Upper electrode assembly

Abstract

The present disclosure relates to an upper electrode assembly. The upper electrode assembly includes a bushing assembly fastened to an insertion hole of a plasma electrode plate, and a lifting rod received in a receiving space of an electrode support plate, and configured to detachably couple the plasma electrode plate to the electrode support plate. The bushing assembly includes a bushing configured to be coupled to the lift rod. The lift rod includes a coupling portion configured to couple with the bushing. The coupling portion includes: a bush insertion groove into which the bush is inserted; a first path configured to allow the lift rod to move in an axial direction when the bush is inserted; and a second path configured to allow the lift lever to rotate if the bushing is positioned at an end of the first path.

Description

Technical Field

[0001] This disclosure relates to an upper electrode assembly, and more specifically to an upper electrode assembly configured to enhance the connection force and achieve quick and easy fastening when connecting a plasma electrode plate to an electrode support plate using a lifting rod. Background Technology

[0002] Semiconductor devices can be manufactured through various processes. For example, semiconductor devices can be manufactured by performing photolithography, etching, and deposition processes on a wafer made of silicon or the like. In each process of manufacturing a semiconductor device, materials in a plasma state may be used. During the use of plasma, electrodes for generating and controlling the plasma can be used in semiconductor manufacturing equipment. The electrodes for plasma can be located at the bottom and top of the chamber, respectively. Electrodes for plasma can be formed by combining multiple components.

[0003] Conventionally, to secure plasma plates to the device, a fastening structure is typically used that combines electrode plates with insertion grooves, bushings, and fastening components (e.g., bolts). However, such fastening structures can result in poor operability during the tightening and loosening of plasma electrode plates and can also cause problems such as reduced flatness or adhesion of the electrode plates due to unbalanced tightening forces. Summary of the Invention

[0004] This disclosure provides an upper electrode assembly based on a lifting rod that improves the operability of fastening and loosening the plasma electrode plate to and from the device while maintaining a consistent fastening force, thereby solving the aforementioned problems.

[0005] Embodiments of this disclosure may provide an upper electrode assembly including a bushing assembly and a lifting rod, the bushing assembly being fastened to an insertion hole of a plasma electrode plate, the lifting rod being received in a receiving space of an electrode support plate, and the lifting rod being configured to detachably connect the plasma electrode plate to the electrode support plate.

[0006] The bushing assembly may include a bushing configured to be coupled to the lifting rod. The lifting rod may include a coupling portion configured to be coupled to the bushing. The coupling portion may include: a bushing insertion groove into which the bushing is inserted; a first path configured to allow axial movement of the lifting rod when the bushing is inserted; and a second path configured to allow rotation of the lifting rod when the bushing is positioned at the end of the first path. Attached Figure Description

[0007] Figure 1 This is a partial exploded perspective view of the upper electrode assembly according to an embodiment of the present disclosure.

[0008] Figure 2 This is an assembly view of the upper electrode assembly according to an embodiment of the present disclosure.

[0009] Figure 3A This is a cross-sectional view of an assembled upper electrode assembly according to an embodiment of the present disclosure.

[0010] Figure 3B This is a cross-sectional view of another assembled upper electrode assembly according to an embodiment of the present disclosure.

[0011] Figure 4A These are perspective and enlarged views of a lifting rod according to an embodiment of the present disclosure.

[0012] Figure 4B This is a left perspective view of the lifting rod according to an embodiment of the present disclosure.

[0013] Figure 4C This is a bottom perspective view of the lifting rod according to an embodiment of the present disclosure.

[0014] Figure 4D This is a bottom view of the lifting rod according to an embodiment of the present disclosure.

[0015] Figure 4E This is a right-side view of the lifting rod according to an embodiment of the present disclosure.

[0016] Figure 4F This is a top view of the lifting rod according to an embodiment of the present disclosure.

[0017] Figure 4G This is a left-side view of the lifting rod according to an embodiment of the present disclosure.

[0018] Figure 4H This is a front view of the lifting rod according to an embodiment of the present disclosure.

[0019] Figure 5A This is a perspective view of a bushing assembly in an assembled state according to an embodiment of the present disclosure.

[0020] Figure 5B This is a cross-sectional view of a bushing assembly in an assembled state according to an embodiment of the present disclosure.

[0021] Figure 5C This is an exploded view of a bushing assembly according to an embodiment of the present disclosure.

[0022] Figure 5D A perspective view of a bushing according to another embodiment of the present disclosure is shown.

[0023] Figure 6This is a perspective view of an electrode support plate that also includes rib insertion grooves according to an embodiment of the present disclosure.

[0024] Figure 7 This is a perspective view of an upper electrode assembly including a lifting rod guide unit in an assembled state according to an embodiment of the present disclosure.

[0025] Figure 8 This is a cross-sectional view of an upper electrode assembly including a lifting guide unit in an assembled state according to an embodiment of the present disclosure.

[0026] Figure 9A This is a perspective view of a lifting rod guide unit according to an embodiment of the present disclosure.

[0027] Figure 9B This is a bottom view of the lifting rod guide unit according to an embodiment of the present disclosure.

[0028] Figure 10A This is an exploded perspective view of a portion of the upper electrode assembly according to an embodiment of the present disclosure.

[0029] Figures 10B to 10E This is a perspective view showing the fastening process according to embodiments of the present disclosure.

[0030] Figure 10F A front view showing a fastening process according to an embodiment of the present disclosure. Detailed Implementation

[0031] To fully understand the configurations and effects of this disclosure, some embodiments will be described with reference to the accompanying drawings. However, this disclosure is not limited to the following exemplary embodiments and can be implemented in various forms. Exemplary embodiments are provided merely to illustrate this disclosure and to enable those skilled in the art to fully understand its scope.

[0032] In this specification, when an element is described as being "on" another element, the element may be directly on the other element, or there may be one or more intervening elements. In the drawings, certain thicknesses may be exaggerated to better illustrate the technical details. Throughout the specification, the same reference numerals denote the same elements.

[0033] The embodiments described herein may be illustrated using perspective views, sectional views, and / or plan views, which are presented as idealized examples of this disclosure. For clarity, the thickness of layers and regions in the drawings may be exaggerated. The regions shown in the drawings are for illustrative purposes and should not be construed as limiting the scope of this disclosure. Although terms such as “first,” “second,” and “third” may be used to describe various elements, these terms are for distinction only and do not imply any particular order or hierarchy. The embodiments described and illustrated herein include complementary variations.

[0034] The terminology used in this specification is for illustrative purposes only and is not intended to limit this disclosure. Unless otherwise expressly stated, the singular form may also include the plural form. The terms "comprising / including" and "having / with" do not exclude the presence or addition of one or more other components.

[0035] refer to Figure 1 and Figure 2 According to embodiments of the present disclosure, the upper electrode assembly 10 may include an electrode support plate 100, a plasma electrode plate 200, a lifting rod 300, and a bushing assembly 400.

[0036] The upper electrode assembly 10 can be installed in a chamber for processing or procedures using plasma. For example, the upper electrode assembly 10 can be installed in a chamber for semiconductor etching. More specifically, the upper electrode assembly 10 can be an electrode installed above and spaced apart from a lower electrode within the etching chamber.

[0037] The electrode support plate 100 can serve as an upper structural component of the device and can be formed as a disc-shaped structure. An opening 110 for inserting the lifting rod 300 can be formed on the side of the electrode support plate 100. A through groove 120 can be formed on the lower portion of the electrode support plate 100. The through groove 120 can receive a bushing assembly 400 inserted into and secured to the plasma electrode plate 200. A receiving space 130 can be formed inside the electrode support plate 100. The receiving space 130 can be configured to accommodate components such as the lifting rod 300 and the bushing assembly 400. The receiving space 130 can have a three-dimensional shape, such as a cuboid or cylinder, but is not limited to such shapes.

[0038] The plasma electrode plate 200 may comprise a ceramic material, such as silicon, silicon carbide, alumina, or quartz. The plasma electrode plate 200 may be formed into a disk-shaped structure. Furthermore, the upper surface of the plasma electrode plate 200 may be formed flat to ensure close contact with the electrode support plate 100.

[0039] An insertion hole 210 can be formed on the plasma electrode plate 100, penetrating the upper surface of the plasma electrode plate 200. A bushing assembly 400 can be inserted into the insertion hole 210. The bushing assembly 400 can be inserted into the insertion hole 210 to mechanically connect the plasma electrode plate 200 to the upper electrode support plate 100. Multiple insertion holes 210 can be provided. The multiple insertion holes 210 can be spaced apart from each other in the circumferential direction. Multiple bushing assemblies 400 can be provided. For example, the number of bushing assemblies 400 can correspond to the number of insertion holes 210. Multiple bushing assemblies 400 can be inserted into multiple insertion holes 210 respectively.

[0040] The plasma electrode plate 200 may include a plurality of nozzles disposed on the surface of the plasma electrode plate 200. The nozzles may be configured to supply process gas. For example, the plasma electrode plate 200 may be a shower head.

[0041] The plasma electrode plate 200 may also include multiple micropores. The micropores can allow process gases to pass through, but are not limited to this.

[0042] Figure 3A This illustrates an embodiment of the present disclosure in such a state as Figure 2 A cross-sectional view of the upper electrode assembly 10 in its assembled state, taken along line A-A'. Figure 3B This is a cross-sectional view showing a section taken along line A-A' of the upper electrode assembly 10 in an assembled state according to another embodiment of the present disclosure. Figures 4A to 4H These are perspective views and plan views showing the lifting rod 300 from different directions. Figures 5A to 5D These are views showing the assembled and disassembled states of the bushing assembly 400. Referring to these figures, the structural shapes of the lifting rod 300 and the bushing assembly 400, and their connection relationships, can be understood in more detail.

[0043] refer to Figure 3A and Figures 5A to 5C According to embodiments of the present disclosure, the bushing assembly 400 may include a bushing 410, a washer 420, and a bushing fastening member 430. The bushing 410 may include a bushing body 412, a bushing head 411, and a fastening portion 413.

[0044] A fastening portion 413 may be formed at the lower portion of the bushing body 412. The fastening portion 413 may be disposed in the insertion hole 210 of the plasma electrode plate 200. The fastening portion 413 may be fastened in the insertion hole 210 by a bushing fastening member 430. When the bushing 410 is fastened to the plasma electrode plate 200, a washer 420 may be placed between the fastening portion 413 and the bushing fastening member 430. The washer 420 placed between the fastening portion 413 and the bushing fastening member 430 may be used to maintain the fastening height, ensure fastening force, and absorb vibration. Multiple washers 420 may be provided.

[0045] The bushing body 412 may be formed to extend upward from the fastening portion 413. The bushing body 412 may be inserted into the receiving space 130 through the through groove 120 of the electrode support plate 100. The bushing body 412 may have a cylindrical shape or the like, and may be inserted into the bushing insertion groove 311 of the connecting portion 310 of the lifting rod 300.

[0046] A spherical or disc-shaped bushing head 411 may be formed on the upper portion of the bushing body 412, but is not limited thereto. The bushing head 411 may have a larger diameter than the bushing body 412. The bushing head 411 may be inserted into the receiving space 130 through the through groove 120 of the electrode support plate 100. Furthermore, the bushing head 411 may be inserted into the bushing insertion groove 311 of the connecting portion 310 of the lifting rod 300. When the plasma electrode plate 200 is fastened to the electrode support plate 100, the bushing head 411 may be positioned on the upper portion of the bushing fixing portion 340 of the lifting rod 300.

[0047] refer to Figure 3B and Figure 5D The bushing 410 may also include a protrusion 415 formed to project from the bushing body 412. The fastening portion 413 may also include a support 414. The support 414 may be formed at the lowermost end of the fastening portion 414. The support 414 may be in close contact with the bottom surface of the insertion hole 210. The protrusion 415 may be in the form of a disc or a ball, but is not limited thereto. The protrusion 415 may have a larger diameter than the bushing head 411, and the protrusion 415 may have a smaller diameter than the support 414 located at the lowermost end of the fastening portion 413. The protrusion 415 may be formed at the lower portion of the bushing body 412. The protrusion 415 may interfere with other components of the upper electrode assembly 10, such as the lifting rod 300. Details of the protrusion 415 will be described below.

[0048] refer to Figure 3A and Figure 3B According to embodiments of the present disclosure, the lifting rod 300 can be inserted through the opening 110 of the electrode support plate 100 and received in the receiving space 130. The lifting rod 300 can be used to detachably connect the plasma electrode plate 200 to the electrode support plate 100. The lifting rod 300 can be arranged to contact the upper surface of the lower portion of the receiving space 130 to provide a uniform clamping force and ensure adhesion and flatness of the plasma electrode plate 200. The lifting rod 300 can be formed in a cylindrical shape, etc.

[0049] refer to Figures 3A to 4H The lifting rod 300 may include a connecting portion 310, an operating portion 320, a main body portion 330, a bushing fixing portion 340, and a lifting portion 350. The operating portion 320 may be arranged adjacent to the opening 110 of the electrode support plate 100. The lifting rod 300 can be axially moved and rotated within the receiving space 130 via the operating portion 320. The axial direction may be from the opening 110 of the electrode support plate 100 toward the center of the electrode support plate 100. The lifting rod 300 is capable of moving along the axial direction. The axial direction may be exemplarily represented as... Figure 2The direction A-A' is shown in the diagram. The main body portion 330 can be formed in the shape of a rod extending along the axial direction of the lifting rod 300. The main body portion 330 can serve as a structural center supporting the axial movement and rotation of the lifting rod 300. The main body portion 330 can have a cylindrical shape, etc., but is not limited thereto. Multiple main body portions 330 can be provided.

[0050] The connecting portion 310 may be the area where the lifting rod 300 connects to the bushing assembly 400, and the connecting portion 310 may include a bushing insertion groove 311, a first path 312, and a second path 313. The connecting portion 310 may have a cylindrical shape, etc., but is not limited thereto. Multiple connecting portions 310 may be provided. The main body portion 330 may be disposed among multiple connecting portions 310.

[0051] refer to Figures 3A to 4H According to embodiments of the present disclosure, the lifting portion 350 may protrude from the side surface of the connecting portion 310, but is not limited thereto. The lifting portion 350 may have a semi-circular shape, etc., but is not limited thereto. When the lifting rod 300 rotates, the lifting portion 350 may contact the lower surface of the electrode support plate 100. As the lifting portion 350 contacts the lower surface of the electrode support plate 100, it can lift the rod 300 upward from below the electrode support plate 100.

[0052] Figure 4H This is a front view of the lifting rod 300, showing the lifting portion 350 protruding from the connecting portion 310. The diameter L2 of the connecting portion 310, including the lifting portion 350, can be larger than the diameter L1 of the main body portion 330. When the lifting rod 300 rotates, the lifting portion 350 can contact the lower surface of the electrode support plate 100, thereby lifting the lifting rod 300 upward. In this case, the height to which the lifting rod 300 rises can correspond to the difference between the diameter L2 of the connecting portion 310 including the lifting portion 350 and the diameter L1 of the main body portion 330. As the lifting rod 300 rises upward, the plasma electrode plate 200 can come into close contact with and be secured to the lower surface of the electrode support plate 100.

[0053] refer to Figure 3BAccording to another embodiment of this disclosure, the lifting portion 350 can be formed to protrude from the side surface of the main body portion 330. In this case, the height to which the lifting rod 300 rises can correspond to the difference between the diameter L1 of the main body portion 330 including the lifting portion 350 and the diameter L2 of the connecting portion 310. In one embodiment, the protrusion 415 can be formed on the lower portion of the bushing body 412 at a height equal to or less than the lifting height by which the lifting rod 300 rises from the lower surface of the electrode support plate 100. Therefore, the protrusion 415 can limit the lifting height of the lifting rod 300 achieved via the lifting portion 350.

[0054] The bushing 410 of the bushing assembly 400 can be inserted into the bushing insertion groove 311. For example, the bushing body 412 and the bushing head 411 of the bushing 410 can be inserted into the bushing insertion groove 311.

[0055] The first path 312 can be used to allow the lifting rod 300 to move in the axial direction when the bushing 410 is inserted into the bushing insertion groove 311. The first path 312 formed in the connecting portion 310 can be configured to allow the bushing body 412 to travel through the first path 312. The first path 312 can have an open or through structure extending in the axial direction of the lifting rod 300.

[0056] The second path 313 can be continuously formed from the end of the first path 123, and the second path 313 can have a structure such as a fan shape or a curved shape. The second path 313 can be configured to allow the bushing body 412 to travel through the second path 313. When the bushing 410 is positioned at the end of the first path 312, the second path 313 can allow the lifting rod 300 to rotate. As the lifting rod 300 performs the rotation operation, the second path 313 can be used to guide the bushing head 411 to be positioned above the bushing fixing portion 340.

[0057] The bushing retaining portion 340 can be configured to stably maintain the fastened state between the lifting rod 300 and the bushing assembly 400 by supporting the lower surface of the bushing head 411 when the lifting rod 300 is in the rotating position. The bushing retaining portion 340 can also remain fixed to prevent the lifting rod 300 from rotating in the opposite direction.

[0058] refer to Figures 6 to 9B According to embodiments of the present disclosure, the upper electrode assembly 10 may further include a lifting rod guide unit 500. The lifting rod guide unit 500 may be disposed within the receiving space 130 of the electrode support plate 100. The lifting rod guide unit 500 may be used to guide the lifting rod 300 so that the lifting rod 300 can be inserted into a predetermined position.

[0059] The lifting rod guide unit 500 may include a lifting rod guide 510, a bushing head insertion portion 520, and a bushing head fixing portion 530. The lifting rod guide 510 provides an insertion space to guide the lifting rod 300 into a predetermined position.

[0060] The lifting rod guide 510 can guide the axial movement and rotational positioning of the lifting rod 300 for precise alignment within the receiving space 130 of the electrode support plate 100. The lifting rod guide 510 can be formed in the shape of a cuboid housing with a bottom opening, but is not limited thereto. Furthermore, the lifting rod guide 510 may also include ribs 540 projecting from its outer surface, and these ribs 540 can be inserted into rib insertion grooves 140 formed on the side surface of the receiving space 130 of the electrode support plate 100, so that the entire lifting rod guide unit 500 can be held precisely fixed within the device.

[0061] The bushing head insertion portion 520 and the bushing head fixing portion 530 can be disposed on the upper surface of the lifting rod guide 510. The bushing head insertion portion 520 and the bushing head fixing portion 530 can be formed in a circular shape or the like, but are not limited thereto. When the upper electrode assembly 10 also includes the lifting rod guide unit 500, the bushing head 411 can be positioned on top of the bushing head insertion portion 520 and the bushing head fixing portion 530.

[0062] refer to Figures 10A to 10F The fastening process of the upper electrode assembly 10 according to embodiments of the present disclosure can be understood in more detail. Figure 10A This is an exploded perspective view showing a portion of the upper electrode assembly 10 according to an embodiment of the present disclosure. Figures 10B to 10F This is a sequential view showing the process by which the plasma electrode plate 200 into which the bushing assembly 400 is inserted comes into close contact with and is secured to the electrode support plate 100 by the axial movement and rotation of the lifting rod 300.

[0063] refer to Figure 10A According to embodiments of the present disclosure, the upper electrode assembly 10 may include a lifting rod 300. The lifting rod 300 can be inserted through an opening 110 in the electrode support plate 100 and is received within a receiving space 130. In this state, a bushing assembly 400 coupled to the plasma electrode plate 200 can be inserted into a through groove 120 in the electrode support plate 100 and then into a bushing insertion groove 311 in the lifting rod 300.

[0064] refer to Figure 10BWith the bushing assembly 400 inserted into the bushing insertion groove 311 of the lifting rod 300, the lifting rod 300 can be moved axially by manipulating the operating portion 320. The first path 312 formed in the connecting portion 310 of the lifting rod 300 can be configured as an opening structure that allows the bushing 410 to pass through, and can be used to guide the axial movement of the lifting rod 300.

[0065] refer to Figures 10C to 10F When the lifting rod 300 moves axially to position the bushing 410 at the end of the first path 312, the lifting rod 300 can be rotated by manipulating the operating part 320. As the lifting rod 300 rotates, the bushing 410 can travel through the second path 313. The second path 313 can guide the bushing 410 to be positioned at the bushing fixing part 340. Furthermore, the second path 313 can guide the bushing head 411 to be positioned above the bushing fixing part 340.

[0066] As the lifting rod 300 rotates, the lifting portion 350 protruding from the connecting portion 310 contacts the lower surface of the electrode support plate 100, thereby lifting the lifting rod 300 from the lower surface of the electrode support plate 100. The lifting rod 300 can be raised to a height corresponding to the difference between the diameter L2 of the connecting portion 310 including the lifting portion 350 and the diameter L1 of the main body portion 330. As the lifting rod 300 is lifted upward, the bushing 410 can be positioned at the bushing fixing portion 340. When the rotation operation is completed, the bushing fixing portion 340 can be positioned below and support the bushing head 411, thereby allowing the plasma electrode plate 200 to come into close contact with and be secured to the lower surface of the electrode support plate 100.

[0067] The upper assembly according to this disclosure improves the operability of assembling and disassembling the plasma electrode plate and the electrode support plate using the aforementioned components. Furthermore, it ensures uniform clamping force and maintains close contact and flatness of the plasma electrode plate. In other words, by improving the ease of replacing the plasma electrode plate in the upper electrode assembly and enhancing the structural stability of the upper electrode assembly, product quality and cost-effectiveness can be ensured.

[0068] According to embodiments of this disclosure, the upper electrode assembly includes a lifting rod with a lifting function that is axially movable and subsequently rotated, thereby enabling the plasma electrode plate to be quickly and reliably assembled to or detached from the electrode support plate without the use of separate tools.

[0069] By using lifting rods to fasten the plasma electrode plates to the electrode support plates, uniform fastening force can be ensured, and the close contact and flatness of the plasma electrode plates can be maintained.

[0070] According to embodiments of this disclosure, the upper electrode assembly allows the bushing assembly and the lifting rod to be secured along their respective insertion grooves and paths, thereby minimizing assembly errors of the device.

[0071] Furthermore, the fixing structure between the bushing assembly and the lifting rod improves mechanical stability by preventing movement of the lifting rod after tightening. When a lifting rod guide unit is included, the insertion direction and alignment of the lifting rod can be guided more precisely.

[0072] While this disclosure has been described with reference to preferred embodiments, it should be understood that these embodiments are provided for illustrative purposes only and do not limit the scope of this disclosure. Various modifications and equivalent arrangements may be made without departing from the spirit and scope of the appended claims. Therefore, the described embodiments should be considered as examples of this disclosure and not as limitations.

[0073] Cross-references to related applications

[0074] This application claims priority and benefit to Korean Patent Application No. 10-2024-0062656, filed May 13, 2024; Korean Patent Application No. 10-2024-0112147, filed August 21, 2024; and Korean Patent Application No. 10-2025-0055371, filed April 28, 2025, the entire contents of which are incorporated herein by reference.

[0075] Explanation of reference numerals in the attached figures

[0076] 10: Upper electrode assembly

[0077] 100: Electrode support plate

[0078] 110: Opening

[0079] 120: Through groove

[0080] 130: Acceptance Space

[0081] 140: Rib insertion groove

[0082] 200: Plasma electrode plate

[0083] 210: Insertion hole

[0084] 300: Lifting rod

[0085] 310: Connecting parts

[0086] 311: Bushing insertion groove

[0087] 312: First Path

[0088] 313: Second Path

[0089] 320: Operation Section

[0090] 330: Main Body

[0091] 340: Bushing fixing part

[0092] 350: Upgraded Section

[0093] 400: Bushing assembly

[0094] 410: Bushing

[0095] 411: Bushing Head

[0096] 412: Bushing Body

[0097] 413: Fastening parts

[0098] 414: Support component

[0099] 415: Protrusion

[0100] 420: Washer

[0101] 430: Bushing fastening component

[0102] 500: Lifting rod guide unit

[0103] 510: Lifting rod guide

[0104] 520: Bushing head insertion part

[0105] 530: Bushing head fixing part

[0106] 540: Ribs

[0107] L1: Diameter of the main body

[0108] L2: Diameter of the connecting part.

Claims

1. An upper electrode assembly, comprising: A bushing assembly, the bushing assembly being fastened to an insertion hole in a plasma electrode plate; and A lifting rod is housed within a receiving space of an electrode support plate, and the lifting rod is configured to detachably connect the plasma electrode plate to the electrode support plate. The bushing assembly includes a bushing configured to connect with the lifting rod. The lifting rod includes a connecting portion for engaging the bushing, and The connecting portion includes: A bushing insertion groove is provided, wherein the bushing is inserted into the bushing insertion groove. A first path, configured to allow the lifting rod to move axially when the bushing is inserted; and A second path is configured to allow the lifting rod to rotate when the bushing is positioned at the end of the first path.

2. The upper electrode assembly according to claim 1, wherein the bushing assembly further comprises: A bushing fastening member for fastening the bushing to the insertion hole of the plasma electrode plate; and A washer, wherein the washer is positioned between the bushing fastener and the bushing. The bushing includes: A fastening portion, wherein the fastening portion is disposed in the insertion hole of the plasma electrode plate; and A bushing body, the bushing body protruding from the fastening portion and configured to pass through the lifting rod; and A bushing head is formed on the upper portion of the bushing body and is configured to be fixed to the lifting rod.

3. The upper electrode assembly of claim 2, wherein the bushing further includes a protrusion formed to project from the bushing body. The fastening portion includes a support formed at the lowermost end of the fastening portion, and The diameter of the protrusion is larger than the diameter of the bushing head and smaller than the diameter of the support member.

4. The upper electrode assembly according to claim 2, wherein the electrode support plate comprises: An opening is formed on the side of the electrode support plate, and the lifting rod is inserted into the opening; and A through groove is formed at the lower part of the electrode support plate, and the bushing body and the bushing head are inserted into the through groove.

5. The upper electrode assembly according to claim 1, wherein the lifting rod further comprises: The operating part is configured to manipulate the axial movement and rotation of the lifting rod; and The main body portion is in the form of a rod extending along the axial direction.

6. The upper electrode assembly of claim 5, wherein the operating portion is disposed at the end of the lifting rod adjacent to the opening. The connecting portion includes multiple connecting portions, and The main body portion is disposed between the plurality of connecting portions.

7. The upper electrode assembly of claim 5, wherein the lifting rod further comprises a lifting portion formed in the connecting portion or formed in the main body portion, and The lifting portion is configured to lift the lifting rod from below the electrode support plate during rotation of the lifting rod.

8. The upper electrode assembly of claim 2, wherein the lifting rod further comprises a bushing fixing portion, the bushing fixing portion being configured to fix the bushing head and the lifting rod in a state of rotation of the lifting rod, and The bushing fixing portion is located below the bushing head to support the bushing head.

9. The upper electrode assembly according to claim 1, further comprising: A lifting rod guide unit is disposed in the receiving space of the electrode support plate. The lifting rod guide unit includes a lifting rod guide configured to receive the lifting rod.

10. The upper electrode assembly of claim 9, wherein the lifting rod guide unit further comprises: A bushing head insertion portion, the bushing head insertion portion being configured to receive the bushing head; and A bushing head fixing portion is configured to fix the bushing head.

11. The upper electrode assembly of claim 10, wherein the lifting rod guide further includes a rib projecting from the side of the lifting rod guide, and The receiving space of the electrode support plate includes a rib insertion groove into which the rib is inserted.

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