Adjustable extended electrode for edge uniformity control

Abstract

An adjustable extension electrode for edge uniformity control is disclosed. Embodiments described herein generally relate to a substrate processing apparatus. In one embodiment, a process kit for a substrate processing chamber is disclosed herein. The process kit includes: a first ring having a top surface and a bottom surface; an adjustable tuning ring having a top surface and a bottom surface; and an actuation mechanism. The bottom surface is supported by a substrate support member. The bottom surface extends at least partially below a substrate supported by the substrate support member. The adjustable tuning ring is positioned below the first ring. The top surface of the adjustable tuning ring defines an adjustable gap with the first ring. The actuation mechanism interfaces with the bottom surface of the adjustable tuning ring. The actuation mechanism is configured to change the adjustable gap defined between the bottom surface of the first ring and the top surface of the adjustable tuning ring.

Description

Technical Field

[0001] Embodiments described herein relate generally to a substrate processing apparatus, and more particularly to an improved process kit for a substrate processing apparatus. Background Art

[0002] As semiconductor technology node advancements reduce device geometries, substrate edge critical dimension uniformity requirements become more stringent and impact die yield. Commercial plasma reactors include multiple tunable knobs for controlling process uniformity across the substrate (e.g., such as temperature, gas flow, RF power, etc.). Typically, during the etching process, a silicon substrate is etched while being electrostatically clamped to an electrostatic chuck.

[0003] During processing, a substrate resting on a substrate support may undergo a process in which material is deposited on the substrate and portions of the material are removed from the substrate, or etched away (typically in a continuous process or alternating processes). It is generally beneficial to have uniform deposition and etching rates across the substrate surface. However, process non-uniformities often exist on the substrate surface and may be significant at the periphery or edge of the substrate. These non-uniformities at the periphery can be attributed to field termination effects and are sometimes referred to as edge effects. During deposition or etching, a process kit containing at least a deposition ring is sometimes provided to advantageously influence uniformity at the periphery or edge of the substrate.

[0004] Therefore, there is a continuing need for an improved process kit for substrate processing equipment. Summary of the Invention

[0005] Embodiments described herein generally relate to a substrate processing apparatus. In one embodiment, a process kit for a substrate processing chamber is disclosed herein. The process kit includes: a first ring; an adjustable tuning ring; and an actuation mechanism. The first ring has a top surface and a bottom surface. The bottom surface is supported by a substrate support member. The bottom surface extends at least partially below a substrate supported by the substrate support member. The adjustable tuning ring is positioned below the first ring. The adjustable tuning ring has a top surface and a bottom surface. The top surface of the adjustable tuning ring defines an adjustable gap with the first ring. The actuation mechanism interfaces with the bottom surface of the adjustable tuning ring. The actuation mechanism is configured to change the adjustable gap defined between the bottom surface of the first ring and the top surface of the adjustable tuning ring.

[0006] In another embodiment, a processing chamber is disclosed herein. The processing chamber includes a substrate support member and a process kit. The substrate support member is configured to support a substrate. The process kit is supported by the substrate support member. The process kit includes: a first ring; an adjustable tuning ring; and an actuation mechanism. The first ring has a top surface and a bottom surface. The bottom surface is supported by the substrate support member. The bottom surface extends at least partially below a substrate supported by the substrate support member. The adjustable tuning ring is positioned below the first ring. The adjustable tuning ring has a top surface and a bottom surface. The top surface of the adjustable tuning ring defines an adjustable gap with the first ring. The actuation mechanism interfaces with the bottom surface of the adjustable tuning ring. The actuation mechanism is configured to change the adjustable gap defined between the bottom surface of the first ring and the top surface of the adjustable tuning ring.

[0007] In another embodiment, a method for processing a substrate is disclosed herein. A substrate is positioned on a substrate support member disposed in a substrate processing chamber. A plasma is formed above the substrate. A spacing between the adjustable tuning ring and an edge ring is adjusted by actuating the adjustable tuning ring to change the direction of plasma ions at the edge of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Therefore, in order to understand in detail the manner in which the above-mentioned features of the present disclosure are employed, a more particular description of the present disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only typical embodiments of the present disclosure and are therefore not to be considered limiting of the scope of the present disclosure, for the disclosure may admit to other equally effective embodiments.

[0009] Figure 1 is a cross-sectional view of a processing chamber according to one embodiment.

[0010] Figure 2A According to one embodiment Figure 1 An enlarged partial cross-sectional view of a processing chamber.

[0011] Figure 2B According to one embodiment Figure 1 An enlarged partial cross-sectional view of a processing chamber.

[0012] Figure 3 According to one embodiment Figure 1 A simplified cross-sectional view of a portion of a processing chamber depicting two capacitive paths.

[0013] Figure 4 According to one embodiment Figure 1 FIG. 1 is a simplified cross-sectional view of a portion of a processing chamber illustrating another advantage of the present disclosure.

[0014] For purposes of clarity, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. Additionally, elements in one embodiment may be advantageously adapted for use in other embodiments described herein. DETAILED DESCRIPTION

[0015] Figure 1 FIG2 is a cross-sectional view of a processing chamber 100 having an adjustable tuning ring 150 according to one embodiment. As shown, the processing chamber 100 is an etch chamber suitable for etching a substrate, such as substrate 101. An example of a processing chamber that may be suitable for benefiting from the present disclosure is the ® ... Processing chamber, Processing chamber and Mesa TM Processing Chambers. It is contemplated that other processing chambers, including deposition chambers and chambers from other manufacturers, may be adapted to benefit from the present disclosure.

[0016] The processing chamber 100 can be used for various plasma processes. In one embodiment, the processing chamber 100 can be used to perform dry etching using one or more etchants. For example, the processing chamber can be used to ignite a plasma from a precursor C x F y (where x and y can be different allowed combinations), O2, NF3 or a combination of the above.

[0017] The processing chamber 100 includes a chamber body 102, a lid assembly 104, and a support assembly 106. The lid assembly 104 is positioned at an upper end of the chamber body 102. The support assembly 106 emerges within an interior volume 108 defined by the chamber body 102. The chamber body 102 includes a slit valve opening 110 formed in a sidewall thereof. The slit valve opening 110 is selectively opened and closed to allow a substrate handling robot (not shown) to enter the interior volume 108.

[0018] The chamber body 102 may further include a liner 112 that surrounds the support assembly 106. The liner 112 is removable for maintenance and cleaning. The liner 112 may be made of a metal such as aluminum, a ceramic material, or any other process-compatible material. In one or more embodiments, the liner 112 includes one or more apertures 114 and a pumping channel 116 formed therein, the pumping channel being in fluid communication with a vacuum port 118. The apertures 114 provide a flow path for gas to enter the pumping channel 116. The pumping channel 116 provides an outlet for gas within the chamber 100 to pass to the vacuum port 118.

[0019] A vacuum system 120 is coupled to the vacuum port 118. The vacuum system 120 may include a vacuum pump 122 and a throttle valve 124. The throttle valve 124 regulates the flow of gas through the chamber 100. The vacuum pump 122 is coupled to the vacuum port 118 disposed in the interior volume 108.

[0020] The lid assembly 104 includes at least two stacked components configured to form a plasma volume or cavity therebetween. In one or more embodiments, the lid assembly 104 includes a first electrode 126 ("upper electrode") vertically disposed above a second electrode 128 ("lower electrode"). The upper electrode 126 and the lower electrode 128 define a plasma cavity 130 therebetween. The first electrode 126 is coupled to a power source 132, such as an RF power source. The second electrode 128 is connected to ground, thereby forming a capacitor between the two electrodes 126, 128. The upper electrode 126 is in fluid communication with a gas inlet 134. A first end of the one or more gas inlets 134 opens into the plasma cavity 130.

[0021] The lid assembly 104 may also include an isolation ring 136 that electrically isolates the first electrode 126 from the second electrode 128. The isolation ring 136 may be made of alumina or any other insulating process compatible material.

[0022] The lid assembly may further include a gas distribution plate 138 and a barrier plate 140. The second electrode 128, the gas distribution plate 138, and the barrier plate 140 may be stacked and disposed on a lid edge 142 coupled to the chamber body 102.

[0023] In one or more embodiments, the second electrode 128 may include a plurality of gas passages 144 formed below the plasma cavity 130 to allow gas from the plasma cavity 130 to flow therethrough. The gas distribution plate 138 includes a plurality of apertures 146 configured to distribute gas flow therethrough. A blocking plate 140 may optionally be disposed between the second electrode 128 and the gas distribution plate 138. The blocking plate 140 includes a plurality of apertures 148 for providing a plurality of gas passages from the second electrode 128 to the gas distribution plate 138.

[0024] The support assembly 106 can include a support member 180. The support member 180 is configured to support the substrate 101 for processing. The support member 180 can be coupled to a lift mechanism 182 via a shaft 184 that extends through the bottom surface of the chamber body 102. The lift mechanism 182 can be flexibly sealed to the chamber body 102 by a bellows 186 that prevents vacuum leakage around the shaft 184. The lift mechanism 182 allows the support member 180 to move vertically within the chamber body 102 between a lower transfer section and a plurality of elevated process positions. Additionally, one or more lift rods 188 can be disposed through the support member 180. The one or more lift rods 188 are configured to extend through the support member 180 so that the substrate 101 can be elevated from the surface of the support member 180. The one or more lift rods 188 are movable via a lift ring 190.

[0025] Figure 2A is a partial cross-sectional view of a portion of the processing chamber 100 showing a process kit 200 disposed on a support member 180 according to one embodiment. The support member 180 includes an electrostatic chuck 202, a cooling plate (or cathode) 204, and a base 206. The cooling plate 204 is disposed on the base 206. The cooling plate 204 may include a plurality of cooling channels (not shown) to circulate a coolant therethrough. The cooling plate 204 may be engaged with the electrostatic chuck 202 by an adhesive or any suitable mechanism. One or more power supplies 208 may be coupled to the cooling plate 204. The electrostatic chuck 202 may include one or more heaters (not shown). The one or more heaters may be independently controllable. The one or more heaters enable the electrostatic chuck 202 to heat the substrate 101 to a desired temperature from the bottom surface of the substrate 101.

[0026] The process kit 200 can be supported on the support member 180. The process kit 200 includes an edge ring 210 having an annular body 230. The body 230 includes a top surface 209, a bottom surface 211, an inner edge 232, and an outer edge 234. The top surface 209 is substantially parallel to the bottom surface 211. The inner edge 232 is substantially parallel to the outer edge 234 and substantially perpendicular to the bottom surface 211. The body 230 also includes a stepped surface 236 defined therein. The stepped surface 236 is formed in the inner edge 232 such that the stepped surface 236 is substantially parallel to the bottom surface 211. The stepped surface 236 defines a recess for receiving a substrate (e.g., substrate 101). The edge ring 210 is adapted to cover the outer periphery of the support member 180 and protect the support member 180 from deposition.

[0027] The process kit 200 may also include a cover ring 212 and a quartz ring 214. The cover ring 212 includes an annular body 238 having a top surface 240, a bottom surface 242, an inner edge 244, and an outer edge 246. The top surface 240 is substantially parallel to the bottom surface 242. The inner edge 244 is substantially parallel to the outer edge 246 and substantially perpendicular to the bottom surface 242. Figure 2A In the embodiment shown in FIG, a groove 248 is formed in the bottom surface 242 of the body 238. A quartz ring 214 is positioned adjacent to the support member 180. The quartz ring 214 includes an annular body 251 having a top surface 252, a bottom surface 254, an inner edge 256, and an outer edge 258. The quartz ring 214 is configured to support the cover ring 212 in the processing chamber 100. For example, in the embodiment shown, the quartz ring 214 supports the cover ring 212 from the bottom surface 242 of the cover ring 212. In some embodiments, the quartz ring 214 may include a protruding member 263. The protruding member 263 protrudes from the top surface 252 of the quartz ring. The protruding member 263 is configured to mate with the groove 248 formed in the bottom surface 242 of the cover ring 212. The cover ring 212 is positioned along the outer periphery 216 of the edge ring 210. The edge ring 210 is configured to prevent particles from sliding underneath the edge ring 210.

[0028] The process kit 200 also includes an adjustable tuning ring 150 having a top surface 215 and a bottom surface 217. The adjustable tuning ring 150 can be formed from a conductive material such as aluminum. The adjustable tuning ring 150 is positioned below the edge ring 210, between the quartz ring 214 and the support member 180, thereby forming a gap 250. For example, in one embodiment, the adjustable tuning ring 150 extends downward along the side of the cooling plate 204 past the electrostatic chuck 202. In one embodiment, the adjustable tuning ring 150 has a height that extends all the way to the bottom of the cooling plate 204. Thus, the adjustable tuning ring 150 can couple power from the cooling plate 204 to the edge ring 210. The adjustable tuning ring 150 can encircle the cooling plate 204, thereby forming a laterally spaced gap 255. In one example, the laterally spaced gap is greater than 0 inches and less than or equal to 0.03 inches. The adjustable tuning ring 150 interfaces with the lifting pins 218. For example, the lift rods 218 can be operably coupled to the adjustable tuning ring 150. The lift rods 218 are driven by the lift mechanism 183. In some embodiments, the lift rods 218 can be driven by a lift mechanism (not shown) that is independent of the lift mechanism 183. The lift mechanism 183 allows the adjustable tuning ring 150 to move vertically within the chamber 100. In one embodiment, the adjustable tuning ring can move vertically between greater than 0 mm and less than or equal to 4 mm, for example, between 2 mm and 4 mm. Vertically moving the adjustable tuning ring 150 changes the RF power coupled to the edge ring. In one embodiment, the adjustable tuning ring 150 can include a coating 281 formed on the top surface 215 of the adjustable tuning ring 150. For example, the coating 281 can be an yttrium oxide coating or a gel-like coating. The coating 281 is used to limit chemical reactions between the plasma and the adjustable tuning ring 150, and thereby limit particle formation and ring damage. In another embodiment, one or more dielectric pads (e.g., Teflon pads) 289 are positioned between the edge ring 210 and the electrostatic chuck, on which the edge ring 210 is placed. The one or more dielectric pads 289 form a gap between the edge ring 210 and the electrostatic chuck to reduce capacitance 302, thereby minimizing power coupled from the cathode to the edge ring 210.

[0029] In another embodiment (such as Figure 2B), the adjustable tuning ring 150 can be moved manually, thereby eliminating the need for the lifting rod 218. The tuning ring 150 may include a cavity 260 and an access aperture 262 formed therein. The access aperture 262 is formed from the top of the adjustable tuning ring 150 and extends downward into the cavity 260. The access aperture 262 has a first diameter 264 that is smaller than a second diameter 265 of the cavity 260. The cavity 260 is formed below the access aperture 262. The cavity 260 is formed downward to the bottom of the tuning ring 150. The cavity 260 is configured to accommodate a screw 266. The screw 266 can be turned via a hexagonal wrench (not shown), for example, thereby extending into the cavity 260 via the access aperture 262, so that the screw 266 can raise / lower the tuning ring 150.

[0030] Figure 3 According to one embodiment Figure 1 2 is a simplified cross-sectional view of a portion of a processing chamber depicting two capacitors. Power can be coupled from the cooling plate 204 to the edge ring along two paths passing through the two capacitors 302, 304. The amount of power coupled depends on the capacitance along these two paths. Capacitor 302 is fixed. Capacitor 304 can be varied. For example, capacitor 304 can be tuned by moving the adjustable tuning ring 150 in a vertical direction below the edge ring 210, thereby modifying the gap 250 formed therebetween. Controlling the gap 250 between the adjustable tuning ring 150 and the edge ring 210 controls the capacitance therebetween. Mathematically, the capacitance can be represented as Where ε represents the dielectric constant of the material between the two electrodes (air is 1 in the case of gap 250), ε0 represents the dielectric constant of free space, area represents the area of ​​the adjustable tuning ring 150, and gap represents gap 250. As shown in the figure, as the gap decreases, The value of increases, which results in an increase in the total capacitance C. As the gap increases, that is, as the adjustable tuning sleeve moves further away from the edge ring 210, The value of decreases, which reduces the total capacitance C. Thus, controlling the gap value changes the capacitance between the edge ring 210 and the cathode 204. The change in capacitance changes the power coupled between the edge ring 210 and the cathode 204, and therefore changes the voltage applied to the edge ring 210. For example, as the gap 250 decreases, the capacitance increases, and the voltage applied to the edge ring 210 increases. Controlling the voltage applied to the edge ring 210 allows control of the plasma sheath surrounding the substrate 101 and the edge ring 210. Its effects are discussed below in conjunction with Figure 4 Discuss in more detail.

[0031] Figure 4A portion of a processing chamber 100 is shown according to one embodiment, illustrating another advantage of the present disclosure. Adjusting the vertical gap 402 between the adjustable tuning ring 150 and the edge ring 210 increases / decreases the voltage applied to the edge ring 210. The voltage can be used to control the distribution of the plasma sheath 404 at the edge 406 of the substrate 101 to compensate for critical dimension uniformity at the substrate edge 406. The plasma sheath 404 is a thin region of strong electric field formed by space charge, which binds the plasma body to its material boundaries. Mathematically, the sheath thickness d is expressed by the Child-Langmuir equation:

[0032]

[0033] where i is the ionic current density, ε is the dielectric constant of vacuum, e is the elementary charge, and V p is the plasma potential, and V DC is a DC voltage.

[0034] In the case of an etch reactor, a plasma sheath 404 is formed between the plasma and the substrate 101 being etched, the chamber body 102, and other parts of the processing chamber 100 that are in contact with the plasma. Ions generated in the plasma are accelerated in the plasma sheath and move perpendicular to the plasma sheath. Control V DC (ie, controlling the voltage applied to the edge ring 210) affects the thickness d of the shell 404. For example, as the voltage increases due to a decrease in capacitance, the thickness of the shell 404 decreases because V p -V DC Thus, moving the adjustable tuning ring 150 affects the shape of the shell 404, which in turn controls the direction of the plasma ions.

[0035] Return Reference Figure 1 Control of the adjustable tuning ring may be controlled by a controller 191. The controller 191 includes a programmable central processing unit (CPU) 192 that operates in conjunction with a memory 194 and mass storage devices, an input control unit, and a display unit (not shown) coupled to various components of the processing system, such as power supplies, clocks, caches, input / output (I / O) circuits, and liners, to facilitate control of substrate processing.

[0036] To facilitate control of the chamber 100 described above, the CPU 192 can be any form of general-purpose computer processor that can be used in an industrial environment, such as a programmable logic controller (PLC), for controlling the various chambers and sub-processors. Memory 194 is coupled to the CPU 192 and is non-transitory and can be one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), a floppy disk drive, a hard disk, or any other form of digital storage device (whether local or remote). Support circuits 196 are coupled to the CPU 192 to support the processor in a conventional manner. Charged species generation, heating, and other processes are generally stored in the memory 194, typically as software routines. The software routines can also be stored and / or executed by a second CPU (not shown) remote from the processing chamber 100 controlled by the CPU 192.

[0037] The memory 194 is in the form of a computer-readable storage medium containing instructions that, when executed by the CPU 192, facilitate the operation of the chamber 100. The instructions in the memory 194 are in the form of a program product, such as a program that implements the methods of the present disclosure. The program code may conform to any of a number of different programming languages. In one example, the present disclosure may be implemented as a program product stored on a computer-readable storage medium for use with a computer system. The program of the program product defines the functionality of the embodiments (including the methods described herein). Illustrative computer-readable storage media include, but are not limited to: (i) a non-writable storage medium on which information is permanently stored (e.g., a read-only memory device within a computer, such as a CD-ROM disk, flash memory, ROM chip, or any type of solid-state non-volatile semiconductor memory that can be read by a CD-ROM drive); and (ii) a writable storage medium on which information that can be modified is stored (e.g., a floppy disk within a disk drive or hard drive, or any type of solid-state random access semiconductor memory). When executing computer-readable instructions that indicate the functionality of the methods described herein, such computer-readable storage media are embodiments of the present disclosure.

[0038] While the foregoing is directed to particular embodiments, other and further embodiments may be devised without departing from the basic scope of the invention, and the scope of the invention is determined by the appended claims.

[0039] Component Symbol List

[0040] 100 Chambers (5)

[0041] 101 base plate(9)

[0042] 102 Chamber body (10)

[0043] 104 Cover assembly (5)

[0044] 106 Support Components (4)

[0045] 108 Internal Volume (3)

[0046] 110 Slit valve opening (2)

[0047] 112 Lining (4)

[0048] 114 pores (2)

[0049] 116 Pumping channels (3)

[0050] 118 Vacuum ports (4)

[0051] 120 Vacuum System (2)

[0052] 122 Vacuum Pumps (2)

[0053] 124 Throttle valve (2)

[0054] 126 first electrode (3)

[0055] 128 lower electrode

[0056] 130 Plasma Cavity (4)

[0057] 132 Power Supply

[0058] 134 Gas Inlet

[0059] 134 Gas Inlet

[0060] 136 Isolation Ring (2)

[0061] 138 Gas distribution plate (5)

[0062] 140 Blocking Plates (4)

[0063] 142 Cover edge

[0064] 144 Gas Path

[0065] 146 pores

[0066] 148 pores

[0067] 150 Adjustable Tuning Rings (21)

[0068] 150 Tuning Rings (4)

[0069] 180 Support members (14)

[0070] 182 Lifting Mechanism (3)

[0071] 183 Lifting Mechanism (3)

[0072] 184 Shafts (2)

[0073] 186 bellows

[0074] 188 Lifting Rods (3)

[0075] 190 lifting ring

[0076] 191 Controllers(2)

[0077] 192 CPU(5)

[0078] 194 Memory (6)

[0079] 196 Support Circuits

[0080] 200 Craft Kits (5)

[0081] 202 Electrostatic chuck (5)

[0082] 204 cathode (3)

[0083] 206 base (2)

[0084] 208 Power Supply

[0085] 209 top surface (2)

[0086] 210 Edge Ring (22)

[0087] 210 rings

[0088] 211 bottom surface (4)

[0089] 212 Cover Ring (7)

[0090] 214 Quartz Rings (7)

[0091] 215 top surface (2)

[0092] 216 outer perimeter

[0093] 217 bottom surface

[0094] 218 Lifting Rods (5)

[0095] 230 Ring body

[0096] 230 Main body (2)

[0097] 232 inner edge (3)

[0098] 234 outer edge (2)

[0099] 236 Stepped Surface (4)

[0100] 238 Ring body

[0101] 238 Subject

[0102] 240 Top Surface (2)

[0103] 242 bottom surface (6)

[0104] 244 inner edge (2)

[0105] 246 outer edge (2)

[0106] 248 grooves (2)

[0107] 250 Gap (6)

[0108] 251 Ring body

[0109] 252 top surface (2)

[0110] 254 bottom surface

[0111] 255 Lateral spacing gap

[0112] 256 Inner Edge

[0113] 258 outer edge

[0114] 260 Cavity (7)

[0115] 262 Inlet and outlet openings (4)

[0116] 263 protruding components (3)

[0117] 264 First Diameter

[0118] 265 Second diameter

[0119] 266 screws (3)

[0120] 281 Coating (3)

[0121] 289 Dielectric Pad

[0122] 302 Capacitors (2)

[0123] 304 Capacitors (2)

[0124] 402 Vertical Clearance

[0125] 404 Plasma Sheath

[0126] 406 Edge

Claims

1. A process kit for a substrate processing chamber, comprising: an edge ring having a top surface and a bottom surface, the bottom surface being supported by a substrate support member, the bottom surface extending at least partially below a substrate supported by the substrate support member; an adjustable tuning ring positioned below the edge ring, the adjustable tuning ring having a top surface and a bottom surface, the top surface of the adjustable tuning ring defining an adjustable gap with the edge ring, the adjustable tuning ring comprising: annular body; a cavity formed in the annular body, the cavity being formed in the bottom surface of the annular body; and an access aperture formed in the annular body, the access aperture extending from the top surface of the adjustable tuning ring into the cavity and having a first diameter that is smaller than a second diameter of the cavity; and An actuation mechanism is received in the cavity, the actuation mechanism configured to modify the adjustable gap defined between the bottom surface of the edge ring and the top surface of the adjustable tuning ring.

2. The process kit of claim 1, wherein the adjustable tuning ring is formed of a conductive material.

3. The process kit of claim 1, wherein the adjustable gap is adjustable between 0 mm and 4 mm.

4. The process kit of claim 1 , wherein the actuation mechanism is a screw at least partially disposed in a cavity, the screw being configured to be rotated through the access aperture to actuate the adjustable tuning ring. 5 . The process kit of claim 1 , wherein the actuation mechanism is configured to control a thickness of a plasma sheath formed between plasma and the edge ring.

6. A processing chamber comprising: a substrate support member configured to support a substrate; as well as A process kit, the process kit being supported by the substrate support member, the process kit comprising: an edge ring having a top surface and a bottom surface, the bottom surface being supported by the substrate support member, the bottom surface extending at least partially below the substrate supported by the substrate support member; an adjustable tuning ring positioned below the edge ring, the adjustable tuning ring having a top surface and a bottom surface, the top surface of the adjustable tuning ring defining an adjustable gap with the edge ring, wherein the adjustable tuning ring comprises: annular body; a cavity formed in the annular body, the cavity being formed in the bottom surface of the annular body; and an access aperture formed in the annular body, the access aperture extending from the top surface of the adjustable tuning ring into the cavity and having a first diameter that is smaller than a second diameter of the cavity; and An actuation mechanism is received in the cavity, the actuation mechanism configured to modify the adjustable gap defined between the bottom surface of the edge ring and the top surface of the adjustable tuning ring.

7. The processing chamber of claim 6, wherein the adjustable tuning ring is formed of a conductive material.

8. The processing chamber of claim 6, wherein the adjustable gap is adjustable between 0 mm and 4 mm.

9. The processing chamber of claim 6, wherein the actuation mechanism is a screw at least partially disposed in the cavity, the screw being configured to be rotated through the access aperture to actuate the adjustable tuning ring.

10. The processing chamber of claim 6, wherein the actuation mechanism is configured to control a thickness of a plasma sheath formed between plasma and the edge ring.

11. The processing chamber of claim 6, wherein the substrate support member comprises: base; a cooling plate supported by the base; as well as An electrostatic chuck is positioned on the top surface of the cooling plate.

12. The processing chamber of claim 11, wherein the adjustable tuning ring is spaced apart from the cooling plate by between 0 mm and 2 mm.

13. A method of processing a substrate using the process kit of any one of claims 1 to 5 or in the processing chamber of any one of claims 6 to 12, comprising: positioning the substrate on a substrate support member disposed in a substrate processing chamber; forming a plasma above the substrate; as well as The spacing between the adjustable tuning ring and the edge ring is adjusted by actuating the adjustable tuning ring to change the ion direction at the edge of the substrate, wherein actuating the adjustable tuning ring includes rotating a screw at least partially disposed in a cavity within the adjustable tuning ring.

14. The method of claim 13, wherein actuating the adjustable tuning ring comprises: A thickness of a plasma sheath formed between the plasma and the edge ring is modified.

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