Magnetic transmission device for semiconductor cleaning

Abstract

The invention discloses a magnetic transmission device for semiconductor cleaning, and relates to the technical field of semiconductor cleaning, the magnetic transmission device comprises a magnetic transmission mechanism, an auxiliary mechanism is arranged on the magnetic transmission mechanism, the magnetic transmission mechanism comprises a magnetic suspension motor, and a main shaft is arranged in the magnetic suspension motor; a magnet driver is arranged on the surface of each L-shaped frame, a wafer chuck is additionally arranged at the top of the first mounting ring, and a main magnet is magnetically attracted to the top of each magnet driver. According to the invention, through the arrangement of a new magnetic transmission mechanism, particle pollutants can be prevented from being generated to cause wafer pollution; meanwhile, liquid medicine can be prevented from permeating into a transmission mechanism, hardware corrosion is avoided, and cavity pollution is avoided.

Description

Technical Field

[0001] This invention relates to the field of semiconductor cleaning technology, specifically to a magnetic drive device for semiconductor cleaning. Background Technology

[0002] Semiconductors are materials whose conductivity at room temperature is between that of conductors and insulators. The conductivity of such semiconductor materials can be changed by doping. A semiconductor wafer is a silicon wafer made with semiconductors as the core material.

[0003] In the magnetic drive device of semiconductor wafer cleaning machine, contact sealing, contact application of relative moving parts and contact transmission sealing are common modes. Components in these modes are prone to generating micro-particle contaminants during operation. At the same time, the chemical solutions used for cleaning are also prone to seeping into the transmission mechanism, causing hardware corrosion problems. That is, the corrosion products and particles generated will further contaminate the cleaning chamber and affect the cleanliness of the wafer.

[0004] Therefore, we propose a new magnetic drive device for semiconductor cleaning to solve the problems mentioned in the background art. Summary of the Invention

[0005] The purpose of this invention is to provide a magnetic drive device for semiconductor cleaning. By setting a new magnetic drive mechanism, particulate contaminants can be avoided from being generated and causing wafer contamination. At the same time, it can also prevent the chemical solution from seeping into the drive mechanism, causing hardware corrosion and contaminating the cavity, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a magnetic drive device for semiconductor cleaning, comprising a magnetic drive mechanism, an auxiliary mechanism provided on the magnetic drive mechanism, the magnetic drive mechanism including a magnetic levitation motor, a main shaft provided inside the magnetic levitation motor, two symmetrical L-shaped frames fixed to the top of the magnetic levitation motor, each L-shaped frame having a magnet driver on its surface, a bottom stabilizing seat fixed to the top of the magnetic levitation motor, a top stabilizing seat fixedly connected to the top of the main shaft, a top cover fixedly connected to the top of the top stabilizing seat, a circular tube mounted on the top of the circular tube, a first mounting ring placed on the top of the circular tube, a wafer chuck mounted on the top of the first mounting ring, a support plate fixedly sleeved on the outer wall of the circular tube near the top, a main magnet magnetically attracted to the top of each magnet driver, a second mounting ring movably sleeved on the outer wall of the first mounting ring, two symmetrical slots pre-set at the bottom of the second mounting ring, two slots pre-set at the bottom of the support plate, and a wafer body movably engaged on the wafer chuck.

[0007] Preferably, the magnetic levitation motor is used to drive the main shaft to rotate, the magnet driver is used to control the movement of the main magnet, the main shaft is rotatably connected to the inside of the circular tube through the bearing, the top end of the top cover is movably sleeved inside the middle through hole of the top of the wafer chuck, and the bottom of the second mounting ring is fixed to the top of the support plate.

[0008] Preferably, the interior of each slot is connected to the interior of each hole, the top of each main magnet is located inside each hole, the second mounting ring is located inside the top groove of the wafer chuck, and the first mounting ring is fixedly sleeved on the top outer surface of the top cover.

[0009] Preferably, the auxiliary mechanism includes a grooved ring, and each of the two L-shaped frames has a first rectangular groove on its opposite side and a rectangular hole on its opposite side. The interior of each rectangular hole is connected to the interior of each first rectangular groove.

[0010] Preferably, the grooved ring is rotatably connected between the interiors of the two first rectangular grooves, and each of the two magnet drivers has an L-shaped locking block fixed on its opposite side. Each L-shaped locking block is movably fitted between the interior of the corresponding rectangular hole and the interior of the corresponding first rectangular groove.

[0011] Preferably, two perforated plates are fixed to the surface of one of the L-shaped frames, and a first perforated block, a second perforated block, and a third perforated block are fixed to the outer wall of the grooved ring. A perforated clamping rod is provided between the interior of the two perforated plates and the interior of the third perforated block.

[0012] Preferably, a buckle is installed at the round hole of the perforated rod, the top of the grooved ring is pre-set with a second rectangular groove and a third rectangular groove, the snap-fit ​​end of the L-shaped block is located inside the grooved ring, and the snap-fit ​​end of the L-shaped block is adapted to the second rectangular groove and the third rectangular groove.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] 1. In this invention, by setting a new magnetic transmission mechanism, particulate contaminants can be avoided from being generated and causing wafer contamination. At the same time, it can also prevent liquid chemicals from seeping into the transmission mechanism, causing hardware corrosion and contaminating the cavity. Through the cooperation of the magnet driver, main magnet, card slot, card hole, spring inside the wafer chuck and magnet inside the wafer chuck, the synchronous transmission disk inside the wafer chuck can be fixed. Through the cooperation of the magnetic levitation motor, main shaft, top stabilizer, top cover, first mounting ring, bottom stabilizer, connector inside the wafer chuck, outer shell of the wafer chuck and round tube, all the rotating clamping pins on the wafer chuck can be rotated simultaneously to lock the wafer body placed on the wafer chuck. When releasing, all the rotating clamping pins can be reversed.

[0015] 2. In this invention, by setting an auxiliary mechanism, the magnet driver can be quickly assembled and disassembled on the L-shaped frame. Through the cooperation of two perforated plates, a third rectangular block, a locking rod, a grooved ring, an L-shaped locking block and a buckle, the magnet driver can be tightly fixed on the corresponding L-shaped frame. Through the cooperation of rectangular holes, a first rectangular groove, a second rectangular groove and a third rectangular groove, the corresponding L-shaped locking block can be removed from the corresponding L-shaped frame. Attached Figure Description

[0016] Figure 1 This is a partial cross-sectional view of the wafer chuck release mechanism in the magnetic drive mechanism of a magnetic drive device for semiconductor cleaning according to the present invention.

[0017] Figure 2 This is a top-view perspective view of a magnetic drive device for semiconductor cleaning according to the present invention.

[0018] Figure 3 This is a partial cross-sectional view of the wafer chuck stopping rotation in the magnetic drive mechanism of a magnetic drive device for semiconductor cleaning according to the present invention.

[0019] Figure 4 This is a partial perspective view from a low angle of view of a magnetic drive device for semiconductor cleaning according to the present invention;

[0020] Figure 5 This is a partial cross-sectional perspective view from the side of a magnetic drive device for semiconductor cleaning according to the present invention.

[0021] Figure 6 This is a cross-sectional view of the wafer chuck and wafer body of a magnetic drive device for semiconductor cleaning according to the present invention.

[0022] Figure 7 This is a top view of the structure of a wafer body in a released state within a wafer chuck, according to a magnetic drive device for semiconductor cleaning according to the present invention.

[0023] Figure 8 This is a top-view schematic diagram of the wafer body structure in a clamped state within a wafer chuck, as per the magnetic drive device for semiconductor cleaning according to the present invention.

[0024] In the diagram: 1. Magnetic transmission mechanism; 101. Magnetic levitation motor; 102. Main shaft; 103. L-shaped frame; 104. Magnet driver; 105. Support plate; 106. Bottom stabilizer; 107. Top stabilizer; 108. Top cover; 109. Wafer chuck; 110. Circular tube; 111. Main magnet; 112. First mounting ring; 113. Slot; 114. Slot; 115. Wafer body; 116. Second mounting ring; 2. Auxiliary mechanism; 201. Grooved ring; 202. Rectangular hole; 203. First rectangular slot; 204. Perforated plate; 205. First perforated block; 206. Second perforated block; 207. Third perforated block; 208. Perforated locking rod; 209. Buckle; 210. Second rectangular slot; 211. L-shaped locking block; 212. Third rectangular slot. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1: Please refer to Figures 1-8As shown, the present invention provides a technical solution: a magnetic drive device for semiconductor cleaning, including a magnetic drive mechanism 1, the magnetic drive mechanism 1 including a magnetic levitation motor 101, a main shaft 102 disposed inside the magnetic levitation motor 101, two symmetrical L-shaped frames 103 fixed to the top of the magnetic levitation motor 101, each L-shaped frame 103 having a magnet driver 104 disposed on its surface, a bottom stabilizing seat 106 fixed to the top of the magnetic levitation motor 101, a top stabilizing seat 107 fixedly connected to the top of the main shaft 102, a top cover 108 fixedly connected to the top of the top stabilizing seat 107, a circular tube 110 mounted on the top of the bottom stabilizing seat 106, a first mounting ring 112 placed on the top of the circular tube 110, a wafer chuck 109 mounted on the top of the first mounting ring 112, a support plate 105 fixedly sleeved on the outer wall of the circular tube 110 near the top, and a main magnet 111 magnetically attracted to the top of each magnet driver 104. A second mounting ring 116 is movably fitted onto the outer wall of ring 112. The bottom of the second mounting ring 116 has two symmetrical slots 113. The bottom of the support plate 105 has two slots 114. A wafer body 115 is movably fitted onto the wafer chuck 109. A magnetic levitation motor 101 is used to drive the spindle 102 to rotate. A magnet driver 104 is used to control the movement of the main magnet 111. The spindle 102 is rotatably connected to the inside of the circular tube 110 through a bearing. The top of the top cover 108 is movably fitted into the middle through hole at the top of the wafer chuck 109. The bottom of the second mounting ring 116 is fixed to the top of the support plate 105. The inside of each slot 113 is connected to the inside of each slot 114. The top of each main magnet 111 is located inside each slot 114. The second mounting ring 116 is located inside the top groove of the wafer chuck 109. The first mounting ring 112 is fixedly fitted onto the outer surface of the top of the top cover 108.

[0027] In this embodiment, when it is necessary to clamp the wafer body 115, the wafer body 115 is first placed on the wafer chuck 109. Then, the two magnet actuators 104 are activated simultaneously, and their magnetic field directions are changed so that the top of the magnet actuator 104 and the bottom of the corresponding main magnet 111 are in a repulsive relationship. That is, the two main magnets 111 are pushed completely into the corresponding slots 114 by the principle of magnetic force. When the two main magnets 111 are completely inside the corresponding slots 114, the tops of the two main magnets 111 are exactly at their respective positions. Inside the slot 113, the top of each main magnet 111 is in an opposite pole attraction state with the bottom of the corresponding magnet inside the wafer chuck 109. At this time, the synchronous drive disk inside the wafer chuck 109 is tightly fixed by the spring inside the wafer chuck 109 in the initial state. When the synchronous drive disk inside the wafer chuck 109 is fixed, the magnetic levitation motor 101 is started. The started magnetic levitation motor 101 drives the main shaft 102 to rotate through the bottom stabilizing base 106, the circular tube 110 and the corresponding bearing. Simultaneously, the rotating spindle 102, through the cooperation of the circular tube 110 and the top stabilizing seat 107, drives the top cover 108 to rotate. When the top cover 108 rotates, it drives the first mounting ring 112 to rotate. The rotating first mounting ring 112 then drives the outer shell of the wafer chuck 109 to rotate. The rotating outer shell of the wafer chuck 109, in cooperation with the synchronous transmission disk and the connecting parts inside the wafer chuck 109 (which are in a fixed state), drives the rotating clamping pin on the wafer chuck 109 to rotate, thus holding the wafer body 1... 15. When clamping, when it is necessary to remove the processed wafer body 115 from the wafer chuck 109, the outer shell of the wafer chuck 109 is reversed to the initial position, and the wafer body 115 is removed from the wafer chuck 109. Then, the magnetic field direction of the two magnet drivers 104 is changed, and the two main magnets 111 are magnetically attracted and reset to their original positions. That is, by using this magnetic transmission mechanism 1, particulate contaminants can be avoided from being generated, causing the wafer body 115 to be contaminated. At the same time, it can also prevent the liquid from seeping into the transmission mechanism, causing hardware corrosion and contaminating the cavity.

[0028] Example 2: According to Figures 1-5As shown, the magnetic transmission mechanism 1 includes a magnetic levitation motor 101. Two symmetrical L-shaped frames 103 are fixed to the top of the magnetic levitation motor 101. Each L-shaped frame 103 has a magnet actuator 104 on its surface. An auxiliary mechanism 2 is provided on the magnetic transmission mechanism 1. The auxiliary mechanism 2 includes a grooved ring 201. First rectangular grooves 203 are pre-set on the opposite sides of the two L-shaped frames 103, and rectangular holes 202 are pre-set on the opposite sides of the two L-shaped frames 103. The interior of each rectangular hole 202 communicates with the interior of each first rectangular groove 203. The grooved ring 201 is rotatably connected between the interiors of the two first rectangular grooves 203. L-shaped locking blocks 211 are fixed to the opposite sides of the two magnet actuators 104. Each L-shaped locking block... Block 211 is movably fitted between the corresponding rectangular hole 202 and the corresponding first rectangular groove 203. Two perforated plates 204 are fixed on the surface of one of the L-shaped frames 103. The outer wall of the grooved ring 201 is fixed with a first perforated block 205, a second perforated block 206 and a third perforated block 207. A perforated locking rod 208 is provided between the inside of the two perforated plates 204 and the inside of the third perforated block 207. A buckle 209 is installed at the round hole of the perforated locking rod 208. The top of the grooved ring 201 is pre-set with a second rectangular groove 210 and a third rectangular groove 212. The locking end of the L-shaped locking block 211 is located inside the grooved ring 201. The locking end of the L-shaped locking block 211 is adapted to the second rectangular groove 210 and the third rectangular groove 212.

[0029] In this embodiment, when it is necessary to replace one of the magnet actuators 104, the buckle 209 is removed from the perforated lever 208, and then the perforated lever 208 is removed from between the two perforated plates 204 and the third perforated block 207. Then, the grooved ring 201 is turned to the left. At this time, the rotating grooved ring 201 will drive the first perforated block 205, the second perforated block 206, and the third perforated block 207 to move simultaneously. When the second perforated block 206 has completely moved between the two perforated plates 204, the interior of the third rectangular groove 212 is just connected to the interior of the corresponding rectangular hole 202 and the interior of the corresponding first rectangular groove 203. At this time, moving one of the magnet actuators 104 will drive the connected L-shaped lever 211 to pass through the interior of the corresponding first rectangular groove 203, the interior of the third rectangular groove 212, and the interior of the corresponding rectangular hole 202 in sequence. When the L-shaped lever 211 has completely passed through the interior of the corresponding rectangular hole 202, one of the magnet actuators 104 is now complete. To disassemble another magnet driver 104 from the corresponding L-shaped bracket 103, first release the slotted ring 201 from its fixed state, then reverse the slotted ring 201 to connect the inside of the second rectangular groove 210 with the inside of the corresponding rectangular hole 202 and the inside of the corresponding first rectangular groove 203. Then move the other magnet driver 104. The moving magnet driver 104 will drive the connected L-shaped locking block 211 to pass through the inside of the corresponding first rectangular groove 203, the inside of the second rectangular groove 210, and the inside of the corresponding rectangular hole 202 in sequence. When the L-shaped locking block 211 has completely passed through the inside of the corresponding rectangular hole 202, the other magnet driver 104 can be disassembled from the corresponding L-shaped bracket 103. When both magnet drivers 104 need to be disassembled, repeat the above steps. That is, using this auxiliary mechanism 2, the magnet driver 104 can be quickly disassembled and assembled on the corresponding L-shaped bracket 103.

[0030] The overall effect and working principle of the mechanism are as follows: When it is necessary to clamp the wafer body 115, the wafer body 115 is first placed on the wafer chuck 109. Then, the two magnet drivers 104 are activated simultaneously, and their magnetic field directions are changed so that the top of the magnet driver 104 and the bottom of the corresponding main magnet 111 are in a state of like pole repulsion. That is, using the principle of magnetic force, the two main magnets 111 are completely pushed into the corresponding slots 114. When the two main magnets 111 are completely inside the corresponding slots 114, the tops of the two main magnets 111 are exactly inside the corresponding slots 113. At the same time, the top of each main magnet 111 is in a state of unlike pole attraction with the bottom of the corresponding magnet inside the wafer chuck 109. Then, through the spring inside the wafer chuck 109 in the initial state, the wafer chuck 109 is clamped. The synchronous drive disk inside the wafer chuck 109 is tightly fixed. When the synchronous drive disk inside the wafer chuck 109 is fixed, the magnetic levitation motor 101 is started. The magnetic levitation motor 101, when started, will drive the spindle 102 to rotate through the bottom stabilizing seat 106, the round tube 110 and the corresponding bearing. At the same time, the rotating spindle 102 will drive the top cover 108 to rotate through the round tube 110 and the top stabilizing seat 107. When the top cover 108 rotates, it will drive the first mounting ring 112 to rotate. The rotating first mounting ring 112 will drive the outer shell of the wafer chuck 109 to rotate. The rotating outer shell of the wafer chuck 109 will cooperate with the synchronous drive disk inside the wafer chuck 109, which is in a fixed state, and the connecting parts inside the wafer chuck 109 to drive the rotating clamping pin on the wafer chuck 109 to rotate, clamping the wafer body 115.

[0031] When it is necessary to remove the processed wafer body 115 from the wafer chuck 109, the outer shell of the wafer chuck 109 is reversed to the initial position, the wafer body 115 is then removed from the wafer chuck 109, and then the magnetic field direction of the two magnet drivers 104 is changed to magnetically reset the two main magnets 111 back to their original positions.

[0032] When it is necessary to replace one of the magnet actuators 104, the clip 209 is removed from the perforated lever 208, and then the perforated lever 208 is removed from between the two perforated plates 204 and the third perforated block 207. Then, the grooved ring 201 is turned counterclockwise. The rotating grooved ring 201 will cause the first perforated block 205, the second perforated block 206, and the third perforated block 207 to move simultaneously. When the second perforated block 206 is fully moved between the two perforated plates 204, the interior of the third rectangular groove 212 is now connected to the interior of the corresponding rectangular hole 202 and the interior of the corresponding first rectangular groove 203. Moving one of the magnet actuators 104 will cause the connected L-shaped lever 211 to pass sequentially through the interior of the corresponding first rectangular groove 203, the interior of the third rectangular groove 212, and the interior of the corresponding rectangular hole 202. When the L-shaped lever 211 has completely passed through the interior of the corresponding rectangular hole 202, this… One magnet driver 104 can be disassembled from the corresponding L-shaped bracket 103 at a time. When the other magnet driver 104 needs to be disassembled, the grooved ring 201 is first released from its fixed state. Then, the grooved ring 201 is reversed so that the inside of the second rectangular groove 210 is connected to the inside of the corresponding rectangular hole 202 and the inside of the corresponding first rectangular groove 203. Then, the other magnet driver 104 is moved. The moving magnet driver 104 will drive the connected L-shaped block 211 to pass through the inside of the corresponding first rectangular groove 203, the inside of the second rectangular groove 210, and the inside of the corresponding rectangular hole 202 in sequence. When the L-shaped block 211 has completely passed through the inside of the corresponding rectangular hole 202, the other magnet driver 104 can be disassembled from the corresponding L-shaped bracket 103. When both magnet drivers 104 need to be disassembled, the above steps are repeated.

[0033] The wafer chuck 109 consists of a top shell, a bottom shell, a synchronous drive disk, a connector, a rotary clamping pin, an open ring, a magnet, an L-shaped block, and a spring. The open ring is fixed to the bottom of the inner wall of the bottom shell. The synchronous drive disk is rotatably connected to the outer wall of the open ring via a bearing. The bottom shell and the top shell are installed together by screws. The synchronous drive disk is connected to the rotary clamping pin via the connector, and all three are rotatably connected to each other. Magnets are fixed inside the two mounting holes on the synchronous drive disk. One end of the L-shaped block is fixed to the bottom of the inner wall of the bottom shell, and a spring is fixed to the other end of the L-shaped block. At the same time, one end of the spring is fixed to the surface of the synchronous drive disk.

[0034] Among them, the magnetic levitation motor 101, the magnet driver 104, the wafer chuck 109 and the main magnet 111 are all technologies disclosed in this field, and their models can be selected according to the actual situation, so they will not be described in detail here.

[0035] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnetic drive device for semiconductor cleaning, comprising a magnetic drive mechanism (1), characterized in that: The magnetic transmission mechanism (1) is provided with an auxiliary mechanism (2). The magnetic transmission mechanism (1) includes a magnetic levitation motor (101). The magnetic levitation motor (101) has a main shaft (102) inside. The top of the magnetic levitation motor (101) is fixed with two symmetrical L-shaped frames (103). Each L-shaped frame (103) is provided with a magnet driver (104) on its surface. The top of the magnetic levitation motor (101) is fixed with a bottom stabilizing seat (106). The top of the main shaft (102) is fixedly connected to a top stabilizing seat (107). The top of the top stabilizing seat (107) is fixedly connected to a top cover (108). A round tube is installed on the top of the bottom stabilizing seat (106). (110) A first mounting ring (112) is placed on the top of the circular tube (110). A wafer chuck (109) is installed on the top of the first mounting ring (112). A support plate (105) is fixedly sleeved on the outer wall of the circular tube (110) near the top. A main magnet (111) is magnetically attracted to the top of each magnet driver (104). A second mounting ring (116) is movably sleeved on the outer wall of the first mounting ring (112). Two symmetrical slots (113) are preset at the bottom of the second mounting ring (116). Two slot holes (114) are preset at the bottom of the support plate (105). A wafer body (115) is movably clamped on the wafer chuck (109).

2. The magnetic drive device for semiconductor cleaning according to claim 1, characterized in that: The magnetic levitation motor (101) is used to drive the main shaft (102) to rotate, the magnet driver (104) is used to control the movement of the main magnet (111), the main shaft (102) is rotatably connected to the inside of the round tube (110) through the bearing, the top of the top cover (108) is movably sleeved inside the top middle through hole of the wafer chuck (109), and the bottom of the second mounting ring (116) is fixed to the top of the support plate (105).

3. The magnetic drive device for semiconductor cleaning according to claim 1, characterized in that: The interior of each slot (113) is connected to the interior of each hole (114), the top of each main magnet (111) is located inside each hole (114), the second mounting ring (116) is located inside the top groove of the wafer chuck (109), and the first mounting ring (112) is fixedly sleeved on the top outer surface of the top cover (108).

4. The magnetic drive device for semiconductor cleaning according to claim 1, characterized in that: The auxiliary mechanism (2) includes a grooved ring (201), and each of the two L-shaped frames (103) has a first rectangular groove (203) on its opposite side. Each of the two L-shaped frames (103) has a rectangular hole (202) on its opposite side. The interior of each rectangular hole (202) is connected to the interior of each first rectangular groove (203).

5. The magnetic drive device for semiconductor cleaning according to claim 4, characterized in that: The grooved ring (201) is rotatably connected between the interiors of the two first rectangular grooves (203). Each of the two magnet actuators (104) has an L-shaped locking block (211) fixed on its opposite side. Each L-shaped locking block (211) is movably fitted between the interior of the corresponding rectangular hole (202) and the interior of the corresponding first rectangular groove (203).

6. The magnetic drive device for semiconductor cleaning according to claim 5, characterized in that: Two perforated plates (204) are fixed to the surface of one of the L-shaped frames (103). A first perforated block (205), a second perforated block (206), and a third perforated block (207) are fixed to the outer wall of the grooved ring (201). A perforated clamping rod (208) is provided between the interior of the two perforated plates (204) and the interior of the third perforated block (207).

7. The magnetic drive device for semiconductor cleaning according to claim 6, characterized in that: The perforated lever (208) has a buckle (209) installed at the round hole. The top of the grooved ring (201) is pre-set with a second rectangular groove (210) and a third rectangular groove (212). The snap-fit ​​end of the L-shaped snap-fit ​​block (211) is located inside the grooved ring (201). The snap-fit ​​end of the L-shaped snap-fit ​​block (211) is adapted to the second rectangular groove (210) and the third rectangular groove (212).

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