Lower electrode assembly, plasma processing device and method for preventing arc discharge

Abstract

The present invention provides a lower electrode assembly for preventing arc discharge, disposed within a vacuum reaction chamber. The assembly comprises: a base for supporting a wafer and serving as the center electrode of the lower electrode assembly; an RF power supply for providing a first RF signal to the center electrode; a ring component surrounding the center electrode; an edge electrode disposed within the ring component and electrically insulated from the center electrode; and an edge electrode feed assembly for providing a second RF signal to the edge electrode. The edge electrode feed assembly comprises: a conductive core and a conductive shielding layer disposed around the outer periphery of the conductive core, an insulating layer filling the space between the conductive core and the conductive shielding layer, and electrically connected to the center electrode. A gap is defined between the conductive shielding layer and the inner wall of a channel housing the edge electrode feed assembly to accommodate thermal expansion and contraction of the channel or dimensional mismatches caused by mechanical errors resulting from the combination of surrounding components. The present invention also provides a plasma processing apparatus and a method for preventing arc discharge in the lower electrode assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor equipment, and in particular to a lower electrode assembly, a plasma processing device and a method for preventing arc discharge. Background Art

[0002] In the field of semiconductor manufacturing technology, it is often necessary to perform plasma treatment on a wafer to be processed within a plasma processing apparatus. A plasma processing apparatus comprises a vacuum reaction chamber containing a lower electrode. The lower electrode comprises a base and a facility plate disposed beneath the base, with the base and facility plate serving as a central electrode. The base includes an electrostatic chuck for placing the wafer to be processed. Reactive gas is fed into the reaction chamber, and one or more radio frequency (RF) power supplies can be individually applied to the lower electrode to deliver RF power to the lower electrode, thereby generating an RF electric field within the reaction chamber. Most of the electric field is contained within the processing region above the wafer to be processed. This electric field accelerates a small number of electrons within the reaction chamber, causing them to collide with gas molecules of the input reactive gas. These collisions lead to ionization of the reactive gas and excitation of the plasma, thereby generating a plasma within the reaction chamber. Finally, chemical reactions and / or physical interactions (such as etching, deposition, etc.) occur between the plasma and the wafer, forming various characteristic structures.

[0003] Due to the discontinuity of space and materials between the electrostatic chuck and surrounding process components, or due to the dimensional changes of process components caused by plasma erosion over time, the edge effect caused by the discontinuous feeding of edge RF energy will cause differences in the processing effects inside and outside the wafer, which may lead to a decrease in wafer yield or even scrapping in severe cases. One way to improve the edge effect is to configure an edge electrode around the electrostatic chuck (center electrode) and feed part of the RF energy to the edge electrode to adjust and compensate for the edge effect. As the accuracy of the etching process continues to improve, the voltage of the RF power supply applied to the lower electrode continues to increase. When the RF voltage applied to the lower electrode increases, arc discharge is likely to occur between the lower electrode and the edge electrode, which not only loses RF energy but also damages the components in the reaction chamber. Summary of the Invention

[0004] The object of the present invention is to provide a lower electrode assembly, a plasma processing device and a method for preventing arc discharge. The lower electrode assembly of the present invention adopts an edge electrode feeding assembly to feed power to the edge electrode, and the edge electrode feeding assembly includes a conductive core, a conductive shielding layer surrounding the outer periphery of the conductive core, and an insulating layer filled between the conductive core and the conductive shielding layer. There is no gap between the insulating layer and the conductive core and the conductive shielding layer, which can prevent the conductive core and the conductive shielding layer from generating an RF voltage difference in the RF field space, thereby avoiding arc discharge between the conductive core and the conductive shielding layer. There is a gap between the conductive shielding layer and the inner wall of the channel that accommodates the edge electrode feeding assembly. By maintaining an electrical connection between the conductive shielding layer and the inner wall of the channel, arc discharge is prevented from occurring in the gap. The present invention can not only avoid RF energy loss, but also prevent arc discharge from damaging components in the vacuum reaction chamber.

[0005] In order to achieve the above object, the present invention provides a lower electrode assembly for preventing arc discharge, which is arranged in a vacuum reaction chamber, and the lower electrode assembly comprises:

[0006] a base, for supporting the wafer and serving as a central electrode of the lower electrode assembly;

[0007] a radio frequency power supply, configured to provide a first radio frequency signal to the central electrode;

[0008] a ring member surrounding the central electrode;

[0009] an edge electrode surrounding the central electrode and electrically insulated from the central electrode;

[0010] an edge electrode feeding assembly, configured to provide a second radio frequency signal to the edge electrode;

[0011] The edge electrode feeding assembly comprises: a conductive core and a conductive shielding layer arranged around the outer periphery of the conductive core, an insulating layer is filled between the conductive core and the conductive shielding layer, and the conductive shielding layer is electrically connected to the central electrode;

[0012] There is a gap between the conductive shielding layer and the inner wall of the channel accommodating the edge electrode feeding assembly to accommodate thermal expansion and contraction of the channel or size mismatch caused by the combination of surrounding components due to mechanical errors.

[0013] Optionally, there is no gap between the insulating layer and the conductive core and the conductive shielding layer.

[0014] Optionally, the edge electrode feeding assembly further includes: a plurality of conductive connecting members, which are arranged in the channel and electrically connect the conductive shielding layer and the central electrode.

[0015] Optionally, the connecting member is at least one of a bolt, a spring, and a conductive gasket.

[0016] Optionally, the material of the connecting piece includes at least one of aluminum, gold, silver, copper, and titanium.

[0017] Optionally, the lower electrode assembly for preventing arc discharge further includes a facility plate, which is arranged at the bottom of the base, and the central electrode includes the facility plate and the base.

[0018] Optionally, the conductive core is a flexible conductive wire or a hard conductive rod.

[0019] Optionally, the edge electrode feeding assembly is electrically connected to a corresponding radio frequency power supply via an edge impedance adjustment unit; and the edge electrode potential is adjusted via the edge impedance adjustment unit.

[0020] Optionally, the second RF power supply is electrically connected to the edge electrode feeding assembly via an edge impedance adjustment unit; and the edge electrode potential is adjusted via the edge impedance adjustment unit.

[0021] Optionally, the insulating layer is made of any one of Teflon, glass, and ceramic.

[0022] Optionally, the outer surface of the conductive shielding layer contains Al2O3 formed by plating.

[0023] Optionally, the ring component includes: a focusing ring, which is arranged around the outer circumference of the base to control the distribution of the radio frequency electric field at the edge of the wafer to be processed.

[0024] Optionally, the ring component further includes: a cover ring, which is arranged around the outer circumference of the focusing ring to prevent plasma in the vacuum reaction chamber from corroding various components below the cover ring.

[0025] Optionally, the ring component further includes: a grounding ring, which is arranged around the outer periphery of the base and located below the cover ring; a radio frequency loop is formed between the plasma in the reaction chamber and the ground through the grounding ring.

[0026] Optionally, the ring component further includes: an insulating ring, which is located below the focusing ring; an edge electrode embedded in the insulating ring, or located between the insulating ring and the focusing ring; and the insulating ring is used to prevent discharge between the center electrode and the grounding ring.

[0027] Optionally, the second RF signal is connected to the RF power supply of the first RF signal or to an independent RF power supply.

[0028] Optionally, the channel accommodating the edge electrode feed assembly passes through the center electrode or a component outside the center electrode.

[0029] Optionally, the edge electrode feeding assembly is a one-stage or segmented edge electrode feeding assembly; the segments of the segmented edge electrode feeding assembly are electrically connected in sequence.

[0030] The present invention further provides a plasma processing device comprising a vacuum reaction chamber, wherein the lower electrode assembly of the present invention is arranged in the vacuum reaction chamber.

[0031] The present invention also provides a method for preventing arc discharge in a lower electrode assembly, comprising:

[0032] Providing the lower electrode assembly of the present invention;

[0033] The conductive shielding layer is electrically connected to the central electrode to achieve no radio frequency voltage difference between the conductive shielding layer and the central electrode in the channel, thereby preventing arc discharge between the conductive shielding layer and the inner wall of the channel;

[0034] By arranging an insulating layer between the conductive core and the conductive shielding layer, and without a gap between the insulating layer and the conductive core and the conductive shielding layer, the conductive core and the conductive shielding layer are insulated in the radio frequency electric field, thereby preventing arc discharge between the conductive core and the conductive shielding layer.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1) The present invention is not affected by the number and power of the RF power sources connected to the lower electrode assembly, and can effectively prevent arc discharge from occurring in the channel accommodating the edge electrode feed assembly in the RF field space;

[0037] 2) The present invention avoids the loss of radio frequency energy due to arc discharge, effectively ensuring that the electric field strength in the vacuum reaction chamber meets the process requirements; the present invention ensures process stability and improves wafer yield;

[0038] 3) The present invention can effectively prevent components in the vacuum reaction chamber from being damaged by arc discharge;

[0039] 4) The edge electrode feeding assembly of the present invention can be a one-stage or segmented structure, and the edge electrode feeding assembly can pass through the central electrode or the components around the central electrode to feed the edge electrode; the edge electrode feeding assembly of the present invention is flexible in installation and is not restricted by the process in the reaction chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for the description. Obviously, the drawings described below are one embodiment of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort:

[0041] Figure 1 is a schematic diagram of a plasma processing device;

[0042] Figure 1A for Figure 1 Schematic diagram of arc discharge occurring at the dotted circle;

[0043] Figure 2A 、 Figure 2B Schematic diagram of the deflection phenomenon caused by focusing ring erosion;

[0044] Figure 3 、 Figure 3A 、 Figure 3B is a schematic diagram of the lower electrode assembly of the present invention;

[0045] Figure 3C for Figure 3 A partial enlarged schematic diagram;

[0046] Figure 4A 、 Figure 4B 、 Figure 4C A schematic diagram of controlling the plasma sheath and ion direction in the wafer edge region by the edge impedance adjustment unit of the present invention;

[0047] Figure 5 Schematic diagrams of various deformation structures of the edge electrode feeding assembly of the present invention;

[0048] Figure 6 Schematic diagram of the plasma processing device of the present invention. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] Figure 1 A plasma processing device is shown, which may be a capacitively coupled plasma processing device (CCP). The technical solution of the present invention may also be used for an inductively coupled plasma processing device. Figure 1The illustrated plasma processing apparatus 1 comprises a reaction chamber 10, which is substantially cylindrical and has substantially vertical sidewalls. An upper electrode 11 and a lower electrode 13 are disposed opposite each other within the reaction chamber 10. Typically, the upper electrode 11 can be a showerhead that supplies gas into the reaction chamber 10. The lower electrode 13 includes a base 131, upon which a wafer W to be processed is placed. The region between the upper and lower electrodes 11, 13 forms a processing zone, where high-frequency energy is generated to ignite and sustain the plasma. Reactive gas is supplied from a gas source 12 through the showerhead into the reaction chamber 10. One or more RF power sources 14 can be applied individually to the lower electrode 13 or simultaneously to both the upper and lower electrodes 11, 13, to deliver RF power to the lower electrode 13, or to both electrodes, thereby generating a large electric field within the reaction chamber 10. The majority of the electric field is contained within the processing region between the upper electrode 11 and the lower electrode 13. This electric field accelerates the small number of electrons present within the reaction chamber 10, causing them to collide with gas molecules of the incoming reactant gas. These collisions ionize the reactant gas and excite the plasma, thereby generating a plasma within the reaction chamber 10. When subjected to these strong electric fields, the neutral gas molecules in the reactant gas lose electrons, leaving behind positively charged ions. These positively charged ions are accelerated toward the lower electrode 13, where they combine with neutral species in the wafer being processed, stimulating wafer processing, such as etching and deposition.

[0051] Figure 1 The plasma processing device 1 further includes a confinement ring 105, which extinguishes the ignited plasma to prevent contamination of the inner wall of the reaction chamber and the exhaust pipe below the confinement ring.

[0052] An exhaust area is provided at a suitable position of the plasma processing device 1, and the exhaust area is connected to an external exhaust device (such as a vacuum pump 15) to extract the used reaction gas and by-product gas from the processing area during the processing process, and to establish an appropriate pressure in the processing area through gas flow.

[0053] A focus ring 104 is usually arranged around the base 131. Through the focus ring 104, the plasma is focused on the wafer area, making the plasma characteristics and ion directionality uniform at the center and edge of the wafer. However, as the plasma treatment process is repeated, such as Figure 2A 、 Figure 2BAs shown, ion bombardment causes increased erosion of the focus ring, reducing the thickness of the focus ring 104 and causing variations in the thickness of the plasma sheath at the wafer edge. The plasma sheath is non-uniform at the wafer edge, and the directionality of ions accelerated through the plasma sheath is also inconsistent. Consequently, the etched pattern at the wafer edge cannot be formed vertically, resulting in a titling phenomenon.

[0054] like Figure 1 As shown, to prevent deflection, an edge electrode 18 is typically provided around the base 131, allowing radio frequency (usually low frequency) power to be fed into the edge electrode 18 to adjust the edge electric field and ion directionality in the edge region. The edge electrode 18 may be a ring-shaped electrode surrounding the base 131 and insulated from the base 131.

[0055] like Figure 1 、 Figure 1A As shown, a channel can be provided inside the base 131, and the power of the RF power source 14 (usually low frequency) is fed into the edge electrode 18 through a conductive rod 19 provided in the channel. An insulating material 17 is usually provided on the inner wall of the channel (the insulating material 17 can cover the inner wall of the channel by splicing). The insulating material 17 prevents the RF signal connected to the base 131 from interfering with the RF signal connected to the edge electrode 18, thereby preventing the RF power supplied to the base 131 from being completely used to generate and maintain plasma, resulting in failure to meet the requirements of the wafer process and reducing the yield of the wafer W. Since there are mechanical errors when the conductive rod 19 is assembled in the channel, and the conductive rod 19 and the base itself have thermal expansion and contraction, a gap 16 needs to be provided between the conductive rod 19 and the insulating material 17 to facilitate installation while accommodating the thermal expansion and contraction of different components.

[0056] Furthermore, since a plurality of components with different thermal conductivity coefficients are provided on the periphery of the base, the temperature distribution of the base 131 is uneven, resulting in different sections of the channel accommodating the conductive rod 19 having different thermal expansion coefficients, and the gaps 16 between the conductive rod 19 and the sections of the insulating material 17 are different in size. In addition, the channel accommodating the conductive rod 19 usually has a bend, and at the bend connection, a larger gap 16 is more likely to be formed between the insulating material 17 and the conductive rod 19. Due to the gap 16, when a low-frequency, high-power RF power supply is fed to the edge electrode 18, the conductive rod 19 and the base 131 are equivalent to a capacitor in the RF field space, and thus there is an RF voltage difference between the conductive rod 19 and the base 131. When the RF voltage difference increases, as shown in FIG. Figure 1AAs shown, local discharge (light up) is easily generated in the gap 16, thereby damaging the insulating material 17. In severe cases, the edge electrode 18 and the base 131 may be short-circuited, causing arc discharge, which not only causes energy loss but also damages components in the reaction chamber.

[0057] To solve this problem, this embodiment provides a lower electrode assembly for preventing arc discharge, which is arranged in a vacuum reaction chamber, such as Figure 3 、 Figure 3A 、 Figure 3B As shown, the lower electrode assembly includes: a base 211, a facility plate 212, at least one RF power supply, a ring component, an edge electrode 28, and an edge electrode feeding assembly.

[0058] The base 211 is used to support the wafer, and the facility plate 212 is disposed at the bottom of the base. The center electrode 21 of the lower electrode assembly comprises the base 211 and the facility plate 212. A first RF power source of the at least one RF power source provides a first RF signal to the center electrode 21 via a corresponding first matching network 411. The ring component surrounds the center electrode 21. The edge electrode 28 is disposed within the ring component and is electrically insulated from the center electrode 21. A second RF signal is provided to the edge electrode 28 via an edge electrode feed assembly.

[0059] In an embodiment of the present invention, Figure 3 、 Figure 3A 、 Figure 3B As shown, the ring components include: a focus ring 24 , a cover ring 25 , a grounding ring 23 , and an insulating ring 26 .

[0060] The focusing ring 24 is arranged around the periphery of the wafer supported by the base 211 to control the RF electric field distribution at the edge of the wafer to be processed. The cover ring 25 is arranged around the periphery of the focusing ring to prevent the plasma in the vacuum reaction chamber from eroding the components below the cover ring. The grounding ring 23 is arranged around the periphery of the base and is located below the cover ring. An RF loop is formed between the plasma in the reaction chamber and the ground through the grounding ring 23. The insulating ring 26 is located below the focusing ring 24 and is arranged around between the base 211 and the grounding ring 23. In this embodiment, the edge electrode 28 is embedded in the insulating ring 26, insulated from the center electrode 21 by the insulating ring 26, and prevents discharge between the center electrode 21 and the grounding ring 23 by the insulating ring 26. In other embodiments, the edge electrode can be located inside the focusing ring or in the area between the focusing ring and the edge ring.

[0061] In one embodiment of the present invention, Figure 3As shown, the first RF power source is a low-frequency power source (e.g., a frequency below 2 MHz) used for ion acceleration or ion direction control. The edge electrode feed assembly is also connected to the first RF power source, and the first RF power source 410 provides a first RF signal to the center electrode 21 and a second RF signal to the edge electrode 28.

[0062] In another embodiment of the present invention, Figure 3A As shown, the center electrode 21 is connected to a first RF power supply 410 , and the edge electrode feeding assembly is connected to an independent second RF power supply 420 (usually a low-frequency power supply). The second RF power supply 420 provides a second RF signal to the edge electrode 28 through a corresponding second matching network 421 .

[0063] In another embodiment of the present invention, Figure 3B As shown, the at least one RF power supply further includes a third RF power supply 430 (a high frequency power supply, for example, a frequency of 13 MHz or more). The third RF power supply 430 is connected to the central electrode 21 through a corresponding third matching network 431, and plasma is generated in the reaction chamber by the power of the third RF power supply 430.

[0064] like Figure 3A 、 Figure 3B As shown, in one embodiment of the present invention, the edge impedance adjustment unit 440 is electrically connected between the second matching network 421 and the edge electrode feeding component. The edge electrode potential is adjusted by the edge impedance adjustment unit 440, causing the potential at the upper end of the focusing ring to change, thereby controlling the plasma sheath and ion directionality at the edge area of the wafer, and ensuring the uniformity of plasma processing in the edge area of the wafer.

[0065] The edge impedance control circuit in the embodiment of the present invention includes a variable capacitor. If the edge impedance adjustment unit 440 is controlled in the direction of reducing the impedance, the energy transmitted to the edge electrode 28 increases, and the potential at the upper end of the focus ring becomes higher. Figure 4A As shown, the plasma sheath is adjusted in the direction away from the focus ring 24 (as shown by the arrow in the figure). On the contrary, if the edge impedance adjustment unit 440 is controlled in the direction of increasing the impedance, the energy transmitted to the edge electrode 28 is reduced, and the potential at the upper end of the focus ring is reduced, as shown in FIG. Figure 4B As shown, the plasma sheath is adjusted toward the direction close to the focusing ring 24 (as shown by the arrow in the figure). Figure 4C As shown, the edge impedance adjustment unit 440 can control the plasma sheath in the edge area of the wafer to prevent the deflection phenomenon.

[0066] like Figure 3 、 Figure 3A 、 Figure 3BAs shown, the channel for accommodating the edge electrode feeding assembly passes through the center electrode 21. In another embodiment of the present invention, the channel may also pass through a component outside the center electrode 21, such as an insulating ring 26.

[0067] like Figure 3 、 Figure 3A 、 Figure 3B 、 Figure 3C As shown, the edge electrode feeding assembly includes: a conductive core 226 , a conductive shielding layer 229 disposed around the conductive core, an insulating layer 227 filled between the conductive core 226 and the conductive shielding layer 229 , and a plurality of conductive connectors 222 .

[0068] There is no gap between the insulating layer 227 and the conductive core 226 and the conductive shielding layer 229. A gap 30 is provided between the conductive shielding layer 229 and the inner wall 31 of the channel to accommodate the thermal expansion and contraction of the edge electrode feeding assembly and the channel, as well as the mechanical error of the edge electrode feeding assembly in the channel. Figure 3 、 Figure 3A 、 Figure 3B 、 Figure 3C As shown, the conductive shielding layer 229 is electrically connected to the channel inner wall 31 through the connecting member 222 .

[0069] It is known that arc discharge between two conductive components in a radio frequency field environment must meet two conditions:

[0070] 1) There is a voltage difference between the two conductive elements;

[0071] 2) There is a space (ie, gap 30 ) between the two conductive elements.

[0072] In the present invention, the insulating layer 227 eliminates the space between the conductive core 226 and the conductive shielding layer 229, preventing the conductive core 226 and the conductive shielding layer 229 from generating an RF voltage difference in the RF field space (there is a voltage difference, but no space), thereby avoiding arc discharge between the conductive core 226 and the conductive shielding layer 229. Furthermore, the present invention electrically connects the conductive shielding layer 229 to the channel inner wall 31, eliminating the voltage difference between the conductive shielding layer 229 and the channel inner wall 31. Although there is space between the conductive shielding layer 229 and the channel inner wall 31, arc discharge does not occur in this space (there is space, but no voltage difference). Through the present invention, the space between the conductive thin rod 19 and the insulating material 17 in the prior art is transferred outward to the space between the conductive shielding layer 229 and the channel inner wall 31, where there is no voltage difference, effectively preventing arc discharge from occurring in the lower electrode assembly.

[0073] In an embodiment of the present invention, the conductive core 226 can be a flexible conductive wire or a rigid conductive rod; the conductive shielding layer 229 can be formed by coating the outer surface with Al2O3; the insulating layer 227 can be made of any of Teflon, glass, and ceramic; and the connector 222 can be at least one of a bolt, a spring, and a conductive gasket. The connector 222 can be made of at least one of aluminum, gold, silver, copper, and titanium.

[0074] like Figure 5 As shown, in one embodiment of the present invention, the edge electrode feeding assembly is a one-stage structure ( Figure 5 In another embodiment of the present invention, the edge electrode feeding assembly can also be a segmented structure ( Figure 5 ); the segments of the segmented edge electrode feed assembly are electrically connected in sequence.

[0075] The present invention also provides a plasma processing device, such as Figure 6 As shown, it includes a vacuum reaction chamber, in which the lower electrode assembly of the present invention is arranged. Figure 6 The plasma processing device 2 further includes a confinement ring 205, which is arranged between the periphery of the grounding ring and the side wall of the reaction chamber. The confinement ring 205 extinguishes the ignited plasma to prevent contamination of the inner wall of the reaction chamber and the exhaust pipe below the confinement ring.

[0076] The present invention also provides a method for preventing arc discharge in a lower electrode assembly, comprising:

[0077] Providing the lower electrode assembly of the present invention;

[0078] The conductive shielding layer 229 is electrically connected to the central electrode 21 to achieve no radio frequency voltage difference between the conductive shielding layer 229 and the central electrode 21 in the channel, thereby preventing arc discharge between the conductive shielding layer 229 and the inner wall 31 of the channel;

[0079] By setting an insulating layer 227 between the conductive core 226 and the conductive shielding layer 229, and without a gap between the insulating layer 227 and the conductive core 226 and the conductive shielding layer 229, the conductive core 226 and the conductive shielding layer 229 are insulated in the radio frequency electric field, thereby preventing arc discharge between the conductive core 226 and the conductive shielding layer 229.

[0080] The lower electrode assembly of the present invention is not affected by the number of connected RF power sources or the RF power, and can effectively prevent arc discharge from occurring in the channel accommodating the edge electrode feeding assembly in the RF field space. Since the present invention avoids the loss of RF energy due to arc discharge, it effectively ensures that the electric field strength in the vacuum reaction chamber meets the process requirements, ensures the stability of the process and improves the wafer yield, and can effectively prevent the components in the vacuum reaction chamber from being damaged by arc discharge. The edge electrode feeding assembly of the present invention can be a one-stage or segmented structure, and the edge electrode feeding assembly can pass through the center electrode 21 or the components on the periphery of the center electrode 21 to feed the edge electrode 28, so the edge electrode feeding assembly can be installed flexibly and is not restricted by the process in the reaction chamber.

[0081] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A lower electrode assembly for preventing arc discharge, arranged in a vacuum reaction chamber, characterized in that: Include: a base, for supporting the wafer and serving as a central electrode of the lower electrode assembly; a radio frequency power supply, configured to provide a first radio frequency signal to the central electrode; a ring member surrounding the central electrode; an edge electrode surrounding the central electrode and electrically insulated from the central electrode; an edge electrode feeding assembly, configured to provide a second radio frequency signal to the edge electrode; The edge electrode feeding assembly comprises: a conductive core and a conductive shielding layer arranged around the outer periphery of the conductive core, an insulating layer is filled between the conductive core and the conductive shielding layer, and the conductive shielding layer is electrically connected to the central electrode; There is a gap between the conductive shielding layer and the inner wall of the channel accommodating the edge electrode feeding assembly.

2. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: The gap is used to accommodate thermal expansion and contraction of the channel or size mismatch caused by mechanical errors resulting from a combination of surrounding components.

3. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: There is no gap between the insulating layer and the conductive core and the conductive shielding layer.

4. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: The edge electrode feeding assembly further comprises: a plurality of conductive connecting members, which are arranged in the channel and electrically connect the conductive shielding layer and the central electrode.

5. The lower electrode assembly for preventing arc discharge according to claim 4, wherein: The connecting member is at least one of a bolt, a spring, and a conductive gasket.

6. The lower electrode assembly for preventing arc discharge according to claim 4, wherein: The material of the connecting piece includes at least one of aluminum, gold, silver, copper and titanium.

7. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: It also includes a facility plate, which is arranged at the bottom of the base, and the center electrode includes the facility plate and the base.

8. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: The conductive core is a flexible conductive wire or a hard conductive rod.

9. The lower electrode assembly for preventing arc discharge according to claim 8, wherein: The edge electrode feeding assembly is electrically connected to a corresponding radio frequency power supply via an edge impedance adjustment unit; and the edge electrode potential is adjusted via the edge impedance adjustment unit.

10. The lower electrode assembly for preventing arc discharge according to claim 3, wherein: The insulating layer is made of any one of Teflon, glass, and ceramic.

11. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: The outer surface of the conductive shielding layer contains Al2O3 formed by plating.

12. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: The ring component includes a focusing ring, which is arranged around the outer periphery of the base and controls the distribution of the radio frequency electric field at the edge of the wafer to be processed.

13. The lower electrode assembly for preventing arc discharge according to claim 12, wherein: The ring component further comprises a cover ring which is arranged around the outer periphery of the focusing ring to prevent the plasma in the vacuum reaction chamber from corroding various components below the cover ring.

14. The lower electrode assembly for preventing arc discharge according to claim 13, wherein: The ring component further comprises: a grounding ring which is arranged around the outer periphery of the base and is located below the cover ring; a radio frequency loop is formed between the plasma in the reaction chamber and the ground through the grounding ring.

15. The lower electrode assembly for preventing arc discharge according to claim 14, wherein: The ring component further includes: an insulating ring located below the focusing ring; an edge electrode embedded in the insulating ring, or located between the insulating ring and the focusing ring; and the insulating ring prevents discharge between the center electrode and the grounding ring.

16. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: The second radio frequency signal is connected to the radio frequency power source of the first radio frequency signal or to an independent radio frequency power source.

17. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: A passageway housing the edge electrode feed assembly passes through the center electrode and / or components outside the center electrode.

18. The lower electrode assembly for preventing arc discharge according to claim 1, wherein: The edge electrode feeding assembly is a one-stage or segmented edge electrode feeding assembly; the segments of the segmented edge electrode feeding assembly are electrically connected in sequence.

19. A plasma processing device comprising a vacuum reaction chamber, characterized in that: The vacuum reaction chamber is provided with a lower electrode assembly as described in any one of claims 1 to 18.

20. A method for preventing arc discharge in a lower electrode assembly, characterized in that: Include: Providing a lower electrode assembly according to any one of claims 1 to 18; The conductive shielding layer is electrically connected to the central electrode to achieve no radio frequency voltage difference between the conductive shielding layer and the central electrode in the channel, thereby preventing arc discharge between the conductive shielding layer and the inner wall of the channel; By arranging an insulating layer between the conductive core and the conductive shielding layer, and without a gap between the insulating layer and the conductive core and the conductive shielding layer, the conductive core and the conductive shielding layer are insulated in the radio frequency electric field, thereby preventing arc discharge between the conductive core and the conductive shielding layer.

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