Wafer cleaning and polishing method
By pre-cleaning the impurities at the crystal edge before semiconductor manufacturing, and using a grinding head to grind and clean the edge area, the problem of wafer scratch defects is solved, achieving the effects of simplifying the process, reducing costs, and shortening the production cycle.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGXIN MEMORY TECH INC
- Filing Date
- 2021-07-28
- Publication Date
- 2026-07-10
AI Technical Summary
In the semiconductor manufacturing process, impurity particles at the crystal edge are easily generated between the main chemical mechanical polishing and photolithography processes, resulting in wafer scratches. Existing photolithography techniques for removing these defects are costly, complex, and extend the production cycle.
Before the main CMP process, the impurities at the crystal edge are pre-cleaned. A grinding head is used to grind the crystal edge area and clean the edge area. Different pressures and cleaning solutions are used to remove impurity particles to avoid damaging the usable chip.
Simplify the process flow, reduce costs, shorten the production cycle, improve wafer yield, and reduce defect sources.
Smart Images
Figure CN115674004B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing, and more particularly to a wafer cleaning and polishing method. Background Technology
[0002] With the rapid development of semiconductor memory technology, the market has placed higher demands on the storage capabilities of semiconductor memory products. For Dynamic Random Access Memory (DRAM), in the current semiconductor process flow, removing edge impurities typically utilizes photolithography, using solvents to dissolve and clean the edge area. However, between the main Chemical-Mechanical Polishing (CMP) process and the photolithography process, there are several thin film (TF) and diffusion (DIFF) processes, which can also easily generate impurities at the edge. These edge impurities form wafer scratches during subsequent CMP polishing. Summary of the Invention
[0003] Therefore, it is necessary to provide a wafer cleaning and polishing method to address the problems mentioned in the background technology above. Before the main CMP process, the wafer edge impurities are pre-cleaned to remove wafer edge impurity particles, reduce wafer defects, and improve wafer yield.
[0004] To address the aforementioned technical problems, the first aspect of this application proposes a wafer cleaning method, comprising:
[0005] A wafer to be cleaned is provided, the wafer to be cleaned comprising a central region, an edge region and a crystal edge region radiating outwards from the center to the edge of the wafer;
[0006] Pre-cleaning the wafer to be cleaned includes:
[0007] A grinding head is provided, the grinding head is placed in the crystal edge region, and the grinding head is controlled to grind the crystal edge region with grinding fluid;
[0008] The grinding head is placed in the edge area, and the grinding head is controlled to clean the edge area with cleaning fluid.
[0009] In one embodiment, the distance from the edge region to the center of the wafer to be cleaned is greater than or equal to 140 mm; the distance from the edge region to the center of the wafer to be cleaned is greater than or equal to 30 mm and less than or equal to 140 mm.
[0010] In one embodiment, the grinding head grinds the crystal edge region using a grinding fluid under a first pressure; the grinding head cleans the edge region using a cleaning fluid under a second pressure; wherein the second pressure is less than the first pressure.
[0011] In one embodiment, the first pressure ranges from 9 to 12 pounds, and the second pressure ranges from 3 to 6 pounds.
[0012] In one embodiment, the cleaning fluid includes deionized water or a cleaning agent.
[0013] In one embodiment, the cleaning agent includes: alkaline cleaning agent, neutral cleaning agent and acidic cleaning agent.
[0014] In one embodiment, controlling the grinding head to clean the edge area with a cleaning solution includes:
[0015] The grinding head is controlled to swing while the cleaning fluid is used to clean the edge area.
[0016] In one embodiment, the grinding head oscillates back and forth between the outer edge of the edge region and the inner edge of the edge region.
[0017] In one embodiment, after placing the grinding head in the edge region and controlling the grinding head to clean the edge region with cleaning fluid, the process further includes:
[0018] Repeat the above steps of pre-cleaning the wafer to be cleaned at least once.
[0019] In one embodiment, the process of pre-cleaning the wafer to be cleaned further includes:
[0020] The pre-cleaned wafer to be cleaned is then cleaned.
[0021] In one embodiment, deionized water is used to clean the pre-cleaned wafer to be cleaned.
[0022] In one embodiment, before pre-cleaning the wafer to be cleaned, the method further includes: placing the wafer to be cleaned on a polishing pad, the polishing pad rotating to drive the wafer to be cleaned to rotate relative to the polishing head; during the rotation of the wafer to be cleaned, the polishing head pre-cleans the wafer to be cleaned.
[0023] In one embodiment, the polishing head rotates during the pre-cleaning process of the wafer to be cleaned, and the rotation direction of the polishing head is opposite to the rotation direction of the wafer to be cleaned.
[0024] A second aspect of this application provides a wafer grinding method, comprising:
[0025] The wafer to be cleaned is cleaned using the wafer cleaning method described above;
[0026] The grinding head is controlled to grind the cleaned wafer using the grinding fluid.
[0027] In one embodiment, controlling the grinding head to grind the cleaned wafer using the grinding fluid includes:
[0028] The cleaned wafer is placed on a grinding disc, which rotates to cause the cleaned wafer to rotate relative to the grinding head.
[0029] The grinding head is controlled to grind the cleaned wafer using the grinding fluid.
[0030] In one embodiment, the grinding head rotates during the grinding process of the cleaned wafer, and the rotation direction of the grinding head is opposite to the rotation direction of the cleaned wafer.
[0031] In the wafer cleaning and polishing method provided in the above embodiments, a pre-cleaning process is performed on the wafer to be cleaned before the main CMP process. Specifically, a polishing head is provided, placed in the edge region, and the polishing head is controlled to polish the edge region with polishing fluid. The polishing head is placed in the edge region, and the polishing head is controlled to clean the edge region with cleaning fluid to remove wafer edge impurity particles without damaging the effective chips on the wafer, reducing the source of wafer defects and improving wafer yield. Compared with the method of removing wafer edge impurity particles by photolithography, the pre-cleaning process is simple, low-cost, and greatly shortens the DRAM production cycle.
[0032] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description
[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.
[0034] Figure 1 This is a schematic flowchart of a wafer cleaning method provided in one embodiment of this application;
[0035] Figure 2This is a top view of the wafer to be cleaned provided in a wafer cleaning method according to an embodiment of this application.
[0036] Figure 3 This is a top view of the structure obtained after placing the provided grinding head in the wafer edge region in a wafer cleaning method provided in one embodiment of this application.
[0037] Figure 4 This is a top view of the structure obtained after placing the provided grinding head in the edge region in a wafer cleaning method provided in one embodiment of this application.
[0038] Figure 5-6 This is a schematic diagram of the structure of a wafer cleaning method provided in one embodiment of this application, in which the wafer to be cleaned is placed on a grinding disk. Figure 5 This is a top view schematic diagram of the structure where the wafer to be cleaned is placed on the grinding pad. Figure 6 A schematic diagram of the side structure for placing the wafer to be cleaned on the grinding pad;
[0039] Figure 7 This is a schematic flowchart of a wafer polishing method provided in one embodiment of this application;
[0040] Figure 8 This is a schematic flowchart of a wafer polishing method provided in another embodiment of this application.
[0041] Figure labeling: 10-wafer, 20-grinding head, 30-grinding disc. Detailed Implementation
[0042] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.
[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0044] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.
[0045] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.
[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.
[0047] Embodiments of the application are described herein with reference to cross-sectional views that serve as schematic diagrams of preferred embodiments (and intermediate structures). Thus, variations from the illustrated shape can be anticipated due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the application should not be limited to the specific shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. The regions shown in the figures are substantially schematic, and their shapes are not intended to show the actual shapes of regions of the device and are not intended to limit the scope of the application.
[0048] Impurity particles left at the wafer edge after TF and DIFF processes can cause wafer scratches during subsequent main CMP processes. Furthermore, flaked flakes remaining in the central wafer area result in incomplete photolithography imaging, preventing the etching pattern from meeting pre-defined targets and further leading to defects such as uneven TF coating or unfilled trenches. Currently, photolithography is used to remove edge impurities by adding a step before the main CMP process. However, this method is not widely adopted due to high mask costs, complex processes, and extended production cycles. Therefore, this application proposes a wafer cleaning and polishing method that pre-cleans edge impurities before the main CMP process. This removes edge impurities without damaging multiple usable chips on the wafer, reducing wafer defects. This method is simple, low-cost, shortens the overall production cycle, and is suitable for pre-processing before patternless processes.
[0049] In one embodiment of this application, such as Figure 1 As shown, a wafer cleaning method is provided, including the following steps:
[0050] Step S10: Provide a wafer to be cleaned, which includes a central region, an edge region, and a crystal edge region that radiate outwards from the center to the edge of the wafer.
[0051] Step S20: Pre-clean the wafer to be cleaned.
[0052] Specifically, step S20: pre-cleaning the wafer to be cleaned, including the following steps:
[0053] Step S21: Provide a grinding head, place the grinding head in the crystal edge region, and control the grinding head to use grinding fluid to grind the crystal edge region;
[0054] Step S22: Place the grinding head in the edge area and control the grinding head to clean the edge area with cleaning fluid.
[0055] In the wafer cleaning method provided in the above embodiments, a pre-cleaning process is performed on the provided wafer to be cleaned before the main CMP process; specifically as follows: a polishing head is provided, the polishing head is placed in the edge region, and the polishing head is controlled to polish the edge region with polishing fluid; the polishing head is placed in the edge region, and the polishing head is controlled to clean the edge region with cleaning fluid to remove wafer edge impurity particles without damaging the effective chips on the wafer, reducing the source of wafer defects, improving wafer yield. Compared with the method of removing wafer edge impurity particles by photolithography, the pre-cleaning process is simple, low-cost, and greatly shortens the DRAM production cycle.
[0056] In one embodiment, such as Figure 2 As shown, the wafer 10 to be cleaned in step S10 includes a central region A, an edge region B, and a wafer edge region C radiating outwards from the center of the wafer 10 to its edge. The distance L1 from the wafer edge region C to the center of the wafer 10 is greater than or equal to 140 mm, for example, 140 mm, 150 mm, 160 mm, 170 mm, or 180 mm, etc. The distance L2 from the edge region B to the center of the wafer 10 is greater than or equal to 30 mm and less than or equal to 140 mm, for example, 30 mm, 40 mm, 60 mm, 100 mm, 120 mm, or 140 mm, etc. The size of the wafer 10 to be cleaned is not fixed, and the distances L1 and L2 from the edge region C to the center of the wafer 10 are also not fixed. This application defines the division of the central region A, edge region B, and wafer edge region C as follows: Figure 2 This example is for illustrative purposes only and is not intended to be limiting. As an example, the pre-cleaning module within the AMAT machine can be used. The program in the pre-cleaning module can be adjusted, and step S20 can be executed to complete the pre-cleaning process of the wafer 10 to be cleaned. It should be noted that the pre-cleaning step for the wafer 10 to be cleaned is not only applicable to pre-processing before the main CMP process, but also to pre-processing before other unpatterned processes, in order to reduce wafer defects and play a crucial role in shortening the overall flow process time.
[0057] In one embodiment, such as Figure 3As shown, the material of the polishing head 20 provided in step S21 may include, but is not limited to, polyester fiber, metal, diamond, or ceramic. The wafer 10 to be cleaned can be fixed, and the polishing head 20 can be controlled to rotate and polish the edge region C; or the polishing head 20 can be fixed, and the wafer 10 to be cleaned can be controlled to rotate counterclockwise or clockwise. The polishing slurry used may include, but is not limited to, a mixture of pure water and silicon dioxide. The polishing rate and rotation speed of the polishing head 20 can be adjusted in real time according to actual conditions. The polishing slurry is provided by a polishing slurry supply device (not shown in the figure), which is connected to the polishing head 20. The polishing slurry flows through the internal pores of the polishing head 20, and finally, the polishing slurry is sprayed from the top of the polishing head 20; alternatively, the polishing slurry can be directly sprayed onto the wafer 10 to be cleaned by the polishing slurry supply device, which can also achieve polishing of the edge region C.
[0058] In one embodiment, such as Figure 4 As shown, the polishing head 20 is placed within the edge region B, and the polishing head 20 is controlled to clean the edge region B using cleaning fluid. It should be noted that the material of the polishing head 20 used for cleaning the edge region B is different from the material of the polishing head 20 used for polishing the wafer region C. When cleaning the wafer 10 to be cleaned, a material with good flexibility, such as polyester fiber, can be used. The cleaning fluid is supplied by a cleaning fluid supply device (not shown in the figure). The cleaning fluid supply device and the polishing head 20 can be connected to each other or not. As shown above, the cleaning fluid supply device is connected to the polishing head 20. The cleaning fluid can flow through the internal pores of the polishing head 20 and be ejected from the top of the polishing head 20; or the cleaning fluid can be directly ejected from the cleaning fluid supply device onto the wafer 10 to be cleaned.
[0059] As an example, the cleaning solution includes deionized water (DIW) or a cleaning agent, including alkaline, neutral, and acidic cleaning agents. For impurity particles left from easy-to-clean thin-film processes, the adhesion of the impurity particles is weak, and the polishing head 20 can be controlled and deionized water can be used to clean the edge area B. For impurity particles left from difficult-to-clean thin-film processes, the adhesion of the impurity particles is weak, and a corresponding cleaning agent is selected according to the film properties, and the polishing head 20 is controlled and the cleaning agent is used to clean the edge area B.
[0060] In one embodiment, the grinding head 20 grinds the crystal edge region C using a grinding slurry under a first pressure; the grinding head 20 then cleans the edge region B using a cleaning fluid under a second pressure. Using both the grinding slurry and the cleaning fluid while simultaneously applying pressure to the grinding head 20 improves the cleaning effect on impurity particles on the crystal edge region C; wherein the second pressure is lower than the first pressure. Specifically, the first pressure ranges from 9 psi to 12 psi, and the second pressure ranges from 3 psi to 6 psi; for example, the first pressure is 9 psi, 10 psi, 10.5 psi, 11 psi, or 12 psi, etc.; and the second pressure is 3 psi, 4 psi, 5 psi, 5.6 psi, or 6 psi, etc.
[0061] In one embodiment, step S21: controlling the grinding head 20 and cleaning the edge area B with cleaning fluid includes the following steps:
[0062] Step S211: Control the grinding head 20 to swing while using cleaning fluid to clean the edge area B.
[0063] As an example, after grinding the crystal edge region C, some residual impurity particles will inevitably enter the edge region B. The grinding head 20 is controlled to oscillate back and forth between the outer edge and the inner edge of the edge region B. While oscillating back and forth between the outer edge and the inner edge of the edge region B, the grinding head 20 itself can also rotate counterclockwise or clockwise to improve the cleaning effect on the edge region B.
[0064] As an example, step S22: after placing the grinding head 20 on the edge region B and controlling the grinding head 20 to clean the edge region B with cleaning fluid, the following steps are also included:
[0065] Step S221: Place the polishing head 20 in the central region A and control the polishing head 20 to clean the central region A with cleaning fluid, thereby achieving complete cleaning of the entire wafer and removing impurity particles from the wafer surface.
[0066] In one embodiment, step S22, after placing the grinding head 20 on the edge region B and controlling the grinding head 20 to clean the edge region B with cleaning fluid, further includes:
[0067] Step S23: Repeat the above steps of pre-cleaning the wafer 10 to be cleaned at least once.
[0068] As an example, after the first pre-cleaning, an inspection machine is used to observe whether there are impurity particles in the edge region B and the crystal edge region C of the wafer 10 to be cleaned; if impurity particles are still present, the above pre-cleaning steps are repeated multiple times until the wafer 10 to be cleaned is completely cleaned.
[0069] In one embodiment, step S20: after pre-cleaning the wafer 10 to be cleaned, the following is also included:
[0070] Step S30: Clean the pre-cleaned wafer 10 to be cleaned.
[0071] Specifically, deionized water is used to perform routine cleaning on all three areas of the pre-cleaned wafer 10. Similarly, the polishing head 20 can be controlled to oscillate while using deionized water to clean the center area A, edge area B, and crystal edge area C of the pre-cleaned wafer 10; alternatively, the cleaning module within the CMP machine can be controlled to clean the pre-cleaned wafer 10. Of course, step S30 is also applicable to routine cleaning before other patternless processes, and this application does not limit it.
[0072] In one embodiment, step S20, prior to pre-cleaning the wafer 10 to be cleaned, further includes the following steps:
[0073] Step S11: Place the wafer 10 to be cleaned on the polishing disk 30. The polishing disk 30 rotates to rotate the wafer 10 relative to the polishing head 20. During the rotation of the wafer 10, the polishing head 20 pre-cleans the wafer 10, such as... Figure 5 and Figure 6 As shown.
[0074] Specifically, the polishing head 20 rotates during the pre-cleaning process of the wafer 10 to be cleaned, and the rotation direction of the polishing head 20 is opposite to the rotation direction of the wafer 10 to be cleaned. As an example, a vacuum wafer chuck (not shown in the figure) is also provided on the contact surface between the polishing disk 30 and the wafer 10 to be cleaned, to stably adsorb the wafer 10 to be cleaned onto the polishing disk 30, so that the polishing disk 30 rotates, causing the wafer 10 to be cleaned to rotate in the same direction and at the same speed. During the pre-cleaning process, both the wafer 10 to be cleaned and the polishing head 20 rotate. If the wafer 10 to be cleaned rotates counterclockwise, the polishing head 20 rotates clockwise; if the wafer 10 to be cleaned rotates in both clockwise and counterclockwise directions, the polishing head 20 rotates counterclockwise. The rotation speed of the wafer 10 to be cleaned and the rotation speed of the polishing head 20 can be the same or different.
[0075] In one embodiment of this application, such as Figure 7 As shown, a wafer grinding method is also proposed, including the following steps:
[0076] Step S40: Clean the wafer 10 to be cleaned using the wafer cleaning method described above;
[0077] Step S50: Control the grinding head 20 to grind the cleaned wafer using grinding fluid.
[0078] As an example, the polishing slurry used for wafer polishing may include, but is not limited to, a mixture of pure water and silica. The polishing slurry used for wafer polishing has a different concentration than the polishing slurry used for pre-cleaning; the silica concentration in the polishing slurry used for wafer polishing is greater than that in the polishing slurry used for pre-cleaning. In step S50, the cleaned wafer is polished. Here, the polishing area is not distinguished; the specific polishing location is specified according to actual needs.
[0079] In one embodiment, such as Figure 8 As shown, step S50: Controlling the polishing head 20 to polish the cleaned wafer using polishing fluid includes the following steps:
[0080] Step S51: Place the cleaned wafer on the polishing disc 30. The polishing disc 30 rotates to rotate the cleaned wafer relative to the polishing head 20. Please refer to the following instructions. Figure 5 and Figure 6 ;
[0081] Step S52: Control the grinding head 20 to grind the cleaned wafer using grinding fluid.
[0082] Specifically, the polishing head 20 rotates during the polishing process of the cleaned wafer, and the rotation direction of the polishing head 20 is opposite to that of the cleaned wafer. During the polishing process, both the cleaned wafer and the polishing head 20 rotate. If the cleaned wafer rotates counterclockwise, the polishing head 20 rotates clockwise; if the cleaned wafer rotates in both clockwise and counterclockwise directions, the polishing head 20 rotates counterclockwise. The rotation speed of the cleaned wafer and the rotation speed of the polishing head 20 can be the same or different.
[0083] As an example, the material of the grinding head 20 during the grinding process of the cleaned wafer can be the same as or different from the material of the grinding head 20 during the grinding process of the pre-cleaned wafer; the material of the grinding head 20 during the grinding process of the cleaned wafer and the material of the grinding head 20 during the grinding process of the pre-cleaned wafer are both different from the material of the grinding head 20 during the cleaning process of the pre-cleaned wafer.
[0084] In one embodiment, after step S52: controlling the grinding head 20 to grind the cleaned wafer with grinding fluid, the method further includes: cleaning the ground wafer with cleaning fluid, wherein the cleaning fluid includes deionized water.
[0085] Please note that the above embodiments are for illustrative purposes only and do not imply any limitation on this application.
[0086] It should be understood that, unless otherwise expressly stated herein, there is no strict order in which the steps are performed, and these steps may be performed in other orders. Moreover, at least some of the steps may include multiple sub-steps or multiple stages, which are not necessarily completed at the same time, but may be performed at different times, and the execution order of these sub-steps or stages is not necessarily sequential, but may be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.
[0087] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0089] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A wafer cleaning method, characterized in that, include: A wafer to be cleaned is provided, the wafer to be cleaned comprising a central region, an edge region and a crystal edge region radiating outwards from the center to the edge of the wafer; Before pre-cleaning the wafer to be cleaned, the process further includes: placing the wafer to be cleaned on a polishing disc, wherein the polishing disc rotates to drive the wafer to be cleaned to rotate relative to the polishing head; Pre-cleaning is performed on the wafer to be cleaned, wherein the grinding head pre-cleans the wafer to be cleaned during the wafer's rotation, including: A grinding head is provided, the grinding head is placed in the crystal edge region, and the grinding head is controlled to grind the crystal edge region with grinding fluid under a first pressure; The grinding head is placed in the edge region, and the grinding head is controlled to clean the edge region with cleaning fluid under a second pressure. The step of controlling the grinding head to clean the edge region with cleaning fluid includes: controlling the grinding head to swing back and forth between the outer edge of the edge region and the inner edge of the edge region. During the pre-cleaning process of the polishing head, the polishing head rotates in the opposite direction to the rotation direction of the wafer to be cleaned, and the second pressure is less than the first pressure.
2. The wafer cleaning method according to claim 1, characterized in that, The distance from the edge region to the center of the wafer to be cleaned is greater than or equal to 140 mm; the distance from the edge region to the center of the wafer to be cleaned is greater than or equal to 30 mm and less than or equal to 140 mm.
3. The wafer cleaning method according to claim 1, characterized in that, The first pressure ranges from 9 to 12 pounds, and the second pressure ranges from 3 to 6 pounds.
4. The wafer cleaning method according to claim 1, characterized in that, The cleaning solution includes deionized water or a cleaning agent.
5. The wafer cleaning method according to claim 4, characterized in that, The cleaning agents include: alkaline cleaning agents, neutral cleaning agents, and acidic cleaning agents.
6. The wafer cleaning method according to claim 1, characterized in that, After placing the polishing head in the edge region and controlling the polishing head to clean the edge region with cleaning fluid, the process further includes repeating the above-described pre-cleaning steps for the wafer to be cleaned at least once.
7. The wafer cleaning method according to claim 1, characterized in that, The process of pre-cleaning the wafer to be cleaned further includes cleaning the pre-cleaned wafer.
8. The wafer cleaning method according to claim 7, characterized in that, The pre-cleaned wafer to be cleaned is cleaned with deionized water.
9. A wafer grinding method, characterized in that, include: The wafer to be cleaned is cleaned using the wafer cleaning method as described in any one of claims 1 to 8; The grinding head is controlled to grind the cleaned wafer using the grinding fluid.
10. The wafer grinding method according to claim 9, characterized in that, Controlling the grinding head to grind the cleaned wafer using the grinding fluid includes: The cleaned wafer is placed on a polishing disc, which rotates to rotate the cleaned wafer relative to the polishing head; the polishing head is controlled to polish the cleaned wafer using the polishing fluid.
11. The wafer grinding method according to claim 10, characterized in that, The grinding head rotates during the grinding process of the cleaned wafer, and the rotation direction of the grinding head is opposite to the rotation direction of the cleaned wafer.