A microalgae-based polishing abrasive, a polishing liquid containing the same, a preparation method thereof, and uses thereof

Abstract

The present invention provides a microalgae-based polishing abrasive, a polishing liquid containing the same, a preparation method thereof and uses thereof. The preparation method of the microalgae-based polishing abrasive comprises the following steps: adding microalgae into a phosphate buffer solution to obtain a microalgae solution; adding an abrasive into the microalgae solution and stirring to obtain the microalgae-based polishing abrasive. The present invention also discloses a polishing liquid containing the microalgae-based polishing abrasive, which comprises the following components in parts by weight: 1-30 parts of the microalgae-based polishing abrasive; 1-20 parts of an oxidant; 1-20 parts of a pH regulator; 0.1-5 parts of a catalyst; 0.1-10 parts of a dispersant; and 20-70 parts of deionized water. The microalgae-based polishing abrasive prepared by the present invention has a special core-shell structure. When using the polishing liquid containing the microalgae-based polishing abrasive to polish silicon carbide, it has the advantages of high removal rate and low scratching, and the polishing liquid is also applicable to semiconductor materials such as gallium nitride and sapphire.

Description

Technical Field

[0001] The present invention relates to polishing technology, and in particular to a microalgae-based polishing abrasive, a polishing liquid containing the same, a preparation method thereof, and uses thereof. Background Art

[0002] The third-generation semiconductor materials such as silicon carbide (SiC) are all high-temperature ceramic materials, and have two remarkable characteristics: high hardness (Mohs hardness 9.2) and chemical inertness. The SiC material has high hardness, and the friction removal efficiency of ordinary hardness abrasive grains on SiC is low; moreover, the sharp edges and corners of the abrasive grains are easily passivated rapidly by the hard SiC, and the polishing efficiency decays rapidly with time, and the process stability is poor. The diamond abrasive grains have high friction removal efficiency, but cause serious damage to the SiC surface, and the surface quality of the product cannot meet the strict requirements for surface quality in the production of electronic devices. SiC has extremely strong chemical inertness, the reaction activity of conventional chemical reagents with it is extremely low, the reaction rate is very slow, it is difficult to rapidly soften the SiC surface, and the effect of chemical polishing is poor.

[0003] Some SiC polishing liquids are disclosed in the prior art. For example:

[0004] CN114940886A discloses nano-aluminum oxide abrasive grains, a preparation method, applications, and a silicon carbide polishing liquid containing the abrasive grains. The polishing liquid is composed of the following components in weight percentage concentration: nano-aluminum oxide abrasive grains 1-50%, surfactant 0.05-5%, oxidant 0.2-10%, pH regulator 0.02-2%, and the balance of aqueous medium. The used aluminum oxide abrasive grains have a small particle size and good surface accuracy, improving the polishing efficiency and accuracy.

[0005] CN111574927A discloses a silicon carbide polishing liquid containing a reducing agent. The polishing liquid is composed of abrasive grains, a reducing agent, nitric acid, and deionized water, and the pH value is 1-7. The polishing liquid has the advantages of high cutting rate, stable surface quality, long cycle service life, and no problems of volatility and heavy metal pollution, and is easy to store for a long time, and is especially suitable for the surface polishing of ultra-precision optical devices or semiconductor power devices with difficult-to-process silicon-containing surfaces.

[0006] WO2020087721A1 discloses a silicon carbide chemical mechanical polishing liquid with improved pH stability. The polishing liquid includes an oxidant, a high-hardness abrasive, and a pH stabilizer, and the pH stabilizer is aluminum nitrate. The pH value of the polishing liquid is more stable during the chemical mechanical polishing process, and the polishing liquid is not prone to hard agglomeration and is pollution-free to the environment.

[0007] There are problems of low SiC removal rate and serious scratching to varying degrees in the above polishing liquid technologies. Therefore, it is necessary to develop a SiC polishing liquid with high removal rate and low scratching. Summary of the Invention

[0008] The object of the present invention is to propose a preparation method of microalgae-based polishing abrasive aiming at the problems of low SiC removal rate and serious scratching existing in existing polishing fluids to varying degrees. The microalgae-based polishing abrasive prepared by this method has a special core-shell structure. When using a polishing fluid containing the microalgae-based polishing abrasive to polish silicon carbide, it has the advantages of high removal rate and low scratching, and this polishing fluid is also applicable to semiconductor materials such as gallium nitride and sapphire.

[0009] It should be noted that in the present invention, unless otherwise specified, the specific meaning of "including" involving compositional limitations and descriptions includes both the open "including", "containing" and their similar meanings, and also the closed "consisting of" and their similar meanings.

[0010] To achieve the above object, the technical solution adopted by the present invention is: a preparation method of microalgae-based polishing abrasive, including the following steps:

[0011] Add microalgae to a phosphate buffer solution and mix to obtain a microalgae solution; add abrasive to the microalgae solution and stir to obtain a microalgae-based polishing abrasive. The phosphate buffer solution has a salt balance effect and can adjust the solution to a pH value of 7.0 - 8.0 to prevent the solution from destroying the structure and biological characteristics of biological proteins.

[0012] Further, the microalgae is one or more of cyanobacteria, chlorella, spirulina and haematococcus.

[0013] Further, the microalgae is preferably chlorella.

[0014] Further, the cultivation steps of the microalgae are as follows: inoculate the microalgae in a culture medium, keep the environmental temperature at 25 - 30 °C, and the light intensity at 35 - 40 μmol / m 2 s; separate the mixture of the above microalgae and the culture medium by a centrifuge to extract the microalgae.

[0015] Further, the specific reagents in the culture medium are as follows:

[0016] Sodium nitrate, dipotassium hydrogen phosphate, magnesium sulfate heptahydrate, calcium chloride dihydrate, citric acid monohydrate, ammonium ferric citrate, disodium ethylenediaminetetraacetate, sodium carbonate, trace elements; the corresponding stock solution concentrations are: 15 g / L, 4 g / L, 7.5 g / L, 3.6 g / L, 0.6 g / L, 0.6 g / L, 0.1 g / L, 2 g / L; among them, the functions of potassium dihydrogen phosphate, citric acid monohydrate, ammonium ferric citrate and disodium ethylenediaminetetraacetate are to promote the reproduction and growth of microalgae; the functions of sodium nitrate, magnesium sulfate heptahydrate, calcium chloride dihydrate and trace elements are to provide nutrients for the growth of microalgae; the function of sodium carbonate is to adjust the pH value of the culture solution.

[0017] Further, the addition amount of sodium nitrate is 100 - 120 mL / L.

[0018] Further, the addition amount of sodium nitrate is preferably 100 - 105 mL / L.

[0019] Further, the addition amount of dipotassium hydrogen phosphate is 10 - 15 mL / L.

[0020] Further, the addition amount of dipotassium hydrogen phosphate is preferably 10 - 12 mL / L.

[0021] Further, the addition amount of magnesium sulfate heptahydrate is 10 - 15 mL / L.

[0022] Further, the addition amount of magnesium sulfate heptahydrate is preferably 10 - 12 mL / L.

[0023] Further, the addition amount of calcium chloride dihydrate is 10 - 15 mL / L.

[0024] Further, the addition amount of calcium chloride dihydrate is preferably 10 - 12 mL / L.

[0025] Further, the addition amount of citric acid monohydrate is 10 - 15 mL / L.

[0026] Further, the addition amount of citric acid monohydrate is preferably 10 - 12 mL / L

[0027] Further, the addition amount of ammonium ferric citrate is 10 - 15 mL / L.

[0028] Further, the addition amount of ammonium ferric citrate is preferably 10 - 12 mL / L.

[0029] Further, the addition amount of disodium ethylenediaminetetraacetate is 10 - 15 mL / L.

[0030] Further, the addition amount of disodium ethylenediaminetetraacetate is preferably 10 - 12 mL / L.

[0031] Further, the addition amount of sodium carbonate is 10 - 15 mL / L.

[0032] Further, the addition amount of sodium carbonate is preferably 10 - 12 mL / L.

[0033] Further, the addition amount of trace elements is 1 - 1.5 mL / L.

[0034] Further, the trace elements include the following components: boric acid, manganese chloride tetrahydrate, zinc sulfate heptahydrate, sodium molybdate dihydrate, copper sulfate pentahydrate, and cobalt nitrate hexahydrate, and their concentrations are respectively: 2.86 g / L, 1.86 g / L, 0.22 g / L, 0.39 g / L, 0.08 g / L, 0.05 g / L.

[0035] Further, before adding the microalgae to the phosphate buffer solution for mixing, it is washed with NaCl solution to maintain the osmotic pressure of the microalgae.

[0036] Further, the concentration of the NaCl solution is 0.01 - 0.03 M.

[0037] Further, the concentration of the NaCl solution is preferably 0.02 - 0.025 M.

[0038] Further, the concentration of the phosphate buffer solution is 0.1 - 0.2 M, pH = 7.0 - 8.0.

[0039] Further, the concentration of the phosphate buffer solution is preferably 0.1 - 0.15 M, pH = 7.0 - 7.5.

[0040] Further, the concentration of microalgae in the microalgae solution is 3×10 6 -4×10 6 cells / mL.

[0041] Further, the concentration of microalgae in the microalgae solution is preferably 3×10 6 -3.5×10 6 cells / mL.

[0042] Further, the abrasive is one or more of silicon dioxide, cerium oxide, diamond, silicon carbide, boron nitride, zirconia, and alumina.

[0043] Further, the abrasive is preferably alumina.

[0044] Further, the particle size of the abrasive is 0.01 - 0.9 μm.

[0045] Further, the particle size of the abrasive is preferably 0.02 - 0.3 μm.

[0046] Further, the concentration of the abrasive in the microalgae-based polishing abrasive is 0.04 - 0.06 g / mL.

[0047] Further, the concentration of the abrasive in the microalgae-based polishing abrasive is preferably 0.05 - 0.06 g / mL.

[0048] Further, the stirring conditions are: stirring at a rotation speed of 40 - 60 r / min for 1 - 2 h.

[0049] Further, the stirring conditions are preferably: stirring at a rotation speed of 45 - 60 r / min for 1.2 - 1.5 h.

[0050] Another object of the present invention also discloses a microalgae-based polishing abrasive prepared by the above preparation method.

[0051] Another object of the present invention also discloses the use of a microalgae-based polishing abrasive in the field of polishing liquids.

[0052] Another object of the present invention also discloses a polishing liquid containing a microalgae-based polishing abrasive, comprising the above microalgae-based polishing abrasive.

[0053] Further, the polishing liquid containing a microalgae-based polishing abrasive comprises the following components in weight ratios:

[0054]

[0055] Further, the microalgae-based polishing abrasive is 10 - 25 parts.

[0056] Further, the oxidant is one or more of hydrogen peroxide, sodium periodate, potassium permanganate, potassium persulfate, and potassium bromate.

[0057] Further, the oxidant is preferably potassium bromate.

[0058] Further, the oxidant is 5 - 15 parts.

[0059] Further, the pH regulator is an acidic regulator.

[0060] Further, the acidic regulator is one or more of hydrochloric acid, sulfuric acid, nitric acid, oxalic acid, malic acid, and phosphoric acid.

[0061] Further, the pH regulator is preferably nitric acid.

[0062] Further, the pH regulator is 3 - 10 parts.

[0063] Further, the mass ratio of the oxidant to the pH regulator is 5 - 1:1 - 2, which is more conducive to enhancing the oxidation ability of potassium bromide, improving the polishing effect, and at the same time, the trace elements therein can provide nutrients for microalgae.

[0064] Further, the mass ratio of the oxidant to the pH regulator is preferably 3 - 1:1.

[0065] Further, the mass ratio of the oxidant to the pH regulator is more preferably 1.5:1.

[0066] Further, the catalyst is one or more of titanium dioxide, zinc oxide, tin oxide, and zirconium dioxide.

[0067] Further, the catalyst is preferably titanium dioxide.

[0068] Further, the amount of the catalyst is 1 - 3 parts.

[0069] Further, the dispersant is an aqueous dispersant.

[0070] Further, the aqueous dispersant is one or more of polyethylene glycol 400, glycerol, polyacrylic acid, sodium polyacrylate, sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate.

[0071] Further, the molecular weight of the polyacrylic acid is 1000 - 3000.

[0072] Further, the molecular weight of the sodium polyacrylate is 1000 - 3000.

[0073] Further, the aqueous dispersant is preferably sodium dodecylsulfonate.

[0074] Further, the amount of the dispersant is 1 - 5 parts.

[0075] Further, the pH of the polishing liquid is 5 - 6.

[0076] Further, the preferred pH of the polishing liquid is 5 - 5.5.

[0077] Further, the amount of deionized water is 30 - 50 parts.

[0078] Another object of the present invention also discloses a method for preparing a polishing liquid containing microalgae-based polishing abrasive, comprising the following steps: First, mix and stir the components except the microalgae-based polishing abrasive, and then add the microalgae-based polishing abrasive to the above solution and stir to prepare a polishing liquid containing the microalgae-based polishing abrasive.

[0079] Further, first mix the components except the microalgae-based polishing abrasive and stir at 30 - 100 r / min for 30 - 90 min.

[0080] Further, first mix the components except the microalgae-based polishing abrasive and stir at 45 - 80 r / min for 45 - 80 min.

[0081] Further, then add the microalgae-based polishing abrasive to the above solution and stir at 30 - 100 r / min for 10 - 50 min.

[0082] Further, then add the microalgae-based polishing abrasive to the above solution and stir at 45 - 80 r / min for 15 - 45 min.

[0083] Another object of the present invention also discloses the use of a polishing liquid containing microalgae-based polishing abrasive in the fields of polishing silicon carbide, sapphire and gallium nitride.

[0084] Furthermore, the process of polishing silicon carbide with a polishing liquid containing microalgae-based polishing abrasive includes the following steps:

[0085] Step 1: Dilute the polishing liquid containing microalgae-based polishing abrasive by 2 - 5 times for standby;

[0086] Step 2: Set the ultraviolet light to irradiate the surface of silicon carbide (4 inches), with a wavelength of 100 - 400 nm;

[0087] Step 3: Set the rotation speed of the polishing machine to 50 - 100 r / min, the pressure to 15 - 30 kg, the flow rate to 5 - 200 mL / min, and the polishing time to 10 - 800 min.

[0088] The microalgae-based polishing abrasive, the polishing liquid containing the same, its preparation method and uses of the present invention have the following advantages compared with the prior art:

[0089] 1. The present invention utilizes the advantages of microalgae being non-toxic, harmless and having a negatively charged surface, and combines with positively charged abrasives through electrostatic interaction to synthesize microalgae-based polishing abrasive in one step. This abrasive has the advantages of simple synthesis method and environmental friendliness.

[0090] 2. During the polishing process of silicon carbide, due to the easy agglomeration and large hardness of the abrasive, it is extremely easy to scratch silicon carbide. The microalgae-based polishing abrasive prepared by the present invention has a core-shell structure and has the characteristics of "soft inside and hard outside". During polishing, the soft microalgae inside can play a buffering role to reduce scratches; at the same time, the positively charged abrasive can be anchored on the surface of the microalgae, and the charge carried by itself is offset through electrostatic interaction, making the microalgae-based polishing abrasive prepared by the present invention have better dispersibility, and can better cooperate with the dispersant to achieve the dispersion effect and is not easy to agglomerate.

[0091] 3. Since the microalgae are tightly wrapped (attached Figure 1 It can be seen that around many broken and small abrasives, there are extremely obvious and many smooth and regular large abrasives. The inside of these large abrasives is the microalgae evenly wrapped by the abrasives, and the two form a microalgae-based polishing abrasive). The components such as catalysts and oxidants added in the present invention will not have an adverse effect on the microalgae. Moreover, the potassium bromate used as the oxidant in the present invention can maintain the activity of the microalgae, and the stability of the polishing abrasive can be achieved without additional additives.

[0092] 4. The pH regulator and the oxidant in the present invention act synergistically. The H + provided by nitric acid can react with BrO3 in potassium bromate- Combined, it further enhances the oxidation ability of potassium bromate; meanwhile, during the polishing process, the nitrogen element in nitric acid can form nitrides and enter the interior of the microalgae-based polishing abrasive, providing nutrients for the microalgae, maintaining the activity of the microalgae, and ensuring the "soft inside and hard outside" characteristic of the abrasive.

[0093] 5. The catalyst in the present invention can react on the surface layer of SiC to generate a relatively soft oxide layer, and then use the mechanical polishing action of the abrasive to remove the oxide layer to obtain a high-quality surface.

[0094] Therefore, the polishing liquid of the present invention has very good application prospects and the potential for large-scale industrial promotion in the field of silicon carbide polishing. Description of the Drawings

[0095] Figure 1 It is the SEM image of the microalgae-based polishing abrasive a for polishing abrasive.

[0096] Figure 2 It is the surface scratch image after polishing a silicon carbide wafer with the polishing liquid of Comparative Example 1.

[0097] Figure 3 It is the surface scratch image after polishing a silicon carbide wafer with the polishing liquid of Example 1.

[0098] Figure 4 It is the roughness test site map of the silicon carbide wafer. Detailed Embodiments

[0099] The present invention is further described below in conjunction with embodiments:

[0100] Polishing abrasive a: Chlorella-based polishing abrasive

[0101] Inoculate Chlorella in the culture medium, keep the environmental temperature at 25°C, and the light intensity at 36 μmol / m 2 s; separate the mixture of Chlorella and the culture medium by a centrifuge to extract Chlorella.

[0102] The specific components in the culture medium are as follows: sodium nitrate, dipotassium hydrogen phosphate, magnesium sulfate heptahydrate, calcium chloride dihydrate, citric acid monohydrate, ammonium ferric citrate, disodium ethylenediaminetetraacetate, sodium carbonate, trace elements; the corresponding mother liquor concentrations are: 15 g / L, 4 g / L, 7.5 g / L, 3.6 g / L, 0.6 g / L, 0.6 g / L, 0.1 g / L, 2 g / L; the specific addition amounts are: 102 mL / L, 11 mL / L, 11.5 mL / L, 11 mL / L, 11 mL / L, 10 mL / L, 11 mL / L, 10 mL / L, 1.2 mL / L; the specific components of the trace elements are: boric acid, manganese chloride tetrahydrate, zinc sulfate heptahydrate, sodium molybdate dihydrate, copper sulfate pentahydrate, and cobalt nitrate hexahydrate, and their concentrations are: 2.86 g / L, 1.86 g / L, 0.22 g / L, 0.39 g / L, 0.08 g / L, 0.05 g / L.

[0103] After the cultivation is completed, it is washed with 0.025 M NaCl solution to maintain the osmotic pressure of Chlorella. Subsequently, the Chlorella is placed into a sodium phosphate buffer solution with a concentration of 0.15 M and a pH of 7.0 to obtain a microalgae solution.

[0104] Take 500 mL of the above microalgae solution, and place 25 g of alumina abrasive with a particle size of 0.2 μm into the microalgae solution. Stir the above mixed solution at 50 r / min for 1.3 h to obtain a Chlorella-based polishing abrasive.

[0105] Polishing abrasive b: Cyanobacteria-based polishing abrasive

[0106] This example is basically the same as Example a, except that the Chlorella in polishing abrasive a is replaced with cyanobacteria, and the other steps remain unchanged.

[0107] Polishing abrasive c: Spirulina-based polishing abrasive

[0108] This example is basically the same as Example a, except that the Chlorella in polishing abrasive a is replaced with spirulina, and the other steps remain unchanged.

[0109] Polishing abrasive d: Haematococcus-based polishing abrasive

[0110] This example is basically the same as Example a, except that the Chlorella in polishing abrasive a is replaced with Haematococcus, and the other steps remain unchanged.

[0111] Polishing abrasive e: Chlorella-based polishing abrasive + 0.2 μm silica abrasive

[0112] This example is basically the same as Example a, except that the 0.2 μm alumina in polishing abrasive a is replaced with 0.2 μm silica, and the other steps remain unchanged.

[0113] Figure 1SEM image of the microalgae-based polishing abrasive a for polishing; From Figure 1 It can be seen that abrasives with smaller particle sizes are combined with microalgae through electrostatic interaction (the microalgae are evenly wrapped inside the abrasives. Although the microalgae cannot be directly seen, their smooth and regular appearance can indirectly reflect the degree of wrapping), forming larger abrasives; due to the cancellation of charges, the large abrasives with a "soft inside and hard outside" structure have better dispersibility, can better cooperate with the dispersant to achieve the dispersion effect, and are not prone to agglomeration.

[0114] Examples 1-12

[0115] Examples 1-12 disclose various polishing liquids containing microalgae-based polishing abrasives, and the components and mass ratios thereof are shown in Table 1. The preparation method is as follows: First, mix the components except the microalgae-based polishing abrasive and stir at 60 r / min for 60 min, then add the microalgae-based polishing abrasive to the above solution and stir at 60 r / min for 30 min to prepare the polishing liquid containing the microalgae-based polishing abrasive.

[0116] Table 1 Components and mass ratios of the polishing liquids containing microalgae-based polishing abrasives in Examples 1-12

[0117]

[0118] Comparative Examples 1-5

[0119] Comparative Examples 1-5 disclose various polishing liquids, and the components and weight ratios thereof are shown in Table 2. The preparation method is the same as that of Example 1.

[0120] Table 2 Components and weight ratios of the polishing liquids in Comparative Examples 1-5

[0121]

[0122] Performance testing and description

[0123] Next, the various performances of the above examples and comparative examples are tested as follows:

[0124] Figure 2 Figure showing the surface scratches of a silicon carbide wafer polished with the polishing liquid of Comparative Example 1; From Figure 2 It can be seen that there are many surface scratches on the silicon carbide polished with the polishing liquid of Comparative Example 1, and the depth is relatively deep, making it difficult to meet the industrial requirements.

[0125] Figure 3 Figure showing the surface scratches of a silicon carbide wafer polished with the polishing liquid of Example 1; From Figure 3 It can be seen that there are very few and not obvious surface scratches on the silicon carbide polished with the polishing liquid of Example 1 of the present invention.

[0126] Figure 4 It is a map of the roughness test sites of the silicon carbide wafer.

[0127] The test results of Examples 1-12 and Comparative Examples 1-5 are shown in Table 3. As can be seen from Table 3, in Example 1, the H provided by nitric acid + can combine with BrO3 in potassium bromate - , further enhancing the oxidation ability of potassium bromate. Therefore, the removal rate in Example 1 is the highest among all examples. Moreover, during the polishing process, the nitrogen element in nitric acid can form nitrides, providing nutrients for microalgae and maintaining the activity of microalgae to the greatest extent, enabling the microalgae-based abrasive to always maintain the characteristic of "soft inside and hard outside", enhancing the suspension time of the polishing liquid, resulting in a high surface quality and no scratches after polishing. In Comparative Example 1, diamond abrasive was used, and its rigidity is much greater than that of the microalgae-based abrasive. Therefore, the removal rate in Comparative Example 1 is higher than that in the examples. Correspondingly, however, the roughness of the silicon carbide surface is very large and the scratches are obvious. In Comparative Examples 2-5, although the microalgae-based abrasive was used, due to the lack of different components in the polishing liquid, the synergistic effect between the microalgae-based abrasive and other components was not exerted, and the optimal microalgae growth and polishing conditions were not provided. Therefore, the surface quality of the polished silicon carbide is much lower than that in Example 1.

[0128] Table 3 Test results of Examples 1-12 and Comparative Examples 1-5

[0129]

[0130] Wherein:

[0131] The method for the performance 1 polishing removal rate is:

[0132] MRR is the removal rate (nm / h), m1 (g) is the mass of the wafer before polishing, m2 (g) is the mass of the wafer after polishing, t (h) is the polishing time, ρ is the density of the silicon carbide wafer (g / cm 3 ), s is the area of the silicon carbide (cm 2 ), formula: MRR = (m1 - m2) * 10 7 / ρst.

[0133] The method for testing the performance 2 surface quality after polishing is:

[0134] After cleaning the polished wafer, observe it with a microscope.

[0135] The method for testing the performance 3 suspension property is:

[0136] Shake the prepared polishing liquid well and let it stand, and observe the suspension time.

[0137] The method for testing the performance 4 roughness is:

[0138] After cleaning and drying the polished silicon carbide wafer with ethanol, perform three roughness tests at five points on the front and back of the silicon carbide wafer and take the average value to determine the roughness of the silicon carbide wafer.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. 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 polishing liquid containing microalgae-based polishing abrasive, characterized in that, Comprising the following components in the following weight ratios: Microalgae-based polishing abrasive: 1 - 30 parts; Oxidizing agent: 1 - 20 parts; pH regulator: 1 - 20 parts; Catalyst: 0.1 - 5 parts; Dispersant: 0.1 - 10 parts; Deionized water: 20 - 70 parts; The oxidizing agent is one or more of hydrogen peroxide, sodium periodate, potassium permanganate, potassium persulfate, and potassium bromate; The pH regulator is an acidic regulator; The catalyst is one or more of titanium dioxide, zinc oxide, tin oxide, and zirconium dioxide; The dispersant is one or more of polyethylene glycol 400, glycerol, polyacrylic acid, sodium polyacrylate, sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate; The microalgae-based polishing abrasive is prepared by the following method: Inoculate microalgae into a culture medium, maintain the environmental temperature at 25-30 °C, and the light intensity at 35-40 μmol / m 2 s; separate the mixture of the above-mentioned microalgae and the culture medium by a centrifuge to extract the microalgae; Adding microalgae to a phosphate buffer solution to obtain a microalgae solution; adding an abrasive to the microalgae solution and stirring to obtain the microalgae-based polishing abrasive; The microalgae is one or more of cyanobacteria, chlorella, spirulina, and haematococcus pluvialis; The abrasive is one or more of silicon dioxide, cerium oxide, diamond, silicon carbide, boron nitride, zirconium oxide, and aluminum oxide.

2. The polishing liquid containing microalgae-based polishing abrasive according to claim 1, characterized in that, The pH of the polishing liquid is 5 - 6.

3. A method for preparing the polishing liquid containing microalgae-based polishing abrasive according to claim 1 or 2, characterized in that, Including the following steps: First, mix and stir the components except the microalgae-based polishing abrasive, and then add the microalgae-based polishing abrasive to the above solution and stir to prepare a polishing liquid containing the microalgae-based polishing abrasive.

4. Use of the polishing liquid containing microalgae-based polishing abrasive according to claim 1 or 2 in the field of polishing silicon carbide, sapphire and gallium nitride.

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