Cleaning method of silicon carbide wafer after chemical mechanical polishing

Abstract

The invention provides a method for cleaning a silicon carbide wafer after chemical mechanical polishing, which comprises the following steps: A) cleaning the polishing solution on the surface of the silicon carbide wafer based on an Al2O3-KMnO4 system polishing solution by using water, and then carrying out ultrasonic cleaning by using an organic solvent; b) ultrasonically cleaning the silicon carbide wafer by adopting a citric acid-hydrogen peroxide-sulfuric acid solution; c) carrying out a series of cleaning process operations, including QDR cleaning, on the cleaned wafer; the cleaning agent comprises an alkaline solution; and D) drying the cleaned silicon carbide wafer to obtain the silicon carbide wafer. According to the method for cleaning the wafer, dirt of the wafer can be effectively removed, polishing solution residues, particles and scratches are avoided, the cleanliness of the wafer is improved, and the quality of the silicon carbide wafer is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor processing, in particular to a method for cleaning a silicon carbide wafer after chemical mechanical polishing. Background Art

[0002] Silicon carbide has a high Young's modulus, high hardness, high temperature resistance, and corrosion resistance. Regarding the hardness of silicon carbide, the Mohs hardness is 9.5, second only to the world's hardest diamond, which has a Mohs hardness of 10. In order to achieve a good removal rate and flatness for silicon carbide wafers, the current mainstream process technology is chemical mechanical polishing. The wafer is in close contact with the polishing pad, and the abrasive enters between the wafer and the polishing pad along with the polishing liquid. On the one hand, the friction provides heat to maintain and accelerate the chemical reaction (especially at the surface bumps). On the other hand, it gives the abrasive the function to impact, shear and peel off the reaction layer. The peeled reaction layer is carried away by the polishing liquid, exposing a new surface reaction to generate a new reaction layer. The bumps on the wafer surface disappear, and a flat and low-roughness surface is obtained.

[0003] After double-sided rough polishing, wafers may retain polishing slurry residue, necessitating a series of cleaning processes, including QDR cleaning. This removes Al2O3-KMnO4 chemicals, large particles, and impurities from the polishing slurry. Acidic ultrasonic cleaning uses a ratio of citric acid to hydrogen peroxide of 1:10 to 1:25 at a temperature of 20-30°C. This process primarily removes metal oxides and organic contaminants introduced by the polishing slurry. The next step after double-sided rough polishing is single-sided fine polishing. Single-sided polishing only removes 0.5μm of material, requiring high wafer cleanliness. This post-rough polishing cleaning step requires high cleanliness to prevent scratches caused by Al and Mn oxides introduced during the single-sided polishing process.

[0004] Therefore, it is very necessary to provide a method for cleaning silicon carbide wafers after chemical mechanical polishing. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a method for cleaning silicon carbide wafers after chemical mechanical polishing. The cleaning method provided by the present invention can effectively remove dirt from the wafers after cleaning, and there is no polishing liquid residue, particles and scratches, thereby improving the cleanliness of the wafers.

[0006] The present invention provides a method for cleaning a silicon carbide wafer after chemical mechanical polishing, comprising the following steps:

[0007] A) A silicon carbide wafer using an Al2O3-KMnO4 polishing slurry is cleaned with water and then ultrasonically cleaned with an organic solvent.

[0008] B) ultrasonically cleaning the silicon carbide wafer using a citric acid-hydrogen peroxide-sulfuric acid solution;

[0009] C) subjecting the cleaned wafer to a series of cleaning processes, including QDR cleaning; the cleaning agent comprises an alkaline solution;

[0010] D) drying the cleaned silicon carbide wafer.

[0011] Preferably, the water washing time in step A) is 5 to 8 minutes;

[0012] The organic solvent includes ethanol or acetone; the cleaning time is 10 to 13 minutes.

[0013] Preferably, in step B), the volume ratio of citric acid to hydrogen peroxide is 1:10 to 1:40;

[0014] The pH value of the solution is adjusted to 2-5 using sulfuric acid.

[0015] Preferably, the ultrasonic cleaning time in step B) is 10 to 20 minutes; and the ultrasonic power is 40 kHz.

[0016] Preferably, the alkaline solution in step C) is KOH;

[0017] The cleaning agent further comprises a surfactant; the surfactant is tridecyl alcohol ethoxylate.

[0018] Preferably, the amount of the alkaline solution added is 0.5L; the amount of the surfactant added is 0.1L

[0019] Preferably, the QDR cleaning methods in step C) include overflow, bubbling, spraying, gravity discharge and ultrasonic device.

[0020] Preferably, the cleaning time in step C) (excluding deionized water cleaning) is 20 to 40 minutes, the temperature is 50 to 70° C., and the ultrasonic power is 40 kHz to 120 kHz.

[0021] Preferably, in step C), in the overflow, spraying and bubbling processes, the deionized water cleaning process alone lasts for 5 to 15 minutes at room temperature.

[0022] Preferably, the drying in step D) is performed by drying in a spin dryer, and the drying time is 8 to 10 minutes.

[0023] Compared with the prior art, the present invention provides a method for cleaning silicon carbide wafers after chemical mechanical polishing, comprising the following steps: A) using a polishing liquid based on an Al2O3-KMnO4 system on a silicon carbide wafer, cleaning the polishing liquid on the wafer surface with water, and then ultrasonically cleaning with an organic solvent; B) ultrasonically cleaning the silicon carbide wafer with a citric acid-hydrogen peroxide-sulfuric acid solution; C) subjecting the cleaned wafer to a series of cleaning processes, including QDR cleaning; the cleaning agent includes an alkaline solution; and D) drying the cleaned silicon carbide wafer. The present invention's method for cleaning wafers can effectively remove dirt from the wafer, leaving no polishing liquid residue, particles, or scratches, thereby improving the cleanliness of the wafer and ensuring the quality of the silicon carbide wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a picture of the cleanliness of the silicon carbide wafer after cleaning, as displayed on the 88 detection equipment in Example 3;

[0025] Figure 2 This is a photo of the cleaned silicon carbide wafer shown on a microscope at 200 times magnification in Example 3;

[0026] Figure 3 This is a picture of the cleaned silicon carbide wafer shown on a microscope at 100 times magnification in Example 3;

[0027] Figure 4 This is a photo of the cleaned silicon carbide wafer shown on a microscope at 50 times magnification in Example 3. DETAILED DESCRIPTION

[0028] The present invention provides a method for cleaning silicon carbide wafers after chemical mechanical polishing. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve the desired results. It should be noted that all similar substitutions and modifications are obvious to those skilled in the art and fall within the scope of protection of the present invention. The methods and applications of the present invention have been described through preferred embodiments. It is obvious that relevant personnel can modify or appropriately change and combine the methods and applications herein without departing from the content, spirit, and scope of the present invention to implement and apply the technology of the present invention.

[0029] In this application, the term "and / or" describes the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0030] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items.

[0031] Extensive experiments have shown that wafers left for several hours after rough polishing are significantly more difficult to clean than those cleaned immediately. Large shards of polishing solution residue and metal particles can be observed under a darkroom or microscope. Rough polished wafers should be cleaned as quickly as possible. For example, an ultrasonic cleaning system can accommodate 3-4 wafer boxes simultaneously, while a cleaning tank can accommodate 2. This achieves cleanliness standards while also improving production efficiency.

[0032] The present invention provides a method for cleaning a silicon carbide wafer after chemical mechanical polishing, comprising the following steps:

[0033] A) A silicon carbide wafer using an Al2O3-KMnO4 polishing slurry is cleaned with water and then ultrasonically cleaned with an organic solvent.

[0034] B) ultrasonically cleaning the silicon carbide wafer using a citric acid-hydrogen peroxide-sulfuric acid solution;

[0035] C) subjecting the cleaned wafer to a series of cleaning processes, including QDR cleaning; the cleaning agent comprises an alkaline solution;

[0036] D) drying the cleaned silicon carbide wafer.

[0037] The Al2O3-KMnO4 system polishing liquid provided by the present invention for silicon carbide wafers is well known to those skilled in the art and is not limited thereto.

[0038] For silicon carbide wafers using an Al2O3-KMnO4 polishing solution, water is used to clean the polishing solution on the wafer surface. The water rinse time is 5 to 8 minutes.

[0039] Then, ultrasonic cleaning is performed using an organic solvent, wherein the organic solvent includes ethanol or acetone; the cleaning time is 10 to 15 minutes, more preferably 10 to 13 minutes, and most preferably 10 minutes.

[0040] Using organic solvents such as ethanol or acetone can dissolve and remove oil and organic contaminants from the wafer surface. Organic contaminants (e.g., grease, organic colloids, etc.) on the wafer surface can be quickly dissolved by ethanol, causing them to fall off the surface. Furthermore, ethanol reduces the surface tension of the liquid, forming a uniform liquid film on the wafer surface, effectively removing tiny particles and contaminants attached to the surface.

[0041] The silicon carbide wafer was ultrasonically cleaned using a citric acid-hydrogen peroxide-sulfuric acid solution.

[0042] According to the present invention, the volume ratio of citric acid to hydrogen peroxide is 1:10 to 1:40;

[0043] In some embodiments, the volume ratio of citric acid to hydrogen peroxide is 1:10, 1:20, 1:30, 1:40, or any value in between.

[0044] The present invention uses sulfuric acid to adjust the pH value of the solution to 2-5; specifically, it can be 2, 3, 4 or 5; or a point value between any two of the above.

[0045] The ultrasonic cleaning time of the present invention is 10 to 20 minutes; the ultrasonic power is 40KHZ.

[0046] The inventors have creatively discovered that the above-mentioned cleaning agent can remove metal oxides and organic pollutants introduced by the polishing liquid. The carboxyl group in the citric acid molecule forms a coordination bond with the oxide or hydroxyl group in the metal ion. This coordination bond can change the charge distribution in the metal ion, thereby changing the properties and reactivity of the metal oxide. In an acidic solution, the metal oxide can undergo a complex reaction with citric acid and be removed. In addition, citric acid is a tricarboxylic acid and has reducing properties. Citric acid can undergo an oxidation-reduction reaction with potassium permanganate to generate CO2 and H2O, thereby fading potassium permanganate. Hydrogen peroxide has oxidizing properties under acidic conditions and can convert silicon carbide into a silicon dioxide layer. The reaction formula involved is as follows: H2O2+2H + +SiC+2e - →SiO2+2H2O.

[0047] Furthermore, hydrogen peroxide decomposes under acidic conditions to generate hydroxyl radicals (·OH). ·OH radicals can efficiently oxidize and decompose organic matter, metal ions, and other pollutants remaining on the silicon carbide surface, converting them into soluble low-molecular compounds. These low-molecular compounds are dissolved and removed in the solution, thereby achieving a clean surface for the silicon carbide wafer.

[0048] Sulfuric acid, as a strong acid, is highly corrosive and oxidizing. It reacts with organic or inorganic impurities on the surface, which may be residual organic or inorganic matter from the silicon carbide wafer production process. Sulfuric acid oxidizes these impurities into gases or water-soluble substances, thereby removing them. Sulfuric acid can remove the metallic oxide layer formed during the silicon carbide wafer production process, leaving the wafer surface cleaner.

[0049] The above three synergistic effects lead to better removal of the wafer surface of the present invention.

[0050] The wafer that has been ultrasonically cleaned is then cleaned.

[0051] The cleaning agent of the present invention comprises an alkaline solution. The alkaline solution is KOH, and the amount of the alkaline solution added is 0.5L;

[0052] The cleaning agent of the present invention further comprises a surfactant; the surfactant is tridecyl alcohol ethoxylate. Preferably, the amount of the surfactant added is 0.1L

[0053] According to the present invention, the cleaning methods include overflow, bubbling, spraying, gravity discharge, and ultrasonic devices. The above methods are well known to those skilled in the art and are not limited thereto.

[0054] A series of cleaning process operations, including QDR cleaning, are carried out to remove the residual citric acid solution and obtain a clean silicon carbide wafer. The cleaning agent used is KOH. In the alkaline solution, the SiO2 layer is removed by reaction, and organic matter and particles are also removed as the SiO2 layer peels off. The reaction formula involved is as follows: SiO2+2OH - →[SiO3] 2- +H2O.

[0055] The cleaning time of the present invention (excluding deionized water cleaning) is 20 to 40 minutes, the temperature is 50 to 70° C., and the ultrasonic power is 40 kHz to 120 kHz.

[0056] Specifically, in the overflow, spraying and bubbling processes, the deionized water cleaning process alone takes 5 to 15 minutes at room temperature.

[0057] The cleaned silicon carbide wafer is dried to obtain the obtained product. The drying is carried out by a spin dryer, and the drying time is 8 to 10 minutes.

[0058] The present invention provides a method for cleaning silicon carbide wafers after chemical mechanical polishing, comprising the following steps: A) using a polishing liquid based on an Al2O3-KMnO4 system on a silicon carbide wafer, cleaning the polishing liquid on the wafer surface with water, and then ultrasonically cleaning with an organic solvent; B) ultrasonically cleaning the silicon carbide wafer with a citric acid-hydrogen peroxide-sulfuric acid solution; C) subjecting the cleaned wafer to a series of cleaning processes, including QDR cleaning; the cleaning agent includes an alkaline solution; and D) drying the cleaned silicon carbide wafer. The method for cleaning the wafer of the present invention can effectively remove dirt from the wafer, eliminating polishing liquid residue, particles, and scratches, thereby improving the cleanliness of the wafer and ensuring the quality of the silicon carbide wafer.

[0059] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0060] The numerical ranges and parameters used in this disclosure are presented as precisely as possible to represent the relevant numerical values ​​of the specific embodiments. However, any numerical value inherently and inevitably contains standard deviations resulting from individual testing methods. Therefore, unless otherwise expressly stated, it should be understood that all numerical ranges or specific data used in this disclosure are subject to reasonable deviation within a certain range, for example, within 1% or 0.5%.

[0061] Some cases are described in the embodiments and comparative examples of the present invention, wherein the embodiments illustrate certain implementations of the present invention. However, this does not mean that the effects of the present invention can only be achieved in these cases.

[0062] To further illustrate the present invention, the method for cleaning a silicon carbide wafer after chemical mechanical polishing provided by the present invention is described in detail below with reference to examples.

[0063] Example 1

[0064] A method for cleaning a wafer after rough polishing, comprising the following steps:

[0065] Step 1: Rinse the silicon carbide wafer using a polishing solution based on the Al2O3-KMnO4 system with clean water for 5 minutes to remove the polishing solution from the wafer surface.

[0066] Step 2: Use common organic solvents such as ethanol or acetone to perform ultrasonic cleaning for 13 minutes to dissolve and remove oil and organic contamination on the surface of the wafer;

[0067] Step 3: Use a citric acid-hydrogen peroxide-sulfuric acid solution to clean the silicon carbide wafer in an ultrasonic environment to remove metal oxides and organic contaminants introduced by the polishing solution. The volume ratio of citric acid to hydrogen peroxide is 1:40, the ultrasonic duration is 10 minutes, the temperature is 25°C, and the ultrasonic device is 40KHZ. Sulfuric acid is added to adjust the solution's pH to approximately 5.

[0068] Step 4: Perform a series of cleaning process operations, including QDR cleaning, to clean the residual citric acid solution and obtain a cleaned silicon carbide wafer. Among them, the cleaning agents are KOH and surfactant tridecyl alcohol ethoxylate, with the addition amounts of 0.5L and 0.1L respectively. The cleaning time is 20 minutes, the temperature is 50°C, and 40KHZ ultrasonic ultrasonic assisted cleaning. The overflow + spray + bubbling process is adopted, and the deionized water cleaning time is 5 minutes at room temperature;

[0069] Step 5: Place the silicon carbide wafers symmetrically into the spin dryer and spin dry at a high speed for 8 minutes to obtain dry wafers.

[0070] Example 2

[0071] A method for cleaning a wafer after rough polishing, comprising the following steps:

[0072] Step 1: Rinse the silicon carbide wafer using a polishing slurry based on the Al2O3-KMnO4 system with clean water for 5 minutes to remove the polishing slurry from the wafer surface.

[0073] Step 2: Use common organic solvents such as ethanol or acetone to perform ultrasonic cleaning for 10 minutes to dissolve and remove oil and organic contamination on the surface of the wafer;

[0074] Step 3: Use a citric acid-hydrogen peroxide-sulfuric acid solution to clean the silicon carbide wafer in an ultrasonic bath to remove metal oxides and organic contaminants introduced by the polishing solution. The volume ratio of citric acid to hydrogen peroxide is 1:30, the ultrasonic bath is performed for 15 minutes at a temperature of 25°C, and the ultrasonic device is set at 40kHz. Sulfuric acid is added to adjust the solution's pH to approximately 4.

[0075] Step 4: Perform a series of cleaning process operations, including QDR cleaning, to clean the residual citric acid solution and obtain a cleaned silicon carbide wafer. Among them, the cleaning agents are KOH and surfactant tridecyl alcohol ethoxylate, and the addition amounts are 0.5L and 0.1L respectively. The cleaning time is 25 minutes, the temperature is 60°C, and the ultrasonic cleaning is assisted by 40KHZ. The overflow + spray + bubbling process is adopted, and the deionized water cleaning time is 10 minutes at room temperature;

[0076] Step 5: Place the silicon carbide wafers symmetrically into the spin dryer and spin dry at a high speed for 8 minutes to obtain dry wafers.

[0077] Example 3

[0078] A method for cleaning a wafer after rough polishing, comprising the following steps:

[0079] Step 1: Rinse the silicon carbide wafer using a polishing slurry based on the Al2O3-KMnO4 system with clean water for 8 minutes to remove the polishing slurry from the wafer surface.

[0080] Step 2: Use common organic solvents such as ethanol or acetone to perform ultrasonic cleaning for 10 minutes to dissolve and remove oil and organic contamination on the surface of the wafer;

[0081] Step 3: Use a citric acid-hydrogen peroxide-sulfuric acid solution to clean the silicon carbide wafer in an ultrasonic environment to remove metal oxides and organic contaminants introduced by the polishing solution. The volume ratio of citric acid to hydrogen peroxide is 1:20, the ultrasonic duration is 15 minutes, the temperature is 30°C, and the ultrasonic device is 40KHZ. Sulfuric acid is added to adjust the pH of the solution to around 3;

[0082] Step 4: Perform a series of cleaning process operations, including QDR cleaning, to clean the residual citric acid solution and obtain a cleaned silicon carbide wafer. Among them, the cleaning agents are KOH and surfactant tridecyl alcohol ethoxylate, and the addition amounts are 0.5L and 0.1L respectively. The cleaning time is 30 minutes, the temperature is 65°C, and the ultrasonic cleaning is assisted by 80KHZ. The overflow + spray + bubbling process is adopted, and the deionized water cleaning time is 10 minutes at room temperature;

[0083] Step 5: Place the silicon carbide wafers symmetrically into the spin dryer and spin dry at a high speed for 8 minutes to obtain dry wafers.

[0084] Example 4

[0085] A method for cleaning a wafer after rough polishing, comprising the following steps:

[0086] Step 1: Rinse the silicon carbide wafer using a polishing slurry based on the Al2O3-KMnO4 system with clean water for 8 minutes to remove the polishing slurry from the wafer surface.

[0087] Step 2: Use common organic solvents such as ethanol or acetone to perform ultrasonic cleaning for 10 minutes to dissolve and remove oil and organic contamination on the surface of the wafer;

[0088] Step 3: Use a citric acid-hydrogen peroxide-sulfuric acid solution to clean the silicon carbide wafer in an ultrasonic environment to remove metal oxides and organic contaminants introduced by the polishing solution. The volume ratio of citric acid to hydrogen peroxide is 1:10, the ultrasonic time is 20 minutes, the temperature is 30°C, and the ultrasonic device is set to 40kHz. Sulfuric acid is added to adjust the solution's pH to approximately 2.

[0089] Step 4: Perform a series of cleaning process operations, including QDR cleaning, to clean the residual citric acid solution and obtain a cleaned silicon carbide wafer. The cleaning agents are KOH and surfactant tridecyl alcohol ethoxylate, with the addition amounts of 0.5L and 0.1L respectively. The cleaning time is 40 minutes, the temperature is 70°C, and 120KHZ ultrasonic ultrasonic assisted cleaning is used. The overflow + spray + bubbling process is used, and the deionized water cleaning time is 15 minutes at room temperature;

[0090] Step 5: Place the silicon carbide wafers symmetrically into the spin dryer and spin dry at a high speed for 8 minutes to obtain dry wafers.

[0091] Example 5

[0092] Compared with Example 1, other important parameters such as the cleaning time, the organic solvent ultrasonic cleaning time, the dosage ratio of the cleaning agent KOH and the surfactant tridecyl alcohol ethoxylate, and the pH value of sulfuric acid were not changed. Only the ratio of citric acid and hydrogen peroxide was changed for comparison. The volume ratio of citric acid and hydrogen peroxide was changed from 1:40 to 1:25. Under the halogen lamp, it can be seen that when the volume ratio is 1:40, a large area of ​​white mist polishing liquid residue appears, and the area of ​​the polishing liquid residue is about 1 / 3 of the chip area; when the volume ratio is 1:25, there is no large area of ​​white mist polishing liquid residue, only local white mist polishing liquid residue, and the area of ​​the polishing liquid residue is less than 1 / 6 of the chip area. This shows that the volume ratio of citric acid and hydrogen peroxide has an impact on the cleanliness of the chip after cleaning.

[0093] Example 6

[0094] Compared to Example 3, the alkaline cleaning agent cleaning time was shortened from 30 minutes to 20 minutes. Under a halogen lamp, it was observed that after 20 minutes of cleaning with the cleaning agent, no polishing liquid residue remained on the wafer surface. This indicates that the cleaning agent can clean the wafer completely in 20 minutes, eliminating the need for longer cleaning times, and effectively improving cleaning efficiency.

[0095] Comparative Example 1

[0096] Compared to Example 3, only the pH of the sulfuric acid was changed; other cleaning process operations and parameters remained unchanged. The pH of the sulfuric acid was adjusted from 3 to 5. Under a halogen lamp, it was observed that when the pH of the sulfuric acid was 3, no polishing liquid residue remained; at a pH of 5, granular polishing liquid residue appeared on the wafer surface. This indicates that the pH of the sulfuric acid affects the quality of the cleaned wafers.

[0097] Figure 1 This is a picture of the cleanliness of the silicon carbide wafer after cleaning, as shown on the 88 detection equipment in Example 3. Figure 2 、 Figure 3 and Figure 4 The following are pictures of the cleaned silicon carbide wafers magnified 200 times, 100 times and 50 times on a microscope, respectively, for Example 3. Figure 1 It can be seen that the wafer has no scratches, no large particles, and the total number of particles with a particle size of 0.3 to 20 μm is 1. Figure 2 、 Figure 3 and Figure 4 It can be seen that there are no visible particles and scratches under the microscope at three magnifications.

[0098] The cleanliness of the wafers after cleaning in Example 1 and Comparative Example 1 was tested using 88 testing equipment and a microscope. The results are shown in Table 1.

[0099] Table 1

[0100]

[0101] As can be seen from the data in Table 1, Examples 3 and 6 have almost no defect problems, but the total time used in Example 3 is longer, which reduces production efficiency. Through comparison of examples, it can be seen that the wafer can be cleaned more cleanly only under certain organic solvent ultrasonic duration, adjustment of the pH value of sulfuric acid, volume ratio of citric acid and hydrogen peroxide, cleaning time and temperature conditions. The method for cleaning the wafer of the present invention can effectively remove wafer dirt, without polishing liquid residue, particles and scratches, thereby improving the cleanliness of the wafer and ensuring the quality of the silicon carbide wafer.

[0102] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for cleaning a silicon carbide wafer after chemical mechanical polishing, characterized in that: The steps include: A) A silicon carbide wafer using an Al2O3-KMnO4 polishing slurry is cleaned with water and then ultrasonically cleaned with an organic solvent. B) ultrasonically cleaning the silicon carbide wafer using a citric acid-hydrogen peroxide-sulfuric acid solution; C) subjecting the cleaned wafer to a series of cleaning processes, including QDR cleaning; the cleaning agent comprises an alkaline solution; D) drying the cleaned silicon carbide wafer.

2. The cleaning method according to claim 1, wherein The water washing time in step A) is 5 to 8 minutes; The organic solvent includes ethanol or acetone; the cleaning time is 10 to 15 minutes.

3. The cleaning method according to claim 1, wherein Step B) the volume ratio of citric acid to hydrogen peroxide is 1:10 to 1:40; The pH value of the solution is adjusted to 2-5 using sulfuric acid.

4. The cleaning method according to claim 1, wherein The ultrasonic cleaning time in step B) is 10 to 20 minutes; the ultrasonic power is 40KHZ.

5. The cleaning method according to claim 1, wherein Step C) the alkaline solution is KOH; The cleaning agent further comprises a surfactant; the surfactant is tridecyl alcohol ethoxylate.

6. The cleaning method according to claim 5, characterized in that: The amount of the alkaline solution added is 0.5 L; the amount of the surfactant added is 0.1 L.

7. The cleaning method according to claim 1, wherein Step C) The QDR cleaning methods include overflow, bubbling, spraying, gravity discharge and ultrasonic device.

8. The cleaning method according to claim 7, wherein: Step C) The cleaning time is 20 to 40 minutes, the temperature is 50 to 70° C., and the ultrasonic power is 40 kHz to 120 kHz.

9. The cleaning method according to claim 7, wherein: In step C), in the overflow, spraying and bubbling processes, the deionized water cleaning process alone takes 5 to 15 minutes at room temperature.

10. The cleaning method according to claim 1, wherein The drying in step D) is carried out by using a spin dryer, and the drying time is 8 to 10 minutes.

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