CeO2@ZSM-5 composite abrasive grain, and preparation method and application thereof

Abstract

The application discloses a CeO2@ZSM-5 composite abrasive particle and a preparation method and application thereof. The CeO2@ZSM-5 composite abrasive particle is prepared by loading CeO2 nanoparticles on the surface of ZSM-5 molecular sieve through an in-situ precipitation method. The introduction of ZSM-5 effectively inhibits the agglomeration of CeO2 nanoparticles, and the microporous structure of ZSM-5 can adsorb and enrich H2O2 to construct a local high-reactivity environment at the abrasive particle interface. The Brønsted acid and Lewis acid sites in the molecular sieve can synergistically promote the catalytic decomposition of H2O2 and stabilize the active cerium species. The CeO2 and ZSM-5 form a synergistic mechanism of "catalytic decomposition-pore enrichment-acid activation", which significantly improves the generation efficiency of hydroxyl radicals (•OH). Compared with conventional pure CeO2 abrasive particles, the material removal rate of the CeO2@ZSM-5 composite abrasive particle on silicon carbide is increased by 133%, and the surface roughness after polishing is reduced to 1.11 nm, realizing high-efficiency and high-quality polishing.

Description

Technical Field

[0001] This invention relates to a cerium oxide composite abrasive and its preparation method. Specifically, it relates to a CeO2@ZSM-5 composite abrasive used in the polishing process of silicon carbide wafers, belonging to the field of surface polishing technology. Background Technology

[0002] Silicon carbide (SiC) is a typical wide-bandgap semiconductor material with high hardness, high thermal conductivity, high breakdown electric field, and excellent chemical stability, making it promising for applications in power electronics, radio frequency devices, and high-temperature electronic devices. With the development of new energy vehicles, power electronics, and high-frequency communication technologies, the demand for high-quality SiC wafers is constantly increasing. Due to the high hardness and strong chemical inertness of SiC, its wafer surface processing is quite challenging. Traditional mechanical polishing methods easily produce scratches and subsurface damage on the material surface; therefore, chemical mechanical polishing (CMP) is usually used as the final surface processing technology.

[0003] In industrial-scale SiC chemical mechanical polishing, strong oxidants such as potassium permanganate (KMnO4) are typically added to the polishing slurry to achieve high material removal rates. However, these strong oxidants not only pollute the environment, but their reaction byproducts also increase the difficulty of subsequent cleaning.

[0004] Abrasive particles in the polishing slurry are a significant factor affecting material removal rate and surface quality. Cerium oxide, due to its Ce content... 3+ / Ce 4+ Redox pairs exhibit excellent performance in catalytic oxidation reactions, thus becoming potential abrasive materials for CMP (chemical mechanical polishing). However, pure CeO2 nanoparticles are prone to agglomeration, leading to a decrease in specific surface area and consequently reducing their catalytic activity and polishing efficiency. Therefore, developing a structurally stable, well-dispersed CeO2 composite abrasive with excellent catalytic performance is of great significance for achieving high SiC chemical mechanical polishing efficiency and surface quality. Summary of the Invention

[0005] This invention aims to solve the problem of low material removal rate during polishing with existing pure cerium oxide abrasives, and provides a CeO2@ZSM-5 composite abrasive, its preparation method, and its application. This invention uses hydrogen peroxide (H2O2) as the oxidant. In the CeO2@ZSM-5 composite abrasive, the ZSM-5 molecular sieve support, relying on its porous structure, can significantly improve the dispersibility of CeO2 and increase the number of active sites. Simultaneously, ZSM-5 participates in the decomposition reaction of H2O2 through its porous structure and acidic sites. Under the synergistic catalytic effect of CeO2 and ZSM-5, CeO2@ZSM-5 can efficiently catalyze the decomposition of H2O2 to generate a high concentration of •OH, thereby enhancing the catalytic decomposition ability of H2O2, promoting the generation of •OH, and further oxidizing the SiC surface, thus improving the material removal rate.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing CeO2@ZSM-5 composite abrasive particles, comprising the following steps: S01: Dissolve solid cerium nitrate hexahydrate in deionized water to form a cerium salt solution, add ZSM-5 molecular sieve powder to the cerium salt solution and stir to form a uniform mixed suspension, and then perform ultrasonic dispersion treatment on the mixed suspension; SO2: At room temperature, ammonia water is slowly added dropwise while continuously stirring, so that Ce... 3+ A precipitation reaction occurs on the surface of ZSM-5 to generate a cerium hydroxide precursor. The resulting mixture is mechanically stirred for 3 hours or more until the mixed solution turns yellow. S03: The obtained solid product was filtered and washed with anhydrous ethanol and deionized water. The washed solid was dried and calcined in a muffle furnace to obtain CeO2@ZSM-5 composite abrasive particles.

[0007] Furthermore, in step S01, the SiO2 / Al2O3 molar ratio of the commercial ZSM-5 molecular sieve is 38~40; the ultrasonication time is 2 h.

[0008] Furthermore, in step S01, the ammonia water used is 25 wt.% ammonia water.

[0009] Furthermore, in step S02, the solution pH is controlled at 9.5~10.5.

[0010] Furthermore, in step S03, the drying temperature is 70 ℃ and the drying time is 6 h; the calcination temperature is 450 ℃ and the calcination time is 5 h, and the calcination heating rate is 2 ℃ / min.

[0011] The present invention also provides a CeO2@ZSM-5 composite abrasive, which is obtained based on the preparation method described above.

[0012] The present invention also provides an application of CeO2@ZSM-5 composite abrasive, wherein a polishing slurry is prepared using the above-mentioned CeO2@ZSM-5 composite abrasive and applied to the chemical mechanical polishing of SiC wafers.

[0013] The present invention has the following beneficial effects: (1) A novel composite abrasive CeO2@ZSM-5 was prepared by ammonia precipitation using ZSM-5 molecular sieve as a carrier. After introducing ZSM-5 molecular sieve as a carrier, the dispersibility of CeO2 nanoparticles was significantly improved, effectively solving the problem of easy agglomeration and poor dispersibility of traditional industrial cerium oxide. This method has certain development prospects in the field of green polishing.

[0014] (2) The CeO2@ZSM-5 composite abrasive polishing slurry of the present invention is applied to the chemical mechanical polishing of silicon carbide wafers, which can effectively reduce the surface roughness of silicon carbide. Compared with conventional pure CeO2 abrasive, the polishing rate of CeO2@ZSM-5 composite abrasive is increased by 133%, and the surface roughness Sa value of silicon carbide after polishing is reduced to 1.11 nm.

[0015] (3) In this invention, ZSM-5 relies on its pore structure and acid sites to adsorb and enrich polar molecules such as H2O2, thereby increasing the local reactant concentration and accelerating the reaction rate. On the other hand, its Brønsted acid sites participate in the oxidation reaction of H2O2, and Lewis acid sites help to inhibit the aggregation of cerium species. CeO2@ZSM-5 constructs a synergistic catalytic mechanism of "CeO2 catalysis-pore confinement enrichment-molecular sieve acid activation", which can effectively catalyze the decomposition of H2O2 to generate high concentrations of highly oxidizing hydroxyl radicals (•OH), promote the formation of the oxide layer on the SiC surface, and achieve higher MRR in conjunction with the mechanical grinding effect of abrasive particles. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the mechanism of action of CeO2@ZSM-5 composite abrasives in the chemical mechanical polishing process of SiC; Figure 2 This is a scanning electron microscope image of the CeO2@ZSM-5 (CeO2 loading of 35%) composite abrasive particles in Example 1 of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0018] The present invention provides a method for preparing CeO2@ZSM-5 composite abrasive particles, comprising the following steps: S01: Dissolve solid cerium nitrate hexahydrate in deionized water to form a cerium salt solution. Add commercial ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 38~40 to the cerium salt solution and stir to form a uniform mixed suspension. Perform ultrasonic dispersion treatment on the mixed suspension for 2 hours. SO2: At room temperature, while continuously stirring, slowly add ammonia water to adjust the pH of the solution to 9.5-10.5, so that Ce... 3+ A precipitation reaction occurs on the ZSM-5 surface to generate a cerium hydroxide precursor. After the ammonia solution is added dropwise, the resulting mixture is mechanically stirred for 3 hours or more until the solution turns yellow. The ammonia solution used has a mass fraction of 25 wt.%. S03: The obtained solid product was filtered and washed with anhydrous ethanol and deionized water. The washed solid was dried at 70 °C for 6 h. The dried sample was calcined in a muffle furnace at 450 °C for 5 h (heating rate of 2 °C / min) to obtain CeO2@ZSM-5 composite abrasive particles.

[0019] A CeO2@ZSM-5 composite abrasive was prepared using the method described above.

[0020] An application of the CeO2@ZSM-5 composite abrasive of the present invention involves preparing a polishing slurry using the above CeO2@ZSM-5 composite abrasive. The solid content of the polishing slurry is 2.0 wt.%, and hydrogen peroxide is used as the oxidant. When applied to the chemical mechanical polishing of silicon carbide wafers, it can significantly improve the polishing rate and achieve a polishing precision superior to that of pure CeO2 abrasive, thus achieving a polishing effect of "high efficiency and high precision".

[0021] In this application, ZSM-5 utilizes its pore structure and acid sites to adsorb and enrich polar molecules such as H2O2, thereby increasing the local reactant concentration and accelerating the reaction rate. Furthermore, its Brønsted acid sites participate in the oxidation reaction of H2O2, while its Lewis acid sites help inhibit the aggregation of cerium species. CeO2@ZSM-5 constructs a synergistic catalytic mechanism of "CeO2 catalysis - pore-confined enrichment - molecular sieve acid activation," which can effectively catalyze the decomposition of H2O2 to generate high concentrations of highly oxidizing hydroxyl radicals (•OH), promoting the formation of an oxide layer on the SiC surface. Combined with the mechanical grinding effect of abrasive particles, this achieves a higher MRR (Mean Reduction Rate). Its polishing mechanism for SiC is as follows: Figure 1 As shown.

[0022] The preparation method of the present invention will be further described below with reference to the embodiments: Example 1

[0023] This embodiment provides a method for preparing CeO2@ZSM-5 composite abrasive particles. The CeO2@ZSM-5 composite abrasive particles are prepared by ammonia precipitation method, and the method steps are as follows: (1) Dissolve 4.454 g of solid cerium nitrate hexahydrate in 250 mL of deionized water to form a cerium salt solution. Add 10 g of commercial ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 38~40 to the cerium salt solution and stir to form a uniform mixed suspension. Then perform ultrasonic dispersion treatment for 2 hours.

[0024] (2) At room temperature, while continuously stirring, slowly add 25 wt.% ammonia water to adjust the pH of the solution to 9.5~10.5, so that Ce 3+ A precipitation reaction occurs on the ZSM-5 surface to generate cerium hydroxide precursor. After the ammonia solution is added dropwise, the resulting mixture is mechanically stirred for 3 hours or more until the solution turns yellow.

[0025] (3) The obtained solid product was filtered and washed three times each with anhydrous ethanol and deionized water. The washed solid was dried at 70 °C for 6 h. The dried sample was calcined in a muffle furnace at 450 °C for 5 h (heating rate of 2 °C / min) to obtain CeO2@ZSM-5 composite abrasive particles.

[0026] In this embodiment, CeO2@ZSM-5 composite abrasive particles with a CeO2 loading of 15% were finally obtained.

[0027] The polishing effect of the composite abrasive used in this embodiment to prepare a polishing slurry with a solid content of 2.0 wt.% on silicon carbide wafers is shown in Table 1. Example 2

[0028] This embodiment provides a method for preparing CeO2@ZSM-5 composite abrasive particles. The CeO2@ZSM-5 composite abrasive particles are prepared by ammonia precipitation method, and the method steps are as follows: (1) Dissolve 8.408 g of solid cerium nitrate hexahydrate in 250 mL of deionized water to form a cerium salt solution. Add 10 g of commercial ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 38~40 to the cerium salt solution and stir to form a uniform mixed suspension. Then perform ultrasonic dispersion treatment for 2 hours.

[0029] (2) At room temperature, while continuously stirring, slowly add 25 wt.% ammonia water to adjust the pH of the solution to 9.5~10.5, so that Ce 3+ A precipitation reaction occurs on the ZSM-5 surface to generate cerium hydroxide precursor. After the ammonia solution is added dropwise, the resulting mixture is mechanically stirred for 3 hours or more until the solution turns yellow.

[0030] (3) The obtained solid product was filtered and washed three times each with anhydrous ethanol and deionized water. The washed solid was dried at 70 °C for 6 h. The dried sample was calcined in a muffle furnace at 450 °C for 5 h (heating rate of 2 °C / min) to obtain CeO2@ZSM-5 composite abrasive particles.

[0031] In this embodiment, CeO2@ZSM-5 composite abrasive particles with a CeO2 loading of 25% were finally obtained.

[0032] The polishing effect of the composite abrasive used in this embodiment to prepare a polishing slurry with a solid content of 2.0 wt.% on silicon carbide wafers is shown in Table 1. Example 3

[0033] This embodiment provides a method for preparing CeO2@ZSM-5 composite abrasive particles. The CeO2@ZSM-5 composite abrasive particles are prepared by ammonia precipitation method, and the method steps are as follows: (1) Dissolve 13.584 g of solid cerium nitrate hexahydrate in 250 mL of deionized water to form a cerium salt solution. Add 10 g of commercial ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 38~40 to the cerium salt solution and stir to form a uniform mixed suspension. Then perform ultrasonic dispersion treatment for 2 hours.

[0034] (2) At room temperature, while continuously stirring, slowly add 25 wt.% ammonia water to adjust the pH of the solution to 9.5~10.5, so that Ce 3+ A precipitation reaction occurs on the ZSM-5 surface to generate cerium hydroxide precursor. After the ammonia solution is added dropwise, the resulting mixture is mechanically stirred for 3 hours or more until the solution turns yellow.

[0035] (3) The obtained solid product was filtered and washed three times each with anhydrous ethanol and deionized water. The washed solid was dried at 70 °C for 6 h. The dried sample was calcined in a muffle furnace at 450 °C for 5 h (heating rate of 2 °C / min) to obtain CeO2@ZSM-5 composite abrasive particles.

[0036] In this embodiment, CeO2@ZSM-5 composite abrasive particles with a CeO2 loading of 35% were finally obtained. A scanning electron microscope (SEM) schematic diagram is shown below. Figure 2 As shown.

[0037] The polishing effect of the composite abrasive used in this embodiment to prepare a polishing slurry with a solid content of 2.0 wt.% on silicon carbide wafers is shown in Table 1. Example 4

[0038] This embodiment provides a method for preparing CeO2@ZSM-5 composite abrasive particles. The CeO2@ZSM-5 composite abrasive particles are prepared by ammonia precipitation method, and the method steps are as follows: (1) Dissolve 16.819 g of solid cerium nitrate hexahydrate in 250 mL of deionized water to form a cerium salt solution. Add 10 g of commercial ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 38~40 to the cerium salt solution and stir to form a uniform mixed suspension. Then perform ultrasonic dispersion treatment for 2 hours.

[0039] (2) At room temperature, while continuously stirring, slowly add 25 wt.% ammonia water to adjust the pH of the solution to 9.5~10.5, so that Ce 3+ A precipitation reaction occurs on the ZSM-5 surface to generate cerium hydroxide precursor. After the ammonia solution is added dropwise, the resulting mixture is mechanically stirred for 3 hours or more until the solution turns yellow.

[0040] (3) The obtained solid product was filtered and washed three times each with anhydrous ethanol and deionized water. The washed solid was dried at 70 °C for 6 h. The dried sample was calcined in a muffle furnace at 450 °C for 5 h (heating rate of 2 °C / min) to obtain CeO2@ZSM-5 composite abrasive particles.

[0041] In this embodiment, CeO2@ZSM-5 composite abrasive particles with a CeO2 loading of 40% were finally obtained.

[0042] The polishing effect of the composite abrasive used in this embodiment to prepare a polishing slurry with a solid content of 2.0 wt.% on silicon carbide wafers is shown in Table 1. Example 5

[0043] This embodiment provides a method for preparing CeO2@ZSM-5 composite abrasive particles. The CeO2@ZSM-5 composite abrasive particles are prepared by ammonia precipitation method, and the method steps are as follows: (1) Dissolve 25.229 g of solid cerium nitrate hexahydrate in 250 mL of deionized water to form a cerium salt solution. Add 10 g of commercial ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 38~40 to the cerium salt solution and stir to form a uniform mixed suspension. Then perform ultrasonic dispersion treatment for 2 hours.

[0044] (2) At room temperature, while continuously stirring, slowly add 25 wt.% ammonia water to adjust the pH of the solution to 9.5~10.5, so that Ce 3+ A precipitation reaction occurs on the ZSM-5 surface to generate cerium hydroxide precursor. After the ammonia solution is added dropwise, the resulting mixture is mechanically stirred for 3 hours or more until the solution turns yellow.

[0045] (3) The obtained solid product was filtered and washed three times each with anhydrous ethanol and deionized water. The washed solid was dried at 70 °C for 6 h. The dried sample was calcined in a muffle furnace at 450 °C for 5 h (heating rate of 2 °C / min) to obtain CeO2@ZSM-5 composite abrasive particles.

[0046] In this embodiment, CeO2@ZSM-5 composite abrasive particles with a CeO2 loading of 50% were finally obtained.

[0047] The polishing effect of the composite abrasive used in this embodiment to prepare a polishing slurry with a solid content of 2.0 wt.% on silicon carbide wafers is shown in Table 1. Example 6

[0048] This embodiment provides a method for preparing CeO2@ZSM-5 composite abrasive particles. The CeO2@ZSM-5 composite abrasive particles are prepared by ammonia precipitation method, and the method steps are as follows: (1) Dissolve 37.843 g of solid cerium nitrate hexahydrate in 250 mL of deionized water to form a cerium salt solution. Add 10 g of commercial ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 38~40 to the cerium salt solution and stir to form a uniform mixed suspension. Then perform ultrasonic dispersion treatment for 2 hours.

[0049] (2) At room temperature, while continuously stirring, slowly add 25 wt.% ammonia water to adjust the pH of the solution to 9.5~10.5, so that Ce 3+ A precipitation reaction occurs on the ZSM-5 surface to generate cerium hydroxide precursor. After the ammonia solution is added dropwise, the resulting mixture is mechanically stirred for 3 hours or more until the solution turns yellow.

[0050] (3) The obtained solid product was filtered and washed three times each with anhydrous ethanol and deionized water. The washed solid was dried at 70 °C for 6 h. The dried sample was calcined in a muffle furnace at 450 °C for 5 h (heating rate of 2 °C / min) to obtain CeO2@ZSM-5 composite abrasive particles.

[0051] In this embodiment, CeO2@ZSM-5 composite abrasive particles with a CeO2 loading of 60% were finally obtained.

[0052] The polishing effect of the composite abrasive used in this embodiment to prepare a polishing slurry with a solid content of 2.0 wt.% on silicon carbide wafers is shown in Table 1. Comparative Example 1

[0053] In a comparative example, a method for preparing pure CeO2 abrasive grains includes the following steps: (1) Dissolve 37.843 g of cerium nitrate hexahydrate solid in 250 mL of deionized water to form a cerium salt solution, and then sonicate for 2 hours.

[0054] (2) At room temperature, while continuously stirring, slowly add 25 wt.% ammonia water to adjust the pH of the solution to 9.5~10.5, so that Ce 3+ A precipitation reaction occurs on the ZSM-5 surface to generate cerium hydroxide precursor. After the ammonia solution is added dropwise, the resulting mixture is mechanically stirred for 3 hours or more until the solution turns yellow.

[0055] (3) The obtained solid product was filtered and washed three times each with anhydrous ethanol and deionized water. The washed solid was dried at 70 °C for 6 h. The dried sample was calcined in a muffle furnace at 450 °C for 5 h (heating rate of 2 °C / min) to obtain CeO2 abrasive particles.

[0056] In this comparative example, pure CeO2 abrasive solids were finally obtained.

[0057] The polishing effect of a polishing slurry with a solid content of 2.0 wt.% prepared using the comparative abrasive particles on silicon carbide wafers is shown in Table 1. Comparative Example 2

[0058] In the comparative example, the pure commercial ZSM-5 abrasive grains had a SiO2 / Al2O3 molar ratio of 38~40.

[0059] The polishing effect of a polishing slurry with a solid content of 2.0 wt.% prepared using the comparative abrasive particles on silicon carbide wafers is shown in Table 1.

[0060] Polishing tests were conducted on silicon carbide wafers using the polishing slurries of Examples 1-6 and Comparative Examples 1-2 under certain polishing conditions.

[0061] The preparation conditions for the polishing slurry are as follows: Abrasive content: 2.0 wt.%; H2O2 content: 7 wt.% Polishing solution pH: 5; The polishing conditions for the polishing test are as follows: Polishing machine: UNIPOL-1502 single-sided polishing machine; Workpiece: 2-inch diameter 4H-SiC(0001) surface; Polishing pad: Suba 800 polyurethane polishing pad; Polishing pressure: 6 kg; Lower chassis speed: 70 rpm; Polishing time: 1 hour.

[0062] After polishing, the silicon carbide wafer is washed and dried in the order of acetone, ethanol, and deionized water. The mass of the silicon carbide wafer before and after polishing is measured using a precision analytical balance, according to the formula... The material removal rate (MRR) was calculated. Additionally, the surface roughness (Sa) of silicon carbide before and after polishing was measured using a Sneox 090 3D surface profilometer, with a vertical resolution of 0.1 nm, a maximum lateral resolution of 0.14 nm, an order accuracy of 0.5%, and a measurement area of ​​500 μm × 500 μm.

[0063] The polishing effects of the polishing slurries on silicon carbide wafers in each embodiment are shown in Table 1. Table 1 shows that ZSM-5 itself has a relatively small impact on the material removal rate in Comparative Example 2. The material removal rate (MRR) of the CeO2@ZSM-5 composite abrasives prepared in Examples 2-6 is higher than that of pure CeO2 abrasives. Compared with pure CeO2 abrasives, the surface roughness (Sa) of the samples obtained in Examples 1-6 is reduced. In Example 4, when the CeO2 loading is 40%, the obtained CeO2@ZSM-5 composite abrasive exhibits the best polishing performance, with a material removal rate 133% higher than that of pure CeO2 abrasives, while the surface roughness decreases from 11.91 nm to 1.11 nm.

[0064] Table 1. Polishing effect of abrasive particles on silicon carbide wafers in various embodiments and comparative examples of the present invention. Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 <![CDATA[CeO2 loading (%)]]> 15 25 35 40 50 60 100 0 MRR (μm / h) 191 286 334 446 382 255 191 159 Sa(nm) 7.37 6.03 2.21 1.11 3.35 5.80 10.51 11.91 In summary, compared with pure CeO2 and ZSM-5 abrasives, the CeO2@ZSM-5 composite abrasives prepared in this invention can significantly improve the material removal rate and reduce the surface roughness during silicon carbide wafer polishing. The introduction of the ZSM-5 molecular sieve support improves the dispersibility of CeO2, and the synergistic catalytic effect of ZSM-5 and CeO2 enhances the catalytic decomposition ability of H2O2, thereby promoting the synergistic action of chemical and mechanical processes and achieving efficient and green chemical mechanical polishing.

[0065] In this application, ZSM-5 molecular sieve is a silica-alumina molecular sieve material with a regular pore structure, possessing a high specific surface area and good structural stability, making it suitable as a carrier material for active components. Loading CeO2 nanoparticles onto the surface of ZSM-5 to form a composite structure not only effectively inhibits CeO2 particle aggregation, improving its dispersibility and catalytic activity, but also utilizes the pore aggregation effect of ZSM-5 itself and the acidic sites to catalyze the generation of the active oxygen species •OH, thereby enhancing CMP polishing performance.

[0066] The above description is merely a preferred embodiment of the present invention. The embodiments are not intended to limit the scope of patent protection of the present invention. Therefore, any equivalent structural changes made based on the description and drawings of the present invention should also be included within the scope of protection of the appended claims.

Claims

1. A method for preparing CeO2@ZSM-5 composite abrasive particles, characterized in that, Includes the following steps: S01: Dissolve solid cerium nitrate hexahydrate in deionized water to form a cerium salt solution, add ZSM-5 molecular sieve powder to the cerium salt solution and stir to form a uniform mixed suspension, and then perform ultrasonic dispersion treatment on the mixed suspension; SO2: At room temperature, ammonia water is added dropwise while continuously stirring, so that Ce... 3+ A precipitation reaction occurs on the surface of ZSM-5 to generate a cerium hydroxide precursor. The resulting mixture is mechanically stirred for 3 hours or more until the mixed solution turns yellow. S03: The obtained solid product was filtered and washed with anhydrous ethanol and deionized water. The washed solid was dried and then calcined to obtain CeO2@ZSM-5 composite abrasive particles.

2. The method for preparing CeO2@ZSM-5 composite abrasive particles according to claim 1, characterized in that, In step S01, the molar ratio of SiO2 / Al2O3 in the ZSM-5 molecular sieve is 38~40; the ultrasonication time is 2 h.

3. The method for preparing CeO2@ZSM-5 composite abrasive particles according to claim 1, characterized in that, In step S02, the ammonia solution used is 25 wt.% ammonia solution.

4. The method for preparing CeO2@ZSM-5 composite abrasive particles according to claim 1, characterized in that, In step S02, the pH of the solution is controlled at 9.5~10.

5.

5. The method for preparing CeO2@ZSM-5 composite abrasive particles according to claim 1, characterized in that, In step S03, the drying temperature is 70 ℃ and the drying time is 6 h; the calcination temperature is 450 ℃ and the calcination time is 5 h, with a heating rate of 2 ℃ / min.

6. A CeO2@ZSM-5 composite abrasive, characterized in that, Prepared according to the preparation method described in any one of claims 1-5.

7. An application of CeO2@ZSM-5 composite abrasive, characterized in that, The CeO2@ZSM-5 composite abrasive particles described in claim 6 are prepared into a chemical mechanical polishing slurry and applied to the polishing process of silicon carbide wafers.

Images