Focusing ring, plasma etching equipment and using method of focusing ring

Abstract

The invention discloses a focusing ring, plasma etching equipment and a focusing ring using method, and belongs to the technical field of semiconductor manufacturing. The focusing ring comprises an upper ring and two or more lower rings; the upper ring and the lower ring are separately arranged, and the lower ring is arranged below the upper ring and can support the upper ring; the heights of the plurality of lower rings are different, so that the height of the upper ring can be adjusted after the lower rings are replaced. According to the focusing ring, after the original lower ring is replaced by the lower ring with higher height, the height of the upper ring can be increased, so that the influence caused by thinning of the upper surface of the upper ring can be counteracted, and the upper surface of the upper ring can be basically flush with the original upper surface before etching; therefore, the focusing ring can ensure the etching uniformity of the wafer edge in the etching process, and the service life of the focusing ring is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and particularly relates to a focus ring, a plasma etching device and a method for using the focus ring. Background Art

[0002] During the semiconductor processing, generally several steps are required to perform etching operations on semiconductor devices using a plasma etching device to remove some materials on the surface of the semiconductor devices. An electrostatic chuck is provided inside the plasma etching device, which fixes the semiconductor wafer in the chamber of the etching device. A focus ring is provided on the electrostatic chuck, which is located around the wafer to improve the etching uniformity at the wafer edge. During the plasma etching process, the electrical discontinuity at the wafer edge will cause the distortion of the plasma sheath layer at the wafer edge, resulting in the deviation of the movement trajectory of the plasma at the wafer edge. The focus ring can adjust the sheath layer profile at the wafer edge and maintain the uniformity of the plasma.

[0003] During the working process, the plasma generated by the device moves from top to bottom. When contacting the wafer, it will also contact the focus ring. The plasma has strong corrosiveness and will etch the focus ring, resulting in the removal of the top material of the focus ring. The top surface of the focus ring will gradually decrease. When the top surface of the focus ring decreases excessively, it will lose the function of improving the etching uniformity at the wafer edge, and the focus ring may be scrapped.

[0004] The countermeasure in the prior art is to lift the height of the focus ring through a mechanical mechanism to compensate for the influence caused by the etching of the top surface of the focus ring. Chinese invention patent CN118280803A discloses a focus ring adjusting device, including a retaining ring and an expansion member. The retaining ring is used to support the focus ring, and the expansion member is installed in the first installation groove of the retaining ring. When the expansion member expands, it is used to directly or indirectly lift the focus ring. Although it can lift the height of the focus ring, the precise control of the lifting height of the focus ring depends on the action precision of the expansion member. However, the expansion amplitude of the expansion member is difficult to precisely control, and the expansion action of the expansion member requires additional mechanical structures for control. Its overall structure is complex and the cost is high. Summary of the Invention

[0005] The present invention provides a focus ring, a plasma etching device and a method for using the focus ring, in order to at least partially solve the above technical problems.

[0006] As a first aspect of the present invention, there is provided a focusing ring for a plasma etching apparatus, the focusing ring comprising an upper ring and two or more lower rings; the upper ring and the lower rings are separately arranged, and the lower rings are disposed below the upper ring and can support the upper ring; the heights of the plurality of lower rings are different so as to be able to adjust the height of the upper ring after replacing the lower rings.

[0007] Wherein, the heights of the plurality of lower rings form an arithmetic progression.

[0008] Wherein, the common difference of the arithmetic progression is 0.1 mm, 0.15 mm or 0.2 mm.

[0009] Wherein, the bottom of the upper ring is provided with an annular edge guard, and the lower rings are disposed within the edge guard.

[0010] Wherein, the lower rings and the upper ring are made of different materials.

[0011] Wherein, the lower rings are silicon carbide rings; or both the upper ring and the lower rings are made of silicon carbide.

[0012] Wherein, the focusing ring further comprises a hook, and a plurality of grooves are provided on the outer peripheral wall of the lower ring, and the hook can be inserted into the grooves to be able to lift the lower ring upward.

[0013] Wherein, corresponding ring grooves with a V-shaped cross section are provided below the upper ring and above the lower rings, and a plurality of balls for supporting the upper ring are provided in the ring grooves.

[0014] As a second aspect of the present invention, there is also provided a plasma etching apparatus, comprising an electrostatic chuck, and further comprising the above-mentioned focusing ring, and the focusing ring is sleeved on the electrostatic chuck.

[0015] As a third aspect of the present invention, there is also provided a method for using a focusing ring for the above-mentioned focusing ring, comprising the following steps: Prepare a plurality of upper rings of brand-new focusing rings and number them from 1 to n; Prepare a set of lower rings and number them from 1 to m in ascending order of height; Pair the No. 1 upper ring with the No. 1 lower ring for use; During maintenance, pair the in-use upper ring with the next-numbered lower ring for use, and pair a new upper ring with the No. 1 lower ring for use; When the upper ring is paired with the No. m lower ring for use, scrap the upper ring.

[0016] Based on the above solution, the focus ring, plasma etching equipment and method for using the focus ring of the present invention have at least one of the following beneficial effects compared with the prior art: After the lower ring of the focus ring of the present invention is replaced with a lower ring having a higher height, the height of the upper ring can be increased, so that the influence caused by the thinning of the upper surface of the upper ring can be offset, and the upper surface of the upper ring can be kept substantially flat with the original upper surface before etching, so that the focus ring can ensure the etching uniformity of the wafer edge during the etching process and increase the service life of the focus ring. The focus ring of the present application does not require a motion mechanism to increase the height of the focus ring, and thus has the characteristics of simple structure, reliable use and low cost. Compared with the prior art solution of changing the height of the upper ring through a motion mechanism, the existing structure of the plasma etching equipment does not need to be changed, and the existing focus ring can be directly replaced, which is more conducive to popularization. The lower ring of the present application can be replaced during the routine maintenance of the plasma equipment, and the operation and maintenance process is almost the same as the original process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below.

[0018] Figure 1 It is a schematic cross-sectional structure diagram of the focus ring of the present invention; Figure 2 It is Figure 1 a schematic diagram of the upper ring of the focus ring shown; Figure 3 It is Figure 1 a schematic diagram of the lower ring of the focus ring shown; Figure 4 It is a schematic cross-sectional structure diagram of another embodiment of the focus ring of the present invention; Figure 5 It is Figure 4 a schematic diagram of the upper ring in; Figure 6 It is a schematic cross-sectional structure diagram of another embodiment of the focus ring of the present invention; Figure 7 It is Figure 6 a schematic diagram of the upper ring in; Figure 8 It is Figure 6 a schematic diagram of the lower ring in; Figure 9 It is a schematic diagram of the combination of the focus ring and the electrostatic chuck in the plasma etching equipment of the present invention.

[0019] In the above drawings, the meanings of the reference numerals are as follows: In the figure: 100, upper ring; 110, edge guard; 120, upper ring groove; 200, lower ring; 210, groove body; 220, lower ring groove; 300, ball. Detailed implementation mode

[0020] To better understand the technical solutions of the embodiments of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope protected by the embodiments of the present invention.

[0022] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0023] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0024] In the present invention, unless otherwise clearly defined and limited, the terms "installation", "connection", "connection", "fixation", etc. 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, an electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] See Figures 1 to 9 , the present invention discloses a focusing ring, which is used for the plasma etching equipment used in the production process of semiconductor devices.

[0026] As Figures 1 to 3 shown, Figure 1Schematic cross-sectional structure diagram of the focusing ring of the present invention; Figure 2 is Figure 1 Schematic diagram of the upper ring of the focusing ring shown; Figure 3 is Figure 1 Schematic diagram of the lower ring of the focusing ring shown. The Figures 1 to 3 are all cross-sectional views. The focusing ring includes an upper ring 100 and two or more lower rings 200. Both the upper ring 100 and the lower ring 200 are circular ring structures, and after the upper ring 100 and the lower ring 200 are combined, they function the same as the existing focusing ring. When the focusing ring is applied in a plasma etching equipment, the wafer is disposed within the focusing ring, and the upper surface of the wafer is substantially flush with the upper surface of the focusing ring. The focusing ring can improve the etching uniformity of the wafer edge, making the etching degree of the wafer edge and the center relatively uniform, so as to improve the yield.

[0027] The upper ring 100 and the lower ring 200 are separately arranged, that is, the upper ring 100 and the lower ring 200 are independent manufactured split devices, and the two are assembled together during use. The lower ring 200 is disposed below the upper ring 100 and can support the upper ring 100. In some embodiments, the top of the lower ring 200 can be provided with a flat top surface, and the bottom of the upper ring 100 is provided with a flat bottom surface. The bottom surface of the upper ring 100 contacts the top surface of the lower ring 200, so that the lower ring 200 can support the upper ring 100. The heights of these lower rings 200 are different. In this way, after replacing the lower ring 200, the height of the upper ring 100 can be adjusted.

[0028] During the use process, since the plasma generated by the plasma etching equipment continuously etches the upper ring 100, the upper surface of the upper ring 100 gradually loses material and becomes thinner. After replacing the original lower ring with a lower ring 200 with a higher height, the height of the upper ring 100 can be increased, which can offset the influence caused by the thinning of the upper surface of the upper ring 100, so that the upper surface of the upper ring 100 can be kept substantially flush with the original upper surface before etching, thereby enabling the focusing ring to ensure the etching uniformity of the wafer edge during the etching process and increasing the service life of the focusing ring. The focusing ring of the present application does not require a motion mechanism to lift the height of the focusing ring, so it has the characteristics of simple structure, reliable use and low cost. Compared with the prior art solution of changing the height of the upper ring 100 through a motion mechanism, it does not need to change the existing structure of the plasma etching equipment, and can directly replace the existing focusing ring, which is more conducive to promotion. The lower ring 200 of the present application can be replaced during the routine maintenance of the plasma equipment, and the operation and maintenance process is almost the same as the original process.

[0029] Since the lower ring 200 has a certain height and the lower ring 200 can be precision machined using processing equipment, the height of the lower ring 200 can reach very precise dimensions. In this way, existing processing equipment can be used to precisely adjust the height of the upper ring 100 with relatively low difficulty and implementation cost.

[0030] The upper ring 100 and the lower ring 200 of the focusing ring can be made of the same material or different materials. In some embodiments, the upper ring 100 can be made of materials such as silicon carbide, silicon nitride, and boron carbide. The lower ring 200 can be made of materials such as silicon carbide, silicon nitride, and boron carbide. Preferably, both the upper ring 100 and the lower ring 200 are made of silicon carbide.

[0031] The heights of these lower rings 200 can be set to form an arithmetic progression. By arranging the lower rings 200 in ascending order and replacing one lower ring 200 each time, the upper ring 100 of the focusing ring can be raised by the same height. In some embodiments, the common difference of the arithmetic progression of these lower rings 200 can be set to 0.1 mm, 0.15 mm, or 0.2 mm.

[0032] In one embodiment, the number of the lower rings 200 is 6, and the heights from low to high are 15 mm, 15.1 mm, 15.2 mm, 15.3 mm, 15.4 mm, 15.5 mm, numbered from 1 to 6. The upper ring 100 is first paired with the lower ring with a height of 15 mm and numbered 1. Then, during routine maintenance, the upper ring 100 is paired with the lower ring with a height of 15.1 mm and numbered 2. In this way, by changing the height of the upper ring 100, the upper ring 100 can be continuously used and play a role in improving the etching uniformity of the wafer edge, thereby extending the service life of the upper ring 100.

[0033] See Figure 3 , in some embodiments, a plurality of grooves 210 are provided on the outer peripheral wall of the lower ring 200. The focusing ring includes hooks that can be inserted into the grooves 210 to be able to lift the lower ring 200 upward. When the lower ring 200 is installed on the plasma etching equipment, the lower ring 200 is sleeved on the electrostatic chuck. After the upper ring 100 is removed, since the height of the lower ring 200 is relatively low, the lower ring 200 can be conveniently separated from the electrostatic chuck through the hooks. The operator holds a hook in each hand, and each hook is respectively inserted into the groove 210 on one side of the lower ring 200. When the operator raises both hands, the lower ring 200 can be lifted, and when the operator lowers both hands, the lower ring 200 can be lowered.

[0034] These grooves 210 can be arranged at the middle position of the outer peripheral wall of the lower ring 200, or can be arranged at the bottom position of the outer peripheral wall. The grooves 210 can be in the shape of rectangular grooves or the like, or can be arranged as round holes. These grooves 210 are evenly distributed around the axis of the lower ring 200. The number can be two or more.

[0035] See Figure 4 and Figure 5 , Figure 4 is a schematic cross-sectional structure view of another embodiment of the focusing ring of the present invention. Figure 5 is Figure 4 a schematic view of the upper ring in . In this embodiment, an annular edge protection 110 is provided at the bottom of the upper ring 100, and the lower ring 200 is arranged within the edge protection 110. The edge protection 110 at least partially surrounds the lower ring 200, which can reduce the outer surface area of the lower ring 200 exposed to the plasma environment, reduce the damage caused by the plasma, extend the service life of the lower ring 200, and make the service life of the lower ring 200 much longer than that of the upper ring 100.

[0036] As Figures 6 to 8 shown, Figure 6 is a schematic cross-sectional structure view of another embodiment of the focusing ring of the present invention. Figure 7 is Figure 6 a schematic view of the upper ring in , Figure 8 is Figure 6 a schematic view of the lower ring in . In one embodiment, oppositely positioned ring grooves with a V-shaped cross-section are provided below the upper ring 100 and above the lower ring 200, and a plurality of balls 300 for supporting the upper ring 100 are arranged in the ring grooves. Specifically, an upper ring groove 120 is provided below the upper ring 100, and a lower ring groove 220 is provided above the lower ring 200. The upper ring groove 120 and the lower ring groove 220 are oppositely positioned. When the upper ring 100 is placed above the lower ring 200, the upper ring groove 120 can be buckled on the lower ring groove 220.

[0037] The balls 300 are placed in the lower annular groove 220, and these balls 300 are in contact with the V-shaped wall surface of the lower annular groove 220. The balls 300 are spherical structures, and the sizes of the balls 300 placed in the lower annular groove 220 are equal. By strictly controlling and screening balls 300 with the same diameter size, the balls 300 can provide a good supporting effect and keep the upper surface of the upper ring 100 horizontal. The upper part of the balls 300 is in contact with the V-shaped wall surface of the upper annular groove 120, so that the upper ring 100 can be supported. That is to say, the balls 300 separate the upper ring 100 from the lower ring 200, and the upper ring 100 can rotate with the support of the balls 300. By providing a protective edge 110 on the upper ring 100, the balls 300 can also be surrounded and protected by the protective edge to prevent them from being directly bombarded by the plasma.

[0038] During the working process, when the upper ring 100 and the lower ring 200 are under different heating conditions, their expansion rates are different. The upper ring 100 can have a certain relative sliding with the balls 300 but does not come out, avoiding the problem that the upper ring 100 and the lower ring 200 may be stuck due to the heating problem.

[0039] The material of the balls 300 can be selected as silicon carbide and can be set to various different diameters. By replacing the balls 300 with different diameters, the height of the upper ring 100 can also be changed. The larger the diameter of the balls 300, the higher the height of the upper ring 100 can be made. However, the upper annular groove 120 and the lower annular groove 220 do not need to be adjusted to adapt to the balls 300. Therefore, by setting balls 300 with various different diameters, the height of the upper ring 100 can also be changed. The balls 300 and the lower ring 200 can be used in combination, so that the height of the upper ring 100 has a larger adjustment range and more adjustable heights to choose from. Under some conditions, without replacing the lower ring, only by replacing the balls with a larger diameter, the purpose of raising the upper ring and adjusting the height of the upper ring can also be achieved.

[0040] The present invention discloses a method for using a focusing ring, which is used for the above-mentioned focusing ring and includes the following steps.

[0041] Prepare multiple brand-new upper rings of the focusing ring and number them from 1 to n; Prepare a set of lower rings and number them from 1 to m in ascending order of height; Pair the No. 1 upper ring with the No. 1 lower ring for use; During maintenance, pair the in-use upper ring with the next-numbered lower ring for use, and pair a new upper ring with the No. 1 lower ring for use; When the upper ring is paired with the No. m lower ring for use, scrap the upper ring.

[0042] In some embodiments, the following steps are further included: when the upper ring and the lower ring are provided with V-shaped ring grooves and a plurality of balls with different diameters, the height of the upper ring is adjusted by selecting balls with appropriate diameters. When a certain upper ring is paired with a certain lower ring, if the height of the upper ring is still insufficient, balls with a larger diameter are replaced. If the height of the upper ring is too high, balls with a smaller diameter are replaced. Of course, it is also possible to not pair the upper ring with a new lower ring, and only by replacing balls with different diameters, the purpose of adjusting the height of the upper ring can be achieved.

[0043] The method for using this focusing ring can, during routine maintenance, pair the upper ring in the focusing ring with a lower ring having a higher height, so as to increase the height of the upper ring, offset the adverse effects brought about by plasma etching of the upper ring 100, and thus extend the service life of the focusing ring. The following will further elaborate with specific embodiments.

[0044] In one embodiment, the number of brand-new upper rings 100 of this focusing ring prepared is 5, which are numbered from 1 to 5, and the specifications of these 5 upper rings 100 are exactly the same.

[0045] Prepare a set of lower rings 200. The number of this set of lower rings 200 is 5, and they are numbered from 1 to 5 in ascending order of height. The structures of these lower rings 200 are exactly the same, but their heights are different. The heights of these lower rings 200 form an arithmetic sequence with a common difference of 0.2 mm. These lower rings 200 can be paired with any one of the upper rings 100 for use.

[0046] During use, the 1st upper ring 100 and the 1st lower ring 200 are first paired for use. Both are installed in the plasma etching equipment. The plasma etching equipment then starts the etching operation on the wafer.

[0047] The routine maintenance time of the plasma etching equipment is 200 hours. The plasma etching equipment needs to be shut down for maintenance every 200 consecutive working hours. During each routine maintenance, first take out this focusing ring, and then pair the upper ring in use with the lower ring of the next number, and pair a new upper ring with the 1st lower ring.

[0048] During the 1st routine maintenance, the 1st upper ring is paired with the 2nd lower ring for use, and then the 2nd upper ring is paired with the 1st lower ring for use. In this way, since the 1st upper ring has been used for a period of time, the height of its upper surface has decreased under the action of the plasma. By pairing the 1st upper ring with the 2nd lower ring, the height of the 1st upper ring can be increased, thus compensating for the problem of the decrease in the height of the upper surface of the 1st upper ring. Since the 2nd lower ring has not been used but is in a brand-new state, it is paired with the 1st upper ring.

[0049] During the second routine maintenance, the upper ring No. 1 is paired with the lower ring No. 3 for use, the upper ring No. 2 is paired with the upper ring No. 2 for use, and then the brand-new upper ring No. 3 is paired with the lower ring No. 1 for use.

[0050] During the third routine maintenance, the upper ring No. 1 is paired with the lower ring No. 4 for use, the upper ring No. 2 is paired with the upper ring No. 3 for use, the upper ring No. 3 is paired with the upper ring No. 2 for use, and then the brand-new upper ring No. 4 is paired with the lower ring No. 1 for use.

[0051] During the fourth routine maintenance, the upper ring No. 1 is paired with the lower ring No. 5 for use, the upper ring No. 2 is paired with the upper ring No. 3 for use, the upper ring No. 3 is paired with the upper ring No. 2 for use, the upper ring No. 4 is paired with the upper ring No. 3 for use, and then the brand-new upper ring No. 5 is paired with the lower ring No. 1 for use.

[0052] During the fifth routine maintenance, the upper ring No. 2 is paired with the upper ring No. 4 for use, the upper ring No. 3 is paired with the upper ring No. 3 for use, the upper ring No. 4 is paired with the upper ring No. 2 for use, and then the brand-new upper ring No. 5 is paired with the lower ring No. 1 for use. After the upper ring No. 1 has been paired with all the lower rings and reached the end of its service life, the upper ring No. 1 is scrapped, and a new upper ring is taken out and numbered continuously.

[0053] From the operation methods of the above exemplary embodiments, it can be seen that the focusing ring of the present application can be used multiple times, and the height of the upper ring is increased during each maintenance, thereby extending the service life of the focusing ring. Moreover, after the service life of the upper ring expires, only the upper ring needs to be scrapped, while the lower ring can be used repeatedly indefinitely, greatly reducing the use cost.

[0054] The present invention also discloses a plasma etching device, which is used for plasma etching processing of wafers in the field of semiconductor manufacturing. The plasma etching device includes an electrostatic chuck and also includes the above-mentioned focusing ring, and the focusing ring is sleeved on the electrostatic chuck.

[0055] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0056] The above are only the preferred embodiments of the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the embodiments of the present invention shall be included within the scope of protection of the embodiments of the present invention.

Claims

1. A focusing ring for a plasma etching apparatus, characterized in that, The focusing ring includes an upper ring and two or more lower rings; the upper ring and the lower rings are separately arranged, and the lower rings are arranged below the upper ring and can support the upper ring; the heights of the multiple lower rings are different so that the height of the upper ring can be adjusted after replacing the lower rings.

2. The focusing ring according to claim 1, characterized in that, The heights of the multiple lower rings form an arithmetic progression.

3. The focusing ring according to claim 2, wherein The common difference of the arithmetic progression is 0.1 mm, 0.15 mm or 0.2 mm.

4. The focusing ring according to claim 1, wherein A circular edge guard is provided at the bottom of the upper ring, and the lower rings are arranged within the edge guard.

5. The focusing ring according to claim 1, characterized in that, The materials of the lower rings and the upper ring are different.

6. The focusing ring according to claim 1, wherein The lower rings are silicon carbide rings; or the materials of both the upper ring and the lower rings are silicon carbide.

7. The focusing ring according to claim 1, characterized in that, The focusing ring further includes a hook. A plurality of grooves are provided on the outer peripheral wall of the lower ring, and the hook can be inserted into the grooves to lift the lower ring upward.

8. The focusing ring according to claim 1, characterized in that, Ring grooves with a V-shaped cross section and corresponding positions are provided below the upper ring and above the lower rings, and a plurality of balls for supporting the upper ring are provided in the ring grooves.

9. The focusing ring according to claim 8, wherein The balls have a variety of different diameter sizes.

10. A plasma etching apparatus, including an electrostatic chuck, characterized in that, It further includes the focusing ring according to any one of claims 1 to 9, and the focusing ring is sleeved on the electrostatic chuck.

11. A method for using a focusing ring, which is used for the focusing ring according to any one of claims 1 to 9, characterized in that, It includes the following steps: Prepare multiple brand-new upper rings of the focusing ring and number them from 1 to n; Prepare a set of lower rings and number them from 1 to m in ascending order of height; Pair the No. 1 upper ring with the No. 1 lower ring for use; During maintenance, pair the in-use upper ring with the next-numbered lower ring for use, and pair a new upper ring with the No. 1 lower ring for use; When the upper ring is paired with the No. m lower ring for use, scrap the upper ring.

12. The method for using a focusing ring according to claim 11, wherein It further includes the following steps: when the upper ring and the lower ring are provided with V-shaped ring grooves and are provided with a variety of different diameter balls, adjust the height of the upper ring by selecting balls with a suitable diameter.

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