Wafer buffer layer bevel cleaning method and device

Abstract

The present application provides a wafer buffer layer bevel cleaning method and device. The cleaning method comprises: rotating a wafer, and spraying a first cleaning solution to a surface of the wafer to remove a buffer layer at the bevel of the wafer, wherein a byproduct mark is formed on the surface of the wafer; obtaining the position of the byproduct mark, and recording the position as a mark position; keeping the wafer rotating, and spraying a second cleaning solution to the mark position to remove the byproduct mark on the surface of the wafer; and spraying a rinsing solution to the surface of the wafer to rinse the wafer.

Description

Cleaning methods and equipment for wafer buffer layer edges

[0001] This application claims priority to Chinese Patent Application No. 202510066274.9, filed on January 16, 2025, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This application relates to the field of semiconductor manufacturing, and more particularly to a method and apparatus for cleaning the edge of a wafer buffer layer. Background Technology

[0003] Due to wafer design requirements, buffer layers are often sputtered onto the wafer to achieve functions such as buffering, increasing adhesion between film layers, and isolation. Depending on the material, the buffer layer can also be called an insulating layer or an isolation layer. At the wafer edge, due to the unevenness of the edge region, the insulating material of the buffer layer is prone to peeling or particle contamination due to weak adhesion, thermal stress, back-side cleaning, or dry etching, reducing wafer yield. Therefore, edge cleaning of the buffer layer is necessary.

[0004] During edge removal of the buffer layer, due to the diverse chemical reactions and multiple reaction directions, byproducts generated by the cleaning solution in the buffer layer edge area are carried into the wafer by the overflow of the cleaning solution when the wafer rotates at high speed, and accumulate, forming abnormal marks. The adhesion between the abnormal marks formed by the accumulation of byproducts and the wafer surface is relatively weak, and they may fall off and contaminate during wafer transport or shipping, thereby reducing the product yield of the wafer.

[0005] How to clean the byproduct marks generated during the edge cleaning process of the wafer buffer layer and avoid them falling off and contaminating the wafer is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the problems existing in the prior art, this application provides a method for cleaning the edge of a wafer buffer layer, comprising:

[0007] The wafer is rotated and a first cleaning solution is sprayed onto the wafer surface to remove the buffer layer at the edge of the wafer, and by-product marks are formed on the wafer surface.

[0008] The location of the byproduct imprint is obtained and recorded as the mark location;

[0009] While keeping the wafer rotated, a second cleaning solution is sprayed onto the marked locations to remove byproduct marks on the wafer surface;

[0010] A rinsing solution is sprayed onto the surface of the wafer to rinse it.

[0011] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the marking position is determined by the distance between the by-product imprint and the wafer edge.

[0012] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the marking position is determined by the distance between the inner circle of the by-product imprint and the edge of the wafer.

[0013] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the contact point of the first cleaning solution is on the cleaning line of the wafer, and the distance between the cleaning line and the edge of the wafer is the width of the bevel of the wafer.

[0014] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the second cleaning liquid is sprayed onto the marked position by moving a nozzle, and the first cleaning liquid is switched to the second cleaning liquid during the movement of the nozzle.

[0015] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the rotational speed of the wafer remains unchanged when the first cleaning liquid is sprayed onto the wafer surface and when the second cleaning liquid is sprayed onto the marked position.

[0016] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the flow rate of the first cleaning solution is the same as the flow rate of the second cleaning solution.

[0017] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the first cleaning solution is any one of DHF, HF, SC1, SC2 or a mixture of HF and HNO3, and the second cleaning solution is any one of DHF, HF, SC1, SC2 or a mixture of HF and HNO3.

[0018] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the first cleaning solution and the second cleaning solution are the same chemical solution.

[0019] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the rinsing solution is deionized water.

[0020] According to the cleaning method for the edge of a wafer buffer layer provided in this application, the contact point of the first cleaning liquid and / or the second cleaning liquid is closer to the edge of the wafer than the orthogonal projection of the nozzle on the wafer.

[0021] According to the cleaning method for the edge of a wafer buffer layer provided in this application, when the first cleaning liquid is sprayed onto the wafer surface and / or the second cleaning liquid is sprayed onto the marked position, the nozzle forms an inclined angle of less than 90 degrees with the wafer surface.

[0022] According to the cleaning method for the edge of a wafer buffer layer provided in this application, before spraying the first cleaning liquid onto the wafer surface, the first cleaning liquid is pre-sprayed at a location outside the wafer for a preset time.

[0023] This application also provides a cleaning apparatus for the edge of a wafer buffer layer, comprising:

[0024] A chuck is used to carry and rotate a wafer;

[0025] The nozzle, connected to an external liquid supply device, is used to spray chemical liquid onto the wafer;

[0026] The acquisition unit is used to acquire the location of by-product imprints on the wafer surface and record them as the mark location;

[0027] The controller is configured to: control the nozzle to spray a first cleaning fluid onto the wafer cleaning line to remove the buffer layer at the edge of the wafer; control the acquisition unit to acquire the position of the by-product mark on the wafer surface; control the nozzle to move according to the acquired mark position so that the contact point of the second cleaning fluid sprayed by the nozzle is located at the mark position; and control the nozzle to move to the rinsing position to rinse the surface of the wafer.

[0028] The wafer buffer layer cleaning method provided in this application first rotates the wafer and sprays a first cleaning solution onto the wafer surface to remove the buffer layer at the wafer edge, forming a ring of by-product marks on the wafer surface; then, the position of the by-product marks is obtained and marked as the mark position, the wafer is kept rotating, and a second cleaning solution is sprayed onto the mark position to remove the by-product marks at the mark position; finally, a rinsing solution is sprayed onto the wafer surface to rinse the wafer.

[0029] Precise rinsing was performed to target byproduct marks, effectively solving the problem of byproduct marks generated during the cleaning process at the edge of the buffer layer and improving wafer yield.

[0030] Overview of the attached figures

[0031] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 is a schematic diagram of the structure of a wafer cleaning device according to an embodiment of this application;

[0033] Figure 2 is a schematic flowchart of a method for cleaning the edge of a wafer buffer layer according to an embodiment of this application;

[0034] Figure 3 is a schematic diagram of by-product imprints according to an embodiment of this application;

[0035] Figure 4 is a schematic diagram of the nozzle contact point location according to an embodiment of this application;

[0036] Figure 5 is a schematic diagram of the cleaning result according to an embodiment of this application.

[0037] Preferred embodiments of the present invention

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] The wafer buffer layer cleaning method provided in this application is implemented in a single wafer cleaning chamber.

[0040] Research has revealed two main factors influencing the location of by-product imprints. First, the required process position on the wafer, specifically the landing point of the cleaning solution. Second, even with the cleaning solution landing point remaining constant, the wafer's rotational speed also affects the location of the by-product imprints. A slower wafer rotation results in less centrifugal force, increasing the area of ​​cleaning solution overflowing towards the wafer's center. Consequently, the final location of the by-product imprints will be more towards the wafer's center relative to the cleaning line.

[0041] How to clean the abnormal marks generated on the wafer surface during the cleaning process at the edge of the buffer layer is the technical problem to be solved by this application.

[0042] This application provides a cleaning method for the edge of a wafer buffer layer, which is performed by the wafer cleaning equipment shown in FIG1. ​​The wafer cleaning equipment includes a chuck 101 and a nozzle 102, which are disposed in the wafer cleaning chamber to clean the wafer 103.

[0043] The inventor's known method for cleaning the edge of a wafer buffer layer generally consists of two parts. First, based on wafer process requirements, a cleaning solution is used to remove the buffer layer edge area that needs cleaning. Then, a rinsing solution is used to rinse the wafer surface to remove any residual substances.

[0044] Referring to Figures 2 to 4, the cleaning method for the edge of the wafer buffer layer according to an embodiment of this application includes the following steps:

[0045] S110, Remove the buffer layer at the wafer edge. Move the nozzle based on the wafer edge cleaning width so that the contact point of the first cleaning fluid sprayed from the nozzle is located on the cleaning line, cleaning the wafer edge.

[0046] In this step, based on the wafer's process requirements, the edge cleaning width of the wafer, i.e., the distance between the cleaning line and the wafer edge, can be determined. The nozzle is moved for the first time so that the first cleaning solution sprayed from the nozzle lands on the cleaning line, thereby cleaning the wafer edge area.

[0047] During the cleaning process of the wafer buffer layer edge area, the first cleaning solution reacts with the buffer layer at the wafer edge and further hydrolyzes to form byproducts. Since the nozzle position for spraying the cleaning solution is fixed, while the wafer is rotating at high speed, the byproducts generated on the wafer surface continuously move towards the wafer center and accumulate, ultimately appearing as ring-shaped byproduct marks centered on the wafer's center. The black lines in Figure 3 represent localized byproduct marks on the wafer surface.

[0048] S120. Remove by-product marks on the wafer. Obtain the marking position of the by-product mark, and move the nozzle based on the marking position so that the contact point of the second cleaning liquid sprayed from the nozzle is at the marking position, thereby cleaning the by-product mark.

[0049] After the first cleaning solution removes the buffer layer at the wafer edge, the marking position is determined by measuring the distance between the by-product imprint and the wafer edge. Since the wafer rotates during the by-product imprint removal process, the by-product imprint is located at any point on the annular line. The marking position is closer to the wafer's internal region than the process position, which is the location of the edge cleaning line, i.e., the contact point of the first cleaning solution during edge cleaning. During the buffer layer edge cleaning process, since the first cleaning solution is an aqueous solution, it reacts with the buffer layer edge, further hydrolyzing to produce by-products. These by-products accumulate along the edge cleaning line towards the wafer center due to wafer rotation and the overflow of the first cleaning solution. In some embodiments, the marking position of the by-product imprint is obtained using an optical microscope or a measuring instrument; this is not limited here.

[0050] After obtaining the marked position of the by-product imprint, the position of the nozzle 102 is moved a second time based on the control unit of the wafer cleaning equipment. In some embodiments, the position of the nozzle 102 can be changed by altering the length of the robotic arm connected to the nozzle 102.

[0051] It should be noted that, in order to avoid sputtering of the second cleaning solution on the wafer surface, the nozzle is not perpendicular to the wafer surface, that is, there is an angle of inclination of less than 90 degrees between the nozzle and the wafer surface. At the same time, in order to minimize the amount of waste liquid flowing towards the center of the wafer after cleaning, the contact point of the second cleaning solution is closer to the edge of the wafer than the orthogonal projection of the nozzle on the wafer.

[0052] Referring to Figure 1, in some embodiments, the nozzle 102 is tilted at a certain angle to the surface of the wafer 103 to ensure that the contact point of the second cleaning fluid ejected from the nozzle 102 is located at the marked position, thus cleaning the by-product imprints. Furthermore, because the nozzle 102 is tilted towards the wafer edge, if the second cleaning fluid ejected from the nozzle splashes, the splashing will be biased towards the wafer edge and will not affect the central region of the wafer. In some embodiments, a large number of by-products are formed on the surface of the wafer 103, and the by-product imprints formed on the surface of the wafer 103 are annular regions of a certain width. Therefore, the contact point of the second cleaning fluid should be located within the inner circle of the annular imprint to thoroughly clean the by-product imprints.

[0053] In some embodiments, the first cleaning solution and the second cleaning solution are the same chemical solution, which can not only remove the edge of the buffer layer membrane, but also remove by-product imprints, such as dilute hydrofluoric acid (DHF), hydrofluoric acid (HF), SC1, SC2, or a mixture of HF and HNO3, for example.

[0054] In some embodiments, the cleaning solution can be switched directly during the nozzle movement based on the marked position. This involves maintaining a continuous supply of liquid from the nozzle, switching from a first cleaning solution to a second cleaning solution, and then maintaining a fixed spray position after the nozzle moves to the point where the second cleaning solution contacts the marked position. The second cleaning solution is then used to remove byproduct marks. Continuous liquid supply during nozzle movement ensures a stable and more uniform liquid film on the wafer surface, thus optimizing wafer yield.

[0055] S130. Rinse the wafer surface. Move the nozzle toward the center of the wafer and switch the second cleaning solution to the rinsing solution, so that the contact point of the rinsing solution sprayed from the nozzle is at the rinsing position, and rinse the wafer surface.

[0056] After cleaning the by-product imprints with the second cleaning solution, the wafer surface needs to be rinsed again to remove impurities and ensure its cleanliness. In this step, the nozzle 102 is moved a third time towards the wafer center. During this movement, the cleaning solution supplied by the nozzle 102 is switched from the second cleaning solution to a rinsing solution, ensuring that the rinsing solution sprayed from the nozzle lands at the rinsing position. The rinsing position is closer to the wafer center than the marking position; that is, the distance between the rinsing position and the wafer edge is greater than the distance between the marking position and the wafer edge. In one specific embodiment, the rinsing position is the wafer center.

[0057] The nozzle is moved a third time so that the rinsing fluid sprayed from the nozzle lands at the rinsing position, rinsing the wafer surface. In the previous steps, the second cleaning fluid may have generated some sputtered material during the removal of byproduct marks, which may have landed on the wafer surface. To avoid contamination due to overflow and ensure the cleanliness of the wafer surface, the nozzle is moved further towards the center of the wafer, and the second cleaning fluid sprayed from the nozzle is switched to the rinsing fluid.

[0058] In some embodiments, the first and second cleaning solutions serve as descaling solutions, namely, the aforementioned DHF, HF, SC1, SC2, or a mixture of HF and HNO3. The rinsing solution is deionized water, used to rinse the wafer surface and remove residues after cleaning the by-product markings. The wafer buffer layer by-product marking cleaning method of this application involves moving the nozzle based on wafer process requirements and using the first cleaning solution to clean the edge of the wafer buffer layer. After obtaining the marking position of the by-product markings, the nozzle is moved a second time based on the machine control of the wafer cleaning equipment, ensuring the contact point of the second cleaning solution sprayed from the nozzle is at the marking position for precise removal of the by-product markings. Then, the nozzle is moved a third time towards the wafer center, and the second cleaning solution is switched to the rinsing solution to rinse the wafer surface, thereby improving wafer yield.

[0059] In some embodiments, when the nozzle continuously supplies liquid during the nozzle movement, it is necessary to control the wafer rotation speed to remain constant. That is, during the nozzle movement, the first cleaning liquid and the second cleaning liquid are connected in real time, and there will be no gap period when the nozzle stops supplying liquid. This makes the liquid film on the wafer surface more stable, reduces the impact of the cleaning liquid connection on the wafer surface, and optimizes the rinsing effect.

[0060] Referring to Figure 4, the relative positions of the cleaning line, by-product mark markings, and rinsing position on the wafer surface of wafer w are shown in Figure 3. On wafer w, the first annular dashed line 510 is the cleaning line, that is, the position of the first cleaning liquid contact point when the nozzle moves for the first time; the black annular line 520 is the by-product mark position, that is, the position of the second cleaning liquid contact point after the nozzle moves for the second time; the second annular dashed line 530 is the rinsing position, that is, the position of the rinsing liquid contact point after the nozzle moves for the third time.

[0061] In some embodiments, the tilt angle between the nozzle and the wafer surface remains unchanged, that is, the nozzle is tilted towards the edge of the wafer to ensure that the first cleaning fluid and the second cleaning fluid sprayed from the nozzle do not contaminate the central area of ​​the wafer when cleaning the cleaning lines and marking positions.

[0062] In some embodiments, the flow rates of the first cleaning fluid, the second cleaning fluid, and the rinsing fluid supplied by the nozzle are kept consistent to improve the uniformity of the liquid film on the wafer surface.

[0063] It should also be noted that, since the hydrolysis reaction is endothermic, the temperature of the heating pad on which the wafer is placed also has a certain impact on the strength of the byproduct imprint. High temperatures promote the hydrolysis reaction; therefore, lowering the heating pad temperature can inhibit the hydrolysis reaction, thus reducing the amount of byproducts generated. Therefore, during the cleaning of byproduct imprints in the wafer buffer layer, it is essential to ensure that the temperature of the heating pad is below a preset temperature to further reduce byproducts. In some embodiments, the preset temperature can be 30-60 degrees Celsius.

[0064] In one embodiment, a method for cleaning wafer buffer layer by-product imprints of this application with a buffer layer composition of Ta / TaN is described in detail.

[0065] To prevent Cu atoms from diffusing into the substrate material and affecting wafer performance, a buffer layer is typically deposited before Cu electroplating to isolate Cu from the substrate. This buffer layer is composed of Ta / TaN. After electroplating on the buffer layer, since no Cu film is formed in the edge areas, the buffer layer in these areas needs to be removed. However, chemical mechanical polishing (CMP) cannot remove the buffer layer from the wafer edges, and the film in the edge areas is easily peeled off due to thermal and mechanical stress during CMP. Therefore, Ta / TaN removal is necessary in the edge areas after Cu electroplating.

[0066] In one embodiment, a mixture of HF and HNO3 is used to remove the edges of TaN / Ta. The following example illustrates a wafer edge cleaning step:

[0067] First, external pre-spraying is performed. Before wafer edge cleaning, the nozzle is positioned outside the wafer, and the first cleaning solution is sprayed at this location. In the initial stage of spraying the first cleaning solution, there are unstable flow rate fluctuations, which affect the process accuracy. Therefore, the wafer is pre-sprayed for a preset time until the flow rate of the first cleaning solution sprayed from the nozzle stabilizes before edge cleaning begins.

[0068] Then, edge cleaning of the buffer layer is performed. In this embodiment, the position of the cleaning line required by the wafer process is determined by the bevel width of the wafer edge, and the distance between the cleaning line and the wafer edge is the bevel width of the wafer. The nozzle is moved for the first time so that the contact point of the first cleaning liquid sprayed from the nozzle is located at the cleaning line. At this point, the first cleaning liquid, namely a mixture of HF and HNO3, is used to clean the wafer edge and remove the edge of the buffer layer.

[0069] During edge cleaning, the mixture of HF and HNO3 reacts with TaN / Ta to produce fluorotantalic acid or fluorotantalate. The hydrolysis products generated during hydrolysis overflow and accumulate with the mixture of HF and HNO3 towards the wafer center, forming byproduct imprints.

[0070] After the buffer layer edge cleaning is completed, the marked position of the by-product imprint is obtained, that is, the distance between the by-product imprint and the wafer edge is obtained. The nozzle is moved for the second time, and the nozzle continuously supplies a mixture of HF and HNO3 so that the liquid contact point of the nozzle is located at the marked position, and the by-product imprint position is cleaned for a period of time.

[0071] Finally, the nozzle is moved towards the center of the wafer for the third time. During the movement, the mixture of HF and HNO3 sprayed from the nozzle is switched to deionized water, so that the contact point of the deionized water is located at the rinsing position. The rinsing position is closer to the center of the wafer than the marked position. The wafer surface is then rinsed with deionized water.

[0072] In some embodiments, during the movement of the nozzle, the rotational speed of the wafer is kept constant so that the liquid film formed by the cleaning fluid sprayed from the nozzle on the wafer surface is more stable and uniform.

[0073] Referring to Figures 3 and 5, these are schematic diagrams before cleaning the by-product marks of the wafer buffer layer. The black lines in Figure 3 represent the by-product marks, and Figure 5 is a schematic diagram of the wafer surface after using the cleaning method for the edge of the wafer buffer layer of this application. The by-product marks have disappeared.

[0074] Referring again to Figure 1, this application also provides a cleaning apparatus for the edge of a wafer buffer layer, including a chuck 101, a nozzle 102, an acquisition unit, and a controller. The chuck 101 is used to carry and rotate the wafer. The nozzle 102 is connected to an external liquid supply device for spraying chemical liquid onto the wafer. The acquisition unit is used to acquire the marking positions of by-product imprints. In some embodiments, the acquisition unit may be a communication module of an optical microscope or a measuring instrument, through which the marking positions of by-product imprints on the wafer are acquired.

[0075] A controller is used to control the movement of the nozzle. More specifically, the controller is configured to: control the movement of the nozzle based on process requirements, so that the contact point of the first cleaning fluid sprayed from the nozzle is located on the cleaning line required by the process, and spray the first cleaning fluid onto the cleaning line through the nozzle to clean the wafer edge. During the cleaning of the wafer edge, by-product marks of a certain width are generated at a certain distance from the cleaning line towards the wafer center. Then, the controller acquires the marking position of the by-product marks through the control acquisition unit, and then moves the nozzle a second time based on the marking position, so that the contact point of the second cleaning fluid sprayed from the nozzle is located at the marking position, and performs targeted cleaning of the by-product marks generated at the wafer edge. Finally, in order to thoroughly rinse the wafer surface to remove all impurities, the controller controls the nozzle to move a third time towards the wafer center, so that the rinsing fluid sprayed from the nozzle can rinse the wafer surface.

[0076] Other details regarding the cleaning equipment can be found in the process described above with reference to Figure 2, and will not be elaborated upon here.

[0077] In the description of this application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0078] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0079] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for cleaning the edge of a wafer buffer layer, characterized in that, include: The wafer is rotated and a first cleaning solution is sprayed onto the wafer surface to remove the buffer layer at the edge of the wafer, and by-product marks are formed on the wafer surface. The location of the byproduct imprint is obtained and recorded as the mark location; While keeping the wafer rotated, a second cleaning solution is sprayed onto the marked locations to remove byproduct marks on the wafer surface; A rinsing solution is sprayed onto the surface of the wafer to rinse it.

2. The cleaning method for the edge of the wafer buffer layer according to claim 1, characterized in that, The marking position is determined by the distance between the by-product imprint and the edge of the wafer.

3. The method for cleaning the edge of the wafer buffer layer according to claim 2, characterized in that, The marking position is determined by the distance between the inner circle of the by-product imprint and the edge of the wafer.

4. The method for cleaning the edge of the wafer buffer layer according to claim 1, characterized in that, The first cleaning solution has a contact point on the cleaning line of the wafer, and the distance between the cleaning line and the edge of the wafer is the width of the bevel of the wafer.

5. The method for cleaning the edge of the wafer buffer layer according to claim 3, characterized in that, The second cleaning fluid is sprayed onto the marked location by moving a nozzle, and during the movement of the nozzle, the first cleaning fluid is switched to the second cleaning fluid.

6. The cleaning method for the edge of the wafer buffer layer according to claim 1, characterized in that, The rotational speed of the wafer remains unchanged when the first cleaning solution is sprayed onto the wafer surface and when the second cleaning solution is sprayed onto the marked position.

7. The method for cleaning the edge of the wafer buffer layer according to claim 1, characterized in that, The flow rate of the first cleaning fluid is the same as the flow rate of the second cleaning fluid.

8. The method for cleaning the edge of the wafer buffer layer according to claim 1, characterized in that, The first cleaning solution is any one of DHF, HF, SC1, SC2 or a mixture of HF and HNO3, and the second cleaning solution is any one of DHF, HF, SC1, SC2 or a mixture of HF and HNO3.

9. The method for cleaning the edge of the wafer buffer layer according to claim 8, characterized in that, The first cleaning solution and the second cleaning solution are the same chemical solution.

10. The method for cleaning the edge of the wafer buffer layer according to claim 1, characterized in that, The rinsing solution is deionized water.

11. The method for cleaning the edge of the wafer buffer layer according to claim 5, characterized in that, The contact point of the first cleaning fluid and / or the second cleaning fluid is closer to the edge of the wafer than the orthogonal projection of the nozzle onto the wafer.

12. The method for cleaning the edge of the wafer buffer layer according to claim 11, characterized in that, When the first cleaning solution is sprayed onto the wafer surface and / or the second cleaning solution is sprayed onto the marked position, the nozzle forms an inclined angle of less than 90 degrees with the wafer surface.

13. The method for cleaning the edge of the wafer buffer layer according to claim 1, characterized in that, Before spraying the first cleaning solution onto the wafer surface, the first cleaning solution is pre-sprayed at a location outside the wafer for a preset time.

14. A cleaning device for the edge of a wafer buffer layer, characterized in that, include: A chuck is used to carry and rotate a wafer; The nozzle, connected to an external liquid supply device, is used to spray chemical liquid onto the wafer; The acquisition unit is used to acquire the location of by-product imprints on the wafer surface and record them as the mark location; The controller is configured to: control the nozzle to spray a first cleaning fluid onto the wafer cleaning line to remove the buffer layer at the edge of the wafer; control the acquisition unit to acquire the position of the by-product mark on the wafer surface; control the nozzle to move according to the acquired mark position so that the contact point of the second cleaning fluid sprayed by the nozzle is located at the mark position; and control the nozzle to move to the rinsing position to rinse the surface of the wafer.

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