A chemical mechanical polishing slurry, its preparation method and uses

Abstract

This invention discloses a chemical mechanical polishing (CMP) slurry. The raw materials of the CMP slurry include the following components: a water-soluble small molecule containing a morpholine ring, a water-soluble polymer with a main chain or side chain containing polyoxyethylene chains, an abrasive, an alkaline compound, and water. This technical solution can improve the edge collapse phenomenon of silicon wafers while achieving high flatness in the central region of the silicon wafer, thereby improving the overall surface flatness of the silicon wafer and meeting the needs of silicon wafer flatness in production.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor integrated circuit manufacturing, and in particular relates to a chemical mechanical polishing technology for silicon wafers. Background Technology

[0002] With the development of the integrated circuit industry, advanced manufacturing processes have placed higher demands on the surface flatness of silicon wafers. Techniques such as Chemical Mechanical Polishing (CMP) and Double-Side Polishing (DSP) can achieve high flatness of silicon wafers.

[0003] CMP (Chemical Mechanical Polishing) technology combines chemical and mechanical processes, offering advantages such as high processing speed, high polishing quality, and reliable results. However, during processing, the polishing rate at the edges of the silicon wafer is faster than in the center, leading to edge roll-off (ERO) at the outer periphery. This negatively impacts the quality and performance of subsequent processing steps. The CMP process is complex, influenced by numerous factors, including the type of workpiece surface material, the composition of the polishing slurry, and the pressure of the polishing head. While corresponding chemical mechanical polishing slurries have been developed to improve the edge roll-off problem, these slurries cannot effectively planarize the central region of the silicon wafer, resulting in poor overall wafer planarity.

[0004] Therefore, there is an urgent need for a technical solution that can effectively reduce the amount of edge collapse in the central region of silicon wafers, that is, improve the overall flatness of the silicon wafer surface. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a chemical mechanical polishing slurry and its preparation method that can improve the edge collapse phenomenon of silicon wafers while achieving high flatness of the central region of the silicon wafer, thereby improving the overall surface flatness of the silicon wafer. To achieve the above-mentioned object and other related objects, the present invention is obtained through the following technical solution.

[0006] The first aspect of this invention provides a chemical mechanical polishing fluid, the raw material components of which include: a water-soluble small molecule containing a morpholine ring; a water-soluble polymer with a main chain or side chain containing a polyoxyethylene chain; an abrasive; an alkaline compound; and water.

[0007] Chemical mechanical polishing of silicon wafers with polishing slurries containing water-soluble small molecules with morpholine rings and water-soluble polymers with polyoxyethylene chains in the main chain or side chain can improve the edge collapse phenomenon of silicon wafers and achieve high flatness in the central region of silicon wafers, thereby improving the overall surface flatness of silicon wafers.

[0008] According to the above-described chemical mechanical polishing fluid, the water-soluble small molecule containing a morpholine ring also has one or more of a phosphoroyl group, a carbonyl group, an ester group, an ether group, and an amide group.

[0009] According to the above-described chemical mechanical polishing fluid, the water-soluble small molecule containing a morpholine ring includes one or more of 2,2-dimorpholinodiethyl ether, tris(4-morpholino)phosphine oxide, and 4-(2-methoxyethyl)morpholine.

[0010] According to the above-described chemical mechanical polishing fluid, the polymer includes one or more of polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol, polyethylene glycol-polyvinyl alcohol graft copolymer, and hydroxyethyl cellulose.

[0011] Preferably, the number average molecular weight of the polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol is 2000-100000, such as 2000-4000, 4000-6000, 6000-8000, 8000-10000, 10000-20000, 20000-30000, 30000-40000, 40000-50000, 50000-60000, 60000-70000, 70000-80000, 80000-90000, 90000-100000, and in a specific embodiment, it is 8400. The molar ratio is 2:1 to 10:1, such as 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1; the number-average molecular weight is obtained by gel permeation chromatography (GPC).

[0012] Specifically, the structural diagram of the poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) is shown below:

[0013]

[0014] Where (x+z) ranges from 20 to 2000, and (x+z):y ranges from (2 to 10):1.

[0015] Preferably, the weight-average molecular weight of the hydroxyethyl cellulose is 100,000 to 1,300,000. For example, it can be 100,000 to 300,000, 300,000 to 500,000, 500,000 to 700,000, 700,000 to 900,000, 900,000 to 1,100,000, 1,100,000 to 1,300,000, 800,000, or 1,000,000. In a specific embodiment, it is 1,200,000. The weight-average molecular weight is obtained by GPC testing. Specifically, the structural schematic diagram of the hydroxyethyl cellulose is shown below:

[0016]

[0017] Where n is 50 to 5000 and x is 1 to 20.

[0018] Preferably, the number-average molecular weight of the polyethylene glycol-polyvinyl alcohol graft copolymer is 10,000 to 500,000, such as 10,000 to 50,000, 50,000 to 100,000, 100,000 to 150,000, 150,000 to 200,000, 200,000 to 250,000, 250,000 to 300,000, 300,000 to 350,000, 350,000 to 400,000, 400,000 to 450,000, or 450,000 to 500,000. The grafting rate of polyvinyl alcohol is 20% to 300%. The grafting rate is calculated using the weight gain method, with the formula G = (m1 / m0-1) × 100%, where G is the grafting rate, and m0 and m1 are the mass of polyethylene glycol and the mass of the graft copolymer, respectively. The number-average molecular weight is obtained by GPC testing.

[0019] Specifically, the structural schematic diagram of the polyethylene glycol-polyvinyl alcohol graft copolymer is shown below:

[0020]

[0021] Where (m+n) is 50 to 9000, and (m×p) is 30 to 9000.

[0022] In a specific embodiment, the polyethylene glycol-polyvinyl alcohol graft copolymer is produced by BASF. IR.

[0023] According to the aforementioned chemical mechanical polishing slurry, based on the total mass of the slurry, the amount of the water-soluble small molecule containing the morpholine ring is 0.005–0.5 wt%. Preferably, the amount can be 0.005–0.05 wt%, 0.05–0.1 wt%, 0.1–0.2 wt%, 0.2–0.3 wt%, 0.25–0.35 wt%, 0.3–0.4 wt%, 0.4–0.5 wt%, and in a specific embodiment, it is 0.3 wt%.

[0024] According to the aforementioned chemical mechanical polishing slurry, based on the total mass of the slurry, the amount of the polymer is 0.005–0.5 wt%. Preferably, the amount can be 0.005–0.05 wt%, 0.05–0.1 wt%, 0.1–0.2 wt%, 0.2–0.3 wt%, 0.3–0.4 wt%, or 0.3–0.5 wt%, and in a specific embodiment, it is 0.4 wt%.

[0025] Based on the aforementioned chemical mechanical polishing slurry, the amount of abrasive used is 1–40 wt% of the total mass of the slurry. Preferably, the amount used can be 1–10 wt%, 10–20 wt%, 20–25 wt%, 25–30 wt%, 30–35 wt%, 32–38 wt%, or 35–40 wt%, and in a specific embodiment, it is 35 wt%.

[0026] According to the above-described chemical mechanical polishing slurry, the abrasive is selected from one or more of inorganic particles, organic particles, and organic-inorganic composite particles.

[0027] According to the aforementioned chemical mechanical polishing slurry, the inorganic particles include one or more of silicon dioxide, metal oxide particles, nitride particles, carbide particles, and diamond particles; the organic particles include one or more of polymethyl methacrylate (PMMA) particles, polyacrylic acid particles, and polyacrylonitrile particles. More preferably, the silicon dioxide is colloidal silicon dioxide.

[0028] According to the above-described chemical mechanical polishing slurry, the metal oxide particles include one or more of cerium oxide, aluminum oxide, and zirconium oxide; the nitride particles include one or two of silicon nitride and boron nitride; and the carbide particles include one or two of silicon carbide and boron carbide.

[0029] According to the aforementioned chemical mechanical polishing slurry, considering the improvement of polishing rate performance, the stability of slurry preservation, and the minimization of wafer surface defects after polishing, the average primary particle size of the abrasive particles is preferably 20–100 nm. The average primary particle size can be 20–45 nm, 45–75 nm, or 75–100 nm; more preferably 30 nm–80 nm, and particularly preferably 40 nm–70 nm. For example, an average primary particle size less than 20 nm will lead to a decrease in the polishing rate performance of the slurry, while a size greater than 100 nm is detrimental to the flatness of the wafer surface after polishing and the stability of the slurry preservation. In a specific embodiment, the primary particle size is 55 nm. The aforementioned limitation of the average primary particle size is beneficial for improving the polishing rate performance of the slurry, the stability of slurry preservation, and reducing wafer surface defects after polishing.

[0030] There is no specific method for determining the average primary particle size of abrasive particles; it can be determined by the BET method. In a particular embodiment, the Flow Sorb II2300 specific surface area analyzer developed by Micromeritics Instrument Corporation was used.

[0031] According to the aforementioned chemical mechanical polishing slurry, considering the improvement of polishing rate performance, the stability of slurry preservation, and the minimization of wafer surface defects after polishing, the average secondary particle size of the abrasive particles is 40–200 nm. Preferably, the average secondary particle size of the abrasive particles can be 40–70 nm, 70–130 nm, or 130–200 nm; more preferably, it is 50 nm–180 nm, and particularly preferably 60 nm–160 nm. For example, an average secondary particle size of less than 40 nm will lead to a decrease in the polishing rate performance of the slurry, while a size greater than 200 nm is detrimental to the flatness of the wafer surface after polishing and the stability of the slurry preservation. In a specific embodiment, it is 110 nm. The above-mentioned limitation of the average secondary particle size of the abrasive particles is beneficial to improving the polishing rate performance of the slurry, the stability of slurry preservation, and reducing wafer surface defects after polishing.

[0032] There is no specific method for determining the average secondary particle size of abrasive particles. It can be determined by dynamic light scattering. In a specific embodiment, the Zetasizer Lab nanoparticle size analyzer developed by Malvern Panalytical was used.

[0033] According to the above-described chemical mechanical polishing slurry, the alkaline compound makes the pH of the chemical mechanical polishing slurry 10-12.

[0034] According to the aforementioned chemical mechanical polishing fluid, the alkaline compound includes one or more of alkali metal hydroxides, carbonates, bicarbonates, and nitrogen-containing organic or inorganic alkaline compounds. Preferably, the alkaline compound is one or more of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, and potassium carbonate.

[0035] According to the above-described chemical mechanical polishing fluid, the water includes one or more of deionized water, pure water, ultrapure water, and distilled water, which serves to dissolve and carry other components of the polishing fluid.

[0036] The second aspect of the present invention provides a method for preparing the chemical mechanical polishing slurry as described above. The method comprises: firstly, mixing an abrasive slurry, an alkaline compound, and water to form a mixture, and adjusting the pH of the mixture to 10-12 using the alkaline compound; then adding a water-soluble small molecule containing a morpholine ring and a water-soluble polymer whose main chain or side chain contains a polyoxyethylene chain, and stirring to mix evenly.

[0037] A third aspect of the present invention provides the application of the chemical mechanical polishing slurry as described above in the polishing of silicon wafers.

[0038] Preferably, the diameter of the silicon wafer is 200-300 mm.

[0039] Preferably, the polishing pressure is 2 to 5 psi.

[0040] Preferably, the rotational speed ratio of the polishing head to the polishing pad is 90-140 rpm: 80-130 rpm.

[0041] Preferably, the flow rate of the polishing fluid is 150–300 mL / min.

[0042] Preferably, the polishing time is 50–70 seconds.

[0043] Preferably, the polishing method includes single-sided polishing or double-sided polishing.

[0044] As described above, this invention provides a chemical mechanical polishing slurry, its preparation method, and its application. The technical solution of this application has the following beneficial effects: The technical solution of this invention can improve the edge collapse phenomenon of silicon wafers while achieving high planarization of the central region of the silicon wafer, thereby improving the overall surface flatness of the silicon wafer. This satisfies the need for silicon wafer planarization in production and ensures the quality and performance of subsequent process steps. Attached Figure Description

[0045] Figure 1 The chemical structural formula of the polyethylene glycol-polyvinyl alcohol graft copolymer Kollicoat IR shown in Examples 1, 2, and 3 of this invention is displayed.

[0046] Figure 2 The chemical structural formulas of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) in Examples 4, 5, and 6 of the present invention are shown.

[0047] Figure 3 The chemical structural formula of hydroxyethyl cellulose shown in Examples 7, 8, and 9 of this invention is displayed.

[0048] Figure 4 The chemical structural formula of 2,2-dimorpholinodiethyl ether is shown in Examples 1, 4, 7 and Comparative Example 2 of the present invention.

[0049] Figure 5 The chemical structural formulas of tri(4-morpholino)phosphine oxides shown are those of Examples 2, 5, 8 and Comparative Example 3 of the present invention.

[0050] Figure 6 The chemical structural formula of 4-(2-methoxyethyl)morpholine is shown in Examples 3, 6, and 9 of this invention. Detailed Implementation

[0051] The following specific examples illustrate the implementation of the present invention to verify its practical feasibility. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0052] It should be noted that the process equipment or apparatus not specifically specified in the following embodiments are all conventional equipment or apparatus in the art. Furthermore, it should be understood that the scope of protection of this invention is not limited to the specific embodiments described below. One or more method steps mentioned in this invention do not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the terminology used in the embodiments of this invention is for describing specific embodiments and not for limiting the scope of protection of this invention. Test methods not specifying specific conditions in the following embodiments are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0053] In the following embodiments of this application, a specific polishing process condition is used, specifically:

[0054] Polishing object: 300mm diameter (100) facet silicon wafer

[0055] Polishing equipment: Tianjin Huahai Qingke Universal-300X

[0056] Polishing pad: SPM-3100 polyurethane polishing pad manufactured by NITTA DuPont, Japan.

[0057] The rotational speed ratio of the polishing head to the polishing pad is 123 rpm: 119 rpm.

[0058] Polishing fluid flow rate: 300 mL / min

[0059] Polishing pressure: 3.0 psi

[0060] Polishing time: 60s.

[0061] Example 1

[0062] This embodiment provides a method for preparing a novel chemical mechanical polishing slurry, comprising the following steps:

[0063] 1) Based on the total mass of the chemical mechanical polishing slurry, mix 35% by mass of colloidal silica (average primary particle size of 55nm, average secondary particle size of 110nm), 1.6% by mass of tetramethylammonium hydroxide (TMAH), 1% by mass of potassium carbonate and 61.7% by mass of deionized water evenly.

[0064] 2) Add 0.3% by mass of 2,2-dimorpholinodiethyl ether and 0.4% by mass of KollicoatIR, adjust the pH to 11.5 with the help of tetramethylammonium hydroxide (TMAH) and potassium carbonate, stir and mix evenly at room temperature (25°C) for 30 minutes to finally obtain the chemical mechanical polishing slurry.

[0065] The chemical mechanical polishing slurry obtained by the above process is diluted with ion-exchange water at a mass ratio of 30 times to obtain the polishing slurry for use.

[0066] Example 2

[0067] This embodiment provides a method for preparing a novel chemical mechanical polishing slurry, comprising the following steps:

[0068] The 2,2-dimorpholinodiethyl ether in Example 1 was replaced with tri(4-morpholino)phosphine oxide, and the rest remained exactly the same as in Example 1.

[0069] Example 3

[0070] This embodiment provides a method for preparing a novel chemical mechanical polishing slurry, comprising the following steps:

[0071] The 2,2-dimorpholinodiethyl ether in Example 1 was replaced with 4-(2-methoxyethyl)morpholine, and the rest remained exactly the same as in Example 1.

[0072] Example 4

[0073] This embodiment provides a method for preparing a novel chemical mechanical polishing slurry, comprising the following steps:

[0074] Polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol (number average molecular weight 8400) was used. The molar ratio of Kollicoat IR in Example 1 is 4:1, while the rest remains exactly the same as in Example 1.

[0075] Example 5

[0076] This embodiment provides a method for preparing a novel chemical mechanical polishing slurry, comprising the following steps:

[0077] Polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol (number average molecular weight 8400) was used. The molar ratio of Kollicoat IR in Example 2 is 4:1, while the rest remains exactly the same as in Example 2.

[0078] Example 6

[0079] This embodiment provides a method for preparing a novel chemical mechanical polishing slurry, comprising the following steps:

[0080] Polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol (number average molecular weight 8400) was used. The molar ratio of Kollicoat IR in Example 3 is 4:1, while the rest remains exactly the same as in Example 3.

[0081] Example 7

[0082] This embodiment provides a method for preparing a novel chemical mechanical polishing slurry, comprising the following steps:

[0083] The Kollicoat IR in Example 1 was replaced with hydroxyethyl cellulose (HEC) (weight average molecular weight 1.2 million), and the rest remained exactly the same as in Example 1.

[0084] Example 8

[0085] This embodiment provides a method for preparing a novel chemical mechanical polishing slurry, comprising the following steps:

[0086] The Kollicoat IR in Example 2 was replaced with hydroxyethyl cellulose (HEC) (weight average molecular weight 1.2 million), and the rest remained exactly the same as in Example 2.

[0087] Example 9

[0088] This embodiment provides a method for preparing a novel chemical mechanical polishing slurry, comprising the following steps:

[0089] The Kollicoat IR in Example 3 was replaced with hydroxyethyl cellulose (HEC) (weight average molecular weight 1.2 million), and the rest remained exactly the same as in Example 3.

[0090] Comparative Example 1

[0091] The difference between this comparative example and Example 1 is that no water-soluble small molecules containing morpholine rings and water-soluble polymers containing polyoxyethylene chains in the main chain or side chain were used, i.e., no 2,2-dimorpholinodiethyl ether and Kollicoat IR were used; the rest is completely the same as in Example 1.

[0092] Comparative Example 2

[0093] The difference between this comparative example and Example 1 is that: no water-soluble polymer containing polyoxyethylene chains in the main chain or side chain was used, i.e., Kollicoat IR was not used; the rest is exactly the same as in Example 1.

[0094] Comparative Example 3

[0095] The difference between this comparative example and Example 2 is that a water-soluble polymer containing polyoxyethylene chains in the main chain or side chains was not used, i.e., Kollicoat IR was not used. The rest is completely identical to Example 2.

[0096] The performance of CMP (Chemical Mechanical Polishing) slurries is generally evaluated by measuring the polishing rate and the edge flatness of the silicon wafer after polishing. The polishing rate and silicon wafer edge flatness are measured using a bare wafer geometrology system (WaferSight2+, KLA Tencor, Milpitas, CA, USA).

[0097] The chemical mechanical polishing slurries obtained in Examples 1-6 and Comparative Examples 1-3 were used to test the edge flatness of silicon wafers. Specifically, ESFQR was used as the evaluation index for silicon wafer surface flatness. ESFQR (Edge flatnessmetric, Sector-based, Front surface referenced, least squares fit reference plane, Range of the data within sector) refers to dividing a sector 1 mm from the edge of the silicon wafer into multiple points and measuring the difference between the highest and lowest points of the silicon wafer surface morphology relative to the least squares reference plane within each point. ΔESFQR represents the improvement in silicon wafer surface flatness before and after polishing. In this embodiment, a negative ΔESFQR is used to represent the improvement in silicon wafer surface flatness by the CMP polishing slurry.

[0098] The results of silicon wafer edge flatness testing are shown in Table 1. The ΔESFQR ratios for each example in Table 1 are ratios equal to 100% of the ΔESFQR value when polished with the CMP polishing slurry in Comparative Example 1. A higher ratio indicates better improvement in silicon wafer edge flatness. The ΔESFQR value in Comparative Example 1 when polished with the CMP polishing slurry is -6.5 nm.

[0099] The chemical mechanical polishing slurries obtained in Examples 1-6 and Comparative Examples 1-3 were used to test the flatness of the silicon wafer center. Specifically, SFQR (Site-Front Surface Referenced Least Squares / Range) was used as the evaluation index for the flatness of the silicon wafer center region. SFQR refers to dividing a circular region formed 2mm from the edge of the silicon wafer into multiple units (e.g., dividing it into multiple 26mm × 8mm unit regions) and measuring the difference between the highest and lowest points of the silicon wafer surface morphology within each unit region relative to the least squares reference plane. ΔSFQR represents the improvement in the flatness of the silicon wafer center region before and after polishing. In this embodiment, a negative ΔSFQR is used to represent the improvement in the flatness of the silicon wafer center region by the polishing slurry.

[0100] The flatness test results of the central region of the silicon wafer are shown in Table 1. The ΔSFQR ratio of each example is the ratio of the ΔSFQR value when polished with CMP polishing slurry in Comparative Example 1 to 100%. The larger the ratio value, the better the flatness improvement of the central region of the silicon wafer. The ΔSFQR of CMP polishing slurry in Comparative Example 1 is -4.3nm.

[0101] Table 1

[0102]

[0103]

[0104] Note: In Comparative Example 1, the ΔESFQR value during polishing with CMP polishing slurry was -6.5nm; the ΔSFQR was -4.3nm.

[0105] As shown in Table 1, the chemical mechanical polishing slurry prepared using the method of this application can significantly reduce the ΔSFQR value while maintaining a low ΔESFQR value. This indicates that the chemical mechanical polishing slurry provided by this application, which contains water-soluble small molecules with morpholine rings and polymers with polyoxyethylene chains in the main chain or side chain, can improve the flatness of the silicon wafer edge and the flatness of the silicon wafer center, compared with the chemical mechanical polishing slurry without these two types of substances (Comparative Example 1), thus improving the overall surface flatness of the silicon wafer. Compared with the chemical mechanical polishing slurry containing only water-soluble small molecules with morpholine rings (Comparative Examples 2 and 3), the water-soluble small molecules with morpholine rings and polymers with polyoxyethylene chains in the main chain or side chain work together to significantly improve the flatness of the silicon wafer center while maintaining a certain improvement in the flatness of the silicon wafer edge. The above results indicate that the technical solution of the present invention, namely the chemical mechanical polishing slurry containing water-soluble small molecules with morpholine rings and polymers with polyoxyethylene chains in the main chain or side chain, can improve the edge collapse phenomenon of silicon wafers while achieving high flatness in the central region of silicon wafers, thereby improving the overall surface flatness of silicon wafers.

[0106] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A chemical mechanical polishing liquid, characterized by comprising: The raw material components include: a water-soluble small molecule containing a morpholine ring, a water-soluble polymer, an abrasive, an alkaline compound, and water; The water-soluble small molecule containing a morpholine ring includes one or more of 2,2-dimorpholinyl diethyl ether, tris(4-morpholinyl)phosphine oxide, and 4-(2-methoxyethyl)morpholine; The water-soluble polymer includes one or more of polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol, polyethylene glycol-polyvinyl alcohol graft copolymer, and hydroxyethyl cellulose; The average primary particle size of the abrasive is 20 nm to 100 nm; The average secondary particle size of the abrasive is 40 nm to 200 nm; The alkaline compound causes the pH of the chemical mechanical polishing liquid to be 10 to 12; The abrasive is silicon dioxide; The amount of the water-soluble small molecule containing a morpholine ring is 0.005 to 0.5 wt% based on the total mass of the chemical mechanical polishing liquid; the amount of the water-soluble polymer is 0.005 to 0.5 wt%; and the amount of the abrasive is 1 to 40 wt%.

2. The chemical mechanical polishing liquid according to claim 1, wherein The number average molecular weight of the polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol is 2000 to 100000, in a molar ratio of 2 to 10:

1. And / or, the weight average molecular weight of the hydroxyethyl cellulose is 100,000 to 1,300,000; And / or, the number average molecular weight of the polyethylene glycol-polyvinyl alcohol graft copolymer is 10,000 to 500,000, and the polyvinyl alcohol grafting rate is 20% to 300%.

3. The chemical mechanical polishing liquid according to claim 1, wherein The alkaline compound includes one or more of an alkali metal hydroxide, a carbonate, a bicarbonate, a nitrogen-containing organic alkaline compound, and a nitrogen-containing inorganic alkaline compound.

4. A method for preparing the chemical mechanical polishing liquid according to any one of claims 1 to 3, characterized by, First, the abrasive slurry, the alkaline compound, and water are mixed to form a mixed liquid, and the pH of the mixed liquid is adjusted to 10 to 12 with the aid of the alkaline compound, and then the water-soluble small molecule containing a morpholine ring and the water-soluble polymer are added and stirred to mix uniformly.

5. Use of the chemical mechanical polishing liquid according to any one of claims 1 to 3 in polishing of a silicon wafer.

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