until completely dissolved; add 0.8 parts of sodium carboxymethyl cellulose and 0.5 parts of sodium polyacrylate to the system, heat to 65℃, increase the stirring speed to 700 r / min, and stir for 1.2 h to form a uniform pre-dispersed base liquid. The viscosity of the base liquid is measured to be 200-500 mPa·s. S2. Slowly add 10 parts of modified diamond micro powder to the pre-dispersed base liquid, and simultaneously perform intermittent ultrasonic dispersion at 400W power for 30 minutes followed by a 10-minute pause, maintaining a stirring speed of 900 r / min and a temperature of 55℃ for 1.8 h; add 5 parts of modified silane coupling agent, continue intermittent ultrasonic dispersion, increase the stirring speed to 1350 r / min, raise the temperature to 75℃, and react for 2.2 h; S3. After completion, turn off the ultrasound, reduce the stirring speed to 700 r / min, and the temperature to 45℃. Slowly add 10 parts of glycerol to the system and stir for 35 min. Add 5 parts of triethanolamine dropwise to adjust the pH of the system to 8.2 and stir for 25 min, continuously monitoring the pH to ensure it remains stable within the target range. Then add 3 parts of 1,2-benzisothiazolin-3-one and stir for 35 min to ensure the antibacterial agent is evenly dispersed in the system. S4. Replace the stirring device in the reactor with a shear dispersion disc and perform high-intensity shear dispersion at 2500 r / min for 3.5 h at 35℃. After shear dispersion, cool the system to room temperature, perform primary filtration with a 2500 mesh filter, and then perform secondary filtration with a plate and frame filter press with a filtration accuracy of 1 μm and a pressure of 0.4 MPa. S5. Transfer the filtered grinding slurry into the finished product tank and let it stand at room temperature for 36 hours for maturation treatment. During this period, stir at 400 r / min for 30 minutes every 6 hours. After maturation, fill and seal to obtain the finished product of easily dispersible diamond grinding slurry.

[0037] Example 4: Preparation of modified diamond micro powder. The specific preparation steps are as follows: A1. First, add 100g of diamond micro powder to 300mL of ethanol-water mixed solution with a volume ratio of 3:1, stir to disperse and form a suspension, heat to 50℃, slowly add 20mL of silane coupling agent KH-550, and stir at 200r / min for 2h; then add 15g of maleic anhydride, heat to 70℃, and react for 4h; after the reaction is completed, wash with deionized water by centrifugation at 4000r / min 3 times, 10min each time, and vacuum dry the product at 80℃ for 4h to obtain the first modified diamond micro powder; A2. Take 100g of the first modified diamond micro powder, disperse it in 250mL of deionized water, and ultrasonically disperse it at 300W for 30min to form a uniform suspension. Adjust the pH to 9 with concentrated ammonia. Slowly add 10mL of 25% tetraethyl orthosilicate toluene solution, stir at 150r / min for 1h at 40℃, add 8g of epichlorohydrin to the system, heat to 60℃, and stir for 3h. Then add 5g of 20nm nano-alumina, continue stirring for 2h, wash with 0.5% citric acid solution at 40℃ for 30min, then centrifuge, wash with deionized water until neutral, and vacuum dry at 60℃ for 5h to obtain the second modified diamond micro powder. A3. Add 100g of the second modified diamond micro powder to 200mL of N,N-dimethylformamide, sonicate at 300W for 20min, add 12g of 2-acrylamido-2-methylpropanesulfonic acid, purge with nitrogen at 45sccm for protection, heat to 65℃, add 0.5g of ammonium persulfate, and react at 200r / min for 3h; continue to add 8g of dimethylaminoethyl methacrylate to the system, and continue to react for 2h; after the reaction is completed, wash twice with a 1:2 volume ratio ethanol-deionized water mixture, centrifuge at 4000r / min for 15min, and dry the product under vacuum at 70℃ for 6h to obtain the modified diamond micro powder.

[0038] Example 5: Preparation of modified diamond micro powder. The specific preparation steps are as follows: A1. First, add 100g of diamond micro powder to 400mL of ethanol-water mixed solution with a volume ratio of 3:1, stir to disperse and form a suspension, heat to 60℃, slowly add 30mL of silane coupling agent KH-550, and stir at a constant temperature of 250r / min for 3h; then add 25g of maleic anhydride, heat to 80℃, and react for 5h; after the reaction is completed, wash with deionized water by centrifugation at 4000r / min 4 times, 15min each time, and dry the product under vacuum at 90℃ for 6h to obtain the first modified diamond micro powder; A2. Take 100g of the first modified diamond micro powder, disperse it in 350mL of deionized water, and ultrasonically disperse it at 300W for 40min to form a uniform suspension. Adjust the pH to 10 with concentrated ammonia. Slowly add 15mL of 25% tetraethyl orthosilicate toluene solution, stir at 200r / min for 2h at 50℃, add 12g of epichlorohydrin to the system, heat to 70℃, and stir for 4h. Then add 10g of 50nm nano-alumina, continue stirring for 3h, wash with 0.5% citric acid solution at 40℃ for 30min, then centrifuge, wash with deionized water until neutral, and vacuum dry at 70℃ for 7h to obtain the second modified diamond micro powder. A3. Add 100g of the second modified diamond micro powder to 300mL of N,N-dimethylformamide, and ultrasonically disperse at 300W for 30min. Add 18g of 2-acrylamido-2-methylpropanesulfonic acid, and purge with nitrogen at a flow rate of 45sccm for protection. Heat to 75℃, add 1.0g of ammonium persulfate, and react at 250r / min for 4h. Continue to add 15g of dimethylaminoethyl methacrylate to the system and continue to react for 3h. After the reaction is completed, wash three times with a 1:2 volume ratio ethanol-deionized water mixture, centrifuge at 4000r / min for 20min, and vacuum dry the product at 80℃ for 8h to obtain the modified diamond micro powder.

[0039] Example 6: Preparation of modified silane coupling agent. The specific preparation steps are as follows: B1. Take 25g of silane coupling agent KH-550 and 25g of silane coupling agent KH-560, add them to 100mL of toluene, stir to dissolve, and heat to 60℃; slowly add 10mL of hydroxyethyl acrylate, add 0.3g of azobisisobutyronitrile, purge with nitrogen for protection, and react at 200r / min for 4h; then add 8g of adipate dihydrazide, heat to 80℃, and stir to react for 3h; after the reaction is completed, remove toluene by vacuum distillation at -0.095MPa and 60℃ to obtain the first modified silane coupling agent; B2. Dissolve 50g of the first modified silane coupling agent in 80mL of dichloromethane, cool to 0℃, slowly add 12mL of epichlorohydrin, and stir the reaction at 150r / min for 2h; then heat to 25℃, add 6g of diethylenetriamine, and continue stirring the reaction for 4h. Adjust the pH of the system to 6 with hydrochloric acid, allow it to stand and separate into layers, take the organic phase, wash it twice with deionized water, and remove the dichloromethane by vacuum distillation at -0.095MPa and 50℃ to obtain the second modified silane coupling agent. B3. Dissolve 50g of the second modified silane coupling agent in 60mL of deionized water, add 3.2% sodium hydroxide solution to adjust the pH to 9, cool in a water bath to 5℃, and stir at 200r / min. Slowly add 15g of anhydrous sodium sulfite in 5 batches, adding the next batch only after no more bubbles are generated in the system. After all the additions are complete, continue stirring the reaction, maintaining the temperature ≤15℃. Stop the reaction when the pH of the system stabilizes at 3 and no irritating gas is released. Let the system stand for 30min, take the clear supernatant, add 8g of ammonium dihydrogen phosphate, and add sodium hydroxide solution dropwise to adjust the pH to 6.5. Stir at 200r / min and heat in a water bath to 70℃, and keep stirring for 3h. Then cool to room temperature, filter, and wash the filter cake twice with deionized water. Transfer the filter cake to a vacuum drying oven and dry at 60℃ for 5h to obtain the modified silane coupling agent.

[0040] Example 7: Preparation of modified silane coupling agent. The specific preparation steps are as follows: B1. Take 25g of silane coupling agent KH-550 and 25g of silane coupling agent KH-560, add them to 150mL of toluene, stir to dissolve, and heat to 70℃; slowly add 15mL of hydroxyethyl acrylate, add 0.6g of azobisisobutyronitrile, purge with nitrogen for protection, and react at 250r / min for 5h; then add 12g of adipate dihydrazide, heat to 90℃, and stir to react for 4h; after the reaction is completed, remove toluene by vacuum distillation at -0.095MPa and 60℃ to obtain the first modified silane coupling agent; B2. Dissolve 50g of the first modified silane coupling agent in 120mL of dichloromethane, cool to 5℃, slowly add 18mL of epichlorohydrin, and stir the reaction at 200r / min for 3h; then heat to 35℃, add 10g of diethylenetriamine, and continue stirring the reaction for 6h. Adjust the pH of the system to 7 with hydrochloric acid, allow it to stand and separate into layers, take the organic phase, wash it 3 times with deionized water, and remove the dichloromethane by vacuum distillation at -0.095MPa and 50℃ to obtain the second modified silane coupling agent. B3. Dissolve 50g of the second modified silane coupling agent in 80mL of deionized water, add 3.2% sodium hydroxide solution to adjust the pH to 10, cool in a water bath to 10℃, and stir at 200r / min. Slowly add 20g of anhydrous sodium sulfite in 5 batches, adding the next batch only after no more bubbles are generated in the system. After all the addition is complete, continue stirring the reaction, maintaining the temperature ≤15℃. Stop the reaction when the pH of the system stabilizes at 4 and no irritating gas is released. Let the system stand for 30min, take the clear supernatant, add 12g of ammonium dihydrogen phosphate, and add sodium hydroxide solution dropwise to adjust the pH to 7.0. Stir at 250r / min and heat in a water bath to 70℃, and keep stirring for 4h. Then cool to room temperature, filter, and wash the filter cake 3 times with deionized water. Transfer the filter cake to a vacuum drying oven and dry at 70℃ for 7h to obtain the modified silane coupling agent.

[0041] Comparative Example 1: A readily dispersible diamond polishing slurry was prepared. The specific preparation steps are as follows: The remaining steps remain the same, except that the modified diamond micro powder prepared in Example 4 used in Example 3 is replaced with unmodified diamond micro powder to prepare an easily dispersible diamond polishing slurry.

[0042] Comparative Example 2: A readily dispersible diamond polishing slurry was prepared. The specific preparation steps are as follows: The remaining steps remain unchanged, except that the modified silane coupling agent prepared in Example 7 and used in Example 3 are replaced with unmodified silane coupling agents KH-550 and KH-560 at a mass ratio of 1:1 to prepare an easily dispersible diamond polishing slurry.

[0043] Comparative Example 3: A readily dispersible diamond polishing slurry was prepared. The specific preparation steps are as follows: The remaining steps remain unchanged, except that the modified diamond micro powder prepared in Example 4 used in Example 3 is replaced with unmodified diamond micro powder, and the modified silane coupling agent prepared in Example 7 is replaced with unmodified silane coupling agent KH-550 and unmodified silane coupling agent KH-560 in a mass ratio of 1:1, to prepare an easily dispersible diamond polishing slurry.

[0044] Performance testing Test Project Test methods Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Microscopic observation of dispersibility The dispersion state of diamond powder in the polishing slurry was observed using transmission electron microscopy (TEM). The proportion of agglomerates by particle size was statistically analyzed. Agglomerates with a particle size >5μm were considered unqualified agglomerates. The unqualified agglomerates were graded according to the proportion of unqualified agglomerates: excellent (≤5%), good (6%-15%), medium (16%-30%), and poor (>30%). Good (12%) Good (8%) Excellent (3%) Middle (25%) China (22%) Poor (>30%) Measurement of suspension rate using graduated cylinder Take 100 mL of polishing slurry and place it in a 100 mL graduated cylinder. After standing at room temperature for 72 hours, determine the percentage of diamond powder in the upper 90 mL of polishing slurry relative to the initial total mass. 92.3% 95.7% 98.5% 75.1% 78.6% 62.4% Grinding efficiency Using a 4-inch sapphire wafer as the grinding target, the total thickness removed from the wafer (μm) was measured after 2 hours of grinding under the same grinding equipment (pressure 0.2 MPa, rotation speed 40 r / min). 125.6 142.3 158.8 82.4 89.7 65.2 Storage stability The grinding slurry was sealed and stored in a 50℃ constant temperature oven for 30 days. After removal, the layering and precipitation were observed, and the suspension retention rate was measured (suspension rate after storage / initial suspension rate × 100%). No stratification or sedimentation; retention rate 89.5%. No stratification or sedimentation; retention rate 93.2%. No stratification or sedimentation; retention rate 97.8%. Slight precipitation, retention rate 65.3%. Slight stratification, retention rate 68.7% Clearly stratified sedimentation, with a retention rate of 48.2%. Viscosity stability The initial viscosity (25℃, mPa·s) and the viscosity after storage at 50℃ for 30 days were measured using a rotational viscometer, and the viscosity change rate (%) was calculated. Initial value: 280, rate of change: 5.7% Initial value: 320, rate of change: 4.2% Initial value: 300, rate of change: 2.1% Initial value: 260, rate of change: 12.3% Initial value: 275, rate of change: 10.8% Initial value: 250, rate of change: 18.6% Performance test results show that the easily dispersible diamond polishing slurries of Examples 1-3 have significantly better overall performance than those of Comparative Examples 1-3: Example 3 performed best, achieving excellent dispersibility (3% of unqualified agglomerates), a suspension rate of 98.5% after 72 hours, a total thickness removal of 158.8 μm from sapphire wafers after 2 hours, no stratification or precipitation after 30 days of storage at 50℃, a suspension retention rate of 97.8%, and a viscosity change rate of only 2.1%. Examples 1-2 performed slightly worse but still reached good quality, exhibiting excellent dispersibility, suspension rate, polishing efficiency, and storage stability. Comparative Examples 1-3, however, due to the lack of modified diamond micropowder and / or modified silane coupling agent, exhibited severe agglomeration, low suspension rate, poor polishing efficiency, and stratification after storage, with a significantly higher viscosity change rate. This difference fully demonstrates the synergistic effect of modified diamond micropowder and modified silane coupling agent, which effectively reduces the agglomeration force of micropowder and enhances its affinity with aqueous systems, making it key to improving the dispersion stability, polishing efficiency, and storage performance of the polishing slurry.

[0045] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. An easily dispersible diamond polishing fluid, characterized in that: It contains the following raw materials in parts by weight: 1-20 parts modified diamond micro powder, 40-80 parts deionized water, 1-10 parts polyethylene glycol 6000, 0.5-1.2 parts sodium carboxymethyl cellulose, 1-20 parts glycerol, 1-10 parts triethanolamine, 0.3-0.7 parts sodium polyacrylate, 0.05-5 parts 1,2-benzisothiazolin-3-one, and 1-10 parts modified silane coupling agent.

2. The easily dispersible diamond polishing fluid according to claim 1, characterized in that: The modified diamond micro powder is prepared using the following specific steps: A1. First, add diamond micro powder to an ethanol-water mixture with a volume ratio of 3:1, stir to disperse and form a suspension, heat to 50-60℃, slowly add silane coupling agent KH-550, and stir at a constant temperature of 200-250 r / min for 2-3 h; continue to add maleic anhydride, heat to 70-80℃, and react for 4-5 h; after the reaction is completed, wash with deionized water by centrifugation at 4000 r / min 3-4 times, 10-15 min each time, and vacuum dry the product at 80-90℃ for 4-6 h to obtain the first modified diamond micro powder; A2. Take the first modified diamond micro powder, disperse it in deionized water, and ultrasonically disperse it at 300W for 30-40 min to form a uniform suspension. Adjust the pH to 9-10 with concentrated ammonia. Slowly add a 25% (w / w) tetraethyl orthosilicate toluene solution and stir at 150-200 r / min for 1-2 h at 40-50℃. Add epichlorohydrin to the system, heat to 60-70℃, and stir for 3-4 h. Then add nano-alumina with a particle size of 20-50 nm and continue stirring for 2-3 h. Wash with a 0.5% (w / w) citric acid solution at 40℃ for 30 min, then centrifuge, wash with deionized water until neutral, and vacuum dry at 60-70℃ for 5-7 h to obtain the second modified diamond micro powder. A3. Add the second modified diamond micro powder to N,N-dimethylformamide, ultrasonically disperse at 300W for 20-30 min, add 2-acrylamido-2-methylpropanesulfonic acid, purge with nitrogen at a flow rate of 45 sccm for protection, heat to 65-75℃, add ammonium persulfate, and react at 200-250 r / min for 3-4 h; continue to add dimethylaminoethyl methacrylate to the system, and continue to react for 2-3 h; after the reaction is completed, wash 2-3 times with a 1:2 volume ratio ethanol-deionized water mixed solution, centrifuge at 4000 r / min for 15-20 min, and vacuum dry the product at 70-80℃ for 6-8 h to obtain modified diamond micro powder.

3. The easily dispersible diamond polishing fluid according to claim 2, characterized in that: The diamond micro powder has a particle size of 0.5-10μm, with the D50 particle size controlled within the range of 1-3μm, to ensure a balance between cutting efficiency and surface finish during the grinding process.

4. The easily dispersible diamond polishing fluid according to claim 2, characterized in that: The ratio of diamond micro powder, ethanol-water mixed solution, silane coupling agent KH-550, and maleic anhydride in A1 is 100g: 300-400mL: 20-30mL: 15-25g. The ratio of the first modified diamond micro powder, deionized water, tetraethyl orthosilicate toluene solution, epichlorohydrin, and nano alumina in A2 is 100g: 250-350mL: 10-15mL: 8-12g: 5-10g. The ratio of the second modified diamond micro powder, N,N-dimethylformamide, 2-acrylamide-2-methylpropanesulfonic acid, ammonium persulfate, and dimethylaminoethyl methacrylate in A3 is 100g: 200-300mL: 12-18g: 0.5-1.0g: 8-15g.

5. The easily dispersible diamond polishing fluid according to claim 1, characterized in that: The modified silane coupling agent is prepared using the following specific steps: B1. Take silane coupling agents KH-550 and KH-560, add them to toluene, stir to dissolve, and heat to 60-70℃; slowly add hydroxyethyl acrylate, add azobisisobutyronitrile, purge with nitrogen for protection, and react at 200-250 r / min for 4-5 h; then add adipic acid dihydrazide, heat to 80-90℃, and stir to react for 3-4 h; after the reaction is completed, remove toluene by vacuum distillation at -0.095 MPa and 60℃ to obtain the first modified silane coupling agent; B2. Dissolve the first modified silane coupling agent in dichloromethane, cool to 0-5℃, slowly add epichlorohydrin, and stir the reaction at 150-200 r / min for 2-3 h; then raise the temperature to 25-35℃, add diethylenetriamine, and continue stirring the reaction for 4-6 h. Adjust the pH of the system to 6-7 with hydrochloric acid, allow it to stand and separate into layers, take the organic phase, wash it 2-3 times with deionized water, and remove the dichloromethane by vacuum distillation at -0.095 MPa and 50℃ to obtain the second modified silane coupling agent. B3. Dissolve the second modified silane coupling agent in deionized water, add 3.2% sodium hydroxide solution to adjust the pH to 9-10, cool in a water bath to 5-10℃, and stir at 200 rpm. Slowly add anhydrous sodium sulfite in 5 batches, adding the next batch only after no more bubbles are generated in the system. After all the addition is complete, continue stirring the reaction, maintaining the temperature ≤15℃. Stop the reaction when the pH of the system stabilizes at 3-4 and no irritating gas is released. Let the system stand for 30 minutes, take the clear supernatant, add ammonium dihydrogen phosphate, and add sodium hydroxide solution dropwise to adjust the pH to 6.5-7.

0. Stir at 200-250 rpm and heat in a water bath to 70℃, and keep stirring for 3-4 hours. Then cool to room temperature, filter, and wash the filter cake 2-3 times with deionized water. Transfer the filter cake to a vacuum drying oven and dry at 60-70℃ for 5-7 hours to obtain the modified silane coupling agent.

6. The easily dispersible diamond polishing fluid according to claim 5, characterized in that: The ratio of silane coupling agent KH-550, silane coupling agent KH-560, toluene, hydroxyethyl acrylate, azobisisobutyronitrile, and adipate dihydrazide in B1 is 25g:25g:100-150mL:10-15mL:0.3-0.6g:8-12g; The ratio of the first modified silane coupling agent, dichloromethane, epichlorohydrin, and diethylenetriamine in B2 is 50g:80-120mL:12-18mL:6-10g; The ratio of the second modified silane coupling agent, deionized water, anhydrous sodium sulfite, and ammonium dihydrogen phosphate in B3 is 50g: 60-80mL: 15-20g: 8-12g.

7. A method for preparing an easily dispersible diamond polishing slurry, characterized in that: Specifically, it includes the following steps: S1. Add 40-80 parts of deionized water to the reactor. Slowly add 1-10 parts of polyethylene glycol 6000 while stirring at 300-500 r / min. Heat to 40-50℃ and stir for 30-40 min until completely dissolved. Add 0.5-1.2 parts of sodium carboxymethyl cellulose and 0.3-0.7 parts of sodium polyacrylate to the system. Heat to 60-70℃ and increase the stirring speed to 600-800 r / min. Stir for 1-1.5 h to form a uniform pre-dispersed base liquid. The viscosity of the base liquid is measured to be 200-500 mPa·s. S2. Slowly add 1-20 parts of modified diamond micro powder to the pre-dispersed base liquid, while simultaneously dispersing using ultrasound at 400W, maintaining a stirring speed of 800-1000 r / min, and controlling the temperature at 50-60℃, for 1.5-2 hours; add 1-10 parts of modified silane coupling agent, continue ultrasonic dispersion, increase the stirring speed to 1200-1500 r / min, raise the temperature to 70-80℃, and react for 2-2.5 hours; S3. After completion, turn off the ultrasound, reduce the stirring speed to 600-800 r / min, and the temperature to 40-50℃. Slowly add 1-20 parts of glycerol to the system and stir for 30-40 min. Add 1-10 parts of triethanolamine dropwise to adjust the pH of the system to 8.0-8.5 and stir for 20-30 min, continuously monitoring the pH to ensure it remains stable within the target range. Then add 0.05-5 parts of 1,2-benzisothiazolin-3-one and stir for 30-40 min to ensure the antibacterial agent is evenly dispersed in the system. S4. Replace the stirring device in the reactor with a shear dispersion disc, and perform high-intensity shear dispersion at 30-40℃ and 2000-3000 r / min for 3-4 hours. After shear dispersion, cool the system to room temperature, perform primary filtration with a 2000-3000 mesh filter, and then perform secondary filtration using a plate and frame filter press with a filtration accuracy of 1-2 μm and a pressure of 0.3-0.5 MPa. S5. Transfer the filtered grinding slurry into the finished product tank and let it stand at room temperature for 24-48 hours for maturation treatment. During this period, stir at 300-500 r / min for 30 minutes every 6 hours. After maturation, fill and seal to obtain the finished product of easily dispersible diamond grinding slurry.

8. The method for preparing an easily dispersible diamond polishing slurry according to claim 7, characterized in that: In S2, the ultrasonic dispersion is operated intermittently, that is, the ultrasonic operation is paused for 10 minutes after 30 minutes, and the cycle is repeated until the end, while the distance between the ultrasonic probe and the liquid surface is controlled to be 2-3 cm.