A large-size silicon wafer cmp polishing liquid composition, a preparation method and application thereof

Abstract

The application discloses a preparation method of a large-size silicon wafer CMP polishing liquid composition and application thereof. The polishing liquid is composed of raw materials in the following contents: modified silica sol abrasive 20-40%, alkaline compound (rate accelerator) 1.5-5.0%, pH value stabilizer 0.5-5.0%, compounded antioxidant additive 0.05-0.5%, lubricant 0.01-0.1%, defoaming agent 0.001-0.1%, and the rest is deionized water. The pH value of the polishing liquid is 11.5-12.0. The CMP polishing liquid composition solves the problems of easy yellowing, quick aging, short service life of the polishing pad and glazing of the polishing pad caused by easy agglomeration and deposition of the silica sol in the existing large-size silicon wafer CMP polishing, and overcomes the defects that the existing formula can only optimize the polishing rate and surface quality and cannot simultaneously inhibit oxidation, abrasion resistance and dispersion stability of the polishing pad.

Description

Technical Field

[0001] This invention belongs to the field of chemical mechanical polishing technology for semiconductor materials, specifically relating to a CMP polishing slurry composition for large-size silicon wafers, its preparation method, and its application. Background Technology

[0002] Semiconductors are the core of the information technology industry. Silicon wafers are the most important basic material in the semiconductor industry and the cornerstone of integrated circuits. Applications require them to have atomic-level surface precision and nanometer-level surface accuracy. Chemical mechanical polishing (CMP) is a core key process for achieving global planarization of large-size silicon wafers. It achieves atomic-level planarization of the silicon wafer surface through the dual coupling effect of oxidation and corrosion by chemical reagents in the polishing slurry and mechanical grinding by nano-abrasive particles. This directly determines the surface quality, processing precision, and performance and yield of subsequent devices, making it an indispensable core link in the mass production of large-size silicon wafers. With the rapid development of the semiconductor industry towards high integration and high computing power, the demand for large-size silicon wafers (such as 300mm and above) is surging, placing higher demands on the stability, efficiency, and economy of the CMP polishing process. Among these, the performance of the polishing slurry composition and the lifespan of the polishing pad have become key factors restricting process costs and production efficiency.

[0003] CMP polishing slurry, as a core consumable in the process, typically consists of abrasives, buffer solutions, polishing agents, and various additives. Among these, abrasives, as the core component of mechanical grinding, directly affect grinding efficiency and surface defect control. Silica sol, due to its advantages such as uniform particle size, good dispersibility, and minimal grinding damage, has become one of the most widely used abrasives in CMP polishing slurries for large-size silicon wafers. However, traditional silica sol abrasives suffer from problems such as high surface activity and insufficient dispersion stability, making them prone to agglomeration during polishing. This not only leads to defects such as scratches and dents on the silicon wafer surface but also exacerbates wear and contamination on the polishing pad surface. Furthermore, traditional polishing slurry formulations lack targeted functional components, making it difficult to address industry pain points such as yellowing and rapid aging of polishing pads during the polishing process. Polishing pads are key consumables in CMP processes, responsible for carrying polishing slurry, transmitting mechanical forces, and controlling surface morphology. Their performance and service life directly affect the stability of the polishing process and production costs. They account for about one-third of the total cost of CMP and are extremely technically complex. They must simultaneously possess good rigidity, corrosion resistance, wear resistance, and hydrophilicity to achieve effective storage and transportation of polishing slurry, stable transmission of polishing pressure, and timely discharge of polishing waste. During the CMP polishing process of large-size silicon wafers, due to the high polishing pressure and long polishing time, the oxidants, abrasives, and silicon wafer debris generated in the polishing slurry continuously act on the surface of the polishing pad. On the one hand, the oxidants in the polishing slurry (such as hydrogen peroxide) will cause oxidation and corrosion to the polyurethane and other substrates on the surface of the polishing pad, resulting in yellowing and deformation of the microporous layer on the surface of the polishing pad and a decrease in elastic modulus, i.e., the "pad yellowing" phenomenon. On the other hand, abrasive agglomerates and silicon debris will aggravate the mechanical wear on the surface of the polishing pad, block the micropores of the polishing pad, and cause the surface of the polishing pad to glaze and reduce its support capacity, further shortening the service life of the polishing pad, increasing the frequency of consumable replacement and production costs in the production process. At the same time, frequent replacement of polishing pads will also affect the continuity of production, reduce production efficiency, and even cause poor silicon wafer polishing consistency due to the instability of polishing pad performance, affecting product yield.

[0004] Currently, research and development of CMP polishing slurries for large-size silicon wafers mainly focuses on optimizing abrasive particle size, improving polishing rate, and reducing silicon wafer surface defects, while paying insufficient attention to the problems of polishing pad yellowing and short lifespan. Some polishing slurry formulations have attempted to add single types of additives to improve polishing pad performance, but the effects are limited: adding lubricants alone can reduce friction and wear between the polishing pad and the silicon wafer to some extent, but it cannot inhibit the oxidation and yellowing of the polishing pad; adding antioxidants alone can alleviate oxidation corrosion, but it is difficult to solve the mechanical wear and micropore blockage problems caused by abrasive agglomeration; at the same time, traditional unmodified silica sol abrasives have poor dispersion stability and prominent agglomeration, further aggravating polishing pad damage, failing to fundamentally solve the core pain points of polishing pad yellowing and short lifespan, and making it difficult to meet the demands of large-scale, low-cost, and high-quality production of large-size silicon wafers. Furthermore, as the semiconductor industry's requirements for production efficiency and cost control continue to increase, extending polishing pad lifespan and reducing consumable consumption have become urgent needs for industry development. The limitations of existing polishing slurry formulations make them unsuitable for the demanding conditions of CMP polishing of large-size silicon wafers, and they cannot balance the polishing quality of silicon wafers with the lifespan of polishing pads. Therefore, developing a CMP polishing slurry composition and its preparation method that can effectively prevent polishing pads from yellowing, significantly extend the lifespan of polishing pads, and at the same time ensure the polishing quality and efficiency of large-size silicon wafers has become an urgent technical problem to be solved in the current semiconductor consumables field, and has important industrial application value and practical significance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a CMP polishing slurry composition for large-size silicon wafers. This CMP polishing slurry composition solves the problems caused by traditional polishing slurries in the CMP polishing of large-size silicon wafers, such as yellowing of polishing pads, rapid aging, short lifespan, and glazing of polishing pads due to easy aggregation and deposition of silica sol. It overcomes the shortcomings of existing formulations that only optimize polishing rate and surface quality, and cannot simultaneously inhibit polishing pad oxidation, resist wear, and stabilize dispersion. This invention develops a CMP polishing slurry composition that can ensure high-precision polishing quality and efficiency of silicon wafers, significantly extend the lifespan of polishing pads, and reduce production costs, meeting the needs of the semiconductor industry for efficient, low-cost, and large-scale production.

[0006] The present invention also provides a method for preparing and applying the above-mentioned CMP polishing slurry composition for large-size silicon wafers.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A CMP polishing slurry composition for large-size silicon wafers, wherein the polishing slurry composition comprises the following raw materials in weight percentages: Modified silica sol abrasive: 20%-40%, Basic compounds (rate accelerators): 1.5%-5.0%, pH stabilizer: 0.5%-5.0%, Compound antioxidant additives: 0.05%-0.5%, Lubricant: 0.01%-0.1%, Defoamer: 0.001%-0.1%, The remainder is deionized water; and the pH value of the polishing solution composition is 11.5-12.0.

[0008] Specifically, there are no significant limitations on the properties and shape of the modified silica sol abrasive. The particle size of the modified silica sol abrasive is 20-150 nm. The modified silica sol abrasive is nanoparticles with amino groups on the surface after modification with a silane coupling agent. The silane coupling agent may include at least one of 3-aminopropyltriethoxysilane (KH550) and 3-aminopropyltrimethoxysilane (KH540). Preferably, 3-aminopropyltriethoxysilane (KH550) is a reagent with a mild reaction rate.

[0009] Specifically, the alkaline compound has the function of increasing the material removal rate and can be at least one of inorganic alkali metal hydroxides, organic quaternary ammonium strong base compounds, etc.; the inorganic alkali metal hydroxides include at least one of inorganic strong bases such as potassium hydroxide and sodium hydroxide; the organic quaternary ammonium strong base compounds are such as quaternary ammonium hydroxides. Specific examples of quaternary ammonium hydroxides include one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, and tetrahexylammonium hydroxide. Among them, tetraalkylammonium hydroxide is preferred, and tetramethylammonium hydroxide (TMAH) is more preferred.

[0010] Specifically, the pH stabilizer is used to maintain the pH value of the polishing slurry during use, enabling the slurry to have a high and continuous material removal rate, and is an indispensable component of the polishing slurry. The pH stabilizer can be one or more of the following: weak base salts or organic weak bases, such as potassium carbonate, sodium carbonate, carboxylates (such as sodium acetate, sodium citrate, etc.), piperazine, pyridine, amine compounds (such as ethylenediamine, etc.), and basic amino acid salts (such as sodium glycine, etc.).

[0011] Specifically, the compound antioxidant additive is used to prevent the polishing pad from being oxidized and thermally degraded by oxygen free radicals under high temperature and mechanical friction during polishing, thereby extending the yellowing time of the polishing pad and improving its service life. The compound antioxidant additive can be composed of a primary antioxidant and an auxiliary antioxidant in a mass ratio of 2:1 to 1:3.

[0012] Furthermore, the primary antioxidant includes at least one water-soluble hindered phenol, such as Irganox 245-DW, KY-616-3, etc. Irganox 245-DW is preferred.

[0013] Furthermore, the auxiliary antioxidants include phosphites and thioethers, such as one or more of antioxidant 168 (tris(2,4-di-tert-butylphenyl) phosphite), antioxidant 618 (triphenyl phosphite), antioxidant 3114 (pentaerythritol diphosphite), DLTDP (dilauryl thiodipropionate), and DSTDP (distearate thiodipropionate).

[0014] Specifically, the lubricant includes one or more of polysorbate (Tween), fatty alcohol polyoxyethylene ether (AEO-9), alkylphenol polyoxyethylene ether (OP), and polyvinyl alcohol (PVA); the defoamer is an organosilicone defoamer.

[0015] Accordingly, the present invention provides a method for preparing the above-mentioned large-size silicon wafer CMP polishing slurry composition, which includes the following steps: S1: Coupling agent pre-hydrolysis: Mix the coupling agent, anhydrous ethanol, and water at a mass ratio of 1:15-25:15-25, and sonicate for 20-50 minutes to obtain a fully hydrolyzed coupling agent system; the amount of coupling agent added accounts for 0.3-0.9% of the silica sol mass; S2: Silica sol modification. Take a certain amount of silica sol, keep it in a water bath at 50-70℃ for 15-30 minutes, add the coupling agent system prepared by S1 dropwise, stir and react for 1-2 hours. After the reaction is completed, filter to obtain modified silica sol abrasive. S3: Weigh out the alkaline compound and pH stabilizer, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive and mix thoroughly; S5: Add the compound antioxidant additive and lubricant to the remaining deionized water and mix well; S6: Mix the product obtained in S4, the defoamer, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing liquid composition with a pH value of 11.5-12.0.

[0016] The present invention also provides the application of the above-mentioned large-size silicon wafer CMP polishing slurry composition in the manufacturing of high-precision optical devices and integrated circuits, such as its application in the precision polishing of silicon substrate wafers or epitaxial wafers.

[0017] The large-size silicon wafer CMP polishing slurry composition of the present invention can be diluted 10-40 times before use and can be used for precision polishing of silicon substrates or epitaxial wafers.

[0018] This invention relates to a large-size silicon wafer CMP polishing slurry composition. Through innovative formulation design and preparation process, it solves the core pain points in large-size silicon wafer CMP polishing, such as polishing pad yellowing, rapid aging, short lifespan, and glazing caused by abrasive agglomeration. It achieves synergistic optimization of high-precision silicon wafer polishing and long polishing pad lifespan. This large-size silicon wafer CMP polishing slurry composition can be used in precision polishing of silicon substrates or epitaxial wafers, and can also be extended to other related precision processing applications.

[0019] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1) The large-size silicon wafer CMP polishing slurry composition of the present invention, with its compounded antioxidant additives, can effectively inhibit the oxidation and thermal degradation of the polishing pad caused by oxygen free radicals due to high temperature, mechanical friction, and oxidants (such as hydrogen peroxide) in the polishing slurry during the polishing process. This delays the glazing and yellowing of the polishing pad, and prevents the clogging of micropores on the polishing pad surface and a decrease in elastic modulus. Combined with the introduction of lubricant, it significantly extends the yellowing time of the polishing pad and improves its lifespan. This greatly reduces the production cost of large-size silicon wafer mass production.

[0020] 2) The large-size silicon wafer CMP polishing slurry composition of the present invention uses modified silica sol abrasive, which overcomes the problems of unstable polishing slurry products and particle deposition on polishing pads caused by the agglomeration of silica sol particles at high salt concentrations, improves the performance of the polishing slurry, and significantly extends the service life of the polishing pad.

[0021] 3) The CMP polishing slurry composition for large-size silicon wafers of the present invention has a simple and controllable preparation process. The modified silica sol abrasive and lubricant can stabilize the silica sol particles and achieve sub-nanometer surface roughness. It is an ideal polishing slurry material for sub-nanometer smoothness in the manufacture of semiconductor compound wafers. Attached Figure Description

[0022] Figure 1 The color of the polishing pad after 2 hours of using a conventional large-size silicon wafer CMP polishing slurry composition.

[0023] Figure 2 The color of the polishing pad after 12 hours of use of a CMP polishing slurry composition for large-size silicon wafers containing modified silica sol abrasive compounded with antioxidant additives. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.

[0025] In the following examples, all raw materials used were commercially available products that could be purchased directly. The silica sol was purchased from Shandong Baite New Materials Co., Ltd., model NK100. The defoamer was preferably an organosilicon defoamer, such as BYK028 (BYK Chemical) and DF689 (Guanzhi Chemical). Other reagents were all analytical grade and purchased from Sinopharm. Example 1

[0026] A CMP polishing slurry composition for large-size silicon wafers, the slurry comprising the following raw materials in weight percentage: 25% modified silica sol abrasive, 2% alkaline compound (rate accelerator) tetramethylammonium hydroxide, 3% pH stabilizer piperazine, 0.2% compound antioxidant additive (composed of water-soluble hindered phenolic primary antioxidant Irganox 245-DW and thioether auxiliary antioxidant DLTDP in a 1:1 mass ratio), 0.05% lubricant AEO-9, 0.05% defoamer BYK028; the balance being deionized water.

[0027] The preparation method of the above-mentioned CMP polishing slurry composition for large-size silicon wafers is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification: Weigh silica sol and add it to a three-necked flask. Insert a polytetrafluoroethylene stir bar and a spherical condenser. After maintaining the temperature in a water bath at 60℃ for 20 minutes, slowly add the fully hydrolyzed coupling agent system prepared in S1 to the silica sol system. Stir for 1 hour to allow for a complete reaction. After the reaction is complete, filter the mixture using a 10µm filter cartridge and bottle it to obtain modified silica sol abrasive (i.e., silica sol dispersion modified with silane coupling agent). S3: Weigh out the alkaline compound tetramethylammonium hydroxide and the pH stabilizer piperazine, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out the compound antioxidant additive consisting of Irganox 245-DW, a water-soluble hindered phenolic main antioxidant with a mass ratio of 1:1, and DLTDP (dilauryl thiodipropionate), a thioether auxiliary antioxidant, and add lubricant AEO-9 to the remaining deionized water and mix well. S6: Mix the product obtained in S4, the defoamer BYK028, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing liquid composition with a pH value of 11.8. Example 2

[0028] A CMP polishing slurry composition for large-size silicon wafers, the polishing slurry comprising the following raw materials by weight percentage: 30% modified silica sol abrasive, 2% alkaline compound (rate accelerator) potassium hydroxide, 3% pH stabilizer piperazine, 0.3% compound antioxidant additive (composed of water-soluble hindered phenolic primary antioxidant Irganox 245-DW and phosphite auxiliary antioxidant 168 in a mass ratio of 2:1), 0.08% lubricant Tween 20, 0.05% defoamer DF689; the balance being deionized water.

[0029] The preparation method of the above-mentioned CMP polishing slurry composition for large-size silicon wafers is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification: Weigh silica sol and add it to a three-necked flask. Insert a polytetrafluoroethylene stir bar and a spherical condenser. After maintaining the temperature in a water bath at 60℃ for 20 minutes, slowly add the fully hydrolyzed coupling agent system prepared in S1 to the silica sol system. Stir for 1 hour to allow for a complete reaction. After the reaction is complete, filter the mixture using a 10µm filter cartridge and bottle it to obtain modified silica sol abrasive (i.e., silica sol dispersion modified with silane coupling agent). S3: Weigh out the alkaline compound potassium hydroxide and the pH stabilizer piperazine, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out the compound antioxidant additive consisting of water-soluble hindered phenolic main antioxidant Irganox 245-DW and phosphite auxiliary antioxidant 168 in a mass ratio of 2:1, add lubricant Tween 20 to the remaining deionized water, and mix well. S6: Mix the product obtained in S4, the defoamer DF689, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing liquid composition with a pH value of 11.6. Example 3

[0030] A CMP polishing slurry composition for large-size silicon wafers, the slurry comprising the following raw materials by weight percentage: 28% modified silica sol abrasive, 2% potassium hydroxide (a basic compound / rate accelerator), 2% potassium carbonate (a pH stabilizer), 0.4% compound antioxidant additive (composed of Irganox 245-DW, a water-soluble hindered phenolic primary antioxidant, and DLTDP, a thioether-based auxiliary antioxidant, in a 1:1 mass ratio), 0.07% PVA lubricant, and 0.05% defoamer BYK028; the balance being deionized water.

[0031] The preparation method of the above-mentioned CMP polishing slurry composition for large-size silicon wafers is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Silica sol was weighed and added to a three-necked flask. A polytetrafluoroethylene (PTFE) stir bar and a spherical condenser were inserted. After incubation at 60°C for 20 minutes in a water bath, the fully hydrolyzed coupling agent system prepared in S1 was slowly added dropwise to the silica sol system. The mixture was stirred for 1 hour to allow for a complete reaction. After the reaction was complete, the mixture was filtered using a 10µm filter and bottled to obtain modified silica sol abrasive (i.e., silane coupling agent modified silica sol dispersion). S3: Weigh out the alkaline compound potassium hydroxide and the pH stabilizer potassium carbonate, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out the compound antioxidant additive consisting of Irganox 245-DW, a water-soluble hindered phenolic main antioxidant with a mass ratio of 1:1, and DLTDP (dilauryl thiodipropionate), a thioether auxiliary antioxidant, and add lubricant PVA to the remaining deionized water and mix well. S6: Mix the product obtained in S4, the defoamer BYK028, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing liquid composition with a pH value of 11.5. Example 4

[0032] A CMP polishing slurry composition for large-size silicon wafers, the polishing slurry comprising the following raw materials in weight percentage: 35% modified silica sol abrasive, 2% alkaline compound (rate accelerator) tetramethylammonium hydroxide, 3% pH stabilizer piperazine, 0.1% compound antioxidant additive (composed of water-soluble hindered phenolic primary antioxidant Irganox 245-DW and phosphite auxiliary antioxidant 168 in a mass ratio of 1:2), 0.06% lubricant OP, 0.05% defoamer DF689; the balance being deionized water.

[0033] The preparation method of the above-mentioned CMP polishing slurry composition for large-size silicon wafers is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Silica sol was weighed and added to a three-necked flask. A polytetrafluoroethylene (PTFE) stir bar and a spherical condenser were inserted. After incubation at 60°C for 20 minutes in a water bath, the fully hydrolyzed coupling agent system prepared in S1 was slowly added dropwise to the silica sol system. The mixture was stirred for 1 hour to allow for a complete reaction. After the reaction was complete, the mixture was filtered using a 10µm filter and bottled to obtain modified silica sol abrasive (i.e., silane coupling agent modified silica sol dispersion). S3: Weigh out the alkaline compound tetramethylammonium hydroxide and the pH stabilizer piperazine, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out the compound antioxidant additive consisting of water-soluble hindered phenolic main antioxidant Irganox 245-DW and phosphite auxiliary antioxidant 168 in a mass ratio of 1:2, add lubricant OP to the remaining deionized water, and mix well. S6: Mix the product obtained in S4, the defoamer DF689, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing liquid composition with a pH value of 11.7. Example 5

[0034] A CMP polishing slurry composition for large-size silicon wafers, the slurry comprising the following raw materials in weight percentage: 20% modified silica sol abrasive, 2% alkaline compound (rate accelerator, composed of water-soluble hindered phenolic primary antioxidant Irganox 245-DW and thioether-based auxiliary antioxidant DLTDP in a mass ratio of 1:1), 3% pH stabilizer ethylenediamine, 0.3% compound antioxidant additive (composed of water-soluble hindered phenolic primary antioxidant Irganox 245-DW and thioether-based auxiliary antioxidant DLTDP in a mass ratio of 1:1), 0.04% lubricant AEO-9, 0.05% defoamer BYK028; the balance being deionized water.

[0035] The preparation method of the above-mentioned CMP polishing slurry composition for large-size silicon wafers is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Silica sol was weighed and added to a three-necked flask. A polytetrafluoroethylene (PTFE) stir bar and a spherical condenser were inserted. After incubation at 60°C for 20 minutes in a water bath, the fully hydrolyzed coupling agent system prepared in S1 was slowly added dropwise to the silica sol system. The mixture was stirred for 1 hour to allow for a complete reaction. After the reaction was complete, the mixture was filtered using a 10µm filter and bottled to obtain modified silica sol abrasive (i.e., silane coupling agent modified silica sol dispersion). S3: Weigh out the alkaline compound composed of tetramethylammonium hydroxide and potassium hydroxide in a mass ratio of 1:1, and the pH stabilizer ethylenediamine, add them to a portion of deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out the compound antioxidant additive consisting of Irganox 245-DW, a water-soluble hindered phenolic main antioxidant with a mass ratio of 1:1, and DLTDP (dilauryl thiodipropionate), a thioether auxiliary antioxidant, and add lubricant AEO-9 to the remaining deionized water and mix well. S6: Mix the product obtained in S4, the defoamer BYK028, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing liquid composition with a pH value of 11.7. Example 6

[0036] A CMP polishing slurry composition for large-size silicon wafers, the polishing slurry comprising the following raw materials by weight percentage: 30% modified silica sol abrasive, 2% alkaline compound (rate accelerator) tetramethylammonium hydroxide, 3% pH stabilizer piperazine, 0.3% compound antioxidant additive (composed of water-soluble hindered phenolic primary antioxidant KY-616-3 and thioether auxiliary antioxidant DSTDP in a 1:1 mass ratio), 0.02% lubricant AEO-9, 0.05% defoamer BYK028; the balance being deionized water.

[0037] The preparation method of the above-mentioned CMP polishing slurry composition for large-size silicon wafers is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Silica sol was weighed and added to a three-necked flask. A polytetrafluoroethylene (PTFE) stir bar and a spherical condenser were inserted. After incubation at 60°C for 20 minutes in a water bath, the fully hydrolyzed coupling agent system prepared in S1 was slowly added dropwise to the silica sol system. The mixture was stirred for 1 hour to allow for a complete reaction. After the reaction was complete, the mixture was filtered using a 10µm filter and bottled to obtain modified silica sol abrasive (i.e., silane coupling agent modified silica sol dispersion). S3: Weigh out the alkaline compound tetramethylammonium hydroxide and the pH stabilizer piperazine, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out the compound antioxidant additive composed of water-soluble hindered phenolic main antioxidant KY-616-3 and thioether auxiliary antioxidant DSTDP (distearate thiodipropionate) in a mass ratio of 1:1, and lubricant AEO-9, and add them to the remaining deionized water and mix well. S6: Mix the product obtained in S4, the defoamer BYK028, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing liquid composition with a pH value of 11.9. Example 7

[0038] A CMP polishing slurry composition for large-size silicon wafers, the polishing slurry comprising the following raw materials in weight percentage: 35% modified silica sol abrasive, 3% alkaline compound (rate accelerator) tetramethylammonium hydroxide, 3% pH stabilizer (composed of potassium carbonate and piperazine in a 1:1 mass ratio), 0.4% compound antioxidant additive (composed of water-soluble hindered phenolic primary antioxidant KY-616-3 and phosphite auxiliary antioxidant 168 in a 1:3 mass ratio), 0.08% lubricant AEO-9, 0.05% defoamer DF689; the balance being deionized water.

[0039] The preparation method of the above-mentioned CMP polishing slurry composition for large-size silicon wafers is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Silica sol was weighed and added to a three-necked flask. A polytetrafluoroethylene (PTFE) stir bar and a spherical condenser were inserted. After incubation at 60°C for 20 minutes in a water bath, the fully hydrolyzed coupling agent system prepared in S1 was slowly added dropwise to the silica sol system. The mixture was stirred for 1 hour to allow for a complete reaction. After the reaction was complete, the mixture was filtered using a 10µm filter and bottled to obtain modified silica sol abrasive (i.e., silane coupling agent modified silica sol dispersion). S3: Weigh out the alkaline compound tetramethylammonium hydroxide and the pH stabilizer composed of potassium carbonate and piperazine in a 1:1 mass ratio, add them to a portion of deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out the compound antioxidant additive consisting of water-soluble hindered phenolic main antioxidant KY-616-3 and phosphite auxiliary antioxidant 168 in a mass ratio of 1:3, and lubricant AEO-9, and add them to the remaining deionized water and mix well. S6: Mix the product obtained in S4, the defoamer DF689, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing liquid composition with a pH value of 11.8. Example 8

[0040] A CMP polishing slurry composition for large-size silicon wafers, the slurry comprising the following raw materials by weight percentage: 25% modified silica sol abrasive, 2% alkaline compound (rate accelerator) tetramethylammonium hydroxide, 3% pH stabilizer piperazine, 0.2% compound antioxidant additive (composed of water-soluble hindered phenolic primary antioxidant Irganox 245-DW and thioether auxiliary antioxidant DLTDP in a 1:1 mass ratio), 0.08% lubricant AEO-9, 0.05% defoamer BYK028; the balance being deionized water.

[0041] The preparation method of the above-mentioned CMP polishing slurry composition for large-size silicon wafers is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the coupling agent KH540 by mass of silica sol, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Silica sol was weighed and added to a three-necked flask. A polytetrafluoroethylene (PTFE) stir bar and a spherical condenser were inserted. After incubation at 60°C for 20 minutes in a water bath, the fully hydrolyzed coupling agent system prepared in S1 was slowly added dropwise to the silica sol system. The mixture was stirred for 1 hour to allow for a complete reaction. After the reaction was complete, the mixture was filtered using a 10µm filter and bottled to obtain modified silica sol abrasive (i.e., silane coupling agent modified silica sol dispersion). S3: Weigh out the alkaline compound tetramethylammonium hydroxide and the pH stabilizer piperazine, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out the compound antioxidant additive consisting of Irganox 245-DW, a water-soluble hindered phenolic main antioxidant with a mass ratio of 1:1, and DLTDP (dilauryl thiodipropionate), a thioether auxiliary antioxidant, and add lubricant AEO-9 to the remaining deionized water and mix well. S6: Mix the product obtained in S4, the defoamer BYK028, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing liquid composition with a pH value of 11.8.

[0042] Comparative Example 1 A conventional large-size silicon wafer CMP polishing slurry composition, wherein the polishing slurry is composed of the following raw materials in weight percentage: 25% modified silica sol abrasive, 2% alkaline compound (rate accelerator) tetramethylammonium hydroxide, 3% pH stabilizer piperazine, 0.05% lubricant AEO-9, 0.05% defoamer BYK028; the balance being deionized water.

[0043] The preparation method of the above-mentioned conventional large-size silicon wafer CMP polishing slurry composition is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Silica sol was weighed and added to a three-necked flask. A polytetrafluoroethylene (PTFE) stir bar and a spherical condenser were inserted. After incubation at 60°C for 20 minutes in a water bath, the fully hydrolyzed coupling agent system prepared in S1 was slowly added dropwise to the silica sol system. The mixture was stirred for 1 hour to allow for a complete reaction. After the reaction was complete, the mixture was filtered using a 10µm filter and bottled to obtain modified silica sol abrasive (i.e., silane coupling agent modified silica sol dispersion). S3: Weigh out the alkaline compound tetramethylammonium hydroxide and the pH stabilizer piperazine, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out lubricant AEO-9 and add it to the remaining deionized water, then mix well; S6: Mix the product obtained in S4, the defoamer BYK028, and the product obtained in S5 evenly to obtain the conventional large-size silicon wafer CMP polishing liquid composition with a pH value of 11.9.

[0044] Comparative Example 2 A conventional large-size silicon wafer CMP polishing slurry composition, wherein the polishing slurry is composed of the following raw materials in weight percentage: 25% modified silica sol abrasive, 2% alkaline compound (rate accelerator) tetramethylammonium hydroxide, 2% pH stabilizer potassium carbonate, 0.05% lubricant AEO-9, 0.05% defoamer BYK028; the balance being deionized water.

[0045] The preparation method of the above-mentioned conventional large-size silicon wafer CMP polishing slurry composition is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Silica sol was weighed and added to a three-necked flask. A polytetrafluoroethylene (PTFE) stir bar and a spherical condenser were inserted. After incubation at 60°C for 20 minutes in a water bath, the fully hydrolyzed coupling agent system prepared in S1 was slowly added dropwise to the silica sol system. The mixture was stirred for 1 hour to allow for a complete reaction. After the reaction was complete, the mixture was filtered using a 10µm filter and bottled to obtain modified silica sol abrasive (i.e., silane coupling agent modified silica sol dispersion). S3: Weigh out the alkaline compound tetramethylammonium hydroxide and the pH stabilizer potassium carbonate, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out lubricant AEO-9 and add it to the remaining deionized water, then mix well; S6: Mix the product obtained in S4, the defoamer BYK028, and the product obtained in S5 evenly to obtain the conventional large-size silicon wafer CMP polishing fluid composition with a pH value of 11.5.

[0046] Comparative Example 3 A conventional large-size silicon wafer CMP polishing slurry composition, wherein the polishing slurry is composed of the following raw materials in weight percentage: 25% modified silica sol abrasive, 2% alkaline compound (rate accelerator) tetramethylammonium hydroxide, 3% pH stabilizer piperazine, 0.2% compound antioxidant additive (composed of water-soluble hindered phenolic primary antioxidant Irganox 245-DW and thioether auxiliary antioxidant DLTDP in a mass ratio of 1:4), 0.05% lubricant AEO-9, 0.05% defoamer BYK028; the balance being deionized water.

[0047] The preparation method of the above-mentioned conventional large-size silicon wafer CMP polishing slurry composition is as follows: S1: Coupling agent pre-hydrolysis: Weigh 0.5% of the silica sol mass of coupling agent KH550, mix the coupling agent, anhydrous ethanol and water in a mass ratio of 1:20:20, and sonicate for 30 minutes to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Silica sol was weighed and added to a three-necked flask. A polytetrafluoroethylene (PTFE) stir bar and a spherical condenser were inserted. After incubation at 60°C for 20 minutes in a water bath, the fully hydrolyzed coupling agent system prepared in S1 was slowly added dropwise to the silica sol system. The mixture was stirred for 1 hour to allow for a complete reaction. After the reaction was complete, the mixture was filtered using a 10µm filter and bottled to obtain modified silica sol abrasive (i.e., silane coupling agent modified silica sol dispersion). S3: Weigh out the alkaline compound tetramethylammonium hydroxide and the pH stabilizer piperazine, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive obtained in S2 and mix thoroughly; S5: Weigh out the compound antioxidant additive composed of Irganox 245-DW, a water-soluble hindered phenolic main antioxidant with a mass ratio of 1:4, and DLTDP (dilauryl thiodipropionate), a thioether auxiliary antioxidant, and add lubricant AEO-9 to the remaining deionized water and mix well. S6: Mix the product obtained in S4, the defoamer BYK028, and the product obtained in S5 evenly to obtain the conventional large-size silicon wafer CMP polishing fluid composition with a pH value of 11.8.

[0048] Comparative Example 4 A conventional large-size silicon wafer CMP polishing slurry composition, wherein the polishing slurry is composed of the following raw materials in weight percentage: 25% ordinary silica sol abrasive, 2% alkaline compound (rate accelerator) tetramethylammonium hydroxide, 3% pH stabilizer piperazine, 0.2% compound antioxidant additive (composed of water-soluble hindered phenolic primary antioxidant Irganox 245-DW and thioether auxiliary antioxidant DLTDP in a mass ratio of 1:1), 0.05% lubricant AEO-9, 0.05% defoamer BYK028; the balance being deionized water.

[0049] The preparation method of the above-mentioned conventional large-size silicon wafer CMP polishing slurry composition is as follows: S1: Weigh out ordinary silica sol and add it to part of deionized water; S2: Weigh out the alkaline compound tetramethylammonium hydroxide and the pH stabilizer piperazine, add them to part of the deionized water, and mix well; S3: Weigh out the compound antioxidant additive consisting of Irganox 245-DW, a water-soluble hindered phenolic main antioxidant with a mass ratio of 1:1, and DLTDP (dilauryl thiodipropionate), a thioether auxiliary antioxidant, and add lubricant AEO-9 to the remaining deionized water and mix well. S6: Mix the product obtained in S1, the product obtained in S2, the defoamer BYK028 and the product obtained in S3 evenly to obtain the conventional large-size silicon wafer CMP polishing liquid composition with a pH value of 11.7.

[0050] Performance testing The polishing slurries prepared in the above examples and comparative examples were subjected to polishing performance tests. The yellowing time of the polishing pads was recorded, and the material removal rate after 8 hours of polishing slurry circulation was evaluated.

[0051] The material removal rate test conditions are as follows. Polishing machine: Chuangji single-sided polishing machine. Polishing pad: Suba 800, Polishing target: 12-inch silicon substrate wafer Fixed plate speed: 40 rpm Disk rotation speed: 35 rpm Polishing slurry supply rate: 200 ml / min Usage: Dilute 30 times and reuse repeatedly.

[0052]

[0053] Figure 1 The color of the polishing pad after 2 hours of polishing with the conventional large-size silicon wafer CMP polishing slurry composition of Comparative Example 1 is shown. As can be seen from the figure, after 2 hours of polishing, the surface of the polishing pad is obviously yellow, indicating that its polymer material has undergone oxidation, resulting in a qualitative change in performance, which in turn directly leads to a significant impact on polishing efficiency.

[0054] Figure 2 The color of the polishing pad after 12 hours of polishing with the CMP polishing slurry composition containing modified silica sol abrasive compound antioxidant additives for large-size silicon wafers in Example 1 is shown in the figure. As can be seen from the figure, after 12 hours of polishing, there is no obvious yellowing or discoloration on the surface of the polishing pad, the overall color is uniform, and there are no signs of thermal aging or quality change of polymer materials, thus maintaining a high polishing efficiency.

[0055] As shown in Table 1, the polishing pad of Comparative Example 1 (without antioxidant additives) yellowed in only 2 hours, and the material removal rate decreased by as much as 50% after 8 hours. Comparative Example 2, also without antioxidant additives, yellowed in 3 hours with a decrease rate of 45%. Although Comparative Example 3 added a compound antioxidant, the mass ratio of the primary antioxidant to the secondary antioxidant was 1:4, and the yellowing time was only extended to 4 hours, with a decrease rate of 43%. In contrast, Examples 1-7 of this invention all used a compound of primary and secondary antioxidants (in a ratio of 2:1 to 1:3), and the yellowing time was significantly extended to 8-16 hours, with the decrease rate reduced to 3%-15%. This fully demonstrates the synergistic effect of the compound antioxidant additives, which can effectively inhibit the oxidation, yellowing, and thermal degradation of the polishing pad, thereby significantly extending the service life of the polishing pad and maintaining a stable material removal rate. Comparative Example 4 used unmodified ordinary silica sol abrasive. Although the ratio of compound antioxidants was the same as in Example 1, the yellowing time was only 1 hour, the decrease rate was as high as 50%, and the polishing slurry had poor storage stability. In contrast, Examples 1-8 all used silica sol abrasives modified with silane coupling agents (KH550 or KH540), and the yellowing time was ≥6 hours, with a significantly reduced degradation rate. This indicates that the surface amino-modified silica sol particles have excellent dispersion stability in a high-salt-alkaline environment, effectively avoiding abrasive agglomeration and deposition, thereby reducing clogging of the polishing pad's micropores and indirectly improving the polishing pad's durability. Example 3 (28% modified silica sol, KOH + potassium carbonate, Irganox 245-DW:DLTDP=1:1, PVA lubricant) performed best, with a yellowing time as long as 16 hours and a degradation rate of only 3%. Example 4, due to its lower antioxidant content (0.1%), had a relatively shorter yellowing time (8 hours) and a degradation rate of 15%, but it was still significantly better than all comparative examples. Example 8 used KH540 coupling agent in a 1:1 ratio, but the yellowing time was 6 hours and the degradation rate was 30%, slightly worse than the other examples. This may be related to the type of lubricant and process conditions, but it is still better than the comparative example. Overall, Examples 1-7 all achieved excellent anti-yellowing and low-efficiency degradation effects.

[0056] In summary, the large-size silicon wafer CMP polishing slurry composition of this invention, with its compounded antioxidant additives, effectively inhibits the oxidation and thermal degradation of the polishing pad caused by high temperatures, mechanical friction, and oxidants (such as hydrogen peroxide) in the polishing slurry during the polishing process. This delays the glazing and yellowing of the polishing pad, preventing the clogging of micropores on the polishing pad surface and a decrease in elastic modulus. Combined with the introduction of lubricant, it significantly extends the yellowing time of the polishing pad, improves its lifespan, and substantially reduces the production cost of large-size silicon wafer mass production. Simultaneously, the modified silica sol abrasive overcomes the problems of polishing slurry product instability and particle deposition on the polishing pad caused by the agglomeration of silica sol particles at high salt concentrations, improving the performance of the polishing slurry and significantly extending the lifespan of the polishing pad.

Claims

1. A CMP polishing slurry composition for large-size silicon wafers, characterized in that, The polishing fluid composition comprises the following raw materials in weight percentages: Modified silica sol abrasive: 20%-40%, Alkaline compounds: 1.5%-5.0%, pH stabilizer: 0.5%-5.0%, Compound antioxidant additives: 0.05%-0.5%, Lubricant: 0.01%-0.1%, Defoamer: 0.001%-0.1%, The remainder is deionized water; and the pH value of the polishing solution composition is 11.5-12.

0.

2. The CMP polishing slurry composition for large-size silicon wafers as described in claim 1, characterized in that, The modified silica sol abrasive has a particle size of 20-150 nm; the modified silica sol abrasive is a nanoparticle with amino groups on its surface after being modified by a silane coupling agent, and the silane coupling agent includes at least one of 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane.

3. The CMP polishing slurry composition for large-size silicon wafers as described in claim 1, characterized in that, The alkaline compound is at least one of inorganic alkali metal hydroxides and organic quaternary ammonium strong base compounds; the inorganic alkali metal hydroxides include at least one of potassium hydroxide and sodium hydroxide; the organic quaternary ammonium strong base compounds include one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, and tetrahexylammonium hydroxide.

4. The CMP polishing slurry composition for large-size silicon wafers as described in claim 1, characterized in that, The pH stabilizer is one or more of potassium carbonate, sodium carbonate, sodium acetate, sodium citrate, piperazine, pyridine, ethylenediamine, and sodium glycine.

5. The CMP polishing slurry composition for large-size silicon wafers as described in claim 1, characterized in that, The compound antioxidant additive consists of a primary antioxidant and a secondary antioxidant in a mass ratio of 2:1 to 1:

3.

6. The CMP polishing slurry composition for large-size silicon wafers as described in claim 1, characterized in that, The primary antioxidant includes at least one of Irganox 245-DW and KY-616-3.

7. The CMP polishing slurry composition for large-size silicon wafers as described in claim 1, characterized in that, The auxiliary antioxidants include one or more of antioxidant 168, antioxidant 618, antioxidant 3114, dilauryl thiodipropionate, and distearate thiodipropionate.

8. The CMP polishing slurry composition for large-size silicon wafers as described in claim 1, characterized in that, The lubricant includes one or more of polysorbate, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and polyvinyl alcohol; the defoamer is an organosilicone defoamer.

9. A method for preparing the CMP polishing slurry composition for large-size silicon wafers according to any one of claims 1-8, characterized in that, Includes the following steps: S1: Coupling agent pre-hydrolysis: The coupling agent, anhydrous ethanol and water are mixed in a mass ratio of 1:15-25:15-25 and ultrasonically treated to obtain a fully hydrolyzed coupling agent system. S2: Silica sol modification. Take a certain amount of silica sol, keep it in a water bath at 50-70℃ for 15-30 minutes, add the coupling agent system prepared by S1 dropwise, stir and react for 1-2 hours. After the reaction is completed, filter to obtain modified silica sol abrasive. S3: Weigh out the alkaline compound and pH stabilizer, add them to part of the deionized water, and mix well; S4: Add the mixture obtained in S3 to the modified silica sol abrasive and mix thoroughly; S5: Add the compound antioxidant additive and lubricant to the remaining deionized water and mix well; S6: Mix the product obtained in S4, the defoamer, and the product obtained in S5 evenly to obtain the large-size silicon wafer CMP polishing fluid composition.

10. The application of the large-size silicon wafer CMP polishing slurry composition as described in any one of claims 1-8 in the precision polishing of silicon substrates or epitaxial wafers, or in the manufacture of high-precision optical devices and integrated circuits.

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