Wafer retaining ring
By integrating multiple independent sub-dressing discs into the wafer retaining ring, the problems of retaining ring wear and polishing pad dressing disc complexity are solved, achieving the effects of reducing costs and improving maintenance efficiency.
Patent Information
- Application Number
- CN202422320179.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2026-01-02
- Estimated Expiration
- 2034-09-23
AI Technical Summary
Existing wafer retaining rings suffer severe wear during the polishing process, requiring periodic replacement and increasing the cost of chemical mechanical polishing. Furthermore, the existing polishing pad dressing discs have complex mechanical structures and high maintenance costs.
Design a wafer retaining ring that integrates multiple independent sub-trimming discs. There are gaps and recessed grooves between adjacent sub-trimming discs. Each sub-trimming disc is detachably connected to the main body and fixed by bolts or snap-fit. The trimming discs contact the polishing pad to reduce wear on the retaining ring.
It reduces component loss rate, improves maintenance efficiency and structural disassembly flexibility, simplifies the maintenance process, and reduces maintenance costs.
Smart Images
Figure CN223749359U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of mechanical grinding, in particular to a wafer retaining ring. BACKGROUND
[0002] The retaining ring in the chemical mechanical polishing device is a component for fixing the wafer in the chemical mechanical polishing process, and the polishing pad outside the wafer edge and the corresponding polishing pad on the lower side of the wafer are pressed flat to the same height, so that the over-grinding problem in the polishing process is solved. At present, when the equipment is maintained or the polishing head is maintained, the retaining ring will gradually thin out with the increase of the grinding time. Since the retaining ring needs to be replaced regularly due to wear, the cost of the chemical mechanical polishing process is relatively high, and the mechanical structure of the existing trimming disc for trimming the polishing pad is complex, and also needs to be replaced regularly with the increase of the grinding time, further increasing the maintenance cost.
[0003] Therefore, how to provide a wafer retaining ring that reduces grinding wear and improves maintenance efficiency is a technical problem that technicians in the field urgently need to solve. SUMMARY
[0004] Therefore, the utility model discloses a wafer retaining ring, which solves the problem that the wafer retaining ring in the prior art gradually thins out with the increase of the grinding time, needs to be replaced regularly, results in relatively high cost of the chemical mechanical polishing process, and the mechanical structure of the existing trimming disc for trimming the polishing pad is complex, also needs to be replaced regularly, and further increases the maintenance cost.
[0005] To solve the above technical problems, the utility model provides a wafer retaining ring, which comprises:
[0006] A wafer retaining ring main body and a trimming disc piece arranged on the surface of the wafer retaining ring main body close to the grinding side;
[0007] The trimming disc piece comprises a plurality of sub-trimming disc pieces independently arranged along the circumference of the surface of the wafer retaining ring main body, and there is a gap between adjacent sub-trimming disc pieces to form a recessed groove at least between the adjacent sub-trimming disc pieces;
[0008] Each sub-trimming disc piece is detachably connected with the wafer retaining ring main body.
[0009] Optionally, each sub-trimming disc piece comprises a protruding part matched with the wafer retaining ring main body.
[0010] Optionally, the protruding part is a bolt;
[0011] The wafer retaining ring main body is provided with a bolt mounting hole corresponding to the bolt;
[0012] The sub-truing disc is connected with the wafer holding ring body through the bolt.
[0013] Optionally, the bolt and the sub-truing disc are integrally formed.
[0014] Optionally, each sub-truing disc is detachably connected with the wafer holding ring body through the clamping component.
[0015] Optionally, the wafer holding ring body and the surface, to which the sub-truing disc is connected, are correspondingly provided with a plurality of protruding structures.
[0016] The recessed grooves are formed between adjacent protruding structures, and the recessed grooves formed between adjacent protruding structures are correspondingly arranged with the recessed grooves formed between adjacent sub-truing discs.
[0017] Optionally, the protruding structures and the sub-truing disc coincide in the direction in which the wafer holding ring body points to the sub-truing disc.
[0018] Optionally, each sub-truing disc is detachably connected with the wafer holding ring body through the bolt connection and the clamping connection.
[0019] Optionally, the recessed grooves form an included angle with the radius of the wafer holding ring body.
[0020] Optionally, at least the side, which is away from the wafer holding ring body, of the sub-truing disc is provided with a diamond sub-truing disc part.
[0021] It can be seen that the wafer holding ring provided by the utility model comprises a wafer holding ring body and a truing disc arranged on the surface of the wafer holding ring body close to the grinding side, the truing disc comprises a plurality of sub-truing discs independently arranged along the surface of the wafer holding ring body in the circumferential direction, and there is a spacing between adjacent sub-truing discs to form recessed grooves between at least adjacent sub-truing discs, and each sub-truing disc is detachably connected with the wafer holding ring body. The utility model integrates the truing disc in the wafer holding ring, which can contact the truing disc with the polishing pad to avoid damaging the wafer holding ring during grinding, reduce the device loss rate, and additionally set the truing disc as a plurality of independently arranged sub-truing discs, and set each sub-truing disc to be detachably connected with the wafer holding ring body, so that the corresponding sub-truing disc can be replaced during maintenance, improve the structure disassembly flexibility, and further improve the structure maintenance efficiency. BRIEF DESCRIPTION OF DRAWINGS
[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are only a part of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0023] Figure 1 A structure diagram of a wafer retaining ring provided by the embodiment of the present application is shown in the figure.
[0024] Figure 2 A structure diagram of a wafer retaining ring provided by the embodiment of the present application is shown in the figure.
[0025] Figure 3 A structure diagram of a wafer retaining ring provided by the embodiment of the present application is shown in the figure.
[0026] Figure 4 A structure diagram of a wafer retaining ring provided by the embodiment of the present application is shown in the figure.
[0027] Figure 5 A structure diagram of a wafer retaining ring provided by the embodiment of the present application is shown in the figure.
[0028] Figure 6 A structure diagram of a wafer retaining ring provided by the embodiment of the present application is shown in the figure.
[0029] Figures 1 to 6 In the figure, the following marks are explained:
[0030] 1-wafer, 2-existing wafer retaining ring, 3-polishing head, 4-existing trimmer, 5-abrasive liquid spraying component, 6-polishing pad;
[0031] 10-wafer retaining ring main body, 11-bolt mounting hole;
[0032] 20-sub-trimmer disc, 21-bolt. DETAILED DESCRIPTION
[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0034] Embodiment 1:
[0035] Please refer to Figure 1 , Figure 1A structure schematic diagram of a wafer retaining ring provided by the embodiment of the utility model. The wafer retaining ring can include
[0036] Wafer retaining ring main body 10, and the trimming disc is arranged on the surface of wafer retaining ring main body 10 close to the grinding side;
[0037] The trimming disc includes a plurality of sub trimming discs 20 independently arranged along the surface of wafer retaining ring main body 10 in the circumference, and there is a spacing between adjacent sub trimming discs 20, so as to form a recessed groove at least between adjacent sub trimming discs 20;
[0038] Each sub trimming disc 20 is detachably connected with wafer retaining ring main body 10.
[0039] It needs to be pointed out that the wafer retaining ring main body 10 in the embodiment can refer to the existing wafer retaining ring 2, and the existing wafer retaining ring 2 can refer to Figure 2 And Figure 3 , Figure 2 It is a structure schematic diagram of an existing wafer retaining ring, Figure 3 It is a structure schematic diagram of an existing polishing head with wafer retaining ring. In the embodiment, the surface of wafer retaining ring main body 10 close to the grinding side, the surface of wafer retaining ring main body 10 close to the polishing disc and polishing pad 6 side during grinding processing, and the trimming disc is arranged on the surface of wafer retaining ring main body 10 close to the grinding side in the application, the trimming disc contacts the polishing pad 6 during grinding, without wasting the wafer retaining ring, avoiding grinding wear of the wafer retaining ring, and the trimming disc as a wear part itself needs to contact the polishing pad 6, so that the overall wear of the components is reduced, and the trimming disc and the wafer retaining ring are integrated in the embodiment, without additional mechanical arm connection trimming disc, reducing the complexity of the structure. In addition, it needs to be pointed out that the polishing device with the wafer retaining ring and the trimming disc arranged separately in the embodiment can refer to Figure 4 And Figure 5 , Figure 4 It is a top view structure schematic diagram of an existing polishing device, Figure 5 It is a side view structure schematic diagram of an existing polishing device.
[0040] Further, in the embodiment, the trimming disc is composed of multiple independent sub-trimming discs 20, and each sub-trimming disc 20 is detachably connected with the wafer holding ring main body 10. When maintenance is needed, only the specified sub-trimming disc 20 that needs maintenance is detached and maintained, thereby improving the flexibility of detaching the trimming disc and the convenience of maintaining the trimming disc. In an actual scenario, when only part of the sub-trimming discs 20 are severely worn and need maintenance, only the corresponding sub-trimming disc 20 needs to be detached and maintained. In addition, it is further explained that, in the embodiment, the multiple sub-trimming discs 20 are arranged along the surface of the wafer holding ring main body 10 close to the grinding side to form a ring-shaped surface, that is, the sub-trimming discs 20 are arranged around the center of the wafer holding ring main body 10 in the circumferential direction of the surface of the wafer holding ring main body 10, and each sub-trimming disc 20 is independently arranged, and there is a spacing between adjacent sub-trimming discs 20, which can serve as a flow channel for spraying the grinding liquid to the wafer 1 in the wafer holding ring, that is, the recessed groove.
[0041] In the embodiment, the detachable connection between the sub-trimming disc 20 and the wafer holding ring main body 10 can be set according to the actual working condition. In addition, in the embodiment, the specific size of the spacing between the adjacent sub-trimming discs 20 is not limited, as long as the grinding liquid can act on the wafer 1 in the wafer holding ring through the recessed groove.
[0042] Further, in order to ensure the connection between the sub-trimming disc 20 and the wafer holding ring main body 10, each sub-trimming disc 20 can include a protruding part matched with the wafer holding ring main body 10.
[0043] It is necessary to be explained that, in the embodiment, each sub-trimming disc 20 includes a protruding part, and the protruding part is used to connect with the wafer holding ring main body 10, thereby ensuring the stability of the connection between the sub-trimming disc 20 and the wafer holding ring main body 10.
[0044] However, the embodiment does not limit the specific position of the protruding part in the sub-trimming disc 20. In order to simplify the structure, the protruding part can be located on the surface of the sub-trimming disc 20 close to the wafer holding ring main body 10. The embodiment does not limit the specific structure of the protruding part, as long as the sub-trimming disc 20 and the wafer holding ring main body 10 can be stably connected and can be detached after connection. It can be understood that the wafer holding ring main body 10 can be correspondingly provided with a recessed part matched with the protruding part, or the wafer holding ring main body 10 can be correspondingly provided with a wafer holding ring protruding part corresponding to the protruding part in the sub-trimming disc 20, and the two are fixed by a fixing part, for example, the protruding part in the sub-trimming disc 20 and the wafer holding ring protruding part are fixedly connected by a bolt.
[0045] Further, in order to ensure the stable connection of the sub-polishing disc 20 and the wafer retaining ring body 10, and improve the convenience of the connection, the following can be referred to Figure 6 , Figure 6 The structure diagram of another wafer retaining ring is provided in the embodiment of the utility model. The protruding part in the sub-polishing disc 20 can be provided with a bolt 21.
[0046] The wafer retaining ring body 10 is provided with a bolt mounting hole 11 corresponding to the bolt 21.
[0047] The sub-polishing disc 20 is connected with the wafer retaining ring body 10 through the bolt 21.
[0048] It should be noted that in the embodiment, the protruding part in the sub-polishing disc 20 is provided with the bolt 21, and the bolt mounting hole 11 is correspondingly provided in the wafer retaining ring body 10. When the sub-polishing disc 20 is disassembled, only the bolt 21 needs to be tightened or loosened, thereby realizing the connection of the sub-polishing disc 20 and the wafer retaining ring body 10. In this way, the stability of the connection is ensured, and the connection efficiency is improved.
[0049] Further, in order to improve the stability of the connection of each sub-polishing disc 20 and the wafer retaining ring body 10, the bolt 21 and the sub-polishing disc 20 can be provided as an integral molding structure.
[0050] In the embodiment, the bolt 21 and the sub-polishing disc 20 are provided as an integral molding structure, which can further improve the stability of the connection of the sub-polishing disc 20 and the bolt 21, and thereby improve the stability of the connection of the sub-polishing disc 20 and the wafer retaining ring body 10.
[0051] Further, in order to avoid the loosening of the sub-polishing disc 20 caused by the rotation of the polishing disc during grinding, which affects the stability of the grinding process, each sub-polishing disc 20 can be detachably connected with the wafer retaining ring body 10 through the bolt 21 and the clamping connection.
[0052] It should be noted that in the embodiment, each sub-polishing disc 20 is detachably connected with the wafer retaining ring body 10 through the bolt 21 and the clamping connection. The bolt 21 connection ensures the stability of the connection of the sub-polishing disc 20 and the wafer retaining ring body 10, and thereby the clamping connection avoids the loosening of the sub-polishing disc 20 caused by the rotation of the polishing disc during grinding, and improves the stable connection of the sub-polishing disc 20 and the wafer retaining ring body 10 during grinding.
[0053] Further, in order to ensure that the grinding liquid smoothly acts on the inner wafer 1 through the recessed groove, the extension direction of the recessed groove can form an included angle with the radius of the wafer retaining ring body 10.
[0054] In the embodiment, the recessed grooves are arranged to have an angle with the radius of the wafer holding ring body 10, so that the resistance of fluid flow during polishing is reduced and the polishing efficiency is improved.
[0055] Further, to ensure the polishing pad 6 is polished by the sub-polishing disc 20, the sub-polishing disc 20 is arranged to be a diamond sub-polishing disc 20 at least on the side away from the wafer holding ring body 10.
[0056] It should be noted that, in the embodiment, the sub-polishing disc 20 is arranged to be a diamond sub-polishing disc 20 on the side away from the wafer holding ring body 10, so that the polishing pad 6 is polished by the diamond sub-polishing disc 20 and the polishing efficiency is improved.
[0057] The wafer holding ring provided by the embodiment of the utility model includes a wafer holding ring body 10, and a polishing disc arranged on the surface of the wafer holding ring body 10 on the polishing side, the polishing disc includes a plurality of sub-polishing discs 20 arranged independently along the circumference of the surface of the wafer holding ring body 10, and there is a gap between adjacent sub-polishing discs 20, so that a recessed groove is formed at least between adjacent sub-polishing discs 20, and each sub-polishing disc 20 is detachably connected with the wafer holding ring body 10. The polishing disc is arranged in the wafer holding ring, so that the polishing disc is in contact with the polishing pad 6, the wafer holding ring is not damaged during polishing, and the device loss rate is reduced. In addition, the polishing disc is arranged to be composed of a plurality of independently arranged sub-polishing discs 20, and each sub-polishing disc 20 is detachably connected with the wafer holding ring body 10, so that only the corresponding sub-polishing disc 20 is replaced during maintenance, the structure disassembly flexibility is improved, and the structure maintenance efficiency is further improved.
[0058] Further, the utility model discloses an embodiment through setting every sub finishing disc 20 includes the protruding part, and utilize the protruding part with wafer holding ring main part 10 connection, can guarantee the stability of sub finishing disc 20 with wafer holding ring main part 10 connection, the protruding part of sub finishing disc 20 is set as bolt 21, and the bolt mounting hole 11 is set correspondingly in wafer holding ring main part 10, when disassembling sub finishing disc 20, only need to tighten or loosen the bolt 21, and then realize the connection of single sub finishing disc 20 and wafer holding ring main part 10, improve the connection efficiency while guaranteeing the stability of connection, through the bolt 21 and sub finishing disc 20 are set as integral molding structure, can further improve the stability of sub finishing disc 20 and bolt 21 connection, and then improve the stability of sub finishing disc 20 and wafer holding ring main part 10 connection, through setting every sub finishing disc 20 is connected and the clamping connection mode with wafer holding ring main part 10 detachable connection, guarantee the stability of sub finishing disc 20 and wafer holding ring main part 10 connection through the bolt 21 connection mode, and then utilize the clamping connection mode to avoid the loosening of sub finishing disc 20 driven by polishing disc rotation when grinding, improve the stable connection of sub finishing disc 20 and wafer holding ring main part 10 when grinding, through setting the extension direction of recessed groove, and the included angle is formed between the radius of wafer holding ring main part 10, can reduce the resistance of fluid flow when grinding, improve grinding efficiency, through setting diamond sub finishing disc 20 part at least the side of sub finishing disc 20 away from wafer holding ring main part 10, can improve finishing efficiency.
[0059] Embodiment 2:
[0060] Please refer to Figure 1 , Figure 1 The utility model discloses an embodiment provides a structure diagram of wafer holding ring. Compared with the above-mentioned embodiment 1, the difference of the wafer holding ring is:
[0061] Every sub finishing disc 20 is detachably connected with wafer holding ring main part 10 through the clamping component.
[0062] It needs to be explained that, in the embodiment, every sub finishing disc 20 is detachably connected with wafer holding ring main part 10 through the clamping component, which can further improve the convenience of connection and ensure the stability of sub finishing disc 20 during grinding.
[0063] Further, in order to improve the stability of the corresponding sub finishing disc 20 and wafer holding ring main part 10 connection, the surface of the wafer holding ring main part 10 and the sub finishing disc 20 connection can be provided with a plurality of protruding structures;
[0064] The recessed grooves formed between the adjacent convex structures correspond to the recessed grooves formed between the adjacent sub-polishing discs 20.
[0065] It should be noted that the surface of the wafer retaining ring body 10 connected with the sub-polishing disc 20 is provided with a plurality of convex structures, which facilitates the connection of the sub-polishing disc 20 and the wafer retaining ring body 10. The recessed grooves are formed between the adjacent convex structures in the wafer retaining ring body 10, and the recessed grooves formed in the wafer retaining ring body 10 correspond to the recessed grooves formed between the adjacent sub-polishing discs 20, so as to ensure the communication between the recessed grooves in the wafer retaining ring body 10 and the recessed grooves in the sub-polishing disc 20, and improve the flow rate of the grinding liquid acting on the inner wafer 1 through the recessed grooves.
[0066] Further, in order to ensure the regularity of the structure, the convex structure and the sub-polishing disc 20 are arranged to coincide in the direction in which the wafer retaining ring body 10 points to the sub-polishing disc 20.
[0067] In the embodiment, the convex structure and the sub-polishing disc 20 are arranged to coincide in the direction in which the wafer retaining ring body 10 points to the sub-polishing disc 20, that is, the recessed grooves in the wafer retaining ring body 10 and the recessed grooves in the sub-polishing disc 20 coincide in the direction in which the wafer retaining ring body 10 points to the sub-polishing disc 20, so as to ensure the regularity of the structure.
[0068] The wafer retaining ring provided by the embodiment of the utility model is characterized in that each sub-polishing disc 20 is detachably connected with the wafer retaining ring body 10 through the clamping component, so that the convenience of connection is further improved, and the stability of the sub-polishing disc 20 during the grinding process is ensured. In addition, the surface of the wafer retaining ring body 10 connected with the sub-polishing disc 20 is provided with a plurality of convex structures, which facilitates the connection of the sub-polishing disc 20 and the wafer retaining ring body 10. The recessed grooves are formed between the adjacent convex structures in the wafer retaining ring body 10, and the recessed grooves formed in the wafer retaining ring body 10 correspond to the recessed grooves formed between the adjacent sub-polishing discs 20, so as to ensure the communication between the recessed grooves in the wafer retaining ring body 10 and the recessed grooves in the sub-polishing disc 20, and improve the flow rate of the grinding liquid acting on the inner wafer 1 through the recessed grooves. The convex structure and the sub-polishing disc 20 are arranged to coincide in the direction in which the wafer retaining ring body 10 points to the sub-polishing disc 20, so as to improve the regularity of the structure and facilitate the connection.
[0069] In a feasible specific embodiment, the wafer retaining ring can specifically include the following structure:
[0070] A wafer holding ring body, and a dressing disc arranged on a surface of the wafer holding ring body close to a grinding side;
[0071] The dressing disc comprises a plurality of sub-dressing discs arranged independently along the surface of the wafer holding ring body in a circumferential direction, and a gap is formed between adjacent sub-dressing discs to form a recessed groove at least between the adjacent sub-dressing discs;
[0072] Each sub-dressing disc comprises a bolt matched with the wafer holding ring body, and the wafer holding ring body is provided with a bolt mounting hole corresponding to the bolt, and the sub-dressing disc is detachably connected with the wafer holding ring body through the bolt;
[0073] The bolt and the sub-dressing disc are in an integral molding structure;
[0074] The surface of the wafer holding ring body corresponding to the connection with the sub-dressing disc is provided with a plurality of protruding structures, and a recessed groove is formed between adjacent protruding structures, and the recessed groove formed between the adjacent protruding structures is arranged corresponding to the recessed groove formed between the adjacent sub-dressing discs; the protruding structure and the sub-dressing disc coincide in a direction in which the wafer holding ring body points to the sub-dressing disc;
[0075] An included angle is formed between the extension direction of the recessed groove and the radius of the wafer holding ring body;
[0076] At least one side of the sub-dressing disc opposite to the wafer holding ring body is provided as a diamond sub-dressing disc part.
[0077] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between the various embodiments can be referred to each other.
[0078] In addition, it also needs to be explained that, in this paper, the relationship such as first and second belongs to distinguish one entity or operation from another entity or operation, and does not necessarily require or imply any actual relationship or order between the entities or operations. Moreover, the term "comprises", "includes" or other any variant is intended to cover non-exclusive inclusion.
[0079] The above has carried on the detailed introduction to the wafer holding ring provided by the utility model, the principle and implementation mode of the utility model have been described in this paper by applying specific examples, the above embodiment description is only used for helping understanding the structure of the utility model and its core idea; at the same time, for the general technical personnel in the field, according to the idea of the utility model, the specific implementation mode and application range will have the change, and the above is described, the content of the specification should not be understood as the limitation of the utility model.
Claims
1. A wafer retaining ring characterized by, The application relates to a wafer holding ring body and a trimming disc arranged on the surface of the wafer holding ring body. The trimming disc comprises a plurality of sub-trimming discs arranged independently along the surface of the wafer holding ring body, and there is a gap between adjacent sub-trimming discs to form a recessed groove between the adjacent sub-trimming discs. Each sub-trimming disc is detachably connected with the wafer holding ring body. Each sub-trimming disc comprises a protruding part matched with the wafer holding ring body.
2. The wafer holding ring of claim 1, wherein, The protruding part is a bolt.
3. The wafer holding ring of claim 2, wherein, The wafer holding ring body is provided with a bolt mounting hole corresponding to the bolt. The sub-trimming disc is connected with the wafer holding ring body through the bolt. The bolt and the sub-trimming disc are integrally formed.
4. The wafer holding ring of claim 3, wherein, Each sub-trimming disc is detachably connected with the wafer holding ring body through a clamping part.
5. The wafer holding ring of claim 1, wherein The wafer holding ring body is provided with a plurality of protruding structures corresponding to the surface connected with the sub-trimming disc.
6. The wafer holding ring of claim 1, wherein, The recessed groove is formed between adjacent protruding structures, and the recessed groove formed between the adjacent protruding structures corresponds to the recessed groove formed between the adjacent sub-trimming discs. The protruding structure and the sub-trimming disc coincide in the direction in which the wafer holding ring body points to the sub-trimming disc.
7. The wafer holding ring of claim 6, wherein, Each sub-trimming disc is detachably connected with the wafer holding ring body through bolt connection and clamping connection.
8. The wafer holding ring of claim 1, wherein, The recessed groove forms an included angle with the radius of the wafer holding ring body.
9. The wafer holding ring of claim 1, wherein, The side of the sub-trimming disc away from the wafer holding ring body is provided with a diamond sub-trimming disc part.
10. The wafer holding ring of claim 1, wherein,