A method of cleaning silicon carbide wafers

Abstract

The application relates to the field of semiconductor manufacturing, and discloses a method for cleaning a silicon carbide wafer. The method comprises the following steps: (1) performing first cleaning on the silicon carbide wafer by using an ozone solution to obtain a silicon carbide wafer I; (2) performing second cleaning by using a two-fluid to obtain a silicon carbide wafer II; (3) performing third cleaning by using an ammonia solution to obtain a silicon carbide wafer III; (4) performing fourth cleaning by using a hydrofluoric acid solution to obtain a silicon carbide wafer IV; (5) repeatedly performing the operations in the steps (1) to (4) on the silicon carbide wafer IV in sequence; and (6) performing passivation treatment by using the ozone solution. The method provided by the application can effectively remove surface particles and metal contaminants of the silicon carbide wafer and provide an effective area of the silicon carbide wafer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor manufacturing, in particular to a method for cleaning silicon carbide wafer. BACKGROUND

[0002] As the third generation semiconductor material, silicon carbide has the advantages of wide band gap, high thermal conductivity, high critical breakdown field, high electron saturation drift rate, etc., so it has great application prospects in the field of semiconductor manufacturing.

[0003] At present, the silicon carbide wafer in the industry generally adopts the RCA cleaning method of silicon wafer, and the specific cleaning method is as follows: the silicon carbide wafer is sequentially cleaned according to the order of SPM, DHF, SC-1 and SC-2 to obtain the cleaned silicon carbide wafer, and the specific process is as follows:

[0004] SPM: sulfuric acid (concentration of 98wt%) and hydrogen peroxide (concentration of 30wt%) are prepared into a cleaning solution according to a volume ratio of 4:1, and cleaning is carried out at a temperature of 120-150℃;

[0005] DHF: hydrofluoric acid and H2O are prepared into a cleaning solution according to a volume ratio of 1:100-250, and cleaning is carried out at a temperature of 20-25℃;

[0006] SC-1: ammonia, hydrogen peroxide and H2O are prepared into a cleaning solution according to a volume ratio of 1:1:5, and cleaning is carried out at a temperature of 70℃ for 10min;

[0007] SC-2: hydrochloric acid, hydrogen peroxide and H2O are prepared into a cleaning solution according to a volume ratio of 1:1:5, and cleaning is carried out at a temperature of 70℃ for 10min.

[0008] The RCA cleaning method basically meets the requirements of most wafer cleanliness and can passivate the wafer surface.

[0009] However, using this method to clean the polished silicon carbide wafer will result in unclean silicon carbide wafer, unclean surface particles and metal contamination, and low effective area of the wafer.

[0010] At the same time, hydrogen peroxide has strong irritability to the human body, which is not conducive to the health of the cleaning operators.

[0011] Therefore, a cleaning method is needed which does not use hydrogen peroxide and is suitable for silicon carbide wafers, effectively removes surface particles and metal contaminants of silicon carbide wafers, and also improves the effective area of silicon carbide wafers. SUMMARY

[0012] The present application aims to overcome the problems of the prior art, i.e. the need to use irritating hydrogen peroxide in the cleaning of silicon carbide wafers, and the incomplete removal of surface particles and metal contaminants from silicon carbide wafers, and the low effective area of silicon carbide wafers.

[0013] To achieve the above-mentioned object, the present application provides a method for cleaning silicon carbide wafers, which comprises:

[0014] (1) first cleaning a silicon carbide wafer using an ozone solution, wherein the concentration of ozone in the ozone solution is 25-60 mg / kg, to obtain a silicon carbide wafer I;

[0015] (2) second cleaning the silicon carbide wafer I using a two-fluid, wherein the two-fluid contains nitrogen and water in a volume ratio of 1:30-70, to obtain a silicon carbide wafer II;

[0016] (3) third cleaning the silicon carbide wafer II using an ammonia solution, to obtain a silicon carbide wafer III;

[0017] (4) fourth cleaning the silicon carbide wafer III using a hydrofluoric acid solution, to obtain a silicon carbide wafer IV;

[0018] (5) repeating the operations in steps (1) to (4) in sequence for the silicon carbide wafer IV until the metal ions on the surface of the obtained silicon carbide wafer are ≤10×10 10 atom / cm 2 , the average diameter of the particulate matter is ≤0.3 μm, the surface particle size of the particulate matter with an average diameter of ≤0.3 μm is ≤100, and the average diameter of the particulate matter is ≥0.2 μm, the surface particle size of the particulate matter with an average diameter of ≥0.2 μm is ≤800;

[0019] (6) passivating the silicon carbide wafer obtained after the last cleaning in step (5) using the ozone solution.

[0020] Preferably, the method of the present application further comprises, in step (1), preparing the ozone solution by the following steps:

[0021] S1. electrolyzing a mixed gas containing 89-95 vol% oxygen and 5-11 vol% carbon dioxide at a voltage of 220-380 V to obtain ozone;

[0022] S2. mixing the ozone with ultrapure water at a pressure of 1.5-2.0 MPa to obtain the ozone solution, wherein the volume ratio of the ozone to the ultrapure water is 1:70-80.

[0023] Preferably, in step (3), the concentration of the ammonia solution is 4.5-7 wt%.

[0024] Preferably, in step (4), the concentration of the hydrofluoric acid solution is 2-6wt%.

[0025] Preferably, in step (1), the first cleaning is carried out under stirring, and at least the following conditions are met: temperature is 20-25℃, rotation speed is 500-1500rpm, and cleaning time is 0.5-2min.

[0026] Preferably, in step (2), the second cleaning is carried out in a way of spraying, and at least the following conditions of spraying are met: flow rate is 40-100L / min, temperature is 20-25℃, and cleaning time is 0.2-1.5min.

[0027] Preferably, in step (3), the third cleaning is carried out under stirring, and at least the following conditions are met: temperature is 45-65℃, rotation speed is 750-1500rpm, and cleaning time is 0.5-2min.

[0028] Preferably, in step (4), the fourth cleaning is carried out under stirring, and at least the following conditions are met: temperature is 20-25℃, rotation speed is 750-1500rpm, and cleaning time is 0.2-1.5min.

[0029] Preferably, the method of the present application further comprises: carrying out ultrapure water cleaning on the silicon carbide wafer I, the silicon carbide wafer II and the silicon carbide wafer III to be used for carrying out the second cleaning, the third cleaning and the fourth cleaning, respectively; and

[0030] In step (5), the silicon carbide wafer IV obtained in step (4) is subjected to the ultrapure water cleaning and then used for carrying out again the first cleaning in step (1).

[0031] Preferably, the time of the ultrapure water cleaning is independently 30-60s.

[0032] The method of the present application can effectively remove the organic contaminants, inorganic contaminants, metal contaminants and other strongly adsorbed substances from the silicon carbide wafer without using the irritating hydrogen peroxide, and can improve the effective area of the silicon carbide wafer.

[0033] The method of the present application does not destroy the internal structure of the silicon carbide, only reacts with the surface of the silicon carbide wafer, and exposes the fresh and clean silicon carbide layer by removing the reaction layer on the surface, and the reaction of the solution used for cleaning with the surface of the silicon carbide is slow and controllable. DETAILED DESCRIPTION

[0034] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the invention. Any numeric range recited is intended to include all values from the lower value to the upper value, inclusive of both values, and to also include any value approximately or about the same as that particular value. Numeric ranges can be combined with other numeric ranges to form new numeric ranges, which are to be construed in accordance with the above definition.

[0035] As previously described, the present invention provides a method for cleaning a silicon carbide wafer, the method comprising:

[0036] (1) performing a first cleaning of a silicon carbide wafer using an ozone solution, wherein the ozone solution has a concentration of ozone of 25-60 mg / kg, to obtain a silicon carbide wafer I;

[0037] (2) performing a second cleaning of the silicon carbide wafer I using a two-fluid, wherein the two-fluid comprises nitrogen and water in a volume ratio of 1:30-70, to obtain a silicon carbide wafer II;

[0038] (3) performing a third cleaning of the silicon carbide wafer II using an ammonia solution, to obtain a silicon carbide wafer III;

[0039] (4) performing a fourth cleaning of the silicon carbide wafer III using a hydrofluoric acid solution, to obtain a silicon carbide wafer IV;

[0040] (5) repeating the operations in steps (1) to (4) sequentially on the silicon carbide wafer IV until the surface of the silicon carbide wafer has a metal ion concentration of <10 x 10 10 atom / cm 2 , a surface granularity of <100 for particles having an average diameter of <0.3 μm, and a surface granularity of <800 for particles having an average diameter of >0.2 μm;

[0041] (6) performing a passivation treatment on the silicon carbide wafer obtained after the last cleaning in step (5) using the ozone solution.

[0042] Preferably, in step (6), the passivation treatment is performed under the same conditions as the first cleaning.

[0043] It should be noted that in the present invention, there is no specific requirement for the instrument used to detect the surface granularity, and a conventional instrument in the art can be used, for example, a Candela CS920 surface defect detector or a Candela CS8520 surface defect detector.

[0044] Preferably, the method of the present invention further comprises, in step (1), preparing the ozone solution using the following steps:

[0045] S1, electrolyzing a mixed gas containing 89-95 vol% oxygen and 5-11 vol% carbon dioxide at a voltage of 220-380 V to obtain ozone;

[0046] S2, mixing the ozone with ultrapure water at a pressure of 1.5-2.0 MPa to obtain the ozone solution, wherein the ozone and the ultrapure water are used in a volume ratio of 1:70-80.

[0047] Preferably, in step (3), the concentration of the ammonia solution is 4.5-7 wt%.

[0048] More preferably, in step (3), the concentration of the ammonia solution is 5-6 wt%.

[0049] It should be noted that, in the present application, the ammonia solution can be obtained commercially or prepared by conventional technical means in the art, and an exemplary method for preparing the ammonia solution is provided below, comprising:

[0050] mixing ultrapure water and ammonia water with a concentration of 25-30 wt% at a ratio of 4-5:1 by mass to obtain an ammonia solution with a concentration of 5-6 wt%, wherein the rotation speed is 1000-1250 rpm and the time is 1-3 min.

[0051] Preferably, in step (4), the concentration of the hydrofluoric acid solution is 2-6 wt%.

[0052] It should be noted that, in the present application, the hydrofluoric acid solution can be obtained commercially or prepared by conventional technical means in the art, and an exemplary method for preparing the hydrofluoric acid solution is provided below, comprising:

[0053] mixing ultrapure water and hydrofluoric acid with a concentration of 45-49 wt% at a ratio of 8-11:1 by mass to obtain a hydrofluoric acid solution with a concentration of 2-6 wt% at room temperature, wherein the rotation speed is 1000-1250 rpm and the time is 1-3 min.

[0054] It should be noted that the room temperature is 20±5℃.

[0055] Preferably, in step (1), the first cleaning is carried out under stirring, and at least the following conditions are met: the temperature is 20-25℃, the rotation speed is 500-1500 rpm, and the cleaning time is 0.5-2 min.

[0056] Preferably, in step (2), the second cleaning is performed by spraying, and the spraying at least satisfies: a flow rate of 40-100 L / min, a temperature of 20-25℃, and a cleaning time of 0.2-1.5 min.

[0057] More preferably, the spraying is performed by using a two-fluid spray gun.

[0058] Preferably, in step (3), the third cleaning is performed under stirring, and at least satisfies: a temperature of 45-65℃, a rotation speed of 750-1500 rpm, and a cleaning time of 0.5-2 min.

[0059] Preferably, in step (4), the fourth cleaning is performed under stirring, and at least satisfies: a temperature of 20-25℃, a rotation speed of 750-1500 rpm, and a cleaning time of 0.2-1.5 min.

[0060] According to a preferred embodiment, the method of the present application further comprises: performing an ultrapure water cleaning on the silicon carbide wafer I, the silicon carbide wafer II and the silicon carbide wafer III to be used for performing the second cleaning, the third cleaning and the fourth cleaning, respectively; and

[0061] In step (5), the silicon carbide wafer IV obtained in step (4) is subjected to the ultrapure water cleaning and then used for performing the first cleaning again in step (1).

[0062] Preferably, the ultrapure water cleaning is performed for 30-60 s.

[0063] It should be noted that, in the present application, the means for performing the ultrapure water cleaning is not specifically required, and can be performed by using conventional technical means in the art, such as ultrasonic cleaning or spraying cleaning.

[0064] Preferably, the method of the present application further comprises: reversing the operation sequence of step (3) and step (4), i.e. the silicon carbide wafer II to be used for performing the third cleaning in step (3) is first subjected to the fourth cleaning in step (4) by using the hydrofluoric acid solution to obtain a fourth cleaned silicon carbide wafer, and then the fourth cleaned silicon carbide wafer is subjected to the third cleaning in step (3) by using the ammonia solution to obtain the silicon carbide wafer IV, and the repeated operation in step (5) is also performed according to the operation sequence.

[0065] The present application will be described in detail by way of examples. In the following examples, the raw materials used are all commercially available and are UP-grade industrial raw materials, unless otherwise specified.

[0066] In the following examples, the mass ratio is the total mass of the solution, powder or solid of the substance, unless otherwise specified.

[0067] The part materials used in the following examples and their sources are as follows:

[0068] Silicon carbide wafer: 6-inch silicon carbide, purchased from CREE;

[0069] Surface particle size detection, crystal surface effective area detection, and particle accumulation detection instrument: Candela CS920 surface defect detector, purchased from Kelei Semiconductor Equipment Technology (Shanghai) Co., Ltd.

[0070] Metal ion detection instrument: model HD-TFe, purchased from Horiba.

[0071] Preparation of ammonia water solution:

[0072] At 55℃, ultrapure water and ammonia water with a concentration of 30wt% were mixed at a ratio of 4:1 by mass, to obtain an ammonia water solution with a concentration of 6wt%, wherein the rotation speed was 1100rpm and the time was 2min.

[0073] Preparation of hydrofluoric acid solution:

[0074] At 25℃, ultrapure water and hydrofluoric acid with a concentration of 49wt% were mixed at a ratio of 10:1 by mass, to obtain a hydrofluoric acid solution with a concentration of 4.5wt%, wherein the rotation speed was 1000-1250rpm and the time was 2min.

[0075] Preparation of ozone solution:

[0076] S1, electrolysis of a mixed gas containing 89vol% oxygen and 11vol% carbon dioxide was carried out at a voltage of 380V to obtain ozone;

[0077] S2, the ozone was mixed with ultrapure water at a pressure of 2.0MPa to obtain the ozone solution, wherein the ozone and the ultrapure water were used in a volume ratio of 1:71, to obtain an ozone solution with a concentration of 33mg / L.

[0078] Example 1

[0079] This example is used to illustrate a preferred method for cleaning a silicon carbide wafer provided by the present application, and the specific operation steps are as follows:

[0080] (1) The silicon carbide wafer was first cleaned using the ozone solution under stirring at 22℃ for 1min to obtain a silicon carbide wafer I, wherein the rotation speed was 1000rpm.

[0081] (2) The silicon carbide wafer I was sprayed with ultrapure water for 40 seconds, and then the silicon carbide wafer I that had been cleaned with ultrapure water was cleaned with two fluids for 1 minute at 25°C to obtain silicon carbide wafer II. The two fluids contained nitrogen and water in a volume ratio of 1:40.

[0082] The second cleaning was performed using a two-fluid spray gun with a flow rate of 60 L / min.

[0083] (3) Use ultrapure water to spray clean the silicon carbide wafer II for 40s, and then use ammonia solution to clean the ultrapure water-cleaned silicon carbide wafer II for a third time for 1min under stirring at 55℃ to obtain silicon carbide wafer III, wherein the rotation speed is 1000rpm.

[0084] (4) The silicon carbide wafer III was sprayed with ultrapure water for 40 seconds, and then the silicon carbide wafer III washed with ultrapure water was washed with hydrofluoric acid solution for 1 minute under stirring conditions at 25°C to obtain silicon carbide wafer IV. The rotation speed was 1000 rpm.

[0085] (5) Use ultrapure water to spray clean the silicon carbide wafer IV for 30 seconds, and then repeat the operations in steps (1) to (4) twice on the silicon carbide wafer IV cleaned with ultrapure water.

[0086] (6) Under stirring conditions at 22°C, the silicon carbide wafer obtained after the last cleaning in step (5) is passivated for 1 minute using the ozone solution at a speed of 1000 rpm.

[0087] The clean silicon carbide wafer finally obtained in step (6) is named P1.

[0088] Example 2

[0089] This embodiment uses a similar method to Embodiment 1, except that the cleaning conditions are changed. The specific operation steps are as follows:

[0090] (1) Under stirring conditions at 24°C, the silicon carbide wafer was first cleaned with ozone solution for 1.5 min to obtain silicon carbide wafer I, wherein the rotation speed was 1250 rpm;

[0091] (2) Use ultrapure water to spray clean silicon carbide wafer I for 50s, and then use two fluids at 20°C to clean the silicon carbide wafer I cleaned with ultrapure water for 1.5min to obtain silicon carbide wafer II. The two fluids contain nitrogen and water in a volume ratio of 1:60.

[0092] The second cleaning was performed using a two-fluid spray gun with a flow rate of 80 L / min.

[0093] (3) The silicon carbide wafer II was sprayed with ultrapure water for 50 seconds, and then the silicon carbide wafer II washed with ultrapure water was washed with ammonia solution for 1.2 minutes under stirring conditions at 55°C to obtain silicon carbide wafer III. The rotation speed was 1250 rpm.

[0094] (4) The silicon carbide wafer III was sprayed with ultrapure water for 50 seconds, and then the silicon carbide wafer III washed with ultrapure water was washed with hydrofluoric acid solution for 1.2 minutes under stirring conditions at 20°C to obtain silicon carbide wafer IV. The rotation speed was 1250 rpm.

[0095] (5) Use ultrapure water to spray clean the silicon carbide wafer IV for 50 seconds, and then repeat the operations in steps (1) to (4) three times on the silicon carbide wafer IV cleaned with ultrapure water.

[0096] (6) Under stirring conditions at 24°C, the silicon carbide wafer obtained after the last cleaning in step (5) is passivated for 1.5 min using the ozone solution at a rotation speed of 1250 rpm.

[0097] The clean silicon carbide wafer finally obtained in step (6) is named P2.

[0098] Comparative Example 1

[0099] This comparative example uses the traditional RCA cleaning method for silicon wafers, cleaning the silicon carbide crystals sequentially in the order of SPM, DHF, SC-1, and SC-2. The specific operation steps are as follows:

[0100] SPM: A cleaning solution was prepared by mixing sulfuric acid (98 wt%) and hydrogen peroxide (30 wt%) in a volume ratio of 4:1, and the silicon carbide crystal was cleaned for 5 min under stirring at 120°C.

[0101] DHF: Hydrofluoric acid (concentration of 49wt%) and H2O were prepared into a cleaning solution at a volume ratio of 1:120, and the silicon carbide crystals cleaned in step SPM were cleaned at 25°C for 3 min.

[0102] SC-1: A cleaning solution was prepared by mixing ammonia (29wt%), hydrogen peroxide (30wt%) and H2O in a volume ratio of 1:1:5. The silicon carbide crystals cleaned in step DHF were then cleaned at 70°C for 10 min.

[0103] SC-2: Prepare a cleaning solution by mixing hydrochloric acid (31wt%), hydrogen peroxide (30wt%) and H2O in a volume ratio of 1:1:5, and clean the silicon carbide crystals cleaned in step SC-1 at 70℃ for 10 min.

[0104] The silicon carbide wafer obtained after RCA cleaning in step SC-2 is named DP1.

[0105] Comparative Example 2

[0106] This comparative example was conducted using a method similar to that of Example 1, except that the second cleaning step (2) was not performed. The specific operation steps are as follows:

[0107] SS1. Under stirring conditions at 22°C, the silicon carbide wafer is first cleaned with ozone solution for 1 minute to obtain silicon carbide wafer I, wherein the rotation speed is 1000 rpm;

[0108] SS2. Spray clean the silicon carbide wafer I with ultrapure water for 40 seconds, and then use ammonia solution to clean the ultrapure water-cleaned silicon carbide wafer I for 1 minute under stirring at 55°C to obtain silicon carbide wafer III. The rotation speed is 1000 rpm.

[0109] SS3. The silicon carbide wafer III was sprayed with ultrapure water for 40 seconds. Then, under stirring conditions at 25°C, the silicon carbide wafer III washed with ultrapure water was washed with hydrofluoric acid solution for a fourth cleaning for 1 minute to obtain silicon carbide wafer IV. The rotation speed was 1000 rpm.

[0110] SS4. Use ultrapure water to spray clean the silicon carbide wafer IV for 30 seconds, and then repeat the operations in steps SS1 to SS3 twice on the silicon carbide wafer IV cleaned with ultrapure water.

[0111] SS5. Under stirring conditions at 22°C, the silicon carbide wafer obtained after the last cleaning in step SS4 is passivated with the ozone solution for 1 minute at a rotation speed of 1000 rpm.

[0112] The clean silicon carbide wafer obtained in step SS5 is named DP2.

[0113] Test Example 1

[0114] The effective surface area, particle packing, metal ions, and surface particle size of the cleaned silicon carbide wafers obtained in the above examples were tested, and the results are shown in Table 1.

[0115] Table 1

[0116]

[0117] Note: @ represents the average diameter of particles on the surface of the silicon carbide wafer.

[0118] The results above show that the method provided by this invention can effectively remove organic contaminants, inorganic contaminants, metallic contaminants and other strongly adsorbing substances from silicon carbide wafers without using irritating hydrogen peroxide, while also increasing the effective area of ​​silicon carbide wafers, and is more effective than the traditional RCA cleaning method.

[0119] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method of cleaning a silicon carbide wafer, comprising: The method comprises: (1) performing first cleaning on the silicon carbide wafer using an ozone solution, to obtain a silicon carbide wafer I, wherein the concentration of ozone in the ozone solution is 25-60 mg / kg; (2) performing second cleaning on the silicon carbide wafer I using a two-fluid, to obtain a silicon carbide wafer II, wherein the two-fluid contains nitrogen and water in a volume ratio of 1:30-70; (3) performing third cleaning on the silicon carbide wafer II using an ammonia solution, to obtain a silicon carbide wafer III; (4) performing fourth cleaning on the silicon carbide wafer III using a hydrofluoric acid solution, to obtain a silicon carbide wafer IV; (5) repeating the operations in steps (1) to (4) on the silicon carbide wafer IV until the surface of the resulting silicon carbide wafer has a metal ion concentration of ≤ 10 x 10 10 atoms / cm 2 , and a surface granularity of ≤ 100 for particles having an average diameter of ≤ 0.3 μm and a surface granularity of ≤ 800 for particles having an average diameter of ≥ 0.2 μm. (5) repeating the operations in steps (1) to (4) on the silicon carbide wafer IV until the surface of the resulting silicon carbide wafer has a metal ion concentration of ≤ 10 x 10 10 atoms / cm 2 , and a surface granularity of ≤ 100 for particles having an average diameter of ≤ 0.3 μm and a surface granularity of ≤ 800 for particles having an average diameter of ≥ 0.2 μm. (6) performing passivation treatment on the silicon carbide wafer obtained after the last cleaning in step (5) using the ozone solution.

2. The method of claim 1, wherein, The method further comprises, in step (1), preparing the ozone solution by adopting the following steps: S1. electrolyzing a mixed gas containing 89-95 vol% oxygen and 5-11 vol% carbon dioxide at a voltage of 220-380 V, to obtain ozone; S2. mixing the ozone with ultrapure water at a pressure of 1.5-2.0 MPa, to obtain the ozone solution, wherein the volume ratio of the ozone to the ultrapure water is 1:70-80.

3. The method according to claim 1 or 2, characterized in that, In step (3), the concentration of the ammonia solution is 4.5-7 wt%.

4. The method according to any one of claims 1 to 3, characterized in that, In step (4), the concentration of the hydrofluoric acid solution is 2-6 wt%.

5. The method according to any one of claims 1 to 4, characterized in that, In step (1), the first cleaning is performed under stirring, and at least the following conditions are met: the temperature is 20-25℃, the rotation speed is 500-1500 rpm, and the cleaning time is 0.5-2 min.

6. The method according to any one of claims 1 to 5, characterized in that, In step (2), the second cleaning is performed in a spray cleaning manner, and the spray cleaning at least meets the following conditions: the flow rate is 40-100 L / min, the temperature is 20-25℃, and the cleaning time is 0.2-1.5 min.

7. The method according to any one of claims 1 to 6, characterized in that, In step (3), the third cleaning is performed under stirring, and at least the following conditions are met: the temperature is 45-65℃, the rotation speed is 750-1500 rpm, and the cleaning time is 0.5-2 min.

8. The method according to any one of claims 1 to 7, characterized in that, In step (4), the fourth cleaning is performed under stirring, and at least the following conditions are met: the temperature is 20-25℃, the rotation speed is 750-1500 rpm, and the cleaning time is 0.2-1.5 min.

9. The method according to any one of claims 1 to 8, characterized in that, The method further comprises: performing ultrapure water cleaning on the silicon carbide wafer I, the silicon carbide wafer II, and the silicon carbide wafer III to be applied to perform the second cleaning, the third cleaning, and the fourth cleaning, respectively; and In step (5), the silicon carbide wafer IV obtained in step (4) is subjected to the ultrapure water cleaning and then applied to perform the first cleaning again in step (1).

10. The method of claim 9, wherein, The time of the ultrapure water cleaning is independently 30-60 s.

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