Bearing disc of double-sided polishing equipment and double-sided polishing equipment

Abstract

The invention provides a bearing disc of double-face polishing equipment and the double-face polishing equipment, and the bearing disc comprises a body, a bearing plate and a supporting plate, the outer ring is fixedly assembled in the through hole of the body; the inner ring is assembled to the outer ring in the mode that the inner ring can rotate relative to the outer ring, and the inner ring is used for being in close fit with the outer circumferential face of a wafer, so that relative movement does not occur between the wafer and the inner ring in the double-face polishing process.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor wafer production, and particularly to a carrier plate for a double-sided polishing device and a double-sided polishing device. Background Art

[0002] The double-sided polishing process of wafers is one of the key steps in semiconductor manufacturing. Its purpose is to remove the damaged layer on the wafer surface, reduce the surface roughness, and achieve the planarization of the wafer. Double-sided polishing usually adopts chemical mechanical polishing technology, and the two sides of the wafer are evenly polished by carrying the wafer on a special carrier plate.

[0003] In order to achieve uniform polishing of the wafer surface, the free rotation of the wafer in the carrier plate is essential. This rotation helps the uniform distribution of the polishing liquid and the uniform contact between the polishing pad and the wafer surface, thereby reducing the non-uniformity during the polishing process and improving the flatness and polishing quality of the wafer surface. The design of the carrier plate allows the wafer to rotate during the polishing process, usually by setting through holes larger than the wafer diameter, so that the wafer can freely rotate under the action of the relative movement between the carrier plate and the polishing pad.

[0004] Although the free rotation of the wafer in the carrier plate is crucial for achieving uniform polishing, this rotation will also cause wear on the edge of the wafer. During the polishing process, the contact and friction between the wafer and the carrier plate will cause damage to the wafer edge. This damage not only affects the appearance quality of the wafer, but also may reduce the strength and reliability of the wafer. In addition, the wear on the wafer edge may also lead to accuracy problems in subsequent processing, increasing the complexity and cost of process adjustment. Therefore, how to reduce or avoid the wear on the wafer edge while ensuring the uniform polishing of the wafer has become an urgent problem to be solved in the double-sided polishing process. Summary of the Invention

[0005] The present disclosure provides a carrier plate for a double-sided polishing device and a double-sided polishing device, which can avoid wafer edge damage while ensuring the uniformity of wafer polishing.

[0006] The technical solution of the present disclosure is realized as follows: In a first aspect, the present disclosure provides a carrier plate for a double-sided polishing device, and the carrier plate includes: A body, and a through hole is formed in the body; An outer ring, and the outer ring is fixedly assembled in the through hole of the body; An inner ring, and the inner ring is assembled to the outer ring in a manner that can rotate relative to the outer ring. The inner ring is used for closely fitting with the outer peripheral surface of the wafer, so that there is no relative movement between the wafer and the inner ring during the double-sided polishing process.

[0007] In some alternative examples, the inner ring is made of a composite material composed of aramid and glass fiber.

[0008] In some alternative examples, a protrusion is formed on the inner circumferential surface of the inner ring, and the protrusion is used to cooperate with the notch of the wafer.

[0009] In some alternative examples, the carrier plate further includes a plurality of rolling elements, and the plurality of rolling elements are assembled between the outer ring and the inner ring, so that when the inner ring rotates relative to the outer ring, each rolling element rolls on the inner circumferential surface of the outer ring and the outer circumferential surface of the inner ring.

[0010] In some alternative examples, the plurality of rolling elements are spheres.

[0011] In some alternative examples, a first circumferential groove for guiding the rolling of the rolling element is formed on the inner circumferential surface of the outer ring, and a second circumferential groove for guiding the rolling of the rolling element is formed on the outer circumferential surface of the inner ring.

[0012] In some alternative examples, the carrier plate further includes a cage, and the cage is used to separate the plurality of rolling elements into a uniform distribution in the circumferential direction of the inner ring.

[0013] In a second aspect, the present disclosure provides a double-sided polishing device, and the double-sided polishing device includes the carrier plate according to the first aspect.

[0014] In some alternative examples, the main body has external teeth on the main body, and the double-sided polishing device further includes: An internal gear ring, which has external teeth on the internal gear ring; An external gear ring disposed outside the internal gear ring, which has internal teeth on the external gear ring; Wherein, the carrier plate is disposed between the internal gear ring and the external gear ring, so that the external teeth on the main body mesh with the external teeth on the internal gear ring and the internal teeth on the external gear ring.

[0015] In some alternative examples, the double-sided polishing device further includes: An upper polishing pad, which is disposed above the carrier plate to polish the upper surface of the wafer carried by the carrier plate; A lower polishing pad, which is disposed below the carrier plate to polish the lower surface of the wafer carried by the carrier plate.

[0016] The present disclosure provides a carrier plate for a double-sided polishing device and the double-sided polishing device. Since the inner ring is in close fit with the outer peripheral surface of the wafer, it effectively avoids the direct contact between the wafer and the body of the carrier plate during the polishing process, thereby reducing the wear or damage to the edge of the wafer. With the edge of the wafer protected, the overall quality of the wafer is improved, which is of great significance for improving the yield and reliability of semiconductor products. Although the inner ring is in close fit with the wafer, the inner ring can still rotate relative to the outer ring. This rotational ability ensures that the wafer can be evenly polished during the double-sided polishing process, thereby improving the uniformity and efficiency of polishing. The rotational movement helps the uniform distribution of the polishing liquid and the uniform contact between the polishing pad and the wafer surface, reduces the non-uniformity during the polishing process, and improves the flatness and polishing quality of the wafer surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. is a top view schematic diagram of a carrier plate of a double-sided polishing device provided by an embodiment of the present disclosure.

[0018] Figure 2 FIG. is a top view schematic diagram of a carrier plate of a double-sided polishing device provided by another embodiment of the present disclosure.

[0019] Figure 3 is a cross-sectional schematic diagram taken along line A-A in Figure 1 .

[0020] Figure 4 FIG. is a top view schematic diagram of a double-sided polishing device provided by an embodiment of the present disclosure.

[0021] Figure 5 FIG. is a cross-sectional schematic diagram of a double-sided polishing device provided by an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following will clearly and completely describe the technical solutions in the present disclosure with reference to the accompanying drawings in the present disclosure.

[0023] In the field of semiconductor manufacturing, the double-sided polishing process of wafers is a crucial step in ensuring the performance and reliability of chips. The core objective of this process is to remove the damaged layer on the wafer surface, reduce the surface roughness, and achieve the planarization of the wafer, which is essential for subsequent integrated circuit manufacturing. Traditional chemical mechanical polishing technology fixes the wafer on a special carrier plate and uniformly polishes the two surfaces of the wafer to achieve the above goals. To ensure uniform polishing of all parts of the wafer surface, the wafer needs to rotate freely in the carrier plate. This rotation helps the uniform distribution of the polishing liquid and the uniform contact between the polishing pad and the wafer surface, thereby reducing the non-uniformity during the polishing process and improving the flatness and polishing quality of the wafer surface. The design of the carrier plate usually includes a through hole larger than the diameter of the wafer to allow the wafer to rotate freely during the polishing process. Although this rotation is crucial for achieving uniform polishing, it also brings a significant problem: the wear of the wafer edge. During the polishing process, the contact and friction between the wafer and the carrier plate will cause damage to the wafer edge. This damage not only affects the appearance quality of the wafer but may also reduce the strength and reliability of the wafer. In addition, the wear of the wafer edge may also lead to accuracy problems in subsequent processing, increasing the complexity and cost of process adjustment.

[0024] To address this technical challenge, the present disclosure proposes a new technical solution, aiming to protect the wafer edge, reduce the wear caused by the self-rotation of the wafer, thereby improving the processing accuracy and product quality of the wafer, while reducing the complexity and cost of subsequent process adjustment. Specifically, referring to Figure 1 , the embodiment of the present disclosure provides a carrier plate 10 of a double-sided polishing device, and the carrier plate 10 may include a body 11, an outer ring 12, and an inner ring 13.

[0025] The body 11 is formed with a through hole 11H, Figure 1 and the through hole 11H is more clearly shown above the body 11. However, in fact, three through holes 11H are formed in the body 11. The outer ring 12 is fixedly assembled in the through hole 11H of the body 11, Figure 1 and the outer ring 12 in the through hole 11H at the lower left of the body 11 and the outer ring 12 in the through hole 11H at the lower right are shown. The inner ring 13 is assembled to the outer ring 12 in a manner that can rotate relative to the outer ring 12, and the inner ring 13 is used to closely cooperate with the outer peripheral surface WS of the wafer W, so that there is no relative movement between the wafer W and the inner ring 13 during the double-sided polishing process.

[0026] Since the inner ring 13 is in close fit with the outer peripheral surface WS of the wafer W, it effectively prevents the wafer W from coming into direct contact with the body 11 of the carrier plate 10 during the polishing process, thereby reducing the wear or damage to the edge of the wafer W. With the edge of the wafer W being protected, the overall quality of the wafer W is improved, which is of great significance for improving the yield and reliability of semiconductor products. Although the inner ring 13 is in close fit with the wafer W, the inner ring 13 can still rotate relative to the outer ring 12. This rotational ability ensures that the wafer W can be evenly polished during the double-sided polishing process, thereby improving the uniformity and efficiency of polishing. The rotational movement helps the uniform distribution of the polishing liquid and the uniform contact between the polishing pad and the wafer surface, reducing the non-uniformity during the polishing process and improving the flatness and polishing quality of the wafer surface.

[0027] In some embodiments of the present disclosure, the inner ring 13 can be made of a composite material composed of aramid and glass fiber.

[0028] Aramid and glass fiber are both high-performance fiber materials, and the composite material they form together has excellent wear resistance. As a component in direct contact with the wafer W, the wear resistance of the inner ring 13 is directly related to the protection effect of the wafer edge. The use of the composite material significantly improves the wear resistance of the inner ring 13 and reduces the wear of the inner ring 13 itself during the polishing process, thereby extending the service life of the carrier plate 10. The combination of aramid and glass fiber not only improves the wear resistance of the inner ring 13, but also enhances its overall strength and rigidity. This high-strength composite material makes the inner ring 13 less likely to deform when subjected to the pressure and friction generated during the polishing process, maintains a close fit with the outer peripheral surface WS of the wafer W, and ensures the stability and uniformity of the polishing process. Both aramid and glass fiber have good thermal stability, and the inner ring 13 made of the composite material can maintain its performance unchanged in the high temperature environment generated during the polishing process. This is crucial to maintaining the continuity and consistency of the polishing process, because temperature changes may affect the effectiveness of the polishing liquid and the performance of the polishing pad. During the chemical mechanical polishing process, the chemicals in the polishing liquid may corrode the inner ring 13. Aramid and glass fiber composites exhibit good chemical stability and can resist chemicals in the polishing liquid, keeping the performance and structure of the inner ring 13 from being corroded. Compared with metals or other traditional materials, aramid and glass fiber composites have a lower density, which helps to reduce the weight of the inner ring 13. The reduction in weight has a positive effect on improving the response speed of the equipment and reducing energy consumption, especially in applications that require rapid start and stop and frequent adjustment of polishing parameters. Aramid and glass fiber composites also have excellent impact resistance, which means that the inner ring 13 can withstand unexpected impacts without breaking, which is very important for protecting expensive wafers W and reducing unexpected losses in production. Aramid and glass fiber composites are lower in cost than some high-performance materials such as ceramics or special alloys, which effectively controls the production cost of the inner ring 13 and helps reduce the manufacturing cost of the entire double-sided polishing equipment.

[0029] In some embodiments of the present disclosure, see Figure 2 The inner circumferential surface 131 of the inner ring 13 may be formed with a protrusion 13P, and the protrusion 13P is used to cooperate with the notch WN of the wafer W.

[0030] The fit between the protrusions 13P on the inner peripheral surface 131 of the inner ring 13 and the notch WN of the wafer W significantly improves the fitting reliability between the inner ring 13 and the wafer W. This mechanical interlocking structure ensures that even during strong vibrations or pressure changes during the polishing process, the wafer W will not easily separate from the inner ring 13, thus maintaining the stability and uniformity of the polishing process. Due to the fit between the protrusions 13P and the notch WN, the displacement of the wafer W during the polishing process is effectively prevented, ensuring that the wafer W always remains in the correct position throughout the polishing process, which is crucial for achieving a uniform polishing effect and avoiding damage to the wafer surface. The firm fit between the inner ring 13 and the wafer W reduces the micro-movement of the wafer during the polishing process, thereby improving the polishing accuracy. This improvement in accuracy helps to produce wafers with a smoother surface and higher quality, and further improves the performance and reliability of the final semiconductor products.

[0031] In some embodiments of the present disclosure, referring to Figure 2 , the carrier plate 10 may further include a plurality of rolling elements 14, and the plurality of rolling elements 14 are assembled between the outer ring 12 and the inner ring 13, such that when the inner ring 13 rotates relative to the outer ring 12, each rolling element 14 rolls on the inner peripheral surface 121 of the outer ring 12 and the outer peripheral surface 132 of the inner ring 13.

[0032] Due to the presence of the rolling elements 14, the friction between the inner ring 13 and the outer ring 12 is rolling friction, which significantly reduces the friction coefficient, reduces energy loss, and improves the efficiency of the polishing process. Rolling friction has a lower wear rate compared to sliding friction. Therefore, the wear of the inner ring 13 and the outer ring 12 will be greatly reduced, which not only improves the durability of the carrier plate 10, but also extends its maintenance cycle and service life, and reduces the long-term operating cost. The use of the rolling elements 14 improves the rotation accuracy and stability of the inner ring 13 because rolling friction has uniformity and predictability, and the inner ring 13 can rotate more smoothly and accurately, which is crucial for achieving uniform polishing of the wafer W. The lower frictional resistance means less heat is generated during the polishing process, thereby reducing the risk of thermal deformation of the equipment and materials due to frictional heat, which is very important for maintaining the consistency of the polishing process and the processing accuracy of the wafer W.

[0033] In some embodiments of the present disclosure, referring to Figure 1 and Figure 2 , the plurality of rolling elements 14 may be spheres.

[0034] Since only the radial loads on the outer ring 12 or the inner ring 13 need to be borne, using spheres as the rolling elements 14 can simplify the structural design of the bearing plate 10. The simple geometric shape of the spheres helps reduce the complexity of design and manufacturing, thereby lowering the production cost and maintenance difficulty. Due to their perfect circular geometric properties, the spheres exhibit extremely high efficiency when bearing radial loads. This shape enables the spheres to have the largest contact area in any direction, thus providing the maximum load-bearing capacity, which is crucial for ensuring the stability of the inner ring 13 and the outer ring 12 under high loads. The uniform and predictable rolling behavior of the spheres helps improve the precision when the inner ring 13 rotates relative to the outer ring 12, which is essential for ensuring the uniformity and accuracy of the wafer W during the polishing process and contributes to improving the quality of the final product.

[0035] In some embodiments of the present disclosure, referring to Figure 3 , a first circumferential groove 121G for guiding the rolling of the rolling element 14 may be formed on the inner circumferential surface 121 of the outer ring 12, and a second circumferential groove 132G for guiding the rolling of the rolling element 14 may be formed on the outer circumferential surface 132 of the inner ring 13.

[0036] The first circumferential groove 121G and the second circumferential groove 132G provide an accurate rolling path for the rolling element 14. This accurate guidance ensures the smooth and consistent rolling of the rolling element 14 between the outer ring 12 and the inner ring 13, reduces vibration and noise during the rolling process, and improves the running smoothness of the overall polishing equipment. Through the guidance of the first circumferential groove 121G and the second circumferential groove 132G, the rolling element 14 can convert kinetic energy more effectively, thereby improving the rotation efficiency of the inner ring 13 relative to the outer ring 12. This improvement in efficiency helps reduce energy consumption, especially during the long-term running polishing process. The first circumferential groove 121G and the second circumferential groove 132G help evenly distribute the loads acting on the rolling element 14, reduce the premature wear of the rolling element 14 caused by load concentration. This even distribution helps extend the service life of the rolling element 14 and reduce the maintenance cost.

[0037] In some embodiments of the present disclosure, referring to Figure 2 , the bearing plate 10 may further include a cage 15 schematically shown by thick solid lines. The cage 15 is used to separate a plurality of rolling elements 14 into a uniform distribution in the circumferential direction of the inner ring 13.

[0038] The cage 15 evenly spaces the rolling elements 14, making the radial load distribution between the inner ring 13 and the outer ring 12 more uniform. This uniform distribution helps reduce local stress concentration and decreases the early wear of the rolling elements or grooves caused by uneven loads, thereby extending the service life of the carrier plate 10. Due to the uniform circumferential distribution of the rolling elements 14 on the inner ring 13, the balance during the rotation of the inner ring 13 relative to the outer ring 12 is improved. This balance helps reduce vibrations and oscillations during rotation, enhancing the stability and processing accuracy of the wafer W during the polishing process. The cage 15 enables the uniform distribution of the rolling elements 14, reducing the friction between the rolling elements 14, thus decreasing heat generation, which is crucial for maintaining temperature stability during the polishing process and preventing equipment performance degradation due to overheating. Since the rolling elements 14 are uniformly stressed, the wear of each rolling element 14 is more consistent, which helps optimize the service life of the rolling elements 14, avoids premature failure of the rolling elements 14 caused by local overload, and reduces the frequency of replacing the rolling elements 14 and the maintenance cost.

[0039] Referring to Figure 4 , the embodiments of the present disclosure further provide a double-sided polishing device 1, which may include a carrier plate 10 according to the foregoing embodiments of the present disclosure.

[0040] The double-sided polishing device 1 adopts the carrier plate 10, which helps achieve the uniformity of the wafer W during the polishing process and ensures that the edge of the wafer W is not damaged.

[0041] In some embodiments of the present disclosure, referring to Figure 4 and in combination with Figure 5 , the body 11 may have an outer tooth 11T of the body, and the double-sided polishing device 1 may further include: An internal gear ring 20 having an outer tooth 20T of the internal gear ring; An external gear ring 30 disposed around the internal gear ring 20, the external gear ring 30 having an internal tooth 30T of the external gear ring; wherein, the carrier plate 10 is disposed between the internal gear ring 20 and the external gear ring 30, such that the outer tooth 11T of the body meshes with the outer tooth 20T of the internal gear ring and the internal tooth 30T of the external gear ring.

[0042] Through the meshing of the outer tooth 11T of the body with the outer tooth 20T of the internal gear ring and the internal tooth 30T of the external gear ring, the double-sided polishing device 1 achieves precise transmission control. This meshing method ensures the precise positioning and motion control of the carrier plate 10 during the polishing process, improving the polishing accuracy and repeatability. The design of the internal gear ring 20 and the external gear ring 30 enhances the structural stability of the entire double-sided polishing device 1. This double-layer gear ring structure provides additional support, reducing deformations that may occur during high-load polishing, thereby improving the durability and reliability of the device.

[0043] In some embodiments of the present disclosure, referring to Figure 5 , the double-sided polishing apparatus 1 may further include: An upper polishing pad 40, which is disposed above the carrier plate 10 to polish the upper surface WU of the wafer W carried by the carrier plate 10; A lower polishing pad 50, which is disposed below the carrier plate 10 to polish the lower surface WL of the wafer W carried by the carrier plate 10.

[0044] The double-sided polishing apparatus 1 allows the simultaneous polishing of the upper surface WU and the lower surface WL of the wafer W. This design improves production efficiency because it allows the double-sided polishing to be completed in one process, reducing processing time and costs. By the combined use of the upper polishing pad 40 and the lower polishing pad 50, it can be ensured that both surfaces of the wafer W can be polished evenly. This uniformity is crucial for subsequent semiconductor manufacturing processes because it can reduce performance differences caused by surface non-uniformity.

[0045] Although not shown in the drawings, the double-sided polishing apparatus 1 according to the embodiments of the present disclosure may further include an upper platen and a lower platen, a polishing liquid supply system, a control and drive system, and additional components, etc., which will be briefly described below.

[0046] The upper platen is located above the upper polishing pad 40 and is used to fix and support the upper polishing pad 40 to ensure the stability and flatness of the upper polishing pad 40 during the polishing process. The upper platen is usually made of a hard material, such as steel or aluminum, to ensure its durability and rigidity under high pressure.

[0047] The lower platen corresponds to the upper platen. The lower platen is located below the lower polishing pad 50 and serves to support and fix the lower polishing pad 50. The design of the lower platen also needs to focus on stability and durability to maintain the consistency and reliability of the polishing process.

[0048] The polishing liquid is an indispensable component in the polishing process and contains fine abrasive particles and chemical active agents for removing the material on the surface of the wafer W through physical and chemical actions. The polishing liquid is evenly applied to the polishing pad through a dedicated supply system to ensure the uniformity and consistency of the polishing effect. The supply pump is used to pump the polishing liquid out of the storage tank and transport it to the polishing pad. The flow rate and pressure of the supply pump can be adjusted to meet different polishing requirements. The distributor is located above the polishing pad and is used to evenly distribute the polishing liquid over the entire surface of the polishing pad. The design of the distributor ensures that the polishing liquid can cover the entire polishing area to avoid local overheating and excessive wear.

[0049] The control system includes a computer and various sensors for monitoring and controlling the polishing process. The control system can adjust the pressure of the polishing pad, the flow rate of the polishing liquid, and the pressure of the supply pump to achieve the best polishing effect. The driving motor is used to drive the carrier plate 10 to rotate, and the speed and torque of the driving motor can be adjusted according to the needs of the polishing process to ensure the uniform rotation of the wafer W during the polishing process.

[0050] The cleaning system is used to clean the wafer W and the polishing pad after the polishing process. The cleaning system can remove the residual polishing liquid and abrasive particles to ensure the cleanliness of the equipment and the accuracy of the next polishing. The waste liquid collection system is used to collect and process the waste liquid generated during the polishing process. The waste liquid collection system helps to keep the working environment clean and meet the environmental protection requirements.

[0051] It should be noted that: among the technical solutions described in this disclosure, they can be arbitrarily combined without conflict.

[0052] As described above, it is only the specific implementation manner of this disclosure, but the protection scope of this disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by this disclosure can easily think of changes or substitutions, which should all be covered within the protection scope of this disclosure. Therefore, the protection scope of this disclosure should be subject to the protection scope of the claimed rights.

Claims

1. A carrier plate for a double-sided polishing device, characterized in that: The carrier plate comprises: A body, wherein the body is formed with a through hole; an outer ring, the outer ring being fixedly assembled in the through hole of the body; The inner ring is assembled to the outer ring in a manner that it can rotate relative to the outer ring, and the inner ring is used to closely cooperate with the outer peripheral surface of the wafer so that no relative movement occurs between the wafer and the inner ring during the double-sided polishing process.

2. The carrier plate of the double-sided polishing device according to claim 1, characterized in that: The inner ring is made of a composite material composed of aramid and glass fiber.

3. The carrier plate of the double-sided polishing device according to claim 1 or 2, characterized in that: A protrusion is formed on the inner circumferential surface of the inner ring, and the protrusion is used to cooperate with the notch of the wafer.

4. The carrier plate of the double-sided polishing device according to claim 1 or 2, characterized in that: The carrier plate further includes a plurality of rolling bodies, which are assembled between the outer ring and the inner ring so that when the inner ring rotates relative to the outer ring, each rolling body rolls on the inner circumferential surface of the outer ring and the outer circumferential surface of the inner ring.

5. The carrier plate of the double-sided polishing device according to claim 4, characterized in that: The plurality of rolling bodies are spheres.

6. The carrier plate of the double-sided polishing device according to claim 5, characterized in that: A first circumferential groove for guiding the rolling element to roll is formed on the inner circumferential surface of the outer ring, and a second circumferential groove for guiding the rolling element to roll is formed on the outer circumferential surface of the inner ring.

7. The carrier plate of the double-sided polishing device according to claim 4, characterized in that: The carrier plate further comprises a retaining frame, and the retaining frame is used to separate the plurality of rolling elements into uniform distribution in the circumferential direction of the inner ring.

8. A double-sided polishing device, characterized in that: The double-sided polishing apparatus comprises a carrier plate according to any one of claims 1 to 7.

9. The double-sided polishing device according to claim 8, characterized in that: The body has body external teeth, and the double-sided polishing device also includes: An inner gear ring, wherein the inner gear ring has inner gear ring external teeth; An outer gear ring disposed on the periphery of the inner gear ring, the outer gear ring having inner teeth of the outer gear ring; Wherein, the carrier plate is arranged between the inner gear ring and the outer gear ring, so that the outer teeth of the main body are meshed with the outer teeth of the inner gear ring and the inner teeth of the outer gear ring.

10. The double-sided polishing device according to claim 8 or 9, characterized in that: The double-sided polishing equipment also includes: An upper polishing pad, the upper polishing pad being arranged above the carrier plate to polish the upper surface of the wafer carried by the carrier plate; A lower polishing pad is arranged below the carrier plate to polish the lower surface of the wafer carried by the carrier plate.

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