Wafer processing apparatus and wafer processing method

Abstract

The application provides a wafer processing device and a wafer processing method, wherein the wafer processing device comprises a first side wall and a positioning member for supporting a wafer; when the wafer on the positioning member is processed, the first side wall is sleeved on the peripheral side of the wafer supported by the positioning member; and the first side wall is connected with a plurality of cleaning members for cleaning the inner wall of the first side wall. The application can improve the quality of wafer processing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor cleaning, and in particular to a wafer processing device and a wafer processing method. BACKGROUND

[0002] In recent years, in the wafer processing, especially in the wafer cleaning process, single wafer cleaning is widely performed, and the removal of polymer makes the organic chemical liquid containing additives such as organic solvents or organic acids be used as a chemical liquid for stripping polymer on the wafer, and the chemical liquid is sprayed on the rotating wafer. Subsequently, a rinsing process is usually performed using a cleaning liquid (including pure water) to remove the chemical liquid components remaining on the wafer, and the substrate is dried in a spin-drying manner, and then sent to the next operation process.

[0003] However, in the process of cleaning the wafer with the chemical liquid, because the chemical liquid has a large concentration, and the wafer is cleaned while rotating, many particles will condense on the side wall of the cleaning device, and the particles on the side wall are easy to fall on the wafer, thereby causing defects on the wafer, reducing the cleaning effect of the wafer, and further affecting the processing quality of the wafer. SUMMARY

[0004] To solve the above problems, the wafer processing device and the wafer processing method provided by the present application can clean the first side wall by setting multiple cleaning members, so as to prevent the particles condensed on the first side wall from falling back on the wafer to affect the processing quality of the wafer.

[0005] In a first aspect, the present application provides a wafer processing device, comprising: a first side wall and a positioning member for supporting a wafer.

[0006] When the wafer on the positioning member is processed, the first side wall is sleeved on the peripheral side of the wafer supported by the positioning member.

[0007] The first side wall is connected with multiple cleaning members, and the multiple cleaning members are used for cleaning the inner wall of the first side wall.

[0008] Optionally, the multiple cleaning members comprise multiple spray heads.

[0009] The first side wall is internally provided with a liquid delivery channel, one end of the liquid delivery channel is in communication with the water inlets of the multiple spray heads.

[0010] The wafer processing device delivers a rinsing liquid to the multiple spray heads through the liquid delivery channel to rinse the inner wall of the first side wall.

[0011] The temperature of the rinsing liquid ranges from 50 degrees Celsius to 70 degrees Celsius.

[0012] Optionally, the wafer processing device further comprises a second side wall;

[0013] When the wafer on the positioning member is processed, the second side wall is sleeved on the peripheral side of the wafer supported by the positioning member.

[0014] Optionally, the wafer processing device further comprises a first nozzle and a second nozzle;

[0015] The first nozzle is used for spraying a chemical liquid to clean the wafer, and the second nozzle is used for spraying a cleaning liquid to clean the wafer;

[0016] When the wafer is cleaned by the first nozzle and the second nozzle, the first nozzle and the second nozzle are both located above the positioning member.

[0017] Optionally, when the wafer is cleaned by the first nozzle, the first side wall is located on the peripheral side of the wafer supported by the positioning member, and the second side wall is sleeved on the peripheral side of the first side wall;

[0018] Or, when the wafer is cleaned by the first nozzle, the first side wall is located on the peripheral side of the wafer supported by the positioning member, and the second side wall is separated from the wafer supported by the positioning member.

[0019] Optionally, when the wafer is cleaned by the second nozzle, the second side wall is located on the peripheral side of the wafer supported by the positioning member, and the first side wall is separated from the wafer supported by the positioning member;

[0020] Or, when the wafer is cleaned by the second nozzle, the second side wall is located on the peripheral side of the wafer supported by the positioning member, and the first side wall is sleeved on the peripheral side of the second side wall.

[0021] Optionally, the wafer processing device comprises a bottom plate;

[0022] The positioning member is located above the bottom plate, and the positioning member is fixedly connected with the bottom plate;

[0023] The bottom plate is provided with a first opening;

[0024] The first side wall moves to the lower side of the wafer supported by the positioning member through the first opening, so as to separate the first side wall from the wafer supported by the positioning member.

[0025] The bottom plate is provided with a second opening;

[0026] The second side wall moves to the lower side of the wafer supported by the positioning member through the second opening, so as to separate the second side wall from the wafer supported by the positioning member.

[0027] Optionally, the inner wall surface of the first side wall is a concave-convex surface.

[0028] In a second aspect, the present application provides a wafer processing method, comprising:

[0029] providing a first side wall and a positioning member for supporting a wafer, the first side wall being sleeved on the peripheral side of the wafer supported by the positioning member when the wafer on the positioning member is processed;

[0030] after the wafer completes a designated processing procedure in the first side wall, starting a plurality of nozzles on the first side wall to flush the inner wall of the first side wall.

[0031] Optionally, the flushing of the inner wall of the first side wall by the plurality of nozzles on the first side wall after the wafer completes a designated processing procedure in the first side wall comprises:

[0032] before the wafer is cleaned by spraying a chemical liquid, moving the first side wall and the second side wall, or moving the second side wall, so that the first side wall is sleeved on the peripheral side of the wafer and the second side wall is detached from the wafer;

[0033] or, before the wafer is cleaned by spraying a chemical liquid, moving the first side wall so that the first side wall is sleeved on the peripheral side of the wafer and the second side wall is sleeved on the peripheral side of the first side wall;

[0034] after the wafer is cleaned by spraying a chemical liquid, moving the first side wall, or moving the first side wall and the second side wall, so that the second side wall is sleeved on the peripheral side of the wafer and the first side wall is detached from the wafer, and the wafer is cleaned by the cleaning liquid;

[0035] or, after the wafer is cleaned by spraying a chemical liquid, moving the second side wall so that the second side wall is sleeved on the peripheral side of the wafer and the first side wall is sleeved on the peripheral side of the second side wall, and the wafer is cleaned by the cleaning liquid;

[0036] when the first side wall is sleeved on the peripheral side of the second side wall or the first side wall is detached from the wafer, starting a plurality of nozzles on the first side wall to flush the inner wall of the first side wall.

[0037] The wafer processing device and the wafer processing method provided by the embodiments of the present application can clean the first side wall to remove the particles on the surface of the first side wall facing the wafer, so as to prevent the particles condensed on the first side wall from falling back to the wafer to affect the processing quality of the wafer. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A sectional view of a wafer processing device according to an embodiment of the present application;

[0039] Figure 2 A state diagram of a wafer processing device according to an embodiment of the present application cleaning a wafer by a cleaning liquid;

[0040] Figure 3 A state diagram of a wafer processing device according to an embodiment of the present application cleaning a wafer by a cleaning liquid;

[0041] Figure 4 A partial structure diagram of an inner wall of a first side wall according to an embodiment of the present application.

[0042] REFERENCE NUMERALS

[0043] 1, first side wall; 11, shower head; 12, liquid delivery channel; 13, groove; 2, second side wall; 3, positioning member; 4, bottom plate; 41, liquid discharge port; 51, first nozzle; 52, second nozzle; 6, wafer. DETAILED DESCRIPTION

[0044] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0045] In a first aspect, the present application provides a wafer processing device, comprising Figure 1 The wafer processing device is suitable for a wafer 6 cleaning process, and the wafer processing device comprises a first side wall 1, a second side wall 2, a driving member and a positioning member 3 for supporting the wafer 6. The first side wall 1 and the second side wall 2 are both annular side walls, and the first side wall 1 is connected with a plurality of cleaning members for cleaning the inner wall of the first side wall 1. The positioning member 3 is a chuck, which is used for horizontally fixing the wafer 6 on the top of the chuck. When the wafer 6 on the chuck is processed, the first side wall 1 is sleeved on the outer peripheral side of the wafer 6 supported by the positioning member 3.

[0046] The driving member can change the position of the first side wall 1 and the second side wall 2 relative to the positioning member 3. When the wafer 6 is subjected to a process on the positioning member 3 which is likely to generate impurity particles, the driving member can move the first side wall 1 to be sleeved on the peripheral side of the wafer 6 supported by the positioning member 3, so that the particles generated in the process are attached to the first side wall 1. When the wafer 6 is subjected to a process on the positioning member 3 which is not likely to generate impurity particles, the driving member can move the first side wall 1 away and move the second side wall 2 to be sleeved on the peripheral side of the wafer 6 supported by the positioning member 3, so as to prevent the impurity particles of the first side wall 1 from falling back to the wafer 6 and affecting the processing quality of the wafer 6.

[0047] Meanwhile, the cleaning member can remove the impurity particles on the first side wall 1, and when the driving member moves the first side wall 1 away, the cleaning of the first side wall 1 by the cleaning member can prevent the impurity particles from falling back to the wafer 6 and affecting the processing quality of the wafer 6.

[0048] Further, the plurality of cleaning members include a plurality of spray heads 11 which are fixedly arranged on the top of the first side wall 1. The wafer processing device can remove the impurity particles on the inner wall of the first side wall 1 by supplying liquid or high-pressure gas to the spray heads 11. In this embodiment, the wafer processing device cleans the first side wall 1 by supplying flushing liquid to the spray heads 11.

[0049] The first side wall 1 is internally provided with a liquid supply channel 12 which is connected to the water inlets of the plurality of spray heads 11. The wafer processing device supplies flushing liquid to the plurality of spray heads 11 through the liquid supply channel 12 to flush the inner wall of the first side wall 1. The temperature of the flushing liquid ranges from 50 to 70 degrees Celsius. In this example, the temperature of the flushing liquid is 60 degrees Celsius. By limiting the temperature of the flushing liquid, not only can the flushing effect on the impurity particles condensed on the first side wall 1 be improved, but also the first side wall 1 can be heated, which reduces the adhesion of the impurity particles condensed on the first side wall 1 to the first side wall 1, further improving the flushing effect on the first side wall 1.

[0050] In this embodiment, the combination of the driving member and the cleaning member can prevent the impurity particles of the first side wall 1 from falling back to the wafer 6 and affecting the processing quality of the wafer 6. Figure 2 and Figure 3The wafer processing device further comprises a bottom plate 4, a first nozzle 51 and a second nozzle 52. The first nozzle 51 is used for spraying a chemical liquid to clean the wafer 6, and the second nozzle 52 is used for spraying a cleaning liquid to clean the wafer 6. When the first nozzle 51 and the second nozzle 52 clean the wafer 6, the first nozzle 51 and the second nozzle 52 are both moved above the wafer 6 to clean the wafer 6. The positioning member 3 is above the bottom plate 4, and the positioning member 3 is fixedly connected with the bottom plate 4. When the first nozzle 51 or the second nozzle 52 cleans the wafer 6, the positioning member 3 is further used to drive the wafer 6 to rotate. The bottom plate 4 is provided with a liquid discharge port 41, which is beneficial to guide the liquid on the bottom plate 4 out of the wafer processing device.

[0051] When the first nozzle 51 cleans the wafer 6, the driving member moves the first side wall 1 to the peripheral side of the positioning member 3, so that the wafer 6 is cleaned in the first side wall 1. When the second nozzle 52 cleans the wafer 6, the driving member moves the second side wall 2 to the peripheral side of the positioning member 3, and the inner wall of the first side wall 1 is cleaned by the plurality of nozzles 11.

[0052] The wafer processing device can change the relative position of the first side wall 1 and the second side wall 2 relative to the positioning member 3 by using different driving modes of the driving member according to the different relative positions of the first side wall 1 and the second side wall 2 and the connection relationship between the first side wall 1 and the second side wall 2. The embodiment is specifically described by the following several ways.

[0053] Way one: combined with Figure 1 , Figure 2 and Figure 3 , the first side wall 1 is located on the inner side of the second side wall 2, and the bottom plate 4 is provided with a first opening and a second opening. The first opening is matched with the first side wall 1, and the second opening is matched with the second side wall 2. The first side wall 1 is slidably connected with the bottom plate 4 in the up-down direction through the first opening, and the second side wall 2 is slidably connected with the bottom plate 4 in the up-down direction through the second opening. The driving member is connected with the first side wall 1 and the second side wall 2 at the same time.

[0054] Before the first nozzle 51 performs cleaning on the wafer 6, the driving member drives the first side wall 1 to rise above the bottom plate 4, so that the first side wall 1 is sleeved on the peripheral side of the wafer 6; and the second side wall 2 can be located on the peripheral side of the first side wall 1 or below the wafer 6 supported by the positioning member 3. In this embodiment, the driving member controls the second side wall 2 to be located below the wafer 6 supported by the positioning member 3. After the first nozzle 51 finishes cleaning the wafer 6, and before the second nozzle 52 performs cleaning on the wafer 6, the driving member drives the first side wall 1 to descend to a position below the wafer 6 supported by the positioning member 3, so as to separate the first side wall 1 from the wafer 6 supported by the positioning member 3, and drives the second side wall 2 to rise above the bottom plate 4, so that the second side wall 2 is sleeved on the peripheral side of the wafer 6 supported by the positioning member 3; and at the same time, the plurality of nozzles 11 are controlled to be opened to clean the inner wall of the first side wall 1.

[0055] The second side wall 2 is located on the outside of the first side wall 1, and the bottom plate 4 is provided with a first opening; the first opening is matched with the first side wall 1; the first side wall 1 is connected with the bottom plate 4 in the up-down direction through the first opening; the second side wall 2 is fixedly arranged above the bottom plate 4; and the driving member is connected with the first side wall 1.

[0056] Before the first nozzle 51 performs cleaning on the wafer 6, the driving member drives the first side wall 1 to rise above the bottom plate 4, so that the first side wall 1 is sleeved on the peripheral side of the wafer 6, and the second side wall 2 is sleeved on the peripheral side of the first side wall 1. After the first nozzle 51 finishes cleaning the wafer 6, and before the second nozzle 52 performs cleaning on the wafer 6, the driving member drives the first side wall 1 to descend below the wafer 6, so that the first side wall 1 is separated from the wafer 6 supported by the positioning member 3, and the second side wall 2 is directly sleeved on the peripheral side of the positioning member 3, so as to prevent the cleaning liquid from splashing; and at the same time, the plurality of nozzles 11 are controlled to be opened to clean the inner wall of the first side wall 1.

[0057] The second side wall 2 is located on the outside of the first side wall 1, and the bottom plate 4 is provided with a first opening and a second opening; the first opening is matched with the first side wall 1, and the second opening is matched with the second side wall 2; the first side wall 1 is connected with the bottom plate 4 in the up-down direction through the first opening, and the second side wall 2 is connected with the bottom plate 4 in the up-down direction through the second opening; and the driving member is connected with the first side wall 1 and the second side wall 2 at the same time.

[0058] Before the first nozzle 51 cleans the wafer 6, the driving member drives the first side wall 1 to rise above the bottom plate 4, so that the first side wall 1 is sleeved on the outer peripheral side of the wafer 6; and the second side wall 2 is below the wafer 6 supported by the positioning member 3. After the first nozzle 51 finishes cleaning the wafer 6, and before the second nozzle 52 cleans the wafer 6, the driving member drives the first side wall 1 to descend below the wafer 6, so that the first side wall 1 is separated from the sleeve of the wafer 6 supported by the positioning member 3, and drives the second side wall 2 to rise above the bottom plate 4, so that the second side wall 2 is sleeved on the outer peripheral side of the wafer 6 supported by the positioning member 3; and simultaneously controls the multiple nozzles 11 to be opened to clean the inner wall of the first side wall 1. Alternatively, after the first nozzle 51 finishes cleaning the wafer 6, and before the second nozzle 52 cleans the wafer 6, the driving member only drives the second side wall 2 to rise above the bottom plate 4, so that the second side wall 2 is sleeved on the outer peripheral side of the wafer 6 supported by the positioning member 3, and the first side wall 1 is sleeved on the outside of the second side wall 2; and simultaneously controls the multiple nozzles 11 to be opened to clean the inner wall of the first side wall 1.

[0059] The fourth mode: the first side wall 1 is located outside the second side wall 2, and the bottom plate 4 is provided with a second opening; the second opening is matched with the second side wall 2; the second side wall 2 is connected with the bottom plate 4 in the up-down direction through the second opening, and the first side wall 1 is fixedly arranged above the bottom plate 4; the driving member is connected with the second side wall 2.

[0060] Before the first nozzle 51 cleans the wafer 6, the driving member drives the second side wall 2 to descend below the wafer 6, so that the first side wall 1 is directly sleeved on the outer peripheral side of the positioning member 3, to prevent the chemical liquid from splashing. After the first nozzle 51 finishes cleaning the wafer 6, and before the second nozzle 52 cleans the wafer 6, the driving member drives the second side wall 2 to rise above the bottom plate 4, so that the second side wall 2 is directly sleeved on the outer peripheral side of the positioning member 3, to prevent the cleaning liquid from splashing; and simultaneously controls the multiple nozzles 11 to be opened to clean the inner wall of the first side wall 1.

[0061] By replacing the wafer 6 on the positioning member 3, the wafer processing device can continuously clean the wafer 6 in any one of the above-mentioned modes, while preventing the chemical liquid and the cleaning liquid from splashing, and improving the cleaning quality of the wafer 6, effectively preventing the impurity particles condensed by the chemical liquid on the side wall from falling on the wafer 6 to reduce the quality of the wafer 6. In the embodiment, the description of the position of the first side wall 1 descending below the wafer 6 and the first side wall 1 being below the wafer 6 is that the top of the first side wall 1 is connected with the bottom plate 4 through the first opening; and the description of the position of the second side wall 2 descending below the wafer 6 and the second side wall 2 being below the wafer 6 is that the top of the second side wall 2 is connected with the bottom plate 4 through the second opening.

[0062] In combination Figure 4 The inner wall of the first side wall 1 is provided with a plurality of grooves 13 to form a concave-convex surface. The grooves 13 can be polygonal or circular. In the embodiment, the grooves 13 are square. The concave-convex surface prevents the impurity particles condensed on the inner wall of the first side wall 1 from being too large, thereby increasing the difficulty of cleaning the first side wall 1.

[0063] In an alternative embodiment, after the first nozzle 51 and the second nozzle 52 finish cleaning the wafer 6, the positioning member 3 is further used to drive the wafer 6 to rotate to perform a drying process on the wafer 6. Meanwhile, after the first nozzle 51 and the second nozzle 52 finish cleaning the wafer 6, and the positioning member 3 drives the wafer 6 to perform the drying process, the second side wall 2 is located at the peripheral side of the wafer 6, and the first side wall 1 is located below the wafer 6 or at the peripheral side of the second side wall 2.

[0064] In a second aspect, the present application provides a wafer processing method in combination Figures 1 to 3 The method comprises: providing a first side wall 1 and a positioning member 3 for supporting a wafer 6, when processing the wafer 6 on the positioning member 3, the first side wall 1 is sleeved on the peripheral side of the wafer 6 supported by the positioning member 3; after the wafer 6 completes a designated processing procedure in the first side wall 1, a plurality of nozzles 11 on the first side wall 1 are started to flush the inner wall of the first side wall 1. In this way, when the wafer 6 is processed, the impurity particles condensed on the first side wall 1 are removed by the plurality of nozzles 11, preventing the impurity particles from falling on the wafer 6 when naturally falling off, so as to affect the processing quality of the wafer 6.

[0065] In the embodiment, after the wafer 6 completes a designated processing procedure in the first side wall 1, the plurality of nozzles 11 on the first side wall 1 are started to flush the inner wall of the first side wall 1, which comprises: before the wafer 6 is cleaned by spraying a chemical liquid, the first side wall 1 and the second side wall 2 are moved, or the second side wall 2 is moved, so that the first side wall 1 is sleeved on the peripheral side of the wafer 6, and the second side wall 2 is separated from the wafer 6. Or, before the wafer 6 is cleaned by spraying a chemical liquid, the first side wall 1 is moved so that the first side wall 1 is sleeved on the peripheral side of the wafer 6, and the second side wall 2 is sleeved on the peripheral side of the first side wall 1.

[0066] After the wafer 6 is cleaned by spraying the chemical liquid, the first side wall 1 is moved, or the first side wall 1 and the second side wall 2 are moved, so that the second side wall 2 is sleeved on the peripheral side of the wafer 6 and the first side wall 1 is separated from the wafer 6, and the wafer 6 is cleaned by the cleaning liquid. Or, after the wafer 6 is cleaned by spraying the chemical liquid, the second side wall 2 is moved, so that the second side wall 2 is sleeved on the peripheral side of the wafer 6 and the first side wall 1 is sleeved on the peripheral side of the second side wall 2, and the wafer 6 is cleaned by the cleaning liquid.

[0067] When the first side wall 1 is sleeved on the peripheral side of the second side wall 2 or the first side wall 1 is separated from the wafer 6, the plurality of nozzles 11 on the first side wall 1 are started to flush the inner wall of the first side wall 1. For details, refer to the four modes described above, which will not be repeated here.

[0068] By alternately using different side walls as the side wall of the processing chamber of the wafer 6 in different processes, and cleaning the side wall prone to condensation of impurity particles, the impurity particles can be effectively prevented from falling on the wafer 6 when naturally falling off, so as to affect the processing quality of the wafer 6.

[0069] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A wafer processing apparatus, characterized in that, The application relates to a wafer processing device and a wafer processing method. The device comprises a first side wall, a second side wall, a bottom plate, a first nozzle, a second nozzle, a driving element and a positioning element for supporting a wafer; The positioning element is located above the bottom plate and is fixedly connected with the bottom plate; the driving element is connected with the first side wall and the second side wall respectively; the first nozzle is used for spraying a chemical liquid to clean the wafer; and the second nozzle is used for spraying a cleaning liquid to clean the wafer; the first side wall and the second side wall are both slidably connected with the bottom plate along the up-down direction; The driving element is used for changing the position of the first side wall and the second side wall relative to the positioning element; the bottom plate is provided with a first opening; the first side wall moves to the lower side of the wafer supported by the positioning element through the first opening, so as to separate the first side wall from the wafer supported by the positioning element; the bottom plate is provided with a second opening; the second side wall moves to the lower side of the wafer supported by the positioning element through the second opening, so as to separate the second side wall from the wafer supported by the positioning element; When the first nozzle is used for cleaning the wafer, the first side wall is located at the peripheral side of the wafer supported by the positioning element, the second side wall is sleeved at the peripheral side of the first side wall, or the driving element controls the second side wall to be located at the lower side of the wafer supported by the positioning element; When the second nozzle is used for cleaning the wafer, the second side wall is located at the peripheral side of the wafer supported by the positioning element, and the driving element controls the first side wall to be located at the lower side of the wafer supported by the positioning element; The first side wall is connected with a plurality of cleaning elements, and the plurality of cleaning elements are used for cleaning the inner wall of the first side wall; Thus, the impurity particles generated by the chemical liquid are removed.

2. The wafer processing apparatus of claim 1, wherein The plurality of cleaning elements comprise a plurality of nozzles; The inner wall of the first side wall is provided with a liquid conveying channel, one end of the liquid conveying channel is communicated with the water inlets of the plurality of nozzles; The wafer processing device conveys the flushing liquid to the plurality of nozzles through the liquid conveying channel, so as to flush the inner wall of the first side wall; The temperature range of the flushing liquid is 50-70 DEG C.

3. The wafer processing apparatus of claim 1, wherein When the first nozzle and the second nozzle are used for cleaning the wafer, the first nozzle and the second nozzle are both located above the positioning element.

4. The wafer processing apparatus of claim 1, wherein The inner wall surface of the first side wall is a concave-convex surface.

5. A wafer processing method characterized by, The wafer processing method is realized by using the wafer processing device as claimed in any one of claims 1 to 4, and the method comprises the following steps: A first side wall and a positioning element for supporting a wafer are provided; when the wafer on the positioning element is cleaned by using a chemical liquid, the first side wall is sleeved at the peripheral side of the wafer supported by the positioning element; After the wafer is cleaned by using the chemical liquid in the first side wall, a plurality of nozzles on the first side wall are started to flush the inner wall of the first side wall.

6. The wafer processing method of claim 5, wherein The step of starting the plurality of nozzles on the first side wall to flush the inner wall of the first side wall after the wafer is cleaned by using the chemical liquid in the first side wall comprises the following steps: moving the first side wall and the second side wall, or moving the second side wall, to fit the first side wall around the periphery of the wafer and to disengage the second side wall from the wafer, before cleaning the wafer by spraying a chemical liquid; or, moving the first side wall to fit the first side wall around the periphery of the wafer and to fit the second side wall around the periphery of the first side wall, before cleaning the wafer by spraying a chemical liquid; moving the first side wall, or moving the first side wall and the second side wall, to fit the second side wall around the periphery of the wafer and to disengage the first side wall from the wafer, after cleaning the wafer by spraying a chemical liquid; activating the plurality of nozzles on the first side wall to flush the inner wall of the first side wall, when the first side wall is fitted around the periphery of the second side wall or is disengaged from the wafer.

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