A polishing liquid with photocatalytic assistance and its preparation method

Abstract

The present invention discloses a polishing liquid with a photocatalytic auxiliary effect and a preparation method thereof; it relates to the technical field of polishing liquids and is made of the following components: coated cerium dioxide composite, diamond micropowder, surfactant, lubricant, chelating agent, sodium stearate, dispersant, organosilicon defoamer, deionized water; the polishing liquid with a photocatalytic auxiliary effect prepared by the present invention has high suspension stability, high polishing efficiency, fast heat dissipation, and can be applied to the polishing processing of various materials such as cemented carbide, ceramics, optical glass, gemstones, integrated circuits, etc.; the present invention uses ultraviolet light for photocatalysis to assist in increasing the kinetic energy of the particles in the polishing liquid, and through the close combination of mechanical action and chemical action, it significantly makes up for the occurrence of large protrusions generated by mechanical action, resulting in an increase in roughness, effectively reduces various defects generated by mechanical action, and greatly improves the surface polishing quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of polishing fluids, and particularly relates to a polishing fluid with photocatalytic auxiliary efficacy and a preparation method thereof. Background Art

[0002] Diamond is a face-centered cubic crystal structure formed by the covalent bonding of four adjacent carbon atoms. The covalent bond length is 0.15 nm, the included angle is 109°28′, and the lattice constant is

[0003] Due to its unique structure, diamond has a very high hardness and also has various properties such as low friction, high thermal conductivity, electrical insulation, and extremely strong chemical inertness.

[0004] Diamond is the hardest substance known in nature to humans. Due to these excellent properties, diamond is widely used in many fields such as mechanical tool processing, gemstone processing, electronic and electrical manufacturing, and drilling and mining. In addition, it has unique application characteristics in many aspects such as electricity, optics, acoustics, and mechanics.

[0005] In chemical mechanical polishing (CMP) technology, the polishing fluid is directly related to the polishing effect. The performance of the polishing fluid will directly affect the surface quality of the workpiece after polishing. By introducing diamond into the polishing fluid, the polishing effect of the polishing fluid can be improved. Usually, diamond powder is introduced into the polishing fluid, and its cost is relatively high. If the amount of diamond powder is too small, the polishing efficiency of the polishing fluid will be reduced, and the polishing quality will also be reduced.

[0006] Therefore, it is necessary to further improve the existing technology. Summary of the Invention

[0007] The purpose of the present invention is to provide a polishing fluid with photocatalytic auxiliary efficacy and a preparation method thereof to solve the deficiencies in the existing technology.

[0008] The technical scheme adopted by the present invention is as follows:

[0009] A polishing fluid with photocatalytic auxiliary efficacy is made of the following components by weight: 12 - 18 parts of coated cerium dioxide composite, 6 - 9 parts of diamond micropowder, 1.0 - 1.5 parts of surfactant, 0.2 - 0.3 parts of lubricant, 0.1 - 0.4 parts of chelating agent, 1.2 - 1.8 parts of sodium stearate, 3 - 4 parts of dispersant, 0.3 - 0.6 parts of organosilicon defoamer, and 80 - 90 parts of deionized water.

[0010] As a further technical scheme: The preparation method of the coated cerium dioxide composite is:

[0011] (1) First, prepare a cetyltrimethylammonium bromide solution, and then add the cetyltrimethylammonium bromide solution to the reaction kettle;

[0012] (2) Weigh cerium dioxide and nano-titanium dioxide respectively, and then add cerium dioxide and nano-titanium dioxide to deionized water in turn. Then, perform ultrasonic dispersion treatment for 10 minutes to obtain a nano-dispersion;

[0013] (3) At room temperature, drop the cerium dioxide dispersion prepared in step (2) into the cetyltrimethylammonium bromide solution prepared in step (1), and stir while dropping to obtain a first mixed solution;

[0014] (4) Adjust the pH of the first mixed solution prepared in step (3), specifically adjust the pH to 9.5, and then stir for 30 minutes to obtain an alkaline solution;

[0015] (5) Add tetraethoxysilane once to the obtained alkaline solution, stir for 5 - 7 hours, then add tetraethoxysilane for the second time, continue to stir for 10 - 12 hours, and then let it stand for 2 hours to obtain a second mixed solution;

[0016] Among them, the mass ratio of the alkaline solution to the first addition of tetraethoxysilane is 50:1;

[0017] The mass ratio of the alkaline solution to the second addition of tetraethoxysilane is 65:1;

[0018] (6) Perform rotary evaporation drying treatment on the second mixed solution obtained in step (5). After drying, obtain a dried product;

[0019] (7) Perform calcination treatment on the dried product obtained in step (6) to obtain a cerium dioxide-coated composite;

[0020] The average particle size of the cerium dioxide-coated composite is 1 μm.

[0021] As a further technical solution: the concentration of the cetyltrimethylammonium bromide solution prepared in step (1) is 0.12 - 0.15 mol / L.

[0022] As a further technical solution: the mass fraction of cerium dioxide in the nano-dispersion in step (2) is 0.2 - 0.5%;

[0023] The mass fraction of nano-titanium dioxide in the nano-dispersion is 5 - 6%.

[0024] As a further technical solution: the volume ratio of the cerium dioxide dispersion to the cetyltrimethylammonium bromide solution in step (3) is 1:10 - 12;

[0025] Among them, the dropping rate is 0.2 ml / s;

[0026] The stirring speed is 120 r / min.

[0027] As a further technical solution: in step (4), ammonia water is used to adjust the pH of the first mixed solution;

[0028] Among them, the mass fraction of ammonia water is 15%.

[0029] As a further technical solution: the calcination temperature in step (7) is 440 - 460 °C;

[0030] The calcination time is 30 min;

[0031] The calcination is carried out in an air atmosphere.

[0032] As a further technical solution: the diamond micropowder used is 1 μm diamond micropowder.

[0033] As a further technical solution: the surfactant is sodium dodecyl sulfate;

[0034] The lubricant is ethylene glycol;

[0035] The chelating agent is sodium ethylenediaminetetraacetate;

[0036] The dispersant is polyacrylic acid.

[0037] A preparation method of a polishing liquid with a photocatalytic auxiliary effect includes the following steps:

[0038] (1) Weigh each raw material by weight parts;

[0039] (2) Add the above raw materials to a mixer in sequence and mix evenly, then it is okay;

[0040] Among them, the mixing is carried out at room temperature;

[0041] The mixing time is 40 min, and the mixing speed is 300 r / min.

[0042] The present invention can effectively cooperate with diamond micropowder by introducing a cerium dioxide-coated composite, improve the polishing quality of the polishing liquid, and at the same time, can also reduce the usage amount of diamond micropowder and lower the cost of the polishing liquid.

[0043] The nano-titanium dioxide contained in the cerium dioxide-coated prepared by the present invention, after being irradiated by ultraviolet light with a certain wavelength, the electrons in the valence band will be excited and transition to the conduction band, and at the same time, positively charged holes will be generated in the valence band, and the holes can adsorb OH on the surface of titanium dioxide particles -It reacts with H2O to produce highly oxidizing hydroxyl radicals ·OH. Through the generated highly oxidizing hydroxyl radicals, oxidation reactions can be carried out on most organic and inorganic substances.

[0044] When the polishing liquid is used for polishing treatment, at the same time, ultraviolet irradiation is carried out. Through the redox reaction between the highly oxidizing holes and hydroxyl radicals ·OH generated by cerium dioxide coating under ultraviolet catalytic conditions and the sample to be polished, and at the same time under the mechanical action of diamond micropowder, chemical reaction and mechanical polishing are carried out simultaneously. With the combined action, a smoother surface with lower surface roughness can be obtained.

[0045] Beneficial effects

[0046] A polishing liquid with photocatalytic assistance prepared by the present invention has high suspension stability, high polishing efficiency, and fast heat dissipation. It can be applied to the polishing processing of various materials such as cemented carbide, ceramics, optical glass, gemstones, and integrated circuits. The present invention uses ultraviolet light for photocatalysis to assist in increasing the kinetic energy of the particles in the polishing liquid. Through the close combination of mechanical action and chemical action, it significantly compensates for the occurrence of large protrusions generated by mechanical action, resulting in an increase in roughness, effectively reducing various defects generated by mechanical action, and greatly improving the surface polishing quality. Description of the drawings

[0047] Figure 1 It is a column chart of the surface roughness test of each group of samples in the examples and comparative examples. Detailed implementation manners

[0048] The technical solutions of the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0049] Example 1

[0050] A polishing liquid with photocatalytic assistance is prepared from the following components by weight: 12 parts of cerium dioxide-coated composite, 6 parts of diamond micropowder, 1.0 part of sodium dodecyl sulfate, 0.2 part of ethylene glycol, 0.1 part of sodium ethylenediaminetetraacetate, 1.2 parts of sodium stearate, 3 parts of polyacrylic acid, 0.3 part of organosilicon defoamer, and 80 parts of deionized water;

[0051] The diamond micropowder used is 1μm diamond micropowder.

[0052] The preparation method of the cerium dioxide-coated composite is as follows:

[0053] (1) First, prepare a cetyltrimethylammonium bromide solution, and then add the cetyltrimethylammonium bromide solution to the reaction kettle; the concentration of the prepared cetyltrimethylammonium bromide solution is 0.12 mol / L.

[0054] (2) Weigh cerium dioxide and nano-titanium dioxide respectively, and then add cerium dioxide and nano-titanium dioxide to deionized water in sequence. Then, perform ultrasonic dispersion treatment for 10 min to obtain a nano-dispersion; the mass fraction of cerium dioxide in the nano-dispersion is 0.2%;

[0055] The mass fraction of nano-titanium dioxide in the nano-dispersion is 5%.

[0056] (3) At room temperature, drop the cerium dioxide dispersion prepared in step (2) into the cetyltrimethylammonium bromide solution prepared in step (1), and stir while dropping to obtain a first mixed solution; the volume ratio of the cerium dioxide dispersion to the cetyltrimethylammonium bromide solution is 1:10;

[0057] Among them, the dropping rate is 0.2 ml / s;

[0058] The stirring speed is 120 r / min.

[0059] (4) Adjust the pH of the first mixed solution prepared in step (3), specifically adjust the pH to 9.5, and then stir for 30 min to obtain an alkaline solution; the pH of the first mixed solution is adjusted using ammonia water;

[0060] Among them, the mass fraction of ammonia water is 15%.

[0061] (5) Add tetraethoxysilane once to the above-obtained alkaline solution, stir for 5 hours, then add tetraethoxysilane for the second time, continue to stir for 10 hours, and then stand for 2 hours to obtain a second mixed solution;

[0062] Among them, the mass ratio of the alkaline solution to the first addition of tetraethoxysilane is 50:1;

[0063] The mass ratio of the alkaline solution to the second addition of tetraethoxysilane is 65:1;

[0064] (6) Perform rotary evaporation drying treatment on the second mixed solution obtained in step (5). After drying, a dried product is obtained;

[0065] (7) Perform calcination treatment on the dried product obtained in step (6) to obtain a cerium dioxide-coated composite; the calcination temperature is 440 °C;

[0066] The calcination time is 30 min;

[0067] The calcination is carried out in an air atmosphere;

[0068] The average particle size of the coated cerium dioxide composite is 1 μm.

[0069] A preparation method of a polishing liquid with photocatalytic auxiliary effect includes the following steps:

[0070] (1) Weigh each raw material by weight parts;

[0071] (2) Add the above raw materials to a mixer in sequence and mix them evenly;

[0072] Among them, the mixing is carried out at room temperature;

[0073] The mixing time is 40 min and the mixing speed is 300 r / min.

[0074] Example 2

[0075] A polishing liquid with photocatalytic auxiliary effect is made of the following components by weight parts: 13 parts of coated cerium dioxide composite, 7 parts of diamond micropowder, 1.2 parts of sodium dodecyl sulfate, 0.25 part of ethylene glycol, 0.2 part of sodium ethylenediaminetetraacetate, 1.4 parts of sodium stearate, 3.5 parts of polyacrylic acid, 0.4 part of organosilicon defoamer, 82 parts of deionized water;

[0076] The diamond micropowder used is 1 μm diamond micropowder.

[0077] The preparation method of the coated cerium dioxide composite is as follows:

[0078] (1) First, prepare a cetyltrimethylammonium bromide solution, and then add the cetyltrimethylammonium bromide solution to a reaction kettle; the concentration of the prepared cetyltrimethylammonium bromide solution is 0.13 mol / L.

[0079] (2) Weigh cerium dioxide and nano-titanium dioxide respectively, and then add cerium dioxide and nano-titanium dioxide to deionized water in sequence, and then carry out ultrasonic dispersion treatment for 10 min to obtain a nano-dispersion; the mass fraction of cerium dioxide in the nano-dispersion is 0.25%;

[0080] The mass fraction of nano-titanium dioxide in the nano-dispersion is 5.5%.

[0081] (3) At room temperature, drop the cerium dioxide dispersion prepared in step (2) into the cetyltrimethylammonium bromide solution prepared in step (1), and stir while dropping to obtain a first mixed solution; the volume ratio of the cerium dioxide dispersion to the cetyltrimethylammonium bromide solution is 1:11;

[0082] Among them, the dropping rate is 0.2 ml / s;

[0083] The stirring speed is 120 r / min.

[0084] (4) Adjust the pH of the first mixed solution prepared in step (3). Specifically, adjust the pH to 9.5, and then stir for 30 min to obtain an alkaline solution. The pH adjustment of the first mixed solution is carried out using ammonia water.

[0085] Among them, the mass fraction of ammonia water is 15%.

[0086] (5) Add tetraethoxysilane once to the above-obtained alkaline solution, stir for 5.5 hours, then add tetraethoxysilane for the second time, continue to stir for 11 hours, and then stand for 2 hours to obtain a second mixed solution.

[0087] Among them, the mass ratio of the alkaline solution to the first addition of tetraethoxysilane is 50:1.

[0088] The mass ratio of the alkaline solution to the second addition of tetraethoxysilane is 65:1.

[0089] (6) Perform rotary evaporation drying on the second mixed solution obtained in step (5). After drying, a dried product is obtained.

[0090] (7) Calcinate the dried product obtained in step (6) to obtain a cerium dioxide-coated composite. The calcination temperature is 445 °C.

[0091] The calcination time is 30 min.

[0092] The calcination is carried out in an air atmosphere.

[0093] The average particle size of the cerium dioxide-coated composite is 1 μm.

[0094] A preparation method of a polishing liquid with a photocatalytic auxiliary effect includes the following steps:

[0095] (1) Weigh each raw material by weight.

[0096] (2) Add the above raw materials to a mixer in sequence and mix them evenly.

[0097] Among them, the mixing is carried out at room temperature.

[0098] The mixing time is 40 min, and the mixing speed is 300 r / min.

[0099] Example 3

[0100] A polishing liquid with photocatalytic assistance is prepared from the following components by weight: 15 parts of cerium dioxide-coated composite, 8 parts of diamond micropowder, 1.3 parts of sodium dodecyl sulfate, 0.28 parts of ethylene glycol, 0.3 parts of sodium ethylenediaminetetraacetate, 1.6 parts of sodium stearate, 3.5 parts of polyacrylic acid, 0.5 parts of silicone defoamer, and 88 parts of deionized water;

[0101] The diamond micropowder used is 1μm diamond micropowder.

[0102] The preparation method of the cerium dioxide-coated composite is as follows:

[0103] (1) First, prepare a cetyltrimethylammonium bromide solution, and then add the cetyltrimethylammonium bromide solution to the reaction kettle; the concentration of the prepared cetyltrimethylammonium bromide solution is 0.14mol / L.

[0104] (2) Weigh cerium dioxide and nano-titanium dioxide respectively, and then add cerium dioxide and nano-titanium dioxide to deionized water in sequence. Then, perform ultrasonic dispersion treatment for 10 minutes to obtain a nano-dispersion; the mass fraction of cerium dioxide in the nano-dispersion is 0.3%;

[0105] The mass fraction of nano-titanium dioxide in the nano-dispersion is 5.5%.

[0106] (3) At room temperature, drop the cerium dioxide dispersion prepared in step (2) into the cetyltrimethylammonium bromide solution prepared in step (1), and stir while dropping to obtain a first mixed solution; the volume ratio of the cerium dioxide dispersion to the cetyltrimethylammonium bromide solution is 1:11;

[0107] Among them, the dropping rate is 0.2ml / s;

[0108] The stirring speed is 120r / min.

[0109] (4) Adjust the pH of the first mixed solution prepared in step (3), specifically adjust the pH to 9.5, and then stir for 30 minutes to obtain an alkaline solution; the pH of the first mixed solution is adjusted using ammonia water;

[0110] Among them, the mass fraction of ammonia water is 15%.

[0111] (5) Add tetraethoxysilane to the above-obtained alkaline solution once, stir for 6 hours, then add tetraethoxysilane for the second time, continue to stir for 11 hours, and then stand for 2 hours to obtain a second mixed solution;

[0112] Among them, the mass ratio of the alkaline solution to the first addition of tetraethoxysilane is 50:1;

[0113] The mass ratio of the alkaline solution to tetraethoxysilane is 65:1;

[0114] (6) Perform rotary evaporation drying on the second mixed solution obtained in step (5). After drying, a dried product is obtained;

[0115] (7) Calcinate the dried product obtained in step (6) to obtain a cerium dioxide-coated composite; the calcination temperature is 450 °C;

[0116] The calcination time is 30 min;

[0117] The calcination is carried out in an air atmosphere;

[0118] The average particle size of the cerium dioxide-coated composite is 1 μm.

[0119] A preparation method of a polishing liquid with a photocatalytic auxiliary effect includes the following steps:

[0120] (1) Weigh each raw material by weight;

[0121] (2) Add the above raw materials to a mixer in sequence and mix evenly;

[0122] The mixing is carried out at room temperature;

[0123] The mixing time is 40 min, and the mixing speed is 300 r / min.

[0124] Example 4

[0125] A polishing liquid with a photocatalytic auxiliary effect is made of the following components by weight: 18 parts of cerium dioxide-coated composite, 9 parts of diamond micropowder, 1.5 parts of sodium dodecyl sulfate, 0.3 part of ethylene glycol, 0.4 part of sodium ethylenediaminetetraacetate, 1.8 parts of sodium stearate, 4 parts of polyacrylic acid, 0.6 part of organosilicon defoamer, and 90 parts of deionized water;

[0126] The diamond micropowder used is 1-μm diamond micropowder.

[0127] The preparation method of the cerium dioxide-coated composite is as follows:

[0128] (1) First, prepare a cetyltrimethylammonium bromide solution, and then add the cetyltrimethylammonium bromide solution to a reaction kettle; the concentration of the cetyltrimethylammonium bromide solution prepared is 0.15 mol / L.

[0129] (2) Weigh cerium dioxide and nano-titanium dioxide respectively, and then add cerium dioxide and nano-titanium dioxide to deionized water in sequence. Then, perform ultrasonic dispersion treatment for 10 min to obtain a nano-dispersion; the mass fraction of cerium dioxide in the nano-dispersion is 0.5%;

[0130] The mass fraction of nano-titanium dioxide in the nano-dispersion is 6%.

[0131] (3) At room temperature, the cerium dioxide dispersion prepared in step (2) is dropped into the cetyltrimethylammonium bromide solution prepared in step (1), and stirred while dropping to obtain a first mixed solution; the volume ratio of the cerium dioxide dispersion to the cetyltrimethylammonium bromide solution is 1:12;

[0132] Among them, the dropping rate is 0.2 ml / s;

[0133] The stirring speed is 120 r / min.

[0134] (4) Adjust the pH of the first mixed solution prepared in step (3), specifically adjust the pH to 9.5, and then stir for 30 min to obtain an alkaline solution; the pH of the first mixed solution is adjusted using ammonia water;

[0135] Among them, the mass fraction of ammonia water is 15%.

[0136] (5) Add tetraethoxysilane once to the above-mentioned obtained alkaline solution, stir for 7 hours, then add tetraethoxysilane twice, continue to stir for 12 hours, and then stand for 2 hours to obtain a second mixed solution;

[0137] Among them, the mass ratio of the alkaline solution to the first addition of tetraethoxysilane is 50:1;

[0138] The mass ratio of the alkaline solution to the second addition of tetraethoxysilane is 65:1;

[0139] (6) Perform rotary evaporation drying treatment on the second mixed solution obtained in step (5), and after drying, obtain a dried product;

[0140] (7) Perform calcination treatment on the dried product obtained in step (6) to obtain a cerium dioxide-coated composite; the calcination temperature is 460 °C;

[0141] The calcination time is 30 min;

[0142] The calcination is carried out in an air atmosphere;

[0143] The average particle size of the cerium dioxide-coated composite is 1 μm.

[0144] A preparation method of a polishing liquid with a photocatalytic auxiliary effect includes the following steps:

[0145] (1) Weigh each raw material by weight;

[0146] (2) Add the above raw materials to a mixer in sequence and mix them evenly.

[0147] The mixing is carried out at room temperature;

[0148] The mixing time is 40 min and the mixing rotation speed is 300 r / min.

[0149] Comparative Example 1:

[0150] On the basis of Example 1, the coated cerium dioxide composite is not added to the components, and the rest of the technical solutions remain unchanged.

[0151] Comparative Example 2:

[0152] On the basis of Example 1, an equal amount of cerium dioxide is replaced with the coated cerium dioxide composite in the components, and the rest of the technical solutions remain unchanged.

[0153] Test

[0154] The polishing liquids of the examples and comparative examples are used to polish 6-inch gallium arsenide (GaAs) wafers with an AMAT Reflexion LK type polishing machine produced by Applied Materials, Inc. of the United States;

[0155] The flow rate of the polishing liquid is 180 mL / min, the pressure is 1.5 psi, the platform rotation speed is 70 rpm, the rotation speed of the chuck head is 55 rpm, and the polishing time is 15 min;

[0156] A mercury lamp type light source (350 nm) with a relatively large energy in the ultraviolet effective region is selected for irradiation in the test;

[0157] The polishing effects of the polishing liquids of the examples and comparative examples are compared:

[0158] Table 1

[0159] Polishing effect Example 1 No obvious scratches Example 2 No obvious scratches Example 3 No obvious scratches Example 4 No obvious scratches Comparative example 1 Obvious scratches Comparative example 2 Slight scratches

[0160] As can be seen from Table 1, the polishing liquid prepared by the present invention can greatly improve the polishing effect of the polishing liquid, can effectively reduce the scratches on the surface of the specimen, and improve the surface quality.

[0161] The surface roughness of the specimen after the above polishing treatment is tested;

[0162] Table 2

[0163] Ra μm Example 1 0.025 Example 2 0.028 Example 3 0.030 Example 4 0.022 Comparative example 1 0.183 Comparative example 2 0.104

[0164] As can be seen from Table 2, it can be seen that the polishing liquid prepared by the present invention can significantly reduce the surface roughness of the polished specimen.

[0165] Taking Example 2 as the basic specimen, the influence of different ultraviolet wavelengths on the surface roughness of the specimen is compared;

[0166] Table 3

[0167] Ultraviolet wavelength nm Ra μm 200 0.062 250 0.051 300 0.044 350 0.028 400 0.037 450 0.041

[0168] As can be seen from Table 3, with the increase of the external wavelength of the qualification, the surface roughness of the polished surface of the polishing liquid first decreases and then increases.

[0169] The column charts of the surface roughness of the test samples of each group of the examples and comparative examples are as Figure 1 .

[0170] The above are only the preferred embodiments of the present invention, but the present invention is not limited to the scope of the embodiments shown. Any changes made according to the concept of the present invention, or equivalent embodiments modified into equivalent changes, still within the spirit covered by the specification, shall be within the protection scope of the present invention.

Claims

1. A polishing liquid with photocatalytic assistance function, characterized in that, It is made of the following components by weight parts: 12 - 18 parts of coated cerium dioxide composite, 6 - 9 parts of diamond micropowder, 1.0 - 1.5 parts of sodium dodecyl sulfate, 0.2 - 0.3 parts of ethylene glycol, 0.1 - 0.4 parts of sodium ethylenediaminetetraacetate, 1.2 - 1.8 parts of sodium stearate, 3 - 4 parts of polyacrylic acid, 0.3 - 0.6 parts of organosilicon defoamer, and 80 - 90 parts of deionized water; The preparation method of the coated cerium dioxide composite is as follows: (1) First, prepare a cetyltrimethylammonium bromide solution, and then add the cetyltrimethylammonium bromide solution to the reaction kettle; (2) Weigh cerium dioxide and nano - titanium dioxide respectively, and then add cerium dioxide and nano - titanium dioxide to deionized water in sequence. Then, perform ultrasonic dispersion treatment for 10 min to obtain a nano - dispersion liquid; (3) At room temperature, drop the cerium dioxide dispersion liquid prepared in step (2) into the cetyltrimethylammonium bromide solution prepared in step (1), and stir while dropping to obtain a first mixed liquid; (4) Adjust the pH of the first mixed liquid prepared in step (3), specifically adjust the pH to 9.5, and then stir for 30 min to obtain an alkaline liquid; (5) Add tetraethoxysilane once to the obtained alkaline liquid, stir for 5 - 7 hours, then add tetraethoxysilane for the second time, continue to stir for 10 - 12 hours, and then let it stand for 2 hours to obtain a second mixed liquid; Among them, the mass ratio of the alkaline liquid to the first - added tetraethoxysilane is 50:1; The mass ratio of the alkaline liquid to the second - added tetraethoxysilane is 65:1; (6) Perform rotary evaporation and drying treatment on the second mixed liquid obtained in step (5). After drying, obtain a dried product; (7) Perform calcination treatment on the dried product obtained in step (6) to obtain a coated cerium dioxide composite; The average particle size of the coated cerium dioxide composite is 1 μm.

2. The polishing liquid with photocatalytic assistance function according to claim 1, wherein: The concentration of the cetyltrimethylammonium bromide solution prepared in step (1) is 0.12 - 0.15 mol / L.

3. A polishing liquid with a photocatalytic auxiliary effect according to claim 1, characterized in that: In step (2), the mass fraction of cerium dioxide in the nano - dispersion liquid is 0.2 - 0.5%; The mass fraction of nano - titanium dioxide in the nano - dispersion liquid is 5 - 6%.

4. A polishing liquid with photocatalytic assistance according to claim 1, characterized in that: The volume ratio of the cerium dioxide dispersion liquid to the cetyltrimethylammonium bromide solution in step (3) is 1:10 - 12; Among them, the dropping rate is 0.2 ml / s; The stirring speed is 120 r / min.

5. A polishing liquid with a photocatalytic auxiliary effect according to claim 1, characterized in that: In step (4), the pH of the first mixed liquid is adjusted using ammonia water; Among them, the mass fraction of ammonia water is 15%.

6. A polishing liquid with a photocatalytic auxiliary effect according to claim 1, characterized in that: In step (7), the calcination temperature is 440 - 460 °C; The calcination time is 30 min; The calcination is carried out in an air atmosphere.

7. A polishing liquid with a photocatalytic auxiliary effect according to claim 1, characterized in that: The diamond micropowder used is 1 - μm diamond micropowder.

8. The preparation method of a polishing liquid with photocatalytic auxiliary efficacy according to any one of claims 1 or 7, characterized in that: It includes the following steps: (1) Weigh each raw material by weight parts; (2) Add the above - mentioned raw materials to a mixer in sequence and mix them evenly; Among them, the mixing is carried out at room temperature; The mixing time is 40 min, and the mixing speed is 300 r / min.

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