Wafer cleaning method and apparatus

Abstract

The embodiment of the present application provides a wafer cleaning method and device, the wafer has a wafer front surface and a wafer bevel adjacent to the wafer front surface, the method comprises the following steps: keeping the wafer rotating, cleaning the wafer bevel by using an impurity cleaning solution until the wafer bevel is cleaned completely, spraying an oxidizing solution to the wafer front surface until an oxide film generated by the reaction between the oxidizing solution and the wafer covers the wafer front surface completely, and spraying a film-removing cleaning solution to the wafer front surface to remove the oxide film on the wafer front surface.The wafer cleaning method and device can clean the wafer completely.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically, to a wafer cleaning method and apparatus. Background Technology

[0002] In semiconductor manufacturing, several processes can contaminate wafers. For example, chemical-mechanical planarization (CMP), an essential planarization process, generates extremely high levels of contamination, including slurry particles, pad and workpiece debris, carrier abrasive materials, and environmental particles.

[0003] Because wafers are brittle, if significant stress is applied to the right-angled area where the wafer's front and end faces meet during wafer fabrication, it can cause fragmentation, like broken stones, damaging the wafer's front side. Therefore, in existing technologies, the right-angled area is typically chamfered to create a beveled edge, which helps release stress and makes it less likely to cause destructive chipping during wafer fabrication.

[0004] In the process of fabricating chips from wafers, since wafers are circular and chips are square, the beveled edges of the wafer are typically not used for chip fabrication, so contamination on the beveled edges does not interfere with chip manufacturing. However, contamination on the beveled edges can transfer to the front side of the wafer during subsequent manufacturing processes, leading to problems such as uneven doping or short circuits in the manufactured chips. This affects the electrical characteristics of the semiconductor, such as carrier mobility and threshold voltage, ultimately impacting overall performance and reliability. Therefore, improving the cleanliness of the wafer beveled edges is crucial. Summary of the Invention

[0005] The embodiments of this application provide a wafer cleaning method and apparatus that can improve the cleanliness of wafer edges.

[0006] This application provides a wafer cleaning method. The wafer has a front side and a bevel adjacent to the front side. The method includes: keeping the wafer rotated; cleaning the bevel with an impurity cleaning solution until the bevel is clean; spraying an oxide solution onto the front side of the wafer until the oxide film generated by the reaction of the oxide solution with the wafer completely covers the front side of the wafer; and spraying a film removal cleaning solution onto the front side of the wafer to remove the oxide film.

[0007] Specifically, the impurity cleaning solution is dripped onto the beveled edge cleaning brush, and the beveled edge of the wafer is cleaned by the beveled edge cleaning brush.

[0008] Specifically, during the process of spraying the oxide solution onto the front side of the wafer, the wafer is kept rotating at a first rotation speed, and the oxide solution is sprayed until the oxide film completely covers the front side and the bevel of the wafer, wherein the first rotation speed is less than a first critical rotation speed that causes the oxide solution to leave the wafer along the front side.

[0009] Specifically, during the process of spraying the film removal cleaning solution onto the front side of the wafer, the wafer is kept rotating at a second rotation speed, and the film removal cleaning solution is sprayed until the oxide film on the front side and the bevel of the wafer is completely removed. The second rotation speed is less than the second critical rotation speed that causes the film removal cleaning solution to leave the wafer along the front side.

[0010] Specifically, the method further includes spraying deionized water onto the bevel of the wafer to remove impurities from the bevel before spraying the oxide solution onto the front side of the wafer.

[0011] Specifically, the method further includes spraying the film removal cleaning solution onto the front side of the wafer, and then spraying the film removal cleaning solution onto the bevel of the wafer to remove the oxide film on the bevel of the wafer.

[0012] Specifically, during the process of spraying the film removal cleaning solution onto the bevel of the wafer, the wafer is kept rotating at a third rotational speed, which is less than the third critical rotational speed at which the film removal cleaning solution leaves the wafer along the bevel.

[0013] Specifically, after the oxide solution is sprayed onto the front side of the wafer, and before the stripping cleaning solution is sprayed onto the front side of the wafer, the wafer is transferred from the current cleaning chamber to the stripping cleaning chamber.

[0014] Specifically, after the wafer is transferred to the stripping cleaning chamber, and before the stripping cleaning solution is sprayed onto the front side of the wafer, the oxide solution is sprayed onto the front side of the wafer again.

[0015] Specifically, after spraying the film removal cleaning solution onto the front side of the wafer, the steps of spraying the oxide solution and spraying the film removal cleaning solution are repeated in the film removal cleaning chamber until the wafer is cleaned.

[0016] Specifically, the method further includes, after the wafer is cleaned, passing nitrogen gas through the wafer to dry it.

[0017] Specifically, after the wafer is cleaned and before nitrogen gas is introduced into the wafer, an oxide liquid is sprayed onto the front side of the wafer until the oxide film formed by the reaction of the oxide liquid with the wafer completely covers the wafer.

[0018] In another aspect, this application provides a wafer cleaning apparatus, wherein the wafer has a front side and a bevel adjacent to the front side, the apparatus comprising: a rotation unit for rotating the wafer; a bevel cleaning unit for cleaning the bevel with an impurity cleaning solution; a first nozzle for spraying an oxide solution onto the front side of the wafer; a second nozzle for spraying a film-removing cleaning solution onto the front side of the wafer; a controller configured to control the bevel cleaning unit to clean the bevel until the bevel is clean; control the first nozzle to spray the oxide solution onto the front side of the wafer until the oxide film generated by the reaction of the oxide solution with the wafer completely covers the front side of the wafer; and control the second nozzle to spray the film-removing cleaning solution onto the front side of the wafer to remove the oxide film on the front side of the wafer.

[0019] Specifically, the bevel cleaning unit includes a third nozzle and a bevel cleaning brush. The third nozzle is used to drop the impurity cleaning liquid onto the bevel cleaning brush, and the bevel cleaning brush is used to clean the bevel of the wafer.

[0020] The wafer cleaning method and apparatus of this application can effectively clean the wafer bevels by using an impurity cleaning solution to clean them thoroughly. Furthermore, since the wafer bevels are cleaned before the oxide solution is sprayed onto the front side of the wafer, it can prevent metal and other impurities on the wafer bevels from reacting with the oxide solution and becoming difficult to remove.

[0021] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0022] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0024] Figure 1 A schematic diagram of a wafer cleaning apparatus according to an embodiment of this application is shown;

[0025] Figure 2 A schematic flowchart of a wafer cleaning method according to an embodiment of this application is shown. Detailed Implementation

[0026] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0027] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0028] This application provides a wafer cleaning apparatus for improving the cleanliness of wafer bevels.

[0029] like Figure 1As shown, the wafer cleaning apparatus includes a cleaning chamber 1 and a chuck 2 disposed within the cleaning chamber 1. The chuck 2 is rotated by a rotating unit and is used to support and rotate the wafer 3. The rotational speed of the chuck 2 is adjustable, allowing the rotational speed of the wafer 3 to be changed. A movable beveled cleaning brush 4 is disposed in the cleaning chamber 1. During wafer rotation, the beveled cleaning brush 4 is moved to a position contacting the beveled edge 31 of the wafer to clean the beveled edge 31. After cleaning the beveled edge 31, the beveled cleaning brush 4 is removed from the beveled edge 31 to avoid interfering with subsequent steps. The beveled edge 31 is a slope disposed between the front face 32 and the end face 33 of the wafer. The cleaning chamber 1 is also equipped with a nozzle assembly 5, which includes a first nozzle 51 for spraying an oxide solution onto the front side 32 of the wafer and a second nozzle 52 for spraying a film-removing cleaning solution onto the front side 32 of the wafer. The front side 32 of the wafer is cleaned by successively spraying the oxide solution and the film-removing cleaning solution onto it. The nozzle assembly 5 also includes a third nozzle 53 for spraying an impurity cleaning solution onto the beveled edge cleaning brush 4, so that the beveled edge 31 of the wafer is cleaned more thoroughly. A collection tray is also provided below the beveled edge cleaning brush 4 where it contacts the beveled edge 31 of the wafer to minimize the dripping of impurity cleaning solution into the cleaning chamber 1 and causing contamination. The beveled edge cleaning brush 4, the third nozzle 53, and the collection tray constitute the beveled edge cleaning unit. In some embodiments, the first nozzle 51 and the second nozzle 52 are the same nozzle. In some embodiments, the cleaning chamber 1 is also equipped with a movable front-side cleaning brush for brushing the front side 32 of the wafer. In some embodiments, there are two cleaning chambers 1 and two first nozzles 51. One first nozzle 51, the bevel cleaning brush 4, the front cleaning brush, and the third nozzle 53 are in the same cleaning chamber, while the other first nozzle 51 and the second nozzle 52 are in another cleaning chamber. Both cleaning chambers are equipped with chucks 2. The wafer cleaning apparatus also includes a controller configured to clean the beveled edge 31 of the wafer through the bevel cleaning unit until the beveled edge 31 of the wafer is cleaned, spray an oxide solution onto the front side of the wafer 3 through the first nozzle 51 until the oxide film generated by the reaction of the oxide solution with the wafer 3 completely covers the front side 32 of the wafer, and spray a film removal cleaning solution onto the front side 32 of the wafer through the second nozzle to remove the oxide film on the front side 32 of the wafer.

[0030] like Figure 2 As shown, this application also provides a wafer cleaning method, which specifically includes the following steps:

[0031] S110: Keep the wafer rotating horizontally around its center.

[0032] In other embodiments, the rotation center of the wafer is set at a designated location on the wafer other than the center of the circle.

[0033] S120: Drop hydrofluoric acid (HF) solution onto the bevel cleaning brush and clean the bevel of the wafer with the bevel cleaning brush until the bevel of the wafer is clean.

[0034] Hydrofluoric acid solution can remove impurities such as metals adhering to the beveled edges of a wafer. The friction generated by the beveled cleaning brush in contact with the beveled edge further removes impurities from the beveled edge. The hydrofluoric acid solution has a mass concentration of 0.1%-2% dilute hydrofluoric acid. Applying the hydrofluoric acid solution dropwise onto the beveled cleaning brush, compared to applying it directly to the beveled edge, reduces diffusion of the hydrofluoric acid solution on the wafer's front side, improving safety and accuracy. To further reduce diffusion, the amount of hydrofluoric acid solution is sufficient to wet the beveled cleaning brush. Furthermore, since the beveled cleaning brush is typically made of a material with some elasticity, such as nylon, it can also contact the wafer end face when in contact with the bevel, thereby cleaning the wafer end face. In some embodiments, the hydrofluoric acid solution can be replaced with other impurity cleaning solutions capable of reacting with impurities such as metals.

[0035] In some embodiments, to prevent particles on the wafer's front side from being flung to the wafer's bevel during rotation, the wafer's front side is rinsed with deionized water (DIW) before step S120. Deionized water also dilutes the hydrofluoric acid solution that has diffused onto the wafer's front side, reducing the amount of hydrofluoric acid affecting it. In other embodiments, deionized water can be replaced with other cleaning solutions that do not react with subsequent processing solutions.

[0036] S130: The wafer is rotated at a first rotation speed and an oxide solution is sprayed onto the front side of the wafer until an oxide film is formed that completely covers the front side and the bevel of the wafer, wherein the first rotation speed is less than the first critical rotation speed that causes the oxide solution to leave the wafer along the front side.

[0037] On one hand, the oxidizing solution can react with some impurities on the front side of the wafer to remove some of them. On the other hand, the oxidizing solution can react with silicon in the wafer to form a silicon dioxide film. This silicon dioxide film covers the front side of the wafer, which can isolate impurities on the wafer from the front side and encapsulate the isolated impurities, thereby facilitating impurity removal in subsequent steps. In some embodiments, the oxidizing solution includes a mixture of ammonium hydroxide, hydrogen peroxide, and water (SC1). In other embodiments, the oxidizing solution includes ozone water (DIO3) or other oxidizing solutions.

[0038] Step S120 is performed before step S130, that is, before spraying the oxide solution onto the front side of the wafer, metal and other impurities on the wafer bevel are removed. This can prevent metal and other impurities from reacting with the oxide solution and prevent the formation of impurities that are difficult to remove on the wafer bevel.

[0039] Since the wafer rotates at a first rotational speed, which is less than the first critical rotational speed that allows the oxide solution to leave the wafer from the plane containing the front side, the oxide solution can flow down the wafer's bevel, thus forming an oxide film on the bevel. In some embodiments, the first critical rotational speed is determined experimentally. Specifically, the experiment is conducted under the same conditions as in step S130, and the rotational speed at which the oxide solution just flows down the wafer's bevel is taken as the first critical rotational speed. If the wafer rotational speed is higher than the first critical rotational speed, the oxide solution will leave the wafer along the horizontal plane containing the front side, and since the bevel is a chamfer bent downwards from the plane containing the front side, an oxide film cannot form on the bevel. In other embodiments, the first critical rotational speed is calculated based on the frictional force and centrifugal force experienced by the oxide solution on the wafer.

[0040] In some embodiments, in order to form a clean oxide film on the front side of the wafer, while performing step S130, the front side of the wafer is brushed with a front cleaning brush to remove some of the impurities isolated by the oxide film.

[0041] In some embodiments, between steps S120 and S130, deionized water is used to rinse the wafer bevels to remove the hydrofluoric acid solution located on them. In other embodiments, the deionized water is replaced with other cleaning solutions that do not react with the wafer and subsequent processing solutions.

[0042] S140: The wafer is rotated at a second rotation speed and a hydrofluoric acid solution is sprayed onto the front side of the wafer. The second rotation speed is less than the second critical rotation speed that causes the hydrofluoric acid solution to leave the wafer along the front side.

[0043] Because hydrofluoric acid solution can chemically react with the oxide film to form a salt solution, the hydrofluoric acid solution can expose impurities encased in the oxide film to the salt solution. During wafer rotation, the impurities leave the wafer along with the salt solution. In some embodiments, the hydrofluoric acid solution in step S140 is replaced with other film removal cleaning solutions capable of removing the oxide film on the front side of the wafer.

[0044] Spraying hydrofluoric acid solution onto the front side of a wafer rotating at a second rotational speed allows the solution to flow down the wafer's bevel, removing impurities coated with oxide film from the bevel. In some embodiments, the second critical rotational speed is determined experimentally. Specifically, the experiment is conducted under the same conditions as in step S140, and the rotational speed at which the hydrofluoric acid solution just leaves the wafer along the plane of the front side is taken as the second critical rotational speed. If the wafer rotational speed is higher than the second critical rotational speed, the hydrofluoric acid solution will leave the wafer along the horizontal plane, and since the wafer bevel is typically a chamfer bent downwards from the wafer's plane, the bevel cannot be thoroughly cleaned. Of course, the second rotational speed cannot be lower than the critical speed that causes wafer over-etching, to avoid the hydrofluoric acid solution remaining on the front side of the wafer for too long and preventing over-etching. In other embodiments, the second critical rotational speed is calculated based on the frictional force and centrifugal force experienced by the hydrofluoric acid solution on the wafer.

[0045] In some embodiments, to reduce the concentration difference of the hydrofluoric acid solution falling on the front side of the wafer in step S140, deionized water is sprayed onto the front side of the wafer between steps S130 and S140. In other embodiments, the deionized water is replaced with other cleaning solutions that do not react with the wafer and subsequent processing solutions.

[0046] In some embodiments, between steps S130 and S140, an oxide solution is sprayed onto the front side of the wafer again, followed by a hydrofluoric acid solution, to further remove impurities from the front side of the wafer. Furthermore, the steps of spraying the oxide solution and hydrofluoric acid solution again are repeated multiple times to better remove impurities from the wafer. In some embodiments, after the steps of spraying the oxide solution and hydrofluoric acid solution again, deionized water is sprayed onto the front side of the wafer again, and when repeating the steps of spraying the oxide solution and hydrofluoric acid solution, the step of spraying deionized water is performed each time to make the wafer cleaner.

[0047] S150: Spray deionized water onto the front side of the wafer to clean it.

[0048] Spraying deionized water onto the front side of a wafer covered with hydrofluoric acid solution can remove the hydrofluoric acid solution from the front side of the wafer, thereby preventing the hydrofluoric acid solution from remaining on the front side of the wafer for too long and causing over-etching.

[0049] In some embodiments, to thoroughly clean the wafer end face and prevent impurities from contaminating the wafer front side, after step S140 and before step S150, a hydrofluoric acid solution is sprayed onto the wafer end face of the rotating wafer for a set time to specifically remove the oxide film on the wafer end face, thereby further cleaning the wafer end face. In other embodiments, the hydrofluoric acid solution is replaced with other film-removing cleaning solutions capable of removing the oxide film on the wafer front side.

[0050] In some embodiments, to ensure the wafer bevel is cleaned more thoroughly, after step S140 and before step S150, hydrofluoric acid solution is sprayed onto the wafer bevel of the rotating wafer for a set time to specifically clean the wafer bevel. The set time is determined as needed. In some embodiments, during the spraying of hydrofluoric acid solution onto the wafer bevel, the wafer is rotated at a third rotational speed, which is less than a third critical rotational speed that causes the hydrofluoric acid solution to flow down the wafer bevel along the wafer end face. If the wafer rotational speed exceeds the third rotational speed, the hydrofluoric acid solution will leave the wafer along the plane of the wafer bevel, and the wafer end face typically bends downwards from the plane of the wafer bevel, resulting in the wafer end face not being cleaned thoroughly. Of course, the third rotational speed cannot be lower than the critical speed for wafer over-etching to avoid the hydrofluoric acid solution remaining on the wafer bevel for too long, preventing wafer over-etching.

[0051] In some embodiments, the third critical speed is determined experimentally. In other embodiments, the third critical speed is calculated based on the frictional and centrifugal forces exerted on the wafer by the hydrofluoric acid solution.

[0052] S160: Repeat steps S130 to S150.

[0053] Repeatedly spraying the front side of the wafer with an oxide solution, hydrofluoric acid solution, and deionized water can result in a cleaner wafer.

[0054] In some implementations, when repeatedly executing steps S130 to S150, the first rotation speed in step S130 and the second rotation speed in step S150 need to be satisfied at least once during the execution process. That is, the wafer bevel can be cleaned only once, while the cleaning of the wafer front needs to be performed multiple times to ensure that a clean wafer front is obtained.

[0055] S170: Spray the oxide solution onto the front side of the wafer again until an oxide film is formed that completely covers the front side of the wafer.

[0056] Spraying an oxide solution onto the clean front side of a wafer can form a clean oxide film on the wafer's front side.

[0057] S180: Nitrogen gas is introduced onto the front side of the wafer to dry the wafer.

[0058] Nitrogen purging effectively removes any residual moisture and particles from the front side of the wafer, ensuring it is clean and dry. By introducing nitrogen gas onto the front side of the wafer, the gas flows to the wafer's bevels, drying the entire wafer.

[0059] In some embodiments, in order to rinse away the oxide solution on the front side of the wafer, deionized water is sprayed onto the front side of the wafer again between steps S170 and S180.

[0060] In some embodiments, steps S110 to S180 are performed in the same cleaning chamber. In other embodiments, steps S110 to S130 are performed in the same cleaning chamber. Between steps S130 and S140, the wafer rotation is stopped, and the wafer is transferred to another cleaning chamber, which is a decoction cleaning chamber. The wafer is then rotated horizontally around its center again, and the steps after S130 are performed again. Since the cleaning chambers used to perform steps S110 to S130 are equipped with beveled cleaning brushes and may also be equipped with front cleaning brushes for cleaning the front side of the wafer, transferring the wafer to another cleaning chamber can prevent impurities on the cleaning brushes from falling onto the wafer, thereby obtaining a cleaner wafer. If a chamber replacement step is performed after a certain execution of step S130, it is not necessary to replace the chamber again in subsequent steps; that is, step S130 is repeated in the other cleaning chamber. If step S130 is performed in another cleaning chamber, the front side of the wafer is not brushed when step S130 is performed.

[0061] Furthermore, between steps S130 and S140, and before the wafer is transferred to another cleaning chamber, deionized water is sprayed onto the front side of the wafer to wet it. The wetted wafer is then transferred to the other cleaning chamber, ensuring that the wafer is always covered with a cleaning solution film during the transfer process, preventing impurities from directly contacting the front side of the wafer. In other embodiments, the deionized water is replaced with other cleaning solutions that do not react with the wafer and subsequent processing solutions.

[0062] Furthermore, between steps S130 and S140, and after the wafer is transferred to another cleaning chamber, an oxide solution is sprayed again onto the front side of the wafer to remove some impurities that fell onto the front side of the wafer during the wafer transfer process, and to encapsulate some impurities that cannot be removed. In some embodiments, after spraying the oxide solution again onto the front side of the wafer in the other cleaning chamber, a hydrofluoric acid solution is sprayed onto the front side of the wafer to remove the oxide film on the wafer, thereby removing impurities encapsulated by the oxide film. Further, the steps of spraying the oxide solution again and spraying the hydrofluoric acid solution are repeated multiple times to better remove impurities from the wafer.

[0063] This application utilizes a beveled cleaning brush to specifically clean the beveled edges of the wafer, ensuring thorough cleaning. Furthermore, because the beveled cleaning brush cleans the beveled edges before spraying the oxide solution onto the wafer's front side, it prevents metal and other impurities on the beveled edges from reacting with the subsequently sprayed oxide solution, making them difficult to remove. Additionally, during the cleaning of the wafer's front side, adjusting the wafer rotation speed allows the oxide solution and hydrofluoric acid solution to flow down along the beveled edges, further cleaning them and improving the cleanliness of the beveled edges.

[0064] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0065] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A wafer cleaning method, wherein the wafer has a front side and a beveled edge adjacent to the front side, characterized in that, include: Keep the wafer rotating; Clean the beveled edge of the wafer with an impurity cleaning solution until the beveled edge of the wafer is cleaned. Spray an oxide solution onto the front side of the wafer until the oxide film formed by the reaction of the oxide solution with the wafer completely covers the front side of the wafer. Spray a film-removing cleaning solution onto the front side of the wafer to remove the oxide film on the front side of the wafer.

2. The wafer cleaning method according to claim 1, characterized in that, The impurity cleaning solution is dripped onto the beveled edge cleaning brush, and the beveled edge of the wafer is cleaned by the beveled edge cleaning brush.

3. The wafer cleaning method according to claim 1, characterized in that, During the process of spraying the oxide solution onto the front side of the wafer, the wafer is kept rotating at a first rotation speed, and the oxide solution is sprayed until the oxide film completely covers the front side and the bevel of the wafer, wherein the first rotation speed is less than a first critical rotation speed that causes the oxide solution to leave the wafer along the front side.

4. The wafer cleaning method according to claim 3, characterized in that, During the process of spraying the film removal cleaning solution onto the front side of the wafer, the wafer is kept rotating at a second rotation speed, and the film removal cleaning solution is sprayed until the oxide film on the front side and the bevel of the wafer is completely removed, wherein the second rotation speed is less than the second critical rotation speed that causes the film removal cleaning solution to leave the wafer along the front side of the wafer.

5. The wafer cleaning method according to claim 1, characterized in that, It also includes spraying deionized water onto the bevel of the wafer to remove impurities from the bevel before spraying the oxide solution onto the front side of the wafer.

6. The wafer cleaning method according to claim 1, characterized in that, It also includes spraying the film removal cleaning solution onto the bevel of the wafer after spraying the film removal cleaning solution onto the front side of the wafer to remove the oxide film on the bevel of the wafer.

7. The wafer cleaning method according to claim 6, characterized in that, During the process of spraying the stripping cleaning solution onto the bevel of the wafer, the wafer is kept rotating at a third rotational speed, which is less than the third critical rotational speed at which the stripping cleaning solution leaves the wafer along the bevel.

8. The wafer cleaning method according to claim 1, characterized in that, After the oxide solution is sprayed onto the front side of the wafer, and before the stripping cleaning solution is sprayed onto the front side of the wafer, the wafer is transferred from the current cleaning chamber to the stripping cleaning chamber.

9. The wafer cleaning method according to claim 8, characterized in that, After the wafer is transferred to the stripping cleaning chamber, and before the stripping cleaning solution is sprayed onto the front side of the wafer, the oxide solution is sprayed onto the front side of the wafer again.

10. The wafer cleaning method according to claim 9, characterized in that, After spraying the film removal cleaning solution onto the front side of the wafer, the steps of spraying the oxide solution and spraying the film removal cleaning solution are repeated in the film removal cleaning chamber until the wafer is cleaned.

11. The wafer cleaning method according to claim 10, characterized in that, It also includes passing nitrogen gas through the wafer to dry the wafer after it has been cleaned.

12. The wafer cleaning method according to claim 11, characterized in that, After the wafer is cleaned and before nitrogen gas is introduced into the wafer, an oxide liquid is sprayed onto the front side of the wafer until the oxide film formed by the reaction of the oxide liquid with the wafer completely covers the wafer.

13. A wafer cleaning apparatus, wherein the wafer has a front side and a beveled edge adjacent to the front side, characterized in that, include: Rotation unit, used to rotate the wafer; The bevel cleaning unit is used to clean the bevels of the wafer using an impurity cleaning solution. The first nozzle is used to spray oxide solution onto the front side of the wafer; The second nozzle is used to spray the film removal cleaning solution onto the front side of the wafer. The controller is configured to: control the bevel cleaning unit to clean the bevel of the wafer until the bevel of the wafer is clean; control the first nozzle to spray an oxide solution onto the front side of the wafer until the oxide film generated by the reaction of the oxide solution with the wafer completely covers the front side of the wafer; and control the second nozzle to spray the film removal cleaning solution onto the front side of the wafer to remove the oxide film on the front side of the wafer.

14. The wafer cleaning apparatus according to claim 13, characterized in that, The bevel cleaning unit includes a third nozzle and a bevel cleaning brush. The third nozzle is used to drop the impurity cleaning liquid onto the bevel cleaning brush, and the bevel cleaning brush is used to clean the bevel of the wafer.

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