Preparation method of SiO2 abrasive with cookie-like special morphology

Abstract

The invention relates to a preparation method of a cookie-like SiO2 abrasive with a special morphology. The preparation method comprises the following steps: 1) preparing nucleation silicon source hydrolysate; 2) preparing mother liquor; (3) preparing a primary nucleation liquid; (4) preparing a nucleation silicon source special-shaped solution; 5) preparing a growth silicon source hydrolysate; 6) adjusting the pH value of the nucleation silicon source profiled solution to 8-10; and (7) dropping the growth silicon source hydrolysate core into the solution in the step (6) at a constant speed, and carrying out growth reaction, so as to prepare the SiO2 grinding material with a cookie-like special morphology. A silanol hydrolysis method is adopted, improvement is carried out on the basis of an existing silanol hydrolysis method, reaction conditions for maintaining high purity of a product and easy to operate are reserved, double silicon sources are introduced, growth is regulated and controlled by adopting different conditions in a nucleation stage and a growth stage, and a new cookie-shaped morphology is obtained. On the basis of potato-shaped special shapes of the substrate and the small cores, the substrate and the small cores are combined, and the whole body is in embedded distribution and has a unique special shape.

Description

Technical Field

[0001] The present invention belongs to the technical field of material preparation, and particularly relates to a method for preparing a "cookie-shaped" special-shaped SiO2 abrasive. Background Art

[0002] The development of information technology has put forward higher requirements for the surface flatness of integrated circuits. Chemical mechanical polishing is one of the few surface polishing technologies that can meet such requirements. Currently, the mainstream polishing abrasives are still mainly nano-silica abrasives, which can be classified into spherical abrasives and non-spherical abrasives according to their morphologies. Spherical abrasives were the mainstream research direction for some time in the past, but spherical abrasives themselves are lacking in terms of removal rate. Therefore, many improvement methods have emerged, such as mesoporous treatment or preparation of core-shell structures, etc.

[0003] Heteromorphic abrasives have improved removal rate and removal effect compared with spherical abrasives, and many different morphologies have emerged, such as dumbbell-shaped, cocoon-shaped, columnar, dendritic, elliptical, petal-shaped, etc. Most of the heteromorphic morphologies are single heteromorphic methods, and the heteromorphic methods mostly use methods such as adding binders like cations and silane coupling agents for heteromorphic treatment. This treatment method is likely to introduce impurities, such as organic coupling agents and metal cations such as Ca 2+ etc.

[0004] In terms of preparation methods, currently, the preparation of nano-silica abrasives is mainly divided into three categories. The example ion exchange method with water glass (sodium silicate) as the main raw material is easy for large-scale production and has a low production cost. The elemental silicon hydrolysis method with elemental silicon as the main raw material introduces fewer external substances and the product components are pure, but the reaction is not complete, resulting in residues of reactants such as silicon powder. The silanol hydrolysis method with silanol as the main raw material, among which the widely used Stöber method has simple operation, stable reaction, and is easy for relatively large-scale reaction production. Its main silicon source is TEOS, and the reaction rate is relatively slow, and a catalytic reaction needs to be carried out under the condition of an alkaline catalyst. The main heteromorphic morphologies prepared by it are dumbbell-shaped, peanut-shaped, and potato-shaped. In addition, the multi-silicon source method, such as the mixed silicon source of TMOS and TEOS, is mostly used in the sol-gel method to prepare gel films. The gel films or aerogels prepared with different ratios of TMOS and TEOS have different indexes such as refractive index and light transmittance. By introducing TEOS and coordinating different ratios, the product effect can be improved.

[0005] Patent CN102164853A discloses the preparation of dense, high-purity colloidal silica abrasives with branched and curved structures by using an alkaline catalyst and the weak acidic pH value of the silanol hydrolysis solution itself, and the silicon source used is TMOS for preparation. The main morphologies of the prepared nano-silica abrasives are dendritic and branched, similar to cocoon-like and dumbbell-like. Patent CN119330359A reports a method for preparing high-purity silica sol using TMOS and an organic base, without mentioning the specific morphology. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the purpose of the design of the present invention is to provide a preparation method of "cookie-like" special morphology SiO2 abrasive to achieve a new morphology preparation method, provide a preparation idea for double-silicon-source abrasives, and specifically be realized through the following technical solutions: A preparation method of "cookie-like" special morphology SiO2 abrasive, which comprises the following steps: 1) React a high-reaction-rate silanol as a nucleating silicon source in an aqueous alcohol solution to obtain a nucleating silicon source hydrolysis solution; 2) Add an alkaline catalyst to deionized water and stir to adjust the pH value to 8-12 to obtain a mother liquor; 3) Slowly drip the nucleating silicon source hydrolysis solution obtained in step 1) into the mother liquor obtained in step 2) while stirring to obtain a preliminary nucleation solution; 4) When the pH value of the preliminary nucleation solution drops to 6-7, preferably 6.4, stop dripping the hydrolysis solution, control the pH value, and continue stirring and reacting to obtain a nucleating silicon source heteromorphosis solution; 5) React a low-reaction-rate silanol as a growth silicon source in an aqueous alcohol solution to obtain a growth silicon source hydrolysis solution; 6) Add an alkaline catalyst to the nucleating silicon source heteromorphosis solution prepared in step 4) until the pH value reaches 8-10, preferably 8; 7) Slowly drip the growth silicon source hydrolysis solution prepared in step 5) into the solution obtained in step 6) under stirring for growth reaction, and at the same time add a catalyst to control the pH value to be constantly 8-10 to prepare a "cookie-like" special morphology SiO2 abrasive.

[0007] Preferably, in step 1), the high-reaction-rate silanol is TMOS, the aqueous alcohol solution is a volume ratio of alcohol to deionized water of 0-80%, preferably 50%, and the molar ratio of deionized water to the nucleating silicon source is 8-60:1.

[0008] Preferably, in step 2), the alkaline catalyst is a nitrogen-containing organic base catalyst, and any one of ethylenediamine, diethylenetriamine, triethylenetetramine, ammonia, urea, monoethanolamine, diethanolamine, triethanolamine, tetramethylammonium hydroxide TMAH, and tetramethylguanidine is selected, preferably TMAH.

[0009] Preferably, the dropping rate of the nucleation silicon source hydrolysis solution in step 3) is 1 ml / min; the dropping rates of the growth silicon source hydrolysis solutions in step 7) are both 0.1 ml / min.

[0010] Preferably, in step 4), continuing the stirring reaction means stirring and reacting at 1000 rpm for 30 min.

[0011] Preferably, in step 5), the low reaction rate silanol is TEOS, the alcohol aqueous solution is a volume ratio of alcohol to deionized water of 0 - 80%, the molar ratio of deionized water to the nucleation silicon source is 8 - 60:1, the alcohol is an alcohol with 1 - 3 carbon atoms, and is any one of methanol, ethanol, propylene glycol, and isopropanol, preferably ethanol.

[0012] Preferably, in step 7), the growth reaction time is 12 - 72 h.

[0013] The present invention adopts the silanol hydrolysis method, improves on the basis of the existing publicly disclosed silanol hydrolysis method, retains the reaction conditions for maintaining the high purity of the product and easy operation, introduces a dual silicon source, controls the growth under different conditions in the nucleation stage and the growth stage, obtains a new "cookie-like" morphology, combines the two on the basis of the potato-shaped heteromorphism of the substrate and the small nuclei themselves respectively, and presents a mosaic distribution as a whole, with a unique heteromorphic morphology. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the process flow chart of the preparation of the present invention; Figure 2 is the TEM images of different positions of the sample prepared in Example 1; Figure 3 is the TEM images of different positions of the sample prepared in Example 2; Figure 4 is the TIM image of the sample prepared in Comparative Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The following further illustrates the present invention with specific embodiments for better understanding the technical solution.

[0016] The process flow chart of the preparation of the present invention is as Figure 1 shown. Example 1

[0017] 1) Prepare the nucleation silicon source hydrolysis solution: Take 13.5 ml of TMOS, 6 ml of EtOH, and 180 ml of H2O and add them to a beaker while stirring, and stir and react at 500 rpm for 1 h; 2) Preparation of mother liquor: Take 50 ml of H2O and 0.1 ml of TMAH (25% aqueous solution), add them to a beaker while stirring, and stir at 1000 rpm; 3) Primary nucleation: Slowly add the hydrolyzed solution of nucleating silicon source to the mother liquor at a constant speed of 1 ml / min while stirring, with a stirring rate of 1000 rpm to obtain a primary nucleation solution; 4) Heteromorphosis: Stop adding the hydrolyzed solution of nucleating silicon source when the pH reaches 6.5, control the pH to be stable, and continue to stir and react at 1000 rpm for 30 min to obtain a heteromorphosis solution of nucleating silicon source; 5) Preparation of hydrolyzed solution of growth silicon source: Take 50 ml of TEOS, 240 ml of H2O, and 240 ml of EtOH, add them to a beaker while stirring, and stir and react at 500 rpm for 1 h to obtain a hydrolyzed solution of growth silicon source; 6) Preparation of catalyst: Take 1 ml of TMAH (25% aqueous solution), 250 ml of H2O, and 250 ml of EtOH, add them to a beaker while stirring, and stir and react at 500 rpm for 1 h; 7) Growth: Slowly add the prepared hydrolyzed solution of growth silicon source and the catalyst to the heteromorphosis solution of nucleating silicon source at a rate of 0.1 ml / min while stirring for a growth reaction of 25 hours. The stirring rate for preparing the hydrolyzed solution and the catalyst is 500 rpm, and the stirring rate for preparing the mother liquor is 1000 rpm to obtain a "cookie-shaped" special morphology SiO2 abrasive.

[0018] TEM characterization diagrams of different parts of the "cookie-shaped" special morphology SiO2 abrasive prepared in this example at different magnification are as Figure 2 shown. It can be seen from Figure 2 that SiO2 particles are embedded on a larger SiO2 substrate, jointly forming a "cookie-shaped" structure.

[0019] Example 2

[0020] 1) Preparation of hydrolyzed solution of nucleating silicon source: Take 13.5 ml of TMOS, 6 ml of EtOH, and 180 ml of H2O, add them to a beaker while stirring, and stir and react at 500 rpm for 1 h; 2) Preparation of mother liquor: Take 40 ml of H2O and 0.1 ml of TMAH (25% aqueous solution), add them to a beaker while stirring, and stir at 1000 rpm; 3) Primary nucleation: Slowly add the hydrolyzed solution of nucleating silicon source to the mother liquor at a constant speed of 1 ml / min while stirring, with a stirring rate of 1000 rpm to obtain a primary nucleation solution; 4) Heteromorphosis: Stop adding the hydrolyzed solution of nucleating silicon source when the pH reaches 6.4, control the pH to be stable, and continue to stir and react at 1000 rpm for 30 min to obtain a heteromorphosis solution of nucleating silicon source; 5) Preparation of the growth silicon source hydrolysis solution: Take 25.63 ml of TEOS, 15.75 ml of TMOS, 240 ml of H2O, and 240 ml of EtOH, and add them to a beaker while stirring. Stir and react at 500 rpm for 1 h to obtain the growth silicon source hydrolysis solution; 6) Preparation of the catalyst: Take 1 ml of TMAH (25% aqueous solution), 250 ml of H2O, and 250 ml of EtOH, and add them to a beaker while stirring. Stir and react at 500 rpm for 1 h; 7) Growth: Add the prepared growth silicon source hydrolysis solution and the catalyst to the nucleating silicon source heteromorphic solution at a rate of 0.1 ml / min while stirring, and carry out the growth reaction for 25 hours. The stirring rate for preparing the hydrolysis solution and the catalyst is 500 rpm, and the stirring rate for preparing the mother liquor is 1000 rpm to obtain the "cookie-like" special morphology SiO2 abrasive.

[0021] TEM characterization diagrams of different parts of the "cookie-like" special morphology SiO2 abrasive prepared in this example at different magnification are as Figure 3 shown. From Figure 3 it can be seen that the "cookie-like" structure SiO2 abrasive can also be prepared by using a mixed silicon source.

[0022] Comparative Example 1 1) Preparation of the nucleating silicon source hydrolysis solution: Take 13.5 ml of TMOS, 6 ml of EtOH, and 180 ml of H2O, and add them to a beaker while stirring. Stir and react at 500 rpm for 1 h; 2) Preparation of the mother liquor: Take 40 ml of H2O and 0.1 ml of TMAH (25% aqueous solution), and add them to a beaker while stirring. Stir at 1000 rpm; 3) Preliminary nucleation: Add the nucleating silicon source hydrolysis solution to the mother liquor at a constant speed of 1 ml / min while stirring, with a stirring rate of 1000 rpm to obtain the preliminary nucleation solution; 4) Heteromorphism: Stop adding the nucleating silicon source hydrolysis solution when the pH reaches 6.4, control the pH to be stable, and continue to stir and react at 1000 rpm for 30 min to obtain the nucleating silicon source heteromorphic solution; 5) Preparation of the growth silicon source hydrolysis solution: Take 31.5 ml of TMOS, 240 ml of H2O, and 240 ml of EtOH, and add them to a beaker while stirring. Stir and react at 500 rpm for 1 h to obtain the growth silicon source hydrolysis solution; 6) Preparation of the catalyst: Take 1 ml of TMAH (25% aqueous solution), 250 ml of H2O, and 250 ml of EtOH, and add them to a beaker while stirring. Stir and react at 500 rpm for 1 h; 7) Growth: The prepared growth silicon source hydrolysis solution and 0.1 ml / min of the catalyst were added to the nucleation silicon source heteromorphic solution with stirring for a growth reaction for 25 hours. The stirring rate for preparing the hydrolysis solution and the catalyst was 500 rpm, and the stirring rate for preparing the mother liquor was 1000 rpm to obtain the SiO2 abrasive.

[0023] The TEM characterization diagram of the SiO2 abrasive prepared in this example is as Figure 4 shown. From Figure 4 it can be seen that "cookie-shaped" SiO2 abrasive cannot be obtained by using pure TMOS as the nucleation silicon source and the growth silicon source, and it is necessary to introduce TEOS as a component of the growth silicon source.

Claims

1. A method for preparing a "cookie-like" special morphology SiO2 abrasive, characterized in that: The preparation method comprises the following steps: 1) Using high-reaction-rate silanol as a nucleation silicon source to react in an alcohol-water solution to obtain a nucleation silicon source hydrolyzate; 2) adding the alkaline catalyst to deionized water with stirring, adjusting the pH value to 8-12, to obtain a mother liquor; 3) uniformly adding the hydrolyzed nucleation silicon source solution from step 1) to the mother solution from step 2) while stirring to obtain a preliminary nucleation solution; 4) When the pH value of the initial nucleation solution drops to 6-7, stop adding the hydrolyzate, control the pH value, and continue stirring the reaction to obtain a nucleation silicon source heterogeneous solution; 5) Using low-reaction-rate silanol as a silicon growth source to react in an alcohol-water solution to obtain a silicon growth source hydrolyzate; 6) adding a basic catalyst dropwise to the nucleation silicon source anisotropic solution obtained in step 4) to a pH value of 8-10; 7) While stirring, the growth silicon source hydrolyzate obtained in step 5) is uniformly added dropwise to the solution in step 6) to carry out a growth reaction. Simultaneously, a catalyst is added dropwise to control the pH value to be constant at 8-10, thereby obtaining a SiO2 abrasive with a special "cookie-like" morphology.

2. The method for preparing a SiO2 abrasive with a special "cookie-like" morphology as claimed in claim 1, characterized in that In step 1), TMOS is selected as a high reaction rate silanol, the alcohol aqueous solution has a volume ratio of alcohol to deionized water of 0-80%, and the molar ratio of deionized water to nucleation silicon source is 8-60:

1.

3. The method for preparing a SiO2 abrasive with a special "cookie-like" morphology as claimed in claim 1, characterized in that In step 2), the alkaline catalyst is a nitrogen-containing organic base catalyst, and any one of ethylenediamine, diethylenetriamine, triethylenetetramine, ammonia, urea, monoethanolamine, diethanolamine, triethanolamine, tetramethylammonium hydroxide TMAH, and tetramethylguanidine is selected.

4. The method for preparing a SiO2 abrasive with a special "cookie-like" morphology as claimed in claim 1, characterized in that The drop-wise acceleration rate of the nucleation silicon source hydrolyzate in step 3) is 1 ml / min; the drop-wise acceleration rate of the growth silicon source hydrolyzate in step 7) is 0.1 ml / min.

5. The method for preparing a SiO2 abrasive with a special "cookie-like" morphology as claimed in claim 1, characterized in that In step 4), continuing to stir the reaction means continuing to stir the reaction at 1000 rpm for 30 minutes.

6. The method for preparing a SiO2 abrasive with a special cookie-like morphology as claimed in claim 1, characterized in that In step 5), the low-reaction-rate silanol is TEOS, the alcohol-water solution is a 0-80% volume ratio of alcohol to deionized water, the molar ratio of deionized water to the nucleation silicon source is 8-60:1, and the alcohol is an alcohol having 1-3 carbon atoms, which is any one of methanol, ethanol, propylene glycol, and isopropanol.

7. The method for preparing a SiO2 abrasive with a special "cookie-like" morphology as claimed in claim 1, characterized in that In step 7), the growth reaction time is 12-72 hours.

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