Lower electrode assembly and plasma processing device

Abstract

The utility model provides a lower electrode assembly and a plasma processing device, the lower electrode assembly is arranged in a vacuum reaction chamber, and the lower electrode assembly comprises a pedestal used for supporting a wafer, the pedestal is electrically connected with a radio frequency power supply; the facility plate is arranged at the bottom of the base; the upper isolating ring is arranged on the periphery of the base and the facility plate in a surrounding manner; the lower isolating ring is arranged below the facility plate and the upper isolating ring and bears the facility plate; a first fastener which is electrically grounded is arranged in the lower isolating ring; and the first elastic insulating ring is at least partially arranged between the facility plate and the upper isolating ring in a surrounding manner and is in elastic contact with the outer side wall of the facility plate and the top of the lower isolating ring. According to the utility model, the risk that the lower electrode assembly is broken down due to arc discharge is greatly reduced, and the safety of wafer processing is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor equipment, in particular to a lower electrode assembly and a plasma processing device. Background Art

[0002] In the field of semiconductor manufacturing technology, it is often necessary to perform plasma treatment on a wafer to be processed in a plasma processing device. The plasma processing device has a vacuum reaction chamber, in which a susceptor and a facility plate are arranged. The facility plate is arranged below the susceptor, and the susceptor is used to carry the wafer and serve as the lower electrode of the reaction chamber.

[0003] There are multiple components around the base and facility plate, which are used to control the RF electric field distribution at the edge of the wafer, form an RF loop between the plasma in the reaction chamber and the ground, etc. There is a thermal deformation accommodation gap between the base, facility plate and surrounding components, and the gap still exists even at the process temperature. In some processes (such as high aspect ratio etching processes), it is necessary to feed a higher RF power to the lower electrode, so that there is a large voltage difference between the lower electrode and the surrounding components. Therefore, arc discharge is likely to occur in the above gap, which will damage the components in the reaction chamber and affect the safety of wafer processing. Utility Model Content

[0004] The utility model aims to provide a lower electrode assembly and a plasma processing device, so as to reduce the risk of the lower electrode assembly being broken down due to arc discharge, and ensure the safety of wafer processing.

[0005] In order to achieve the above object, the utility model provides a lower electrode assembly, which is arranged in a vacuum reaction chamber and includes:

[0006] A base, used to support the wafer, the base being electrically connected to a radio frequency power source;

[0007] A facility plate, arranged at the bottom of the base;

[0008] an upper isolation ring disposed around the periphery of the base and the facility plate;

[0009] A lower isolating ring is disposed below the facility plate and the upper isolating ring and supports the facility plate; the interior of the lower isolating ring has a first fastener electrically grounded;

[0010] A first elastic insulating ring is at least partially disposed around the facility plate and the upper isolation ring and elastically contacts the outer side wall of the facility plate and the top of the lower isolation ring.

[0011] Optionally, the lower electrode assembly also includes a lower grounding ring; the lower grounding ring is arranged along the radial direction of the base and supports the lower isolation ring; the lower isolation ring and the lower grounding ring are connected by the first fastener.

[0012] Optionally, the top surface of the lower isolation ring is provided with an annular groove corresponding to the position of the upper isolation ring; the lower part of the first elastic insulating ring is located in the annular groove and elastically contacts the side wall of the annular groove; and the first fastener passes through the bottom wall of the annular groove.

[0013] Optionally, the lower portion of the upper isolation ring is located in the annular groove.

[0014] Optionally, when the temperature in the reaction chamber is lower than the process temperature, a thermal deformation accommodating gap is provided between the inner side wall of the upper isolation ring and the first elastic insulating ring.

[0015] Optionally, an inner side wall of the upper isolation ring is provided with a mounting groove for accommodating the first elastic insulating ring.

[0016] Optionally, a top surface of the first elastic insulating ring is lower than a top surface of the upper isolation ring.

[0017] Optionally, the facility plate has a plurality of transverse channels and a plurality of first longitudinal channels inside, and each of the transverse channels is respectively connected to one of the first longitudinal channels; the base has a plurality of second longitudinal channels inside, and each of the second longitudinal channels is respectively connected to one of the first longitudinal channels; the transverse channels and the corresponding first longitudinal channels and second longitudinal channels form an electrical channel for supplying power to electrical components around the base.

[0018] Optionally, the transverse channel includes a first mounting opening formed on an outer side wall of the facility plate; and the first elastic insulating ring covers the first mounting opening.

[0019] Optionally, the first longitudinal channel includes a second mounting opening formed on the bottom surface of the facility plate; the lower electrode assembly further includes a second elastic insulating ring; the second elastic insulating ring is disposed between the facility plate and the lower isolation ring and covers the second mounting opening.

[0020] Optionally, the electrical element is an edge electrode, and the electrical channel contains a first conductive core for providing a radio frequency signal to the edge electrode.

[0021] Optionally, the electrical element is a heating element, and the electrical channel contains a second conductive core for supplying power to the heating element.

[0022] Optionally, an insulating material is filled between the first conductive core and the inner wall of the electrical channel, and between the second conductive core and the inner wall of the electrical channel.

[0023] Optionally, the base includes a base body and a boss formed on the top of the base body; the lower electrode assembly also includes a focusing ring arranged around the outer periphery of the boss, for controlling the RF electric field distribution at the edge of the wafer to be processed; the second longitudinal channel is located below the focusing ring; the edge electrode and the heating element are arranged inside the focusing ring, or between the focusing ring and the base body.

[0024] Optionally, a plurality of third longitudinal channels are provided inside the facility plate; a plurality of fourth longitudinal channels are provided inside the base, and each of the fourth longitudinal channels is connected to a third longitudinal channel respectively; the third longitudinal channels and the corresponding fourth longitudinal channels form an installation channel for a second fastener, and the second fastener is used to fix the base and the facility plate; the third longitudinal channel includes a third installation port formed on the bottom surface of the facility plate; and the second elastic insulating ring covers the third installation port.

[0025] Optionally, the lower electrode assembly further includes a middle grounding ring, which surrounds the outer circumference of the upper isolation ring and the lower isolation ring; the middle grounding ring is connected to the top of the lower grounding ring and is arranged along the axial direction of the base.

[0026] Optionally, the lower electrode assembly further includes a cover ring; the cover ring is disposed around the outer circumference of the focusing ring and is located above the upper isolation ring and the middle grounding ring to prevent the plasma in the reaction chamber from corroding components below the cover ring.

[0027] Optionally, the first elastic insulating ring and the second elastic insulating ring are made of perfluororubber.

[0028] Optionally, the outer side walls of the base and the facility plate are provided with a protective layer resistant to plasma corrosion.

[0029] The utility model also provides a plasma processing device, which comprises a vacuum reaction chamber, wherein the lower electrode assembly as described in the utility model is arranged in the vacuum reaction chamber.

[0030] Compared with the prior art, the technical solution of the utility model has at least the following beneficial effects:

[0031] 1) In the lower electrode assembly and plasma processing device of the utility model, at least a portion of the first elastic insulating ring elastically contacts the outer wall of the facility plate and the top of the lower isolation ring, thereby effectively blocking the discharge path between the facility plate and the first fastener in the lower isolation ring, effectively avoiding arc discharge in the gap between the facility plate and its surrounding components in a high-power radio frequency field, greatly reducing the risk of components in the vacuum reaction chamber being broken down, and ensuring the safety of wafer processing.

[0032] 2) The utility model avoids the loss of radio frequency energy applied to the lower electrode due to arc discharge, effectively ensures that the electric field intensity in the vacuum reaction chamber meets the process requirements, ensures the stability of the process and improves the wafer yield.

[0033] 3) In the present invention, the gap width between the facility plate and its surrounding components has no effect on the breakdown voltage threshold of the lower electrode assembly, thereby greatly reducing the dimensional accuracy requirements for the components of the lower electrode assembly.

[0034] 4) In the present invention, the annular groove on the top surface of the lower isolation ring extends the discharge path between the facility plate and the first fastener. Even in the case of elastic failure of the first elastic insulating ring, the annular groove can reduce the possibility of arc discharge between the facility plate and the first fastener.

[0035] 5) The electrical channel in the utility model greatly facilitates the installation of the first conductive core and the second conductive core. The first installation opening and the second installation opening of the electrical channel are respectively blocked by the first elastic insulating ring and the second elastic insulating ring, which greatly reduces the risk of tip discharge at the first installation opening and the second installation opening.

[0036] 6) The installation channel of the second fastener (used to fix the connection between the base and the facility plate) has a third installation port at the bottom of the facility plate. The second elastic insulating ring of the utility model can also block the third installation port, greatly reducing the risk of tip discharge at the third installation port.

[0037] 7) The first elastic insulating ring and the second elastic insulating ring of the utility model are both made of plasma corrosion resistant materials, can be used repeatedly and for a long time, have low economic cost, and are easy to replace, thereby improving the efficiency of wafer processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solution of the utility model, the following is a brief introduction to the drawings required for the description. Obviously, the drawings described below are an embodiment of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work:

[0039] Figure 1is a schematic diagram of a plasma processing device;

[0040] Figure 2 A schematic diagram of a lower electrode assembly in an embodiment of the present utility model;

[0041] Figure 3 This is a schematic diagram of another embodiment of the utility model, in which an annular groove is formed on the top surface of the lower isolation ring;

[0042] Figure 4 This is a schematic diagram of supplying power to edge electrodes through electrical channels penetrating a base and a facility board in one embodiment of the utility model;

[0043] Figure 5 This is a schematic diagram of supplying power to a heating element through an electrical passage penetrating a base and a facility plate in another embodiment of the present utility model;

[0044] Figure 6 This is a schematic diagram of another embodiment of the present invention, in which the second elastic insulating ring covers the third mounting opening;

[0045] Figure 7 A schematic diagram of a plasma processing device of the present invention;

[0046] Figure 8 It is a schematic diagram of a plasma processing device of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0048] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0049] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0050] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0051] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0052] In addition, in the description of the present application, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0053] Figure 1 A plasma processing device 1 is shown, Figure 1 The plasma processing device 1 shown has a reaction chamber 10 , which is substantially cylindrical, and has a substantially vertical side wall 101 . The reaction chamber 10 has an upper electrode and a lower electrode that are oppositely arranged.

[0054] Figure 1 In the figure, the upper electrode is a nozzle 110 for supplying gas into the reaction chamber 10, and the lower electrode is a base 120 (conductive material). The wafer W to be processed is placed above the base 120. The area between the upper electrode and the lower electrode is a processing area, which will form high-frequency energy to ignite and maintain plasma. The reaction gas is input into the reaction chamber 10 from the gas source 111 through the nozzle 110, and one or more radio frequency power supplies 140 can be applied to the lower electrode alone or to the upper electrode and the lower electrode at the same time, so as to generate a large electric field inside the reaction chamber 10. Most of the electric field is contained in the processing area between the upper electrode and the lower electrode. This electric field accelerates a small amount of electrons present in the reaction chamber 10, causing them to collide with the gas molecules of the input reaction gas. These collisions lead to ionization of the reaction gas and excitation of the plasma, thereby generating plasma in the reaction chamber 10. The neutral gas molecules of the reaction gas lose electrons when subjected to these strong electric fields, leaving positively charged ions. The positively charged ions are accelerated toward the lower electrode, combined with neutral substances in the processed wafer W, and stimulate wafer processing, i.e., etching, deposition, etc.

[0055] 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 150) to extract the spent reaction gas and by-product gas from the processing area during the processing, and to establish an appropriate pressure in the processing area through gas flow.

[0056] like Figure 1 As shown, the facility plate 160 (conductive material) is arranged at the bottom of the base 120. A plurality of components (some of which are conductive components) are arranged around the base 120 and the facility plate 160. There is a thermal deformation accommodation gap between the base 120, the facility plate 160 and the surrounding components. Under the process temperature, the thermal deformation accommodation gap usually does not completely disappear. On the other hand, due to the existence of machining tolerances of various components, there is inevitably a machining gap between the base 120, the facility plate 160 and the surrounding components. In summary, the gap between the base 120, the facility plate 160 and the surrounding components cannot always be completely avoided.

[0057] In some processes (such as high aspect ratio etching processes), it is necessary to feed a higher RF power to the lower electrode, so that there is a larger voltage difference between the base 120, the facility plate 160 and the surrounding conductive components, so that arc discharge (such as Figure 1 According to the Paschen curve, the larger the gap width, the lower the breakdown voltage threshold between the base 120, the facility board 160 and the surrounding conductive components, so it is easier for the base 120, the facility board 160, etc. to be broken down, which greatly affects the safety of wafer processing.

[0058] The utility model provides a lower electrode assembly and a plasma processing device, which blocks the discharge path between the radio frequency power radiation area and the grounding area by elastically contacting the outer side wall of the facility plate and the top of the lower isolation ring through at least a portion of a first elastic insulating ring, greatly reducing the risk of the lower electrode assembly being broken down due to arc discharge, improving the robustness of the lower electrode assembly, and ensuring the safety of wafer processing.

[0059] According to one aspect of the present invention, a lower electrode assembly is provided, such as Figure 2 As shown, it is arranged in a vacuum reaction chamber, and the lower electrode assembly includes: a base 220, an upper isolation ring 231, a lower isolation ring 232, a focusing ring 240, a first elastic insulating ring 251, a facility plate 260, a cover ring 270, a middle grounding ring 281, and a lower grounding ring 282.

[0060] like Figure 2As shown, the base 220 is used to support the wafer W, and the facility plate 260 is arranged at the bottom of the base 220. The base 220 and the facility plate 260 can be made of aluminum or other conductive materials. In some embodiments, the outer surfaces of the base 220 and the facility plate 260 are also coated with a coating of aluminum oxide or yttrium oxide material to increase the breakdown voltage of the base 220 and the facility plate 260.

[0061] The base 220 serves as the lower electrode of the reaction chamber, and at least one radio frequency power source is applied to the lower electrode. Figure 2 As shown, the base 220 is electrically connected to a first RF power source 221 (a high frequency power source, for example, a frequency of 13 MHz or more) and a second RF power source 222 (a low frequency power source, for example, a frequency of 2 MHz or less). The RF power of the first RF power source 221 is used to generate a high density plasma in the reaction chamber. The RF power of the second RF power source 222 is used to accelerate ions, thereby bombarding the wafer.

[0062] like Figure 2 As shown, the base 220 includes a base body 221 and a boss 222 formed on the top of the base body 221. A focusing ring 240 (which may be made of silicon carbide) is arranged around the periphery of the boss 222 to control the RF electric field distribution and sheath thickness at the edge of the wafer to be processed, so as to achieve a more uniform plasma etching effect.

[0063] like Figure 2 As shown, the cover ring 270 is disposed around the outer circumference of the focus ring 240 to prevent the plasma in the vacuum reaction chamber from eroding the components below the cover ring 270 .

[0064] like Figure 2 As shown, the upper isolation ring 231 is disposed around the outer periphery of the base 220 and the facility plate 260. The lower isolation ring 232 is disposed below the facility plate 260 and the upper isolation ring 231, and the lower isolation ring 232 also supports the facility plate 260. The upper isolation ring 231 and the lower isolation ring 232 are both made of insulating materials, such as quartz, alumina, etc.

[0065] like Figure 2As shown, the middle grounding ring 281 and the lower grounding ring 282 are located below the cover ring 270. The middle grounding ring 281 is arranged along the axial direction of the base 220 and surrounds the outer periphery of the upper isolation ring 231 and the lower isolation ring 232. The lower grounding ring 282 is connected to the bottom of the middle grounding ring 281 and is arranged along the radial direction of the base 220. A radio frequency loop between the plasma in the reaction chamber and the ground is formed by the middle grounding ring 281 and the lower grounding ring 282. In this embodiment, the lower grounding ring 282 provides support for the lower isolation ring 232 and the upper isolation ring 231. In another embodiment, the lower grounding ring 282 supports the lower isolation ring 232, and the upper isolation ring 231 is hung on the cover ring 270. The upper isolation ring 231 and the lower isolation ring 232 are used to achieve isolation between the radio frequency power radiation area (RF hot, including the base 220 and the facility plate 260) and the grounding area (including the middle grounding ring 281 and the lower grounding ring 282), thereby reducing the radio frequency power loss fed to the lower electrode.

[0066] Usually, there is a labyrinth structure on the top of the upper isolation ring 231 (this is the prior art and will not be described in detail here). The labyrinth structure greatly extends the discharge path between the base 220 and the top of the middle ground ring. Even if a higher RF power is fed to the lower electrode, Figure 2 Arc discharge is usually less likely to occur within the range shown by the middle dotted circle.

[0067] like Figure 2 As shown, the lower isolation ring 232 has a first fastener 233 (such as a screw) inside, which is used to connect the lower isolation ring 232 and the lower grounding ring 282. Obviously, the first fastener 233 is the grounding point closest to the facility plate 260. When a higher RF power is fed to the lower electrode, arc discharge is more likely to occur between the facility plate 260 and the first fastener 233.

[0068] like Figure 2 As shown, in this embodiment, the first elastic insulating ring 251 is sleeved on the periphery of the base 220 and the facility plate 260. And a mounting groove is opened on the inner side wall of the upper isolation ring 231 (facing the base 220 and the facility plate 260) to accommodate the first elastic insulating ring 251. Since the top of the upper isolation ring 231 has a higher temperature during the process, the top surface of the first elastic insulating ring 251 is lower than the top surface of the upper isolation ring 231 to prevent the first elastic insulating ring 251 from overheating and losing its elasticity.

[0069] like Figure 2 As shown, the lower portion of the first elastic insulating ring 251 is disposed around the facility plate 260 and the upper isolating ring 231, and is always elastically in contact with the outer side wall of the facility plate 260 and the top surface of the lower isolating ring 232. A gap is provided between the first elastic insulating ring 251 and the side wall of the mounting groove to accommodate thermal deformation of the facility plate 260 and the base 220, while also facilitating the installation of the upper isolating ring 231.

[0070] The discharge path L1 (such as the discharge path L2 between the base 220, the facility plate 260 and the first fastener 233) is blocked by the first elastic insulating ring 251. Figure 2 As shown in the figure, when a high RF power is fed to the lower electrode, arc discharge can be effectively avoided in the gap between the facility plate 260 and the upper isolation ring 231, and in the gap between the upper isolation ring 231 and the lower isolation ring 232, thereby preventing component damage and greatly ensuring the safety of wafer processing. It is easy to understand that the first elastic insulating ring 251 also effectively blocks the base 220 and the facility plate 260 from discharging along the above-mentioned discharge path L1 to the middle grounding ring 281 and the lower grounding ring 282, further improving the safety of the lower electrode assembly.

[0071] The utility model greatly reduces the radio frequency energy lost due to arc discharge, effectively ensures that the electric field intensity in the reaction chamber meets the process requirements, ensures the stability of the process and improves the wafer yield.

[0072] Since the first elastic insulating ring 251 blocks the discharge path L1, the width of the gap between the base 220, the facility plate 260 and the surrounding components no longer affects the breakdown voltage threshold between the RF power radiation area and the grounding area, thereby greatly reducing the dimensional accuracy requirements for each component of the lower electrode assembly.

[0073] In this embodiment, the material of the first elastic insulating ring 251 is perfluororubber, which has strong plasma corrosion resistance and high voltage resistance, can be used multiple times and for a long time, and has low economic cost. In addition, the first elastic insulating ring 251 is easy to replace, which helps to improve the efficiency of wafer processing.

[0074] like Figure 3 As shown, in another embodiment, the top surface of the lower isolation ring 232 is provided with an annular groove corresponding to the position of the upper isolation ring 231. The lower portion of the first elastic insulating ring 251 is located in the annular groove and elastically contacts the side wall 2321 of the annular groove. The lower portion of the upper isolation ring 231 is also located in the annular groove, and the first fastener 233 passes through the bottom wall 2322 of the annular groove. Compared with the above-mentioned discharge path L1, the annular groove makes the discharge path L2 between the base 220, the facility plate 260 and the first fastener 233 longer, thereby increasing the breakdown voltage threshold between the facility plate 260 and the first fastener 233. Even in the case of elastic failure of the first elastic insulating ring 251, the annular groove can reduce the possibility of arc discharge between the facility plate 260 and the first fastener 233.

[0075] In another embodiment, a plurality of electrical channels are provided through the base 220 and the facility plate 260 to supply power to electrical components around the base 220. Figure 4As shown, the facility plate 260 has a plurality of transverse channels 2601 (arranged along the radial direction of the facility plate 260 in this embodiment) and a plurality of first longitudinal channels 2602, each of which is connected to a first longitudinal channel 2602. The base 220 has a plurality of second longitudinal channels 2202 (located below the focus ring 240) disposed inside, each of which is connected to a first longitudinal channel 2602. The transverse channel 2601 and the corresponding first longitudinal channel 2602 and second longitudinal channel 2202 form an electrical channel.

[0076] like Figure 4 As shown, in one embodiment of the present invention, the electrical element may be an edge electrode 2911 , and the electrical channel contains a first conductive core 2912 for providing a radio frequency signal to the edge electrode 2911 . Figure 4 The edge electrode 2911 is disposed inside the focus ring 240. In other embodiments, the edge electrode 2911 may also be disposed between the focus ring 240 and the base body 221. The edge electrode 2911 is usually electrically connected to a low-frequency RF power source to adjust the electric field and ion directivity of the wafer edge to avoid uneven etching at different phase angles of the wafer.

[0077] The first conductive core 2912 and the base 220, and the first conductive core 2912 and the facility board 260 are equivalent to a capacitor in the radio frequency electric field. In the present invention, an insulating material is filled between the first conductive core 2912 and the inner wall of the electrical channel to prevent arc discharge in the electrical channel where the first conductive core 2912 is located due to the voltage difference between the first conductive core 2912 and the base 220 and the facility board 260.

[0078] The temperature of the focus ring 240 may also affect the deposition of polymer at the edge of the wafer, resulting in microscopic critical dimension differences. Figure 5 As shown, the electrical element is a heating element 2913 for adjusting the temperature of the focusing ring 240 , and the electrical channel contains a second conductive core 2914 for supplying power to the heating element 2913 . Figure 5 The heating element 2913 is disposed between the focus ring 240 and the base body 221. In other embodiments, the heating element 2913 may also be disposed inside the focus ring 240. An insulating material is also filled between the second conductive core 2914 and the inner wall of the electrical channel to prevent arc discharge from occurring in the electrical channel where the second conductive core 2914 is located.

[0079] like Figure 4 , Figure 5As shown, the transverse channel 2601 includes a first installation opening 2601a formed on the outer side wall of the facility plate, and the first longitudinal channel 2602 includes a second installation opening 2602a formed on the bottom surface of the facility plate. In this embodiment, the first conductive core 2912 and the second conductive core 2914 are segmented structures, and the segments of the segmented structures are connected in sequence. Since the segments of the first conductive core 2912 and the second conductive core 2914 can extend from the first installation opening 2601a and the second installation opening 2602a into the interior of the facility plate 260 and the base 220, the electrical channel in the utility model greatly facilitates the installation of the first conductive core 2912 and the second conductive core 2914. In other embodiments, it can also be a one-segment structure, which is not limited in the utility model.

[0080] like Figure 4 , Figure 5 As shown, the first installation opening 2601a has a pointed structure because the inner wall of the transverse channel 2601 is perpendicular to the outer wall of the facility plate 260. In the present invention, the first elastic insulating ring 251 covers the first installation opening 2601a, and the risk of pointed discharge around the first installation opening 2601a is greatly reduced by the first elastic insulating ring 251.

[0081] like Figure 4 , Figure 5 As shown, since the inner wall of the first longitudinal channel 2602 is perpendicular to the bottom surface of the facility plate 260, the second installation opening 2602a also has a pointed structure. The lower electrode assembly of the utility model further includes a second elastic insulating ring 252, which is arranged between the facility plate 260 and the lower isolation ring 232 and covers the second installation opening 2602a. The risk of tip discharge around the second installation opening 2602a is greatly reduced by the second elastic insulating ring 252. The second elastic insulating ring 252 is made of the same material as the first elastic insulating ring 251.

[0082] like Figure 6 The facility plate 260 is provided with a plurality of third vertical channels 2603 inside, and the base 220 is provided with a plurality of fourth vertical channels 2204 inside, and each fourth longitudinal channel 2204 is connected to a third longitudinal channel 2603. The third longitudinal channel 2303 and the corresponding fourth longitudinal channel 2204 form a second fastener ( Figure 6 The second fastener is used to fix the base 220 and the facility plate 260.

[0083] like Figure 6As shown, the third longitudinal channel 2603 includes a third installation opening 2603a formed on the bottom surface of the facility plate 260. The inner wall of the third longitudinal channel 2603 is perpendicular to the bottom surface of the facility plate 260, and the third installation opening 2603a also has a tip structure around it. The third longitudinal channel 2603 and the first longitudinal channel 2601 are at the same distance from the central axis of the facility plate. Figure 6 As shown, the second elastic insulating ring 252 can also cover the third installation opening 2603a, greatly reducing the risk of tip discharge around the third installation opening 2603a.

[0084] In this embodiment, the horizontal distances between the first longitudinal channel 2602 and the third longitudinal channel 2603 and the central axis of the base are the same, so the second installation opening 2602a and the third installation opening 2603a can be covered simultaneously by one second elastic insulating ring 252. In other embodiments, the horizontal distances between the first longitudinal channel 2601 and the third longitudinal channel 2603 and the central axis of the base are different, and two second elastic insulating rings 252 are required to cover the first longitudinal channel 2601 and the third longitudinal channel 2603 respectively.

[0085] In this embodiment, there are a second fastener, an edge electrode 2911 and a heating element 2913, and from a top view, the second fastener, the edge electrode 2911 and the heating element 2913 are located on the same ring. In other embodiments, the second fastener, the edge electrode and the heating element may not be located on the same ring.

[0086] like Figure 7 As shown, the utility model further provides a plasma processing device 2, which is a capacitively coupled plasma processing device. The plasma processing device 2 comprises a vacuum reaction chamber 20, in which a lower electrode assembly as described in the utility model is arranged.

[0087] like Figure 8 As shown, the technical solution of the utility model can also be used in an inductively coupled plasma (ICP) processing device. Figure 8 The plasma processing device 3 includes: a vacuum reaction chamber 30, a liner 320, an insulating window 317, and a plurality of inductively coupled coils 315.

[0088] The lower electrode assembly as described in the present utility model is arranged in the vacuum reaction chamber 30. The vacuum reaction chamber 30 comprises a reaction chamber side wall 301 which is made of metal material and is roughly cylindrical. The liner 320 is arranged inside the reaction chamber to protect the inner wall of the reaction chamber 30 from being corroded by plasma. An insulating window 317 is arranged at the top of the reaction chamber 30. A reaction gas injection port 303 is arranged at one end of the reaction chamber side wall 301 close to the insulating window 317. An inductive coupling coil 315 is arranged above the insulating window 317. The inductive coupling coil 315 generates an induced magnetic field under the excitation of the radio frequency power supply 316. The reaction gas in the reaction chamber 30 generates plasma under the action of the induced magnetic field.

[0089] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A lower electrode assembly, arranged in a vacuum reaction chamber, characterized in that: Include: A base, used to support the wafer, the base being electrically connected to a radio frequency power source; A facility plate, arranged at the bottom of the base; an upper isolation ring disposed around the periphery of the base and the facility plate; A lower isolating ring is disposed below the facility plate and the upper isolating ring and supports the facility plate; the interior of the lower isolating ring has a first fastener electrically grounded; A first elastic insulating ring is at least partially disposed around the facility plate and the upper isolation ring and elastically contacts the outer side wall of the facility plate and the top of the lower isolation ring.

2. The lower electrode assembly according to claim 1, characterized in that It also includes a lower grounding ring; the lower grounding ring is arranged along the radial direction of the base and supports the lower isolation ring; the lower isolation ring and the lower grounding ring are connected by the first fastener.

3. The lower electrode assembly according to claim 1, characterized in that The top surface of the lower isolation ring is provided with an annular groove corresponding to the position of the upper isolation ring; the lower part of the first elastic insulating ring is located in the annular groove and elastically contacts the side wall of the annular groove; the first fastener passes through the bottom wall of the annular groove.

4. The lower electrode assembly according to claim 3, characterized in that: The lower portion of the upper isolation ring is located in the annular groove.

5. The lower electrode assembly according to claim 1, characterized in that: When the temperature in the reaction chamber is lower than the process temperature, a thermal deformation accommodating gap is provided between the inner side wall of the upper isolation ring and the first elastic insulating ring.

6. The lower electrode assembly according to claim 1, characterized in that The inner side wall of the upper isolation ring is provided with a mounting groove for accommodating the first elastic insulating ring.

7. The lower electrode assembly according to claim 1, characterized in that: The top surface of the first elastic insulating ring is lower than the top surface of the upper isolation ring.

8. The lower electrode assembly according to claim 2, characterized in that: The interior of the facility plate is provided with a plurality of transverse channels and a plurality of first longitudinal channels, and each of the transverse channels is respectively connected to one of the first longitudinal channels; the interior of the base is provided with a plurality of second longitudinal channels, and each of the second longitudinal channels is respectively connected to one of the first longitudinal channels; the transverse channels and the corresponding first longitudinal channels and second longitudinal channels form an electrical channel for supplying power to electrical components around the base.

9. The lower electrode assembly according to claim 8, characterized in that The transverse channel includes a first mounting opening formed on an outer side wall of the facility plate; the first elastic insulating ring covers the first mounting opening.

10. The lower electrode assembly according to claim 8, characterized in that The first longitudinal channel includes a second mounting opening formed on the bottom surface of the facility plate; the lower electrode assembly also includes a second elastic insulating ring; the second elastic insulating ring is arranged between the facility plate and the lower isolation ring and covers the second mounting opening.

11. The lower electrode assembly according to claim 8, characterized in that The electrical component is an edge electrode, and the electrical channel contains a first conductive core for providing a radio frequency signal to the edge electrode.

12. The lower electrode assembly according to claim 11, wherein: The electrical element is a heating element, and the electrical channel contains a second conductive core for supplying power to the heating element.

13. The lower electrode assembly according to claim 12, wherein: An insulating material is filled between the first conductive core and the inner wall of the electrical channel, and between the second conductive core and the inner wall of the electrical channel.

14. The lower electrode assembly according to claim 12, wherein: The base includes a base body and a boss formed on the top of the base body; the lower electrode assembly also includes a focusing ring arranged around the outer periphery of the boss, which is used to control the radio frequency electric field distribution at the edge of the wafer to be processed; the second longitudinal channel is located below the focusing ring; the edge electrode and the heating element are arranged inside the focusing ring, or between the focusing ring and the base body.

15. The lower electrode assembly according to claim 10, wherein: A plurality of third longitudinal channels are provided inside the facility plate; a plurality of fourth longitudinal channels are provided inside the base, and each of the fourth longitudinal channels is connected to a third longitudinal channel respectively; the third longitudinal channels and the corresponding fourth longitudinal channels form an installation channel for a second fastener, and the second fastener is used to fix the base and the facility plate; the third longitudinal channel includes a third installation port formed on the bottom surface of the facility plate; and the second elastic insulating ring covers the third installation port.

16. The lower electrode assembly according to claim 14, wherein: It also includes a middle grounding ring, which surrounds the outer circumference of the upper isolation ring and the lower isolation ring; the middle grounding ring is connected to the top of the lower grounding ring and is arranged along the axial direction of the base.

17. The lower electrode assembly according to claim 16, wherein: It also includes a cover ring; the cover ring is arranged around the outer circumference of the focusing ring and is located above the upper isolation ring and the middle grounding ring to prevent the plasma in the reaction chamber from corroding the components below the cover ring.

18. The lower electrode assembly according to claim 10, wherein: The first elastic insulating ring and the second elastic insulating ring are made of perfluororubber.

19. The lower electrode assembly according to claim 1, wherein: The outer side walls of the base and the facility plate are both provided with a protective layer resistant to plasma corrosion.

20. 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 19.

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