Cleaning method of silicon carbide wafer

Abstract

The invention provides a silicon carbide wafer cleaning method which comprises the following steps: (1) carrying out ultrasonic microbubble cleaning on a silicon carbide wafer by using an ozone-containing cleaning solution to obtain a pre-cleaned silicon carbide wafer; (2) cleaning the pre-cleaned silicon carbide wafer by using an acidic cleaning solution to obtain a primarily cleaned silicon carbide wafer; (3) cleaning the primarily cleaned silicon carbide wafer with hydrofluoric acid to obtain a secondarily cleaned silicon carbide wafer; (4) cleaning the secondarily cleaned silicon carbide wafer by using an alkaline cleaning solution to obtain a tertiary cleaned silicon carbide wafer; and (5) cleaning the triple-cleaned silicon carbide wafer by using a second acidic cleaning solution to obtain the cleaned silicon carbide wafer. According to the cleaning method, the residual polishing solution and organic pollutants on the surface of the wafer can be effectively removed, and the cleaning efficiency is improved while the cleaning effect is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors and relates to a method for cleaning a silicon carbide wafer. Background Art

[0002] Silicon carbide (SiC), as one of the most important third-generation semiconductor materials, is widely used in power electronics, radio frequency devices, optoelectronic devices and other fields due to its excellent properties such as large bandgap, high saturated electron mobility, strong breakdown field, and high thermal conductivity. Since SiC wafer processing requires the participation of many organic and inorganic substances, and many processes require human participation, the product will inevitably be contaminated by some organic matter, particles, metals, oxides and other impurities. In the integrated circuit made of silicon carbide, each component and connection is very fine. During the manufacturing process, if it is contaminated by these impurities, it is easy to cause damage to the circuit function in the chip, forming a short circuit or open circuit, causing the integrated circuit to fail and causing serious losses.

[0003] In the silicon carbide industry, wafer cleaning is a key process, the purpose of which is to remove dirt on the wafer surface, such as residual polishing liquid, particles, organic pollutants, metal ions and other impurities, in order to improve the quality and performance of silicon carbide wafers. The traditional cleaning process is mainly RCA tank cleaning, which is not ideal for removing heavy residual polishing liquid, heavy organic pollutants and particle dirt on the wafer surface. In addition, as the production capacity of tank cleaning increases, the distance between wafers becomes smaller and smaller, which further increases the difficulty of wafer cleaning.

[0004] CN118737813A discloses a cleaning method for removing metal impurities on the surface of a silicon carbide wafer, comprising the following steps: sequentially cleaning the silicon carbide wafer to be cleaned with an H2SO4-H2O2 cleaning solution, a first NH4OH-H2O2-H2O cleaning solution, an HCl-H2O2-H2O cleaning solution, an HF-H2O2-H2O cleaning solution, and a second NH4OH-H2O2-H2O cleaning solution, and drying to obtain a cleaned silicon carbide wafer; the concentration of NH4OH in the first NH4OH-H2O2-H2O cleaning solution is 0.5-2wt%, and the concentration of H2O2 is 0.5-2wt%; the concentration of NH4OH in the second NH4OH-H2O2-H2O cleaning solution is 0.5-2wt%, and the concentration of H2O2 is 5-7.5wt%.

[0005] CN114078692A discloses a wafer cleaning method, which includes using a supercritical fluid of carbon dioxide and an aerosol of carbon dioxide to simultaneously flush the surface of the wafer, and then volatilizing the carbon dioxide on the surface of the wafer into a gaseous state, so that organic matter and particulate contaminants are separated from the surface of the wafer during the flushing process, thereby achieving the cleaning of the organic matter and particulate contaminants on the surface of the wafer.

[0006] The wafer cleaning method described in the above scheme takes a long time to process and is not ideal in removing dirt from the wafer surface. Summary of the invention

[0007] The object of the present invention is to provide a method for cleaning silicon carbide wafers. In the cleaning method of the present invention, an ozone-containing cleaning solution is first used to perform ultrasonic micro-nano bubble pre-cleaning treatment on the silicon carbide wafer, while improving the pre-cleaning effect, and then a suitable cleaning agent is used to perform step-by-step cleaning, thereby removing the polishing liquid and heavy organic pollutants remaining on the surface of the silicon carbide wafer to the greatest extent, enhancing the subsequent cleaning effect of the silicon carbide wafer and shortening the wafer cleaning time.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for cleaning a silicon carbide wafer, the cleaning method comprising the following steps:

[0010] (1) using an ozone-containing cleaning solution to perform ultrasonic microbubble cleaning on a silicon carbide wafer to obtain a pre-cleaned silicon carbide wafer;

[0011] (2) performing a first cleaning on the pre-cleaned silicon carbide wafer using a first acidic cleaning solution to obtain a first-cleaned silicon carbide wafer;

[0012] (3) performing a second cleaning on the first-washed silicon carbide wafer using hydrofluoric acid to obtain a second-washed silicon carbide wafer;

[0013] (4) performing a third cleaning on the second-washed silicon carbide wafer using an alkaline cleaning solution to obtain a third-washed silicon carbide wafer;

[0014] (5) Using the second acidic cleaning solution, the triple-cleaned silicon carbide wafer is cleaned for the fourth time to obtain a cleaned silicon carbide wafer.

[0015] The present invention pre-uses an ozone-containing cleaning solution to perform ultrasonic microbubble cleaning on a silicon carbide wafer. Ozone is a molecule with strong oxidizing properties, which can efficiently and thoroughly oxidize and decompose organic matter. At the same time, it can oxidize metal ions into high-valent states through its strong oxidizing properties to form insoluble oxides or hydroxides, thereby removing inorganic pollutants such as metal ions. The degradation rate of ozone is relatively fast, and it will not have an adverse effect on the chip. Micro-nano bubbles have a large specific surface area and surface energy, and can effectively adsorb and wrap pollutants on the surface of the wafer, such as particles, organic matter, metal ions, etc. Through the rise and rupture of the bubbles, the pollutants are brought to the liquid surface, achieving an efficient cleaning effect. The pre-cleaned silicon carbide wafer is first cleaned using a first acidic cleaning solution, which can remove heavy organic contamination and part of the metal on the surface of the silicon carbide wafer. Hydrofluoric acid cleaning can remove the natural oxide film on the surface of the silicon carbide wafer, thereby dissolving the metal attached to the oxide film. Alkaline cleaning solution cleaning can remove particles on the surface of the silicon carbide wafer. The second cleaning solution can remove metal contamination such as sodium, iron, magnesium, etc. on the surface of the silicon carbide wafer.

[0016] Among them, in the cleaning method of the silicon carbide wafer of the present invention, after each cleaning, the wafer needs to be rinsed with ultrapure water and then dried with a low-boiling point organic solvent.

[0017] Preferably, the solute of the ozone-containing cleaning solution in step (1) includes ozone, a polishing cleaning agent and water.

[0018] Preferably, the polishing cleaning agent includes any two or a combination of at least three of sodium hydroxide, hydrogen peroxide, fatty alcohol polyoxyethylene ether or glycerol.

[0019] Preferably, the temperature of the ozone-containing cleaning solution in step (1) is 30°C to 50°C, for example, 30°C, 35°C, 40°C, 45°C or 50°C, etc., and is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0020] Preferably, in the ozone-containing cleaning solution of step (1), the mass concentration of the polishing cleaning agent is 10wt% to 20wt%, for example: 10wt%, 12wt%, 15wt%, 18wt% or 20wt%, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, in the ozone-containing cleaning solution of step (1), the mass concentration of ozone is 0.1 mg / L to 1 mg / L, for example: 0.1 mg / L, 0.2 mg / L, 0.5 mg / L, 0.8 mg / L or 1 mg / L, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the ultrasonic microbubble cleaning in step (1) comprises:

[0023] The ozone-containing cleaning solution is subjected to a foaming treatment to generate micro-nano bubbles in the ozone-containing cleaning solution, and ultrasound is turned on at the same time. Under ultrasonic conditions, the silicon carbide wafer is cleaned using the ozone-containing cleaning solution containing micro-nano bubbles.

[0024] Preferably, the power of the foaming treatment is 0.3kW to 1kW, for example, 0.3kW, 0.5kW, 0.6kW, 0.8kW or 1kW, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] Preferably, the average diameter of the micro-nano bubbles is 0.1 μm to 1 μm, for example, 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm or 1 μm, etc., and is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the time for ultrasonic microbubble cleaning in step (1) is 10 min to 30 min, for example, 10 min, 15 min, 20 min, 25 min or 30 min, etc., not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] Preferably, in step (2), the first acidic cleaning solution comprises sulfuric acid and hydrogen peroxide.

[0028] Preferably, the mass concentration of sulfuric acid in the first acidic cleaning solution in step (2) is 80wt% to 90wt%, for example: 80wt%, 82wt%, 85wt%, 88wt% or 90wt%, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the mass concentration of hydrogen peroxide in the first acidic cleaning solution in step (2) is 10wt% to 20wt%, for example: 10wt%, 12wt%, 15wt%, 18wt% or 20wt%, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the temperature of the first cleaning in step (2) is 100°C to 120°C, for example, 100°C, 105°C, 110°C, 115°C or 120°C, etc., and is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the first cleaning time in step (2) is 15 min to 30 min, for example, 15 min, 18 min, 20 min, 25 min or 30 min, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the concentration of the hydrofluoric acid in step (3) is 5wt% to 10wt%, for example, 5wt%, 6wt%, 8wt%, 9wt% or 10wt%, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] Preferably, the temperature of the second cleaning in step (3) is 20°C to 25°C, for example, 20°C, 21°C, 22°C, 23°C, 24°C or 25°C, etc., and is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the second cleaning time in step (3) is 15 min to 30 min, for example, 15 min, 18 min, 20 min, 25 min or 30 min, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the alkaline cleaning solution in step (4) comprises ammonia water and hydrogen peroxide.

[0036] Preferably, the mass concentration of aqueous ammonia in the alkaline cleaning solution in step (4) is 10wt% to 15wt%, for example: 10wt%, 11wt%, 12wt%, 13wt%, 14wt% or 15wt%, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the mass concentration of hydrogen peroxide in the alkaline cleaning solution in step (4) is 15wt% to 20wt%, for example: 15wt%, 16wt%, 17wt%, 18wt%, 19wt% or 20wt%, etc., not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] Preferably, the temperature of the third cleaning in step (4) is 30°C to 50°C, for example, 30°C, 35°C, 40°C, 45°C or 50°C, etc., and is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, the time for the third cleaning in step (4) is 15 min to 30 min, for example, 15 min, 18 min, 20 min, 25 min or 30 min, etc., not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] Preferably, in step (5), the second acidic cleaning solution comprises hydrochloric acid and hydrogen peroxide.

[0041] Preferably, the mass concentration of hydrochloric acid in the second acidic cleaning solution in step (5) is 15wt% to 20wt%, for example: 15wt%, 16wt%, 17wt%, 18wt%, 19wt% or 20wt%, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, the mass concentration of hydrogen peroxide in the second acidic cleaning solution in step (5) is 15wt% to 20wt%, for example: 15wt%, 16wt%, 17wt%, 18wt%, 19wt% or 20wt%, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] Preferably, the temperature of the fourth cleaning in step (5) is 65°C to 85°C, for example, 65°C, 70°C, 75°C, 80°C or 85°C, etc., and is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, the fourth cleaning time in step (5) is 15 min to 30 min, for example, 15 min, 18 min, 20 min, 25 min or 30 min, etc., not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) In the cleaning method of the silicon carbide wafer described in the present invention, loose polishing liquid and some heavy pollutants on the surface of the wafer can be effectively removed through pre-cleaning, greatly improving the cleaning effect. Subsequently, a suitable cleaning agent is used for step-by-step cleaning to remove the polishing liquid and heavy organic pollutants remaining on the surface of the silicon carbide wafer to the greatest extent, thereby improving the cleaning effect and the cleaning efficiency.

[0047] (2) The method of the present invention consumes little of the various cleaning agents, and the service life of each cleaning agent is prolonged, thereby improving economic benefits and reducing the discharge of waste liquid, thus achieving the purpose of being environmentally friendly. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0049] The polishing cleaning agent used in the examples and comparative examples of the present invention is a mixed solution of sodium hydroxide, fatty alcohol polyoxyethylene ether and glycerol. The micro-nano bubble generating system used is Zhongjing ZJC-NM.

[0050] Example 1

[0051] This embodiment provides a method for cleaning a silicon carbide wafer, the cleaning method comprising the following steps:

[0052] (1) installing a micro-nano bubble generating system inside an ultrasonic cleaning machine, using the micro-nano bubble generating system to perform foaming treatment on an ozone-containing cleaning solution at a power of 0.8 kW to form micro-nano bubbles with an average particle size of 0.5 μm, turning on ultrasound, and performing ultrasonic micro-bubble cleaning on a silicon carbide wafer at 50° C. for 30 minutes to obtain a pre-cleaned silicon carbide wafer, wherein the mass concentration of ozone in the ozone-containing cleaning solution is 0.5 mg / L, and the mass concentration of the polishing cleaning agent is 15 wt %;

[0053] (2) using an acidic cleaning solution having a sulfuric acid mass concentration of 90 wt % and a hydrogen peroxide mass concentration of 10 wt %, cleaning the pre-cleaned silicon carbide wafer at 120° C. for 30 min to obtain a washed silicon carbide wafer;

[0054] (3) using hydrofluoric acid with a concentration of 10 wt % to clean the first-washed silicon carbide wafer at 22° C. for 30 min to obtain a second-washed silicon carbide wafer;

[0055] (4) using an alkaline cleaning solution having an ammonia concentration of 15 wt % and a hydrogen peroxide concentration of 15 wt % to clean the second-washed silicon carbide wafer at 45° C. for 30 min to obtain a third-washed silicon carbide wafer;

[0056] (5) Using an acidic cleaning solution having a hydrochloric acid mass concentration of 15 wt % and a hydrogen peroxide mass concentration of 15 wt %, the triple-washed silicon carbide wafer was cleaned at 85° C. for 30 min to obtain a cleaned silicon carbide wafer.

[0057] Example 2

[0058] This embodiment provides a method for cleaning a silicon carbide wafer, the cleaning method comprising the following steps:

[0059] (1) installing a micro-nano bubble generating system inside an ultrasonic cleaning machine, using the micro-nano bubble generating system to perform foaming treatment on an ozone-containing cleaning solution at a power of 0.5 kW to form micro-nano bubbles with an average particle size of 0.1 μm, turning on ultrasound, and performing ultrasonic micro-bubble cleaning on a silicon carbide wafer at 40° C. for 30 minutes to obtain a pre-cleaned silicon carbide wafer, wherein the mass concentration of ozone in the ozone-containing cleaning solution is 0.6 mg / L, and the mass concentration of the polishing cleaning agent is 15 wt %;

[0060] (2) using an acidic cleaning solution having a sulfuric acid mass concentration of 90 wt % and a hydrogen peroxide mass concentration of 10 wt %, cleaning the pre-cleaned silicon carbide wafer at 120° C. for 30 min to obtain a washed silicon carbide wafer;

[0061] (3) using hydrofluoric acid with a concentration of 10 wt % to clean the first-washed silicon carbide wafer at 20° C. for 30 min to obtain a second-washed silicon carbide wafer;

[0062] (4) using an alkaline cleaning solution having an ammonia concentration of 15 wt % and a hydrogen peroxide concentration of 15 wt % to clean the second-washed silicon carbide wafer at 30° C. for 30 min to obtain a third-washed silicon carbide wafer;

[0063] (5) Using an acidic cleaning solution having a hydrochloric acid mass concentration of 10 wt % and a hydrogen peroxide mass concentration of 10 wt %, the triple-washed silicon carbide wafer was cleaned at 65° C. for 30 minutes to obtain a cleaned silicon carbide wafer.

[0064] Example 3

[0065] This embodiment provides a method for cleaning a silicon carbide wafer, the cleaning method comprising the following steps:

[0066] (1) installing a micro-nano bubble generating system inside an ultrasonic cleaning machine, using the micro-nano bubble generating system to perform foaming treatment on an ozone-containing cleaning solution at a power of 1 kW to form micro-nano bubbles with an average particle size of 1 μm, turning on ultrasound, and performing ultrasonic micro-bubble cleaning on a silicon carbide wafer at 40° C. for 30 minutes to obtain a pre-cleaned silicon carbide wafer, wherein the mass concentration of ozone in the ozone-containing cleaning solution is 0.7 mg / L, and the mass concentration of the polishing cleaning agent is 15 wt %;

[0067] (2) using an acidic cleaning solution having a sulfuric acid mass concentration of 90 wt % and a hydrogen peroxide mass concentration of 10 wt %, cleaning the pre-cleaned silicon carbide wafer at 150° C. for 30 min to obtain a washed silicon carbide wafer;

[0068] (3) using hydrofluoric acid with a concentration of 10 wt % to clean the first-washed silicon carbide wafer at 25° C. for 30 min to obtain a second-washed silicon carbide wafer;

[0069] (4) using an alkaline cleaning solution having an ammonia concentration of 15 wt % and a hydrogen peroxide concentration of 15 wt % to clean the second-washed silicon carbide wafer at 80° C. for 30 min to obtain a third-washed silicon carbide wafer;

[0070] (5) Using an acidic cleaning solution having a hydrochloric acid mass concentration of 15 wt % and a hydrogen peroxide mass concentration of 15 wt %, the triple-washed silicon carbide wafer was cleaned at 85° C. for 30 min to obtain a cleaned silicon carbide wafer.

[0071] Example 4

[0072] The only difference between this embodiment and embodiment 1 is that the power of the micro-nano bubble generating system is 0.1 kW, the average particle size of the ultrasonic nano-micro bubbles is 0.05 μm, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0073] Example 5

[0074] The only difference between this embodiment and embodiment 1 is that the power of the micro-nano bubble generating system is 2 kW, the average particle size of the ultrasonic nano-micro bubbles is 2 μm, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0075] Example 6

[0076] The only difference between this embodiment and embodiment 1 is that the mass concentration of ozone in the ozone-containing cleaning solution is 0.05 mg / L, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0077] Example 7

[0078] The only difference between this embodiment and embodiment 1 is that the mass concentration of ozone in the ozone-containing cleaning solution is 2 mg / L, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0079] Comparative Example 1

[0080] The only difference between this comparative example and Example 1 is that a cleaning solution without ozone is used, and the other conditions and parameters are exactly the same as those in Example 1.

[0081] Comparative Example 2

[0082] The only difference between this comparative example and Example 1 is that no micro-nano bubble generating system is used to perform foaming treatment on the ozone-containing cleaning solution, and only ultrasonic cleaning is performed. Other conditions and parameters are exactly the same as those in Example 1.

[0083] Performance Testing:

[0084] The cleaned silicon carbide wafers obtained in the embodiment and the comparative example were tested, and the particle content on the surface of the silicon carbide wafer (particle size range 0.3 μm to 0.5 μm) was tested by surface defect detection equipment, and the metal impurity content on the surface of the silicon carbide wafer was tested by ICP-MS detection means. The test results are shown in Table 1:

[0085] Table 1

[0086]

[0087]

[0088] As can be seen from Table 1, from Examples 1-7, the cleaning method of the silicon carbide wafer of the present invention has a high cleaning effect on the wafer, and the metal impurity content of the obtained silicon carbide wafer can reach 1.80E10atom / cm 2 Below, the content of particles with a size of 0.3 μm to 0.5 μm on each silicon carbide wafer can reach less than 121.

[0089] By comparing Example 1 with Examples 4-5, it can be seen that in the cleaning method for silicon carbide wafers described in the present invention, the power of the micro-nano bubble generating system will affect the particle size of the generated nano-micro bubbles, and thus affect the cleaning effect of the pre-cleaning. When the power of the micro-nano bubble generating system is controlled at 0.3kW to 1kW, micro-nano bubbles with a particle size of 0.1μm to 1μm can be generated, and the pre-cleaning effect is better. If the power of the micro-nano bubble generating system is too large, the volume of the generated bubbles is too large, and the rising speed in the cleaning solution is too fast, and the cleaning effect is reduced. If the power of the micro-nano bubble generating system is too small, the volume of the generated bubbles is too small, and the internal pressure increases due to the surface tension of the bubbles, causing the gas partial pressure in the bubbles to exceed the dissolved gas partial pressure around the bubbles, which will cause the bubbles to further shrink. The reduction in volume leads to an enhanced surface tension effect, resulting in a positive feedback effect, and the bubbles will collapse rapidly, their lifespan will be shortened, and the cleaning effect will be reduced.

[0090] By comparing Example 1 with Examples 6-7, it can be seen that in the cleaning method for silicon carbide wafers described in the present invention, the mass concentration of ozone in the ozone-containing cleaning solution will affect the cleaning effect of the pre-cleaning. When the mass concentration of ozone is controlled at 0.1 mg / L to 1 mg / L, the pre-cleaning effect is better. If the mass concentration of ozone is too high, the bubble content in the solution is too high, the contact area between the polishing cleaning agent and the wafer is reduced, and the cleaning effect is reduced. If the mass concentration of ozone is too low, the amount of bubbles generated is insufficient, the oxidation and decomposition effect of organic matter is poor, and the cleaning ability is reduced.

[0091] From the comparison between Example 1 and Comparative Example 1, it can be seen that ozone is a molecule with strong oxidizing properties. The cleaning solution containing ozone used in the present invention can efficiently and thoroughly oxidize and decompose organic matter, and can also remove inorganic pollutants such as metal ions. In addition, the degradation rate of ozone is relatively fast and will not have an adverse effect on the chip.

[0092] By comparing Example 1 with Comparative Example 2, it can be seen that the present invention can significantly improve the cleaning effect of removing dirt from the wafer surface through ultrasonic cleaning and micro-nano bubble cleaning.

[0093] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for cleaning a silicon carbide wafer, characterized in that: The cleaning method comprises the following steps: (1) using an ozone-containing cleaning solution to perform ultrasonic microbubble cleaning on a silicon carbide wafer to obtain a pre-cleaned silicon carbide wafer; (2) performing a first cleaning on the pre-cleaned silicon carbide wafer using a first acidic cleaning solution to obtain a first-cleaned silicon carbide wafer; (3) performing a second cleaning on the first-washed silicon carbide wafer using hydrofluoric acid to obtain a second-washed silicon carbide wafer; (4) performing a third cleaning on the second-washed silicon carbide wafer using an alkaline cleaning solution to obtain a third-washed silicon carbide wafer; (5) Using the second acidic cleaning solution, the triple-cleaned silicon carbide wafer is cleaned for the fourth time to obtain a cleaned silicon carbide wafer.

2. The cleaning method according to claim 1, characterized in that The solute of the ozone-containing cleaning solution in step (1) includes ozone, a polishing cleaning agent and water; Preferably, the polishing cleaning agent comprises any two or a combination of at least three of sodium hydroxide, hydrogen peroxide, fatty alcohol polyoxyethylene ether or glycerol; Preferably, the temperature of the ozone-containing cleaning solution in step (1) is 30° C. to 50° C.; Preferably, in the ozone-containing cleaning solution of step (1), the mass concentration of the polishing cleaning agent is 10wt% to 20wt%; Preferably, in the ozone-containing cleaning solution of step (1), the mass concentration of ozone is 0.1 mg / L to 1 mg / L.

3. The cleaning method according to claim 1 or 2, characterized in that: The ultrasonic microbubble cleaning in step (1) comprises: The ozone-containing cleaning solution is subjected to a foaming treatment to generate micro-nano bubbles in the ozone-containing cleaning solution, and ultrasound is turned on at the same time. Under ultrasound conditions, the silicon carbide wafer is cleaned using the ozone-containing cleaning solution containing micro-nano bubbles; Preferably, the power of the foaming treatment is 0.3kW to 1kW; Preferably, the average diameter of the micro-nano bubbles is 0.1 μm to 1 μm; Preferably, the ultrasonic microbubble cleaning time in step (1) is 10 min to 30 min.

4. The cleaning method according to any one of claims 1 to 3, characterized in that: Step (2) the first acidic cleaning solution comprises sulfuric acid and hydrogen peroxide; Preferably, the mass concentration of sulfuric acid in the first acidic cleaning solution in step (2) is 80wt% to 90wt%; Preferably, the mass concentration of hydrogen peroxide in the first acidic cleaning solution in step (2) is 10 wt % to 20 wt %.

5. The cleaning method according to any one of claims 1 to 4, characterized in that: Step (2) The first cleaning temperature is 100°C to 120°C Preferably, the first cleaning time in step (2) is 15 min to 30 min.

6. The cleaning method according to any one of claims 1 to 5, characterized in that: The concentration of the hydrofluoric acid in step (3) is 5wt% to 10wt%; Preferably, the temperature of the second cleaning in step (3) is 20°C to 25°C; Preferably, the second cleaning time in step (3) is 15 min to 30 min.

7. The cleaning method according to any one of claims 1 to 6, characterized in that: The alkaline cleaning solution in step (4) comprises ammonia water and hydrogen peroxide; Preferably, the mass concentration of ammonia water in the alkaline cleaning solution in step (4) is 10wt% to 15wt%; Preferably, the mass concentration of hydrogen peroxide in the alkaline cleaning solution in step (4) is 15wt% to 20wt%.

8. The cleaning method according to any one of claims 1 to 7, characterized in that: The temperature of the third cleaning in step (4) is 30°C to 50°C; Preferably, the third cleaning time in step (4) is 15 min to 30 min.

9. The cleaning method according to any one of claims 1 to 8, characterized in that: Step (5) the second acidic cleaning solution comprises hydrochloric acid and hydrogen peroxide; Preferably, the mass concentration of hydrochloric acid in the second acidic cleaning solution in step (5) is 15wt% to 20wt%; Preferably, the mass concentration of hydrogen peroxide in the second acidic cleaning solution in step (5) is 15wt% to 20wt%.

10. The cleaning method according to any one of claims 1 to 9, characterized in that: The temperature of the fourth cleaning in step (5) is 65°C to 85°C; Preferably, the fourth cleaning time in step (5) is 15 min to 30 min.

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