Ceramic electrostatic chuck with embedded Faraday cage for RF delivery and associated methods for operation, monitoring, and control

Abstract

To provide an electrostatic chuck and a manufacturing method thereof.SOLUTION: In a plasma processing chamber used in semiconductor chip fabrication processes, an electrostatic chuck 107A formed of a ceramic material as a ceramic assembly is attached to a lower support structure 109 having a bowl shape, and supports a substrate 105. At least one clamp electrode 201 is positioned within an upper region of the ceramic assembly. A primary radio frequency (RF) power delivery electrode 203 is positioned within the ceramic assembly at a location vertically below the at least one clamp electrode such that a region between the primary RF power delivery electrode and the at least one clamp electrode is substantially free of other electrically conductive material. A plurality of RF power delivery connection modules 629 are distributed in a substantially uniform manner about a perimeter of the ceramic assembly. Each of the RF power delivery connection modules forms an electrical connection from the lower support structure to the primary RF power delivery electrode at its respective locations.SELECTED DRAWING: Figure 6A

Description

[Background technology]

[0001] The present invention relates to the manufacture of semiconductor devices.

[0002] Many modern semiconductor chip manufacturing processes are performed in plasma processing chambers in which a substrate, e.g., a wafer, is supported by an electrostatic chuck. In some cases, a radio frequency (RF) signal is transmitted through the electrostatic chuck to generate a plasma and / or provide RF bias in a region above the electrostatic chuck. The RF signal is typically transmitted to the bottom of the electrostatic chuck and passes through the internal structure of the electrostatic chuck by capacitive coupling to reach the region above the electrostatic chuck. The internal structure of an electrostatic chuck can vary from one chuck to another, causing the transmission of the RF signal through the electrostatic chuck to differ from chuck to chuck. The internal structure of an electrostatic chuck can also vary azimuthally, causing azimuthal non-uniformity in the transmission of the RF signal through the electrostatic chuck. It is in this context that the present invention is conceived. Summary of the Invention

[0003] In one example embodiment, an electrostatic chuck is disclosed. The electrostatic chuck includes a ceramic assembly having an upper surface including an area configured to support a substrate. The electrostatic chuck also includes at least one clamping electrode positioned within the ceramic assembly in an orientation substantially parallel to the upper surface of the ceramic assembly and at an upper position within the ceramic assembly, such that a region of the ceramic assembly between the at least one clamping electrode and the upper surface of the ceramic assembly is substantially free of other conductive materials. The electrostatic chuck also includes a main radio frequency (RF) power supply electrode positioned within the ceramic assembly in an orientation substantially parallel to the upper surface of the ceramic assembly and at a position vertically below the at least one clamping electrode, such that a region of the ceramic assembly between the main RF power supply electrode and the at least one clamping electrode is substantially free of other conductive materials. The main RF power supply electrode is configured to extend horizontally within the ceramic assembly to span at least the entire area of the upper surface of the ceramic assembly below the area configured to support a substrate. The electrostatic chuck also includes a lower support structure formed of a conductive material. The lower support structure has a bowl shape formed by a bottom member and an annular wall member extending upward from the bottom member. The ceramic assembly is secured to the lower support structure such that an outer circumferential region of the bottom surface of the ceramic assembly is supported by an upper surface of the annular wall member of the lower support structure and an interior region of the lower support structure is exposed to a portion of the bottom surface of the ceramic assembly. The electrostatic chuck also includes a plurality of RF power supply connection modules substantially uniformly distributed around the periphery of the ceramic assembly. Each of the plurality of RF power supply connection modules is configured to form an electrical connection from the lower support structure to the main RF power supply electrode at its respective location to form an RF power transmission path from the lower support structure to the main RF power supply electrode at its respective location. The lower support structure, the plurality of RF power supply connection modules, and the main RF power supply electrode collectively form a Faraday cage for directing RF power transmission around the interior region of the electrostatic chuck.

[0004] In one example embodiment, a system for plasma processing is disclosed. The system includes a processing chamber, an electrostatic chuck, and an RF power source. The electrostatic chuck is positioned within the processing chamber. The electrostatic chuck includes a ceramic assembly having an upper surface including an area configured to support a substrate. The electrostatic chuck also includes at least one clamping electrode positioned within the ceramic assembly in an orientation substantially parallel to the upper surface of the ceramic assembly and at a position above the upper surface, such that a region of the ceramic assembly between the at least one clamping electrode and the upper surface of the ceramic assembly is substantially free of other conductive materials. The electrostatic chuck also includes a main RF power supply electrode positioned within the ceramic assembly in an orientation substantially parallel to the upper surface of the ceramic assembly and at a position vertically below the at least one clamping electrode, such that a region of the ceramic assembly between the main RF power supply electrode and the at least one clamping electrode is substantially free of other conductive materials. The main RF power supply electrode is configured to extend horizontally within the ceramic assembly to span at least the entire area of the upper surface of the ceramic assembly below the area configured to support a substrate. The electrostatic chuck also includes a lower support structure formed of a conductive material. The lower support structure has a bowl shape formed by a bottom member and an annular wall member extending upward from the bottom member. The ceramic assembly is secured to the lower support structure such that an outer circumferential region of the bottom surface of the ceramic assembly is supported by an upper surface of the annular wall member of the lower support structure and an inner region of the lower support structure is exposed to a portion of the bottom surface of the ceramic assembly. The electrostatic chuck also includes a plurality of RF power supply connection modules substantially uniformly distributed around the periphery of the ceramic assembly. Each of the plurality of RF power supply connection modules is configured to form an electrical connection from the lower support structure to the main RF power supply electrode at its respective location to form an RF power transmission path from the lower support structure to the main RF power supply electrode at its respective location. The RF power source is configured to transmit RF power to the lower support structure of the electrostatic chuck.The lower support structure, the plurality of RF power supply connection modules, and the main RF power supply electrode collectively form a Faraday cage for directing RF power transmission around the interior region of the electrostatic chuck.

[0005] In one example embodiment, a method for manufacturing an electrostatic chuck is disclosed. The method includes forming a ceramic assembly having an upper surface including an area configured to support a substrate. Forming the ceramic assembly includes positioning at least one clamping electrode within the ceramic assembly in an orientation substantially parallel to the upper surface of the ceramic assembly and at a location above the upper surface, such that a region within the ceramic assembly between the at least one clamping electrode and the upper surface of the ceramic assembly is substantially free of other conductive materials. Forming the ceramic assembly also includes positioning a main RF power supply electrode within the ceramic assembly in an orientation substantially parallel to the upper surface of the ceramic assembly and at a location vertically below the at least one clamping electrode, such that a region within the ceramic assembly between the main RF power supply electrode and the at least one clamping electrode is substantially free of other conductive materials. The main RF power supply electrode is configured to extend horizontally within the ceramic assembly to span at least the entire area of the upper surface of the ceramic assembly below the area configured to support the substrate. Forming the ceramic assembly also includes positioning a plurality of RF power supply connection modules substantially uniformly distributed around the periphery of the ceramic assembly. Each of the plurality of RF power supply connection modules is configured to form an electrical connection from the lower support structure to the main RF power supply electrode at its respective location to form an RF power transmission path from the lower support structure to the main RF power supply electrode at its respective location. The method also includes attaching the ceramic assembly to the lower support structure. The lower support structure is formed of a conductive material. The lower support structure has a bowl shape formed by a bottom member and an annular wall member extending upward from the bottom member. The ceramic assembly is attached to the lower support structure such that an outer periphery region of the bottom surface of the ceramic assembly is supported by an upper surface of the annular wall member of the lower support structure and an interior region of the lower support structure is exposed to a portion of the bottom surface of the ceramic assembly.The lower support structure, the plurality of RF power supply connection modules, and the main RF power supply electrode collectively form a Faraday cage for directing RF power transmission around the interior region of the electrostatic chuck. [Brief explanation of the drawings]

[0006] [Figure 1] 1 illustrates a system for plasma processing including a plasma processing chamber, according to some embodiments of the present invention.

[0007] [Figure 2A] FIG. 1 illustrates a ceramic material of an electrostatic chuck configured to include one or more clamping electrodes, a main RF powered electrode, and one or more resistive heaters, according to some embodiments of the present invention.

[0008] [Figure 2B] 2B illustrates the configuration of FIG. 2A with RF signal transmission paths indicated by thick solid lines, in accordance with some embodiments of the present invention.

[0009] [Figure 3A] 2B is a cross-sectional view of an electrostatic chuck taken at the interface between the main RF power supply electrode and the plurality of RF power supply connection modules corresponding to view AA referenced in FIG. 2A, according to some embodiments of the present invention.

[0010] [Figure 3B] FIG. 3B illustrates a modified version of the main RF powered electrode of FIG. 3A, where the main RF powered electrode is radially symmetrically interleaved about the centerline of the electrostatic chuck, in accordance with some embodiments of the present invention.

[0011] [Figure 3C] FIG. 3B illustrates a modified version of the main RF powered electrode of FIG. 3A, where the main RF powered electrode is spaced radially symmetrically about the centerline of the electrostatic chuck, in accordance with some embodiments of the present invention.

[0012] [Figure 4] 1 is a cross-sectional view of one of a plurality of RF power supply connection modules according to some embodiments of the present invention.

[0013] [Figure 5] FIG. 10 illustrates an example of using four vertical conductive structures between two adjacent interior buried conductive segments in a redundant manner, according to some embodiments of the present invention.

[0014] [Figure 6A] FIG. 1 illustrates an electrostatic chuck formed of a ceramic material having a stepped configuration, in accordance with some embodiments of the present invention.

[0015] [Figure 6B] FIG. 2 is a top view of an electrostatic chuck, according to some embodiments of the present invention.

[0016] [Figure 6C] 1 is a cross-sectional view of one of a plurality of RF power supply connection modules according to some embodiments of the present invention.

[0017] [Figure 6D] FIG. 1 is a longitudinal cross-sectional view of one of a plurality of RF power supply connection modules, where a first electrical connection is electrically isolated from the lower support structure such that independently controlled RF signals can be transmitted to each of the plurality of RF power supply connection modules and the lower support structure, according to some embodiments of the present invention.

[0018] [Figure 7] 1 is a flowchart illustrating a method for determining RF current delivery in a plasma processing process, in accordance with some embodiments of the present invention.

[0019] [Figure 8]1 is a flowchart illustrating a method for manufacturing an electrostatic chuck, in accordance with some embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] In the following description, numerous specific details are set forth to provide a thorough understanding of the embodiments presented. However, it will be apparent to one skilled in the art that the present invention may be practiced without some or all of these specific details. Additionally, detailed descriptions of well-known process steps are omitted so as not to unnecessarily obscure the present invention.

[0021] FIG. 1 illustrates a system for plasma processing including a plasma processing chamber according to some embodiments of the present invention. The plasma processing chamber 100 includes an exterior structure 101 defined by one or more sidewalls 101A, a top structure 101B, and a bottom structure 101C. In some embodiments, the exterior structure 101 of the plasma processing chamber 100 can be formed of a conductive material and can have an electrical connection to a reference ground potential. In some embodiments, the plasma processing chamber 100 can include an openable access passage 103 through which a substrate 105 can be passed into and out of the plasma processing chamber 100. In other embodiments, an upper portion of the processing chamber 100 can be separated from a lower portion of the processing chamber 100 to allow the substrate 105 to be introduced and removed.

[0022] The plasma processing chamber includes an electrostatic chuck 107 disposed on a lower support structure 109. The electrostatic chuck 107 is formed as a ceramic assembly. In some embodiments, the electrostatic chuck 107 includes multiple layers of ceramic and other interior materials assembled and co-fired in a stack. The lower support structure 109 is formed of a conductive material and has a bowl shape formed by a bottom plate member 109B and an annular wall member 109C extending upward from the bottom plate member 109B. The ceramic assembly of the electrostatic chuck 107 is secured to the lower support structure 109 such that an outer circumferential region of the bottom surface of the ceramic assembly of the electrostatic chuck 107 is supported by an upper surface of the annular wall member 109C of the lower support structure 109, and an interior region of the lower support structure 109 is exposed to a portion of the bottom surface of the ceramic assembly of the electrostatic chuck 107.

[0023] In some embodiments, the lower support structure 109 includes an upper flange structure 109A configured to support the electrostatic chuck 107 around the periphery of its lower surface. In some embodiments, the lower support structure 109 and its upper flange structure 109A are formed of aluminum. However, in other embodiments, the lower support structure 109 and its upper flange structure 109A can be formed of other materials or combinations of materials, so long as they provide sufficient electrical conductivity, thermal conductivity, and mechanical strength to support the operation of the electrostatic chuck 107. The upper surface of the electrostatic chuck 107 includes an area configured to support the substrate 105 during processing. In some embodiments, the upper surface of the electrostatic chuck 107 is formed by coplanar upper surfaces of a plurality of raised structures, referred to as mesa structures. With the substrate 105 supported on the upper surfaces of the mesa structures, the areas between the side surfaces of the mesa structures provide a flow of fluid, such as helium gas, to the backside of the substrate 105, allowing for improved temperature control of the substrate 105.

[0024] The plasma processing chamber 100 further includes an upper electrode 117 disposed above the electrostatic chuck 107 such that a plasma processing region 119 exists between the upper electrode 117 and the electrostatic chuck 107. In some embodiments, the upper electrode 117 is electrically connected to a reference ground potential 125. A process gas supply line 121 is plumbed to supply process gas from a process gas source 123 to the plasma processing region 119. In some embodiments, the process gas supply line 121 is configured to simply discharge process gas at one or more locations within the plasma processing chamber 100. In some embodiments, the upper electrode 117 is defined as a showerhead electrode including multiple internal passages leading to multiple outlets, and the process gas supply line 121 is plumbed to an input of the showerhead electrode such that the process gas flows through the multiple internal passages to the multiple outlets and into the plasma processing region 119 in a distributed manner.

[0025] An RF power source 129 is connected to supply an RF signal to the connection 127 through a matching module 131, and the connection 127 is configured to transmit the supplied RF signal to the lower support structure 109. In operation, process gases are flowed into the plasma processing region 119, and an RF signal is supplied to the lower support structure 109. The RF signal is transmitted from the lower support structure 109 through the electrostatic chuck 107, then through the plasma processing region 119 to the upper electrode 117. The RF signal converts the process gases in the plasma processing region 119 into a plasma 133 that irradiates the substrate 105, whereby reactive components of the plasma 133, such as ions and / or radicals, act to modify the irradiated portions of the substrate 105. In some embodiments, gases within the processing chamber 100 flow from the plasma processing region 119 through a side vent 135 to an exhaust 137, which is piped through a connection 138 to an exhaust module 139 configured to draw fluid from the interior space of the processing chamber 100.

[0026] It should be understood that the plasma processing chamber 100 is depicted in a simplified manner herein for ease of explanation. In reality, the plasma processing chamber 100 includes many components not described herein. However, for the purposes of this discussion, it should be understood that the plasma processing chamber 100 is connected to receive a controlled flow of one or more process gas compositions under carefully controlled conditions and includes an electrostatic chuck 107 for holding a substrate 105, where the electrostatic chuck 107 is connected to transmit an RF signal to the plasma processing region 119 to convert the one or more process gas compositions into a plasma 133 to enable processing of the substrate 105 in a specified manner and / or to enable RF biasing of the plasma 133 in the plasma processing region 119 above the electrostatic chuck 107. Examples of plasma processing processes that may be performed by the plasma processing chamber 100 include etching processes, deposition processes, and ashing processes, among others.

[0027] The plasma processing chamber 100 is an example of a type of capacitively coupled plasma (CCP) processing chamber that utilizes an electrostatic chuck 107. However, it should be understood that the electrostatic chuck 107 can also be utilized in other types of plasma processing chambers, such as inductively coupled plasma (ICP) processing chambers and transducer coupled plasma (TCP) processing chambers, in which an RF signal can be transmitted from the electrostatic chuck 107 to a plasma processing region above a substrate held by the electrostatic chuck 107. This disclosure is primarily directed to improvements in the design and operation of the electrostatic chuck 107. Thus, the various example embodiments of the electrostatic chuck 107 disclosed herein can be utilized in essentially any type of plasma processing chamber, with the plasma processing chamber 100 of FIG. 1 providing one example for purposes of discussion.

[0028] In one example embodiment, the term substrate 105 as used herein refers to a semiconductor wafer. However, in other embodiments, the term substrate 105 as used herein can refer to a substrate formed of sapphire, GaN, GaAs, or SiC, or other substrate materials, and can include a glass panel / substrate, a metal foil, a metal sheet, a polymer material, etc. Also, in various embodiments, the substrate 105 as used herein can have a variety of forms, shapes, and / or sizes. For example, in some embodiments, the substrate 105 as used herein can correspond to a 200 mm (millimeter) semiconductor wafer, a 300 mm semiconductor wafer, or a 450 mm semiconductor wafer. Also, in some embodiments, the substrate 105 as used herein can correspond to a non-circular substrate, such as a rectangular substrate for a flat panel display, among other things.

[0029] 2A illustrates a ceramic material of an electrostatic chuck 107 configured to include one or more clamping electrode(s) 201, a main RF power supply electrode 203, and one or more resistive heaters 205, according to some embodiments of the present invention. In some embodiments, the one or more clamping electrodes 201 can be a single electrode used to generate an electric field to hold the substrate 105 on the upper surface of the electrostatic chuck 107. In some embodiments, the one or more clamping electrodes 201 can include two separate clamping electrodes configured for bipolar operation, where a differential voltage is applied between the two separate clamping electrodes to generate an electric field to hold the substrate 105 on the upper surface of the electrostatic chuck 107. In various embodiments, the two separate clamping electrodes can be geometrically interdigitated or interleaved to enable bipolar operation. In some embodiments, the one or more clamping electrodes 201 can include three or more separate clamping electrodes connected to operate in a multi-phase manner. Each electrode of the one or more clamping electrodes 201 is connected to a DC voltage supply 132 through a connection 134. In some embodiments, one or more capacitors 136 may be electrically connected between the one or more clamping electrodes 201 and the lower support structure 109 to provide filtering of the RF signal. The DC voltage supply 132 is configured to control the voltage present on the one or more clamping electrodes 201. In embodiments in which the one or more clamping electrodes 201 include multiple separate clamping electrodes, each electrode of the multiple separate clamping electrodes is connected to the DC voltage supply 132 (or to a separate DC voltage supply 132) such that its voltage and / or phase is controlled in an independent manner relative to the other one or more clamping electrodes 201.

[0030] In some embodiments, a perimeter seal 207 is disposed between the bottom surface of the electrostatic chuck 107 and the top surface of the lower support structure 109. The perimeter seal 207 is configured to prevent plasma 133 components and / or process by-product materials from entering regions within the lower support structure 109.

[0031] In various embodiments, the electrostatic chuck 107 can be configured to include various cooling mechanisms, heating mechanisms, clamping mechanisms, bias electrodes, substrate lift pins, and sensors, where the sensors can provide measurements of temperature, pressure, voltage, and / or current, among other parameters. For example, the ceramic of the electrostatic chuck 107 can be configured to include multiple cooling passages 211 through which a cooling fluid can flow. The ceramic of the electrostatic chuck 107 can also include a fluid channel arrangement through which a backside gas can be channeled and discharged into the regions between the mesa structures below the substrate 105. It will be appreciated that the lower support structure 109 can be configured to hold various circuitry, piping, control components, and support parts for the internal components of the electrostatic chuck 107, such as one or more resistive heaters 205, a backside gas delivery system, substrate lift pins, one or more clamping electrodes 201, cooling passages 211, sensors, etc.

[0032] For purposes of discussion, consider an embodiment of the electrostatic chuck 107 without a main RF power supply electrode 203. In this embodiment, for high frequency RF power applications, e.g., RF frequencies of about 1 MHz or greater, one or more clamping electrodes 201 would be relied upon to distribute the RF signal to the plasma processing region 119. For example, in some cases, the RF signal would be applied to the lower support structure 109 by relying on capacitive coupling of the RF signal through the electrostatic chuck 107 to the one or more clamping electrodes 201 and ultimately to the plasma processing region 119. However, in this case, transmitting the RF signal through the interior of the electrostatic chuck 107 has associated challenges. For example, transmitting the RF signal through the interior of the electrostatic chuck 107 can potentially generate unwanted (parasitic) plasma within various interior regions of the electrostatic chuck 107, which could damage and / or dechucking the substrate 105. Additionally, RF signals transmitted through the interior of the electrostatic chuck 107 may couple through elements of one or more of the resistive heaters 205, causing non-uniformity in the RF current distribution reaching the plasma processing region 119 and thus adversely affecting process uniformity, e.g., etch uniformity and critical dimension uniformity. RF signals transmitted through the interior of the electrostatic chuck 107 may also damage various circuitry therein, including, among other things, the drive circuitry for one or more of the resistive heaters 205. Furthermore, for low-frequency RF power applications, e.g., RF frequencies below about 1 MHz, the electrostatic chuck 107 behaves like a high-impedance insulator to RF signals. Therefore, for low-frequency RF power applications, it is difficult to rely on transmission of low-frequency RF signals from the lower support structure 109 through the ceramic of the electrostatic chuck 107 to the plasma processing region 119 without including a parallel coupling mechanism, such as an external capacitor.

[0033] The presence of the main RF power delivery electrode 203 within the electrostatic chuck 107 eliminates the need to transmit RF signals through problematic internal regions of the electrostatic chuck 107 and eliminates the need to electrically connect one or more clamp electrodes 201 for direct RF power transmission. The main RF power delivery electrode 203 provides safe and reliable RF signal transmission to the plasma processing region 119 over a wide frequency range, including lower and higher RF signal frequencies.

[0034] 2A , the main RF power supply electrode 203 is positioned within the ceramic of the electrostatic chuck 107 in an orientation substantially parallel to the top surface of the electrostatic chuck 107 and at a location vertically below the one or more clamping electrodes 201, such that the region of the electrostatic chuck 107 between the main RF power supply electrode 203 and the one or more clamping electrodes 201 is substantially free of other conductive material. The main RF power supply electrode 203 is also configured to extend horizontally within the ceramic of the electrostatic chuck 107 to span at least the entire area of the top surface of the electrostatic chuck 107 below the area configured to support the substrate 105. The main RF power supply electrode 203 is located near the top of the electrostatic chuck 107 to optimize reactive capacitance. 2A , the one or more clamping electrodes 201 are positioned within the ceramic of the electrostatic chuck 107 in an orientation substantially parallel to the top surface of the electrostatic chuck 107 and at an elevated position within the ceramic of the electrostatic chuck 107, such that the region between the one or more clamping electrodes 201 and the top surface of the electrostatic chuck 107 is substantially free of other conductive material. As shown in FIG. 2A , the main RF power supply electrode 203 is desirably positioned below the one or more clamping electrodes 201 so that the electric field emanating from the one or more clamping electrodes 201 is not obstructed by the main RF power supply electrode 203.

[0035] In some embodiments, the region of the electrostatic chuck 107 between the main RF power supply electrode 203 and the one or more clamping electrodes 201 being substantially free of other conductive materials corresponds to the region being free of conductive materials. In some embodiments, the region of the electrostatic chuck 107 between the main RF power supply electrode 203 and the one or more clamping electrodes 201 being substantially free of other conductive materials corresponds to the region containing sparsely distributed conductive material that does not interfere with the transmission of RF signals. In some embodiments, the region of the electrostatic chuck 107 between the main RF power supply electrode 203 and the one or more clamping electrodes 201 being substantially free of other conductive materials corresponds to the region containing some conductive material that is electrically isolated from other surrounding conductive material, i.e., electrically floating. In some embodiments, the region of the electrostatic chuck 107 between the main RF power supply electrode 203 and the one or more clamping electrodes 201 is substantially free of other conductive material, which corresponds to the region including a conductive material that is thin enough not to block the RF signal.

[0036] In some embodiments, the region of the electrostatic chuck 107 between one or more clamping electrodes 201 and the top surface of the electrostatic chuck 107 being substantially free of other conductive materials corresponds to the region being free of conductive materials. In some embodiments, the region of the electrostatic chuck 107 between one or more clamping electrodes 201 and the top surface of the electrostatic chuck 107 being substantially free of other conductive materials corresponds to the region containing sparsely distributed conductive material that does not interfere with the transmission of RF signals. In some embodiments, the region of the electrostatic chuck 107 between one or more clamping electrodes 201 and the top surface of the electrostatic chuck 107 being substantially free of other conductive materials corresponds to the region containing some conductive material that is electrically isolated from other surrounding conductive material, i.e., electrically floating. In some embodiments, the region of the electrostatic chuck 107 between one or more clamping electrodes 201 and the top surface of the electrostatic chuck 107 is substantially free of other conductive material, which corresponds to the region including a conductive material that is thin enough not to block the RF signal.

[0037] In some embodiments, the main RF power supply electrode 203 is configured as an essentially solid, disk-shaped member formed of a conductive material, except for various through-holes for receiving feedthrough structures such as substrate lift pins, electrical connections for one or more clamping electrodes 201, and gas passages. In some embodiments, the main RF power supply electrode 203 is configured as graph paper formed of a conductive material. In various embodiments, the main RF power supply electrode 203 is formed of molybdenum, tantalum, tungsten, palladium, ruthenium, or platinum, among others. However, it should be understood that the main RF power supply electrode 203 can be formed of essentially any conductive material as long as it can function as a conductor for RF signals of the required frequency and meets the mechanical and thermal requirements associated with fabrication and processing. In some embodiments, the thickness of the main RF power supply electrode 203 is approximately 2-3 times the penetration depth of the RF signal transmission at the applied RF signal frequency. As an example, the penetration depth of the RF signal transmission at an applied RF frequency of 13.56 MHz is approximately 0.001778 cm. As another example, the penetration thickness for RF signal transmission at an applied RF frequency of 400 kHz is approximately 0.0016 centimeters. In some embodiments, the thickness of the main RF powered electrode 203 is within a range ranging from approximately 0.00127 centimeters to approximately 0.0381 centimeters. However, it should be understood that in other embodiments, the thickness of the main RF powered electrode 203 can be less than approximately 0.00127 centimeters or greater than approximately 0.0381 centimeters. Also, in some embodiments, the main RF powered electrode 203 is formed by applying, for example, by laminating or co-firing, a metal foil during fabrication of the electrostatic chuck 107. Also, in some embodiments, during fabrication of the electrostatic chuck 107, the main RF powered electrode 203 is formed using a screen printing process in which an ink is formulated to contain the metallic material that forms the main RF powered electrode 203. However, it should be understood that in other embodiments, different methods and techniques can be used to form the main RF powered electrode 203.

[0038] To provide electrical connection of the main RF power supply electrode 203 to the lower support structure 109, a plurality of RF power supply connection modules 209 are distributed substantially uniformly around the periphery of the electrostatic chuck 107, and each of the plurality of RF power supply connection modules 209 provides a low impedance transmission path for RF signals between the lower support structure 109 and the main RF power supply electrode 203. Each of the plurality of RF power supply connection modules 209 is configured to form an electrical connection from the lower support structure 109 (more specifically, from the upper flange 109A of the lower support structure 109) to the main RF power supply electrode 203 at its respective location, to form an RF power transmission path from the lower support structure 109 to the main RF power supply electrode 203 at its respective location.

[0039] 3A is a cross-sectional view of the electrostatic chuck 107 taken at the interface between the main RF power supply electrode 203 and the plurality of RF power supply connection modules 209, corresponding to view point A-A referenced in FIG. 2A , in accordance with some embodiments of the present invention. In the example of FIG. 3A , eight RF power supply connection modules 209 are distributed substantially evenly around the circumference of the electrostatic chuck 107 along the periphery 221, and each of the eight RF power supply connection modules 209 is separated from each adjacent one of the eight RF power supply connection modules 209 by an angle of approximately 45 degrees, as measured about the central axis 202 of the electrostatic chuck 107, which extends perpendicular to the top surface of the electrostatic chuck 107. In other embodiments, fewer than seven or more than nine RF power supply connection modules 209 can be used. For example, another example embodiment may include up to 1,000 RF power supply connection modules 209.

[0040] Also, in high frequency applications, e.g., 60 MHz or greater, it may be desirable for the main RF power supply electrode 203 to have a cross-sectional shape, such as a petal shape, for uniformity reasons. Figure 3B illustrates a modified version of the main RF power supply electrode 203 of Figure 3A, in which the main RF power supply electrode 203 is radially symmetrically interleaved about the centerline 202 of the electrostatic chuck 107, in accordance with some embodiments of the present invention. In the example embodiment of Figure 3B, gaps 309 separate each region 301-308 of the main RF power supply electrode 203 from adjacent sections of the main RF power supply electrode 203, and the regions 301-308 of the main RF power supply electrode 203 are joined near the central axis 202 of the electrostatic chuck 107. Additionally, each region 301-308 of the main RF power supply electrode 203 is connected to receive RF power from the lower support structure 109 through a respective one of a plurality of RF power supply connection modules 209A-209H.

[0041] 3C illustrates a variation of the main RF power supply electrode 203 of FIG. 3A , where the main RF power supply electrode 203 is radially symmetrically spaced about the centerline 202 of the electrostatic chuck 107, in accordance with some embodiments of the present invention. In the example embodiment of FIG. 3C , each segment 311-318 of the main RF power supply electrode 203 is separated from its adjacent segment 311-318 of the main RF power supply electrode 203. Additionally, each segment 311-318 of the main RF power supply electrode 203 is connected to receive RF power from the lower support structure 109 through a respective one of a plurality of RF power supply connection modules 209A-209H. In some embodiments, each of the plurality of RF power supply connection modules 209A-209H can be connected to receive a separately controlled RF signal such that RF signal transmission through each segment 311-318 of the main RF power supply electrode 203 can be independently controlled.

[0042] To provide uniform transmission of the RF signal from the lower support structure 109 to the main RF power supply electrode 203, the plurality of RF power supply connection modules 209 may be substantially uniformly distributed about the centerline 202 of the electrostatic chuck 107. However, the positions of the plurality of RF power supply connection modules 209 may be adjusted to accommodate their placement relative to other structures and / or passages within the electrostatic chuck 107. In some embodiments, the plurality of RF power supply connection modules 209 may be defined as passive connections that provide a direct electrical connection between the lower support structure 109 and the main RF power supply electrode 203. However, in other embodiments, some or all of the plurality of RF power supply connection modules 209 may be defined to control the amplitude and / or frequency of the RF signal transmitted from the lower support structure 109 to the main RF power supply electrode 203. Additionally, in some embodiments, individual modules of the plurality of RF power supply connection modules 209 may be configured to control the amplitude and / or frequency of the RF signal transmitted therethrough in real time.

[0043] It should be understood that the lower support structure 109, the plurality of RF power supply connection modules 209, and the main RF power supply electrode 203 collectively form a Faraday cage for directing RF power transmission around the interior space of the electrostatic chuck 107 that resides below the main RF power supply electrode 203 and within the periphery 221 along which the plurality of RF power supply connection modules 209 are disposed. FIG. 2B is a diagram illustrating the configuration of FIG. 2A with the RF signal transmission path indicated by a thick solid line 250, in accordance with some embodiments of the present invention. The RF signal is transmitted from the RF power source 129 through the matching module 131 and through the connection 127 to the lower support structure 109. The RF signal then travels near the surface of the lower support structure 109 to the upper flange 109A of the lower support structure 109. The RF signal then travels along the surface of the upper flange 109A to each of the plurality of RF power supply connection modules 209 and then to the main RF power supply electrode 203.

[0044] By transmitting the RF signal from the lower support structure 109 through the multiple RF power supply connection modules 209 to the main RF power supply electrode 203, the interior volume of the electrostatic chuck 107 is essentially free from RF signal-induced electric fields. Additionally, RF signal filtering equipment can be implemented at various locations within the electrostatic chuck 107 where the multiple RF power supply connection modules 209 and other intentional RF conductors pass through other conductive components where it is desirable not to transmit the RF signal. In this manner, the Faraday cage formed by the lower support structure 109, the multiple RF power supply connection modules 209, and the main RF power supply electrode 203, in combination with the various RF filtering equipment, serves to protect and shield the internal circuitry and connection layers of the electrostatic chuck 107 from RF fields. Furthermore, by increasing the RF signal-induced voltage within the electrostatic chuck 107 at the upper main RF power supply electrode 203, the likelihood of inadvertently igniting a plasma within the electrostatic chuck 107 is reduced. Therefore, electronic components within the interior space of the electrostatic chuck 107, such as heater circuitry, sensor circuitry, etc., may not be exposed to adverse effects caused by RF currents flowing throughout the electrostatic chuck 207 structure.

[0045] Additionally, the Faraday cage formed by the lower support structure 109, the plurality of RF power supply connection modules 209, and the main RF power supply electrode 203 provides improved consistency of RF signal transmission to the substrate 105 over a wide range of RF signal frequencies, and provides improved consistency of RF signal transmission to the substrate 105 independent of other internal circuit configurations and related variations within the electrostatic chuck 107, thereby providing improved consistency of RF signal transmission to the substrate 105 among different electrostatic chucks 107. Thus, the Faraday cage formed by the lower support structure 109, the plurality of RF power supply connection modules 209, and the main RF power supply electrode 203 provides more uniform and consistent operation of different electrostatic chucks 107 with different RF signal frequencies and harmonics.

[0046] Additionally, the location of the main RF power supply electrode 203 near the top of the electrostatic chuck 107 and immediately below the one or more clamping electrodes 201 provides for the transmission of low RF signal frequencies, such as 400 kHz, 100 kHz, 55 kHz, etc., among others. Direct connection of the main RF power supply electrode 203 to the lower support structure 109 via multiple RF power supply connection modules 209 also allows for pulsing of low RF frequency signals, which may be useful for certain plasma processing steps. Multiple RF power supply connection modules 209 configured to deliver high RF currents also enable transmission of high RF currents at low RF signal frequencies through the main RF power supply electrode 203 to the plasma processing region 119.

[0047] 4 is a longitudinal cross-sectional view of one of the plurality of RF power supply connection modules 209 according to some embodiments of the present invention. The RF power supply connection module 209 includes a first electrical connection 401 extending between the upper flange 109A of the lower support structure 109 and an exposed buried conductive segment 403 in the electrostatic chuck 107. The RF power supply connection module 209 also includes a second electrical connection 405 extending from the exposed buried conductive segment 403 through the electrostatic chuck 107 to the main RF power supply electrode 203 to provide electrical connection between the exposed buried conductive segment 403 and the main RF power supply electrode 203. In some embodiments, the exposed buried conductive segment 403 is planar. In other embodiments, the exposed buried conductive segment 403 is non-planar, such as convex, concave, cylindrical, or the like, among others. A portion 403A of the exposed buried conductive segment 403 is exposed to the bottom side of the electrostatic chuck 107 and is in physical contact with a member of the first electrical connection 401. In some embodiments, the exposed buried conductive segment 403 can be plated to allow electrical connection with the first electrical connection 401 .

[0048] The first electrical connection 401 and the second electrical connection 405 are configured to accommodate thermally induced expansion and contraction of the support / surrounding / interface structures of the electrostatic chuck 107. In some embodiments, the first electrical connection 401 includes a conductive pin 407 that presses against the exposed portion 403A of the exposed embedded conductive segment 403. In some embodiments, the first electrical connection 401 is electrically shorted to the lower support structure 109. In other embodiments, the first electrical connection 401 is electrically isolated from the lower support structure 109 but positioned such that RF signals are preferentially transmitted from the lower support structure 109 through the first electrical connection 401. In some embodiments, such as shown in FIG. 4 , the conductive pin 407 is electrically connected to the lower support structure 109 to enable transmission of RF signals from the lower support structure 109 to the conductive pin 407. Specifically, the conductive pin 407 is positioned to electrically connect to its base structure 409, which in turn is positioned to electrically connect to the lower support structure 109. In this configuration, the RF signal travels along the outer surface of the lower support structure 109, across the upper flange 109A of the lower support structure 109, to the base structure 409, to the pin 407, up the exposed buried conductive segment 403, through the second electrical connection 405, and to the main RF power supply electrode 203. In some embodiments, the conductive pin 407 includes a spring configured to press the conductive pin 407 against the exposed portion 403A of the exposed buried conductive segment 403. Also, in some embodiments, the conductive pin 407 is configured to carry an RF current of up to 30 amperes. However, it should be understood that in other embodiments, the conductive pin 407 can be configured to carry more or less RF current depending on the process being performed by the electrostatic chuck 107.

[0049] Also, in some embodiments, the connection between the lower support structure 109 and the exposed buried conductive segment 403 is made using a brazed or soldered connection instead of using the conductive pin 407. In some embodiments, regardless of whether the first electrical connection 401 uses the conductive pin 407, or a brazed connection, or a soldered connection, or some other type of connection as the RF conductor, the first electrical connection 401 is configured so that the distance that the RF conductor passes between the exposed buried conductive segment 403 and the lower support structure 109 is as short as possible to minimize the electrical impedance of the first electrical connection 401.

[0050] In some embodiments, the second electrical connection 405 includes one or more internally embedded conductive segments 411 within the ceramic of the electrostatic chuck 107. In some embodiments, the internally embedded conductive segments 411 are each oriented substantially parallel to the main RF power supply electrode 203. The second electrical connection 405 may also include one or more vertical conductive structures 413 positioned to electrically connect the internally embedded conductive segments 411 (if there is more than one internally embedded conductive segment 411) to each other, to the exposed embedded conductive segments 403, and to the main RF power supply electrode 203. In some embodiments, at least one of the vertical conductive structures 413 extends through the ceramic of the electrostatic chuck 107 between the exposed buried conductive segment 403 and the lowest one of the internal buried conductive segments 411, at least one of the vertical conductive structures 413 extends through the ceramic of the electrostatic chuck 107 between the highest one of the internal buried conductive segments 411 and the main RF power supply electrode 203, and at least one of the vertical conductive structures 413 extends through the ceramic of the electrostatic chuck 107 between every two adjacent ones of the internal buried conductive segments, when present.

[0051] It will be appreciated that the use of the internally embedded conductive segments 411 lends itself to stacked fabrication of the electrostatic chuck 107 by using vertical conductive structures 413 to connect the internally embedded conductive segments 411. It should also be understood that the vertical conductive structures 413 can be located at various positions on either side of a given internally embedded conductive segment 411. In this manner, electrical connections within the second electrical connection portion 405 of the RF power supply connection module 209 can be made at various vertical and horizontal positions. The vertical conductive structures 413 can also be located in a redundant manner within a given RF power supply connection module 209. For example, in some embodiments, in a given RF power supply connection module 209, at least four vertical conductive structures 413 extend through the ceramic of the electrostatic chuck 107 between the exposed buried conductive segment 403 and the lowest one of the internal buried conductive segments 411, at least four vertical conductive structures 413 extend through the ceramic of the electrostatic chuck 107 between the highest one of the internal buried conductive segments 411 and the main RF power supply electrode 203, and at least four vertical conductive structures 413 extend through the ceramic of the electrostatic chuck 107 between every two adjacent ones of the internal buried conductive segments 411, when present.

[0052] FIG. 5 illustrates an example of using four vertical conductive structures 413 in a redundant manner between two adjacent ones of the interior buried conductive segments 411, according to some embodiments of the present invention. It should be understood that the depiction of four vertical conductive structures 413 in the example of FIG. 5 is provided for illustrative purposes only. In other embodiments, more than four or fewer than three vertical conductive structures 413 can be disposed between two adjacent ones of the buried conductive segments 411. For example, FIG. 5 illustrates the option of having an additional vertical conductive structure 413A. In various embodiments, the number of vertical conductive structures 413 disposed between two adjacent ones of the interior buried conductive segments 411 in a given RF power supply connection module 209 can be determined by the selection of one or more materials used to fabricate the vertical conductive structures 413 and / or the interior buried conductive segments 411 and the capacitance of the selected material(s).

[0053] FIG. 6A illustrates an electrostatic chuck 107A formed of a ceramic material having a stepped configuration, according to some embodiments of the present invention. FIG. 6B illustrates a top view of the electrostatic chuck 107A, according to some embodiments of the present invention. The electrostatic chuck 107A includes a central region 601 and a peripheral region 603. The central region 601 includes an area configured to support a substrate 105. The peripheral region 603 is configured to surround the central region 601. The electrostatic chuck 107A has a bottom surface that extends substantially uniformly and planarly across both the central region 601 and the peripheral region 603. The central region 601 has a first overall thickness 605 measured perpendicular to the bottom surface of the electrostatic chuck 107A. The peripheral region 603 has a second overall thickness 607 measured perpendicular to the bottom surface of the electrostatic chuck 107A. The second overall thickness 607 is less than the first overall thickness 605, which provides the electrostatic chuck 107A with a stepped configuration at its radially outer periphery. The main RF power supply electrode 203 is positioned entirely within the central region 601 of the electrostatic chuck 107A at a position immediately below the one or more clamping electrodes 201. The peripheral region 603 of the electrostatic chuck 107A includes a portion of a peripheral RF power supply electrode 609. The peripheral RF power supply electrode 609 also extends below an outer portion of the main RF power supply electrode 203 into the central region 601 of the electrostatic chuck 107A.

[0054] The peripheral RF power supply electrode 609 is formed in the electrostatic chuck 107A at a vertical position below the main RF power supply electrode 203. The peripheral RF power supply electrode 609 has an annular shape defined by a top surface, a bottom surface, an inner edge 609A, and an outer edge 609B. In some embodiments, the top and bottom surfaces of the peripheral RF power supply electrode 609 are oriented substantially parallel to the main RF power supply electrode 203. The inner edge 609A of the peripheral RF power supply electrode 609 is positioned radially closer to the centerline 202 of the electrostatic chuck 107A than the outer edge 203A of the main RF power supply electrode 203 such that an overlap 613 exists between the main RF power supply electrode 203 and the peripheral RF power supply electrode 609. Again, the centerline 202 of the electrostatic chuck 107A is considered to extend perpendicular to the top surface of the electrostatic chuck 107A at the center point of the top surface of the electrostatic chuck 107A. The outer edge 609B of the peripheral RF powered electrode 609 is positioned radially farther from the centerline 202 of the electrostatic chuck 107A than the outer edge 203A of the main RF powered electrode 601. The radial extension of the peripheral RF powered electrode 609 outward from the main RF powered electrode 601 enables transmission of RF signals throughout the radial periphery of the substrate 105, which in some processing applications can be used to improve processing performance at the radial edge of the substrate 105. The peripheral RF powered electrode 209 extends RF coupling to the plasma outward from the radial periphery of the substrate 105, enabling improved processing performance at the outermost regions and edges of the substrate 105.

[0055] To provide electrical connection of the peripheral RF power supply electrode 609 and the main RF power supply electrode 203 to the lower support structure 109, a plurality of RF power supply connection modules 629 are distributed substantially uniformly around the periphery of the electrostatic chuck 107A, each providing a low impedance transmission path for RF signals between the lower support structure 109 and the peripheral RF power supply electrode 609 and the main RF power supply electrode 203. The plurality of RF power supply connection modules 629 may be distributed around the periphery of the electrostatic chuck 107A in a manner similar to that discussed herein with respect to the distribution of the plurality of RF power supply connection modules around the periphery of the electrostatic chuck 107A.

[0056] 6C is a longitudinal cross-sectional view of one of a plurality of RF power supply connection modules 629, according to some embodiments of the present invention. In some embodiments, the RF power supply connection modules 629 each include a first electrical connection 401 extending between the lower support structure 109 and an exposed buried conductive segment 403 in the electrostatic chuck 107A, with a portion 403A of the exposed buried conductive segment 403 exposed on the bottom side of the electrostatic chuck 107A. As described above with respect to FIG. 4 , the first electrical connection 401 can be formed by a conductive pin 407 in some embodiments. Alternatively, in other embodiments, the first electrical connection 401 can be formed by a brazed or soldered connection extending between the lower support structure 109 and the exposed buried conductive segment 403.

[0057] Each RF power supply connection module 629 also includes a second electrical connection 621 extending from the exposed buried conductive segment 403 through the electrostatic chuck 107A to the main RF power supply electrode 203. The second electrical connections 621 include a lower electrical connection 623 extending from the exposed buried conductive segment 403 through the electrostatic chuck 107A to the peripheral RF power supply electrode 609. The second electrical connections 621 also include an upper electrical connection 625 extending from the peripheral RF power supply electrode 609 through the electrostatic chuck 107A to the main RF power supply electrode 203. The lower electrical connections 623 can be formed using several interior buried conductive segments 411 and vertical conductive structures 413, similar to the manner discussed with respect to the second electrical connections 405 of FIG. 4 . In the example of Figure 6C, one of the interior buried conductive segments 411 and two vertical conductive structures 413 are used to form the lower electrical connection 623 extending from the exposed buried conductive segment 403 to the peripheral RF power supply electrode 609. Similarly, the upper electrical connection 625 can be formed using several interior buried conductive segments 411 and vertical conductive structures 413, similar to the manner discussed with respect to the second electrical connection 405 of Figure 4. In the example of Figure 6C, three interior buried conductive segments 411 and four vertical conductive structures 413 are used to form the upper electrical connection 625 extending from the peripheral RF power supply electrode 609 to the main RF power supply electrode 203.

[0058] 6C , the RF signal is transmitted to the main RF power supply electrode 203 through the peripheral RF power supply electrode 609. However, in other embodiments, the RF signal can be transmitted first to the main RF power supply electrode 203 and then through the main RF power supply electrode 203 to the peripheral RF power supply electrode 609. Also, in some embodiments, the RF signal can be transmitted from the lower support structure 109 to the peripheral RF power supply electrode 609 without first passing through the main RF power supply electrode 203, and the RF signal can be transmitted from the lower support structure 109 to the main RF power supply electrode 203 without first passing through the peripheral RF power supply electrode 609.

[0059] Additionally, in some embodiments, the peripheral RF powered electrode 609 can be electrically isolated from the main RF powered electrode 203 by a portion of the electrostatic chuck 107A ceramic acting as an insulator between them. In these embodiments, the peripheral RF powered electrode 609 and the main RF powered electrode 203 can each be independently connected to receive RF signals directly from the lower support structure 109. Also, in this configuration, in some embodiments, the RF signal transmission paths to each of the peripheral RF powered electrode 609 and the main RF powered electrode 203 can be independently controlled to allow for independent control of the RF current delivered to the periphery of the electrostatic chuck 107A relative to the RF current delivered to the substrate 105 supporting central region 601 of the electrostatic chuck 107A. Thus, in various embodiments, having both the peripheral RF powered electrode 609 and the main RF powered electrode 203 allows for the application of additional RF signal frequencies at the peripheral RF powered electrode 609 but not at the main RF powered electrode 203, and allows for the application of additional RF signal frequencies at the main RF powered electrode 203 but not at the peripheral RF powered electrode 609, thereby providing increased operational flexibility in processing the edge of the substrate 105.

[0060] 6D is a longitudinal cross-sectional view of one of a plurality of RF power supply connection modules 629 according to some embodiments of the present invention, in which the first electrical connection 401 is electrically isolated from the lower support structure 109 so that independently controlled RF signals can be transmitted to each of the plurality of RF power supply connection modules 629 and the lower support structure 109. In the example of FIG. 6D , the base structure 409 of the conductive pin 407 is disposed within an electrically insulating member 410, such as a dielectric sleeve, so that it is electrically isolated from the lower support structure 109. The base structure 409 of the conductive pin 407 is connected to an RF power source 412 by an appropriate impedance matching circuit arrangement. In this configuration, the RF signal generated by the RF power source 412 travels to the base structure 409, from the base structure 409 to the conductive pin 407, and from the conductive pin 407 to the exposed buried conductive segment 403, rather than traveling through the lower support structure 109. In some embodiments, the RF power source 412 is connected to the RF control module 165 such that the RF signal transmitted from the RF power source 412 to the base structure 409 of the conductive pin 407 is controlled by the RF control module 165.

[0061] 1 , the system may also include a first voltage sensor 161 connected to measure the voltage (V1) across the main RF powered electrode 203 and a second voltage sensor 163 connected to measure the voltage (V2) across one or more clamp electrodes 201. The first voltage sensor 161 and the second voltage sensor 163 are defined and located separately from the connections used to transmit RF signals from the lower support structure 109 to the main RF powered electrode 203. The first voltage sensor 161 and the second voltage sensor 163 are each connected to transmit signals indicative of their respective measured voltages V1 and V2 to an RF control module 165. The RF control module 165 is configured to determine an amount of RF current transmission from the main RF power supply electrode 203 through the top surface of the electrostatic chuck 107 using the measured voltage V1 across the main RF power supply electrode 203, the measured voltage V2 across the one or more clamping electrodes 201, and the capacitance C between the main RF power supply electrode 203 and the one or more clamping electrodes 201. In some embodiments, the RF control module 165 is further configured to transmit a control signal to the RF power source 129 through the connection 166 to control the RF power source 129 in a closed-loop feedback manner to send a predetermined amount of RF current through the top surface of the electrostatic chuck 107 based on the determined amount of RF current transmission from the main RF power supply electrode 203 through the top surface of the electrostatic chuck 107. In some embodiments, the RF control module 165 is further configured to transmit a control signal to the RF power source 129 through the connection 166 to control the RF power source 129 in a closed-loop feedback manner to control the voltage present on the substrate 105. In some embodiments, the RF control module 165 is further configured to transmit a control signal to the RF power source 129 via connection 166 to control the RF power source 129 in a closed-loop feedback manner to control the amount of RF power transmitted through the top surface of the electrostatic chuck 107 in a phase-sensitive manner.

[0062] The capacitance (C) between the main RF powered electrode 203 and the one or more clamping electrodes 201 can be measured or calculated based on the dielectric constant of the ceramic material of the electrostatic chuck 107 and the geometry of the main RF powered electrode 203 and the one or more clamping electrodes 201. Once the capacitance (C) between the main RF powered electrode 203 and the one or more clamping electrodes 201 is determined, the reciprocal of that quantity (2×π×f×C), i.e., X C = 1 / (2πfC), the reactance (X) of the ceramic material of the electrostatic chuck 107 between the main RF power supply electrode 203 and the one or more clamping electrodes 201. C ) can be determined, where frequency f is in Hz and capacitance C is in Farads. The measured voltage difference (|V1-V2|) between the main RF powered electrode 203 and the one or more clamping electrodes 201 can then be multiplied by the determined reactance (X C ), the real-time RF current (I) being transmitted from the main RF power supply electrode 203 to the one or more clamping electrodes 201 can be determined. The real-time RF current (I) represents the RF current flowing through the substrate 105 and out into the plasma processing region 119. It can also be seen that because the real-time RF current (I) is based on the measured voltages across the main RF power supply electrode 203 and the one or more clamping electrodes 201, it is not distorted by parasitic RF currents flowing along structures peripheral to the electrostatic chuck 107 within the plasma processing chamber 101. Any small amount of residual parasitic current loss can also be counteracted through calibration and compensation.

[0063] Conversely, the RF current measured downstream near the reference ground potential 125 includes RF current flowing through the plasma processing region 119 and parasitic RF current flowing along peripheral structures within the chamber 101. Also, in the case of a low-density plasma 133, the parasitic RF current dominates the RF current measured downstream near the reference ground potential 125. Therefore, measuring the RF current downstream near the reference ground potential 125 may not reliably measure only the RF current flowing through the plasma processing region 119, especially in the case of a low-density plasma 133 process. However, the above-described method for determining the amount of RF current transmission from the main RF power supply electrode 203, through the top surface of the electrostatic chuck 107, and into the plasma processing region 119 using the measured voltage V1 across the main RF power supply electrode 203, the measured voltage V2 across the one or more clamping electrodes 201, and the capacitance C between the main RF power supply electrode 203 and the one or more clamping electrodes 201 can be used instead of measuring the RF current downstream near the reference ground potential 125.

[0064] 7 is a flowchart illustrating a method for determining RF current delivery in a plasma processing process, according to some embodiments of the present invention. The method includes operation 701 for delivering RF power to a main RF power supply electrode (203) within an electrostatic chuck (107 / 107A). The main RF power supply electrode (203) is positioned within the ceramic of the electrostatic chuck (107 / 107A) in an orientation substantially parallel to an upper surface of the electrostatic chuck (107 / 107A). The upper surface of the electrostatic chuck (107 / 107A) includes an area configured to support a substrate (105). The main RF power supply electrode (203) is positioned within the electrostatic chuck (107 / 107A) at a position vertically below one or more clamping electrodes (201) such that a region of the electrostatic chuck (107 / 107A) between the main RF power supply electrode (203) and the one or more clamping electrodes (201) is substantially free of other conductive materials. The main RF power supply electrode (203) and one or more clamping electrodes (201) are each configured to extend horizontally within the electrostatic chuck (107 / 107A) to cover at least the entire area of the top surface of the electrostatic chuck (107 / 107A) below the area configured to support the substrate (105). Operation 701 for transmitting RF power to the main RF power supply electrode (203) within the electrostatic chuck (107 / 107A) may include transmitting an RF signal to the lower support structure (109) of the electrostatic chuck (107 / 107A) such that the RF signal travels from the lower support structure (109) to a plurality of RF power supply connection modules (209 / 629) distributed substantially uniformly around the electrostatic chuck (107 / 107A), and such that the RF signal travels to the main RF power supply electrode (203) through each of the plurality of RF power supply connection modules (209 / 629) at the location of each of the plurality of RF power supply connection modules (209 / 629).

[0065] The method also includes operation 703 for determining a capacitance (C) between the main RF power supply electrode (203) and the one or more clamping electrodes (201). The method also includes operation 705 for measuring a voltage (V1) across the main RF power supply electrode (203). The method also includes operation 707 for measuring a voltage (V2) across the one or more clamping electrodes (201). The method also includes operation 709 for determining an amount of RF current (I) transmission from the main RF power supply electrode (203) through the top surface of the electrostatic chuck (107 / 107A) using the determined capacitance (C) between the main RF power supply electrode (203) and the one or more clamping electrodes (201), the measured voltage (V1) across the main RF power supply electrode (203), and the measured voltage (V2) across the one or more clamping electrodes (201). Operation 709 for determining the amount of RF current (I) transmission from the main RF power supply electrode (203) through the top surface of the electrostatic chuck (107 / 107A) includes multiplying the difference between the measured voltage (V1) across the main RF power supply electrode (203) and the measured voltage (V2) across the one or more clamping electrodes (201) by the determined capacitance (C) between the main RF power supply electrode (203) and the one or more clamping electrodes (201).

[0066] By incorporating voltage monitoring circuitry, such as that associated with a first voltage sensor 161 connected to measure the voltage (V1) across the main RF power supply electrode 203 and a second voltage sensor 163 connected to measure the voltage (V2) across one or more clamp electrodes 201, within the electrostatic chuck 107 / 107A near the substrate 105, or by incorporating at least pickup electrodes and connections for that purpose internal to the electrostatic chuck 107 / 107A structure, more accurate point-of-use broadband measurements of the RF current transmitted from the electrostatic chuck 107 / 107A to the plasma processing region 119 can be obtained. Point-of-use broadband measurements of the RF current flowing into the plasma processing region 119 can be used for diagnostic, monitoring, and / or control purposes. For example, point-of-use broadband measurements of the RF current flowing into the plasma processing region 119 can be processed through external circuitry, such as within the RF control module 165, to implement control strategies, such as real-time closed-loop feedback control of the RF current transmitted into the plasma processing region 119. Also, with sufficiently accurate resolution of the phase of the RF voltage and RF current at the point of use, i.e., near the substrate 105 support area, the delivered broadband RF power at the point of use can be determined and optionally used for control purposes.

[0067] By measuring the voltage difference between at least two locations within the electrostatic chuck 107 / 107A (e.g., a location on the main RF power supply electrode 203 near the substrate 105 support location and a location on one or more clamping electrodes 201) and knowing the impedance (reactance) between these at least two locations, it is possible to determine the RF current flowing between these at least two locations without implementing specialized current measurement hardware. And, because the voltage measurement is made at an elevated location within the electrostatic chuck 107 / 107A near the substrate 105 support location, it is relatively immune to parasitic RF currents flowing in parallel stray capacitances presented by peripheral support structures, such as the parallel stray capacitance presented by the peripheral ceramic insulating ring, among others. The voltage measurement's relative immunity to these parasitic RF currents provides a significant advantage in that a point-of-use broadband measurement of the RF current transmitted from the electrostatic chuck 107 / 107A to the plasma processing region 119 represents substantially only the RF current flowing to and through the substrate 105. Then, by knowing the RF current flowing through the substrate 105 from the electrostatic chuck 107 / 107A to the plasma processing region 119, and by knowing the capacitance of the substrate 105, it is possible to determine the voltage across the substrate 105. And, as previously described, the RF control module 165 is operable to transmit control signals to the RF power source 129 over connection 166 to control the RF power source 129 in a closed-loop feedback manner to control one or more of the voltage across the substrate 105, the RF current transmitted through the substrate 105, and the RF power transmitted through the substrate 105.

[0068] 8 is a flowchart illustrating a method for manufacturing an electrostatic chuck (107 / 107A) according to some embodiments of the present invention. The method includes operation 801 for forming a ceramic assembly for the electrostatic chuck (107 / 107A) having an upper surface including an area configured to support a substrate (105). Operation 801 includes positioning one or more clamping electrodes (201) within the ceramic assembly in an orientation substantially parallel to and above the upper surface of the ceramic assembly, such that a region of the ceramic assembly between the one or more clamping electrodes (201) and the upper surface of the ceramic assembly is substantially free of other conductive materials. Operation 801 also includes positioning a main RF power supply electrode (203) within the ceramic assembly in an orientation substantially parallel to and vertically below the one or more clamping electrodes (201), such that a region of the ceramic assembly between the main RF power supply electrode (203) and the one or more clamping electrodes (201) is substantially free of other conductive materials. The main RF power supply electrode (203) is configured to extend horizontally within the ceramic assembly to span at least the entire area of an upper surface of the ceramic assembly below an area configured to support a substrate (105). Operation 801 includes positioning a plurality of RF power supply connection modules (209 / 629) to be substantially uniformly distributed around the periphery of the ceramic assembly. Each of the plurality of RF power supply connection modules (209 / 629) is configured to form an electrical connection from the lower support structure (109) to the main RF power supply electrode (203) at its respective location to form an RF power transmission path from the lower support structure (109) to the main RF power supply electrode (203) at its respective location.

[0069] The method also includes operation 803 for attaching the ceramic assembly to a lower support structure (109). The lower support structure (109) is formed of a conductive material. The lower support structure (109) has a bowl shape formed by a bottom member (109B) and an annular wall member (109C) extending upward from the bottom member (109B). The ceramic assembly is attached to the lower support structure (109) such that an outer periphery of the bottom surface of the ceramic assembly is supported by an upper surface of the annular wall member (109C) of the lower support structure (109) and an interior region of the lower support structure (109) is exposed to a portion of the bottom surface of the ceramic assembly.

[0070] As discussed herein, the lower support structure 109, the plurality of RF power supply connection modules 209 / 629, and the main RF power supply electrode 203 collectively form a Faraday cage for directing RF power transmission around the interior space of the electrostatic chuck 107 that exists between the bottom surface of the electrostatic chuck 107 / 107A and the main RF power supply electrode 203, and within the periphery of the electrostatic chuck 107 / 107A along which the plurality of RF power supply connection modules 209 / 629 are disposed. This Faraday cage serves to conduct RF current around the interior region of the electrostatic chuck 107 / 107A, thereby protecting the internal components and circuitry within the interior region of the electrostatic chuck 107 / 107A from RF-induced damage. The Faraday cage configuration also serves to uniformly distribute the RF signal to the region above the electrostatic chuck 107 / 107A, which results in a more uniform plasma density across the substrate 105. Additionally, in the Faraday cage configuration, the main RF power supply electrode 203 is located near the top surface of the electrostatic chuck 107 / 107A, so that a low frequency RF signal, such as 2 MHz down to 400 kHz or less, can be reliably delivered to the plasma processing region 119. Additionally, because the low frequency RF signal is transmitted around the interior region of the electrostatic chuck 107 / 107A, the likelihood of parasitic discharge within the interior region of the electrostatic chuck 107 / 107A is significantly reduced.

[0071] Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be made within the scope of the appended claims. Accordingly, these embodiments are to be considered as illustrative and not restrictive, and the invention is not limited to the details given herein, but may be modified within the scope and equivalents of the described embodiments. The present disclosure may be realized in the following forms. [Form 1] An electrostatic chuck, a ceramic assembly having a top surface including an area configured to support a substrate; at least one clamp electrode positioned within the ceramic assembly in an orientation substantially parallel to the top surface of the ceramic assembly and at an upper position within the ceramic assembly such that a region of the ceramic assembly between the at least one clamp electrode and the top surface of the ceramic assembly is substantially free of other conductive material; a main radio frequency (RF) power supply electrode positioned within the ceramic assembly in an orientation substantially parallel to the top surface of the ceramic assembly and vertically below the at least one clamping electrode such that a region of the ceramic assembly between the main RF power supply electrode and the at least one clamping electrode is substantially free of other conductive material, the main RF power supply electrode configured to extend horizontally within the ceramic assembly to at least extend below the area of the top surface of the ceramic assembly configured to support the substrate; a lower support structure formed of a conductive material, the lower support structure having a bowl shape formed by a bottom member and an annular wall member extending upward from the bottom member, the ceramic assembly being secured to the lower support structure such that an outer circumferential region of the bottom surface of the ceramic assembly is supported by an upper surface of the annular wall member of the lower support structure and an interior region of the lower support structure is exposed to a portion of the bottom surface of the ceramic assembly; a plurality of RF power supply connection modules substantially uniformly distributed around the periphery of the ceramic assembly, each RF power supply connection module configured to form an electrical connection from the lower support structure to the main RF power supply electrode at a respective location to form an RF power transmission path from the lower support structure to the main RF power supply electrode at a respective location; Equipped with The electrostatic chuck, wherein the lower support structure, the plurality of RF power supply connection modules, and the main RF power supply electrode collectively form a Faraday cage for directing RF power transmission around an interior region of the electrostatic chuck. [Form 2] 2. The electrostatic chuck according to claim 1, each of the plurality of RF power supply connection modules includes a first electrical connection extending between the lower support structure and an exposed embedded conductive segment within the ceramic assembly; the exposed buried conductive segment has an exposed portion exposed on a bottom side of the ceramic assembly; the plurality of RF power supply connection modules each including a second electrical connection from the exposed buried conductive segment through the ceramic assembly to the main RF power supply electrode. [Form 3] 3. The electrostatic chuck according to claim 2, the first electrical connection includes a conductive pin pressed against the exposed portion of the exposed buried conductive segment; The conductive pin is electrically connected to the lower support structure to enable transmission of an RF signal from the lower support structure to the conductive pin. [Form 4] 4. The electrostatic chuck according to claim 3, The electrostatic chuck, wherein the conductive pin is configured to carry a current of up to 30 amperes. [Form 5] 3. The electrostatic chuck according to claim 2, the second electrical connection includes one or more internally embedded conductive segments within the ceramic assembly; the one or more internally embedded conductive segments are each oriented substantially parallel to the main RF powered electrode; the second electrical connection portion includes one or more vertical conductive structures positioned to electrically connect the one or more interior buried conductive segments to each other, to the exposed buried conductive segments, and to the main RF power supply electrode. [Form 6] 6. An electrostatic chuck according to claim 5, at least one of the vertical conductive structures extends through the ceramic assembly between the exposed buried conductive segment and a lowermost one of the internal buried conductive segments; at least one of the vertical conductive structures extends through the ceramic assembly between an uppermost one of the interior buried conductive segments and the main RF power delivery electrode; an electrostatic chuck, wherein at least one of the vertical conductive structures extends through the ceramic assembly between adjacent two of the internally embedded conductive segments, when present; [Form 7] 6. An electrostatic chuck according to claim 5, at least four of the vertical conductive structures extend through the ceramic assembly between the exposed buried conductive segment and a lowermost one of the internal buried conductive segments; at least four of the vertical conductive structures extend through the ceramic assembly between an uppermost one of the interior buried conductive segments and the main RF power delivery electrode; at least four of the vertical conductive structures extend through the ceramic assembly between adjacent two of the interior-embedded conductive segments, when present. [Form 8] 3. The electrostatic chuck according to claim 2, the plurality of RF power supply connection modules includes eight RF power supply connection modules positioned near a periphery of the ceramic assembly; wherein each of the eight RF power supply connection modules is spaced apart from adjacent ones of the eight RF power supply connection modules by an angle of approximately 45 degrees when measured about a central axis of the ceramic assembly that extends perpendicular to the top surface of the ceramic assembly. [Form 9] 2. The electrostatic chuck according to claim 1, The electrostatic chuck, wherein the main RF powered electrode is formed as a disk-shaped member. [Form 10] 2. The electrostatic chuck according to claim 1, the main RF powered electrodes are spaced radially symmetrically about a central axis of the ceramic assembly that extends perpendicular to the top surface of the ceramic assembly; each segment of the main RF powered electrode is spaced apart from an adjacent segment of the main RF powered electrode; An electrostatic chuck wherein each section of the main RF power supply electrode is connected to receive RF power from a respective one of the plurality of RF power supply connection modules. [Form 11] The electrostatic chuck according to aspect 1, further comprising: a peripheral RF powered electrode formed within the ceramic assembly at a vertical location within the ceramic assembly below the main RF powered electrode, the peripheral RF powered electrode having an annular shape defined by a top surface, a bottom surface, an inner edge, and an outer edge; the top and bottom surfaces of the peripheral RF powered electrode are oriented substantially parallel to the main RF powered electrode; the inner edge of the peripheral RF powered electrode is positioned radially closer to a centerline of the ceramic assembly than the outer edge of the main RF powered electrode; the centerline of the ceramic assembly extends perpendicular to the top surface of the ceramic assembly; 1. An electrostatic chuck comprising: a peripheral RF powered electrode, wherein the outer edge of the peripheral RF powered electrode is positioned radially farther from the centerline of the ceramic assembly than the outer edge of the main RF powered electrode. [Form 12] 12. The electrostatic chuck according to claim 11, each of the plurality of RF power supply connection modules includes a first electrical connection extending between the lower support structure and an exposed embedded conductive segment within the ceramic assembly; a portion of the exposed buried conductive segment exposed on a bottom side of the ceramic assembly; each of the plurality of RF power supply connection modules includes a second electrical connection from the exposed buried conductive segment through the ceramic assembly to the main RF power supply electrode; the second electrical connection includes a lower electrical connection extending through the ceramic assembly from the exposed buried conductive segment to the peripheral RF power supply electrode, and an upper electrical connection extending through the ceramic assembly from the peripheral RF power supply electrode to the main RF power supply electrode. [Form 13] 13. The electrostatic chuck according to claim 12, the ceramic assembly includes a central region and a peripheral region; the central region includes an area configured to support the substrate; the peripheral region is configured to surround the central region; the ceramic assembly has a bottom surface that extends substantially uniformly in a planar manner across both the central region and the peripheral region; the central region has a first overall thickness measured perpendicular to the bottom surface of the ceramic assembly; the peripheral region has a second overall thickness measured perpendicular to the bottom surface of the ceramic assembly; the second overall thickness is less than the first overall thickness; the main RF powered electrode is positioned entirely within the central region; The electrostatic chuck, wherein the peripheral region includes a portion of the peripheral RF powered electrode. [Form 14] 2. The electrostatic chuck according to claim 1, The region of the ceramic assembly between the at least one clamping electrode and the upper surface of the ceramic assembly is substantially free of other conductive materials. the region of the ceramic assembly between the at least one clamp electrode and the top surface of the ceramic assembly is free of conductive material; or the region of the ceramic assembly between the at least one clamp electrode and the top surface of the ceramic assembly includes sparsely distributed conductive material that does not interfere with the transmission of RF signals; or the region of the ceramic assembly between the at least one clamp electrode and the top surface of the ceramic assembly includes some conductive material that is electrically insulated from other surrounding conductive material; or the region of the ceramic assembly between the at least one clamp electrode and the top surface of the ceramic assembly includes a conductive material that is thin enough not to block RF signals; The region of the ceramic assembly between the main RF powered electrode and the at least one clamp electrode is substantially free of other conductive materials. the region of the ceramic assembly between the main RF powered electrode and the at least one clamp electrode is free of conductive material; or the region of the ceramic assembly between the main RF powered electrode and the at least one clamp electrode includes sparsely distributed conductive material that does not impede RF signal transmission; or the region of the ceramic assembly between the main RF powered electrode and the at least one clamp electrode comprises some conductive material that is electrically insulated from other surrounding conductive material; or an electrostatic chuck, wherein the region of the ceramic assembly between the main RF power supply electrode and the at least one clamp electrode includes a conductive material that is sufficiently thin so as not to block an RF signal. [Form 15] 2. The electrostatic chuck according to claim 1, the lower support structure includes an upper flange structure; an upper surface of the annular wall member of the lower support structure that is coplanar with an upper surface of the upper flange structure; [Form 16] 16. An electrostatic chuck according to claim 15, The electrostatic chuck, wherein the plurality of RF power supply connection modules are each configured to physically contact the upper flange structure of the lower support structure. [Form 17] 1. A system for plasma processing, comprising: a processing chamber; an electrostatic chuck positioned within the processing chamber, a ceramic assembly having a top surface including an area configured to support a substrate; at least one clamp electrode positioned within the ceramic assembly in an orientation substantially parallel to the top surface of the ceramic assembly and at an upper position within the ceramic assembly such that a region of the ceramic assembly between the at least one clamp electrode and the top surface of the ceramic assembly is substantially free of other conductive material; a main radio frequency (RF) power supply electrode positioned within the ceramic assembly in an orientation substantially parallel to the top surface of the ceramic assembly and vertically below the at least one clamping electrode such that a region of the ceramic assembly between the main RF power supply electrode and the at least one clamping electrode is substantially free of other conductive material, the main RF power supply electrode configured to extend horizontally within the ceramic assembly to at least extend below the area of the top surface of the ceramic assembly configured to support the substrate; a lower support structure formed of a conductive material, the lower support structure having a bowl shape formed by a bottom member and an annular wall member extending upward from the bottom member, the ceramic assembly being secured to the lower support structure such that an outer circumferential region of the bottom surface of the ceramic assembly is supported by an upper surface of the annular wall member of the lower support structure and an interior region of the lower support structure is exposed to a portion of the bottom surface of the ceramic assembly; a plurality of RF power supply connection modules substantially uniformly distributed around the periphery of the ceramic assembly, each RF power supply connection module configured to form an electrical connection from the lower support structure to the main RF power supply electrode at a respective location to form an RF power transmission path from the lower support structure to the main RF power supply electrode at a respective location; an electrostatic chuck including: an RF power source connected to transmit RF power to the lower support structure of the electrostatic chuck; Equipped with 10. A system for plasma processing, wherein the lower support structure, the plurality of RF power supply connection modules, and the main RF power supply electrode collectively form a Faraday cage for directing RF power transmission around an interior region of the electrostatic chuck. [Form 18] 18. The system for plasma processing according to claim 17, further comprising: a first voltage sensor connected to measure a voltage across the main RF powered electrode; a second voltage sensor connected to measure a voltage across the at least one clamping electrode; an RF control module configured to determine an amount of RF current transmission from the main RF power supply electrode through the top surface of the ceramic assembly of the electrostatic chuck using the measured voltage across the main RF power supply electrode, the measured voltage across the at least one clamping electrode, and a capacitance between the main RF power supply electrode and the at least one clamping electrode; A system for plasma processing comprising: [Form 19] 18. A system for plasma processing according to claim 17, comprising: the RF control module is further configured to control the RF power source based on the determined amount of RF current transmission from the main RF power supply electrode through the top surface of the ceramic assembly of the electrostatic chuck to send a predetermined amount of RF current through the top surface of the ceramic assembly of the electrostatic chuck. [Form 20] 1. A method for manufacturing an electrostatic chuck, comprising: forming a ceramic assembly having an upper surface including an area configured to support a substrate; forming the ceramic assembly includes positioning at least one clamping electrode within the ceramic assembly in an orientation substantially parallel to a top surface of the ceramic assembly and at an upper position within the ceramic assembly such that a region of the ceramic assembly between the at least one clamping electrode and a top surface of the ceramic assembly is substantially free of other conductive material; forming the ceramic assembly includes positioning a main radio frequency (RF) powered electrode within the ceramic assembly in an orientation substantially parallel to the top surface of the ceramic assembly and vertically below the at least one clamping electrode such that a region of the ceramic assembly between the main RF powered electrode and the at least one clamping electrode is substantially free of other conductive material, the main RF powered electrode being configured to extend horizontally within the ceramic assembly to at least extend below the area of the top surface of the ceramic assembly configured to support the substrate; forming the ceramic assembly includes positioning a plurality of RF power supply connection modules substantially uniformly distributed around the periphery of the ceramic assembly; the plurality of RF power supply connection modules are each configured to form an electrical connection from the lower support structure to the main RF power supply electrode at a respective location to form an RF power transmission path from the lower support structure to the main RF power supply electrode at a respective location; the ceramic assembly is attached to the lower support structure, the lower support structure being formed of a conductive material and having a bowl shape formed by a bottom member and an annular wall member extending upward from the bottom member, the ceramic assembly being attached to the lower support structure such that an outer circumferential region of the bottom surface of the ceramic assembly is supported by an upper surface of the annular wall member of the lower support structure and an interior region of the lower support structure is exposed to a portion of the bottom surface of the ceramic assembly; Prepared for this, the lower support structure, the plurality of RF power supply connection modules, and the main RF power supply electrode collectively form a Faraday cage for directing RF power transmission around an interior region of the electrostatic chuck.

Claims

1. 1. A substrate support system comprising: a ceramic assembly having a top surface and a bottom surface, the top surface including an area configured to support a substrate; at least one clamp electrode positioned within the ceramic assembly; a main radio frequency (RF) power supply electrode positioned within the ceramic assembly at a position vertically below the at least one clamp electrode; a peripheral RF powered electrode having an annular shape positioned within the ceramic assembly at a position vertically below the main RF powered electrode, the outer edge of the peripheral RF powered electrode being positioned farther from a centerline of the ceramic assembly than the outer edge of the main RF powered electrode; a lower support structure formed of a conductive material, the ceramic assembly being secured to the lower support structure such that a peripheral edge region of the bottom surface of the ceramic assembly is supported by the lower support structure, the lower support structure including a hollow interior region exposed to a portion of the bottom surface of the ceramic assembly; a plurality of electrical connections established between the lower support structure and the main RF power supply electrode, each of the plurality of electrical connections extending through a respective portion of the ceramic assembly, each of the plurality of electrical connections including a corresponding exposed buried conductive structure accessible from the bottom surface of the ceramic assembly, each of the plurality of electrical connections including a corresponding conductive pin in physical contact with the corresponding exposed buried conductive structure and electrically connecting with the lower support structure, each of the plurality of electrical connections including a corresponding lower electrical connection extending from the corresponding exposed buried conductive structure to the peripheral RF power supply electrode, and each of the plurality of electrical connections including a corresponding upper electrical connection extending from the peripheral RF power supply electrode to the main RF power supply electrode; A substrate support system comprising:

2. 10. The substrate support system of claim 1, The substrate support system, wherein the plurality of electrical connections are distributed within a peripheral region of the ceramic assembly.

3. 10. The substrate support system of claim 1, A substrate support system wherein the plurality of electrical connections are positioned at substantially equal intervals when measured azimuthally about a centerline of the ceramic assembly that extends perpendicular to the top surface of the ceramic assembly.

4. 10. The substrate support system of claim 1, The corresponding conductive pin includes a spring configured to urge the corresponding conductive pin against the corresponding exposed embedded conductive structure.

5. A substrate support system comprising: a ceramic assembly having a top surface and a bottom surface, the top surface including an area configured to support a substrate; at least one clamp electrode positioned within the ceramic assembly; a main radio frequency (RF) power supply electrode positioned within the ceramic assembly at a position vertically below the at least one clamp electrode; a peripheral RF powered electrode having an annular shape positioned within the ceramic assembly at a position vertically below the main RF powered electrode, the outer edge of the peripheral RF powered electrode being positioned farther from a centerline of the ceramic assembly than the outer edge of the main RF powered electrode; a lower support structure formed of a conductive material, the ceramic assembly being secured to the lower support structure such that a peripheral edge region of the bottom surface of the ceramic assembly is supported by the lower support structure, the lower support structure including a hollow interior region exposed to a portion of the bottom surface of the ceramic assembly; a plurality of electrical connections established between the lower support structure and the main RF power supply electrode, each of the plurality of electrical connections extending through a respective portion of the ceramic assembly, each of the plurality of electrical connections including a corresponding exposed buried conductive structure accessible from the bottom surface of the ceramic assembly, each of the plurality of electrical connections including a brazed or soldered connection between the corresponding exposed buried conductive structure and the lower support structure, each of the plurality of electrical connections including a corresponding lower electrical connection extending from the corresponding exposed buried conductive structure to the peripheral RF power supply electrode, and each of the plurality of electrical connections including a corresponding upper electrical connection extending from the peripheral RF power supply electrode to the main RF power supply electrode; A substrate support system comprising:

6. 10. The substrate support system of claim 1, a first vertical conductive structure electrically connecting the exposed conductive structure to the corresponding buried conductive segment, and a second vertical conductive structure electrically connecting the exposed conductive structure to the corresponding buried conductive segment, the second vertical conductive structure electrically connecting the exposed conductive structure to the corresponding buried conductive segment, and the second vertical conductive structure electrically connecting the exposed conductive structure to the main RF power supply electrode, the first vertical conductive structure electrically connecting the exposed conductive structure to the corresponding buried conductive segment, and the second vertical conductive structure electrically connecting the exposed conductive structure to the main RF power supply electrode, the second ... main RF power supply electrode, and the second vertical conductive structure electrically connecting the exposed conductive structure to the corresponding buried conductive segment.

7. 7. The substrate support system of claim 6, A substrate support system, wherein the first vertical conductive structure comprises a plurality of vertical conductive structures, and the second vertical conductive structure comprises a plurality of vertical conductive structures.

8. 7. The substrate support system of claim 6, further comprising: a substrate support system including one or more resistive heaters positioned within the ceramic assembly at a vertical position below the main RF powered electrode, the peripheral RF powered electrode being positioned at the same vertical position as the one or more resistive heaters.

9. 9. The substrate support system of claim 8, the plurality of electrical connections extend through the ceramic assembly at respective locations radially outward of the one or more resistive heaters relative to a centerline of the ceramic assembly that extends perpendicular to the top surface of the ceramic assembly.

10. There is a ceramic assembly for the electrostatic chuck. a ceramic member having a top surface and a bottom surface, the top surface including an area configured to support a substrate; at least one clamping electrode positioned within the ceramic member; a primary radio frequency (RF) powered electrode positioned within the ceramic member at a location vertically below the at least one clamping electrode, the primary RF powered electrode being radially symmetrically spaced about a centerline of the ceramic member that extends perpendicular to the top surface of the ceramic member, each section of the primary RF powered electrode being spaced apart from an adjacent section of the primary RF powered electrode; a peripheral RF powered electrode having an annular shape positioned within the ceramic assembly at a position vertically below the main RF powered electrode, the outer edge of the peripheral RF powered electrode being positioned farther from a centerline of the ceramic assembly than the outer edge of the main RF powered electrode; a plurality of exposed buried conductive segments positioned to be distributed within a peripheral region of the ceramic member, a portion of each exposed buried conductive segment being accessible from the bottom surface of the ceramic member; a plurality of electrical connections extending respectively between the plurality of exposed buried conductive segments and the main RF power supply electrode, each of the plurality of electrical connections extending through a respective portion of the ceramic member, each section of the main RF power supply electrode being electrically connected to a respective one of the plurality of electrical connections, each of the plurality of electrical connections including a corresponding lower electrical connection extending from the corresponding exposed buried conductive segment to the peripheral RF power supply electrode, and each of the plurality of electrical connections including a corresponding upper electrical connection extending from the peripheral RF power supply electrode to a corresponding section of the main RF power supply electrode; 1. A ceramic assembly for an electrostatic chuck comprising:

11. 11. The ceramic assembly of claim 10, the plurality of electrical connections are positioned at substantially equal intervals when measured azimuthally about a centerline of the ceramic member that extends perpendicular to the top surface of the ceramic member.

12. 11. The ceramic assembly of claim 10, a ceramic assembly for an electrostatic chuck, wherein each of the plurality of electrical connections includes a corresponding inner buried conductive segment, a corresponding first vertical conductive structure, and a corresponding second vertical conductive structure, the corresponding inner buried conductive segment being positioned within the ceramic member at a vertical position between the exposed buried conductive structure of the electrical connection and the main RF power supply electrode, the corresponding first vertical conductive structure electrically connecting the corresponding exposed buried conductive structure of the electrical connection to the corresponding inner buried conductive segment, and the corresponding second vertical conductive structure electrically connecting the corresponding inner buried conductive segment to the main RF power supply electrode.

13. 13. The ceramic assembly of claim 12, comprising: The ceramic assembly for an electrostatic chuck, wherein the first vertical conductive structure includes a plurality of vertical conductive structures, and the second vertical conductive structure includes a plurality of vertical conductive structures.

14. 11. The ceramic assembly of claim 10, a ceramic assembly for an electrostatic chuck, wherein a given one of the plurality of electrical connections includes one or more internally embedded conductive segments within the ceramic member, and the given one of the plurality of electrical connections includes a plurality of vertical conductive structures positioned to electrically connect the one or more internally embedded conductive segments to one another, to the exposed embedded conductive segment of the given one of the plurality of electrical connections, and to the main RF electrical supply electrode.

15. 15. The ceramic assembly of claim 14, comprising:

10. A ceramic assembly for an electrostatic chuck, wherein each of the one or more internally embedded conductive segments is oriented substantially parallel to the main RF powered electrode.

16. 15. The ceramic assembly of claim 14, comprising: at least one of the vertical conductive structures extends through the ceramic member between the exposed buried conductive segment of the given one of the plurality of electrical connections and a lowermost one of the internally buried conductive segments of the given one of the plurality of electrical connections; at least one of the vertical conductive structures extends through the ceramic member between an uppermost one of the internally buried conductive segments of the given one of the plurality of electrical connections and the main RF power supply electrode; and at least one of the vertical conductive structures extends through the ceramic member between every two vertically adjacent ones of the internally buried conductive segments of the given one of the plurality of electrical connections, when present.

17. 11. The ceramic assembly of claim 10, further comprising: a ceramic assembly for an electrostatic chuck, the ceramic assembly including one or more resistive heaters positioned within the ceramic assembly at a vertical location below the main RF powered electrode, the plurality of electrical connections extending through the ceramic member at respective locations radially outward of the one or more resistive heaters relative to a centerline of the ceramic member extending perpendicular to the top surface of the ceramic member.

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