Silicon carbide CMP fine polishing solution and preparation method thereof

Abstract

The invention relates to a silicon carbide CMP (chemical mechanical polishing) fine polishing solution and a preparation method thereof, the silicon carbide CMP fine polishing solution comprises the following components: a silicon oxide abrasive, a catalyst, a catalyst activator, a dispersant, an oxidant, a pH regulator and deionized water, and the pH is 8.5-11.0; the silicon oxide grinding fluid comprises the following components in percentage by weight: 5 to 20 percent of silicon oxide grinding material, 1 to 5 percent of catalyst, 0.1 to 2 percent of catalyst activating agent, 0.1 to 1 percent of dispersing agent, 0.5 to 5 percent of oxidizing agent, 0.1 to 0.5 percent of pH (Potential of Hydrogen) regulator and the balance of deionized water. The prepared polishing solution has higher machining efficiency and better surface quality, is simple in component, easy to prepare, not prone to crystallization and bubbling in the polishing process, free of corrosion to a machine table, good in economic benefit, easy to store, capable of being recycled and convenient to clean after being used, has good technological performance and is suitable for popularization and application. The method is suitable for sub-nanometer polishing of the surface of the silicon carbide wafer substrate.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor wafer polishing, and more particularly, to a silicon carbide CMP fine polishing liquid and a preparation method thereof. Background Art

[0002] Single crystal SiC is a typical material of the third-generation semiconductor, and has wide applications in national defense fields such as military, aerospace, energy, etc., and in people's livelihood fields such as computers, household appliances, digital electronics, etc. Compared with previous semiconductor materials, SiC has advantages such as a large bandgap width, a high breakdown electric field, a large thermal conductivity, a high electron saturation drift rate, and a strong radiation resistance.

[0003] Single crystal SiC has a high hardness and is brittle, and is prone to defects such as cracks and scratches during the processing. Moreover, SiC has a stable chemical property and is difficult to react with other substances, which results in problems such as low processing efficiency and poor processing quality, and greatly limits its large-scale application and development in the field of electronic information manufacturing.

[0004] Chemical mechanical polishing (CMP) is the only effective way to achieve ultra-smooth and damage-free processing of the SiC wafer surface. Among them, the polishing liquid is an important factor affecting the SiC CMP effect. In the existing silicon carbide CMP polishing liquid, most use strong oxidants such as periodate, perchlorate, hypochlorite, and permanganate as the oxidant of the polishing liquid. However, due to its too strong oxidation effect, it usually causes chemical corrosion defects such as orange peel and pits on the surface of the polished SiC wafer, seriously affecting the surface quality of the SiC wafer, and the reduced products such as manganese dioxide adhere to the surface of the equipment and the wafer and are difficult to clean. In contrast, it is more appropriate to use hydrogen peroxide as the oxidant of the silicon carbide CMP polishing liquid. In addition, under the condition of an appropriate catalyst, the oxidation effect of hydrogen peroxide can be significantly improved, which helps to improve the CMP material removal rate of the silicon carbide wafer. Among them, taking potassium permanganate as an example, the existing supporting catalysts include Pt catalyst, Fe catalyst, KMnO4, etc. The final finished product removal rate and roughness of the existing technology can no longer meet the needs of higher precision. Summary of the Invention

[0005] In view of this, the present invention provides a silicon carbide CMP fine polishing liquid and a preparation method thereof. By adopting an efficient catalyst, the present invention can effectively catalyze hydrogen peroxide, significantly improve the oxidation ability of hydrogen peroxide, thereby improving the material removal rate of the polishing liquid and reducing the surface roughness of the polished wafer. At the same time, the raw materials used in the polishing liquid are environmentally friendly, the waste liquid is easy to treat, and there is no damage to the equipment, realizing ultra-smooth and damage-free processing of silicon carbide.

[0006] The technical means adopted by the present invention are as follows:

[0007] A silicon carbide CMP fine polishing liquid, the composition of which includes silicon dioxide abrasive, catalyst, catalyst activator, dispersant, oxidant, pH regulator and deionized water, and the pH is 8.5 to 11.0; the weight percentages of each component are as follows: silicon dioxide abrasive: 5wt.% to 20wt.%, catalyst: 1wt.% to 5wt.%, catalyst activator: 0.1wt.% to 2wt.%, dispersant: 0.1wt.% to 1wt.%, oxidant: 0.5wt.% to 5wt.%, pH regulator: 0.1wt.% to 0.5wt.%, and the rest is deionized water. The pH is preferably 9.5.

[0008] Further, the silicon dioxide abrasive is silicon dioxide particles, and the particle size of the silicon dioxide abrasive is 30 to 100 nanometers.

[0009] Further, the catalyst is vanadate.

[0010] Further, the catalyst is one or a mixture of several of calcium vanadate, ammonium vanadate, sodium metavanadate, tripotassium vanadate, ammonium sodium vanadate, sodium orthovanadate, lithium vanadate, lead vanadate, manganese vanadate. Sodium metavanadate and sodium metavanadate are preferred, and sodium metavanadate is more preferred.

[0011] Further, the catalyst activator is niobium salt.

[0012] Further, the catalyst activator is one or a mixture of several of niobium pentoxide, niobium dioxide, niobium oxalate, sodium niobate, potassium niobate, niobium pentachloride, niobium hydroxide, ammonium oxalate niobate hydrate, niobium bromide, copper niobate, lithium niobate. Niobium pentoxide and niobium hydroxide are preferred for the niobium salt, and niobium hydroxide is more preferred.

[0013] Further, the dispersant is an organic solvent, and the dispersant is specifically one or a mixture of several of ethanol, sodium hexametaphosphate, fructose molecule, cetyltrimethylammonium bromide, citric acid, polyvinylpyrrolidone PVP, ammonium polyacrylate and polyethyleneimine PEI. Cetyltrimethylammonium bromide and polyvinylpyrrolidone PVP are preferred for the dispersant, and polyvinylpyrrolidone PVP is more preferred.

[0014] Further, the oxidant is hydrogen peroxide.

[0015] Further, the pH regulator is one or a mixture of several of hydrochloric acid, phosphoric acid, oxalic acid, sodium hydroxide, ammonia water and potassium hydroxide. Sodium hydroxide and potassium hydroxide are preferred, and potassium hydroxide is more preferred.

[0016] The present invention also discloses a preparation method of the above-mentioned silicon carbide CMP fine polishing liquid, which includes the following steps:

[0017] Step 1, weighing 40 wt.% to 60 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 1 wt.% to 5 wt.% of the catalyst accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a catalyst aqueous solution;

[0018] Step 2, weighing 1 wt.% to 10 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding an appropriate amount of a pH regulator to make the solution alkaline, and then adding 0.1 wt.% to 2 wt.% of a catalyst activator accounting for the total mass fraction of the polishing liquid, stirring evenly to dissolve it, and obtaining a catalyst activator aqueous solution;

[0019] Step 3, weighing deionized water accounting for 1 wt.% to 5 wt.% of the total mass fraction of the polishing liquid, adding a dispersant accounting for 0.1 wt.% to 1 wt.% of the total mass fraction of the polishing liquid, and stirring evenly to obtain a dispersant aqueous solution;

[0020] Step 4, weighing 5 wt.% to 20 wt.% of silica particles accounting for the total mass fraction of the polishing liquid, and uniformly dispersing the silica particles in 10 wt.% to 20 wt.% of deionized water accounting for the total mass fraction of the polishing liquid to obtain a colloidal silica slurry;

[0021] Step 5, fully mixing the catalyst aqueous solution prepared in step 1, the catalyst activator aqueous solution prepared in step 2, and the dispersant aqueous solution prepared in step 3, and stirring evenly to obtain a mixed solution;

[0022] Step 6, slowly adding the colloidal silica slurry prepared in step 4 to the mixed solution prepared in step 5, and stirring sufficiently to obtain a polishing solution;

[0023] Step 7, add 1wt.% to 5wt.% of hydrogen peroxide to the polishing liquid obtained in step 6, stir evenly, add 0.1wt.% to 0.5wt.% of potassium hydroxide to the total mass fraction of the polishing liquid, adjust to the corresponding pH value, and obtain the silicon carbide CMP fine polishing liquid.

[0024] The working principle of the present invention is that hydrogen peroxide generates a large number of hydroxyl radicals (OH·) in the polishing liquid under the combined action of a catalyst and a catalyst activator. The hydroxyl radicals have stronger oxidizing properties and can quickly oxidize the surface of the silicon carbide wafer to generate an oxide layer with lower hardness on the wafer surface. Subsequently, the oxide layer is removed by the mechanical action of the abrasive in the polishing liquid under a certain polishing pressure, thereby achieving a fine polishing effect. The reaction process involved can be expressed as follows: SiC+4OH · →SiO2+CO2+2H2O.

[0025] Compared with the prior art, the present invention has the following advantages: The polishing liquid prepared by the present invention has higher processing efficiency and better surface quality. Its components are simple, easy to prepare, not prone to crystallization and foaming during the polishing process, has no corrosive effect on the machine tool, has good economic benefits, is easy to store, can be recycled, is convenient to clean after use, has good process performance, and is suitable for sub-nanometer polishing of the surface of silicon carbide wafer substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is the surface roughness map of silicon carbide sample 1# in Embodiment 1 of the present invention;

[0028] Figure 2 It is the surface roughness map of silicon carbide sample 2# in Embodiment 2 of the present invention;

[0029] Figure 3 It is the surface roughness map of silicon carbide sample 3# in Embodiment 3 of the present invention;

[0030] Figure 4 It is the surface roughness map of silicon carbide sample 4# in Embodiment 4 of the present invention;

[0031] Figure 5 It is the surface roughness map of silicon carbide sample 5# in Embodiment 5 of the present invention;

[0032] Figure 6 It is the surface roughness map of silicon carbide sample 6# in Comparative Example 1 of the present invention;

[0033] Figure 7 It is the surface roughness map of silicon carbide sample 7# in Comparative Example 2 of the present invention;

[0034] Figure 8 It is the surface roughness map of silicon carbide sample 8# in Comparative Example 3 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The following will refer to the drawings and combine with the embodiments to detail the present invention.

[0036] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. The description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments of the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0038] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods and devices should be regarded as part of the specification. In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0039] The silicon carbide wafer substrate used in the experiment is a 6-inch Si-face silicon carbide wafer substrate.

[0040] The model of the machine tool used in the experiment is a CP-610R2-SVI chemical mechanical polishing equipment, with a polishing fluff damping cloth polishing pad, a polishing disc diameter of 610 mm, a polishing pressure of 3 - 6 psi, a polishing disc rotation speed of 35 - 80 rpm, a pressure plate rotation speed of 35 - 80 rpm, a polishing fluid flow rate of 300 mL / min, a polishing time of 4 hours. The polishing experiment is carried out at room temperature. After polishing, the silicon carbide wafer substrate is first cleaned with an ultrasonic cleaning machine, then dried with dry air, and then weighed on an electronic balance. The removal rate (nm / h) of the silicon carbide wafer substrate is obtained from the weight difference before and after polishing.

[0041] Example 1

[0042] Step 1, weighing 60 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 1 wt.% of sodium orthovanadate accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a catalyst aqueous solution;

[0043] Step 2, weighing deionized water accounting for 10 wt.% of the total mass fraction of the polishing liquid, adding an appropriate amount of pH regulator to make the solution alkaline, and then adding 0.1 wt.% of niobium pentoxide accounting for the total mass fraction of the polishing liquid, stirring evenly to dissolve it, to obtain a catalyst activator aqueous solution;

[0044] Step 3, weighing 5 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 0.1 wt.% of hexadecylmethylammonium bromide accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a dispersant aqueous solution;

[0045] Step 4, weighing silica particles with a particle size of 30 nanometers and accounting for 5 wt.% of the total mass fraction of the polishing liquid, and uniformly dispersing them in deionized water accounting for 20 wt.% of the total mass fraction of the polishing liquid to obtain colloidal silica slurry;

[0046] Step 5, fully mixing the catalyst aqueous solution prepared in step 1, the catalyst activator aqueous solution prepared in step 2, the dispersant aqueous solution prepared in step 3 and the remaining amount of deionized water, and uniformly stirring to obtain a mixed solution;

[0047] Step 6, slowly adding the colloidal silica slurry prepared in step 4 to the mixed solution prepared in step 5, and stirring sufficiently to obtain a polishing solution;

[0048] Step 7, adding 5 wt.% of hydrogen peroxide to the polishing liquid obtained in step 6, stirring evenly, and adjusting the pH value to 8 with potassium hydroxide to obtain the silicon carbide CMP fine polishing liquid of Example 1.

[0049] Example 2

[0050] Step 1, weighing 55 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 3 wt.% of sodium ammonium vanadate accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a catalyst aqueous solution;

[0051] Step 2, weighing 8 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding an appropriate amount of pH regulator to make the solution alkaline, and then adding 0.5 wt.% of niobium hydroxide accounting for the total mass fraction of the polishing liquid, stirring evenly to dissolve it, to obtain a catalyst activator aqueous solution;

[0052] Step 3, weighing 5 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 1 wt.% of polyvinyl pyrrolidone PVP accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a dispersant aqueous solution;

[0053] Step 4, weighing silica particles with a particle size of 50 nanometers and a total mass fraction of 10 wt.% of the polishing liquid, and uniformly dispersing them in deionized water with a total mass fraction of 15 wt.% of the polishing liquid to obtain colloidal silica slurry;

[0054] Step 5, fully mixing the catalyst aqueous solution prepared in step 1, the catalyst activator aqueous solution prepared in step 2, the dispersant aqueous solution prepared in step 3 and the remaining amount of deionized water, and uniformly stirring to obtain a mixed solution;

[0055] Step 6, slowly adding the colloidal silica slurry prepared in step 4 to the mixed solution prepared in step 5, and stirring sufficiently to obtain a polishing solution;

[0056] Step 7, adding 2 wt.% of hydrogen peroxide to the polishing liquid obtained in step 6, stirring evenly, and adjusting the pH value to 9.5 with potassium hydroxide to obtain the silicon carbide CMP fine polishing liquid of Example 2.

[0057] Example 3

[0058] Step 1, weighing 50 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 2 wt.% of tripotassium vanadate accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a catalyst aqueous solution;

[0059] Step 2, weighing 6 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding an appropriate amount of pH regulator to make the solution alkaline, and then adding 0.7 wt.% of niobium dioxide accounting for the total mass fraction of the polishing liquid, stirring evenly to dissolve it, to obtain a catalyst activator aqueous solution;

[0060] Step 3, weighing 2 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 0.3 wt.% of ethanol accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a dispersant aqueous solution;

[0061] Step 4, weighing silica particles with a particle size of 50 nanometers and a total mass fraction of 12 wt.% of the polishing liquid, and uniformly dispersing the silica particles in deionized water with a total mass fraction of 12 wt.% of the polishing liquid to obtain colloidal silica slurry;

[0062] Step 5, fully mixing the catalyst aqueous solution prepared in step 1, the catalyst activator aqueous solution prepared in step 2, the dispersant aqueous solution prepared in step 3 and the remaining amount of deionized water, and uniformly stirring to obtain a mixed solution;

[0063] Step 6, slowly adding the colloidal silica slurry prepared in step 4 to the mixed solution prepared in step 5, and stirring sufficiently to obtain a polishing solution;

[0064] Step 7, add 3 wt.% of hydrogen peroxide to the polishing liquid obtained in step 6, stir evenly, and adjust the pH value to 8.5 with potassium hydroxide to obtain the silicon carbide CMP fine polishing liquid of Example 3.

[0065] Example 4

[0066] Step 1, weighing 45 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 4 wt.% of lithium vanadate accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a catalyst aqueous solution;

[0067] Step 2, weighing 4 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding an appropriate amount of pH regulator to make the solution alkaline, and then adding 1.5 wt.% of niobium bromide accounting for the total mass fraction of the polishing liquid, stirring evenly to dissolve it, to obtain a catalyst activator aqueous solution;

[0068] Step 3, weighing 3 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 0.8 wt.% of citric acid accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a dispersant aqueous solution;

[0069] Step 4, weighing silica particles with a particle size of 70 nanometers and a total mass fraction of 13 wt.% of the polishing liquid, and uniformly dispersing the silica particles in deionized water with a total mass fraction of 16 wt.% of the polishing liquid to obtain colloidal silica slurry;

[0070] Step 5, fully mixing the catalyst aqueous solution prepared in step 1, the catalyst activator aqueous solution prepared in step 2, the dispersant aqueous solution prepared in step 3 and the remaining amount of deionized water, and uniformly stirring to obtain a mixed solution;

[0071] Step 6, slowly adding the colloidal silica slurry prepared in step 4 to the mixed solution prepared in step 5, and stirring sufficiently to obtain a polishing solution;

[0072] Step 7, adding 3.5 wt.% of hydrogen peroxide to the polishing liquid obtained in step 6, stirring evenly, adjusting the pH value to 9.5 with sodium hydroxide, and obtaining the silicon carbide CMP fine polishing liquid of Example 4.

[0073] Example 5

[0074] Step 1, weighing 40 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 5 wt.% of sodium metavanadate accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a catalyst aqueous solution;

[0075] Step 2, weighing 1 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding an appropriate amount of pH regulator to make the solution alkaline, and then adding 0.5 wt.% of niobium hydroxide accounting for the total mass fraction of the polishing liquid, stirring evenly to dissolve it, to obtain a catalyst activator aqueous solution;

[0076] Step 3, weighing 1 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 1 wt.% of polyvinyl pyrrolidone PVP accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a dispersant aqueous solution;

[0077] Step 4, weighing silica particles with a particle size of 100 nanometers and a total mass fraction of 20 wt.% of the polishing liquid, and uniformly dispersing them in deionized water with a mass fraction of 10 wt.% to obtain colloidal silica slurry;

[0078] Step 5, fully mixing the catalyst aqueous solution prepared in step 1, the catalyst activator aqueous solution prepared in step 2, the dispersant aqueous solution prepared in step 3 and the remaining amount of deionized water, and uniformly stirring to obtain a mixed solution;

[0079] Step 6, slowly adding the colloidal silica slurry prepared in step 4 to the mixed solution prepared in step 5, and stirring sufficiently to obtain a polishing solution;

[0080] Step 7, add 5 wt.% of hydrogen peroxide to the polishing liquid obtained in step 6, stir evenly, and adjust the pH value to 9.5 with potassium hydroxide to obtain the silicon carbide CMP fine polishing liquid of Example 5.

[0081] The experimental results of Examples 1-5 are shown in Table 1.

[0082] Serial number Removal rate (nm / h) Roughness (nm) Surface quality Example 1 156 0.15 No obvious scratches Example 2 177 0.12 No obvious scratches Example 3 186 0.11 No obvious scratches Example 4 203 0.09 No obvious scratches Example 5 221 0.08 No obvious scratches

[0083] Table 1

[0084] It can be seen from the above five groups of embodiments that by using the fine polishing liquid and the preparation method thereof proposed in the present invention, the surface quality of the wafer obtained after polishing is good, there are no obvious scratches, and the material removal rate is also high.

[0085] In order to verify the necessity of catalyst, catalyst activator and dispersant for good polishing performance of polishing liquid, the following three groups of comparative examples were implemented.

[0086] Comparative Example 1

[0087] The preparation method used is the same as that of Example 1, except that no catalyst, catalyst activator, or dispersant is added to the polishing liquid;

[0088] Comparative Example 2

[0089] The preparation method adopted is the same as that in Example 1, except that no catalyst activator or dispersant is added to the polishing liquid.

[0090] Comparative Example 3

[0091] The preparation method adopted is the same as that in Example 1, except that no dispersant is added to the polishing liquid.

[0092]

[0093] Table 2

[0094] It can be seen from the above three groups of comparative example experiments that under the same process parameters, the lack of a catalyst will cause hydrogen peroxide to not decompose quickly to generate hydroxyl radicals, which in turn leads to a weakened oxidation effect of the polishing liquid, resulting in a decrease in the removal rate of the polishing material and an increase in scratches on the surface of the polished silicon carbide wafer. After adding the catalyst, the effect is significantly improved. In addition, it can be known by comparison that the addition of a catalyst activator and a dispersant can further improve the polishing effect.

[0095] In summary, the polishing efficiency of the polishing liquid with a catalyst added is much better than that without a catalyst added. In addition, the addition of a catalyst activator can further increase the removal rate, and the appropriate addition of a dispersant can improve the dispersibility of the abrasive, thereby further improving the processing surface quality and not having too much impact on the polishing rate.

[0096] 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; and 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 silicon carbide CMP fine polishing liquid, characterized in that: The ingredients include silicon oxide abrasive, catalyst, catalyst activator, dispersant, oxidant, pH regulator and deionized water, and the pH value is 8.5-11.0; the weight percentage of each component is as follows: silicon oxide abrasive: 5wt.%-20wt.%, catalyst: 1wt.%-5wt.%, catalyst activator: 0.1wt.%-2wt.%, dispersant: 0.1wt.%-1wt.%, oxidant: 0.5wt.%-5wt.%, pH regulator: 0.1wt.%-0.5wt.%, and the rest is deionized water.

2. The silicon carbide CMP fine polishing liquid according to claim 1, characterized in that: The particle size of the silicon oxide abrasive is 30 to 100 nanometers.

3. The silicon carbide CMP fine polishing liquid according to claim 1, characterized in that: The catalyst is vanadate.

4. The silicon carbide CMP fine polishing liquid according to claim 1, characterized in that: The catalyst is one or a mixture of calcium vanadate, ammonium vanadate, sodium metavanadate, tripotassium vanadate, sodium ammonium vanadate, sodium orthovanadate, lithium vanadate, lead vanadate and manganese vanadate.

5. The silicon carbide CMP fine polishing liquid according to claim 1, characterized in that: The catalyst activator is a niobium salt.

6. The silicon carbide CMP fine polishing liquid according to claim 1, characterized in that: The catalyst activator is one or a mixture of niobium pentoxide, niobium dioxide, niobium oxalate, sodium niobate, potassium niobate, niobium pentachloride, niobium hydroxide, ammonium niobate oxalate hydrate, niobium bromide, copper niobate, and lithium niobate.

7. The silicon carbide CMP fine polishing liquid according to claim 1, characterized in that: The dispersant is one or a mixture of ethanol, sodium hexametaphosphate, fructose molecules, hexadecylmethylammonium bromide, citric acid, polyvinylpyrrolidone PVP, ammonium polyacrylate and polyethyleneimine PEI.

8. The silicon carbide CMP fine polishing liquid according to claim 1, characterized in that: The oxidant is hydrogen peroxide.

9. The silicon carbide CMP fine polishing liquid according to claim 1, characterized in that: The pH regulator is one or a mixture of hydrochloric acid, phosphoric acid, oxalic acid, sodium hydroxide, ammonia water and potassium hydroxide.

10. A method for preparing a silicon carbide CMP fine polishing liquid, characterized in that: The steps include: Step 1, weighing 40 wt.% to 60 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding 1 wt.% to 5 wt.% of the catalyst accounting for the total mass fraction of the polishing liquid, and stirring evenly to obtain a catalyst aqueous solution; Step 2, weighing 1 wt.% to 10 wt.% of deionized water accounting for the total mass fraction of the polishing liquid, adding an appropriate amount of a pH regulator to make the solution alkaline, and then adding 0.1 wt.% to 2 wt.% of a catalyst activator accounting for the total mass fraction of the polishing liquid, stirring evenly to dissolve it, and obtaining a catalyst activator aqueous solution; Step 3, weighing deionized water accounting for 1 wt.% to 5 wt.% of the total mass fraction of the polishing liquid, adding a dispersant accounting for 0.1 wt.% to 1 wt.% of the total mass fraction of the polishing liquid, and stirring evenly to obtain a dispersant aqueous solution; Step 4, weighing 5 wt.% to 20 wt.% of silica particles accounting for the total mass fraction of the polishing liquid, and uniformly dispersing the silica particles in 10 wt.% to 20 wt.% of deionized water accounting for the total mass fraction of the polishing liquid to obtain a colloidal silica slurry; Step 5, fully mixing the catalyst aqueous solution prepared in step 1, the catalyst activator aqueous solution prepared in step 2, and the dispersant aqueous solution prepared in step 3, and stirring evenly to obtain a mixed solution; Step 6, slowly adding the colloidal silica slurry prepared in step 4 to the mixed solution prepared in step 5, and stirring sufficiently to obtain a polishing solution; Step 7, add 1wt.% to 5wt.% of hydrogen peroxide to the polishing liquid obtained in step 6, stir evenly, add 0.1wt.% to 0.5wt.% of potassium hydroxide to the total mass fraction of the polishing liquid, adjust to the corresponding pH value, and obtain the silicon carbide CMP fine polishing liquid.

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