Solid acid modified ceria abrasive particles, methods of making the same, and use in polishing liquids
By forming a solid acid structure on the surface of cerium oxide, its chemical corrosion effect on silicon oxide is enhanced, solving the problem that traditional cerium oxide abrasives cannot simultaneously meet the requirements of high removal rate and low surface roughness, and achieving efficient silicon oxide film planarization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUANGPU INST OF MATERIALS
- Filing Date
- 2026-01-22
- Publication Date
- 2026-05-29
AI Technical Summary
Cerium oxide abrasive particles prepared by traditional calcination methods cannot simultaneously meet the requirements of advanced processes for high removal rates and low surface roughness, and cannot effectively meet the planarization requirements of high aspect ratio features of device structures such as fin field-effect transistors and gate-all-around devices.
By immersing cerium oxide particles in a sulfur-containing precursor solution, the precursor is adsorbed onto the cerium oxide surface. Then, calcination is performed to form a solid acid structure, which alters the electronic structure of cerium oxide, promotes the formation of Ce-O-Si bonds between silicon oxide and modified cerium oxide, enhances chemical corrosion, increases the removal rate of the silicon oxide film, and reduces surface roughness.
The modified cerium oxide abrasive significantly improved the removal rate of silicon oxide film and reduced the surface roughness after polishing, meeting the high-efficiency planarization requirements of advanced processes.
Smart Images
Figure CN122104148A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of chemical mechanical polishing abrasives and polishing fluids, specifically relating to a method for preparing modified cerium oxide abrasives and polishing fluids. Background Technology
[0002] Chemical mechanical polishing (CMP) is one of the core processes in integrated circuit manufacturing. Through the synergistic effect of chemical etching and mechanical polishing, it achieves nanoscale global planarization of the wafer surface, providing a smooth surface for subsequent photolithography, etching, and other processes, thereby ensuring the high performance and high reliability of integrated circuits. Slurry is one of the most important CMP materials, accounting for approximately 49% of the total cost of CMP materials. The main components of slurry include abrasive grains, surfactants, and pH adjusters. Cerium oxide abrasive grains are among the most commonly used abrasive grains in integrated circuit manufacturing.
[0003] Cerium element exists in cerium oxide abrasive grains. 3+ and Ce 4+ The presence of two valence states, and the interconversion between these states, endows cerium oxide abrasives with strong reactivity. During polishing with silicon oxide materials, cerium oxide abrasives can form Ce—O—Si bonds with silicon oxide, generating easily removable "chemical teeth," thus significantly improving the removal rate of silicon oxide. Based on these properties, cerium oxide abrasives are used for planarization of shallow trench isolation (STI) and interlayer dielectric (ILD) in chip manufacturing processes. In mature processes, cerium oxide prepared by calcination is typically used as the polishing abrasive. Advanced processes place higher demands on CMP. Device structures such as FinFETs and gate-all-around (GAA) have high aspect ratios, requiring thicker planarization layers and faster silicon oxide removal rates to improve production efficiency, while also demanding lower surface roughness. Cerium oxide abrasives prepared by traditional calcination methods can no longer simultaneously meet the requirements of high removal rates and low surface roughness in advanced processes; therefore, the development of novel modified cerium oxide abrasives is essential. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a modification method for preparing cerium oxide as a solid acid, thereby improving the removal rate of silicon oxide by cerium oxide and reducing surface roughness, and using the modified cerium oxide as abrasive particles to formulate a polishing slurry.
[0005] To achieve the above objectives, this invention involves immersing cerium oxide particles in a sulfur-containing precursor solution, allowing the precursor to fully adsorb onto the cerium oxide surface. Then, calcination causes the sulfur in the precursor to coordinate with cerium oxide, forming a solid acid structure. This modified cerium oxide alters its electronic structure. During contact between silicon oxide and the modified cerium oxide, it promotes the dehydration of Si-OH groups in silicon oxide and the formation of Ce-O-Si bonds with cerium oxide, thereby enhancing the chemical corrosion effect of cerium oxide on the silicon oxide film and increasing the removal rate of the silicon oxide film by the cerium oxide abrasive particles. The formation of Ce-O-Si bonds through frictional contact between cerium oxide abrasive particles and silicon oxide requires a certain amount of time. The enhanced chemical corrosion effect of the modified cerium oxide in this invention accelerates the formation of a softening layer on the silicon oxide surface during polishing, which helps reduce the surface roughness after polishing.
[0006] The technical solution of the present invention is as follows:
[0007] A method for preparing solid acid-modified cerium oxide abrasive grains includes the following steps:
[0008] (1) Immerse cerium oxide particles in a sulfur-containing precursor solution. After the sulfur-containing precursor is fully adsorbed on the surface of cerium oxide particles, separate the cerium oxide particles.
[0009] (2) The separated cerium oxide particles are dried to remove most of the solvent, and then cerium oxide powder is obtained by crushing. The cerium oxide powder is then calcined to form a solid acid structure to obtain solid acid modified cerium oxide abrasive particles.
[0010] The sulfur-containing precursor is one or more of the following: sulfur-containing inorganic salts, sulfur-containing inorganic acids, thiols, thiophenols, mercapto compounds, and sulfur-containing heterocycles.
[0011] The sulfur-containing precursors can be inorganic salts, such as sulfates, persulfates, and sulfites, or inorganic acids, such as sulfuric acid, persulfate, and sulfite. They can also be small molecules such as thiols, thiophenols, mercapto compounds, and sulfur-containing heterocycles, resulting in a wider variety of precursors.
[0012] Preferably, the sulfur-containing precursor in step (1) is one or more of sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, ammonium sulfate, potassium persulfate, sodium persulfate, ammonium persulfate, sulfuric acid, sodium sulfite, potassium sulfite, ammonium sulfite, 1-propanethiol, 1-butanethiol, dodecanethiol, thiophene, p-toluenethiophenol, 2-thiobenzimidazole, thiosalicylic acid, thiophene, thiazole, thiaran, and thiazide.
[0013] Preferably, the solvent of the sulfur-containing precursor solution in step (1) is one or more of water, methanol, ethanol, isopropanol, n-propanol, butanol, toluene, xylene, ethyl acetate, acetone, petroleum ether, dimethyl sulfoxide, N,N-dimethylformamide, dichloromethane, and chloroform.
[0014] Preferably, the mass ratio of cerium oxide particles to sulfur-containing precursor in step (1) is 1:(0.05-5), and more preferably the mass ratio is 1:(0.1-1).
[0015] Preferably, in step (1), the average particle size of the cerium oxide particles is 20-1000 nm; and the concentration of the sulfur-containing precursor solution is 0.1-50%.
[0016] Preferably, in step (1), the average particle size of the cerium oxide particles is 30-300 nm; and the concentration of the sulfur-containing precursor solution is 1-10%.
[0017] Preferably, the soaking time in step (1) is 1-72 h, and the calcination temperature in step (2) is 300-900 ℃, and the calcination time is 1-24 h.
[0018] Preferably, the soaking time in step (1) is 3-10 h, the calcination temperature in step (2) is 400-700 ℃, and the calcination time is 3-6 h; the calcination atmosphere in step (2) is one or more of nitrogen, argon, oxygen and air.
[0019] Preferably, the separation method in step (1) is one or more of centrifugation, filtration and natural sedimentation.
[0020] Preferably, the drying method in step (2) is one or more of natural air drying, hot air drying, freeze drying and vacuum drying.
[0021] The solid acid-modified cerium oxide abrasive particles prepared by the above method are mechanically dispersed to obtain a modified cerium oxide dispersion, which can be used to formulate modified cerium oxide polishing slurries. Preferably, the mechanical dispersion method is one or more of ball milling, sand milling, high-pressure nanofluidization, and mechanical stirring.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] (1) The solid acid modified cerium oxide of the present invention has a stronger chemical effect on the silicon oxide film, and the removal rate of the silicon oxide film obtained by using modified cerium oxide as abrasive polishing is faster.
[0024] (2) The calcination temperature used in this invention is relatively low, so the particle size of the modified cerium oxide particles prepared will not increase significantly. The modification process of cerium oxide particles will not significantly change their morphological characteristics. After the modified cerium oxide particles are used to prepare a polishing liquid for polishing silicon oxide film, the surface roughness is lower. Attached Figure Description
[0025] Figure 1 The particle size distribution diagram is shown for the modified cerium oxide obtained in Example 1.
[0026] Figure 2 This is a SEM image of the modified cerium oxide obtained in Example 1.
[0027] Figure 3 The particle size distribution diagram of the modified cerium oxide obtained in Example 2 is shown.
[0028] Figure 4 This is a SEM image of the modified cerium oxide obtained in Example 2.
[0029] Figure 5 The particle size distribution diagram is shown for the modified cerium oxide obtained in Example 3.
[0030] Figure 6 This is a SEM image of the modified cerium oxide obtained in Example 3.
[0031] Figure 7 The particle size distribution diagram is shown for the modified cerium oxide obtained in Example 4.
[0032] Figure 8 This is a SEM image of the modified cerium oxide obtained in Example 4.
[0033] Figure 9 The particle size distribution diagram is shown for the modified cerium oxide obtained in Example 5.
[0034] Figure 10 This is a SEM image of the modified cerium oxide obtained in Example 5.
[0035] Figure 11 The particle size distribution diagram is shown for the modified cerium oxide obtained in Comparative Example 1.
[0036] Figure 12 The image shows the SEM image of the modified cerium oxide obtained in Comparative Example 1.
[0037] Figure 13 The particle size distribution diagram of the modified cerium oxide obtained in Comparative Example 2 is shown.
[0038] Figure 14 The image shows the SEM image of the modified cerium oxide obtained in Comparative Example 2.
[0039] Figure 15 The particle size distribution diagram is shown for the modified cerium oxide obtained in Comparative Example 3.
[0040] Figure 16 The image shows the SEM image of the modified cerium oxide obtained in Comparative Example 3.
[0041] Figure 17 The particle size distribution diagram is shown for the modified cerium oxide obtained in Comparative Example 4.
[0042] Figure 18 The image shows the SEM image of the modified cerium oxide obtained in Comparative Example 4.
[0043] Figure 19 The particle size distribution diagram is shown for the modified cerium oxide obtained in Comparative Example 5.
[0044] Figure 20 The image shows the SEM image of the modified cerium oxide obtained in Comparative Example 5. Detailed Implementation
[0045] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.
[0046] Example 1
[0047] (1) Prepare a 10% potassium sulfate aqueous solution, add cerium oxide particles to the solution for soaking, wherein the average particle size of cerium oxide particles is 182 nm, the mass ratio of cerium oxide to potassium sulfate aqueous solution is 1:10, the soaking time is 5 h, and after soaking, the cerium oxide particles are separated from the precursor solution by centrifugation.
[0048] (2) The cerium oxide separated from the precursor solution was first dried with hot air to remove most of the solvent, and then mechanically pulverized to obtain cerium oxide powder. The obtained cerium oxide powder was calcined to obtain solid acid-modified cerium oxide particles, wherein the calcination temperature was 400 °C, the calcination atmosphere was nitrogen, and the calcination time was 3 h.
[0049] (3) The obtained solid acid-modified cerium oxide particles are dispersed by ball milling to obtain modified cerium oxide dispersion, which can be used for the preparation of modified cerium oxide polishing liquid. Figure 1 This shows the particle size distribution of the solid acid-modified cerium oxide obtained in this embodiment. Figure 2 This is a SEM image of the solid acid-modified cerium oxide obtained in this embodiment.
[0050] Example 2
[0051] (1) Prepare a 5% sodium sulfate aqueous solution, add cerium oxide particles to the solution for soaking, wherein the average particle size of cerium oxide particles is 47 nm, the mass ratio of cerium oxide to sodium sulfate aqueous solution is 1:20, the soaking time is 8 h, and after soaking, the cerium oxide particles are separated from the precursor solution by centrifugation.
[0052] (2) The cerium oxide separated from the precursor solution was first dried under reduced pressure to remove most of the solvent, and then mechanically pulverized to obtain cerium oxide powder. The obtained cerium oxide powder was calcined to obtain solid acid-modified cerium oxide particles, wherein the calcination temperature was 600 °C, the calcination atmosphere was argon, and the calcination time was 5 h.
[0053] (3) The obtained solid acid-modified cerium oxide particles are dispersed by high pressure nanofluidization to obtain modified cerium oxide dispersion, which can be used for the preparation of modified cerium oxide polishing liquid. Figure 3 This shows the particle size distribution of the solid acid-modified cerium oxide obtained in this embodiment. Figure 4 This is a SEM image of the solid acid-modified cerium oxide obtained in this embodiment.
[0054] Example 3
[0055] (1) Prepare a 3% potassium persulfate aqueous solution, add cerium oxide particles to the solution for soaking, wherein the average particle size of cerium oxide particles is 228 nm, the mass ratio of cerium oxide to potassium persulfate aqueous solution is 1:5, the soaking time is 10 h, and after soaking, the cerium oxide particles are separated from the precursor solution by natural sedimentation.
[0056] (2) The cerium oxide separated from the precursor solution was first dried with hot air to remove most of the solvent, and then mechanically pulverized to obtain cerium oxide powder. The obtained cerium oxide powder was calcined to obtain solid acid-modified cerium oxide particles, wherein the calcination temperature was 500 °C, the calcination atmosphere was oxygen, and the calcination time was 6 h.
[0057] (3) The obtained solid acid-modified cerium oxide particles are dispersed by sand milling to obtain modified cerium oxide dispersion, which can be used for the preparation of modified cerium oxide polishing liquid. Figure 5 This shows the particle size distribution of the solid acid-modified cerium oxide obtained in this embodiment. Figure 6 This is a SEM image of the solid acid-modified cerium oxide obtained in this embodiment.
[0058] Example 4
[0059] (1) Prepare a 6% ammonium sulfate aqueous solution, add cerium oxide particles to the solution for soaking, wherein the average particle size of cerium oxide particles is 224 nm, the mass ratio of cerium oxide to ammonium sulfate aqueous solution is 1:6, the soaking time is 4 h, and after soaking, the cerium oxide particles are separated from the precursor solution by filtration.
[0060] (2) The cerium oxide separated from the precursor solution was first dried under reduced pressure to remove most of the solvent, and then mechanically pulverized to obtain cerium oxide powder. The obtained cerium oxide powder was calcined to obtain solid acid-modified cerium oxide particles, wherein the calcination temperature was 700 °C, the calcination atmosphere was nitrogen, and the calcination time was 4 h.
[0061] (3) The obtained solid acid-modified cerium oxide particles are dispersed by sand milling to obtain modified cerium oxide dispersion, which can be used for the preparation of modified cerium oxide polishing liquid. Figure 7 This shows the particle size distribution of the solid acid-modified cerium oxide obtained in this embodiment. Figure 8This is a SEM image of the solid acid-modified cerium oxide obtained in this embodiment.
[0062] Example 5
[0063] (1) Prepare a 1% ethanol solution of dodecanethiol, add cerium oxide particles to the solution for soaking, wherein the average particle size of cerium oxide particles is 180 nm, the mass ratio of cerium oxide to ethanol solution of dodecanethiol is 1:10, the soaking time is 9h, and after soaking, the cerium oxide particles are separated from the precursor solution by centrifugation.
[0064] (2) The cerium oxide separated from the precursor solution was first dried with hot air to remove most of the solvent, and then mechanically pulverized to obtain cerium oxide powder. The obtained cerium oxide powder was calcined to obtain solid acid-modified cerium oxide particles, wherein the calcination temperature was 400 °C, the calcination atmosphere was argon, and the calcination time was 6 h.
[0065] (3) The obtained solid acid-modified cerium oxide particles are dispersed by ball milling to obtain modified cerium oxide dispersion, which can be used for the preparation of modified cerium oxide polishing liquid. Figure 9 This shows the particle size distribution of the solid acid-modified cerium oxide obtained in this embodiment. Figure 10 This is a SEM image of the solid acid-modified cerium oxide obtained in this embodiment.
[0066] Example 6
[0067] (1) Prepare a 2% methanol solution of thiophenol, add cerium oxide particles to the solution for soaking, wherein the average particle size of cerium oxide particles is 32 nm, the mass ratio of cerium oxide to methanol solution of thiophenol is 1:5, the soaking time is 24 h, and after soaking, the cerium oxide particles are separated from the precursor solution by centrifugation.
[0068] (2) The cerium oxide separated from the precursor solution was first freeze-dried to remove most of the solvent, and then mechanically pulverized to obtain cerium oxide powder. The obtained cerium oxide powder was calcined to obtain solid acid-modified cerium oxide particles, wherein the calcination temperature was 900 °C, the calcination atmosphere was air, and the calcination time was 3 h.
[0069] (3) The obtained solid acid-modified cerium oxide particles are dispersed by high pressure nanofluidization to obtain modified cerium oxide dispersion, which can be used for the preparation of modified cerium oxide polishing liquid.
[0070] Example 7
[0071] (1) Prepare a 1% toluene solution of thiophene, add cerium oxide particles to the solution for soaking, wherein the average particle size of cerium oxide particles is 386 nm, the mass ratio of cerium oxide to toluene solution of thiophene is 1:7, the soaking time is 6 h, and after soaking, the cerium oxide particles are separated from the precursor solution by natural sedimentation.
[0072] (2) The cerium oxide separated from the precursor solution was first air-dried to remove most of the solvent, and then mechanically pulverized to obtain cerium oxide powder. The obtained cerium oxide powder was calcined to obtain solid acid-modified cerium oxide particles, wherein the calcination temperature was 800 °C, the calcination atmosphere was oxygen, and the calcination time was 8 h.
[0073] (3) The obtained solid acid-modified cerium oxide particles are dispersed by high pressure nanofluidization to obtain modified cerium oxide dispersion, which can be used for the preparation of modified cerium oxide polishing liquid.
[0074] Comparative Example 1
[0075] (1) Cerium oxide particles were added to pure water for soaking. The average particle size of the cerium oxide particles was 182 nm, the mass ratio of cerium oxide to water was 1:10, and the soaking time was 5 h. After soaking, the cerium oxide particles were separated from the soaking solution by centrifugation.
[0076] (2) The cerium oxide separated from the soaking solution was first dried with hot air to remove most of the solvent, and then mechanically crushed to obtain cerium oxide powder. The obtained cerium oxide powder was calcined at a temperature of 400 °C in a nitrogen atmosphere for 3 h.
[0077] (3) The modified cerium oxide particles obtained after calcination are dispersed by ball milling to obtain a modified cerium oxide dispersion, which can be used to prepare a modified cerium oxide polishing solution. Figure 11 This shows the particle size distribution of the modified cerium oxide obtained in this embodiment. Figure 12 This is a SEM image of the modified cerium oxide obtained in this embodiment.
[0078] Comparative Example 2
[0079] (1) Cerium oxide particles were added to pure water for soaking. The average particle size of the cerium oxide particles was 47 nm, the mass ratio of cerium oxide to water was 1:20, and the soaking time was 8 h. After soaking, the cerium oxide particles were separated from the soaking solution by centrifugation.
[0080] (2) The cerium oxide separated from the soaking solution was first dried under reduced pressure to remove most of the solvent, and then mechanically pulverized to obtain cerium oxide powder. The obtained cerium oxide powder was calcined at a temperature of 600 °C in an argon atmosphere for 5 h.
[0081] (3) The modified cerium oxide particles obtained after calcination are dispersed by high pressure nanofluidization to obtain a modified cerium oxide dispersion, which can be used to prepare a modified cerium oxide polishing solution. Figure 13 This shows the particle size distribution of the modified cerium oxide obtained in this embodiment. Figure 14 This is a SEM image of the modified cerium oxide obtained in this embodiment.
[0082] Comparative Example 3
[0083] (1) Cerium oxide particles were added to pure water for soaking. The average particle size of the cerium oxide particles was 228 nm, the mass ratio of cerium oxide to water was 1:5, the soaking time was 10 h, and the cerium oxide particles were separated from the soaking solution by natural sedimentation after soaking.
[0084] (2) The cerium oxide separated from the soaking solution was first dried with hot air to remove most of the solvent, and then mechanically crushed to obtain cerium oxide powder. The obtained cerium oxide powder was calcined at a temperature of 500 °C in an oxygen atmosphere for 6 h.
[0085] (3) The modified cerium oxide particles obtained after calcination are dispersed by sand milling to obtain a modified cerium oxide dispersion, which can be used to prepare a modified cerium oxide polishing solution. Figure 15 This shows the particle size distribution of the modified cerium oxide obtained in this embodiment. Figure 16 This is a SEM image of the modified cerium oxide obtained in this embodiment.
[0086] Comparative Example 4
[0087] (1) Cerium oxide particles and ammonium sulfate particles were mixed by dry ball milling, wherein the average particle size of cerium oxide particles was 224 nm, the mass ratio of cerium oxide to ammonium sulfate was 1:0.36, the dry ball milling time was 1 h, and the ball milling speed was 400 rpm.
[0088] (2) The mixture after ball milling is mechanically crushed to obtain mixed powder, and then the powder is calcined at a temperature of 700 °C, in a nitrogen atmosphere, for a time of 4 h.
[0089] (3) Modified cerium oxide particles are obtained and dispersed by sand milling to obtain modified cerium oxide dispersion, which can be used for the preparation of modified cerium oxide polishing liquid. Figure 17 This shows the particle size distribution of the solid acid-modified cerium oxide obtained in this embodiment. Figure 18 This is a SEM image of the solid acid-modified cerium oxide obtained in this embodiment.
[0090] Comparative Example 5
[0091] (1) Prepare a 1% ethanol solution of dodecanethiol, add cerium oxide particles to the solution for soaking, wherein the average particle size of cerium oxide particles is 180 nm, the mass ratio of cerium oxide to ethanol solution of dodecanethiol is 1:10, the soaking time is 9h, and after soaking, the cerium oxide particles are separated from the precursor solution by centrifugation.
[0092] (2) The cerium oxide separated from the precursor solution was first dried with hot air to remove most of the solvent, and then mechanically pulverized to obtain cerium oxide powder. The obtained cerium oxide powder was placed in a muffle furnace, nitrogen gas was introduced at room temperature, and it was allowed to stand for 6 h.
[0093] (3) Cerium oxide particles are obtained and modified cerium oxide dispersion is obtained by sand milling, which can be used for the preparation of modified cerium oxide polishing liquid. Figure 19 This shows the particle size distribution of the modified cerium oxide obtained in this embodiment. Figure 20 This is a SEM image of the modified cerium oxide obtained in this embodiment.
[0094] The modified or unmodified cerium oxide used in the above examples and comparative examples was used as the abrasive to prepare a polishing slurry (all parameters were kept consistent except for the cerium oxide particles), which was then used to polish the silica film. The polishing slurry composition was as follows: 1% cerium oxide, 0.3% polyacrylic acid, 0.01% sodium dodecylbenzenesulfonate, 0.1% ethylene glycol, and 98.59% water. All polishing slurries were tested under the same conditions: the grinding disc and die head speeds were 93 and 87 rpm, respectively; the polishing slurry flow rate was 200 mL / min; and the polishing time was 1 min. The surface roughness obtained by polishing the silica film at the removal rate is shown in Table 1.
[0095] Table 1. Comparison of the effects of different cerium oxides as abrasive polishing silicon oxide films.
[0096]
[0097] Compared to Comparative Examples 1-3, Examples 1-3 incorporated sulfur-containing precursors that could form solid acid structures, resulting in higher silica removal rates and lower surface roughness. Comparative Example 4 used a dry mixing method, leading to minimal adsorption of sulfur-containing precursors onto the cerium oxide surface, resulting in a lower amount of solid acid structures formed during subsequent calcination. Therefore, compared to Example 4, it had a lower removal rate and higher surface roughness. Comparative Example 5, unlike Example 5, did not undergo high-temperature calcination, thus failing to form solid acid structures, resulting in an even lower removal rate and higher surface roughness.
[0098] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for preparing solid acid-modified cerium oxide abrasive particles, characterized in that, Includes the following steps: (1) Immerse cerium oxide particles in a sulfur-containing precursor solution. After the sulfur-containing precursor is fully adsorbed on the surface of cerium oxide particles, separate the cerium oxide particles. (2) The separated cerium oxide particles are dried and crushed to obtain cerium oxide powder. The cerium oxide powder is then calcined to form a solid acid structure to obtain solid acid modified cerium oxide abrasive particles. The sulfur-containing precursor is one or more of the following: sulfur-containing inorganic salt, sulfur-containing inorganic acid, thiol, thiophenol, mercapto compound, and sulfur-containing heterocycle.
2. The preparation method according to claim 1, characterized in that, The sulfur-containing precursor mentioned in step (1) is one or more of the following: sulfate, persulfate, sulfite, sulfuric acid, persulfate, sulfurous acid, 1-propanethiol, 1-butanethiol, dodecylthiol, thiophene, p-toluenethiophenol, 2-thiobenzimidazole, thiosalicylic acid, thiophene, thiazole, thiaran, and thiazide.
3. The preparation method according to claim 2, characterized in that, The sulfur-containing precursor mentioned in step (1) is one or more of sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, ammonium sulfate, potassium persulfate, sodium persulfate, ammonium persulfate, sodium sulfite, potassium sulfite, and ammonium sulfite; the solvent of the sulfur-containing precursor solution is one or more of water, methanol, ethanol, isopropanol, n-propanol, butanol, toluene, xylene, ethyl acetate, acetone, petroleum ether, dimethyl sulfoxide, N,N-dimethylformamide, dichloromethane, and chloroform.
4. The preparation method according to claim 1, 2, or 3, characterized in that, In step (1), the mass ratio of cerium oxide particles to sulfur-containing precursor is 1:(0.05-5), and a more preferred mass ratio is 1:(0.1-1).
5. The preparation method according to claim 4, characterized in that, In step (1), the average particle size of cerium oxide particles is 20-1000 nm; the concentration of the sulfur-containing precursor solution is 0.1-50%.
6. The preparation method according to claim 5, characterized in that, In step (1), the average particle size of cerium oxide particles is 30-300 nm; the concentration of the sulfur-containing precursor solution is 1-10%.
7. The preparation method according to claim 1, 2, or 3, characterized in that, The soaking time in step (1) is 1-72 h, and the calcination temperature in step (2) is 300-900 ℃, and the calcination time is 1-24 h.
8. The preparation method according to claim 7, characterized in that, The soaking time in step (1) is 3-10 h, the calcination temperature in step (2) is 400-700 ℃, and the calcination time is 3-6 h; the calcination atmosphere in step (2) is one or more of nitrogen, argon, oxygen and air.
9. Solid acid-modified cerium oxide abrasive grains prepared by the method according to any one of claims 1-8.
10. The application of the solid acid-modified cerium oxide abrasive particles according to claim 9 in polishing fluid.