Clamping assembly, wafer machining method and metal process equipment

Abstract

The invention relates to a clamping assembly, a wafer machining method and metal process equipment. The clamping assembly comprises an upper clamp, the upper clamp comprises an upper clamp top and a clamping ring extending downwards from the bottom of the upper clamp top, and the cross section area of the bottom of the clamping ring is smaller than the cross section area of the connecting position of the top of the clamping ring and the top of the upper clamp; wherein the clamping ring is in contact with the upper surface, exposed out of the edge of the substrate, of the wafer so as to clamp the wafer, and the clamping assembly is not in contact with a polycrystalline silicon layer of the wafer when clamping the wafer. According to the clamping assembly, the contact area between the clamping assembly and the upper surface of the wafer can be reduced, so that particle sources generated by friction between the clamping assembly and the wafer are reduced, meanwhile, due to the fact that the clamping ring makes direct contact with the compact substrate, compared with clamping of a polycrystalline silicon layer, the generated particle sources can be further reduced, and the production efficiency is improved. Therefore, in-film particle defects in the metal film layer are reduced, and the yield of the semiconductor device is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and particularly to a clamping component, a wafer processing method, and a metal processing device. Background Art

[0002] In the semiconductor metal deposition manufacturing process, metal deposition is mainly divided into two categories: evaporation and sputtering. Since the heating source structure of the equipment used in the evaporation process is simple, low in cost, and convenient to operate, it is widely used in MEMS (Micro Electromechanical System) devices with a relatively large line width. However, when the existing metal processing equipment uses the metal evaporation process for metal deposition, there will be more in-film particle defects in the formed metal film layer, resulting in a low yield of semiconductor devices. Summary of the Invention

[0003] Based on this, in view of the above technical problems, it is necessary to provide a clamping component, a wafer processing method, and a metal processing device that can reduce in-film particle defects in the metal film layer.

[0004] In a first aspect, the present application proposes a clamping component applied to the metal process. The clamping component is used to clamp a wafer. The clamping component includes: an upper fixture, the upper fixture includes an upper fixture top, and a clamping ring extending downward from the bottom of the upper fixture top. The cross-sectional area of the bottom of the clamping ring is smaller than the cross-sectional area of the connection position between the top of the clamping ring and the upper fixture top. Wherein, the clamping ring contacts the upper surface of the exposed substrate edge of the wafer to clamp the wafer, and the clamping component does not contact the polysilicon layer of the wafer when clamping the wafer.

[0005] In one embodiment, the length of the top of the clamping ring in its diameter direction is not greater than the distance between the edge of the substrate and the edge of the polysilicon layer.

[0006] In one embodiment, the upper fixture top includes: a connecting portion and an annular structure. The connecting portion is perpendicular to the annular structure, and the clamping ring is connected to the bottom of the annular structure.

[0007] In one embodiment, the clamping ring is a wedge-shaped ring, and the longitudinal cross-section of the wedge-shaped ring decreases in the direction close to the connecting portion.

[0008] In one embodiment, the longitudinal cross-section of the wedge-shaped ring is a right triangle, and the right side of the right triangle is connected to the bottom of the annular structure.

[0009] In one embodiment, the maximum ring width of the annular structure is greater than the maximum ring width of the clamping ring.

[0010] In one embodiment, the distance between the bottom and the top of the clamping ring is greater than or equal to 0.2 mm.

[0011] In a second aspect, the present application further provides a method for processing a wafer. The clamping assembly described in the first aspect embodiment is used to clamp the wafer and perform a metal process to form a metal layer.

[0012] In one embodiment, the method further includes: performing polysilicon lithography on the wafer, where a substrate and a polysilicon layer on the substrate are formed on the wafer; performing polysilicon etching on the wafer, and the polysilicon etching removes a part of the edge of the polysilicon layer so that the upper surface of the edge of the substrate is exposed; wherein, the distance between the edge of the substrate and the edge of the polysilicon layer is not greater than the distance between the edge of the substrate and the edge of the metal layer.

[0013] In a third aspect, the present application further provides a metal processing device, including the clamping assembly described in the first aspect embodiment.

[0014] The above-mentioned clamping assembly, the method for processing a wafer, and the metal processing device clamp the wafer by providing a downwardly extending clamping ring at the bottom of the top of the upper fixture and making the clamping ring contact the upper surface of the exposed edge of the substrate. At the same time, when clamping the wafer, the clamping assembly does not contact the polysilicon layer. By the clamping assembly provided in the present application, the contact area between the clamping assembly and the upper surface of the wafer can be reduced, thereby reducing the particle source generated by the friction between the clamping assembly and the wafer. At the same time, since the clamping ring directly contacts the relatively dense substrate, compared with clamping the polysilicon layer, the generated particle source can be further reduced, thereby reducing the in-film particle defects in the metal film layer and improving the yield of semiconductor devices. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a schematic structural diagram of a clamping assembly in an embodiment;

[0017] Figure 2 For Figure 1 The partial enlarged view in the embodiment;

[0018] Figure 3 It is a schematic diagram of the polysilicon layer trimming size in an embodiment;

[0019] Figure 4 Schematic diagram of the connection part and the ring structure in an embodiment;

[0020] Figure 5 Schematic diagram of the trimming size of the metal layer in an embodiment;

[0021] Figure 6 Schematic diagram of the number of defects in the metal layer film in an embodiment;

[0022] Figure 7 Flow chart of the processing method of the wafer in an embodiment;

[0023] Explanation of reference numerals:

[0024] Top of the upper fixture 110, clamping ring 120, substrate 130, back fixture 140, connection part 111, ring structure 112, wafer 200, substrate 210, polysilicon layer 220, metal layer 230. Detailed implementation manners

[0025] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. Embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0027] In this application, unless otherwise clearly specified and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

[0028] In this application, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0029] As used herein, the singular forms "a", "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprising", "including" or "having" etc. specify the presence of the stated features, wholes, steps, operations, components, parts or combinations thereof, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the related listed items.

[0030] As described in the background art, in the prior art during the metal process, there are problems of more defects of particles in the film. Through research by the inventor, it is found that the reason for this problem is that the contact area between the clamping component of the metal deposition equipment and the front surface of the wafer to be deposited is large, and the clamping component generally clamps on the deposited polysilicon layer. Under the action of the friction between the clamping component and the polysilicon, it is easy to generate particle sources, and then more defects of particles in the film will be formed during the metal process, resulting in a low yield of semiconductor devices.

[0031] For the above reasons, this application provides a clamping component, a processing method of a wafer and a metal process equipment, which can effectively reduce the defects of particles in the film during the metal process.

[0032] In one embodiment, as Figure 1 and Figure 2 shown, a clamping component is provided, which is applied to the metal process. The clamping component is used to clamp the wafer 200. The clamping component includes: an upper fixture, the upper fixture includes an upper fixture top 110, and a clamping ring 120 extending downward from the bottom of the upper fixture top 110. The cross-sectional area of the bottom of the clamping ring 120 is smaller than the cross-sectional area of the connection position between the top of the clamping ring 120 and the upper fixture top 110; wherein, the clamping ring 120 contacts the upper surface of the edge of the exposed substrate 210 of the wafer 200 to clamp the wafer 200, and the clamping component does not contact the polysilicon layer 220 of the wafer 200 when clamping the wafer 200.

[0033] Specifically, the clamping assembly of the embodiment of the present application is used to clamp a wafer 200 that needs to undergo a metal process. The wafer 200 includes a substrate 210 and a polysilicon layer 220. After the metal process, a metal layer 230 is formed on the polysilicon layer 220. In order to allow the clamping ring 120 to contact the substrate 210 of the wafer 200, the polysilicon layer 220 is subjected to an edge removal process so that the polysilicon layer 220 does not cover the edge position of the substrate 210. When the clamping assembly clamps the wafer 200, the clamping ring 120 contacts the upper surface of the edge of the substrate 210 exposed by the wafer 200 to clamp the wafer 200. When clamping the wafer 200, the clamping assembly will not contact the polysilicon layer 220 of the wafer 200, that is, the clamping ring 120 or the top 110 of the upper fixture will not contact the polysilicon layer 220.

[0034] The clamping assembly includes: an upper clamp, the upper clamp includes an upper clamp top 110, and a clamping ring 120 extending downward from the bottom of the upper clamp top 110. The clamping ring 120 is arranged in a ring shape, and is used to increase the contact area with the substrate 210 of the wafer 200, so as to completely clamp the wafer 200 and improve the stability during clamping. Since the clamping ring 120 is formed by extending downward from the bottom of the upper clamp top 110, the upper clamp top 110 is also arranged in a ring shape. When the clamping assembly clamps the wafer 200, the bottom of the clamping ring 120 is a side facing the wafer 200, which is used to contact the wafer 200, and the top of the clamping ring 120 is the other side away from the wafer 200, which is used to connect with the upper clamp top 110. In this embodiment, the cross-sectional area of ​​the bottom of the clamping ring 120 is set to be smaller than the cross-sectional area of ​​the connection position between the top of the clamping ring 120 and the top 110 of the upper fixture. The cross-sectional area is a plane parallel to the surface of the wafer 200, that is, the cross-sectional area of ​​the side of the clamping ring 120 close to the wafer 200 is smaller than the cross-sectional area of ​​the other side of the clamping ring 120 away from the wafer 200, so that the connection between the clamping ring 120 and the top 110 of the upper fixture is more stable.

[0035] In one embodiment, Figure 1 As shown, the clamping assembly further includes: a base 130 and a back clamp 140 for clamping the base 130. The base 130 is used to place the wafer 200. The upper clamp and the back clamp 140 form a clamping space in the clamping state. The clamping space is used to place the base 130 and the wafer 200. The upper clamp and the back clamp 140 fix the base 130 and the wafer 200 together in the clamping state. In some other embodiments, the back clamp 140 can also be fixedly connected to the base 130, and the back clamp 140 can drive the base 130 to move when moving.

[0036] In one embodiment, Figure 3As shown, the length of the top of the clamping ring 120 along its diameter direction is not greater than the distance between the edge of the substrate 210 and the edge of the polysilicon layer 220. Specifically, since the clamping ring 120 is annular, its diameter direction is the diameter direction of the ring, and the length of the top of the clamping ring 120 along its diameter direction is also the length of the side of the clamping ring 120 away from the wafer 200 along its diameter direction, that is, Figure 3 The distance between the edge of the substrate 210 and the edge of the polysilicon layer 220 is the edge removal size of the polysilicon layer 220, that is, Figure 3 By setting W≤A, the clamping ring 120 can be prevented from contacting the polysilicon layer 220 or just contacting the polysilicon layer 220 when clamping the wafer 200, and the clamping ring 120 can be prevented from applying pressure to the edge of the polysilicon layer 220, thereby reducing the particle source generated by friction of the polysilicon layer 220.

[0037] In one embodiment, Figure 4 As shown, the top 110 of the upper clamp includes: a connecting portion 111 and an annular structure 112, the connecting portion 111 is perpendicular to the annular structure 112, and the clamping ring 120 is connected to the bottom of the annular structure 112. Specifically, the top 110 of the upper clamp in this embodiment includes a connecting portion 111 and an annular structure 112, the connecting portion 111 is fixedly connected to the outer side of the annular structure 112, the outer side of the annular structure 112 is a side away from the center of its annular circle, and the connecting portion 111 is vertically arranged with the annular structure 112. The connecting portion 111 can be arranged in an annular shape or composed of a plurality of connecting rods to fix the annular structure 112. The top of the clamping ring 120 is connected to the bottom of the annular structure 112, and the clamping ring 120 is in contact with the connecting portion 111, so that an angle is formed between the clamping ring 120 and the connecting portion 111. In some other embodiments, the clamping ring 120 can also be spaced a certain distance from the connecting portion 111.

[0038] In one embodiment, the clamping ring 120 is a wedge-shaped ring, and the longitudinal section of the wedge-shaped ring decreases in the direction close to the connecting portion 111. Specifically, in this embodiment, the clamping ring 120 is set as a wedge-shaped ring, and the wedge is a shape similar to an inverted triangle, and the wedge-shaped ring is a ring corresponding thereto. The cross-sectional area of ​​the bottom of the wedge-shaped ring is smaller than the cross-sectional area of ​​the top thereof, and the contact position between the wedge-shaped ring and the upper surface of the edge of the substrate 210 is determined by the shape of the longitudinal section of the wedge-shaped ring, which can be set according to the clamping needs of the wafer 200. The longitudinal section of the wedge-shaped ring is a plane perpendicular to the surface of the wafer 200 and passing through the center of the wedge-shaped ring. The longitudinal section of the wedge-shaped ring decreases in the direction close to the connecting portion 111. Therefore, when the clamping assembly clamps the wafer 200, the space between the wedge-shaped ring and the wafer 200 increases in the direction close to the connecting portion 111.

[0039] In one embodiment, the longitudinal section of the wedge ring is a right triangle, and the right angle side of the right triangle is connected to the bottom of the ring structure 112. Specifically, in this embodiment, the long right angle side or the short right angle side of the right triangle can be connected to the bottom of the ring structure 112. In order to increase the contact area between the wedge ring and the wafer 200, the long right angle side of the right triangle can be connected to the bottom of the ring structure 112, so that the larger acute angle contacts the wafer 200.

[0040] In one embodiment, the maximum ring width of the annular structure 112 is greater than the maximum ring width of the clamping ring 120. Specifically, in this embodiment, the maximum ring width of the annular structure 112 is set to be greater than the maximum ring width of the clamping ring 120, that is, the projection surface of the annular structure 112 in the longitudinal direction will completely cover the projection surface of the clamping ring 120 in the longitudinal direction, and the longitudinal direction refers to the direction perpendicular to the surface of the wafer 200, that is, the direction from the polysilicon layer 220 to the substrate 210. Figure 4 As shown, when the longitudinal section of the clamping ring 120 is set to a right triangle and the longitudinal section of the annular structure 112 is set to a rectangle, the maximum ring width of the clamping ring 120 is the right angle side connected to the annular structure 112 in the right triangle, and the maximum ring width of the annular structure 112 is the length of the side connected to the right triangle. By setting the maximum ring width of the annular structure 112 to be greater than the maximum ring width of the clamping ring 120, the annular structure 112 is made to extend beyond the clamping ring 120. It can be understood that the extended annular structure 112 does not contact the polysilicon layer 220. In some other embodiments, the maximum ring width of the annular structure 112 may also be less than or equal to the maximum ring width of the clamping ring 120.

[0041] In one embodiment, the distance between the bottom of the clamping ring 120 and the top of the clamping ring 120 is greater than or equal to 0.2 mm. Figure 5 As shown, the distance H between the horizontal plane where the bottom of the clamping ring 120 in this embodiment is located and the horizontal plane where the top of the clamping ring 120 is located is greater than or equal to 0.2 mm. When it is greater than or equal to 0.2 mm, the height requirements of the clamping ring 120 of most devices can be met.

[0042] Specific examples, such as Figure 6 , which is a schematic diagram of the number of intra-film defects of the metal layer 230 obtained by using the clamping assembly of the embodiment of the present application and not using the clamping assembly of the embodiment of the present application, it can be seen from the figure that under the original design (not using the clamping assembly of the embodiment of the present application), the overall level of the number of intra-film defects of the metal layer 230 is high, and under the new design (using the clamping assembly of the embodiment of the present application), the number of intra-film defects of the metal layer 230 is at a low level. Therefore, when the clamping assembly of the embodiment of the present application is used, the intra-film particle defects in the metal layer 230 can be reduced, thereby improving the yield of the semiconductor device.

[0043] It should be noted that the top and bottom described in the above embodiment are the relative position relationship of the clamping assembly under normal use.

[0044] In one embodiment, the present application also proposes a method for processing a wafer, using the clamping assembly in the above embodiment to clamp the wafer 200 and perform metal processing to form a metal layer 230. Since the clamping assembly does not contact the polysilicon layer 220 of the wafer 200 when clamping the wafer 200, but directly contacts the denser substrate 210, compared with clamping the polysilicon layer 220, the particle source generated can be reduced. And the clamping ring 120 directly contacts the upper surface of the edge of the substrate 210 exposed by the wafer 200, which can reduce the contact area between the clamping ring 120 and the upper surface of the wafer 200, thereby further reducing the particle source generated by the friction between the clamping assembly and the wafer 200.

[0045] In one embodiment, Figure 7 As shown, the wafer processing method includes but is not limited to the following steps:

[0046] Step S310, polysilicon photolithography. Specifically, firstly, polysilicon photolithography is performed on the wafer 200, and the polysilicon photolithography forms a photoresist layer with a mask pattern on the polysilicon layer 220 through an exposure and development process. It is understandable that before the polysilicon photolithography is performed on the wafer 200, polysilicon deposition is first performed on the substrate 210 of the wafer 200, and the wafer 200 is a wafer 200 having a substrate 210 and a polysilicon layer 220 on the substrate 210 after the polysilicon deposition process is performed on the substrate 210.

[0047] Step S320, polysilicon etching. Specifically, after polysilicon photolithography, polysilicon etching is performed on the wafer 200, and the polysilicon etching removes a portion of the edge of the polysilicon layer 220, thereby exposing the upper surface of the edge of the substrate 210. It is understandable that when performing polysilicon photolithography, the edge removal size of the polysilicon layer 220 can be selected, and the position of the edge of the polysilicon layer 220 is removed by a preset range through polysilicon etching, thereby exposing the upper surface of the edge of the substrate 210.

[0048] Step S330, metal photolithography. Specifically, after the polysilicon etching is completed, metal photolithography is performed on the metal layer 230 to be formed. By performing metal deposition on the photoresist layer formed by the metal photolithography, a metal layer 230 with a specific pattern and connection structure can be formed. Metal photolithography can determine the position and structure of the metal layer 230 to be formed by forming a photoresist layer on the polysilicon layer 220. For example, the edge removal size of the pre-formed metal layer 230 can be selected, and its specific position and structure size can be set according to the design function.

[0049] Step S340, metal deposition. Specifically, after the photoresist layer is formed by metal lithography, the wafer 200 is clamped by a clamping assembly and then a metal process is performed, i.e., metal deposition. It is understandable that before the metal process, a pre-cleaning process may be performed to reduce the film defects formed during the deposition process. After the metal deposition is completed, a degumming process is performed to form a deposited metal layer 230. Finally, a defect inspection is performed to determine whether the film particle defects in the metal layer 230 meet the process requirements. Figure 5 As shown, after metal deposition, the distance A between the edge of the substrate 210 and the edge of the polysilicon layer 220 is not greater than the distance B between the edge of the substrate 210 and the edge of the metal layer 230. The present application prevents the metal layer 230 from contacting the substrate 210 by setting A≤B.

[0050] The clamping assembly of the metal deposition equipment is used to clamp and fix the wafer 200. Figure 1 and Figure 2 As shown, the clamping assembly includes an upper clamp, the upper clamp includes an upper clamp top 110, and a clamping ring 120 extending downward from the bottom of the upper clamp top 110, the cross-sectional area of ​​the bottom of the clamping ring 120 is smaller than the cross-sectional area of ​​the connection position between the top of the clamping ring 120 and the upper clamp top 110; wherein the clamping ring 120 contacts the upper surface of the edge of the substrate 210 exposed by the wafer 200 to clamp the wafer 200, and the clamping assembly does not contact the polysilicon layer 220 of the wafer 200 when clamping the wafer 200.

[0051] In the above-mentioned processing method of the wafer, in the metal process, a downwardly extending clamping ring 120 is provided at the bottom of the top 110 of the upper clamp, and the clamping ring 120 is made to contact the upper surface of the exposed edge of the substrate 210, thereby clamping the wafer 200. At the same time, when clamping the wafer 200, the clamping component does not contact the polysilicon layer 220. Through the clamping component provided in the present application, the contact area between the clamping component and the upper surface of the wafer 200 can be reduced, thereby reducing the particle source generated by the friction between the clamping component and the wafer 200. At the same time, since the clamping ring 120 is directly in contact with the relatively dense substrate 210, compared with clamping the polysilicon layer 220, the particle source generated can be further reduced, thereby reducing the intra-film particle defects in the metal layer 230 and improving the yield of the semiconductor device.

[0052] In one embodiment, the present application also proposes a metal processing equipment, including the clamping assembly described in the above embodiment. The above metal processing equipment is provided with a downwardly extending clamping ring 120 at the bottom of the top 110 of the upper clamp, and the clamping ring 120 is in contact with the upper surface of the exposed edge of the substrate 210, so as to clamp the wafer 200. At the same time, when clamping the wafer 200, the clamping assembly does not contact the polysilicon layer 220. Through the clamping assembly provided in the present application, the contact area between the clamping assembly and the upper surface of the wafer 200 can be reduced, thereby reducing the particle source generated by the friction between the clamping assembly and the wafer 200. At the same time, since the clamping ring 120 is in direct contact with the denser substrate 210, compared with clamping the polysilicon layer 220, the particle source generated can be further reduced, thereby reducing the intra-film particle defects in the metal layer 230 and improving the yield of the semiconductor device.

[0053] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0054] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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.

[0055] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A clamping assembly, characterized in that, applied in metal processing, the clamping assembly is used to clamp a wafer, and the clamping assembly includes: an upper fixture, the upper fixture includes an upper fixture top, and a clamping ring extending downward from the bottom of the upper fixture top, and the cross-sectional area of the bottom of the clamping ring is smaller than the cross-sectional area of the connection position between the top of the clamping ring and the upper fixture top; wherein, the clamping ring contacts the upper surface of the exposed substrate edge of the wafer to clamp the wafer, and the clamping assembly does not contact the polysilicon layer of the wafer when clamping the wafer.

2. The clamping assembly according to claim 1, characterized in that, the length of the top of the clamping ring in the diameter direction thereof is not greater than the distance between the edge of the substrate and the edge of the polysilicon layer.

3. The clamping assembly according to claim 1, characterized in that, the upper fixture top includes: a connecting portion and an annular structure, the connecting portion is perpendicular to the annular structure, and the clamping ring is connected to the bottom of the annular structure.

4. The clamping assembly according to claim 3, characterized in that, the clamping ring is a wedge-shaped ring, and the longitudinal section of the wedge-shaped ring decreases in the direction close to the connecting portion.

5. The clamping assembly according to claim 4, characterized in that, the longitudinal section of the wedge-shaped ring is a right triangle, and the right-angled side of the right triangle is connected to the bottom of the annular structure.

6. The clamping assembly according to claim 3, characterized in that, the maximum ring width of the annular structure is greater than the maximum ring width of the clamping ring.

7. The clamping assembly according to any one of claims 1 to 6, characterized in that, the distance between the bottom and the top of the clamping ring is greater than or equal to 0.2 mm.

8. A method for processing a wafer, characterized in that, clamping the wafer by using the clamping assembly according to any one of claims 1 to 7 and performing metal processing to form a metal layer.

9. The processing method according to claim 8, characterized in that, the method further includes: performing polysilicon lithography on the wafer, a substrate and a polysilicon layer on the substrate being formed on the wafer; performing polysilicon etching on the wafer, and the polysilicon etching removes a part of the edge of the polysilicon layer so that the upper surface of the substrate edge is exposed; wherein, the distance between the edge of the substrate and the edge of the polysilicon layer is not greater than the distance between the edge of the substrate and the edge of the metal layer.

10. A metal processing device, characterized in that, including the clamping assembly according to any one of claims 1 to 7.

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