Application of cerium oxide polishing solution

Abstract

The invention discloses application of a cerium oxide polishing solution. The cerium oxide polishing solution is applied to a chemical mechanical polishing process in integrated circuit manufacturing and comprises the following components in percentage by mass: 0.1%-10% of cerium oxide grinding particles, 0.1%-5% of a light 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 an application of 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 on the premise of a relatively high SiO2 removal rate. The removal of SiO2 dielectric by SiO2 sol polishing relies only on mechanical action, resulting in a relatively low removal rate of SiO2 dielectric, and thus the selectivity ratio of the removal rates of SiO2 and Si3N4 is too low.

[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 selected 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 problems such as severe 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 severe trench oxide loss and dishing defects caused by too fast a SiO2 removal rate, the present invention provides a cerium oxide polishing liquid composition, its preparation method, and applications. The positive and progressive effects of the present invention meet one or more of the following: controlling and adjusting the removal rate of the polishing liquid, reducing trench oxide loss; slowing down the SiO2 removal rate, capable of reducing the dishing amount in the trench part of the 100μm / 100μm area; 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, and more preferably glycine or alanine.

[0013] 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%.

[0014] 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%.

[0015] 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.

[0016] Among them, the inorganic base is preferably ammonia water. The organic base is preferably a quaternary amine base, more preferably choline.

[0017] 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%.

[0018] In a certain embodiment of the present invention, in the cerium oxide polishing liquid, the anionic surfactant is a carboxylate or a sulfonate.

[0019] Among them, the carboxylates are preferably carboxylates or carboxylic esters and their salts, more preferably fatty alcohol polyether-n carboxylate salts.

[0020] In the cerium oxide polishing liquid, the sulfonates are preferably one or more of alkyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates or sulfosuccinates, more preferably sodium dodecyl benzene sulfonate.

[0021] 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.

[0022] 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.

[0023] 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;

[0024] 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.

[0025] In a certain 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.

[0026] In some preferred embodiments of the present invention, the cerium oxide polishing liquid comprises the following components:

[0027] (1) 5% cerium oxide abrasive particles, 1% polishing inhibitor, 0.8% dispersant, 0.5% pH regulator, 150 ppm anionic surfactant, and the balance water;

[0028] (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;

[0029] (3) 5% cerium oxide abrasive particles, 2% polishing inhibitor, 0.8% dispersant, 0.6% pH regulator, 150 ppm anionic surfactant, and the balance water;

[0030] (4) % cerium oxide abrasive particles, 3% polishing inhibitor, 0.8% dispersant, 0.6% pH regulator, 150 ppm anionic surfactant, and the balance water;

[0031] 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.

[0032] In certain preferred embodiments of the present invention, the cerium oxide polishing liquid comprises the following components:

[0033] (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;

[0034] (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;

[0035] (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;

[0036] (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;

[0037] (5) 5% cerium oxide abrasive particles, 1% polymethacrylic acid, 0.8% alanine, 0.5% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0038] (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;

[0039] (7) 5% cerium oxide abrasive particles, 2% polymethacrylic acid, 0.8% alanine, 0.6% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0040] (8) 5% cerium oxide abrasive particles, 3% polymethacrylic acid, 0.8% alanine, 0.6% choline, 150 ppm sodium dodecylbenzenesulfonate, and the balance deionized water;

[0041] 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.

[0042] The present invention also provides a preparation method of the above-mentioned cerium oxide polishing liquid, which includes the following steps: mixing each component in the cerium oxide polishing liquid to obtain the cerium oxide polishing liquid.

[0043] In a certain embodiment of the present invention, the temperature of the mixing is 20 - 35 °C, such as 25 °C.

[0044] In a certain embodiment of the present invention, the time of the mixing is 0.5 - 2 h; preferably 1 h.

[0045] In a certain embodiment of the present invention, the pH of the cerium oxide polishing liquid is 4 - 7, preferably 6.

[0046] 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; such as 28.5, 29.7, 31.2, 31.6, 29.3, 30.9, 30.4, 31.5.

[0047] 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.

[0048] Among them, the integrated circuit manufacturing plays an isolation role in high-density transistors through a shallow trench structure; the surface of the integrated circuit manufacturing contains silicon materials, such as SiO2 or SiN.

[0049] Among them, the slurry flow rate of the chemical mechanical polishing process can be the slurry flow rate used in the art, such as 50 ml / min - 500 ml / min, preferably 200 ml / min. The time of the chemical mechanical polishing process can be 10 s - 5 min (such as 60 s).

[0050] 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.

[0051] All the reagents and raw materials used in the present invention are commercially available. Among them, the spherical cerium oxide grinding 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.

[0052] The positive and progressive effects of the present invention are as follows: The polishing liquid of the present invention has at least one or more of the following advantages: controlling and adjusting the removal rate of the polishing liquid, reducing the loss of trench oxides; slowing down the removal rate of SiO2, and being able to reduce the dishing amount of the trench part in the 100 μm / 100 μm area; improving the removal selectivity ratio of the polishing liquid for the silicon oxide film / silicon nitride film. Specific Embodiments

[0053] I. Preparation of Preparation Examples 1-8 and Preparation Comparative Examples 1-4

[0054] Preparation of the Polishing Liquid

[0055] Raw materials: spherical cerium oxide grinding particles with a particle size of 150 nm, polishing inhibitor, dispersant, pH regulator, anionic surfactant, and water.

[0056] At 25°C, water, spherical cerium oxide grinding particles with a particle size of 150 nm, polishing inhibitor, dispersant, and anionic surfactant are sequentially added to a container and mixed. Subsequently, 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.

[0057] Table 1 Types of Components of the Polishing Agent

[0058] 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

[0059] Table 2 Mass Percentages of Components of the Polishing Agent

[0060]

[0061] The "balance" in the table is, in each example, 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: 110rpm

[0069] 6. Spindle speed: 108rpm

[0070] 7. Wafer pressure: 3.5psi

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

[0072] 9. Wafer: PE-TEOS (thickness 6KA); silicon nitride wafer (thickness 6KA); patterned wafer (15KA)

[0073] Surface roughness Ra (nm): surface roughness.

[0074] Silicon oxide film polishing rate (RR): measured using Filmetrics F54 film thickness meter

[0075] Silicon nitride film polishing rate: measured using Filmetrics F54 film thickness meter

[0076] Selectivity ratio: Silicon oxide film RR / Silicon nitride film RR

[0077] The dishing amount of the groove portion in the 100 μm / 100 μm region was measured using a stylus step profiler (model P16 manufactured by KLA-tencor).

[0078] Before each polishing, the polishing pad was trimmed for 5 minutes using a diamond dresser to minimize the polishing error caused by the previous polishing. The polished wafer was rinsed with deionized water and dried with high-purity N2.

[0079] The polishing effect of Examples 1-8 and Comparative Examples 1-4 was tested, and the results are shown in Table 3 below.

[0080] Table 3 Polishing effect of polishing agent

[0081]

[0082] It can be seen from the examples that polymethacrylic acid can inhibit the Ce in cerium oxide particles. 3+ The activity of the polishing liquid can inhibit the etching speed of silicon oxide and silicon nitride to a certain extent, making it easy to control and adjust the removal rate of the polishing liquid and improve the selectivity.

[0083] In the comparative example, if the amount of inhibitor added is too high, such as higher than 5%, the polishing rate of the silicon oxide film will be greatly reduced, affecting the production efficiency; if no inhibitor is added, the etching rates of silicon oxide and silicon nitride are both fast, and the selectivity is about 12 at this time, and the amount of silicon nitride removed after polishing is too large.

Claims

1. Application of a cerium oxide polishing liquid, characterized in that, The application described is for use in the chemical mechanical polishing process in integrated circuit manufacturing; the cerium oxide polishing liquid comprises the following components by mass fraction: 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, and the sum of the mass fractions of each component is 100%; Wherein the polishing inhibitor is polymethacrylic acid.

2. The application according to claim 1, wherein The surface of the integrated circuit manufacturing contains silicon materials, such as SiO2 or SiN; And / or, the flow rate of the cerium oxide polishing liquid in the chemical mechanical polishing process is 50 ml / min - 500 ml / min, preferably 200 ml / min; And / or, the time of the chemical mechanical polishing process can be 10 s - 5 min, preferably 60 s; And / or, the temperature of the chemical mechanical polishing process is 25 °C.

3. The application according to claim 1, characterized in that In the application described, the weight average molecular weight of the polymethacrylic acid is 2000 - 20000; And / or, in the application described, the cerium oxide abrasive particles are spherical or nearly spherical; And / or, in the application described, the average particle size of the cerium oxide abrasive particles is 50 - 300 nanometers; And / or, in the application described, 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 application described, the pH regulator is an inorganic base or an organic base; And / or, in the application described, the anionic surfactant is a carboxylate salt or a sulfonate salt; And / or, in the application described, the water is one or more of deionized water, distilled water, and ultrapure water.

4. The application according to claim 3, 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 quaternary amine base; And / or, in the cerium oxide polishing liquid, the carboxylate salts are carboxylates or carboxylate esters and their salts; And / or, in the cerium oxide polishing liquid, the sulfonate salts are one or more of alkyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, or sulfosuccinate esters; And / or, in the cerium oxide polishing liquid, the water is deionized water.

5. The application according to claim 4, 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 carboxylate salts are fatty alcohol polyether-n carboxylate salts; And / or, in the cerium oxide polishing liquid, the sulfonate salts are sodium dodecylbenzenesulfonate.

6. The application according to claim 1, characterized in that In the cerium oxide polishing liquid described above, the content of the cerium oxide abrasive particles is 4-6%, preferably 5%; And / or, in the cerium oxide polishing liquid described above, the content of the polishing inhibitor is 1%-3%, preferably 1%, 1.5%, 2% or 3%; And / or, in the cerium oxide polishing liquid described above, the content of the dispersant is 0.5%-2%, preferably 0.8%; And / or, in the cerium oxide polishing liquid described above, the content of the pH regulator is 0.3%-1%, preferably 0.5%-0.6%; And / or, in the cerium oxide polishing liquid described above, the content of the anionic surfactant is 100 ppm-200 ppm, preferably 150 ppm.

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

9. The application according to any one of claims 1-5, characterized in that The cerium oxide polishing liquid is composed of the following components by mass fraction: 1% -7% cerium oxide abrasive particles as described in any one of claims 1-5, 0.5-3% polishing inhibitor as described in any one of claims 1-5, 0.05-1% dispersant as described in any one of claims 1-5, 0.05-2% pH regulator as described in any one of claims 1-5, 100-200 ppm anionic surfactant as described in any one of claims 1-5, and the balance water.

10. The application according to claim 1, wherein The cerium oxide polishing liquid is composed of any one of the following components: (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; (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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