A wafer polishing slurry, its preparation method and application

Abstract

This invention belongs to the field of material surface treatment technology, specifically relating to a wafer polishing slurry, its preparation method, and its application. The wafer polishing slurry comprises abrasives, oxidants, dispersants, surfactants, pH adjusters, and water. The components of the wafer polishing slurry work synergistically, shortening polishing time and improving polishing efficiency when applied to wafer polishing. Furthermore, it significantly improves the surface quality of the polished wafer, markedly reducing scratches and defects, and lowering surface roughness to below 0.15 nm, thus meeting the surface quality requirements of fields such as power electronics and radio frequency devices.

Description

Technical Field

[0001] This invention belongs to the field of material surface treatment technology, specifically relating to a wafer polishing fluid, its preparation method, and its application. Background Technology

[0002] Polishing is a crucial step in the field of material surface treatment technology. Silicon carbide (SiC) wafers are a key material in semiconductor manufacturing. Polishing wafers is generally used to improve wafer surface flatness, reduce wafer surface roughness, and remove damaged layers on the wafer surface. Polishing is essential for the quality of wafer materials and directly affects the performance and yield of subsequent device manufacturing.

[0003] Currently, there are various types of polishing slurries commonly used. Among them, alumina polishing slurries are widely used due to the high hardness and good chemical stability of alumina. Meanwhile, potassium permanganate, as a strong oxidizing agent, can also play a role in assisting oxidation and improving polishing results in certain polishing processes. However, existing polishing technologies have the following drawbacks: 1. Poor surface quality: The surface of materials polished by existing polishing slurries may have defects such as scratches and uneven TTV (total thickness deviation), which cannot meet the application scenarios with extremely high surface quality requirements in fields such as power electronics and radio frequency devices; 2. Low polishing efficiency: When polishing wafers, traditional alumina polishing slurries rely solely on the mechanical grinding action of alumina particles, which often requires a long polishing time to achieve the required surface roughness, resulting in low production efficiency. Summary of the Invention

[0004] Therefore, one of the technical problems to be solved by the present invention is to overcome the defect of poor surface quality of wafers after polishing with existing polishing solutions, thereby providing a wafer polishing solution and its preparation method and application.

[0005] The second technical problem to be solved by the present invention is to overcome the defect of low polishing efficiency of existing polishing slurries, thereby providing a wafer polishing slurry, its preparation method and application.

[0006] Therefore, the present invention provides the following technical solution: The first aspect of this invention protects a wafer polishing slurry, wherein the wafer polishing slurry comprises abrasive, oxidant, dispersant, surfactant, pH adjuster and water.

[0007] In this invention, the water is conventional laboratory water, and typically, without limitation, the water is deionized water.

[0008] In this invention, an a-AB33 pH meter is used. The number of measurements is determined based on the actual reaction conditions, typically and non-limitingly every 30 minutes, to monitor the pH value of the system. After preparation, various indicators of the product are measured to ensure the system remains constant. The pH adjuster includes at least one of sulfuric acid, formic acid, phosphoric acid, citric acid, hydrochloric acid, oxalic acid, and boric acid; the specific concentration is determined based on actual conditions, ensuring the system pH meets the requirements, without excessive limitations.

[0009] In this invention, the wafer polishing slurry should be properly stored in a cool, dry and well-ventilated environment, avoiding direct sunlight and high temperatures, to prevent environmental factors from causing changes in the performance of the wafer polishing slurry and thus affecting its performance.

[0010] In one alternative implementation, the wafer polishing slurry comprises, by weight: 5-15 parts by weight of abrasive; 2 to 8 parts by weight of oxidant; 2-6 parts by weight of dispersant; 2 to 5 parts by weight of surfactant; The remaining part is water; The pH of the wafer polishing solution is 1.5-3.5.

[0011] In one alternative implementation, the wafer polishing slurry comprises, by weight: 5-10 parts by weight of abrasive; 4-6 parts by weight of oxidant; 3-5 parts by weight of dispersant; 2 to 4 parts by weight of surfactant; The pH of the wafer polishing solution is 1.7-2.5; The remaining part is water.

[0012] In one optional embodiment, the average particle size of the abrasive is 30 nm-1 μm, optionally 40-200 nm.

[0013] In one optional embodiment, the abrasive includes at least one of alumina, zirconium oxide, silicon carbide, silicon oxide, and manganese oxide. Optionally, the abrasive is alumina and silicon oxide, and may be alumina and silicon oxide in a mass ratio of 7:3.

[0014] In this invention, the oxidant includes at least one of potassium permanganate, nitric acid, and hydrogen peroxide.

[0015] In this invention, the dispersant includes at least one of polyphosphate compounds, polyacrylamide polymers, and fatty alcohol (ether) phosphate compounds. Optionally, the dispersant includes at least one of sodium tripolyphosphate, sodium hexametaphosphate, sodium pyrophosphate, polyacrylamide, fatty alcohol ether phosphate, potassium salt of fatty alcohol ether phosphate, and isothietol phosphate.

[0016] In one optional embodiment, the surfactant includes at least one of cationic surfactants, anionic surfactants, amphoteric surfactants, and nonionic surfactants.

[0017] In one alternative embodiment, the cationic surfactant includes at least one of dodecyltrimethylammonium chloride and hexadecyltrimethylammonium bromide.

[0018] In one optional embodiment, the anionic surfactant includes at least one of sodium alkylbenzene sulfonate and sodium alkyl sulfate, optionally including sodium dodecylbenzene sulfonate and / or sodium dodecyl sulfate.

[0019] In one alternative embodiment, the amphoteric surfactant includes at least one of imidazoline derivatives, amino acid types, and lecithin.

[0020] In one alternative embodiment, the nonionic surfactant includes at least one of glycerol fatty acid esters, sorbitol fatty acid esters, and fatty alcohol polyoxyethylene ethers.

[0021] A second aspect of this invention protects a method for preparing the aforementioned wafer polishing slurry, wherein the preparation method includes the following steps: mixing the components to obtain the wafer polishing slurry.

[0022] In one alternative implementation, the mixing is performed by stirring.

[0023] In this invention, the stirring is conventional stirring in the art, typically and non-limitingly, ultrasonic stirring is used.

[0024] In one optional embodiment, the stirring conditions include: a rotation speed of 100-300 r / min, a temperature of 20-30℃, and a time of 10-30 min.

[0025] Optionally, the stirring conditions include: a rotation speed of 250-280 r / min, a temperature of 20-25℃, and a time of 20-30 min.

[0026] In one optional embodiment, the preparation method includes the following steps: S1, mix the oxidant with water to obtain mixed solution A; S2, the abrasive is mixed with the mixed solution A to obtain mixed solution B; S3, mix the dispersant with the mixed solution B to obtain mixed solution C; S4, the surfactant is mixed with the mixed solution C to obtain mixed solution D; S5, mix the pH adjuster with the mixed solution D to obtain the wafer polishing solution.

[0027] In this invention, the mixing conditions in steps S1-S5 can be the same or different, and can be adjusted according to the actual situation.

[0028] The third aspect of this invention protects the application of the aforementioned wafer polishing slurry or the wafer polishing slurry prepared by the aforementioned preparation method in polishing wafers.

[0029] In this invention, the polished wafer can be applied to fields such as power electronics or radio frequency devices.

[0030] The technical solution of this invention has the following advantages: 1. This invention provides a wafer polishing slurry, wherein the wafer polishing slurry comprises abrasive, oxidant, dispersant, surfactant, pH adjuster, and water; the role of the oxidant in the wafer polishing slurry mainly involves promoting the chemical transformation of the material surface and regulating the reaction kinetics during the polishing process, thereby improving polishing efficiency and surface quality; the oxidant can preferentially react with atoms on the wafer surface to undergo oxidation reactions, transforming the difficult-to-process substrate into oxidation products with lower hardness and looser structure; while the abrasive removes the softened oxidation products and simultaneously removes the residual micro-damage layer on the wafer surface, thus avoiding scratches caused by the adhesion of oxidation products. This process reduces mechanical damage to the wafer surface caused by a single abrasive particle. Surfactants can adsorb onto the surface of abrasive particles, preventing particle agglomeration to some extent through electrostatic repulsion or steric hindrance. pH adjusters regulate the pH of the polishing slurry, ensuring sufficient activity of the abrasive and oxidant, resulting in a synergistic effect. When applied to polishing wafers, this shortens polishing time and improves polishing efficiency. Furthermore, it significantly improves the surface quality of the polished wafer, noticeably reducing scratches and other defects, and lowering surface roughness to below 0.15 nm, meeting the stringent surface quality requirements of fields such as power electronics and radio frequency devices.

[0031] 2. The amount of each component in the wafer polishing slurry of the present invention can further reduce the processing time of polishing wafers and result in smoother wafers and flatter surfaces.

[0032] 3. The specific types of surfactants in the wafer polishing slurry of this invention can further enhance the prevention of particle agglomeration through electrostatic repulsion or steric hindrance effects, thereby ensuring uniform suspension of the abrasive.

[0033] 4. The specific abrasive combination in the wafer polishing slurry of the present invention can further improve the control of surface quality, thereby removing scratches and oxide layers from the wafer surface and reducing its roughness.

[0034] 5. The specific pH conditions in the wafer polishing slurry of this invention can further enhance the sufficient activity of the abrasive and oxidant, thereby shortening the polishing time and improving the polishing efficiency when polishing wafers.

[0035] 6. This invention provides a method for preparing a wafer polishing slurry, comprising the following steps: S1, mixing an oxidant with water to obtain a mixed solution A; S2, mixing an abrasive with the mixed solution A to obtain a mixed solution B; S3, mixing a dispersant with the mixed solution B to obtain a mixed solution C; S4, mixing a surfactant with the mixed solution C to obtain a mixed solution D; S5, mixing a pH adjuster with the mixed solution D to obtain a wafer polishing slurry. The specific order of addition of each component in this invention ensures thorough mixing of all components, resulting in a wafer polishing slurry with good stability that remains stable for a long time, facilitating storage and transportation. When applied to wafer polishing, it shortens polishing time and improves polishing efficiency; it also significantly improves the surface quality of the polished wafer, with a marked reduction in scratches and other defects on the polished wafer surface. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 The image shows an AFM image of the silicon carbide surface after polishing with the wafer polishing slurry of Example 1. Figure 2 This is an AFM image of the silicon carbide surface after polishing with the wafer polishing slurry of Comparative Example 1. Detailed Implementation

[0038] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having” and any variations thereof in the text of this application are intended to cover non-exclusive inclusion.

[0040] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0041] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers from a to b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed herein, and "0-5" is merely a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥ 2, it is equivalent to disclosing that the parameter can be, for example, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0042] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0043] In the description of the embodiments of this application, the term "at least one" refers to one or more (including two).

[0044] The water used in the examples and comparative examples was deionized water; In the examples and comparative examples, 1 part by weight equals 1g.

[0045] Example 1 This embodiment provides a wafer polishing slurry, which, by weight, comprises: Eight parts by weight of abrasive, the abrasive being alumina and silicon oxide in a mass ratio of 7:3, wherein the average particle size of alumina is 200 nm and the average particle size of silicon oxide is 40 nm; 5 parts by weight of potassium permanganate; 3 parts by weight of sodium hexametaphosphate; 2 parts by weight of sodium dodecyl sulfate; The remaining part is water; The pH of the wafer polishing solution is 2.3; The wafer polishing slurry uses the dosage and type mentioned above, and its preparation method includes the following steps: S1. Potassium permanganate and water are mixed, and the stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution A; S2, Under stirring, the abrasive is added to the mixed solution A obtained in step S1. The stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution B. S3, Sodium hexametaphosphate is mixed with the mixed solution B obtained in step S2, the stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution C; S4, Sodium dodecyl sulfate is mixed with the mixed solution C obtained in step S3, the stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution D; S5, mix 8 mol / L nitric acid with the mixed solution D obtained in step S4, stir at 275 r / min, at 25℃ for 30 min to obtain wafer polishing solution.

[0046] Example 2 This embodiment provides a wafer polishing slurry, which, by weight, comprises: 8 parts by weight of alumina with an average particle size of 300 nm; 3 parts by weight of potassium permanganate; 2 parts by weight of polyacrylamide; 2 parts by weight of sodium dodecyl sulfate; The pH of the wafer polishing solution is 1.8; The remaining part is water; The wafer polishing slurry uses the dosage and type mentioned above, and its preparation method includes the following steps: S1. Potassium permanganate and water are mixed, and the stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution A; S2, Under stirring, alumina with an average particle size of 300 nm is added to the mixed solution A obtained in step S1. The stirring speed is 280 r / min, the temperature is 23℃, and the time is 20 min to obtain mixed solution B. S3, mix polyacrylamide with the mixed solution B obtained in step S2, stir at 260 r / min, at 30℃ for 22 min to obtain mixed solution C; S4, Sodium dodecyl sulfate is mixed with the mixed solution C obtained in step S3, the stirring speed is 220 r / min, the temperature is 30℃, and the time is 28 min to obtain mixed solution D; S5, mix 15 mol / L nitric acid with the mixed solution D obtained in step S4, stir at 290 r / min, at 25℃ for 27 min to obtain wafer polishing solution.

[0047] Example 3 This embodiment provides a wafer polishing slurry, which, by weight, comprises: 8 parts by weight of alumina with an average particle size of 200 nm; 3 parts by weight of potassium permanganate; 2 parts by weight of sodium hexametaphosphate; 2 parts by weight of sodium dodecyl sulfate; The pH of the wafer polishing solution is 1.8; The remaining part is water; The wafer polishing slurry used the amounts and types described above, and the preparation method followed the procedure in Example 1.

[0048] Example 4 This embodiment provides a wafer polishing fluid, which differs from Embodiment 1 in that "sodium dodecyl sulfate" is replaced with "sodium dodecylbenzene sulfonate"; The method for preparing wafer polishing slurry includes the following steps: The method is the same as in Example 1, except that in step S4, "sodium dodecyl sulfate" is replaced with "sodium dodecylbenzenesulfonate".

[0049] Example 5 This embodiment provides a wafer polishing slurry, which differs from Embodiment 1 in that "8 parts by weight of abrasive, the abrasive being alumina and silicon oxide in a mass ratio of 7:3, wherein the average particle size of alumina is 200nm and the average particle size of silicon oxide is 40nm" is changed to "8 parts by weight of alumina with an average particle size of 100nm". The method for preparing wafer polishing slurry includes the following steps: The method is the same as in Example 1, except that in step S2, "8 parts by weight of abrasive, the abrasive being alumina and silicon oxide in a mass ratio of 7:3, wherein the average particle size of alumina is 200 nm and the average particle size of silicon oxide is 40 nm" is changed to "8 parts by weight of alumina with an average particle size of 100 nm".

[0050] Example 6 This embodiment provides a wafer polishing solution, which differs from Embodiment 1 in that the pH of the wafer polishing solution is 3.0; The method for preparing wafer polishing slurry includes the following steps: The method is the same as in Example 1, except that in step S5, the amount of nitric acid is adjusted so that the pH of the resulting wafer polishing solution is 3.0.

[0051] Example 7 This embodiment provides a wafer polishing slurry, the preparation method of which includes the following steps: All components (abrasive, potassium permanganate, sodium hexametaphosphate, sodium dodecyl sulfate, pH adjuster and water) were mixed at the same amount as in Example 1, and the mixture was stirred at 275 r / min, at 25°C and for 150 min to obtain a wafer polishing solution.

[0052] Example 8 This embodiment provides a wafer polishing fluid, which is the same as that in Embodiment 1; The method for preparing wafer polishing slurry includes the following steps: S1. Potassium permanganate and deionized water are mixed, stirred at 100 r / min, at 30℃, for 10 min, to obtain mixed solution A; S2, Under stirring, the abrasive is added to the mixed solution A obtained in step S1. The stirring speed is 100 r / min, the temperature is 30℃, and the time is 10 min to obtain mixed solution B. S3, Sodium hexametaphosphate is mixed with the mixed solution B obtained in step S2, the stirring speed is 100 r / min, the temperature is 30℃, and the time is 10 min to obtain mixed solution C; S4, Sodium dodecyl sulfate is mixed with the mixed solution C obtained in step S3, the stirring speed is 100 r / min, the temperature is 30℃, and the time is 10 min to obtain mixed solution D; S5, mix 8 mol / L nitric acid with the mixed solution D obtained in step S4, stir at 100 r / min, at 30℃ for 10 min to obtain wafer polishing solution.

[0053] Comparative Example 1 This comparative example provides a polishing slurry that does not contain an oxidizing agent, i.e. 13 parts by weight of abrasive, the abrasive being alumina and silicon oxide in a mass ratio of 7:3, wherein the average particle size of alumina is 200 nm and the average particle size of silicon oxide is 40 nm; 3 parts by weight of sodium hexametaphosphate; 2 parts by weight of sodium dodecyl sulfate; The remaining part is water; The pH of the wafer polishing solution is 2.3; The wafer polishing slurry uses the dosage and type mentioned above, and its preparation method includes the following steps: S1, Under stirring, the abrasive and water are mixed at a speed of 275 r / min, a temperature of 25℃, and a time of 30 min to obtain mixed solution B; S2, Sodium hexametaphosphate is mixed with the mixed solution B obtained in step S1, the stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution C; S3, Sodium dodecyl sulfate is mixed with the mixed solution C obtained in step S2, the stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution D; S4. Mix 8 mol / L nitric acid with the mixed solution D obtained in step S3. Stir at 275 r / min, at 25℃, for 30 min to obtain the wafer polishing solution.

[0054] Comparative Example 2 This comparative example provides a polishing slurry that does not contain any surfactants, i.e. 10 parts by weight of abrasive, the abrasive being alumina and silicon oxide in a mass ratio of 7:3, wherein the average particle size of alumina is 200 nm and the average particle size of silicon oxide is 40 nm; 5 parts by weight of potassium permanganate; 3 parts by weight of sodium hexametaphosphate; The remaining part is water; The pH of the wafer polishing solution is 2.3; The wafer polishing slurry uses the dosage and type mentioned above, and its preparation method includes the following steps: S1. Potassium permanganate and water are mixed, and the stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution A; S2, Under stirring, the abrasive is added to the mixed solution A obtained in step S1. The stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution B. S3, Sodium hexametaphosphate is mixed with the mixed solution B obtained in step S2, the stirring speed is 275 r / min, the temperature is 25℃, and the time is 30 min to obtain mixed solution C; S4. Mix 8 mol / L nitric acid with the mixed solution C obtained in step S3. Stir at 275 r / min, at 25℃, for 30 min to obtain the wafer polishing solution.

[0055] Test case (1) Test method for the stability of polishing slurry: The wafer polishing slurries prepared in the examples and comparative examples were left to stand for 24 hours and the state of the wafer polishing slurries was observed. Test method for polishing slurry lifespan: Using the wafer polishing slurries from the examples and comparative examples, polish wafers in the same equipment with the same parameters for 2 hours each time. Without changing the polishing slurry, record the moment when the wafer removal rate after polishing for a given time period deviates from the previous time period. The time from the start of the test to the moment when the deviation occurs is defined as the polishing slurry lifespan. For example, if the wafer removal rate after polishing for the third time period deviates from the previous time period, the lifespan is 6 hours; if the wafer removal rate after polishing for the fourth time period deviates from the previous time period, the lifespan is 8 hours; if the wafer removal rate after polishing for the fifth time period deviates from the previous time period, the lifespan is 10 hours. The specific test results are shown in Table 1; Table 1

[0056] A comparison of Example 1 and Comparative Example 2 shows that surfactants can be adsorbed on the surface of abrasive particles, preventing particle agglomeration through electrostatic repulsion or steric hindrance, ensuring uniform suspension of each component, improving the stability of the wafer polishing slurry, and thus improving the polishing effect.

[0057] (2) Method for detecting wafer polishing effect: Use a strong light halogen lamp and metallographic microscope to observe surface scratches, and use AFM (atomic force microscope) to detect the RA value (surface roughness) of the wafer surface. Method for detecting wafer removal rate: The density ρ of the silicon carbide wafer is 3.2 g / cm³. 3 The radius r of the wafer was measured, and the wafer mass was recorded as m1. The wafer was polished using the wafer polishing slurry of the examples and comparative examples. The polishing time t was recorded, and the wafer mass after polishing was recorded as m2. The removal rate = (m1-m2) / (ρ×π×r) 2 ×t); The specific test results are shown in Table 2; Table 2

[0058] Figure 1 and Figure 2 The comparison shows that the silicon carbide surface polished by the wafer polishing slurry in the embodiment is smoother and more even.

[0059] Comparing Example 1 and Comparative Example 1, it can be seen that the oxidant can preferentially react with the atoms on the wafer surface to transform the difficult-to-process substrate into an oxide product with lower hardness and a looser structure. The abrasive removes the softened oxide product and removes the residual micro-damage layer on the wafer surface, which avoids scratches caused by the adhesion of oxide products and reduces the mechanical damage to the wafer surface caused by a single abrasive.

[0060] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A wafer polishing slurry, characterized in that, The wafer polishing fluid includes abrasives, oxidants, dispersants, surfactants, pH adjusters, and water.

2. The wafer polishing slurry according to claim 1, characterized in that, By weight, the wafer polishing slurry includes: 5-15 parts by weight of abrasive; 2 to 8 parts by weight of oxidant; 2-6 parts by weight of dispersant; 2 to 5 parts by weight of surfactant; The remaining part is water; The pH of the wafer polishing solution is 1.5-3.

5.

3. The wafer polishing slurry according to claim 2, characterized in that, By weight, the wafer polishing slurry includes: 5-10 parts by weight of abrasive; 4-6 parts by weight of oxidant; 3-5 parts by weight of dispersant; 2 to 4 parts by weight of surfactant; The pH of the wafer polishing solution is 1.7-2.5; The remaining part is water.

4. The wafer polishing slurry according to any one of claims 1-3, characterized in that, The abrasive has an average particle size of 30 nm to 1 μm. And / or, the abrasive includes at least one of alumina, zirconium oxide, silicon carbide, silicon oxide, and manganese oxide; And / or, the surfactant includes at least one of cationic surfactants, anionic surfactants, amphoteric surfactants, and nonionic surfactants.

5. The wafer polishing slurry according to claim 4, characterized in that, The average particle size of the abrasive is 40-200 nm; And / or, the abrasive is a mixture of alumina and silicon dioxide in a mass ratio of 7:3; And / or, the cationic surfactant includes at least one of dodecyltrimethylammonium chloride and hexadecyltrimethylammonium bromide; And / or, the anionic surfactant includes at least one of sodium alkylbenzene sulfonate and sodium alkyl sulfate, optionally including sodium dodecylbenzene sulfonate and / or sodium dodecyl sulfate; And / or, the amphoteric surfactant includes at least one of imidazoline derivatives, amino acid types, and lecithin; And / or, the nonionic surfactant includes at least one of glycerol fatty acid esters, sorbitol fatty acid esters, and fatty alcohol polyoxyethylene ethers.

6. A method for preparing the wafer polishing slurry according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: mixing the components to obtain a wafer polishing slurry.

7. The preparation method according to claim 6, characterized in that, The mixing is carried out by stirring; Optionally, the stirring conditions include: a rotation speed of 100-300 r / min, a temperature of 20-30℃, and a time of 10-30 min.

8. The preparation method according to claim 7, characterized in that, The stirring conditions include: a rotation speed of 250-280 r / min, a temperature of 20-25℃, and a time of 20-30 min.

9. The preparation method according to any one of claims 6-8, characterized in that, The preparation method includes the following steps: S1, mix the oxidant with water to obtain mixed solution A; S2, the abrasive is mixed with the mixed solution A to obtain mixed solution B; S3, mix the dispersant with the mixed solution B to obtain mixed solution C; S4, the surfactant is mixed with the mixed solution C to obtain mixed solution D; S5, mix the pH adjuster with the mixed solution D to obtain the wafer polishing solution.

10. The use of the wafer polishing slurry according to any one of claims 1-5 or the wafer polishing slurry prepared by the preparation method according to claims 6-9 in polishing wafers.

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