Preparation method of high-purity spherical silica sol for electronic polishing

Abstract

The invention provides a preparation method of high-purity spherical silica sol for electronic polishing, and relates to the field of inorganic compound materials.The preparation method comprises the steps that tetramethoxysiloxane and dispersion liquid are simultaneously injected from two feeding ports of a first-stage silicon carbide microchannel reactor for a hydrolytic polymerization reaction, and a solution A is obtained; simultaneously feeding the solution A and the acidic hydrolysate from two feeding holes of a second-stage silicon carbide microchannel reactor, and carrying out a particle homogenization reaction to obtain a solution B; simultaneously feeding the solution B and a stabilizer from two feeding holes of a third-stage silicon carbide micro-channel reactor, and carrying out particle stability reaction to obtain high-purity spherical silica sol; and carrying out solvent replacement on the high-purity spherical silica sol, and concentrating the high-purity spherical silica sol through a membrane filter until the content of silicon dioxide is greater than 20% to obtain the ultra-high-purity spherical silica sol of which the total metal ion content is less than 1ppm. The prepared high-purity spherical silica sol is uniform in particle size, and the polishing effect can be improved.

Description

Technical Field

[0001] The invention relates to the field of electronic-grade high-purity inorganic silicon compound materials, and in particular to a method for preparing high-purity spherical silica sol for electronic polishing. Background Art

[0002] Silica sol is a dispersion of nano-scale silicon dioxide particles in water or solvent. Since SiO2 in silica sol contains a large amount of water and hydroxyl groups, it is a colloidal solution with properties such as odorlessness, non-toxicity, high dispersibility and high temperature resistance. It is widely used in papermaking, casting, coatings and chemical mechanical polishing. In recent years, silica sol for electronic polishing has been widely used in chemical mechanical polishing of semiconductor devices and semiconductor materials such as silicon, germanium, and indium phosphide. With the development of semiconductor devices, the requirements for device surface quality and precision are getting higher and higher. The metal ions contained in silica sol, the morphology state of silica sol and the particle size have a serious impact on its application. The existing silica sol preparation method has the following defects: the hydrolysis polymerization reaction rate is difficult to control, the metal ion content is high, the silica sol particles are uneven in size, and the particle size and particle shape are difficult to control.

[0003] Therefore, how to prepare spherical silica sol with uniform particle size and improved electronic polishing effect becomes a technical problem that needs to be solved. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art or related technology, and provides a method for preparing high-purity spherical silica sol for electronic polishing. The prepared high-purity spherical silica sol has uniform particle size and can improve the electronic polishing effect.

[0005] The first aspect of the present invention discloses a method for preparing high-purity spherical silica sol for electronic polishing, comprising: injecting tetramethoxysiloxane and a dispersion liquid simultaneously from two feed ports of a first-stage silicon carbide microchannel reactor, wherein the injection speed of tetramethoxysiloxane is 1.5-2.1 ml / min, and the injection speed of the dispersion liquid is 3.0-16.8 ml / min, wherein the dispersion liquid comprises a complex alcohol, ultrapure water and a weak base; performing a hydrolysis polymerization reaction under a temperature condition of 5-15°C, controlling the temperature fluctuation during the reaction process within 1.2°C, and obtaining a solution A from the outlet of the first-stage silicon carbide microchannel reactor; connecting the outlet of the first-stage silicon carbide microchannel reactor to a second-stage silicon carbide microchannel reactor, injecting the solution A and the acidic hydrolyzate from the outlet of the second-stage silicon carbide microchannel reactor; The two feed ports are injected simultaneously, and the injection speed of the acidic hydrolyzate is 9.0~95.0ml / min; the acidic hydrolyzate includes tetramethoxysiloxane, ultrapure water and acid, and the pH value is 2~4; the particle homogenization reaction is carried out at a temperature of 50~85°C, and a B solution is obtained from the outlet of the second-stage silicon carbide microchannel reactor; the outlet of the second-stage silicon carbide microchannel reactor is connected to the third-stage silicon carbide microchannel reactor, and the B solution and the stabilizer are injected from the two feed ports of the third-stage silicon carbide microchannel reactor at the same time, and the injection speed of the stabilizer is 0.01~9.1ml / min; the stabilizer includes ultrapure water, an organic base and a viscosity reducer; the particle stability reaction is carried out at a temperature of 20~30°C, and a high-purity spherical silica sol is obtained from the outlet of the third-stage silicon carbide microchannel reactor.

[0006] The method for preparing high-purity spherical silica sol for electronic polishing provided by the present invention preferably further comprises: collecting the high-purity spherical silica sol prepared by the third-stage silicon carbide microchannel reactor into a reaction kettle, heating it to 100°C while adding ultrapure water to maintain a constant liquid level, and performing solvent replacement; concentrating the high-purity spherical silica sol after solvent replacement through a membrane filter, and concentrating it to a silicon dioxide content of more than 20%, so as to obtain an ultra-high-purity spherical silica sol with a total metal ion content of less than 1 ppm.

[0007] According to the method for preparing high-purity spherical silica sol for electronic polishing provided by the present invention, preferably, the mass ratio of tetramethoxysiloxane to the dispersion liquid is 1:2~8; the mass ratio of the complex alcohol, ultrapure water and weak base in the dispersion liquid is 10:1.3~1.8:0.1~0.5.

[0008] According to the method for preparing high-purity spherical silica sol for electronic polishing provided by the present invention, preferably, the complex alcohol is a mixture of two or more of isopropanol, methanol, methyl ether, ethanol and acetone; the weak base is a mixture of two or more of ammonia water, monoethanolamine, diethanolamine, triethanolamine and ethylenediamine.

[0009] According to the method for preparing high-purity spherical silica sol for electronic polishing provided by the present invention, preferably, the mass ratio of solution A to the acidic hydrolyzate is 1:3-5; the mass ratio of tetramethoxysiloxane, ultrapure water and acid in the acidic hydrolyzate is 1:2-5:0.01-0.001.

[0010] According to the method for preparing high-purity spherical silica sol for electronic polishing provided by the present invention, preferably, the mass ratio of B solution to stabilizer is 100:1-8; the mass ratio of ultrapure water, organic base and viscosity reducer in the stabilizer is 100:2-6:0.05-0.1.

[0011] According to the method for preparing high-purity spherical silica sol for electronic polishing provided by the present invention, preferably, the acid includes a mixture of one or more of sulfuric acid, hydrochloric acid, nitric acid, oxalic acid, citric acid and acetic acid; the organic base includes ethylenediamine and / or tetramethylammonium hydroxide; and the viscosity reducer includes polyethylene glycol and / or nonylphenol.

[0012] According to the method for preparing high-purity spherical silica sol for electronic polishing provided by the present invention, preferably, the total ion content of sodium ions, aluminum ions, copper ions, iron ions, calcium ions, magnesium ions and potassium ions in tetramethoxysiloxane, complex alcohol, weak base, acid, organic base and viscosity reducer used in the reaction process is less than 1 ppb.

[0013] According to the method for preparing high-purity spherical silica sol for electronic polishing provided by the present invention, preferably, the pumps, pipelines, valves and storage tanks that contact the materials during the reaction process are all made of non-metallic materials, and the first-stage silicon carbide microchannel reactor, the second-stage silicon carbide microchannel reactor and the third-stage silicon carbide microchannel reactor are sealed and connected to form a closed reaction environment.

[0014] The second aspect of the present invention further discloses a high-purity spherical silica sol for electronic polishing, which is prepared according to the preparation method of the high-purity spherical silica sol for electronic polishing disclosed in any of the above technical solutions.

[0015] The beneficial effects achieved by the present invention include at least: utilizing the advantages of the microchannel reactor and the special reaction conditions, effectively controlling the speed of the hydrolysis polymerization reaction, solving the problem that the speed of the hydrolysis polymerization reaction of tetramethoxysiloxane is difficult to control, and successfully preparing ultra-high purity spherical silica sol with high stability and good uniformity. The method has the advantages of simple operation and a closed reaction process, can avoid air pollution and does not volatilize harmful substances, and can be produced continuously. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The figure shows a schematic flow chart of a method for preparing high-purity spherical silica sol for electronic polishing according to an embodiment of the present invention.

[0017] Figure 2 A schematic diagram of the microscopic morphology of high-purity spherical silica sol for electronic polishing according to an embodiment of the present invention is shown.

[0018] Figure 3 A schematic diagram of the microscopic morphology of high-purity spherical silica sol for electronic polishing according to yet another embodiment of the present invention is shown.

[0019] Figure 4 A schematic diagram of the microscopic morphology of high-purity spherical silica sol for electronic polishing according to yet another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0020] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, according to one embodiment of the present invention, a method for preparing high-purity spherical silica sol for electronic polishing is disclosed, comprising:

[0022] Step S1, hydrolysis polymerization reaction: tetramethoxysiloxane and the dispersion are simultaneously introduced into the two feed ports of the first-stage silicon carbide microchannel reactor, and a hydrolysis polymerization reaction is carried out at a temperature of 5-15°C. During the reaction, the temperature fluctuation is less than 1.2°C, and a solution A is obtained from the outlet of the silicon carbide microchannel reactor.

[0023] In this step, tetramethoxysiloxane is easily dispersed in the complex alcohol, which is beneficial to the hydrolysis polymerization reaction and avoids the problem of violent local reaction caused by uneven dispersion, resulting in uneven particle size. The reaction process of tetramethoxysiloxane releases heat. The higher the temperature, the faster the hydrolysis polymerization reaction, which affects the formation of silica sol. The weak base is a mixture of two or more of ammonia water, monoethanolamine, diethanolamine, triethanolamine and ethylenediamine. The weak base has a strong pH stability, and the pH value fluctuates little during the reaction process, which is beneficial to stabilize the hydrolysis polymerization reaction rate. The mass ratio of tetramethoxysiloxane to the dispersion is 1:2-8, the injection speed of tetramethoxysiloxane is 1.5-2.1ml / min, and the injection speed of the dispersion is 3.0-16.8ml / min. The dispersion liquid is a composite alcohol, ultrapure water and weak base, with a ratio of 10:1.3-1.8:0.1-0.5; the composite alcohol is a mixture of isopropanol and two or more of methanol, methyl ether, ethanol and acetone, and two or more of methanol, methyl ether, ethanol and acetone are taken to form a mixture, and 1-3 parts by mass of the mixture is mixed with 10 parts by mass of isopropanol to obtain the composite alcohol. The temperature of the silicon carbide microchannel reactor is controlled at 5-15°C, with the optimal selection of 8-13°C, the reaction temperature fluctuation is less than 1.2°C, and the optimal reaction temperature fluctuation is less than 0.8°C.

[0024] Step S2, particle homogenization reaction: Solution A and acidic hydrolyzate are simultaneously injected from two feed ports of the second-stage silicon carbide microchannel reactor, and a particle homogenization reaction is performed at a temperature of 50-85° C., and solution B is obtained from the outlet of the second-stage silicon carbide microchannel reactor.

[0025] In this step, the acidic hydrolyzate is a mixture of tetramethoxysiloxane, ultrapure water and acid, with a mass ratio of 1:2-5:0.01-0.001, a pH of 2-4, and an optimal pH of 2-3. The mass ratio of solution A to the acidic hydrolyzate is 1:2-5, and the injection speed of the acidic hydrolyzate is 9.0-95.0 ml / min. The optimal temperature is 70-80°C.

[0026] Step S3, particle stabilization reaction: inject solution B and stabilizer simultaneously from two feed ports of the third-stage silicon carbide microchannel reactor, carry out particle stabilization reaction at a temperature of 20-30°C, and obtain high-purity spherical silica sol with high particle uniformity and good stability from the outlet of the third-stage silicon carbide microchannel reactor.

[0027] In this step, the mass ratio of solution B to stabilizer is 100:1-8, and the injection speed of stabilizer is 0.01-9.1 ml / min. The stabilizer is a mixture of ultrapure water, organic strong base and viscosity reducer, and the mass ratio is 100:2-6:0.05-0.1. The organic strong base includes ethylenediamine and tetramethylammonium hydroxide. The viscosity reducer includes polyethylene glycol and nonylphenol.

[0028] Step S4, solvent replacement: collect the high-purity spherical silica sol produced by the third-stage silicon carbide microchannel reactor into a reactor, heat it to 100°C, and add ultrapure water to maintain a constant liquid level. When the alcohol content is detected to be less than 0.1 g / L, the solvent replacement is completed.

[0029] Step S5, concentration: the high-purity spherical silica sol after solvent replacement is concentrated through a membrane filter to a silicon dioxide content of more than 20%, thereby obtaining an ultra-high-purity spherical silica sol with a total metal ion content of less than 1 ppm.

[0030] According to the above embodiments, the present invention adopts the following method to control the purity of silica sol: (1) the total ion content of sodium ion, aluminum ion, copper ion, iron ion, calcium ion, magnesium ion and potassium ion in tetramethoxysiloxane, complex alcohol, weak base, acid, organic base and viscosity reducer used in the reaction process is less than 1 ppb; (2) the reactor used is made of non-metallic material, and can feed two or more materials at the same time, and the feed flow rate range is 0-200 ml / min, and can accurately control the temperature within 0-150°C, with a temperature difference of less than 0.5°C, supporting continuous production; (3) the pumps, pipelines, valves and storage tanks that contact the materials during the reaction process are all made of non-metallic materials, and the first-stage silicon carbide microchannel reactor, the second-stage silicon carbide microchannel reactor and the third-stage silicon carbide microchannel reactor are sealed and connected to form a closed reaction environment.

[0031] like Figure 2 , Figure 3 and Figure 4 As shown, according to another embodiment of the present invention, the specific implementation of the method for preparing the high-purity spherical silica sol for electronic polishing provided in the above embodiment is also disclosed:

[0032] Embodiment 1:

[0033] Isopropanol, ethanol, ultrapure water and ammonia water were mixed in a mass ratio of 4:6:1.5:0.3 to obtain a dispersion. Tetramethoxysiloxane, ultrapure water and hydrochloric acid were mixed in a mass ratio of 1:3:0.004 to obtain an acidic hydrolyzate having a pH of 2.3. Ultrapure water, ethylenediamine and polyethylene glycol were mixed in a mass ratio of 100:3:0.06 to obtain a stabilizer. The temperature of the primary silicon carbide microchannel reactor was set to 12.0°C, the injection rate of tetramethoxysiloxane was set to 1.7ml / min, the injection rate of the dispersion was set to 11.9ml / min, the temperature of the secondary silicon carbide microchannel reactor was set to 76°C, the injection rate of the acidic hydrolyzate was set to 9.5ml / min, the temperature of the tertiary silicon carbide microchannel reactor was set to 22°C, and the injection rate of the stabilizer was set to 0.4ml / min. When the temperature was reached, the primary, secondary and tertiary pumps were opened in sequence to start the reaction. When the reaction temperature fluctuation of the primary, secondary and tertiary silicon carbide microchannel reactors was less than 0.8°C, a high-purity spherical silica sol with a particle size of 16nm was obtained from the outlet of the third-stage silicon carbide microchannel reactor. The high-purity spherical silica sol produced by the third-stage silicon carbide microchannel reactor was collected in a reactor, heated to 100°C, and ultrapure water was added to maintain a constant liquid level. When the alcohol content was detected to be less than 0.1g / L, the solvent replacement was completed. The high-purity spherical silica sol after solvent replacement is concentrated to a silica content of 25% through a membrane filter to obtain an ultra-high-purity silica sol with a total metal ion content of 0.3 ppm, and its particle morphology is spherical, such as Figure 2 shown.

[0034] Example 2: Preparation of 78nm spherical silica sol;

[0035] Isopropanol, ethanol, ultrapure water and triethanolamine were mixed in a mass ratio of 2:8:1.5:0.2 to obtain a dispersion. Tetramethoxysiloxane, ultrapure water and sulfuric acid were mixed in a mass ratio of 1:3:0.006 to obtain an acidic hydrolyzate having a pH of 2.1. Ultrapure water, tetramethylammonium hydroxide and polyethylene glycol were mixed in a mass ratio of 100:2:0.06 to obtain a stabilizer. The temperature of the first-stage silicon carbide microchannel reactor is set to 13.0°C, the injection rate of tetramethoxysiloxane is set to 1.8ml / min, the injection rate of the dispersion is set to 11.6ml / min, the temperature of the second-stage silicon carbide microchannel reactor is set to 77°C, the injection rate of the acidic hydrolyzate is set to 10.5ml / min, the temperature of the third-stage silicon carbide microchannel reactor is set to 22°C, and the injection rate of the stabilizer is set to 0.3ml / min. When the temperature is reached, the first, second and third-stage pumps are opened in sequence to start the reaction. When the reaction temperature fluctuation of the first, second and third-stage silicon carbide microchannel reactors is less than 0.8°C, a high-purity spherical silica sol with a particle size of 78nm is obtained from the outlet of the third-stage silicon carbide microchannel reactor. The high-purity spherical silica sol produced by the third-stage silicon carbide microchannel reactor is collected in a reactor, heated to 100°C, and ultrapure water is added to maintain a constant liquid level. When the alcohol content is detected to be less than 0.1g / L, the solvent replacement is completed. The high-purity spherical silica sol after solvent replacement is concentrated to a silica content of 26% through a membrane filter to obtain an ultra-high-purity silica sol with a total metal ion content of 0.2 ppm, and its particle morphology is spherical, such as Figure 3 shown.

[0036] Example 3: Preparation of 118 nm spherical silica sol;

[0037] Methanol, ethanol, ultrapure water and triethanolamine were mixed in a mass ratio of 1:9:1.5:0.2 to obtain a dispersion. Tetramethoxysiloxane, ultrapure water and citric acid were mixed in a mass ratio of 1:3:0.009 to obtain an acidic hydrolyzate having a pH of 2.8. Ultrapure water, tetramethylammonium hydroxide and nonylphenol were mixed in a mass ratio of 100:2:0.08 to obtain a stabilizer. The temperature of the primary silicon carbide microchannel reactor was set to 13.0°C, the injection rate of tetramethoxysiloxane was set to 2.0ml / min, the injection rate of the dispersion was set to 12.8ml / min, the temperature of the secondary silicon carbide microchannel reactor was set to 77°C, the injection rate of the acidic hydrolyzate was set to 18.1ml / min, the temperature of the tertiary silicon carbide microchannel reactor was set to 23°C, and the injection rate of the stabilizer was set to 0.4ml / min. When the temperature was reached, the primary, secondary and tertiary pumps were opened in sequence to start the reaction. When the reaction temperature fluctuation of the primary, secondary and tertiary silicon carbide microchannel reactors was less than 0.8°C, a high-purity spherical silica sol with a particle size of 118nm was obtained from the outlet of the third-stage silicon carbide microchannel reactor. The high-purity spherical silica sol produced by the third-stage silicon carbide microchannel reactor was collected in a reactor, heated to 100°C, and ultrapure water was added to maintain a constant liquid level. When the alcohol content was detected to be less than 0.1g / L, the solvent replacement was completed. The high-purity spherical silica sol after solvent replacement is concentrated to a silica content of 28% through a membrane filter to obtain an ultra-high-purity silica sol with a total metal ion content of 0.4 ppm, and its particle morphology is spherical, such as Figure 4 shown.

[0038] According to another embodiment of the present invention, a high-purity spherical silica sol for electronic polishing is disclosed. The high-purity spherical silica sol for electronic polishing is prepared according to the preparation method of the high-purity spherical silica sol for electronic polishing disclosed in any of the above embodiments.

[0039] In summary, the above embodiment utilizes the advantages of the microchannel reactor and special reaction conditions, can effectively control the speed of the hydrolysis polymerization reaction, solves the problem that the speed of the hydrolysis polymerization reaction of tetramethoxysiloxane is difficult to control, and successfully prepares ultra-high purity silica sol with high stability and good uniformity. The method has the advantages of simple operation, closed reaction process, avoidance of air pollution, non-volatile harmful substances, and continuous production.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing high-purity spherical silica sol for electronic polishing, characterized in that: include: Simultaneously injecting tetramethoxysiloxane and a dispersion liquid from two feed ports of a first-stage silicon carbide microchannel reactor, wherein the injection rate of tetramethoxysiloxane is 1.5-2.1 ml / min, and the injection rate of the dispersion liquid is 3.0-16.8 ml / min, wherein the dispersion liquid comprises a complex alcohol, ultrapure water and a weak base; performing a hydrolysis polymerization reaction at a temperature of 5-15° C., controlling the temperature fluctuation during the reaction process within 1.2° C., and obtaining a solution A from the outlet of the first-stage silicon carbide microchannel reactor; The outlet of the first-stage silicon carbide microchannel reactor is connected to the second-stage silicon carbide microchannel reactor, and the A solution and the acidic hydrolyzate are simultaneously injected from the two feed ports of the second-stage silicon carbide microchannel reactor, and the injection rate of the acidic hydrolyzate is 9.0-95.0 ml / min; the acidic hydrolyzate comprises tetramethoxysiloxane, ultrapure water and acid, and the pH value is 2-4; a particle homogenization reaction is performed at a temperature of 50-85° C., and a B solution is obtained from the outlet of the second-stage silicon carbide microchannel reactor; The outlet of the second-stage silicon carbide microchannel reactor is connected to the third-stage silicon carbide microchannel reactor, and the B solution and the stabilizer are simultaneously injected from the two feed ports of the third-stage silicon carbide microchannel reactor, and the injection rate of the stabilizer is 0.01-9.1 ml / min; the stabilizer includes ultrapure water, an organic base and a viscosity reducer; a particle stability reaction is carried out at a temperature of 20-30° C., and a high-purity spherical silica sol is obtained from the outlet of the third-stage silicon carbide microchannel reactor.

2. The method for preparing high-purity spherical silica sol for electronic polishing according to claim 1, characterized in that: Also includes: The high-purity spherical silica sol prepared by the third-stage silicon carbide microchannel reactor is collected into a reaction kettle, heated to 100° C. and ultrapure water is added to maintain a constant liquid level to perform solvent replacement; The high-purity spherical silica sol after solvent replacement is concentrated through a membrane filter to a silicon dioxide content greater than 20%, thereby obtaining an ultra-high-purity spherical silica sol with a total metal ion content less than 1 ppm.

3. The method for preparing high-purity spherical silica sol for electronic polishing according to claim 1, characterized in that: The mass ratio of tetramethoxysiloxane to the dispersion is 1:2~8; the mass ratio of the complex alcohol, ultrapure water and weak base in the dispersion is 10:1.3~1.8:0.1~0.

5.

4. The method for preparing high-purity spherical silica sol for electronic polishing according to claim 3, characterized in that: The complex alcohol is a mixture of two or more of isopropanol, methanol, methyl ether, ethanol and acetone; the weak base is a mixture of two or more of ammonia water, monoethanolamine, diethanolamine, triethanolamine and ethylenediamine.

5. The method for preparing high-purity spherical silica sol for electronic polishing according to claim 1, characterized in that: The mass ratio of solution A to the acidic hydrolyzate is 1:3~5; the mass ratio of tetramethoxysiloxane, ultrapure water and acid in the acidic hydrolyzate is 1:2~5:0.01~0.

001.

6. The method for preparing high-purity spherical silica sol for electronic polishing according to claim 1, characterized in that: The acid includes one or more of sulfuric acid, hydrochloric acid, nitric acid, oxalic acid, citric acid and acetic acid; the mass ratio of B solution to stabilizer is 100:1~8; the mass ratio of ultrapure water, organic base and viscosity reducer in the stabilizer is 100:2~6:0.05~0.

1.

7. The method for preparing high-purity spherical silica sol for electronic polishing according to claim 6, characterized in that: The organic base includes ethylenediamine and / or tetramethylammonium hydroxide; the viscosity reducer includes polyethylene glycol and / or nonylphenol.

8. The method for preparing high-purity spherical silica sol for electronic polishing according to any one of claims 1 to 7, characterized in that: The total ion content of the sodium ion, aluminum ion, copper ion, iron ion, calcium ion, magnesium ion and potassium ion in the tetramethoxysiloxane, the complex alcohol, the weak base, the acid, the organic base and the viscosity reducer used in the reaction process is less than 1 ppb.

9. The method for preparing high-purity spherical silica sol for electronic polishing according to any one of claims 1 to 7, characterized in that: The pumps, pipelines, valves and storage tanks that contact the materials during the reaction process are all made of non-metallic materials. The first-stage silicon carbide microchannel reactor, the second-stage silicon carbide microchannel reactor and the third-stage silicon carbide microchannel reactor are sealed and connected to form a closed reaction environment. 10 . High-purity spherical silica sol for electronic polishing obtained by the preparation method according to any one of claims 1 to 9.

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