Phosphonic acid ligand modified cerium oxide polishing solution and preparation method thereof

Abstract

The invention provides a phosphonic acid ligand modified cerium oxide polishing solution and a preparation method thereof. The polishing solution is mainly prepared by mixing water and phosphonic acid ligand modified cerium oxide according to a mass ratio of (94: 5)-(92: 7). According to the polishing solution, through modification of the phosphoric acid ligand, the chemical and physical properties of the cerium oxide abrasive are optimized, and the reactivity and the removal rate in the chemical mechanical polishing process can be improved, so that the polishing efficiency is effectively improved; a stable surface modification layer is formed through interaction with the surfaces of cerium oxide particles, so that the aggregation tendency among the particles is reduced, the grinding material can be more uniformly dispersed in a solution, and the uniformity of suspension liquid is improved; hydrophilic groups are arranged on the surface, so that the solubility of the particles in a solution is improved, and the settling velocity of the particles is reduced, thereby prolonging the stabilization time of a suspension.

Description

Technical Field

[0001] The invention belongs to the technical field of rare earth materials, in particular to a phosphonic acid ligand-modified cerium oxide polishing liquid and a preparation method thereof. Background Art

[0002] The rapid development of information and optoelectronics has promoted the continuous updating of chemical mechanical polishing (CMP) technology. In addition to equipment and materials, the acquisition of ultra-high precision surfaces depends more on the design and industrial production of efficient abrasive particles, as well as the preparation of corresponding polishing slurries. Moreover, with the continuous improvement of surface processing accuracy and efficiency requirements, the requirements for efficient polishing materials are also getting higher and higher. Cerium oxide has been widely used in the precision processing of microelectronic devices and precision optical components.

[0003] The reason why cerium oxide can play an excellent role in the polishing process is mainly due to its excellent chemical reactivity and mechanical grinding ability. During the polishing operation, cerium oxide particles can react chemically with the surface of the silicon wafer to form an oxide film, which is then removed by mechanical friction to achieve surface flattening. In addition, the structural characteristics of cerium oxide particles enable it to polish at a higher rate while maintaining a low defect rate, thereby ensuring flatness while also improving the overall efficiency of polishing.

[0004] However, traditional cerium oxide polishing materials still face some challenges in practical applications, such as the difficulty in balancing the polishing rate and surface defects, as well as the problem of particle agglomeration during the polishing process, which may affect the uniformity of polishing. Therefore, how to optimize the preparation process of cerium oxide particles, perform surface modification or adopt more effective dispersion technology to improve its suspension stability has become the focus of current research.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first purpose of the present invention is to provide a phosphonic acid ligand-modified cerium oxide polishing liquid, which uses a phosphonic acid ligand to modify cerium dioxide, thereby improving the dispersion characteristics and chemical stability of the polishing liquid, thereby optimizing the polishing performance during chemical mechanical polishing (CMP), and exhibiting excellent dispersibility and suspension stability in the absence of any additives.

[0007] The second purpose of the present invention is to provide a method for preparing the above-mentioned phosphonic acid ligand-modified cerium oxide polishing liquid. The preparation method is simple and can ensure the consistency of the particle size of the modified cerium oxide abrasive; reduce costs and be easier to promote on a large scale.

[0008] The third object of the present invention is to provide the application of the phosphonic acid ligand-modified cerium oxide polishing liquid and the polishing liquid prepared by the preparation method in chemical mechanical polishing of silicon dioxide.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: The invention provides a phosphonic acid ligand-modified cerium oxide polishing liquid, which is mainly prepared by mixing water and cerium oxide modified by the phosphonic acid ligand in a mass ratio of (94:5) to (92:7).

[0010] In the present invention, the main function of water is to dissolve and disperse the cerium oxide abrasive modified by the phosphonic acid ligand, so that the mass of the modified cerium oxide abrasive accounts for 5%-7.1% of the entire dispersion system, so as to achieve a better dispersion effect. The particle size of the cerium oxide abrasive modified by the phosphonic acid ligand is relatively large, and intermolecular forces will be generated between each other, so the size of the intermolecular forces needs to be considered during the dispersion in water; when the content of the modified cerium oxide abrasive is too high, the intermolecular forces will be large, and it is easier to agglomerate when dispersed in water, resulting in poor suspension stability and inability to stably suspend for a long time; and when the content of the modified cerium oxide abrasive is low, the removal rate of the polishing liquid prepared will be poor, and a good polishing effect cannot be achieved.

[0011] Preferably, as a further specific embodiment, it is mainly prepared by mixing water: cerium oxide modified with phosphonic acid ligands in a mass ratio of 95:5 or 94:5.

[0012] In the actual preparation process, after the modified cerium oxide is dispersed in water, when the proportion in the dispersion system is close to 5%, the dispersion system is more stable. Under this concentration of the dispersion system, the molecular force between each modified cerium oxide particle is more moderate, which can ensure the polishing performance of the polishing liquid, and make the modified cerium oxide particles suspended in water for a long time and stably, reducing the possibility of agglomeration or agglomeration and increasing its suspension stability.

[0013] Preferably, as a further specific implementation, the molar ratio of the phosphorus element in the cerium oxide modified with the phosphonic acid ligand to the cerium element in the cerium oxide modified with the phosphonic acid ligand is (1:2)-(1:10).

[0014] In the process of modifying cerium oxide, cerium oxide will form hydroxyl groups in water and adsorb with phosphonic acid / phosphoric acid groups, which will increase steric hindrance and produce charge effect, so that cerium oxide particles are mutually dispersed in water, thereby achieving the purpose of improving suspension stability. Since the phosphonic acid / phosphoric acid group itself is a relatively large group, steric hindrance needs to be considered in the modification process; if the ratio of phosphonic acid ligands is designed to be high, the excess phosphonic acid ligands will not only be difficult to combine with cerium oxide abrasives, resulting in waste, but also easily produce some uncontrollable side reactions that affect cerium oxide abrasives and reduce the performance of modified cerium oxide abrasives; if the ratio of phosphonic acid ligands is designed to be low, the phosphonic acid / phosphonic acid groups cannot be evenly grafted on the surface of cerium oxide to form a uniform and stable modified cerium oxide abrasive, thereby reducing its suspension stability.

[0015] Preferably, as a further specific implementation, the molar ratio of the phosphorus element in the cerium oxide modified with the phosphonic acid ligand to the cerium element in the cerium oxide modified with the phosphonic acid ligand is 1:5.

[0016] Under this molar ratio, the phosphonic acid / phosphoric acid groups can be uniformly and stably adsorbed on the surface of cerium oxide, forming a reasonable steric hindrance while generating a charge effect, which can better disperse the cerium oxide, thereby improving its suspension stability.

[0017] Preferably, as a further specific embodiment, the phosphonic acid ligand is any one or more of diethylenetriaminepenta(methylenephosphonic acid), aminotrimethylenephosphonic acid, (3-amino-1-hydroxypropane-1,1-diyl)diphosphonic acid, (1-hydroxy-2-(1H-imidazol-1-yl)ethane-1,1-diyl)diphosphonic acid, 1,6-hexanediphosphonic acid or phosphoric acid; Preferably, the phosphonic acid ligand is diethylenetriaminepenta(methylenephosphonic acid).

[0018] In the present invention, an organic acid or inorganic acid containing more phosphonic acid / phosphoric acid groups is selected to modify cerium oxide. On the one hand, the organic acid or inorganic acid with more phosphonic acid / phosphoric acid groups can modify cerium oxide under relatively low conditions; on the other hand, the above-selected phosphonic acid ligand has a higher success rate of grafting with cerium oxide and is easier to be evenly distributed on the surface of cerium oxide.

[0019] Through experimental exploration, it was found that diethylenetriaminepenta(methylenephosphonic acid) had the best modification effect on cerium oxide. It is speculated that this may be because diethylenetriaminepenta(methylenephosphonic acid) contains more phosphonic acid groups and has good synergistic ability, which can better produce adsorption with the hydroxyl groups in cerium oxide, thereby further increasing the steric hindrance while increasing the charge effect, and better modifying cerium oxide.

[0020] The present invention also provides a method for preparing the phosphonic acid ligand-modified cerium oxide polishing liquid, comprising: preparing cerium oxide; The cerium oxide and the phosphonic acid ligand are mixed, and heated while stirring to obtain a modified cerium oxide solution; Centrifuging, drying and grinding the modified cerium oxide solution to obtain modified cerium oxide powder; The prepared modified cerium oxide powder is prepared into an aqueous solution to obtain the product.

[0021] The preparation method simplifies the preparation process, making the preparation process simpler, and can ensure the consistency of the particle size of the modified cerium oxide abrasive; it reduces costs and is easier to promote on a large scale.

[0022] Preferably, as a further specific embodiment, the centrifugal rotation speed is ≥11000r / min.

[0023] In the present invention, the prepared modified cerium oxide needs to be centrifuged, and the centrifugal speed cannot be lower than 11000r / min. When the centrifugal speed is lower than this value, it will lead to incomplete centrifugation, and further make the modified cerium oxide powder difficult to disperse in the step of preparing the aqueous solution.

[0024] Preferably, as a further specific implementation manner, the stirring rotation speed is 800r / min-1000r / min.

[0025] In the process of mixing cerium oxide and phosphonic acid ligands, it is necessary to stir and heat them at the same time, and the stirring rate is limited. Since the phosphonic acid ligands themselves are relatively stable and not easy to react, they need to be stirred continuously during the heating process to increase the particle movement, thereby increasing the mixing rate of the phosphonic acid ligands and the cerium dioxide molecules, thereby increasing the reaction rate.

[0026] In this process, the stirring rate needs to be moderate, not too fast or too slow. In the present invention, if the stirring rate is too fast, eddy currents and particle collisions will be generated, which will reduce the quality of the product; and if the stirring rate is too slow, the rate of combination will also be reduced, affecting the quality of the product.

[0027] Preferably, as a further specific embodiment, the heating temperature is 30°C-110°C; Preferably, the heating temperature is 100°C.

[0028] The reaction temperature of the phosphonic acid ligand is relatively high. However, the modification method of the present invention can achieve the modification of cerium oxide by the phosphonic acid ligand at a relatively low temperature, while ensuring the grafting efficiency of the phosphonic acid ligand on cerium oxide.

[0029] Compared with the prior art, the present invention has the following beneficial effects: Through the modification of phosphate ligands, the chemical and physical properties of cerium oxide abrasives are optimized, which can improve the reactivity and removal rate in the chemical mechanical polishing process, thereby effectively improving the polishing efficiency; by interacting with the surface of cerium oxide particles, a stable surface modification layer is formed, which reduces the aggregation tendency between particles, enables the abrasive to be more evenly dispersed in the solution, and improves the uniformity of the suspension; the surface has hydrophilic groups, which increases the solubility of the particles in the solution and reduces the particle sedimentation rate, thereby extending the stability time of the suspension.

[0030] The modified cerium oxide nano-abrasive prepared by the preparation method of the present invention can maintain its suspension (D50) for 1-2 months without any additives. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 : X-ray diffraction image of cerium oxide abrasive modified with phosphate ligand; Figure 2 :Thermogravimetric analysis images of cerium oxide abrasive modified with phosphate ligands; Figure 3 : Transmission electron microscopy image of cerium oxide abrasive modified with phosphate ligands; Figure 4 : Comparison of suspension stability of modified cerium oxide D50 prepared at 30℃-100℃. DETAILED DESCRIPTION

[0032] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0033] Example 1 1. Preparation of Cerium Oxide 200 g of cerium carbonate was transferred to a muffle furnace and heated to 600° C. at a rate of 20° C. per minute at room temperature for 12 hours. After natural cooling, the sample was ground with a grinder and then dried to obtain a yellow powder sample, i.e., a CeO2 sample.

[0034] 2. Preparation of phosphonic acid ligand-modified cerium oxide abrasive Take 5g of CeO2 sample and mix with 1mL of 50% diethylenetriamine penta (methylenephosphonic acid) solution (TDPMP solution, density 1.35g / ml) and heat, at this time the molar ratio of phosphorus to cerium is 1:5. Then heat to 100℃ in an oil bath and stir at 800r / min for 12 hours.

[0035] The solid obtained after heating was centrifuged at a centrifugal speed of 11000r / min, and the solid powder was dried after centrifugation. It was vacuum dried at 80°C overnight to ensure complete drying. After drying, the powder was ground into a white powder of DTPMP@CeO2.

[0036] 3. Preparation of cerium oxide polishing liquid modified with phosphonic acid ligand Accurately weigh 2.5 g (accurate to 0.0001 g) of the cerium oxide sample modified with phosphonic acid, place it in a 150 mL beaker, add a little water to make a pulp, add 30-40 mL of water, transfer it to a 50 mL graduated flask, add water to dilute to the scale, at which point the mass ratio of water to the modified cerium oxide is 95:5. Then transfer the diluted mixture into a beaker, place it on an electric magnetic stirrer, stir it at room temperature for 10 minutes, then transfer it into a cylindrical separatory funnel, and leave it at room temperature for 4 hours to obtain the mixture. Figure 1-Figure 3 It can be seen from the X-ray diffraction image, thermogravimetric analysis image and transmission electron microscopy image of the cerium oxide abrasive modified by the phosphonic acid ligand.

[0037] The density of water is 1g / cm³, the mass of water = the volume of water × the density of water.

[0038] 4. Suspension test Take 0.5 g-1.0 g of powder sample and place it in a 50 mL beaker filled with 10 mL of deionized water. Ultrasonic disperse it in a water bath ultrasonic tank (add an appropriate amount of water to the ultrasonic tank in advance, and the amount of water should just cover the sample solution in the beaker) for 20 min and measure immediately.

[0039] After standing for 4 hours, use a pipette to draw 5 mL of the suspension from about 6 mL below the liquid level on the top of the cylindrical separatory funnel, transfer it into a 200 mL volumetric flask and dilute it to the mark with water. Then open the piston all at once and put about 10 mL of the lower suspension into a 50-liter beaker, use a pipette to draw 5 mL of it into a 200 mL volumetric flask, and dilute it to the mark with water. Shake the above two samples, use a pipette to draw the required milliliters each and transfer them to a 50 mL volumetric flask, and dilute it to the mark with an acetone-water mixture. It is sufficient to know that the measured value is 50% of the initial value, and record the time at this time.

[0040] Example 2 The specific implementation method is consistent with Example 1, only the type of phosphonic acid ligand is changed, as follows: When no phosphate ligand was used, a CeO2 sample was obtained; When diethylenetriamine penta(methylenephosphonic acid) was used, Example 1 was obtained; When (3-amino-1-hydroxypropane-1,1-diyl)diphosphonic acid was used, sample No. 1 was obtained; When 2,3-ethylene oxide dicarboxylic acid was used, sample No. 2 was obtained; When (1-hydroxy-2-(1H-imidazol-1-yl)ethane-1,1-diyl)diphosphonic acid was used, sample No. 3 was obtained; When 1,6-hexanediphosphonic acid was used, sample No. 4 was obtained; When phosphoric acid was used, sample No. 5 was obtained; The D50 value was determined according to the suspension test in Example 1. The experimental results are shown in Table 2.

[0041] Table 1: Effect of different phosphate ligands on the suspension properties of cerium oxide nanoabrasives.

[0042]

[0043] It can be seen from the data in Example 2 that diethylenetriamine penta(methylenephosphonic acid) has a significant improvement in the suspension stability of cerium oxide abrasive, with D50 reaching 452h, followed by 1,6-hexanediphosphonic acid, with D50 reaching 356h; inorganic phosphoric acid and (1-hydroxy-2-(1H-imidazole-1-yl)ethane-1,1-diyl)diphosphonic acid have poor improvement in suspension stability, but compared with CeO2 without any modification, they can also improve the suspension stability of cerium oxide abrasive.

[0044] By consulting the information and analyzing the experimental data, the reason may be that diethylenetriaminepenta(methylenephosphonic acid) itself has more phosphonic acid groups and stronger stability. During the heating process, the phosphonic acid groups it contains can be better adsorbed on the surface of cerium oxide, thereby increasing the steric hindrance of cerium oxide, achieving effective modification of cerium oxide, and further improving its suspension stability.

[0045] Although other organic phosphonic acids or inorganic phosphoric acids can modify cerium oxide, the modification effect is general. It is speculated that the reason may be that the phosphonic acid / phosphoric acid groups generated during the heating process have limited effect on increasing the steric hindrance of cerium oxide, and the charge effect is weak, which further limits the increase in its suspension stability.

[0046] Example 3 The specific steps of preparing cerium oxide, preparing phosphonic acid ligand-modified cerium oxide abrasive and suspension stability test are consistent with those in Example 1, and the mass ratio of water to phosphonic acid ligand-modified cerium oxide is changed. The specific changes are shown in Table 2.

[0047] Table 2: Effect of the mass ratio of water to cerium oxide on suspension stability

[0048] The present invention limits the mass of water and cerium oxide modified with phosphonic acid ligands. Experimental data show that when the mass ratio between the two is within the range of (94:5)-(92:7), D50 is greater than 400h, which has good dispersibility.

[0049] When the mass ratio of water to modified cerium oxide is within the range of (94:5) - (92:7), the modified cerium oxide can be fully dispersed in water, so that the intermolecular force between the modified cerium oxide particles is within a more reasonable range, and the particles will not agglomerate or fail to achieve the polishing effect due to too little content.

[0050] Example 4 The specific steps of preparing cerium oxide, preparing cerium oxide polishing liquid modified with phosphonic acid ligands, and testing the suspension stability are consistent with those in Example 1, except that the molar ratio of phosphorus to cerium in the step of preparing cerium oxide abrasive modified with phosphonic acid ligands is changed. The specific changes are shown in Table 3.

[0051] Table 3: Effect of changes in the molar amounts of phosphorus and cerium on suspension stability

[0052] The mass ratio of phosphorus to cerium was further adjusted by adjusting the concentration of diethylenetriamine penta(methylenephosphonic acid) solution. It can be seen from the experimental results that when the molar ratio of phosphorus to cerium is in the range of (1:2)-(1:10), the suspension of cerium oxide is significantly improved; when it exceeds this range, the improvement of suspension is not obvious. The reason is that phosphorus and cerium cannot be combined in a 1:1 ratio. In the actual experiment, the mass of cerium oxide used is actually greater than the mass of phosphonic acid ligands. Therefore, the molar amount of cerium oxide in the actual reaction is greater than the molar amount of phosphorus. Too much phosphorus can easily cause large steric hindrance, so that phosphonic acid / phosphonic acid groups cannot be evenly grafted on the surface of cerium oxide; when the phosphorus content is low, it cannot fully adsorb on the surface of cerium oxide, thereby reducing its suspension stability.

[0053] Preferably, at a molar ratio of 1:5, the phosphonic acid / phosphoric acid groups can be adsorbed on the cerium oxide to the greatest extent possible to form a relatively stable modified structure, thereby ensuring the suspension stability.

[0054] Example 5 The specific implementation steps are consistent with those in Example 1, except that the oil bath stirring and heating time during the modification process is changed.

[0055] The prepared cerium oxide nanoabrasive was prepared into a 1% cerium oxide abrasive suspension, and its D50 value was measured according to the suspension property measurement experiment in Example 1. The experimental results are shown in Table 4.

[0056] Table 4: Effect of different heating temperatures and heating times on the suspension of cerium oxide nanoabrasives

[0057] pass Figure 4 The data of Example 5 can also reflect that different heating times have an important influence on the suspension stability of the cerium oxide nanoabrasive suspension. Figure 4 From left to right, the suspension stability of the polishing liquid prepared at 30℃-100℃. At a lower temperature (such as 30℃), the reaction rate is slower, the modification effect of the phosphonic acid ligand on the surface of cerium dioxide is not sufficient, and the suspension stability is poor. Figure 4 It can be seen that at 30°C, cerium oxide is difficult to be stably suspended to form a suspension, and the suspension time is short, which is 56 hours. After 56 hours, it sinks to the bottom of the bottle to form a precipitate. As the temperature rises, the reaction speed is accelerated, the reaction is more complete, and the suspension stability increases. 100°C is the optimal reaction temperature, which allows the phosphonic acid ligand to form a stable modification layer on the surface of cerium dioxide. At 100°C, cerium oxide can be stably suspended for 452 hours, achieving the best effect.

[0058] Comparative Example 1 The specific steps of preparing cerium oxide, preparing phosphonic acid ligand-modified cerium oxide abrasive and suspension stability test are consistent with Example 3, and the mass ratio of water to phosphonic acid ligand-modified cerium oxide is changed. The specific changes are shown in Table 5.

[0059] Table 5: Effect of the mass ratio of water to cerium oxide on suspension stability

[0060] Comparing Comparative Example 1 with Example 3, it can be seen that when there is too much or too little water, D50 will be significantly reduced, resulting in unsatisfactory suspension stability. When there is too much water, the intermolecular force between the modified cerium oxide particles will be reduced, making the intermolecular force between the cerium oxide particles weaker, thereby reducing the suspension stability and having a greater impact on the polishing rate; when there is too little water, the intermolecular force is larger, and it is easy for the modified cerium oxide particles to interact with each other and agglomerate, which is not conducive to the long-term storage of the polishing liquid.

[0061] Experimental Example 1 The polishing rate of the sample in Example 3 was tested. Then 2.5 g of the modified CeO2 abrasive was uniformly dispersed in 500 mL of deionized water, and after 30 minutes of ultrasonic treatment, a polishing liquid was prepared to polish a 1 mm thick silicon wafer. For the abrasive samples modified with different phosphate ligands, the specific polishing rates are shown in Table 6.

[0062] Table 6: Effect of different phosphate ligand modifications on the polishing rate of cerium oxide nanoabrasives.

[0063]

[0064] Different phosphate ligand molecular structures will affect the chemical properties of CeO2 particle surfaces, thereby changing the interaction between particles and silicon wafers. Phosphoric acid ligands may reduce active sites or reduce the interaction between particles and materials, resulting in a reduction in polishing rate. The phosphonic acid / phosphoric acid ligands selected by the present invention can significantly improve the polishing rate of cerium oxide abrasives, and can also effectively improve suspension stability, with significant technological progress.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phosphonic acid ligand-modified cerium oxide polishing liquid, characterized in that: The method is mainly prepared by mixing water and cerium oxide modified with phosphonic acid ligands in a mass ratio of (94:5) to (92:7).

2. The phosphonic acid ligand-modified cerium oxide polishing liquid according to claim 1, characterized in that: The water and the cerium oxide modified with the phosphonic acid ligand are mixed in a mass ratio of 95:5 or 94:

5.

3. The phosphonic acid ligand-modified cerium oxide polishing liquid according to claim 1, characterized in that: The molar ratio of the phosphorus element in the cerium oxide modified with the phosphonic acid ligand to the cerium element in the cerium oxide modified with the phosphonic acid ligand is (1:2)-(1:10).

4. The phosphonic acid ligand-modified cerium oxide polishing liquid according to claim 3, characterized in that: The molar ratio of the phosphorus element in the cerium oxide modified with the phosphonic acid ligand to the cerium element in the cerium oxide modified with the phosphonic acid ligand is 1:

5.

5. The phosphonic acid ligand-modified cerium oxide polishing liquid according to claim 1, characterized in that: The phosphonic acid ligand is any one or more of diethylenetriaminepenta(methylenephosphonic acid), aminotrimethylenephosphonic acid, (3-amino-1-hydroxypropane-1,1-diyl)diphosphonic acid, (1-hydroxy-2-(1H-imidazol-1-yl)ethane-1,1-diyl)diphosphonic acid, 1,6-hexanediphosphonic acid or phosphoric acid; Preferably, the phosphonic acid ligand is diethylenetriaminepenta(methylenephosphonic acid).

6. A method for preparing a phosphonic acid ligand-modified cerium oxide polishing liquid as claimed in any one of claims 1 to 5, characterized in that: The steps include: preparing cerium oxide; The cerium oxide and the phosphonic acid ligand are mixed, and heated while stirring to obtain a modified cerium oxide solution; Centrifuging, drying and grinding the modified cerium oxide solution to obtain modified cerium oxide powder; The prepared modified cerium oxide powder is prepared into an aqueous solution to obtain the product.

7. The method for preparing the phosphonic acid ligand-modified cerium oxide polishing liquid according to claim 6, characterized in that: The centrifugal rotation speed is ≥11000r / min.

8. The method for preparing the phosphonic acid ligand-modified cerium oxide polishing liquid according to claim 6, characterized in that: The stirring speed is 800r / min-1000r / min.

9. The method for preparing the phosphonic acid ligand-modified cerium oxide polishing liquid according to claim 6, characterized in that: The heating temperature is 30°C-110°C; Preferably, the heating temperature is 100°C.

10. Use of the phosphonic acid ligand-modified cerium oxide polishing liquid as described in any one of claims 1 to 5 and the phosphonic acid ligand-modified cerium oxide polishing liquid prepared by the preparation method of the phosphonic acid ligand-modified cerium oxide polishing liquid as described in claims 7 to 9 in chemical mechanical polishing of silicon dioxide.

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