Cerium oxide polishing solution

Abstract

The invention discloses a cerium oxide polishing solution. The cerium oxide polishing solution comprises the following components in percentage by mass: 0.1%-10% of cerium oxide grinding particles, 0.1%-5% of a polishing inhibitor, 0.01%-5% of a dispersing agent, 0.01%-2% of a pH regulator, 50-500 ppm of an anionic surfactant and water. According to the cerium oxide polishing solution, the removal rate of the polishing solution can be controlled and regulated, and the loss of trench oxides is reduced; compared with a silicon nitride film, the silicon nitride film can selectively remove the silicon oxide film, and has a good application prospect. The method has the advantages that the silicon oxide film can be selectively removed, the removal rate of SiO2 can be reduced, and the dishing amount of the groove part in a 100 mu m / 100 mu m area can be reduced.

Description

Technical Field

[0001] The present invention relates to a cerium oxide polishing liquid. Background Art

[0002] With the continuous development of the integration density of integrated circuits, shallow trench isolation (STI) technology has been widely used in the field of integrated circuit manufacturing. The STI structure plays a role in device isolation in high-density transistors, and STI technology has become the mainstream isolation technology in the past decade. Chemical mechanical polishing (CMP), as the only means of global or local planarization in integrated circuit manufacturing, is an important step in the manufacturing process of the STI structure. During the manufacturing process of the STI structure, trenches are created on the Si substrate around active devices and filled with SiO2 dielectric. When filling SiO2, SiO2 is also deposited in areas where the wafer is not needed, and the excess SiO2 needs to be removed using CMP technology. At the same time, in order to prevent damage to the important epitaxial layer on the Si substrate during the CMP process, a Si3N4 stop layer needs to be grown under the SiO2 deposition layer. Therefore, it is crucial to minimize the removal rate of Si3N4 under the premise of a relatively high SiO2 removal rate. The removal of SiO2 dielectric by SiO2 sol polishing relies only on mechanical action, and the removal rate of SiO2 dielectric is relatively low, resulting in too low a selectivity ratio of the removal rates of SiO2 and Si3N4.

[0003] Currently, the research on the removal rate selectivity ratio of STI CMP mainly focuses on suppressing the removal rate of Si3N4, and the additives used basically have no effect on the SiO2 removal rate. However, as the transistor density of integrated circuits gradually increases and the technology nodes continue to progress, STI CMP requires minimizing serious trench oxide loss and dishing defects caused by too fast a SiO2 removal rate. Therefore, a suitable SiO2 removal rate under high removal rate selectivity ratio conditions is an urgent problem to be solved. Summary of the Invention

[0004] In view of the problems existing in the prior art, in the research on the removal rate selectivity ratio of STI CMP, such as serious trench oxide loss and dishing defects caused by too fast a SiO2 removal rate by additives, the present invention provides a preparation method for a cerium oxide polishing liquid. The product obtained by the preparation method of the cerium oxide polishing liquid of the present invention has one or more of the following advantages: controlling and adjusting the removal rate of the polishing liquid, reducing trench oxide loss; slowing down the SiO2 removal rate; being able to reduce the dishing amount in the trench part of the 100μm / 100μm area; or, increasing the removal selectivity ratio of the polishing liquid for the silicon oxide film RR / silicon nitride film RR.

[0005] The present invention solves the above technical problems through the following technical solutions.

[0006] The present invention provides a cerium oxide polishing liquid, which comprises components with the following mass fractions: 0.1%-10% cerium oxide abrasive particles, 0.1-5% polishing inhibitor, 0.01-5% dispersant, 0.01-2% pH regulator, 50-500 ppm anionic surfactant, and water; the polishing inhibitor is polymethacrylic acid (PMAA); the sum of the mass fractions of each component is 100%, and the mass fraction is the mass percentage of the mass of each component in the total mass of each component.

[0007] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the polymethacrylic acid has a weight average molecular weight of 2000-20000.

[0008] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the cerium oxide abrasive particles are spherical or nearly spherical.

[0009] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the average particle size of the cerium oxide abrasive particles is 50-300 nanometers, preferably 80-180 nanometers, for example, preferably 150 nanometers.

[0010] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the content of the cerium oxide abrasive particles is 4-6%, preferably 5%.

[0011] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the content of the polishing inhibitor is 1%-3%, preferably 1%, 1.5%, 2% or 3%.

[0012] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the dispersant is a common dispersant in the art, preferably one or more of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine or histidine, more preferably glycine or alanine.

[0013] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the content of the dispersant is 0.5%-2%, preferably 0.8%.

[0014] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the pH regulator is an inorganic base or an organic base.

[0015] Among them, the inorganic base is preferably ammonia water. The organic base is preferably a quaternary amine base, more preferably choline.

[0016] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the content of the pH regulator is 0.3%-1%, preferably 0.5% or 0.6%.

[0017] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the anionic surfactant is a carboxylate or a sulfonate.

[0018] Among them, the carboxylates are preferably carboxylates or carboxylic acid esters and salts, more preferably fatty alcohol polyether-n carboxylate salts.

[0019] The sulfonates in the cerium oxide polishing liquid are preferably one or more of alkyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates or sulfosuccinate esters, more preferably sodium dodecyl benzene sulfonate.

[0020] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the content of the anionic surfactant is 100 ppm - 200 ppm, preferably 150 ppm.

[0021] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the water is one or more of deionized water, distilled water and ultrapure water, such as deionized water.

[0022] In a certain embodiment of the present invention, the cerium oxide polishing liquid comprises the following components by mass fraction: 4-6% cerium oxide abrasive particles, 1.5-3% polymethacrylic acid, 0.7-0.9% glycine, 0.5-0.6% pH regulator, 140-160 ppm sodium dodecyl benzene sulfonate, and water;

[0023] The dispersant is glycine and / or alanine; the pH value of the cerium oxide polishing liquid is 6; the pH regulator is ammonia water and / or choline.

[0024] In certain preferred embodiments of the present invention, the cerium oxide polishing liquid comprises the following components:

[0025] (1) 5% cerium oxide abrasive particles, 1% polishing inhibitor, 0.8% dispersant, 0.5% pH regulator, 150 ppm anionic surfactant, and the balance water;

[0026] (2) 5% cerium oxide abrasive particles, 1.5% polishing inhibitor, 0.8% dispersant, 0.5% pH regulator, 150 ppm anionic surfactant, and the balance water;

[0027] (3) 5% cerium oxide abrasive particles, 2% polishing inhibitor, 0.8% dispersant, 0.6% pH regulator, 150 ppm anionic surfactant, and the balance water;

[0028] (4) 5% cerium oxide abrasive particles, 3% polishing inhibitor, 0.8% dispersant, 0.6% pH regulator, 150 ppm anionic surfactant, and the balance water;

[0029] In (1)-(4) thereof, the cerium oxide abrasive particles, the polishing inhibitor, the dispersant, the pH regulator, the anionic surfactant, and the water are all as described above; the pH of the cerium oxide polishing liquid is 6.

[0030] In one embodiment of the present invention, the cerium oxide polishing liquid is composed of the following components by mass fraction: 1%-7% cerium oxide abrasive particles, 0.5-3% polishing inhibitor, 0.05-1% dispersant, 0.05-2% pH regulator, 100-200 ppm anionic surfactant, and the balance water.

[0031] In certain preferred embodiments of the present invention, the cerium oxide polishing liquid is composed of the following components:

[0032] (1) 5% cerium oxide abrasive particles, 1% polymethacrylic acid, 0.8% glycine, 0.5% ammonia water, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0033] (2) 5% cerium oxide abrasive particles, 1.5% polymethacrylic acid, 0.8% glycine, 0.5% ammonia water, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0034] (3) 5% cerium oxide abrasive particles, 2% polymethacrylic acid, 0.8% glycine, 0.6% ammonia water, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0035] (4) 5% cerium oxide abrasive particles, 3% polymethacrylic acid, 0.8% glycine, 0.6% ammonia water, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0036] (5) 5% cerium oxide abrasive particles, 1% polymethacrylic acid, 0.8% alanine, 0.5% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0037] (6) 5% cerium oxide abrasive particles, 1.5% polymethacrylic acid, 0.8% alanine, 0.5% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0038] (7) 5% cerium oxide abrasive particles, 2% polymethacrylic acid, 0.8% alanine, 0.6% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0039] (8) 5% cerium oxide abrasive particles, 3% polymethacrylic acid, 0.8% alanine, 0.6% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0040] The mass fraction mentioned refers to the percentage of the mass of each component in the total mass of all components; the particle size of the cerium oxide abrasive particles in the cerium oxide polishing liquid is 150 nanometers; the pH of the cerium oxide polishing liquid is 6.

[0041] The present invention also provides a preparation method of the above-mentioned cerium oxide polishing liquid, which includes the following steps: Mix the components in the cerium oxide polishing liquid to obtain the cerium oxide polishing liquid.

[0042] In a certain embodiment of the present invention, the temperature of the mixing is 20 - 35 °C, for example, 25 °C.

[0043] In a certain embodiment of the present invention, the mixing time is 0.5 - 2 h; preferably 1 h.

[0044] In a certain embodiment of the present invention, the pH of the cerium oxide polishing liquid is 4 - 7, preferably 6.

[0045] In a certain embodiment of the present invention, the polishing selectivity ratio of the cerium oxide polishing liquid for the silicon oxide film / silicon nitride film is 25 - 35, preferably 28 - 32; for example, 28.5, 29.7, 31.2, 31.6, 29.3, 30.9, 30.4, 31.5.

[0046] The present invention also provides an application of the above-mentioned cerium oxide polishing liquid in the chemical mechanical polishing process (CMP) in integrated circuit manufacturing.

[0047] Among them, the integrated circuit manufacturing plays an isolation role in high-density transistors through the shallow trench structure; the surface of the integrated circuit manufacturing contains silicon materials, such as SiO2 or SiN;

[0048] Among them, the slurry flow rate of the chemical mechanical polishing process can be the slurry flow rate used in the art, for example, 50 ml / min - 500 ml / min, preferably 200 ml / min; the time of the chemical mechanical polishing process can be 10 s - 5 min (for example, 60 s).

[0049] On the basis of not violating the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0050] The reagents and raw materials used in the present invention are all commercially available. Among them, the spherical cerium oxide abrasive particles with a particle size of 150 nm are purchased from Leshan Dongcheng New Materials Co., Ltd.; polymethacrylic acid is purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0051] The positive and progressive effects of the present invention are as follows: The polishing liquid prepared by the preparation method of the present invention has at least one or more of the following advantages: It can control and adjust the removal rate of the polishing liquid, reduce the loss of trench oxides; slow down the removal rate of SiO2, and can reduce the dishing amount of the trench part in the 100 μm / 100 μm area relative to the silicon nitride film, and can selectively remove the silicon oxide film, having good application prospects. Specific Embodiments

[0052] I. Preparation of Preparation Examples 1-8 and Preparation Comparative Examples 1-4

[0053] Preparation of the Polishing Liquid

[0054] Raw materials: Spherical cerium oxide abrasive particles with a particle size of 150 nm, polishing inhibitor, dispersant, pH regulator, anionic surfactant, and water.

[0055] At 25 °C, water, spherical cerium oxide abrasive particles with a particle size of 150 nm, polishing inhibitor, dispersant, and anionic surfactant are sequentially added to a container and mixed, and then the pH value is adjusted with a pH regulator, and then mechanically stirred for 1 hour until evenly mixed to obtain a cerium oxide polishing liquid.

[0056] Table 1 Types of Components of the Polishing Agent

[0057] Example Abrasive particles Polishing inhibitor Dispersant pH regulator Anionic surfactant Water Example 1 Cerium oxide Polymethacrylic acid Glycine Ammonia water Sodium dodecylbenzenesulfonate Deionized water Example 2 Cerium oxide Polymethacrylic acid Glycine Ammonia water Sodium dodecylbenzenesulfonate Deionized water Example 3 Cerium oxide Polymethacrylic acid Glycine Ammonia water Sodium dodecylbenzenesulfonate Deionized water Example 4 Cerium oxide Polymethacrylic acid Glycine Ammonia water Sodium dodecylbenzenesulfonate Deionized water Example 5 Cerium oxide Polymethacrylic acid Alanine Choline Sodium dodecylbenzenesulfonate Deionized water Example 6 Cerium oxide Polymethacrylic acid Alanine Choline Sodium dodecylbenzenesulfonate Deionized water Example 7 Cerium oxide Polymethacrylic acid Alanine Choline Sodium dodecylbenzenesulfonate Deionized water Example 8 Cerium oxide Polymethacrylic acid Alanine Choline Sodium dodecylbenzenesulfonate Deionized water Comparative example 1 Cerium oxide Polymethacrylic acid Glycine Choline Sodium dodecylbenzenesulfonate Deionized water Comparative example 2 Cerium oxide Polymethacrylic acid Alanine Ammonia water Sodium dodecylbenzenesulfonate Deionized water Comparative example 3 Cerium oxide - Glycine Choline Sodium dodecylbenzenesulfonate Deionized water Comparative example 4 Cerium oxide - Alanine Ammonia water Sodium dodecylbenzenesulfonate Deionized water

[0058] Table 2 Mass Percentages of Components of the Polishing Agent

[0059]

[0060]

[0061] The "balance" in the table means, in each embodiment, 100% minus the mass percentage of other components.

[0062] II. Polishing Effect Experiment

[0063] The polishing conditions are as follows

[0064] 1. Polishing device: AP-300 (CTS)

[0065] 2. Pad: Dow Chemical IC1010

[0066] 3. Polishing time: 60 s

[0067] 4. Polishing temperature: room temperature, 25 °C

[0068] 5. Platen speed: 110 rpm

[0069] 6. Spindle speed: 108 rpm

[0070] 7. Wafer pressure: 3.5 psi

[0071] 8. Slurry flow rate: 200 ml / min

[0072] 9. Wafers: PE-TEOS (thickness 6KA); silicon nitride wafer (thickness 6KA); patterned wafer (15KA) Surface roughness Ra (nm): Surface roughness.

[0073] Polishing rate (RR) of silicon oxide film: Measured by Filmetrics F54 film thickness measuring instrument

[0074] Polishing rate of silicon nitride film: Measured by Filmetrics F54 film thickness measuring instrument

[0075] Selectivity: RR of silicon oxide film / RR of silicon nitride film

[0076] Dishing amount of the trench part in the 100μm / 100μm area: Measured using a stylus profilometer (manufactured by P16KLA-tencor)

[0077] Before each polishing, the polishing pad is dressed with a diamond dresser for 5 minutes to minimize the polishing error caused by the previous polishing as much as possible. The polished wafers are rinsed with deionized water and dried with high-purity N2.

[0078] The polishing effects of Examples 1-8 and Comparative Examples 1-4 were tested, and the results are shown in Table 3 below.

[0079] Table 3 Polishing effect of polishing agent

[0080]

[0081] It can be seen from the examples that polymethacrylic acid can inhibit the activity of Ce in cerium oxide particles, has a certain inhibitory effect on the etching rates of silicon oxide and silicon nitride, is easy to control and adjust the removal rate of the polishing liquid, and improves the selectivity. 3+ and improve the selectivity.

[0082] In the comparative example, when the addition amount of the inhibitor is too high, such as higher than 5%, the polishing rate of the silicon oxide film will be significantly reduced, affecting the production efficiency; if the inhibitor is not added, the etching rates of both silicon oxide and silicon nitride are relatively fast, and the selectivity is about 12 at this time, resulting in an excessive removal amount of silicon nitride after polishing is completed.

Claims

1. A cerium oxide polishing liquid, characterized in that, It contains components with the following mass fractions: 0.1%-10% cerium oxide abrasive particles, 0.1-5% polishing inhibitor, 0.01-5% dispersant, 0.01-2% pH regulator, 50-500 ppm anionic surfactant, and water; The polishing inhibitor is polymethacrylic acid; the sum of the mass fractions of each component is 100%, and the mass fraction is the mass percentage of the mass of each component in the total mass of each component.

2. The cerium oxide polishing liquid according to claim 1, wherein In the cerium oxide polishing liquid, the polymethacrylic acid has a weight-average molecular weight of 2000-20000; And / or, in the cerium oxide polishing liquid, the cerium oxide abrasive particles are spherical or nearly spherical; And / or, in the cerium oxide polishing liquid, the average particle size of the cerium oxide abrasive particles is 50-300 nanometers; And / or, in the cerium oxide polishing liquid, the dispersant is one or more of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, or histidine; And / or, in the cerium oxide polishing liquid, the pH regulator is an inorganic base or an organic base; And / or, in the cerium oxide polishing liquid, the anionic surfactant is a carboxylate or a sulfonate; And / or, in the cerium oxide polishing liquid, the water is one or more of deionized water, distilled water, and ultrapure water.

3. The cerium oxide polishing liquid according to claim 2, wherein In the cerium oxide polishing liquid, the average particle size of the cerium oxide abrasive particles is 80-180 nanometers; And / or, in the cerium oxide polishing liquid, the dispersant is glycine or alanine; And / or, in the cerium oxide polishing liquid, the inorganic base is ammonia water; And / or, in the cerium oxide polishing liquid, the organic base is a quaternary amine base; And / or, in the cerium oxide polishing liquid, the carboxylates are carboxylates or carboxylate esters and salts; And / or, in the cerium oxide polishing liquid, the sulfonates are one or more of alkyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, or succinate ester sulfonates; And / or, in the cerium oxide polishing liquid, the water is deionized water.

4. The cerium oxide polishing liquid according to claim 3, characterized in that, In the cerium oxide polishing liquid, the average particle size of the cerium oxide abrasive particles in the cerium oxide polishing liquid is 150 nanometers; And / or, in the cerium oxide polishing liquid, the organic base is choline; And / or, in the cerium oxide polishing liquid, the carboxylates are fatty alcohol polyether-n carboxylate salts; And / or, in the cerium oxide polishing liquid, the sulfonates are sodium dodecylbenzenesulfonate.

5. The cerium oxide polishing liquid according to claim 1, wherein In the cerium oxide polishing liquid, the content of the cerium oxide abrasive particles is 4-6%; And / or, in the cerium oxide polishing liquid, the content of the polishing inhibitor is 1%-3%; And / or, in the cerium oxide polishing liquid, the content of the dispersant is 0.5%-2%; And / or, in the cerium oxide polishing liquid, the content of the pH regulator is 0.3%-1%; And / or, in the cerium oxide polishing liquid, the content of the anionic surfactant is 100 ppm - 200 ppm.

6. The cerium oxide polishing liquid according to claim 5, wherein, In the cerium oxide polishing liquid, the content of the cerium oxide grinding particles in the cerium oxide polishing liquid is 5%; And / or, in the cerium oxide polishing liquid, the content of the polishing inhibitor is 1%, 1.5%, 2% or 3%; And / or, in the cerium oxide polishing liquid, the content of the dispersant is 0.8%; And / or, in the cerium oxide polishing liquid, the content of the pH regulator is 0.5% - 0.6%; And / or, in the cerium oxide polishing liquid, the content of the anionic surfactant is 150 ppm.

7. The cerium oxide polishing liquid according to claim 1, wherein The cerium oxide polishing liquid comprises the following components by mass fraction: 4 - 6% cerium oxide grinding particles, 1.5 - 3% polymethacrylic acid, 0.7 - 0.9% glycine, 0.5 - 0.6% pH regulator, 140 - 160 ppm sodium dodecylbenzenesulfonate, and water; The dispersant is glycine and / or alanine; the pH value of the cerium oxide polishing liquid is 6; the pH regulator is ammonia water and / or choline.

8. The cerium oxide polishing liquid according to any one of claims 1-4, characterized in that, The cerium oxide polishing liquid comprises any one of the following components: (1) 5% cerium oxide grinding particles, 1% polishing inhibitor, 0.8% dispersant, 0.5% pH regulator, 150 ppm anionic surfactant, and the balance water; (2) 5% cerium oxide grinding particles, 1.5% polishing inhibitor, 0.8% dispersant, 0.5% pH regulator, 150 ppm anionic surfactant, and the balance water; (3) 5% cerium oxide grinding particles, 2% polishing inhibitor, 0.8% dispersant, 0.6% pH regulator, 150 ppm anionic surfactant, and the balance water; (4) 5% cerium oxide grinding particles, 3% polishing inhibitor, 0.8% dispersant, 0.6% pH regulator, 150 ppm anionic surfactant, and the balance water; In (1) - (4) thereof, the cerium oxide grinding particles, the polishing inhibitor, the dispersant, the pH regulator, the anionic surfactant, and the water are all as described in any one of claims 1 - 4; the pH of the cerium oxide polishing liquid is 6.

9. The cerium oxide polishing liquid according to any one of claims 1-4, characterized in that, The cerium oxide polishing liquid is composed of the following components by mass fraction: 1% - 7% cerium oxide grinding particles as described in any one of claims 1 - 4, 0.5 - 3% polishing inhibitor as described in any one of claims 1 - 4, 0.05 - 1% dispersant as described in any one of claims 1 - 4, 0.05 - 2% pH regulator as described in any one of claims 1 - 4, 100 - 200 ppm anionic surfactant as described in any one of claims 1 - 4, and the balance water.

10. The cerium oxide polishing liquid according to claim 1, wherein, The cerium oxide polishing liquid is composed of any one of the following components: (1) 5% cerium oxide grinding particles, 1% polymethacrylic acid, 0.8% glycine, 0.5% ammonia water, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water; (2) 5% cerium oxide abrasive particles, 1.5% polymethacrylic acid, 0.8% glycine, 0.5% ammonia water, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water; (3) 5% cerium oxide abrasive particles, 2% polymethacrylic acid, 0.8% glycine, 0.6% ammonia water, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water; (4) 5% cerium oxide abrasive particles, 3% polymethacrylic acid, 0.8% glycine, 0.6% ammonia water, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water; (5) 5% cerium oxide abrasive particles, 1% polymethacrylic acid, 0.8% alanine, 0.5% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water; (6) 5% cerium oxide abrasive particles, 1.5% polymethacrylic acid, 0.8% alanine, 0.5% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water; (7) 5% cerium oxide abrasive particles, 2% polymethacrylic acid, 0.8% alanine, 0.6% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water; (8) 5% cerium oxide abrasive particles, 3% polymethacrylic acid, 0.8% alanine, 0.6% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water; Among them, the particle size of the cerium oxide abrasive particles in the cerium oxide polishing liquid is 150 nanometers; the pH of the cerium oxide polishing liquid is 6.

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