Ground electrode formed in electrostatic chuck for plasma processing chamber

Abstract

Ground electrodes formed in electrostatic chucks for plasma processing chambers are provided. Disclosed herein is a substrate support assembly having a network of ground electrodes disposed in the substrate support assembly along a side surface of the substrate support assembly. The substrate support assembly has a body. The body has an outer top surface, an outer side surface, and an outer bottom surface that enclose an interior of the body. The body has a network of ground electrodes disposed in the interior of the body adjacent to the outer side surface, wherein the ground electrodes do not extend through to the outer side top surface or the outer side surface.

Description

[0001] This application is a divisional application of the invention patent application filed on November 11, 2019, with application number "201911094493.9" and invention title "Grounding electrode formed in an electrostatic chuck for a plasma processing chamber". Technical Field

[0002] The embodiments of this disclosure generally relate to plasma processing chambers. More specifically, embodiments of this disclosure relate to a grounding electrode for a substrate support assembly disposed in a plasma processing chamber. Background Technology

[0003] Plasma processing systems are used to form devices on substrates such as semiconductor wafers or transparent substrates. Typically, the substrate is held to a support for processing. The substrate can be held to the support by vacuum, gravity, electrostatic force, or other suitable techniques. During processing, a precursor gas or gas mixture in a chamber is excited (e.g., agitated) into plasma by applying power (such as radio frequency (RF) power) from one or more power sources coupled to electrodes to electrodes in the chamber. The excited gas or gas mixture reacts to form a material layer on the surface of the substrate. This layer can be, for example, a passivation layer, a gate insulator, a buffer layer, and / or an etch stop layer.

[0004] During plasma-enhanced chemical vapor deposition (PECVD) processes, capacitively coupled plasma, also known as source plasma, is formed between a substrate support and a gas distribution plate. The RF return path of the plasma passes through the substrate support and the chamber liner. Asymmetry in the poorly grounded or broken grounded RF return path can lead to inhomogeneities or skewness in the processing results (e.g., etching, deposition, etc.). A processing chamber typically includes: a substrate support or base disposed within the processing chamber to support the substrate during processing; and a nozzle having a panel for introducing process gases into the processing chamber. The plasma is generated by two RF electrodes, with the nozzle serving as the top electrode (i.e., cathode) and the substrate support serving as the bottom electrode (i.e., anode). In some processes, the base may include an embedded metal mesh to serve as the bottom electrode. Process gases flow through the nozzle, and plasma is generated between the two electrodes. In conventional systems, RF current flows through the plasma from the top electrode of the nozzle to the bottom electrode of the heater. The RF current passes through a nickel RF bar in the base and then returns through the base structure within the chamber walls. The RF return path provides process stability and prevents arcing within the chamber, thereby extending the lifespan of chamber components. However, the vertical walls of the substrate support are largely not properly grounded, and proper grounding can promote the formation of parasitic plasmas beneath the support surface of the substrate support.

[0005] Therefore, what is needed is an improved RF return path in the plasma processing chamber. Summary of the Invention

[0006] This document discloses a substrate support assembly having a ground electrode mesh disposed along a side surface of the substrate support assembly, and a method for forming the ground electrode mesh. The substrate support assembly has a body. The body has an outer top surface, an outer side surface, and an outer bottom surface to surround the interior of the body. The body has a ground electrode mesh disposed within the interior of the body and adjacent to the outer side surface, wherein the ground electrodes do not extend through the outer top surface or the outer side surface.

[0007] This document discloses a method for forming an electrostatic chuck (ESC). The method begins by sintering an aluminum nitride (AlN) or alumina body having a heater, an RF electrode grid, and a high-voltage (HV) ESC electrode grid. A grounding electrode grid is disposed along one or more outer surfaces of the sintered AlN body. The grounding electrode grid and the sintered body are then surrounded in aluminum powder to form the ESC body. The ESC body is sintered to form the ESC.

[0008] This document discloses another method for forming an ESC. The method begins by printing RF electrodes on the top surface of a first AlN sheet. A plurality of first through-holes are formed in the first AlN sheet. A heater is printed on the top surface of a second AlN sheet. A plurality of second through-holes are formed in the second AlN sheet. The second through-holes are vertically aligned with the first through-holes. An HV ESC electrode is printed on the top surface of a third AlN sheet. A plurality of third through-holes are formed in the third AlN sheet. The third through-holes are vertically aligned with the first through-holes. A grounding grid is printed on the top surface of a fourth AlN sheet. A plurality of fourth through-holes are formed in the fourth AlN sheet. The fourth through-holes are vertically aligned with the first through-holes. A fifth AlN sheet is placed on the top surface of the first sheet to obtain the ESC body. Attached Figure Description

[0009] To gain a more detailed understanding of the features described above, a more specific description of the disclosure can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only exemplary embodiments and should not be construed as limiting the scope of the disclosure, and other equivalent embodiments may be permitted.

[0010] Figure 1 This is a schematic cross-sectional view of a process chamber including a substrate support assembly according to one embodiment.

[0011] Figures 2A to 2D This is an embodiment with a substrate support. Figure 1 A schematic cross-sectional view of the substrate support assembly.

[0012] Figures 3A to 3B This is a schematic cross-sectional view of a substrate support according to another embodiment, which can be used to replace... Figure 1 The substrate support.

[0013] Figure 4 According to one embodiment Figure 1 A schematic perspective view of the substrate support assembly and the tube socket.

[0014] Figure 5 This is a schematic cross-sectional view of a process chamber including a substrate support assembly according to the second embodiment.

[0015] Figure 6 This is a partial schematic cross-sectional view of a process chamber including a substrate support assembly according to a third embodiment.

[0016] Figure 7 It is a method used to form ESC.

[0017] Figure 8 This is another method for forming ESC.

[0018] For ease of understanding, the same reference numerals have been used as much as possible to indicate the same elements common to all figures. It is contemplated that elements and / or features of one embodiment may be advantageously incorporated into other embodiments without further description.

[0019] Specific implementation method

[0020] The embodiments of this disclosure generally relate to a vertical direct ground electrode disposed along the periphery of a substrate support in a plasma processing chamber. The substrate support assembly includes a substrate support and a socket. The substrate support has a ceramic body. The ceramic body has an outer vertical wall, a bottom surface, and a support surface. The support surface is configured to support the substrate on the support surface. RF electrodes and a heater are disposed within the ceramic body. Additionally, a vertical direct ground electrode for the plasma RF return path is disposed within the ceramic body along the outer vertical wall. The vertical direct ground electrode is adapted to handle large currents. The vertical direct ground electrode is electrically coupled to a ground electrode in the ceramic body. The socket is attached to the bottom surface of the ceramic body and includes a tubular wall. Grounding is disposed through the socket and couples the vertical direct ground electrode to the plasma RF return path. Advantageously, the vertical direct ground electrode provides proper grounding along the outer vertical wall of the ceramic body outside the RF electrodes and heater. The brazing connection between the socket and the ceramic body allows operation even at temperatures exceeding 650 degrees Celsius. The vertical direct ground electrode reduces or eliminates parasitic plasma below the heater, thus reducing power loss.

[0021] The embodiments described herein are illustrated below with reference to their use in a PECVD system configured to process substrates. However, it should be understood that the disclosed subject matter is applicable in other system configurations, such as etching systems, other chemical vapor deposition systems, physical vapor deposition systems, and any other systems in which the substrate is exposed to plasma within a process chamber. It should also be understood that the embodiments disclosed herein can be adapted for practice in other process chambers configured to process substrates of various sizes and dimensions.

[0022] Figure 1 This is a schematic cross-sectional view of a process chamber 100 including a substrate support assembly 128 according to one embodiment described herein. Figure 1 In the example, process chamber 100 is a PECVD chamber. For example... Figure 1 As shown, the process chamber 100 includes one or more sidewalls 102, a bottom 104, a gas distribution plate 110, and a cover plate 112. The sidewalls 102, bottom 104, and cover plate 112 collectively define a processing volume 106. The gas distribution plate 110 and a substrate support assembly 128 are disposed within the processing volume 106. A substrate 105 can be conveyed in and out of the process chamber 100 via a sealable slit valve opening 108 formed through the sidewalls 102 into the processing volume 106. A vacuum pump 109 is coupled to the chamber 100 to control the pressure within the processing volume 106.

[0023] Gas distribution plate 110 is coupled to cover plate 112 at its periphery. Gas source 120 is coupled to cover plate 112 to supply one or more gases through cover plate 112 to a plurality of gas passages 111 formed in cover plate 112. Gas flows through gas passages 111 and enters processing volume 106 toward substrate receiving surface 132.

[0024] RF power supply 122 is coupled to cover plate 112 and / or directly coupled to gas distribution plate 110 via RF power feed line 124 to provide RF power to gas distribution plate 110. Various RF frequencies can be used. For example, the frequency can be between approximately 0.3 MHz and approximately 200 MHz, such as approximately 13.56 MHz. RF return path 125 couples substrate support assembly 128 to RF power supply 122 through sidewall 102. RF power supply 122 generates an electric field between gas distribution plate 110 and substrate support assembly 128. The electric field is formed by plasma from the gas present between gas distribution plate 110 and substrate support assembly 128. RF return path 125 completes the circuitry for RF energy, preventing RF arcing caused by stray plasma due to voltage difference between substrate support assembly 128 and sidewall 102. Therefore, RF return path 125 mitigates arcing that causes process drift, particulate contamination, and damage to chamber components.

[0025] The substrate support assembly 128 includes a substrate support 130 and a socket 134. The socket 134 is coupled to a lifting system 136 adapted to raise and lower the substrate support assembly 128. The substrate support 130 includes a substrate receiving surface 132 for supporting a substrate 105 during processing. A lifting rod 138 is movably disposed through the substrate support 130 to move the substrate 105 to and from the substrate receiving surface 132 to facilitate substrate transfer. An actuator 114 is used to extend and retract the lifting rod 138. During processing, a ring assembly 133 can be positioned above the periphery of the substrate 105. The ring assembly 133 is configured to prevent or reduce unwanted deposition on surfaces of the substrate support 130 not covered by the substrate 105 during processing.

[0026] The substrate support 130 may further include heating and / or cooling elements 139 to maintain the substrate support 130 and the substrate 105 positioned on the substrate support 130 at a desired temperature. In one embodiment, the heating and / or cooling element 139 may be used to maintain the temperature of the substrate support 130 and the substrate 105 disposed on the substrate support 130 at less than or lower than about 800°C during processing. In one embodiment, the heating and / or cooling element 139 may be used to control the substrate temperature to less than 650°C, such as between 300°C and about 400°C. Figures 2A to 2D and Figures 3A to 3B The substrate support 130 is described in further detail.

[0027] Figures 2A to 2D This is one embodiment having a substrate support 130. Figure 1 A schematic cross-sectional view of the substrate support assembly 128. Figures 2A to 2D Simplified components or constructions of the substrate support assembly 128 are shown at four time snapshots. These figures illustrate the generation of ground electrodes within and along the periphery of the substrate support 130 (i.e., one embodiment of the substrate support 130). Figures 2A to 2D The fabrication of the substrate support 130 will be discussed in turn. However, it should be understood that... Figures 2A to 2D The substrate support 130 depicted can be formed using a variety of different techniques and possibly even different sequences of operations.

[0028] Figure 2A A main body 210 with side surfaces 206, support surfaces 204, and bottom surfaces 205 is shown. A view of the main body 210 is shown in... Figure 2AThe RF mesh 224 is disposed within the body 210. A high-voltage clamping electrode 222 and an optional heater 226 are also disposed within the body 210. The RF mesh 224, the high-voltage clamping electrode 222, and the heater 226 each have individual connections extending through the bottom surface 205 of the body 210. These connections provide individual control and power for each of the RF mesh 224, the high-voltage clamping electrode 222, and the heater 226. The body 210 is made of ceramic material. The body 210 can be formed by sintering ceramic materials such as aluminum nitride (AlN) or alumina powder or other suitable materials. The RF mesh 224 is embedded in the body 210. The RF mesh 224 has electrical connections extending through the bottom surface 205 of the body 210.

[0029] Figure 2B A body 201 surrounded by a ground electrode 228 on a bottom surface 205 and a side surface 206 is shown. The ground electrode 228 may form a continuous cylindrical wall along the side surface 206 around the body 210 or alternatively a cage-like structure. For example, the cage-like structure may be formed by 3 to 24 pins for the ground electrode 228. The diameter of each pin of the ground electrode 228 may be between about 0.5 mm and about 2 mm. The pins are formed of an RF conductive material such as molybdenum. That is, the ground electrode 228 may be continuous internally along the radius of the body 201, or alternatively may be discontinuous internally along the radius. In this way, the ground electrode 228 forms a grounding path completely around the side surface 206 of the ESC 200. The body 201 and the ground electrode 228 are surrounded by a capping layer 238. Contact pads 229 may extend through the capping layer 238 along the mounting surface 232 on the bottom of the ESC body 250 of the substrate support 130. Contact pad 229 is configured to electrically couple ground electrode 228 to RF gasket or other connection. Capping layer 238 may be AlN powder or other suitable ceramic material. Alternatively, capping layer 238 may be another dielectric material suitable for exposure in a plasma processing environment. Ground electrode 228 extends through capping layer 238 at bottom surface 205 of body 210 to provide electrical connection to ground electrode 228. Button 227 may be formed of RF conductive material. Button 227 extends between RF mesh 224 and ground electrode 228 and completes the circuitry between them. Button 227 may be formed of molybdenum or other suitable metallic material. RF mesh 224 embedded in body 201 has an electrical connection extending through capping layer 238 at bottom surface 205 of body 210 to provide electrical connection to RF mesh 224.

[0030] Figure 2CA capping layer 238 is shown encapsulating the ground electrode 228 and the body 210 to form the ESC 130. The capping layer 238 can be sintered to form an integral structure with the body 210. The ESC 130 has an ESC body 250. The ESC body 250 has a support surface 204, a side surface 260, and a mounting surface 232. The mounting surface 232 corresponds to the bottom surface 205 of the body 210. The mounting surface 232 has electrical connections extending through it corresponding to the ground electrode 228. The mounting surface 232 may additionally have electrical connections for one or more of the RF grid 224, the high-voltage clamping electrode 222, and the heater 226, which extend through the mounting surface to provide power and control to the respective RF grid 224, high-voltage clamping electrode 222, and heater 226. The ground electrode 228 and / or contact pads 229 exposed at the bottom may be protected by yttrium, aluminum, nickel, or a nickel-cobalt-iron alloy.

[0031] Figure 2D A mounting surface 232 attached to the ESC body 250 is shown, for forming a socket 134 for the substrate support assembly 128. The socket 280 can be attached using any suitable technique, such as adhesive, mechanical fasteners, brazing, soldering, etc. A corresponding RF mesh 224, high-voltage clamping electrode 222, and heater 226 are electrically coupled to wiring laid within the socket 280. A ground electrode 228 connection can be electrically coupled to the socket 280. Alternatively, the ground electrode 228 may be electrically coupled to wiring or other conductive elements within the socket 280. Reference will be made below. Figure 4 The electrical connection of the grounding electrode 228 in the tube socket 280 is further discussed.

[0032] Figures 3A to 3B This is a schematic cross-sectional view of a substrate support 330 according to another embodiment, which can be used as an alternative. Figure 1 The substrate support 130. The substrate support 330 can be formed by printing, bonding, sintering or forming multiple sheets by one or more suitable techniques, including in a plasma processing chamber (such as one or more deposition chambers, etching chambers, etc.).

[0033] exist Figure 3A In this embodiment, the substrate support 330 is formed of multiple layers. In one embodiment, the substrate support 330 is formed of a first layer 301, a second layer 302, a third layer 303, a fourth layer 304, a fifth layer 305, a sixth layer 306, a seventh layer 307, and an eighth layer 308. It should be understood that the substrate support 330 may be formed of more or fewer than eight layers. However, the above embodiment will be discussed further, wherein the number of layers forming the substrate support 330 is eight.

[0034] The first layer 301 has a first top surface 309, a first bottom surface 371, and a first side surface 361. The second layer 302 has a second top surface 392, a second bottom surface 372, and a second side surface 362. The third layer 303 has a third top surface 393, a third bottom surface 373, and a third side surface 363. The fourth layer 304 has a fourth top surface 394, a fourth bottom surface 374, and a fourth side surface 364. The fifth layer 305 has a fifth top surface 395, a fifth bottom surface 375, and a fifth side surface 365. The sixth layer 306 has a sixth top surface 396, a sixth bottom surface 376, and a sixth side surface 366. The seventh layer 307 has a seventh top surface 397, a seventh bottom surface 377, and a seventh side surface 367. The eighth layer 308 has an eighth top surface 398, an eighth bottom surface 378, and an eighth side surface 368.

[0035] Multiple grounding pads 310 are disposed near the first side surface 361 between the first bottom surface 371 and the second top surface 392. The grounding pads 310 are formed of a conductive material (such as metal). An HV electrode 322 may additionally be disposed between the first bottom surface 371 and the second top surface 392. Multiple through-holes 312 in the second layer 302 are disposed near the second side surface 362 below the multiple grounding pads 310 on the second top surface 392 of the second layer 302. The through-holes 312 are filled with a conductive material (such as the same conductive material as the pads) and are electrically connected to the grounding pads 310. The number of through-holes 312 corresponds to the number of grounding pads 310. In another example, the number of through-holes 312 formed in the second layer 302 is twice the number of grounding pads 310 disposed between the second layer 302 and the first layer 301. It is important to understand that each grounding pad 310 has one or more corresponding through-holes 312 filled with conductive material, which is attached to and electrically coupled to the grounding pad.

[0036] Additional grounding pads 310 are disposed near the second side surface 362 between the second bottom surface 372 and the third top surface 393. Through-holes 312 in the third layer 303 are disposed below the plurality of grounding pads 310 on the third top surface 393 near the third side surface 363. The grounding pads 310 between the second bottom surface 372 and the third top surface 393 are electrically coupled to the through-holes 312 in the second layer 302 and the through-holes in the third layer 303. An RF mesh 324 may be additionally disposed between the second bottom surface 372 and the third top surface 393. In one embodiment, the through-holes 312 in the second layer 302 are aligned with the through-holes 312 in the third layer. However, the alignment of the through-holes 312 in the corresponding second layer 302 and third layer 303 is less important than the conductivity between them. In a second embodiment, the through-holes 312 in the second layer 302 are not aligned with the through-holes 312 in the third layer 303.

[0037] An additional grounding pad 310 is disposed near the fourth side surface 364 between the third bottom surface 373 and the fourth top surface 394. A through-hole 312 in the fourth layer 304 is disposed below the plurality of grounding pads 310 on the fourth top surface 394 near the fourth side surface 364. The grounding pad 310 between the third bottom surface 373 and the fourth top surface 394 is electrically coupled to the through-hole 312 in the third layer 303 and the through-hole 312 in the fourth layer 304. As discussed above, the through-hole 312 in the third layer 303 is electrically coupled to the through-hole 312 in the fourth layer 304 via the grounding pad 310.

[0038] An additional grounding pad 310 is disposed near the fourth side surface 364 between the fourth bottom surface 374 and the fifth top surface 395. A through-hole 312 in the fifth layer 305 is disposed below the plurality of grounding pads 310 on the fifth top surface 395 near the fifth side surface 365. The grounding pad 310 between the fourth bottom surface 374 and the fifth top surface 395 is electrically coupled to the through-hole 312 in the fourth layer 304 and the through-hole 312 in the fifth layer 305. As discussed above, the through-hole 312 in the fourth layer 304 is electrically coupled to the through-hole 312 in the fifth layer 305 via the grounding pad 310.

[0039] An additional grounding pad 310 is disposed near the fifth side surface 365 between the fifth bottom surface 375 and the sixth top surface 396. A through-hole 312 in the sixth layer 306 is disposed below the plurality of grounding pads 310 on the sixth top surface 396 near the sixth side surface 366. The grounding pad 310 between the fifth bottom surface 375 and the sixth top surface 396 is electrically coupled to the through-hole 312 in the sixth layer 306 and the through-hole in the fifth layer 305. A heater coil 326 may optionally be disposed between the fifth bottom surface 375 and the sixth top surface 396. As discussed above, the through-hole 312 in the fifth layer 305 is electrically coupled to the through-hole 312 in the sixth layer 306 via the grounding pad 310.

[0040] An additional grounding pad 310 is disposed near the sixth side surface 366 between the sixth bottom surface 376 and the seventh top surface 397. A through-hole 312 in the seventh layer 307 is disposed below the plurality of grounding pads 310 on the seventh top surface 397 near the seventh side surface 367. The grounding pad 310 between the sixth bottom surface 376 and the seventh top surface 397 is electrically coupled to the through-hole 312 in the sixth layer 306 and the through-hole 312 in the seventh layer 307. As discussed above, the through-hole 312 in the sixth layer 306 is electrically coupled to the through-hole 312 in the seventh layer 307 via the grounding pad 310.

[0041] A ground electrode 328 is disposed between a seventh bottom surface 377 and an eighth top surface 398. The ground electrode 328 extends to an eighth side surface 368. An eighth layer 308 has a center 399. The ground electrode 328 extends through the center 399 for electrical connection to the center. A through-hole 312 may additionally extend through the eighth layer 308. A ground pad 329 may be electrically coupled to the ground electrode 328 through the through-hole 312. The ground pad 329 is configured to electrically couple the ground electrode 328 to an RF gasket or other connection. The HV electrode 322, RF mesh 324, and heater coil 326 have electrical connections extending through the center 399 to provide power and control to the respective HV electrode 322, RF mesh 324, and heater 386. The ground electrode 328 and / or ground pad 329 exposed at the bottom may be protected by yttrium, aluminum, nickel, or a nickel-cobalt-iron alloy.

[0042] Figure 3B An ESC 330 formed from the components of the first layer 301 to the eighth layer 308 discussed above is shown. Through-holes 312 with electrical coupling are arranged between the first layer 301 and the eighth layer 308, and ground pads 310 with adjacent side surfaces 360 are disposed within the ESC 330. Each of the plurality of through-holes 312 and each ground pad 310 forms a grounding path through the adjacent side surface 360 ​​of the ESC 330. The through-holes 312 are substantially orthogonal to the substrate support surface 350 of the ESC 330. The through-holes 312 and ground pads 310 are arranged in a cylindrical pattern within the body of the ESC 330. The through-holes 312 and ground pads 310 can form continuous cylindrical walls or alternatively, cage-like structures. For example, the cage-like structure can be formed by 3 to 24 pin-like structures for the through-holes 312. The diameter of each through-hole 312 can be between about 0.5 mm and about 2 mm. The via can be filled with metal to form a continuous conductive path. Alternatively, the via 312 can be continuous along the radius of the ESC 330. In this way, the via 312 forms a grounding path that completely surrounds the side surface 360 ​​of the ESC 330.

[0043] Now refer to Figure 4 The electrical coupling from grounding electrode 228 / 328 to the pipe socket is discussed. Figure 4 According to one embodiment Figure 1 A schematic perspective view of the substrate support assembly 128. Figures 3A to 3B The ESC 330 is equally suitable for... Figure 4 The substrate support assembly 128 and electrical grounding connection are discussed. The socket 134 can be attached to the ESC 130 / 330 using a variety of suitable techniques for forming the substrate support assembly 128. For example, the socket 134 can be soldered, chemically bonded, or mechanically bonded to the ESC 130 / 330. In one embodiment, the socket 134 is diffusely bonded to the ESC 130 / 330.

[0044] The socket 134 has a hollow interior 434. A metallic grounding conduit 442 is disposed within the hollow interior 434 of the socket 134. The metallic grounding conduit 442 is a cylindrical metal body. The metallic grounding conduit 442 may be formed of a molybdenum or nickel-cobalt-iron alloy coated with Mo, Au, or Ag, or other suitable materials. The metallic grounding conduit 442 has an internal region 444. The internal region 444 is configured to provide space for an electrical connection to ESC 130 to pass through the metallic grounding conduit 442. An RF grounding coaxial return (in) is provided for the grounding grid 228 / 328 through the metallic grounding conduit 441. Figures 2A to 2D and Figure 3B (As shown in the diagram). The metal grounding conduit 442 has a plurality of grounding conduit connectors 420. The grounding conduit connectors 420 are configured to mate with corresponding mesh connectors 410, as indicated by arrow 415. The grounding conduit connectors 420 may be tabs or protrusions in the metal grounding conduit 442. The grounding conduit connectors 420 may be fitted into the corresponding mesh connectors 410 to provide an electrical connection to the grounding mesh 228 / 238 to complete a grounding path. In one embodiment, the grounding electrode 228 is brazed to the grounding conduit connector 420 to complete a ground return path located within the sides 260 / 360 of the ESC 130 / 330. Thus, RF shielding is created at the bottom and edges of the substrate support 130 by a shielding effect, where RF will be present on the wiring within the shaft, heater, and RF mesh.

[0045] Figure 5 This is a schematic cross-sectional view of a processing chamber 500 including a substrate support assembly 128 according to a second embodiment. The processing chamber 500 has a body 501. The body 501 has sidewalls 502, a bottom 504, and a cover plate 512. The sidewalls 502, bottom 504, and cover plate 512 define an internal volume 506 of the processing chamber 500. The substrate support assembly 128 is disposed within the internal volume 506 of the processing chamber 500. Plasma 142 can be formed in the internal volume and maintained by RF energy supplied via the processing chamber 500.

[0046] The substrate support assembly 128 has an ESC 530 and a metal ground tube 560. A clamping electrode 528 is disposed within the ESC 530. A metal coating 554 is disposed on the outer surface of the substrate support assembly 128. The metal coating 554 may be formed of molybdenum, aluminum, copper, or other suitable conductive materials. The metal coating 554 is electrically coupled to the RF ground loop.

[0047] The metal grounding conduit 560 can be formed of molybdenum, aluminum, copper, or other suitable conductive materials. The metal grounding conduit 560 is electrically coupled to the RF grounding loop. One or more RF washers 550, 552 can be disposed between the metal grounding conduit 560 and a chamber component that is part of the RF grounding path. The RF washers 550, 552 are conductive to and transmit RF energy to form the RF grounding circuit. The RF washers 550, 552 can be formed of nickel, copper, aluminum, molybdenum, or other suitable materials. The RF washer 550 is disposed between the metal grounding conduit 560 and the sidewall 502 or cover 512 of the processing chamber 500. Additionally, the RF washer 552 can be disposed between the metal grounding conduit 560 and a metal coating 554 to couple RF energy between them. Advantageously, the RF ground return path can be short to reduce resistance in the grounding path and reduce voltage drop between the individual chamber components to prevent arcing.

[0048] Figure 6 This is a partial schematic cross-sectional view of a processing chamber 600 including a substrate support assembly 128 according to a third embodiment. The processing chamber 600 has a body 601. The body has sidewalls 602, a bottom 604, and a nozzle 612. The sidewalls 602, bottom 604, and nozzle 612 define an internal volume 606. The substrate support assembly 128 is disposed within the internal volume 606. An RF generator 680 is coupled to electrodes 682 in the nozzle 612. The RF generator 680 has an RF return path 688 for completing RF circuitry in the presence of plasma.

[0049] The substrate support assembly 128 has a heater 626, an HV clamping mesh 622, and an RF mesh 624 disposed within it. The substrate support assembly 128 has an outer surface 629. A metal coating 684 is disposed on the outer surface 629 of the substrate support assembly 128. The metal coating 684 is formed of nickel, copper, aluminum, molybdenum, or other suitable materials. The metal coating 684 is part of the RF return path 688 and completes RF grounding when the RF generator 680 is energized. A protective coating 632 may be disposed on the metal coating 684 to protect it from corrosion and help maintain its conductivity. The protective coating 632 may be formed of yttrium oxide, AlN, Al2O3, or other suitable materials. The protective coating 632 maintains the connection of the RF grounding path for the substrate support assembly 128. Advantageously, the RF grounding path for maintaining plasma can be maintained and provide a longer service life for the substrate support assembly 128.

[0050] Figure 7This is method 700 for forming an ESC. Method 700 begins at operation 710 by sintering an AlN body having a heater, an RF electrode mesh, and an HV ESC electrode mesh. At operation 720, a ground electrode mesh is disposed along one or more outer surfaces of the sintered AlN body. At operation 730, the ground electrode mesh and the sintered body are encapsulated in aluminum powder to form the ESC body. At operation 740, the ESC body is sintered to form the ESC.

[0051] Figure 8 This is another method 800 for forming an ESC. Method 800 begins at operation 810 by printing an HV ESC electrode on the top surface of a first AlN sheet. At operation 830, a ground plane electrode is printed on the top surface of a second ceramic sheet. At operation 840, a plurality of second through-holes are formed in the second ceramic sheet and connected to the ground plane electrode. At operation 850, one or more heater electrodes are printed on the top surface of a third ceramic sheet. At operation 860, a plurality of third through-holes are formed in the third ceramic sheet, the third through-holes being vertically aligned with the second through-holes. At operation 870, a grounding grid is printed on the top surface of a fourth ceramic sheet. The grounding grid is electrically coupled to the ground plane electrode through through-holes. At operation 880, a plurality of fourth through-holes are formed in the fourth ceramic sheet, the fourth through-holes being vertically aligned with the second through-holes. At operation 890, a fifth ceramic sheet is placed on the top surface of the first sheet to obtain the ESC body.

[0052] Although the foregoing describes embodiments of this disclosure, other and further embodiments of this disclosure may be conceived without departing from the basic scope of this disclosure, the scope of which is defined by the appended claims.

Claims

1. A method for forming an ESC, the method comprising: HV ESC electrodes are printed on the top surface of a first ceramic sheet, the first ceramic sheet having a first through-hole filled with conductive material. A cylindrical ground plane RF electrode is printed on the top surface of the second ceramic sheet; A second through-hole is formed in the second ceramic sheet, the second through-hole is filled with a conductive material and connected to the cylindrical ground plane RF electrode; Heater electrodes are printed on the top surface of the third ceramic sheet; A third through-hole is formed in the third ceramic sheet, the third through-hole being filled with a conductive material and vertically aligned with the second through-hole; A grounding grid is printed on the top surface of the fourth ceramic sheet; A fourth through hole is formed in the fourth ceramic sheet, the fourth through hole being filled with a conductive material and vertically aligned with the second through hole; as well as A fifth ceramic sheet is placed on the top surface of the first ceramic sheet to form the ESC.

2. The method of claim 1, wherein the cylindrical ground plane electrode is continuous along the radius of the ESC body.

3. The method of claim 1, wherein the cylindrical grounding plane electrode is a vertical cage shape disposed in the ESC.

4. The method of claim 1, further comprising: A plurality of pads are formed between the first through-hole and the second through-hole, wherein the pads are electrically coupled to the conductive material in the first through-hole and the second through-hole.

5. The method of claim 1, further comprising: A metal grounding tube is attached to the cylindrical grounding plane electrode, wherein the metal grounding tube is disposed in a tube socket attached to the ESC body.

6. The method of claim 5, wherein the metal grounding tube has a plurality of grounding tube connectors connected to corresponding mesh connectors attached to the cylindrical grounding plane electrode.

7. The method of claim 5, wherein the grounding connector is a tab or protrusion.

8. A method for forming an ESC, the method comprising: HV ESC electrodes are printed on the top surface of a first aluminum nitride (AlN) sheet, the first AlN sheet having a first through-hole filled with a conductive material. A cylindrical ground plane RF electrode is printed on the top surface of the second AlN sheet; A second through-hole is formed in the second AlN sheet, the second through-hole is filled with a conductive material and connected to the cylindrical ground plane RF electrode; Heater electrodes are printed on the top surface of the third AlN sheet; A third through-hole is formed in the third AlN sheet, the third through-hole being filled with a conductive material and vertically aligned with the second through-hole; A grounding mesh is printed on the top surface of the fourth AlN sheet; A fourth through-hole is formed in the fourth AlN sheet, the fourth through-hole being filled with a conductive material and vertically aligned with the second through-hole; A fifth AlN sheet is placed on the top surface of the first AlN sheet to form the ESC; The first AlN sheet to the fifth AlN sheet are sintered to form the ESC.

9. The method of claim 8, wherein the cylindrical ground plane electrode is continuous along the radius of the ESC body.

10. The method of claim 8, wherein the cylindrical grounding plane electrode is a vertical cage shape disposed in the ESC.

11. The method of claim 8, further comprising: A plurality of pads are formed between the first through-hole and the second through-hole, wherein the pads are electrically coupled to the conductive material in the first through-hole and the second through-hole.

12. The method of claim 8, further comprising: A metal grounding tube is attached to the cylindrical grounding plane electrode, wherein the metal grounding tube is disposed in a tube socket attached to the ESC body.

13. The method of claim 12, wherein the metal grounding tube has a plurality of grounding tube connectors connected to corresponding mesh connectors attached to the cylindrical grounding plane electrode.

14. The method of claim 12, wherein the grounding connector is a tab or protrusion.

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