Optimization of RF signal ground return in plasma processing system

Abstract

To provide a plasma processing system achieving the uniformity of plasma processing results on a semiconductor wafer.SOLUTION: A fixed outer support flange 169 is formed to circumscribe an electrode within a plasma processing system. The fixed outer support flange has a vertical portion 169A and a horizontal portion 169B extending radially outward from a lower end of the vertical portion. An articulating outer support flange 171 is formed to circumscribe the fixed outer support flange. The articulating outer support flange has a vertical portion 171A and a horizontal portion 171B extending radially outward from a lower end of the vertical portion. The vertical portion of the articulating outer support flange 2 is positioned concentrically outside of the vertical portion of the fixed outer support flange. The articulating outer support flange is spaced apart from the fixed outer support flange and movable along the vertical portion of the fixed outer support flange. Each of a plurality of electrically conductive straps has a first end portion connected to the articulating outer support flange and a second end portion connected to the fixed outer support flange.SELECTED DRAWING: Figure 4A

Description

Technical Field

[0001] 1. Field of Disclosure

[0002] This disclosure relates to the manufacture of semiconductor devices.

Background Art

[0003] 2. Description of Related Art

[0004] Plasma etching processes are often used in the manufacture of semiconductor devices on semiconductor wafers. In a plasma etching process, a semiconductor wafer containing a semiconductor device being manufactured is exposed to plasma generated within a plasma processing region. The plasma interacts with the materials on the semiconductor wafer to remove materials from the semiconductor wafer and / or modify the materials so that they can then be removed from the semiconductor wafer. The plasma can be generated using a specific reaction gas, whereby the components of the plasma can interact with the materials to be removed / modified on the semiconductor wafer without significantly interacting with the non-removed / modified materials on other wafers. The plasma is generated using RF (Radiofrequency) signals for exciting a specific reaction gas. These RF signals are transmitted within the plasma processing region containing the reaction gas, and the plasma processing region is held such that the semiconductor wafer can be exposed. The transmission path of the RF signal through the plasma processing region can affect how the plasma is generated within the plasma processing region. For example, in the range of the plasma processing region where a larger amount of RF signal power is transmitted, the reaction gas can be more strongly excited, resulting in spatial non-uniformity of plasma characteristics across the plasma processing region. The spatial non-uniformity of plasma characteristics can appear as spatial non-uniformity of ion density, ion energy, and / or reaction component density, among other plasma characteristics. Corresponding to the spatial non-uniformity of plasma characteristics, spatial non-uniformity can also occur in the plasma processing results on the semiconductor wafer. That is, the uniformity of the plasma processing results on the semiconductor wafer can be affected by how the RF signal is transmitted through the plasma processing region. This disclosure is described in such a context.

Summary of the Invention

[0005] In an exemplary embodiment, a plasma processing system is disclosed. The plasma processing system includes an electrode having a substantially upper cylindrical shape defined by a top surface, a bottom surface, and an outer surface. The plasma processing system also includes a ceramic layer formed on the top surface of the electrode. The ceramic layer is configured to receive and support a semiconductor wafer. The plasma processing system also includes an RF signal generator electrically connected to the electrode via an impedance matching system. The RF signal generator is configured to generate an RF signal and supply it to the electrode. The plasma processing system also includes a fixed outer support flange formed to surround the outer surface of the electrode. The fixed outer support flange has a fixed spatial relationship with respect to the electrode. The fixed outer support flange has a vertical portion and a horizontal portion extending radially outward from the lower end of the vertical portion. The fixed outer support flange is electrically connected to a reference ground potential. The plasma processing system also has a connecting outer support flange formed to surround the fixed outer support flange. The connecting outer support flange has a vertical portion and a horizontal portion extending radially outward from the lower end of the vertical portion. The vertical portion of the connecting outer support flange is concentrically disposed outside the vertical portion of the fixed outer support flange. The connecting outer support flange is spaced apart from the fixed outer support flange so as to be movable in a direction perpendicular to the fixed outer support flange. The plasma processing system also includes a plurality of conductive straps. Each of the plurality of conductive straps has a first end connected to the horizontal portion of the connecting outer support flange and a second end connected to the horizontal portion of the fixed outer support flange.

[0006] In an exemplary embodiment, a ground return assembly for a plasma processing system is disclosed. The ground return assembly includes a fixed outer support flange formed to surround an electrode within the plasma processing system and having a fixed spatial relationship with respect to the electrode. The fixed outer support flange has a vertical portion and a horizontal portion extending radially outward from a lower end of the vertical portion. The ground return assembly also has a connecting outer support flange formed to surround the fixed outer support flange. The connecting outer support flange has a vertical portion and a horizontal portion extending radially outward from a lower end of the vertical portion. The vertical portion of the connecting outer support flange is concentrically disposed outside the vertical portion of the fixed outer support flange. The connecting outer support flange is spaced apart from the fixed outer support flange so as to be movable along the vertical portion of the fixed outer support flange. The ground return assembly also includes a plurality of conductive straps. Each of the plurality of conductive straps has a first end connected to the connecting outer support flange and a second end connected to the fixed outer support flange.

[0007] In an exemplary embodiment, a plasma processing system is disclosed. The plasma processing system includes an electrode formed of a conductive material. The electrode has a substantially upper cylindrical shape defined by a top surface, a bottom surface, and an outer surface. The plasma processing system also includes a ceramic layer formed on the top surface of the electrode. The ceramic layer is configured to receive and support a semiconductor wafer. The plasma processing system also includes a facility plate formed of a conductive material. The bottom surface of the electrode is physically and electrically connected to the top surface of the facility plate. The plasma processing system also includes an RF signal supply shaft formed of a conductive material. The upper end of the RF signal supply shaft is physically and electrically connected to the bottom surface of the facility plate. The plasma processing system also includes an RF signal supply rod formed of a conductive material. The lower end of the RF signal supply shaft is physically and electrically connected to the sending end of the RF signal supply rod. The plasma processing system also includes an RF signal generator electrically connected to the supply end of the RF signal supply rod via an impedance matching system. The plasma processing system also includes a tube disposed around the RF signal supply rod. The tube is formed of a conductive material. The tube has an inner wall separated from the RF signal supply rod by air along the entire length of the tube.

[0008] In an exemplary embodiment, an RF signal supply structure for a plasma processing system is disclosed. The RF signal supply structure includes an RF signal supply rod formed of a conductive material. The RF signal supply rod has a supply end and a sending end. The supply end of the RF signal supply rod is configured for connection to an impedance matching system disposed between the RF signal supply rod and an RF signal generator. The RF signal supply structure also includes a tube disposed around the RF signal supply rod. The tube is formed of a conductive material. The tube has an inner wall separated from the RF signal supply rod by air along the entire length of the tube.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0024] In the following description, for the understanding of the embodiments of the present disclosure, a number of specific details are set forth. However, it will be apparent to those skilled in the art that the embodiments of the present disclosure can be practiced without some or all of these specific details. In other instances, well-known processing operations are omitted in order to avoid unnecessarily obscuring the present disclosure.

[0025] In a plasma etching system for semiconductor wafer manufacturing, the spatial variation of the etching result across the entire semiconductor wafer is characterized by the radial etching uniformity and the azimuthal etching uniformity. The radial etching uniformity can be characterized by the variation of the etching rate as a function of the radial position on the semiconductor wafer extending outward from the center of the semiconductor wafer to the edge of the semiconductor wafer at a given azimuthal position on the semiconductor wafer. Also, the azimuthal etching uniformity can be characterized by the variation of the etching rate as a function of the azimuthal position on the semiconductor wafer centered on the center of the semiconductor wafer at a given radial position on the semiconductor wafer. In some plasma processing systems such as the system described herein, the semiconductor wafer is disposed on an electrode from which an RF signal is emitted to generate a plasma within a plasma generation region covering the semiconductor wafer. The plasma has characteristics that are controlled to cause a predetermined etching process on the semiconductor wafer.

[0026] The RF signal generated from the electrode below the semiconductor wafer travels through the plasma generation region covering the semiconductor wafer and reaches the surrounding electrical reference ground potential feedback path. The spatial arrangement and configuration of these surrounding electrical reference ground potential feedback paths can affect how the RF signal spatially moves through the plasma generation region and can affect the impedance seen by the RF signal, and as a result, can further affect both the RF signal power delivered to the plasma and the spatial variation of plasma characteristics across the plasma generation region. This specification discloses various systems that enable improvements in both the configuration and control of the RF signal reference ground feedback path within a plasma processing system, thereby seeking to improve the uniformity of semiconductor processing results across the wafer, including improvements in both the radial etching uniformity and the azimuthal etching uniformity across the entire semiconductor wafer.

[0027] FIG. 1A shows a vertical cross-sectional view of a plasma processing system 100 used for semiconductor chip manufacturing according to some embodiments. The system 100 includes a chamber 101 formed by a wall 101A, an upper member 101B, and a bottom member 101C. The wall 101A, the upper member 101B, and the bottom member 101C collectively form an internal region 103 within the chamber 101. The bottom member 101C includes an exhaust port 105 to which the exhaust gas of the plasma processing operation is directed. In some embodiments, during operation, a suction force is applied to the exhaust port 105 by a turbo pump or other vacuum device to draw the process exhaust gas from the internal region 103 of the chamber 101. In some embodiments, the chamber 101 is formed of aluminum. However, in various embodiments, the chamber 101 can be formed of any material that essentially has sufficient mechanical strength and acceptable thermal performance and also has chemical compatibility with other materials that come into contact with and are exposed to during the plasma processing operation within the chamber 101, such as stainless steel. At least one wall 101A of the chamber 101 includes a door 107 through which the semiconductor wafer W passes when being transferred in and out of the chamber 101. In some embodiments, the door 107 is configured as a slit valve door.

[0028] In some embodiments, semiconductor wafer W is a semiconductor wafer in a manufacturing process. For ease of explanation, semiconductor wafer W is hereinafter referred to as wafer W. However, in various embodiments, wafer W can be essentially any type of substrate that is subjected to a plasma-based manufacturing process. For example, in some embodiments, wafer W referred to herein can be a substrate formed from silicon, sapphire, GaN, GaAs, or SiC, or other substrate materials, and can include glass panels / substrates, metal foils, metal sheets, polymer materials, and the like. Also, in various embodiments, wafer W referred to herein can vary in form, shape, and / or size. For example, in some embodiments, wafer W referred to herein can be a circular semiconductor wafer on which integrated circuit devices are manufactured. In various embodiments, the circular wafer W can have a diameter of 200 millimeters (mm), 300 mm, 450 mm, or other sizes. Also, in some embodiments, wafer W referred to herein can be a non-circular substrate, such as a rectangular substrate for a flat panel display, for example.

[0029] Plasma processing system 100 includes an electrode 109 disposed on a facility plate 111. In some embodiments, electrode 109 and facility plate 111 are formed of aluminum. However, in other embodiments, electrode 109 and facility plate 111 can be formed of other conductive materials having sufficient mechanical strength and being compatible as thermal and chemical performance characteristics. Ceramic layer 110 is formed on the top surface of electrode 109. In some embodiments, the ceramic layer has a vertical thickness of about 1.25 millimeters (mm) when measured perpendicular to the top surface of electrode 109. However, in other embodiments, ceramic layer 110 can have a vertical thickness greater than or less than 1.25 mm. Ceramic layer 110 is configured to receive and support wafer W during the plasma processing operation on wafer W. In some embodiments, the top surface of electrode 190 located radially outside of ceramic layer 110 and the peripheral side surface of electrode 109 are covered with a ceramic spray coat.

[0030] Ceramic layer 110 includes a configuration of one or more clamp electrodes 112 for generating an electrostatic force to hold wafer W on the top surface of ceramic layer 110. In some embodiments, ceramic layer 110 includes a configuration of two clamp electrodes 112 operating in a bipolar manner to supply a clamping force to wafer W. Clamp electrodes 112 are connected to a direct current (DC) power supply 117 that generates a controlled clamping voltage for holding wafer W on the top surface of ceramic layer 110. Electrical wires 119A, 119B are connected between DC power supply 117 and facility plate 111. The electrical wire / conductor is wired through facility plate 111 and electrode 109 to electrically connect wires 119A, 119B to clamp electrodes 112. DC power supply 117 is connected to control system 120 via one or more signal conductors 121.

[0031] Electrode 109 also includes the configuration of a temperature control fluid channel 123 through which a temperature control fluid flows to control the temperature of the electrode 109 and further control the temperature of the wafer W. The temperature control fluid channel 123 is piped (fluidly connected) to ports on the facility plate 111. The temperature control fluid supply line and return line are connected to these ports on the facility plate 111 and the temperature control fluid circulation system 125 as indicated by the arrow 126. The temperature control fluid circulation system 125 includes a temperature control fluid source, a temperature control fluid pump, and heat exchangers and other devices, and controls the flow of the temperature control fluid through the electrode 109 to set and maintain a predetermined wafer W temperature. The temperature control fluid circulation system 125 is connected to the control system 120 via one or more signal conductors 127. In various embodiments, various types of temperature control fluids such as water or a refrigerant liquid / gas can be used. Also, in some embodiments, the temperature control fluid channel 123 is configured to enable control to spatially vary the temperature of the wafer W, for example, in two dimensions (x and y) across the entire wafer W.

[0032] The ceramic layer 110 also includes a configuration of a back gas supply port 108 (see FIG. 2) that is fluidly connected to a corresponding back gas supply channel within the electrode 109. The back gas supply channel within the electrode 109 is wired through the electrode 109 to an interface between the electrode 109 and the facility plate 111. One or more back gas supply lines are connected to ports on the facility plate 111 and a back gas supply system 129, as indicated by the arrow 130. The facility plate 111 is configured to supply back gas from one or more back gas supply lines to the back gas supply channel within the electrode 109. The back gas supply system 129 includes a back gas supply source, a mass flow controller, a flow control valve, and other devices, and supplies a controlled back gas flow through the configuration of the back gas supply port 108 within the ceramic layer 110. In some embodiments, the back gas supply system 129 also includes one or more components for controlling the temperature of the back gas. In some embodiments, the back gas is helium. Also in some embodiments, the back gas supply system 129 can be used to supply clean dry air (CDA) to the configuration of the back gas supply port 108 within the ceramic layer 110. The back gas supply system 129 is connected to the control system 120 via one or more signal conductors 131.

[0033] The three lift pins 132 extend through the facility plate 111, the electrode 109, and the ceramic layer 110, enabling vertical movement of the wafer W relative to the top surface of the ceramic layer 110. In some embodiments, the vertical movement of the lift pins 132 is controlled by corresponding electromechanical and / or pneumatic lift devices 133 connected to the facility plate 111. The three lift devices 133 are connected to the control system 120 via one or more signal conductors 134. In some embodiments, the three lift pins 132 are arranged to have substantially equal azimuthal intervals with respect to the vertical centerline of the electrode 109 / ceramic layer 110 that extends vertically to the top surface of the ceramic layer 110. Note that the lift pins 132 receive the wafer W into the chamber 101 and take out the wafer W from the chamber 101 by rising. Also, the lift pins 132 place the wafer W on the top surface of the ceramic layer 110 during the processing of the wafer W by descending.

[0034] FIG. 2 shows a top view of the ceramic layer 110 and the electrode 109 according to some embodiments. An exemplary arrangement of the clamp electrodes 112 is shown within the ceramic layer 110. Note that since the clamp electrodes 112 are arranged within the vertical thickness of the ceramic layer 110, a portion of the ceramic layer 110 exists above the clamp electrodes 112. FIG. 2 also shows an exemplary arrangement of the back gas supply ports 108. Note that the number and spatial arrangement of the back gas supply ports 108 may vary in different embodiments. In some embodiments, the back gas supply ports 108 are filled with a porous ceramic material that allows a back gas flow through the back gas supply ports 108 and simultaneously supplies a solid surface at the location of the back gas supply ports 108. FIG. 2 also shows an exemplary arrangement of the three lift pins 132.

[0035] Also, in various embodiments, one or more of the electrode 109, the facility plate 111, the ceramic layer 110, the clamp electrode 112, the lift pin 132, and essentially any other component related thereto may include one or more sensors, such as sensors for temperature measurement, voltage measurement, and current measurement. Any sensors disposed on the electrode 109, the facility plate 111, the ceramic layer 110, the clamp electrode 112, the lift pin 132, and essentially any other component related thereto are connected to the control system 120 via an electrical wire, an optical fiber, or a wireless connection.

[0036] The facility plate 111 is set within an opening of the ceramic support 113 and is supported by the ceramic support 113. The ceramic support 113 is disposed on the support surface 114 of the cantilever arm assembly 115. In some embodiments, the ceramic support 113 has a substantially annular shape, such that the ceramic support 113 substantially surrounds the radially outer periphery of the facility plate 111 and at the same time provides a support surface 116 on which the bottom outer peripheral surface of the facility plate 111 is placed. The cantilever arm assembly 115 extends through the wall 101A of the chamber 101. In some embodiments, a sealing mechanism 135 is provided within the wall 101A of the chamber 101 in which the cantilever arm assembly 115 is disposed to seal the internal region 103 of the chamber 101 and at the same time enables the cantilever arm assembly 115 to move vertically in the z - direction in a controlled manner.

[0037] The cantilever arm assembly 115 has an open area 118 where various devices, wires, cables, and tubes are routed to support the operation of the system 100. The open area 118 within the cantilever arm assembly is exposed to the ambient conditions outside the chamber 101, such as air composition, temperature, pressure, and relative humidity. Also, an RF signal supply rod 137 is disposed inside the cantilever arm assembly 115. More specifically, the RF signal supply rod 137 is disposed inside a conductive tube 139, and the RF signal supply rod 137 is spaced from the inner wall of the tube 139. In some embodiments, the tube 139 has an inner diameter in the range of about 1.5 inches to about 6 inches. In some embodiments, the RF signal supply rod 137 has an outer diameter in the range of about 0.75 inches to about 2 inches. In some embodiments, the difference between the inner diameter of the tube 139 and the outer diameter of the RF signal supply rod 137 is in the range of about 0.25 inches to about 4 inches. The sizes of the RF signal supply rod 137 and the tube 139 are changeable. The region between the inner wall of the tube 139 and the RF signal supply rod 137 inside the tube 139 is occupied by air along the entire length of the tube 139. In some embodiments, the outer diameter (D rod ) of the RF signal supply rod 137 and the inner diameter (D tube ) of the tube 139 are set to satisfy the relationship of ln(D tube / D rod ) >= e 1 .

[0038] In some embodiments, the RF signal supply rod 137 is disposed substantially centrally within the tube 139, and air having a substantially uniform radial thickness exists between the RF signal supply rod 137 and the inner wall of the tube 139 along the length of the tube 139. However, in some embodiments, the RF signal supply rod 137 is not disposed centrally within the tube 139. Nevertheless, within the tube 139, gaps along the length of the tube 139 exist at all positions between the RF signal supply rod 137 and the inner wall of the tube 139. The output end of the RF signal supply rod 137 is electrically and physically connected to the lower end of the RF signal supply shaft 141. In some embodiments, the output end of the RF signal supply rod 137 is bolted to the lower end of the RF signal supply shaft 141. The upper end of the RF signal supply shaft 141 is electrically and physically connected to the bottom of the facility plate 111. In some embodiments, the upper end of the RF signal supply shaft 141 is bolted to the bottom of the facility plate 111. In some embodiments, both the RF signal supply rod 137 and the RF signal supply shaft 141 are formed of copper. In some embodiments, the RF signal supply rod 137 is formed of copper, aluminum, or anodized aluminum. In some embodiments, the RF signal supply shaft 141 is formed of copper, aluminum, or anodized aluminum. In other embodiments, the RF signal supply rod 137 and / or the RF signal supply shaft 141 are formed of another conductive material that enables the transmission of RF electrical signals. In some embodiments, the RF signal supply rod 137 and / or the RF signal supply shaft 141 are coated with a conductive material (such as silver or other conductive materials) that enables the transmission of RF electrical signals. Also, in some embodiments, the RF signal supply rod 137 is a solid rod. However, in other embodiments, the RF signal supply rod 137 is a tube. Note that the region 140 surrounding the connection between the RF signal supply rod 137 and the RF signal supply shaft 141 is occupied by air.

[0039] The supply end of the RF signal supply rod 137 is electrically and physically connected to the impedance matching system 143. The impedance matching system 143 is connected to the first RF signal generator 147 and the second RF signal generator 149. The impedance matching system 143 is also connected to the control system 120 via one or more signal conductors 144. The first RF signal generator 147 is also connected to the control system 120 via one or more signal conductors 148. The second RF signal generator 149 is also connected to the control system 120 via one or more signal conductors 150. The impedance matching system 143 includes a configuration of inductors and capacitors sized and connected to enable impedance matching, whereby RF power can be transmitted along the RF signal supply rod 137 and the RF signal supply shaft 141, through the facility plate 111 and the electrode 109, to the plasma processing region 182 above the ceramic layer 110. In some embodiments, the first RF signal generator 147 is a high-frequency RF signal generator and the second RF signal generator 149 is a low-frequency RF signal generator. In some embodiments, the first RF signal generator 147 generates an RF signal in the range of about 50 megahertz (MHz) to about 70 MHz, or in the range of about 54 MHz to about 63 MHz, or at about 60 MHz. In some embodiments, the first RF signal generator 147 supplies RF power in the range of about 5 kilowatts (kW) to about 25 kW, or in the range of about 10 kW to about 20 kW, or in the range of about 15 kW to about 20 kW, or at about 10 kW or about 16 kW. In some embodiments, the second RF signal generator 149 generates an RF signal in the range of about 50 kilohertz (kHz) to about 500 kHz, or in the range of about 330 kHz to about 440 kHz, or at about 400 kHz. In some embodiments, the second RF signal generator 149 supplies RF power in the range of about 15 kW to about 100 kW, or in the range of about 30 kW to about 50 kW, or at about 34 kW or about 50 kW. In an exemplary embodiment, the first RF signal generator 147 is set to generate an RF signal of about 60 MHz and the second RF signal generator 149 is set to generate an RF signal of about 400 kHz.

[0040] FIG. 3 shows an electrical schematic diagram of an impedance matching system 143 according to some embodiments. The impedance matching system 143 includes a first branch 302A (high-frequency branch) and a second branch 302B (low-frequency branch). The first branch 302A includes circuit components such as an inductor L4, capacitors C2, C7, and C3. The second branch 302B includes circuit components such as inductors L1, L2, capacitors C1, C4, C5, C6, and an inductor L3. In some embodiments, capacitors C1, C2, and C3 are variable capacitors. Capacitors C1 and C2 are main capacitors, and capacitor C3 is a spare capacitor. Inductors L1, L2, L3, and L4 are each formed as a coil made of a conductive material, such as copper. The first branch 302A has an input I1 connected to the output of a first RF signal generator 147. The second branch 302B has an input I2 connected to the output of a second RF signal generator 149. Input I2 is connected to inductor L1.

[0041] As an example, the RF strap referred to herein is a flat and elongated metal piece made of a conductive material such as copper. Thus, the RF strap has a length, a width, and a thickness. The length of the RF strap is greater than the width of the RF strap. Further, the width of the RF strap is greater than the thickness of the RF strap. In some embodiments, the RF strap is flexible to allow for its curvature or reformation.

[0042] The first branch 302A includes an RF strap portion 304A (represented as inductor LA), an RF strap portion 304B (represented as inductor LB), an RF strap 304C (represented as inductor LC), an RF strap 304D (represented as inductor LD), and an RF strap 304E (represented as inductor LE). In some embodiments, the RF strap portions 304A and 304B are separate portions of one RF strap, that is, the inductors LA and LB represent separate portions of one RF strap. However, in some embodiments, instead of one RF strap including two RF strap portions 304A and 304B, two separate RF straps are used as the RF strap portions 304A and 304B, respectively. For example, a first RF strap having the inductance of the RF strap portion 304A is connected via a conductive connector to a second RF strap having the inductance of the RF strap portion 304B.

[0043] Capacitor C3 is coupled to a predetermined position P1 on an RF strap including both RF strap portions 304A and 304B via an RF strap 304C. In this way, the predetermined position P1 where the RF strap 304C is connected to the RF strap including both RF strap portions 304A and 304B determines the respective lengths of the RF strap portions 304A and 304B. Also, capacitor C7 is coupled to an end of the RF strap portion 304A opposite to the predetermined position P1. The predetermined position P1 is coupled to the RF signal supply rod 137 via the RF strap portion 304B. The RF straps 304D and 304E are coupled to each other at a predetermined position P2. The terminal of capacitor C2 is also connected to the predetermined position P2. The RF strap 304D is coupled to the inductor L4 and the input I1 of the impedance matching system 143. Each of the RF strap portions 304A and 304B, and each of the RF straps 304C, 304D, and 304E has an inductance. For example, the RF strap portion 304A has an inductance LA, the RF strap portion 304B has another inductance LB, the RF strap 304C has another inductance LC, the RF strap 304D has an inductance LD, and the RF strap 304E has an inductance LE. Note that any of the RF straps such as the RF straps 304A to 304E described in this specification is not formed by winding around a coil to form an inductor, but is a flat and elongated metal piece.

[0044] In various embodiments, any of the capacitors and / or non-strap inductors shown in FIG. 3 can be fixed or variable. For example, in various embodiments, any one or more of capacitors C4 - C7 are fixed capacitors, meaning that their inductance cannot be changed or adjusted. Also, in some embodiments, any one or more of capacitors C4 - C7 are variable capacitors, meaning that their capacitance can be changed / adjusted. In various embodiments, any one or more of inductors L1 - L4 are fixed inductors, meaning that their inductance cannot be changed or adjusted. Also, in various embodiments, any one or more of inductors L1 - L4 are variable inductors, meaning that their inductance can be changed or adjusted.

[0045] Referring back to FIG. 1A, the ceramic ring 161 is configured and positioned to extend around the radial outer periphery of the electrode 109. Also, in some embodiments, the first quartz ring 163 is configured and positioned to extend around the radial outer peripheries of both the ceramic ring 161 and the ceramic support 113. In some embodiments, the ceramic ring 161 and the first quartz ring 163 are configured to have substantially aligned top surfaces when the first quartz ring 163 is disposed around both the ceramic ring 161 and the ceramic support 113. Also, in some embodiments, the substantially aligned top surfaces of the ceramic ring 161 and the first quartz ring 163 are substantially aligned with the top surface of the electrode 109 that exists outside the radial periphery of the ceramic layer 110. Also, in some embodiments, the second quartz ring 165 is configured and positioned to extend around the radial outer periphery of the top surface of the first quartz ring 163. Also, in some embodiments, the second quartz ring 165 is configured to extend vertically above the top surface of the first quartz ring 163. Thus, the second quartz ring 165 forms the outer peripheral boundary where the edge ring 167 is disposed.

[0046] The edge ring 167 is configured to facilitate the extension of the plasma sheath radially outward beyond the peripheral portion of the wafer W and improve the processing result in the vicinity of the periphery of the wafer W. In various embodiments, the edge ring 167 is made of a conductive material, such as crystalline silicon, polycrystalline silicon (polysilicon), boron-doped single-crystalline silicon, aluminum oxide, quartz, aluminum nitride, silicon nitride, silicon carbide, or a silicon carbide layer on an aluminum oxide layer, or an alloy of silicon, or a combination thereof, and other materials. Note that the edge ring 167 is formed as an annular structure, for example, a ring structure. The edge ring 167 can perform many functions, such as shielding the components under the edge ring 167 to prevent damage by the ions of the plasma 180 formed in the plasma processing region 182. Further, the edge ring 167 enhances the uniformity of the plasma 180 in the outer peripheral edge region of the wafer W and along the outer peripheral edge region.

[0047] The fixed outer support flange 169 is attached to the cantilever arm assembly 115. FIG. 4A shows an enlarged view of a vertical cross-section of the fixed outer support flange 169 according to some embodiments. The fixed outer support flange 169 is configured to extend around the outer vertical side surface 113A of the ceramic support 113, around the outer vertical side surface 163A of the first quartz ring 163, and around the lower outer vertical side surface 165A of the second quartz ring 165. The fixed outer support flange 169 has an annular shape that surrounds the assembly of the ceramic support 113, the first quartz ring 163, and the second quartz ring 165. The fixed outer support flange 169 has an L-shaped vertical cross-section that includes a vertical portion 169A and a horizontal portion 169B. The vertical portion 169A of the L-shaped cross-section of the fixed outer support flange 169 has an inner vertical surface 169C that is disposed opposite the outer vertical side surface 113A of the ceramic support 113, the outer vertical side surface 163A of the first quartz ring 163, and the lower outer vertical side surface 165A of the second quartz ring 165. In some embodiments, the vertical portion 169A of the L-shaped cross-section of the fixed outer support flange 169 extends entirely around the outer vertical side surface 113A of the ceramic support 113, entirely around the outer vertical side surface 163A of the first quartz ring 163, and entirely around the lower outer vertical side surface 165A of the second quartz ring 165. In some embodiments, the second quartz ring 165 extends radially outward above the top surface 169E of the vertical portion 169A of the L-shaped cross-section of the fixed outer support flange 169. In some embodiments, the upper outer vertical side surface 165B of the second quartz ring 165 (which is located above the top surface 169E of the vertical portion 169A of the L-shaped cross-section of the fixed outer support flange 169) is substantially vertically aligned with the outer vertical surface 169D of the vertical portion 169A of the L-shaped cross-section of the fixed outer support flange 169. The horizontal portion 169B of the L-shaped cross-section of the fixed outer support flange 169 is disposed and fixed on the support surface 114 of the cantilever arm assembly 115. The fixed outer support flange 169 is formed of a conductive material. In some embodiments, the fixed outer support flange 169 is formed of aluminum or anodized aluminum. However, in other embodiments, the fixed outer support flange 169 may be formed of other conductive materials such as copper or stainless steel.In some embodiments, the horizontal portion 169B of the L-shaped cross-section of the fixed outer support flange 169 is bolted to the support surface 114 of the cantilever arm assembly 115.

[0048] The connecting outer support flange 171 is configured and positioned to extend around at least a portion of the outer vertical surface 169D of the vertical portion 169A of the L-shaped cross-section of the fixed outer support flange 169 and around the upper outer vertical side surface 165B of the second quartz ring 165. The connecting outer support flange 171 has an annular shape that surrounds both at least a portion of the vertical portion 169A of the L-shaped vertical cross-section of the fixed outer support flange 169 and the upper outer vertical side surface 165B of the second quartz ring 165. The connecting outer support flange 171 has an L-shaped vertical cross-section including a vertical portion 171A and a horizontal portion 171B. The vertical portion 171A of the L-shaped cross-section of the connecting outer support flange 171 has an inner vertical surface 171C that is close to and spaced apart from both at least a portion of the outer vertical side surface 169D of the vertical portion 169A of the L-shaped cross-section of the fixed outer support flange 169 and the upper outer vertical side surface 165B of the second quartz ring 165. Thus, the connecting outer support flange 171 is movable in the vertical direction (z-direction) along both the vertical portion 169A of the L-shaped vertical cross-section of the fixed outer support flange 169 and the upper outer vertical side surface 165B of the second quartz ring 165, as indicated by arrow 172. The connecting outer support flange 171 is formed of a conductive material. In some embodiments, the connecting outer support flange 171 is formed of aluminum or anodized aluminum. However, in other embodiments, the connecting outer support flange 171 may be formed of other conductive materials such as copper or stainless steel.

[0049] A plurality of conductive straps 173 are connected between the connecting outer support flange 171 and the fixed outer support flange 169 around the circumferences of the radially outer perimeters of both the connecting outer support flange 171 and the fixed outer support flange 169. FIG. 5 shows a top view of the connecting outer support flange 171 and the fixed outer support flange 169 according to some embodiments, showing the plurality of conductive straps 173 connected between the connecting outer support flange 171 and the fixed outer support flange 169. FIG. 6 shows a perspective view of the tops of the connecting outer support flange 171 and the fixed outer support flange 169 according to some embodiments, showing the plurality of conductive straps 173 connected between the connecting outer support flange 171 and the fixed outer support flange 169. In some embodiments, the conductive straps 173 are formed of stainless steel. However, in other embodiments, the conductive straps 173 may be formed of other conductive materials such as aluminum or copper.

[0050] In the examples of FIGS. 1A, 1B, 5, and 6, 48 conductive straps 173 are substantially evenly distributed around the radial outer periphery of the connecting outer support flange 171 and the fixed outer support flange 169. However, the number of conductive straps 173 can be changed in different embodiments. In some embodiments, the number of conductive straps 173 is in the range of about 24 to about 80, or in the range of about 36 to about 60, or in the range of about 40 to about 56. In some embodiments, the number of conductive straps 173 is less than 24. In some embodiments, the number of conductive straps 173 exceeds 80. Since the number of conductive straps 173 affects the ground return path of the RF signal in the vicinity around the plasma processing region 182, the number of conductive straps 173 can affect the uniformity of the processing results across the entire wafer W. Also, the size of the conductive strap 173 can vary in different embodiments. FIG. 7 shows an isometric view of the conductive strap 173 according to some embodiments. The conductive strap 173 has a rectangular prism shape defined by a width (d1), a length (d2), and a thickness (d3). In some embodiments, the width (d1) of the conductive strap 173 is in the range of about 0.125 inches to about 2 inches. In some embodiments, the length (d2) of the conductive strap 173 is in the range of about 2 inches to about 10 inches. In some embodiments, the thickness (d3) of the conductive strap 173 is in the range up to about 0.125 inches.

[0051] Further, FIG. 5 shows the azimuthal angle interval (d4) between adjacent conductive straps 173 when connected between the connecting outer support flange 171 and the fixed outer support flange 169. In some embodiments, the conductive straps 173 are arranged substantially equidistantly around the outer periphery of the connecting outer support flange 171 and, similarly, around the outer periphery of the fixed outer support flange 169. Thus, in these embodiments, the azimuthal angle interval (d4) between adjacent conductive straps 173 around the outer periphery of the horizontal portion 171B of the L-shaped vertical cross-section of the connecting outer support flange 171 depends on the number of conductive straps 173, the width dimension (d1) of the conductive straps 173, and the outer diameter of the horizontal portion 171B of the L-shaped vertical cross-section of the connecting outer support flange 171. Similarly, the azimuthal angle interval (d4) between adjacent conductive straps 173 around the outer periphery of the horizontal portion 169B of the L-shaped vertical cross-section of the fixed outer support flange 169 depends on the number of conductive straps 173, the width dimension (d1) of the conductive straps 173, and the outer diameter of the horizontal portion 169B of the L-shaped vertical cross-section of the fixed outer support flange 169. In some embodiments, the azimuthal angle interval (d4) between adjacent conductive straps 173 is in the range from about 0.125 inches to about 4 inches.

[0052] In some embodiments, the conductive strap 173 is connected to the fixed outer support flange 169 by a clamping force applied by fixing the clamping ring 175 to the top surface 169F of the horizontal portion 169B of the L-shaped cross-section of the fixed outer support flange 169. In some embodiments, the clamping ring 175 is bolted to the fixed outer support flange 169. In some embodiments, the bolts that fix the clamping ring 175 to the fixed outer support flange 169 are arranged at positions between the conductive straps 173. However, in some embodiments, one or more bolts that fix the clamping ring 175 to the fixed outer support flange 169 may be arranged to extend through the conductive straps 173. In some embodiments, the clamping ring 175 is formed of the same material as the fixed outer support flange 169. However, in other embodiments, the clamping ring 175 and the fixed outer support flange 169 may be formed of different materials.

[0053] In some embodiments as shown in FIG. 4A, the conductive strap 173 is connected to the connecting outer support flange 171 by a clamping force applied by fixing a clamping ring 177 to the bottom surface 171D of the horizontal portion 171B of the L-shaped cross-section of the connecting outer support flange 171. FIG. 4B shows a modification of FIG. 4A according to some embodiments, showing how the first end of each of the plurality of conductive straps 173 is connected to the upper surface 171F of the horizontal portion 171B of the connecting outer support flange 171 by a clamping ring 177. In some embodiments, the clamping ring 177 is bolted to the connecting outer support flange 171. In some embodiments, the bolts fixing the clamping ring 177 to the connecting outer support flange 171 are arranged at positions between the conductive straps 173. However, in some embodiments, one or more bolts fixing the clamping ring 177 to the connecting outer support flange 171 may be arranged to extend through the conductive strap 173. In some embodiments, the clamping ring 177 is formed of the same material as the connecting outer support flange 171. However, in other embodiments, the clamping ring 177 and the connecting outer support flange 171 may be formed of different materials.

[0054] A set of support rods 201 is arranged around the cantilever arm assembly 115 and extends vertically through the horizontal portion 169B of the L-shaped cross-section of the fixed outer support flange 169. The upper end of the support rod 201 is configured to engage with the bottom surface 171D of the horizontal portion 171B of the L-shaped cross-section of the connecting outer support flange 171. In some embodiments, each lower end of the support rod 201 engages with a resistance mechanism 203. The resistance mechanism 203 is configured to apply an upward force to the corresponding support rod 201, which allows some downward movement of the support rod 201 but resists the downward movement of the support rod 201. In some embodiments, the resistance mechanism 203 includes a spring for applying an upward force to the corresponding support rod 201. In some embodiments, the resistance mechanism 203 includes a material such as a spring and / or rubber having a spring constant sufficient to apply an upward force to the corresponding support rod 201. When the connecting outer support flange 171 moves downward to engage with the set of support rods 201, the set of support rods 201 and the corresponding resistance mechanism 203 apply an upward force to the connecting outer support flange 171. In some embodiments, the set of support rods 201 includes three support rods 201 and the corresponding resistance mechanism 203. In some embodiments, the support rods 201 are arranged to have substantially equal azimuthal intervals with respect to the vertical centerline of the electrode 109. However, in other embodiments, the support rods 201 are arranged to have unequal azimuthal intervals with respect to the vertical centerline of the electrode 109. Also, in some embodiments, more than three support rods 201 and the corresponding resistance mechanism 203 are provided to support the connecting outer support flange 171.

[0055] Referring back to FIG. 1A, the plasma processing system 100 further includes a C-shroud member 185 disposed above the electrode 109. The C-shroud member 185 is configured to interface and connect with the connecting outer support flange 171. Specifically, by disposing a seal 179 on the top surface 171E of the horizontal portion 171B of the L-shaped cross-section of the connecting outer support flange 171, when the connecting outer support flange 171 moves upward toward the C-shroud member 185, the seal 179 is engaged by the C-shroud member 185. In some embodiments, the seal 179 is conductive to facilitate establishing electrical conduction between the C-shroud member 185 and the connecting outer support flange 171. In some embodiments, the C-shroud member 185 is formed of polysilicon. However, in other embodiments, the C-shroud member 185 is formed of another type of conductive material that is chemically compatible with the processes formed in the plasma processing region 182 and has sufficient mechanical strength.

[0056] The C-shroud is configured to extend around the plasma processing region 182 and radially extend the scope of the plasma processing region 182 into the region defined within the C-shroud member 185. The C-shroud member 185 includes a lower wall 185A, an outer vertical wall 185B, and an upper wall 185C. In some embodiments, the outer vertical wall 185B and the upper wall 185C of the C-shroud member 185 are solid non-perforated members, and the lower wall 185A of the C-shroud member 185 includes a number of vents 186 for flowing process gas from within the plasma processing region 182. In some embodiments, a throttle member 196 is disposed below the vents 186 of the C-shroud member 185 to control the flow of process gas through the vents 186. More specifically, in some embodiments, the throttle member 196 is configured to move vertically up and down perpendicular to the z-direction with respect to the C-shroud member 185 to control the flow of process gas through the vents 186. In some embodiments, the throttle member 196 is configured to engage and / or enter the vents 186.

[0057] The upper wall 185C of the C-shroud member 185 is configured to support the upper electrodes 187A / 187B. In some embodiments, the upper electrodes 187A / 187B include an inner upper electrode 187A and an outer upper electrode 187B. Alternatively, in some embodiments, the inner upper electrode 187A is present, but the outer upper electrode 187B is not present, and the inner upper electrode 187A extends radially to the location where the outer upper electrode 187B should be. In some embodiments, the inner upper electrode 187A is formed of single crystal silicon, and the outer upper electrode 187B is formed of polysilicon. However, in other embodiments, the inner upper electrode 187A and the outer upper electrode 187B may be formed of other materials that are structurally, chemically, electrically, and mechanically compatible with the processes implemented within the plasma processing region 182. The inner upper electrode 187A includes a number of through ports 197 defined as holes that penetrate the entire vertical thickness of the inner upper electrode 187A. The through ports 197 are distributed throughout the inner upper electrode 187A with respect to the x-y plane, and provide a flow of process gas from the plenum region 188 above the upper electrodes 187A / 187B to the plasma processing region 182 below the upper electrodes 187A / 187B.

[0058] FIG. 8A shows a vertical cross-sectional view of the upper electrodes 187A / 187B according to some embodiments. In some embodiments, the inner upper electrode 187A includes a plate 211 formed of a semiconductor material such as single crystal silicon. In some embodiments, a highly conductive layer 213 is formed on and integrated with the top surface of the plate 211. The highly conductive layer 213 has a lower electrical resistance than the semiconductor material of the plate 211. Each through port 197 extends through the entire thickness of the inner upper electrode 187A from the top surface 215 to the bottom surface 217 of the inner upper electrode 187A. As described above, the inner upper electrode 187A physically separates the process gas plenum region 188 from the plasma processing region 182 and is configured to provide a flow of process gas from the process gas plenum region 188 to the plasma processing region 182 through the distribution of the through ports 197.

[0059] FIG. 8B shows a top view of the upper electrodes 187A / 187B according to some embodiments. FIG. 8B shows an exemplary distribution of the through-holes 197 throughout the inner upper electrode 187A. Note that the distribution of the through-holes 197 throughout the inner upper electrode 187A may be configured in a different format in another embodiment. For example, the total number of the through-holes 197 in the inner upper electrode 187A and / or the spatial distribution of the through-holes 197 in the inner upper electrode 187A may vary in another embodiment. Also, the diameter of the through-holes 197 may vary in another embodiment. Generally, it is important to reduce the diameter of the through-holes 197 to a size small enough to prevent the intrusion of the plasma 180 from the plasma processing region 182 into the through-holes 197. In some embodiments, when the diameter of the through-holes 197 is reduced, the total number of the through-holes 197 in the inner upper electrode 187A is increased to maintain a predetermined total flow rate of the process gas from the process gas plenum region 188 through the inner upper electrode 187A to the plasma processing region 182. Also, in some embodiments, the upper electrodes 187A / 187B are electrically connected to a reference ground potential. However, in other embodiments, the inner upper electrode 187A and / or the outer upper electrode 187B are electrically connected to either their respective DC power source or their respective RF power source by corresponding impedance matching circuits.

[0060] Referring again to FIG. 1A, the plenum region 188 is defined by an upper member 189. One or more gas supply ports 192 are formed through the chamber 101 and the upper member 189 and are in fluid communication with the plenum region 188. The one or more gas supply ports 192 are fluidly connected (pipeds) to a process gas supply system 191. The process gas supply system 191 includes, for example, one or more process gas supply sources, one or more mass flow controllers, one or more flow control valves, and other devices, and supplies a controlled flow of one or more process gases to the plenum region 188 through the one or more gas supply ports 192, as indicated by arrow 193. In some embodiments, the process gas supply system 191 also includes one or more components for controlling the temperature of the process gas. The process gas supply system 191 is connected to the control system 120 via one or more signal conductors 194.

[0061] The processing gap (g1) is defined as the vertical (z-direction) distance measured between the top surface of the ceramic layer 110 and the bottom surface of the inner upper electrode 187A. The size of the processing gap (g1) can be adjusted by moving the cantilever arm assembly 115 in the vertical direction (z-direction). When the cantilever arm assembly 115 moves upward, the connecting outer support flange 171 eventually engages with the lower wall 185A of the C-shroud member 185. At this time, as the cantilever arm assembly 115 continues to move upward until the set of support rods 201 engages with the connecting outer support flange 171, the connecting outer support flange 171 moves along the fixed outer support flange 169, and the size of the predetermined processing gap (g1) is realized. Next, to perform this reverse movement to remove the wafer W from the chamber, the cantilever arm assembly 115 moves downward until the connecting outer support flange 171 separates from the lower wall 185A of the C-shroud member 185. FIG. 1B shows how, in some embodiments, the cantilever arm assembly 115 in the system 100 of FIG. 1A is moved downward to enable the movement of the wafer W through the door 107. In various embodiments, the size of the processing gap (g1) during the plasma processing of the wafer W is controlled in the range up to about 10 centimeters, up to about 8 centimeters, or up to about 5 centimeters. Also, in FIG. 1B, the wafer W is shown in a position lifted by the lift pins 133. Note that FIG. 1A shows the system 100 in a closed configuration where the wafer W is positioned on the ceramic layer 110 for plasma processing.

[0062] During plasma processing operations within the plasma processing system 100, one or more process gases are supplied to the plasma processing region 182 through the process gas supply system 191, the plenum region 188, and the through-port 197 within the inner upper electrode 187A. Also, RF signals are transmitted into the plasma processing region 182 by the first and second RF signal generators 147, 149, the impedance matching system 143, the RF signal supply rod 137, the RF signal supply shaft 141, the facility plate 111, the electrode 109, and also through the ceramic layer 110. The RF signals convert the process gas into plasma 180 within the plasma processing region 182. The ions and / or reactive components of the plasma interact with one or more materials on the wafer W to change the composition and / or shape of the specific materials present on the wafer W. The exhaust gas from the plasma processing region 182 is affected by the suction force applied to the exhaust port 105 as indicated by the arrow 195 and flows through the vent 186 within the C-shroud member 185 and the internal region 103 within the chamber 101 to the exhaust port 105.

[0063] In various embodiments, electrode 109 can be configured to have different diameters. However, in some embodiments, the diameter of electrode 109 is extended to increase the surface area of electrode 109 on which edge ring 167 is placed. For example, FIG. 9 shows an enlarged view of region 220 near edge ring 167 as also shown in FIG. 1A, showing electrode 109 having an extended diameter according to some embodiments. Before the extension of the diameter of electrode 109, the outer edge of electrode 109 is indicated by dashed line 222. With the outer edge of electrode 109 indicated at dashed line 222, edge ring 167 is placed on a portion of electrode 109 having a radial distance (d5) less than half of the radial distance (d7) of edge ring 167. With the extension of the diameter of electrode 109, outer edge portion 224 of electrode 109 is positioned further away towards the outer diameter of edge ring 167, and edge ring 167 is placed on a portion of electrode 109 having a radial distance (d6). In some embodiments, the radial distance (d6) is at least 1 / 2 of the radial distance (d7) of edge ring 167. In some embodiments, the radial distance (d6) is at least 3 / 4 of the radial distance (d7) of edge ring 167. In some embodiments, conductive gel 226 is disposed between the bottom of edge ring 167 and the top of electrode 109. In these embodiments, the extension of the diameter of electrode 109 increases the surface area of the conductive gel disposed between edge ring 167 and electrode 109.

[0064] Note that the combination of the connection outer support flange 171, the conductive strap 173, and the fixed outer support flange 169 is at electrically grounded reference potential, and collectively they form a ground return path for the RF signal transmitted from the electrode 109 through the ceramic layer 110 to the plasma processing region 182. The azimuthal uniformity of this ground return path around the outer periphery of the electrode 109 can affect the uniformity of the processing results on the wafer W. For example, in some embodiments, the uniformity of the etching rate across the entire wafer W can be affected by the azimuthal uniformity of the ground return path around the outer periphery of the electrode 109. Therefore, the number, configuration, and arrangement of the conductive straps 173 around the outer periphery of the electrode 109 can affect the uniformity of the processing results across the entire wafer W.

[0065] In the exemplary embodiments shown in FIGS. 1A, 1B, 4A, 4B, 5, and 6, the conductive strap 173 is shown to have an "outward" configuration, in which the conductive strap 173 bends outward away from the fixed outer support flange 169. In other embodiments, the conductive strap 173 is configured to bend inward toward the inside of the fixed outer support flange 169. FIG. 10 is an alternative to FIG. 4A and shows a conductive strap 173A configured to bend inward toward the fixed outer support flange 169, according to some embodiments. The configuration of the conductive strap 173A in FIG. 10 is referred to as an "inward" configuration. In other embodiments, the conductive strap 173B is configured to bend in an S-shape between the connection outer support flange 171 and the fixed outer support flange 169. FIG. 11 is an alternative to FIG. 4A and shows a conductive strap 173B configured to bend in an S-shape between the connection outer support flange 171 and the fixed outer support flange 169, according to some embodiments. The configuration of the conductive strap 173B in FIG. 11 is referred to as an "S-shaped" configuration.

[0066] Note that the outward, inward, and S-shaped configurations of the conductive straps 173, 173A, and 173B have different performance characteristics with respect to the ground return path for RF signals within the system 100. In particular, the impedance characteristics of the outward, inward, and S-shaped configurations of the conductive straps 173, 173A, and 173B change due to differences in the proximity between the conductive straps 173, 173A, and 173B and the outer vertical surface 169D of the vertical portion 169A of the fixed outer support flange 169, especially when the connecting outer support flange 171 moves in the vertical direction (z-direction). As the processing gap (g1) increases, the connecting outer support flange 171 rises in the z-direction relative to the fixed outer support flange 169, and in some cases, tends to reduce the curvature of the conductive straps 173, 173A, and 173B towards or away from the vertical portion 169A of the fixed outer support flange 169. Further, as the processing gap (g1) decreases, the connecting outer support flange 171 lowers in the z-direction relative to the fixed outer support flange 169, and in some cases, tends to increase the curvature of the conductive straps 173, 173A, and 173B towards or away from the vertical portion 169A of the fixed outer support flange 169. These changes in the curvature of the conductive straps 173, 173A, and 173B due to the processing gap (g1) size, along with changes in the proximity of the conductive straps 173, 173A, and 173B to the vertical portion 169A of the fixed outer support flange 169, can cause impedance changes along the RF signal ground return path formed by the conductive straps 173, 173A, and 173B.

[0067] Through the study of the outward, inward, and S-shaped configurations of the conductive straps 173, 173A, and 173B, in the outward configuration of the conductive strap 173 (as shown in FIGS. 1A, 1B, 4A, 4B, 5, and 6), 1) the uniformity of the etching rate across the entire wafer W in the radial direction is better, and 2) it is shown that higher RF power can be delivered to the plasma 180 at a higher frequency, for example, 60 MHz. Also, through the study of the outward and inward configurations of the conductive straps 173 and 173A, in the inward configuration of the conductive strap 173A, it is shown that larger amplitudes of higher-order harmonics (4th, 5th, 6th, 7th, 10th, 11th, 12th harmonics) occur in the RF signal transmitted from the impedance matching system 143 to the RF signal supply rod 137. Therefore, it is beneficial to use the outward configuration of the conductive strap 173 to avoid the amplification of these higher-order harmonics in the RF signal delivered to the plasma. In some embodiments, all of the conductive straps 173 have an outward configuration. However, in some embodiments, a subset of the conductive straps 173 has an outward configuration, and one or more other subsets of the conductive straps 173 have another shape, such as an inward configuration or an S-shaped configuration. In some of these embodiments, the conductive straps 173 having an outward configuration are substantially uniformly distributed around the connecting outer support flange 171 and the fixed outer support flange 169. Also, in some of these embodiments, the subset of the conductive straps 173 having an outward configuration is the subset that makes up the majority of the total number of conductive straps 173.

[0068] In an exemplary embodiment, the plasma processing system 100 includes an electrode 109, a ceramic layer 110, RF signal generators 147 / 149, a fixed outer support flange 169, a connecting outer support flange 171, and a plurality of conductive straps 173. The electrode 109 has a substantially upper cylindrical shape defined by a top surface, a bottom surface, and an outer surface. The top surface of the electrode 109 corresponds to a reference horizontal plane (x-y plane), and the reference vertical direction (z direction) is perpendicular to the reference horizontal plane. A ceramic layer 110 is formed on the top surface of the electrode 109. The ceramic layer 110 is configured to receive and support a wafer W. The RF signal generators 147, 149 are electrically connected to the electrode 109 via an impedance matching system 143. The RF signal generators 147, 149 are configured to generate an RF signal and supply it to the electrode 109.

[0069] The fixed outer support flange 169 is formed to surround the outer surface of the electrode 109. The fixed outer support flange 169 has a fixed spatial relationship with respect to the electrode 109. The fixed outer support flange 169 has a vertical portion 169A and a horizontal portion 169B extending radially outward from the lower end of the vertical portion 169A. The fixed outer support flange 169 is electrically connected to a reference ground potential, for example, by a cantilever arm assembly 115. The connecting outer support flange 171 is formed to surround the fixed outer support flange 169. The connecting outer support flange 171 has a vertical portion 171A and a horizontal portion 171B extending radially outward from the lower end of the vertical portion 171A. The vertical portion 171A of the connecting outer support flange 171 is concentrically disposed outside at least a part of the vertical portion 169A of the fixed outer support flange 169. The connecting outer support flange 171 is spaced apart from the fixed outer support flange 169 so as to be movable in a direction perpendicular to the fixed outer support flange 169.

[0070] Each of the plurality of conductive straps 173 has a first end connected to the horizontal portion 171B of the connecting outer support flange 171 and a second end connected to the horizontal portion 169B of the fixed outer support flange 169. Each of the plurality of conductive straps 173 is bent outward in a direction away from the vertical portion 169A of the fixed outer support flange 169. In some embodiments, the plurality of conductive straps 173 are arranged in a substantially equally spaced configuration around both the connecting outer support flange 171 and the fixed outer support flange 169. The plurality of conductive straps 173 are configured to bend as the connecting outer support flange 171 moves relative to the fixed outer support flange 169. Each of the plurality of conductive straps 173 has a bendable length between the first end connected to the connecting outer support flange 171 and the second end connected to the fixed outer support flange 169. As the plurality of conductive straps 173 bend outward, the entire bendable length of each of the plurality of conductive straps 173 is disposed outside the connecting outer support flange 171 and / or the fixed outer support flange 169. In some embodiments, the first end of each of the plurality of conductive straps 173 is connected to the lower surface 171D of the horizontal portion 171B of the connecting outer support flange 171 (see FIG. 4A). In some embodiments, the first end of each of the plurality of conductive straps 173 is connected to the upper surface 171F of the horizontal portion 171B of the connecting outer support flange 171 (see FIG. 4B). In some embodiments, the second end of each of the plurality of conductive straps 173 is connected to the upper surface 169F of the horizontal portion 169B of the fixed outer support flange 169 (see FIGS. 4A and 4B).

[0071] In some embodiments, the clamping ring 177 (first clamping ring) is connected to the horizontal portion 171B of the connecting outer support flange 171. The first ends of the plurality of conductive straps 173 are disposed between the clamping ring 177 and the horizontal portion 171B of the connecting outer support flange 171. The clamping ring 177 secures the physical and electrical connection of the plurality of conductive straps 173 to the horizontal portion 171B of the connecting outer support flange 171. Also, the clamping ring 175 (second clamping ring) is connected to the horizontal portion 169B of the fixed outer support flange 169. The second ends of the plurality of conductive straps 173 are disposed between the clamping ring 175 and the horizontal portion 169B of the fixed outer support flange 169. The clamping ring 175 secures the physical and electrical connection of the plurality of conductive straps 173 to the horizontal portion 169B of the fixed outer support flange 169. In some embodiments, the clamping ring 177 is bolted to the horizontal portion 171B of the connecting outer support flange 171, and the clamping ring 175 is bolted to the horizontal portion 169B of the fixed outer support flange 169. Also, in some embodiments, the bolts used to bolt the clamping ring 177 to the horizontal portion 171B of the connecting outer support flange 171 are disposed between the first ends of the conductive straps 173. Similarly, in some embodiments, the bolts used to bolt the clamping ring 175 to the horizontal portion 169B of the fixed outer support flange 169 are disposed between the second ends of the conductive straps 173.

[0072] In some embodiments, each of the connecting outer support flange 171, the fixed outer support flange 169, the clamping ring 177, and the clamping ring 175 is formed of aluminum. In some embodiments, each of the connecting outer support flange 171, the fixed outer support flange 169, the clamping ring 177, and the clamping ring 175 is formed of anodized aluminum. In some embodiments, each of the plurality of conductive straps 173 is formed of stainless steel. In some embodiments, each of the plurality of conductive straps 173 is formed of copper. In some embodiments, the number of the plurality of conductive straps 173 is in the range of about 6 to about 80.

[0073] In some embodiments, each of the plurality of conductive straps 173 has a rectangular prism shape as described with respect to FIG. 7. Also, in some embodiments, there is an azimuthal interval between adjacent ones of the plurality of conductive straps 173 at the outer periphery of the horizontal portion 171B of the connecting outer support flange 171 as described with respect to FIG. 5. The azimuthal interval is measured with respect to the central axis of the connecting outer support flange 171 extending in the z direction.

[0074] In some embodiments, the C-shroud member 185 is disposed above the electrode 109. The seal 179 is disposed at the upper end 171E of the vertical portion 171A of the connecting outer support flange 171. The seal 179 is configured to engage the C-shroud member 185 when the connecting outer support flange 171 moves upward to reach the C-shroud member 185. In some embodiments, the seal 179 is conductive and provides conductivity between the C-shroud member 185 and the connecting outer support flange 171.

[0075] In some embodiments, a ceramic structure such as the ceramic support 113 is disposed between the electrode 109 and the fixed outer support flange 169. The ceramic structure is formed to surround the outer surface of the electrode 109. Also, in some embodiments, a quartz structure such as the first quartz ring 163 is disposed between the ceramic structure and the fixed outer support flange 169. The quartz structure is formed to surround the vertical portion of the ceramic structure. Also, in some embodiments, the edge ring 167 is disposed between the connecting outer support flange 171 and the ceramic layer 110. In some embodiments, a quartz ring such as the second quartz ring 165 is disposed between the edge ring 167 and the connecting outer support flange 171.

[0076] In an exemplary embodiment, a ground return assembly for the plasma processing system 100 is disclosed. The ground return assembly includes a fixed outer support flange 169, a connecting outer support flange 171, and a plurality of conductive straps 173. The fixed outer support flange 169 is formed to surround the electrode 109 within the plasma processing system 100 and has a fixed spatial relationship with respect to the electrode 109. The fixed outer support flange 169 has a vertical portion 169A and a horizontal portion 169B extending radially outward from the lower end of the vertical portion 169A. The connecting outer support flange 171 is formed to surround the fixed outer support flange 169. The connecting outer support flange 171 has a vertical portion 171A and a horizontal portion 171B extending radially outward from the lower end of the vertical portion 171A. The vertical portion 171A of the connecting outer support flange 171 is concentrically disposed outside at least a portion of the vertical portion 169A of the fixed outer support flange 169. The connecting outer support flange 171 is spaced apart from the fixed outer support flange 169 so as to be movable along the vertical portion 169A of the fixed outer support flange 169. Each of the plurality of conductive straps 173 has a first end connected to the connecting outer support flange 171 and a second end connected to the fixed outer support flange 169. Each of the plurality of conductive straps 173 is bent outward in a direction away from the vertical portion 169A of the fixed outer support flange 169.

[0077] In an exemplary embodiment, the plasma processing system 100 includes an electrode 109, a ceramic layer 110, a facility plate 111, an RF signal supply shaft 141, an RF signal supply rod 137, RF signal generators 147, 149, an impedance matching system 143, and a tube 139. The electrode 109 is formed of a conductive material. The electrode 109 has a substantially upper cylindrical shape defined by a top surface, a bottom surface, and an outer surface. The ceramic layer 110 is formed on the top surface of the electrode 109 and is configured to receive and support the wafer W. The facility plate 111 is formed of a conductive material. The bottom surface of the electrode 109 is physically and electrically connected to the top surface of the facility plate 111. The RF signal supply shaft 141 is formed of a conductive material. The upper end of the RF signal supply shaft 141 is physically and electrically connected to the bottom surface of the facility plate 111. The RF signal supply rod 137 is formed of a conductive material. The lower end of the RF signal supply shaft 141 is physically and electrically connected to the sending end of the RF signal supply rod 137. The RF signal generators 147 and / or 149 are electrically connected to the supply end of the RF signal supply rod 137 via the impedance matching system 143. The tube 139 is disposed around the RF signal supply rod 137. The tube 139 is formed of a conductive material. The tube 139 has an inner wall separated from the RF signal supply rod 137 by air along the entire length of the tube 139.

[0078] In some embodiments, the physical and electrical connection between the RF signal supply rod 137 and the RF signal supply shaft 141 is separated from surrounding conductive materials by air. In some embodiments, the physical connection between the supply end of the RF signal supply rod 137 and the impedance matching system 143, the physical connection between the transmission end of the RF signal supply rod 137 and the lower end of the RF signal supply shaft 141, and the physical connection between the upper end of the RF signal supply shaft 141 and the bottom surface of the facility plate 111 collectively maintain the physical dimensions of the gap between the RF signal supply rod 137 and the inner wall of the tube 139 along the entire length of the tube 139. In some embodiments, the tube 139 forms part of a ground potential feedback path for the RF signal transmitted through the RF signal supply rod 137. Considering that the top surface of the electrode 109 corresponds to the reference horizontal plane (x-y plane) and the reference vertical direction (z direction) g extends perpendicular to the reference horizontal plane, in some embodiments, the RF signal supply rod 137 extends substantially parallel and linearly to the reference horizontal plane, and the RF signal supply shaft 141 has a central axis that is substantially parallel to the reference vertical direction.

[0079] In some embodiments, the RF signal supply rod 137 is formed of copper, aluminum, or anodized aluminum. In some embodiments, the RF signal supply rod 137 is a solid rod. In some embodiments, the RF signal supply rod 137 is a tube. In some embodiments, the RF signal supply rod 137 has an outer diameter in the range of about 0.75 inches to about 2 inches. In some embodiments, the tube 139 has an inner diameter in the range of about 1.5 inches to about 6 inches. In some embodiments, the difference between the inner diameter of the tube 139 and the outer diameter of the RF signal supply rod 137 is in the range of about 0.25 inches to about 4 inches.

[0080] In some embodiments, the tube 139 is a first tube, and the plasma processing system 100 includes a second tube 139A disposed around at least a lower portion of the RF signal supply shaft 141. The first tube 139 is connected to the second tube 139A, and the internal volume of the first tube 139 is open to the internal volume of the second tube 139A (see FIG. 1A). The internal volumes of the first tube 139 and the second tube 139A form a continuous air region around both the RF signal supply rod 137 and the RF signal supply shaft 141 at a position 140 (see FIG. 1A) where the lower end of the RF signal supply shaft 141 is physically and electrically connected to the delivery end of the RF signal supply rod 137.

[0081] In an exemplary embodiment, an RF signal supply structure for the plasma processing system 100 is disclosed. The RF signal supply structure includes an RF signal supply rod 137 and a tube 139. The RF signal supply rod 137 is formed of a conductive material and includes a supply end and a delivery end. The supply end is configured for connection to an impedance matching system 143 disposed between the RF signal supply rod 137 and the RF signal generators 147, 149. The tube 139 is disposed near the RF signal supply rod 137. The tube 139 is formed of a conductive material and has an inner wall separated from the RF signal supply rod 137 by air along the entire length of the tube 139. In some embodiments, the tube 139 extends from a position proximate the impedance matching system 143 to a position proximate the delivery end of the RF signal supply rod 137. In some embodiments, the tube 139 forms part of a ground potential feedback path for the RF signal transmitted through the RF signal supply rod 137.

[0082] FIG. 12 shows an exemplary schematic diagram of the control system 120 of FIG. 1A according to some embodiments. In some embodiments, the control system 120 is configured as a process controller for controlling semiconductor manufacturing processes executed in the plasma processing system 100. In various embodiments, the control system 120 includes a processor 1201, a storage hardware unit (HU) 1203 (e.g., memory), an input HU 1205, an output HU 1207, an input / output (I / O) interface 1209, an I / O interface 1211, a network interface controller (NIC) 1213, and a data communication bus 1215. The processor 1201, the storage HU 1203, the input HU 1205, the output HU 1207, the I / O interface 1209, the I / O interface 1211, and the NIC 1213 communicate data with each other via the data communication bus 1215. The input HU 1205 is configured to receive data communication from a number of external devices. Examples of the input HU 1205 include a data acquisition system, a data acquisition card, etc. The output HU 1207 is configured to transmit data to a number of external devices. An example of the output HU 1207 includes a device controller. Examples of the NIC 1213 include a network interface card, a network adapter, etc. Each of the I / O interfaces 1209 and 1211 is defined to provide compatibility between different hardware units coupled to the I / O interface. For example, the I / O interface 1209 may be defined to convert a signal received from the input HU 1205 into a form, amplitude, and / or speed compatible with the data communication bus 1215. Also, the I / O interface 1207 may be defined to convert a signal received from the data communication bus 1215 into a form, amplitude, and / or speed compatible with the output HU 1207.Although various operations are described herein as being performed by the processor 1201 of the control system 120, in some embodiments, the various operations may be performed by multiple processors of the control system 120 and / or by multiple processors of multiple computing systems that communicate with the control system 120 via data communication.

[0083] In some embodiments, control system 120 is used to control devices within various wafer manufacturing systems, based in part on sensed values. For example, control system 120 can control one or more of valve 1217, filter heater 1219, wafer support structure heater 1221, pump 1223, and other devices 1225, based on sensed values and other control parameters. Valve 1217 can include valves associated with the control of back gas supply system 129, process gas supply system 191, and temperature control fluid circulation system 125. Control system 120 receives sensed values from, for example, pressure gauge 1227, flow meter 1229, temperature sensor 1231, and / or other sensors 1233 such as voltage sensors, current sensors, etc. Control system 120 can also be used to control process conditions within plasma processing system 100 while performing plasma processing operations on wafer W. For example, control system 120 can control the type and amount of process gas supplied from process gas supply system 191 to plasma processing region 182. Also, control system 120 can control the operation of first RF signal generator 147, second RF signal generator 149, and impedance matching system 143. Also, control system 120 can control the operation of DC power supply 117 for clamp electrode 112. Control system 120 can also control the operation of lift device 133 for lift pin 132 and the operation of door 107. Control system 120 also controls the operation of back gas supply system 129 and temperature control fluid circulation system 125. Control system 120 also controls the vertical movement of cantilever arm assembly 115. Control system 120 also controls the operation of throttle member 196 and the pump that controls suction at exhaust port 105. Note that control system 120 is equipped to programmatically and / or manually control any function within plasma processing system 100.

[0084] In some embodiments, the control system 120 is configured to execute a computer program that includes a set of instructions for controlling process timing, process gas delivery system temperature, pressure differential, valve position, process gas mixing, process gas flow rate, backside cooling gas flow rate, chamber pressure, chamber temperature, wafer support structure temperature (wafer temperature), RF power level, RF frequency, RF pulse, settings of the impedance matching system 143, position of the cantilever arm assembly, bias power, and other parameters of a particular process. In some embodiments, other computer programs stored in a memory device associated with the control system 120 may be used. In some embodiments, there is a user interface associated with the control system 120. Examples of the user interface include a display 1235 (e.g., a display screen and / or graphical software representation of the device, and / or process conditions), and user input devices 1237 such as a pointing device, keyboard, touch screen, microphone, and the like.

[0085] The software that instructs the operation of the control system 120 can be designed or configured in many different ways. A computer program that instructs the operation of the control system 120 to execute various wafer manufacturing processes in a process sequence can be written in any conventional computer-readable programming language, such as assembly language, C, C++, Pascal, Fortran, etc. The compiled object code or script is executed by the processor 1201 to perform the tasks identified within the program. The control system 120 can be programmed to control various process control parameters related to process conditions, such as filter pressure difference, process gas composition and flow rate, backside cooling gas composition and flow rate, temperature, pressure, plasma conditions such as RF power level and RF frequency, bias voltage, cooling gas / fluid pressure, chamber wall temperature, etc. Examples of sensors that can be monitored during the wafer manufacturing process include, but are not limited to, a mass flow control module, a pressure sensor such as the pressure gauge 1227, and a temperature sensor 1231. Appropriate feedback and control algorithms, programmed appropriately, can be used with the data from these sensors to control / regulate one or more process control parameters to maintain the desired process conditions.

[0086] In some implementations, control system 120 is part of a broader manufacturing control system. Such a manufacturing control system may comprise semiconductor processing equipment including processing tools, chambers, and / or platforms for wafer processing, and / or specific processing components such as wafer pedestals, gas flow systems, etc. These manufacturing control systems may be integrated with electronics for controlling their operation before, during, and after wafer processing. Control system 120 is capable of controlling various components or sub-parts of the manufacturing control system. Control system 120 may be programmed to control any of the processes disclosed herein, including delivery of process gases, delivery of backside cooling gases, temperature setting (e.g., heating and / or cooling), pressure setting, vacuum setting, power setting, radio frequency (RF) generator setting, RF matching circuit setting, frequency setting, flow rate setting, fluid delivery setting, position and motion setting, and wafer transfer into and out of tools and other transfer tools and / or load locks connected or interfaced to a particular system, according to wafer processing requirements.

[0087] Generally, control system 120 can be defined as an electronic device having various integrated circuits, logic, memory, and / or software, which receives and issues commands, controls operations, enables wafer processing operations, enables endpoint measurements, etc. The integrated circuits may include a chip in the form of firmware storing program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuit (ASIC), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). The program instructions may be instructions transmitted to control system 120 in the form of various individual settings (or program files) that define operating parameters for performing a specific process on wafer W within system 100. In some embodiments, the operating parameters may be part of a recipe defined by a process engineer to achieve one or more processing steps during the manufacture of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0088] In some implementations, the control system 120 may be integrated or coupled with the plasma processing system 100, be part of a computer network-connected to the system 100, or be combined, and may be in a combined form. For example, the control system 120 may be within all or part of the "cloud" of a fab host computer system that enables remote access to wafer processing. The computer may enable remote access to the system 100, monitor the current progress of manufacturing operations, investigate the history of past manufacturing operations, investigate trends or performance metrics from multiple manufacturing operations, change the parameters of the current process, set processing steps to follow the current process, or start a new process. In some examples, a remote computer (e.g., a server) can provide a process recipe to the system 100 over a network, which may include a local network or the Internet.

[0089] The remote computer may include a user interface that enables the input or programming of parameters and / or settings, and these parameters and / or settings are then transmitted from the remote computer to the system 100. In some examples, the control system 120 receives instructions in the form of data, and the instructions specify the parameters for each of the processing steps to be performed during one or more operations. Note that the parameters may be specific to the type of process performed within the plasma processing system 100. Thus, as described above, the control system 120 may be distributed, for example, using one or more discrete controllers, and the one or more discrete controllers are collectively network-connected and operate with a common purpose such as the processing and control described herein. An example of a distributed controller for such a purpose is one or more integrated circuits of the plasma processing system 100 that communicate with one or more integrated circuits located remotely (e.g., at the platform level or as part of a remote computer), and are combined to control the processes executed on the plasma processing system 100.

[0090] Although not limited, examples of systems with which control system 120 may interface include a plasma etching chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etching chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etching (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing system that may be associated with or used in the fabrication and / or manufacture of semiconductor wafers. As described above, depending on one or more process steps performed by the tool, control system 120 may communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, proximity tools, neighboring tools, tools disposed throughout the factory, a host computer, another controller, or a tool used in transporting a wafer container to or from a tool location and / or load port in a semiconductor manufacturing facility.

[0091] The embodiments described in this specification can be implemented with various computer system configurations, including handheld hardware units, microprocessor systems, microprocessor-based or program-controlled household appliances, minicomputers, mainframe computers, and the like. Further, the embodiments described in this specification can be implemented with a distributed computing environment in which tasks are executed by remote processing hardware units connected via a network. Note that the embodiments described in this specification, particularly those related to the control system 120, can use operations performed by various computers based on data stored in the computer system. These operations require physical manipulation of physical quantities. Any operation described in this specification that is part of an embodiment is a useful mechanical operation. Also, the embodiments relate to hardware units or devices for performing these operations. The device can be specially configured for a special-purpose computer. When defined as a special-purpose computer, it can perform other processes, program executions, or routines that are not part of the special purpose while enabling operations for that special purpose. In some embodiments, the operations can be processed by a general-purpose computer selectively activated or configured by one or more computer programs stored in a computer memory, cache, or obtained from a network. When data is obtained from a network, the data can be processed by other computers on the network, such as a cloud of computing resources.

[0092] The various embodiments described herein can be implemented via process control instructions instantiated as computer-readable code on a non-transitory computer-readable medium. A non-transitory computer-readable medium is any data storage hardware unit that stores data and then can be read by a computer system. Examples of non-transitory computer-readable media include hard disks, network attached storage (NAS), ROM, RAM, compact disc ROM (CD-ROM), recordable CD (CD-R), rewritable CD (CD-RW), magnetic tape, and other optical and non-optical data storage hardware units. The non-transitory computer-readable media can include computer-readable tangible media distributed over a network-coupled computer system and perform the storage and execution of the computer-readable code in a distributed manner.

[0093] The foregoing disclosure, for a clearer understanding, includes detailed descriptions, but it is clear that within the scope of the appended claims, certain changes and modifications are allowed. For example, one or more features from any of the embodiments disclosed herein can be combined with one or more features from any of the other embodiments disclosed herein. Therefore, it should be recognized that this embodiment is merely illustrative and not restrictive, and also that the claims are not limited to the details described herein and can be modified within the scope of the described embodiments and equivalent parts.

Claims

1. 1. A plasma processing system comprising: an electrode having a substantially cylindrical shape defined by a top surface, a bottom surface, and an exterior surface; a ceramic layer formed on the top surface of the electrode, the ceramic layer being configured to receive and support a semiconductor wafer; an RF signal generator electrically connected to the electrode through an impedance matching system and configured to generate and supply an RF signal to the electrode; a fixed outer support flange formed around the outer surface of the electrode, in a fixed spatial relationship with respect to the electrode, having a vertical portion and a horizontal portion extending radially outward from a lower end of the vertical portion, the fixed outer support flange being electrically connected to a reference ground potential; a connecting outer support flange formed to surround the fixed outer support flange and having a vertical portion concentrically disposed outside the vertical portion of the fixed outer support flange and a horizontal portion extending radially outward from a lower end of the vertical portion, the connecting outer support flange being disposed spaced apart from the fixed outer support flange so as to be movable vertically relative to the fixed outer support flange; a plurality of conductive straps, each having a first end connected to the horizontal portion of the interlocking outer support flange and a second end connected to the horizontal portion of the fixed outer support flange; A plasma processing system comprising:

2. 10. The plasma processing system of claim 1 , Each of the plurality of conductive straps bends outwardly away from the vertical portion of the stationary outer support flange.

3. 10. The plasma processing system of claim 1 , The plasma processing system, wherein the plurality of conductive straps are disposed in a substantially equally spaced configuration around a circumference of both the connecting outer support flange and the fixed outer support flange.

4. 10. The plasma processing system of claim 1 , The plasma processing system, wherein the plurality of conductive straps are configured to flex with movement of the interlocking outer support flange relative to the fixed outer support flange.

5. 10. The plasma processing system of claim 1 , 11. The plasma processing system of claim 10, wherein each of the plurality of conductive straps has a bendable length extending between the first end and the second end, and wherein an entirety of the bendable length of each of the plurality of conductive straps is disposed outside of the connecting outer support flange and / or the fixed outer support flange.

6. 10. The plasma processing system of claim 1 , The first end of each of the plurality of conductive straps is connected to a lower surface of the horizontal portion of the interlocking outer support flange.

7. 10. The plasma processing system of claim 1 , The first end of each of the plurality of conductive straps is connected to an upper surface of the horizontal portion of the interlocking outer support flange.

8. 10. The plasma processing system of claim 1 , The second end of each of the plurality of conductive straps is connected to an upper surface of the horizontal portion of the stationary outer support flange.

9. 10. The plasma processing system of claim 1 , a first clamp ring connected to the horizontal portion of the interlocking outer support flange, the first ends of the plurality of conductive straps being disposed between the first clamp ring and the horizontal portion of the interlocking outer support flange, the first clamp ring securing the plurality of conductive straps in physical and electrical connection with the horizontal portion of the interlocking outer support flange; 11. The plasma processing system of claim 10, further comprising: a second clamp ring connected to the horizontal portion of the fixed outer support flange, wherein the second ends of the plurality of conductive straps are disposed between the second clamp ring and the horizontal portion of the fixed outer support flange, the second clamp ring securing the plurality of conductive straps in physical and electrical connection with the horizontal portion of the fixed outer support flange.

10. 10. The plasma processing system of claim 9, further comprising: The plasma processing system, wherein the first clamp ring is bolted to the horizontal portion of the interlocking outer support flange and the second clamp ring is bolted to the horizontal portion of the fixed outer support flange.

11. 11. The plasma processing system of claim 10, a bolt used to bolt the first clamp ring to the horizontal portion of the connecting outer support flange is disposed between the first ends of the conductive straps, and a bolt used to bolt the second clamp ring to the horizontal portion of the fixed outer support flange is disposed between the second ends of the conductive straps.

12. 10. The plasma processing system of claim 9, further comprising: The plasma processing system, wherein each of the interlocking outer support flange, the fixed outer support flange, the first clamp ring, and the second clamp ring are formed from aluminum or anodized aluminum.

13. 10. The plasma processing system of claim 1 , The plasma processing system, wherein each of the plurality of conductive straps is formed from stainless steel.

14. 10. The plasma processing system of claim 1 , The plasma processing system, wherein a number of the plurality of conductive straps is in a range from about 6 to about 80.

15. 10. The plasma processing system of claim 1 , The plasma processing system, wherein each of the plurality of conductive straps has a rectangular prism shape defined by a length, a width, and a thickness.

16. 10. The plasma processing system of claim 1 , a C-shroud member disposed above the electrode; a seal disposed at an upper end of the vertical portion of the connecting outer support flange and configured to engage the C-shroud member when the connecting outer support flange moves upwardly into the C-shroud member; The plasma processing system further comprises:

17. 17. The plasma processing system of claim 16, wherein said seal is electrically conductive and provides electrical conductivity between said C-shroud member and said mating outer support flange.

18. 10. The plasma processing system of claim 1 , The plasma processing system further comprising a ceramic structure formed and positioned between the electrode and the fixed outer support flange so as to surround the outer surface of the electrode.

19. 20. The plasma processing system of claim 18, further comprising: The plasma processing system further comprising a quartz structure formed and positioned between the ceramic structure and the fixed outer support flange so as to surround a vertical portion of the ceramic structure.

20. 10. The plasma processing system of claim 1 , The plasma processing system further comprises an edge ring disposed between the connecting outer support flange and the ceramic layer.

21. 21. The plasma processing system of claim 20, further comprising: The plasma processing system further comprising a quartz ring disposed between the edge ring and the mating outer support flange.

22. 1. A ground return assembly for a plasma processing system, comprising: a fixed outer support flange configured to surround an electrode within the plasma processing system and having a fixed spatial relationship to the electrode, the fixed outer support flange having a vertical portion and a horizontal portion extending radially outward from a lower end of the vertical portion; a connecting outer support flange formed to surround the fixed outer support flange, the connecting outer support flange having a vertical portion concentrically disposed outside the vertical portion of the fixed outer support flange and a horizontal portion extending radially outward from a lower end of the vertical portion, the connecting outer support flange being disposed at a distance from the fixed outer support flange so as to be movable along the vertical portion of the fixed outer support flange; a plurality of conductive straps, each having a first end connected to the interlocking outer support flange and a second end connected to the fixed outer support flange; A ground return assembly for a plasma processing system comprising:

23. 23. The ground return assembly for a plasma processing system of claim 22, comprising: A ground return assembly for a plasma processing system, wherein each of the plurality of conductive straps bends outwardly away from the vertical portion of the fixed outer support flange.

24. 23. The ground return assembly for a plasma processing system of claim 22, comprising: A ground return assembly for a plasma processing system, wherein the plurality of conductive straps are disposed in a substantially equally spaced configuration around a circumference of both the connecting outer support flange and the fixed outer support flange.

25. 23. The ground return assembly for a plasma processing system of claim 22, comprising: A ground return assembly for a plasma processing system, wherein the plurality of conductive straps are configured to flex with movement of the interlocking outer support flange relative to the fixed outer support flange.

26. 23. The ground return assembly for a plasma processing system of claim 22, comprising:

11. A ground return assembly for a plasma processing system, wherein each of the plurality of conductive straps has a bendable length extending between the first end and the second end, and wherein an entirety of the bendable length of each of the plurality of conductive straps is disposed outside of the connecting outer support flange and / or the fixed outer support flange.

27. 23. The ground return assembly for a plasma processing system of claim 22, comprising: A ground return assembly for a plasma processing system, wherein the first end of each of the plurality of conductive straps is connected to a lower surface of the horizontal portion of the interlocking outer support flange.

28. 23. The ground return assembly for a plasma processing system of claim 22, comprising: A ground return assembly for a plasma processing system, wherein the first end of each of the plurality of conductive straps is connected to an upper surface of the horizontal portion of the interlocking outer support flange.

29. 23. The ground return assembly for a plasma processing system of claim 22, comprising: A ground return assembly for a plasma processing system, wherein the second end of each of the plurality of conductive straps is connected to an upper surface of the horizontal portion of the fixed outer support flange.

30. 23. The ground return assembly for a plasma processing system of claim 22, comprising: a first clamp ring connected to the horizontal portion of the interlocking outer support flange, the first ends of the plurality of conductive straps being disposed between the first clamp ring and the horizontal portion of the interlocking outer support flange, the first clamp ring securing the plurality of conductive straps in physical and electrical connection with the horizontal portion of the interlocking outer support flange; 11. A ground return assembly for a plasma processing system, further comprising: a second clamp ring connected to the horizontal portion of the fixed outer support flange, the second ends of the plurality of conductive straps being disposed between the second clamp ring and the horizontal portion of the fixed outer support flange, the second clamp ring securing the plurality of conductive straps in physical and electrical connection with the horizontal portion of the fixed outer support flange.

31. 31. The ground return assembly for a plasma processing system of claim 30, comprising: a first clamp ring bolted to the horizontal portion of the interlocking outer support flange and a second clamp ring bolted to the horizontal portion of the fixed outer support flange.

32. 32. The ground return assembly for a plasma processing system of claim 31, comprising: a bolt used to bolt the first clamp ring to the horizontal portion of the connecting outer support flange is disposed between the first ends of the conductive straps, and a bolt used to bolt the second clamp ring to the horizontal portion of the fixed outer support flange is disposed between the second ends of the conductive straps.

33. 31. The ground return assembly for a plasma processing system of claim 30, comprising: A ground return assembly for a plasma processing system, wherein each of the interlocking outer support flange, the fixed outer support flange, the first clamp ring, and the second clamp ring are formed from aluminum.

34. 23. The ground return assembly for a plasma processing system of claim 22, comprising: A ground return assembly for a plasma processing system, wherein each of the plurality of conductive straps is formed from stainless steel.

35. 23. The ground return assembly for a plasma processing system of claim 22, comprising: The ground return assembly for a plasma processing system, wherein a number of the plurality of conductive straps is in a range from about 6 to about 80.

36. 23. The ground return assembly for a plasma processing system of claim 22, comprising: A ground return assembly for a plasma processing system, wherein each of the plurality of conductive straps has a rectangular prism shape defined by a length, a width, and a thickness.

37. 23. The ground return assembly for a plasma processing system of claim 22, comprising: A ground return assembly for a plasma processing system, wherein an upper end of the vertical portion of the interlocking outer support flange is configured to receive a conductive seal.

38. 1. A plasma processing system comprising: an electrode formed of a conductive material having a substantially cylindrical shape defined by a top surface, a bottom surface, and an exterior surface; a ceramic layer formed on the top surface of the electrode, the ceramic layer being configured to receive and support a semiconductor wafer; a facility plate formed of a conductive material and having a top surface to which the bottom surfaces of the electrodes are physically and electrically connected; an RF signal feed shaft formed of a conductive material and having an upper end physically and electrically connected to a bottom surface of the facility plate; an RF signal supply rod formed of a conductive material and having a transmission end physically and electrically connected to a lower end of the RF signal supply shaft; an RF signal generator electrically connected to the supply end of the RF signal supply rod through an impedance matching system; a tube disposed about said RF signal feed rod, said tube having an inner wall formed of a conductive material and separated from said RF signal feed rod by air along its entire length; A plasma processing system comprising:

39. 40. The plasma processing system of claim 38, further comprising: A plasma processing system, wherein the physical and electrical connection between the RF signal supply rod and the RF signal supply shaft is separated from surrounding conductive material by air.

40. 40. The plasma processing system of claim 38, further comprising: A plasma processing system wherein the physical connection between the supply end of the RF signal supply rod and the impedance matching system, the physical connection between the send end of the RF signal supply rod and the lower end of the RF signal supply shaft, and the physical connection between the upper end of the RF signal supply shaft and the bottom surface of the facility plate collectively maintain the physical dimension of the gap between the RF signal supply rod and the inner wall of the tube along the entire length of the tube.

41. 40. The plasma processing system of claim 38, further comprising: The tube forms part of a ground potential return path for an RF signal transmitted through the RF signal supply rod.

42. 40. The plasma processing system of claim 38, further comprising: a top surface of the electrode corresponding to a reference horizontal plane, a reference vertical direction extending perpendicular to the reference horizontal plane, the RF signal supply rod extending in a linear direction substantially parallel to the reference horizontal plane, and the RF signal supply shaft having a central axis substantially parallel to the reference vertical direction.

43. 40. The plasma processing system of claim 38, further comprising: The plasma processing system, wherein the RF signal supply rod is made of copper, aluminum, or anodized aluminum.

44. 40. The plasma processing system of claim 38, further comprising: The plasma processing system, wherein the RF signal supply rod is a solid rod.

45. 40. The plasma processing system of claim 38, further comprising: The plasma processing system, wherein the RF signal supply rod is a tube.

46. 40. The plasma processing system of claim 38, further comprising: the tube is a first tube, and the plasma processing system includes a second tube disposed around at least a lower portion of the RF signal supply shaft, the first tube being connected to the second tube such that an internal volume of the first tube is open to an internal volume of the second tube, and the internal volumes of the first tube and the second tube form a continuous air region around both the RF signal supply rod and the RF signal supply shaft at a location where the lower end of the RF signal supply shaft is physically and electrically connected to the delivery end of the RF signal supply rod.

47. 1. An RF signal supply structure for a plasma processing system, comprising: an RF signal feed rod formed of a conductive material and having a feed end and a delivery end, the feed end configured for connection to an impedance matching system disposed between the RF signal feed rod and an RF signal generator; a tube disposed about said RF signal feed rod, said tube having an inner wall formed of a conductive material and separated from said RF signal feed rod by air along its entire length; An RF signal supply structure for a plasma processing system comprising:

48. 48. An RF signal supply structure for a plasma processing system according to claim 47, comprising: The tube extends from a location adjacent to the impedance match system to a location adjacent to the delivery end of the RF signal delivery rod.

49. 48. An RF signal supply structure for a plasma processing system according to claim 47, comprising: The tube forms part of a ground potential return path for an RF signal transmitted through the RF signal supply rod.

50. 48. An RF signal supply structure for a plasma processing system according to claim 47, comprising: The RF signal supply structure for a plasma processing system further comprises an RF signal supply shaft having a lower end physically and electrically connected to the delivery end of the RF signal supply rod.

51. 51. An RF signal supply structure for a plasma processing system as recited in claim 50, comprising: an RF signal supply structure for a plasma processing system, wherein the tube is a first tube, and the plasma processing system includes a second tube disposed around at least a lower portion of the RF signal supply shaft, the first tube being connected to the second tube such that an internal volume of the first tube is open to an internal volume of the second tube, and the internal volumes of the first tube and the second tube form a continuous air region near both the RF signal supply rod and the RF signal supply shaft at a location where the lower end of the RF signal supply shaft is physically and electrically connected to the delivery end of the RF signal supply rod.

52. 48. An RF signal supply structure for a plasma processing system according to claim 47, comprising: The RF signal supply structure for a plasma processing system, wherein the RF signal supply rod is made of copper, aluminum, or anodized aluminum.

53. 48. An RF signal supply structure for a plasma processing system according to claim 47, comprising: The RF signal supply structure for a plasma processing system, wherein the RF signal supply rod is a solid rod.

54. 48. An RF signal supply structure for a plasma processing system according to claim 47, comprising: The RF signal supply structure for a plasma processing system, wherein the RF signal supply rod is a tube.

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