WO2025217009A1

WO2025217009A1 - Edge ring compensation monitoring and adjustment during plasma processing

Info

Publication number: WO2025217009A1
Application number: PCT/US2025/023370
Authority: WO
Inventors: Anthony Michael OLIVETI; Gabriel Anthony CALEBOTTA; John Holland; Tigran POGHOSYAN
Original assignee: Lam Research Corp
Current assignee: Lam Research Corp
Priority date: 2024-04-09
Filing date: 2025-04-07
Publication date: 2025-10-16
Anticipated expiration: 2026-10-09
Also published as: TW202603834A

Abstract

A system includes a substrate support with an electrostatic chuck and an edge ring, an edge ring RF power source configured to provide an RF voltage to the edge ring based on a tuning edge sheath compensation during processing of a substrate, a measurement power source configured to provide an RF voltage to the electrostatic chuck and the edge ring, and a controller configured to determine an impedance associated with the electrostatic chuck and an impedance associated with the edge ring based on the RF voltage provided to the electrostatic chuck and the edge ring from the measurement power source, adjust the tuning edge sheath compensation based on the impedance associated with the electrostatic chuck and the impedance associated with the edge ring, and control the edge ring RF power source to adjust the RF voltage based on the adjusted tuning edge sheath compensation.

Description

EDGE RING COMPENSATION MONITORING AND ADJUSTMENT DURING PLASMA PROCESSING

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/631 ,831 , filed on April 9, 2024. The entire disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure relates to substrate processing, and more particularly to monitoring and adjusting tuning edge sheath compensations for edge rings within substrate processing chambers.

BACKGROUND

[0003] The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0004] A substrate processing system may be used to treat substrates such as semiconductor wafers in a processing chamber. Example processes that may be performed on a substrate include chemical vapor deposition (CVD), atomic layer deposition (ALD), conductor etch, and/or other etch, deposition, or cleaning processes. In the processing chamber, a substrate may be arranged on a substrate support having an electrostatic chuck (ESC) and an edge ring surrounding the ESC. During etching, gas mixtures may be introduced into the processing chamber and plasma may be used to initiate chemical reactions.

[0005] During processing of a substrate using plasma, a plasma boundary layer (referred to as a plasma sheath) is formed above a surface of the substrate. Plasma sheath thickness depends on various factors, including applied voltages. For example, a voltage may be applied to the edge ring that is larger than a voltage applied to the ESC. SUMMARY

[0006] A system includes a substrate support positioned within a substrate processing chamber. The substrate support includes an electrostatic chuck and an edge ring positioned about the electrostatic chuck. The system further includes an edge ring RF power source configured to provide an RF voltage to the edge ring based on a tuning edge sheath compensation during processing of a substrate in the substrate processing chamber, a measurement power source configured to provide an RF voltage to the electrostatic chuck and the edge ring, and a controller in communication with at least the edge ring RF power source and the measurement power source. The controller is configured to determine an impedance associated with the electrostatic chuck and an impedance associated with the edge ring based on the RF voltage provided to the electrostatic chuck and the edge ring from the measurement power source, adjust the tuning edge sheath compensation based on the impedance associated with the electrostatic chuck and the impedance associated with the edge ring, and control the edge ring RF power source to adjust the RF voltage based on the adjusted tuning edge sheath compensation.

[0007] In other features, the system further includes one or more sensors configured to detect a voltage and a current at the edge ring. The controller is configured to receive the voltage and the current, and determine the impedance associated with the edge ring based on the voltage and the current.

[0008] In other features, the system further includes an isolation network coupled between the measurement power source and the edge ring.

[0009] In other features, the system further includes a power amplifier coupled between the isolation network and the measurement power source.

[0010] In other features, the one or more sensors are configured to detect a voltage and a current at the electrostatic chuck, and the controller is configured to receive the voltage and the current at the electrostatic chuck, and determine the impedance associated with the electrostatic chuck based on the voltage and the current at the electrostatic chuck.

[0011] In other features, the system further includes an isolation network coupled between the measurement power source and electrostatic chuck. [0012] In other features, the system further includes a power amplifier coupled between the isolation network and the measurement power source.

[0013] In other features, the system further includes an RF power source configured to provide an RF voltage to the electrostatic chuck. The one or more sensors are configured to operate at a frequency based on the RF voltage provided to the electrostatic chuck.

[0014] In other features, the RF power source is configured to provide a sinusoidal RF voltage to the electrostatic chuck at one or more frequencies, and the one or more sensors are configured to operate at a frequency band less than or greater than the one or more frequencies of the sinusoidal RF voltage.

[0015] In other features, the RF power source is configured to provide a non- sinusoidal RF voltage to the electrostatic chuck, and the one or more sensors are configured to operate at a frequency band greater than a highest frequency of the non- sinusoidal RF voltage.

[0016] In other features, the one or more sensors include a capacitive divider network to detect the voltage.

[0017] In other features, the one or more sensors include a current transformer to detect the current.

[0018] In other features, the controller is configured to determine the impedance associated with the electrostatic chuck and the impedance associated with the edge ring when a plasma sheath formed within the substrate processing chamber is at or near a maximum thickness.

[0019] In other features, the impedance associated with the edge ring includes an impedance associated with plasma within the substrate processing chamber capacitive coupled through a plasma sheath at the edge ring and an impedance associated with a capacitive coupling to the electrostatic chuck.

[0020] In other features, the impedance associated with the electrostatic chuck includes an impedance associated with the plasma within the substrate processing chamber capacitive coupled through the plasma sheath at the electrostatic chuck and an impedance associated with a capacitive coupling to the edge ring. [0021] In other features, the controller is configured to compare the impedance associated with the electrostatic chuck and the impedance associated with the edge ring, and adjust the tuning edge sheath compensation based on the comparison.

[0022] In other features, the controller is configured to vary the tuning edge sheath compensation, and determine the impedance associated with the electrostatic chuck and the impedance associated with the edge ring while the tuning edge sheath compensation is varied.

[0023] In other features, the RF voltage provided to the electrostatic chuck and the edge ring from the measurement power source is five volts or less.

[0024] In other features, the measurement power source is configured to provide the RF voltage to the electrostatic chuck and the edge ring at a fixed frequency or a variable frequency.

[0025] In other features, the system further includes an RF power source configured to provide an RF voltage to the electrostatic chuck.

[0026] A method includes providing, with an edge ring RF power source, an RF voltage to an edge ring positioned about an electrostatic chuck in a substrate processing chamber based on a tuning edge sheath compensation, providing, with a measurement power source, an RF voltage to the electrostatic chuck and the edge ring, determining an impedance associated with the electrostatic chuck and an impedance associated with the edge ring based on the RF voltage provided to the electrostatic chuck and the edge ring from the measurement power source, adjusting the tuning edge sheath compensation based on the impedance associated with the electrostatic chuck and the impedance associated with the edge ring, and controlling the edge ring RF power source to adjust the RF voltage based on the adjusted tuning edge sheath compensation.

[0027] In other features, the method further includes detecting, with one or more sensors, a voltage and a current at the edge ring and a voltage and a current at the electrostatic chuck.

[0028] In other features, determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring includes determining the impedance associated with the electrostatic chuck based on the voltage and the current at the electrostatic chuck, and the impedance associated with the edge ring based on the voltage and the current at the edge ring.

[0029] In other features, the method further includes providing, with an RF power source, an RF voltage to the electrostatic chuck.

[0030] In other features, detecting, with one or more sensors, the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck includes detecting the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck at a frequency based on the RF voltage provided to the electrostatic chuck.

[0031] In other features, providing the RF voltage to the electrostatic chuck includes providing a sinusoidal RF voltage to the electrostatic chuck at one or more frequencies, and detecting, with one or more sensors, the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck includes detecting the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck at a frequency band less than or greater than the one or more frequencies of the sinusoidal RF voltage.

[0032] In other features, providing the RF voltage to the electrostatic chuck includes providing a non-sinusoidal RF voltage to the electrostatic chuck, and detecting, with one or more sensors, the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck includes detecting the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck at a frequency band greater than a highest frequency of the non-sinusoidal RF voltage.

[0033] In other features, determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring includes determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring when a plasma sheath formed within the substrate processing chamber is at or near a maximum thickness.

[0034] In other features, the impedance associated with the edge ring includes an impedance associated with plasma within the substrate processing chamber capacitive coupled through a plasma sheath at the edge ring and an impedance associated with a capacitive coupling to the electrostatic chuck. [0035] In other features, the impedance associated with the electrostatic chuck includes an impedance associated with the plasma within the substrate processing chamber capacitive coupled through the plasma sheath at the electrostatic chuck and an impedance associated with a capacitive coupling to the edge ring.

[0036] In other features, the method further includes comparing the impedance associated with the electrostatic chuck and the impedance associated with the edge ring.

[0037] In other features, adjusting the tuning edge sheath compensation includes adjusting the tuning edge sheath compensation based on the comparison.

[0038] In other features, the method further includes varying the tuning edge sheath compensation.

[0039] In other features, determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring includes determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring while the tuning edge sheath compensation is varied.

[0040] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0042] FIG. 1 is a block diagram of an example substrate processing system, according to the present disclosure;

[0043] FIG. 2 is a block diagram of another example substrate processing system, according to the present disclosure;

[0044] FIG. 3 is a block diagram illustrating different plasma sheath profiles based on different tuning edge sheath compensations, according to the present disclosure;

[0045] FIG. 4 is a block diagram illustrating reactive loads detected by a measurement system when a measurement power source is coupled to an edge ring, according to the present disclosure; [0046] FIG. 5 is a block diagram illustrating reactive loads detected by a measurement system when a measurement power source is coupled to an ESC, according to the present disclosure;

[0047] FIG. 6 is a block diagram illustrating reactive loads detected by a measurement system when a tuning edge sheath factor is varied and a measurement power source is coupled to an edge ring, according to the present disclosure;

[0048] FIG. 7 is a block diagram illustrating reactive loads detected by a measurement system when a tuning edge sheath factor is varied and a measurement power source is coupled to an ESC, according to the present disclosure;

[0049] FIG. 8 is a graph showing sensor frequency bands for a sinusoidal RF bias voltage signal provided at a frequency, according to the present disclosure;

[0050] FIG. 9 is a graph showing sensor frequency bands for a sinusoidal RF bias voltage signal provided at multiple frequencies, according to the present disclosure;

[0051] FIG. 10 is a graph showing a sensor frequency band for a non-sinusoidal RF bias voltage signal, according to the present disclosure;

[0052] FIG. 11 is a diagram of an example capacitive divider network, according to the present disclosure;

[0053] FIG. 12 is a diagram of an example current transformer, according to the present disclosure; and

[0054] FIG. 13 is a flow chart of an example method for monitoring and adjusting a tuning edge sheath compensation in a substrate processing system, according to the present disclosure;

[0055] In the drawings, reference numbers may be reused to identify similar and/or identical elements.

DETAILED DESCRIPTION

[0056] In a processing chamber of a substrate processing system, a substrate may be arranged on a substrate support having an ESC and an edge ring surrounding the ESC. During processing of the substrate (e.g., a semiconductor wafer, etc.) using plasma, a plasma sheath is formed above a surface of the substrate. The thickness of the plasma sheath may be adjusted in various manners. For example, different voltages may be applied to the edge ring and the ESC to modulate the plasma sheath thickness near an edge of the substrate. This ratio of the applied voltages to the edge ring and the ESC is often referred to as a tuning edge sheath (TES) factor. To obtain an optimal TES factor, characterization of the processing chamber across different process conditions may be necessary. However, over time the edge ring erodes. This change in geometry of the edge ring results in a change in the optimal TES factor. Therefore, it may be necessary to characterize the erosion profile of the edge ring and resulting effect on the optimal TES factor. Compensation to the TES factor, however, is applied in an open-loop system, such that real time monitoring does not occur. As such, while adjustments to the TES factor may occur, the adjustments are made over extended periods of time as the edge ring erodes. Such adjustments are not tailored to an individual processing chamber and do not consider the actual edge ring erosion profile for an individual edge ring. As such, any variance of such factors from one processing chamber to another processing chamber and/or from one edge ring to another edge ring cannot be accounted for in an open-loop system.

[0057] The TES compensation systems and methods according to the present disclosure enable the monitoring and adjustment of a TES compensation over the course of erosion of an edge ring in a substrate processing chamber. For example, a low RF voltage is applied to both an ESC and the edge ring, in addition to RF voltages applied to the edge ring and the ESC from an edge ring power source and an ESC power source for modulating a plasma sheath thickness. This low RF voltage is provided to determine effective reactive loads on the ESC and the edge ring by the plasma and resulting plasma sheath based on sensed feedback in a closed-loop system. Then, TES compensation adjustments may be made based on the determined effective reactive loads on the ESC and the edge ring. Therefore, with this closed-loop, feedback system, if determined reactive loads diverge over time from initial settings corresponding to a TES factor, the TES compensation systems and methods herein can modulate the TES factor to maintain optimal operation. Additionally, as the impact of edge ring erosion in the processing chamber is monitored in real time, an optimal TES factor may be learned over the course of normal operation. As such, through the real-time monitoring, information may be unlocked to enable TES factor adjustment and optimalization, thereby allowing preventative maintenance to be performed to extend plasma membrane (PM) cycles and/or executing PM cycles when performance is likely to be degraded. [0058] For example, a controller may be employed to determine an impedance associated with the ESC and an impedance associated with the edge ring based on the applied low RF voltage. Then, the controller may adjust the TES compensation based on the determined impedances associated with the ESC and the edge ring. Once the adjustment of the TES compensation is determined, the controller may control the edge ring power source to adjust the RF voltage applied to the edge ring based on the adjusted TES compensation.

[0059] Referring now to FIG. 1 , an example substrate processing system 100 is shown. For example only, the substrate processing system 100 may be used for performing etching using RF plasma and/or other suitable substrate processing. The substrate processing system 100 includes a processing chamber 102 that encloses other components of the substrate processing system 100 and contains the RF plasma. The processing chamber 102 includes an upper electrode 104, and a substrate support 106 having an ESC 108 and an edge ring 110 positioned about the ESC 108. During operation, a substrate 112 is arranged on the substrate support 106. While a specific substrate processing system 100 and processing chamber 102 are shown as an example, the principles of the present disclosure may be applied to other types of substrate processing systems and chambers, such as a substrate processing system that generates plasma in-situ, that implements remote plasma generation and delivery (e.g., using a plasma tube, a microwave tube), etc.

[0060] In some embodiments, the upper electrode 104 may include a gas distribution device such as a showerhead 114 that introduces and distributes process gases. The showerhead 114 may include a stem portion having one end connected to a top surface of the processing chamber 102. In such examples, a base portion may be generally cylindrical and extend radially outwardly from an opposite end of the stem portion at a location that is spaced from the top surface of the processing chamber 102. A substrate-facing surface or faceplate of the base portion of the showerhead may include multiple holes through which process gas or purge gas flows. Alternately, the upper electrode 104 may include a conducting plate and the process gases may be introduced in another manner.

[0061] The ESC 108 of the substrate support 106 includes a conductive baseplate 116 that acts as a lower electrode. In such examples, the baseplate 116 may support a ceramic layer (not shown). In some examples, the ceramic layer may include a heating layer, such as a ceramic multi-zone heating plate. A thermal resistance layer (e.g., a bond layer) may be arranged between the ceramic layer and the baseplate 116. The baseplate 116 may include one or more coolant channels for flowing coolant through the baseplate 116.

[0062] As shown in FIG. 1 , the substrate processing system 100 includes RF generating systems 118, 120 that generate and output RF voltages to the upper electrode 104 and the lower electrode (e.g., the baseplate 116 of the ESC 108), respectively. In the example of FIG. 1 , the RF generating system 118 includes an RF power source 122 that is controlled to generate an RF voltage that is fed by a matching and distribution network 124 to the upper electrode 104. Similarly, the RF generating system 120 includes an RF power source 126 that is controlled to generate an RF voltage that is fed by a matching and distribution network 128 to the baseplate 116. In such examples, the RF generating system 120 may be a main RF generating system and the RF generating system 120 may be a bias RF generating system. In other examples, one of the upper electrode 104 and the baseplate 116 may be DC grounded, AC grounded or floating. In other examples, the plasma may be generated inductively or remotely. Although, as shown for example purposes, the RF generating systems 118, 120 correspond to a capacitively coupled plasma (CCP) system, the principles of the present disclosure may also be implemented in other suitable systems, such as, for example only transformer coupled plasma (TCP) systems, CCP cathode systems, remote microwave plasma generation and delivery systems, etc.

[0063] The substrate processing system 100 further includes a TES bias system 138 that generates and outputs an RF voltage to the edge ring 110 based on a TES compensation during processing of the substrate 112 in the processing chamber 102. For example, the TES bias system 138 may include an edge ring RF power source that is controlled to provide the RF voltage to an electrode in the edge ring 110. In such examples, the edge ring RF power source (or more broadly the TES bias system 138) itself may generate the RF voltage for the edge ring 110 or the edge ring RF power source may convert an RF voltage received from the RF generating system 120. In either case, the RF voltage from the edge ring RF power source may be different (e.g., larger) than the RF voltage applied to the ESC 108 (from the RF power source 126), but at the same frequency and phase. The applied bias voltage to the edge ring 110 modulates a plasma sheath thickness near an edge of the substrate 112 (e.g., near the edge ring 110). The ratio of the applied voltages (e.g., a TES factor) to the ESC 108 and the edge ring 110 is a controllable parameter that can be adjusted according to the TES compensation, as further explained below, to obtain an optimal TES factor for creating a desired plasma sheath profile.

[0064] The substrate processing system 100 further includes a gas delivery system 130 and an exhaust system 132. In such examples, the gas delivery system 130 may include one or more gas sources, valves, and mass flow controllers. In various embodiments, the gas sources supply one or more etch gases, carrier gases, inert gases, etc., and mixtures thereof. The gas sources may also supply purge gas. The gas sources may be connected by the valves and the mass flow controllers to a manifold, the output of which is fed to the processing chamber 102. For example only, the output of the manifold may be fed to the showerhead 114 in the processing chamber 102. In the example of FIG. 1 , the exhaust system 132 includes a valve 134 and a pump 136 to control pressure in the processing chamber 102 and/or to remove reactants from the processing chamber 102 by purging or evacuation.

[0065] A controller 140 controls various aspects of the substrate processing system 100, such as the etching process and the components of the substrate processing system 100 described above. For example, the controller 140 monitors system parameters and controls delivery of the gas mixture from the gas delivery system 130 and removal of reactants from the processing chamber 102. Additionally, the controller 140 controls striking, maintaining, and extinguishing the plasma. Further, the controller 140 controls various aspects of the systems 118, 120, 138, such as the RF voltage sources and the matching and distribution networks in the systems 118, 120, 138.

[0066] As shown, the substrate processing system 100 further includes a measurement system 150 and a measurement power source 152. In the example of FIG. 1 , the measurement power source 152 may be a broadband voltage source that provides an RF voltage to the ESC 108 and the edge ring 110. The RF voltage provided to the ESC 108 and the edge ring 110 may be, for example, a low, constant voltage (e.g., 5 V or less) signal. In some embodiments, the measurement power source 152 may provide the RF voltage via the measurement system 150 as shown in FIG. 1.

[0067] In various embodiments, the low voltage signal from the measurement power source 152 may have a fixed or variable frequency. For example, the measurement power source 152 may operate at a fixed frequency that is known to have adequate sensitivity to changes in reactance caused by erosion in the edge ring 110 and changes in TES compensation. This may be advantageous as it permits simple circuit implementation and controller calculations. In other examples, the measurement power source 152 may delivery a swept frequency signal (e.g., a variable frequency in the range of 30 MHz to 120 MHz) where multiple points across the frequency span can be sampled to obtain a more accurate model of the change in reactance caused by erosion in the edge ring 110 and changes in TES compensation.

[0068] In the example of FIG. 1 , the measurement system 150 includes one or more sensors for determining effective reactive loads on the ESC 108 and the edge ring 110 by the plasma and resulting plasma sheath formed above the substrate 112. For example, the measurement system 150 may include one or more voltage sensors and current sensors to detect voltages and currents at the ESC 108 and the edge ring 110 based on the RF voltage applied to the ESC 108 and the edge ring 110 from the measurement power source 152. In such examples, the detected voltages and currents are fed back to the controller 140, where the controller 140 can determine an impedance associated with the ESC 108 and an impedance associated with the edge ring 110 based on the detected voltages and currents. Then, the controller 140 can adjust the TES compensation based on the impedances associated with the ESC 108 and the edge ring 110, and control the edge ring RF power source in the TES bias system 138 to adjust the RF voltage based on the adjusted tuning edge sheath compensation. In doing so, the TES factor may be altered to create a desired plasma sheath profile during processing of the substrate 112 in the processing chamber 102 even if the edge ring 110 has eroded over time.

[0069] For example, as the edge ring 110 erodes, the TES factor becomes suboptimal and the profile of the plasma sheath shifts. If the erosion causes the TES compensation to be too little, the plasma sheath may shrink in the vicinity of the edge ring 110, as further explained below. In such cases, the load placed on the edge ring 110 will therefore be modulated. By measuring the effective loads of the ESC 108 and of the edge ring 110, and comparing them for a given process condition (e.g., a gas composition, a chamber process, individual gas flow rates, RF power applied by the RF generating system 120, etc.), a determination about the effect of edge ring 110 erosion may be made (e.g., continuously, periodically, randomly, etc.) and TES compensation correction or preventative maintenance may be performed. This may, in some embodiments, take the form of learned TES compensation factors for given measurements of the reactive loads on the ESC 108 and the edge ring 110. In addition, it may also take the form of a startup procedure where the measurements are taken upon installation of a new edge ring to ensure correct TES compensation factor in order to reduce the impact of edge ring installation variation. In such examples, the edge ring characteristics vary due to, for example, machining tolerances, installation, gel characteristics and compression.

[0070] In some examples, the measurement system 150 may include various components in addition to the sensors for determining effective reactive loads on the ESC 108 and the edge ring 110. For example, FIG. 2 depicts a substrate processing system 200 including one example implementation of the measurement system 150 of FIG. 1. As shown, the substrate processing system 200 generally includes the substrate support 106, the measurement system 150, the measurement power source 152, and the controller 140 of FIG. 1. In such examples, the substrate support 106 includes the ESC 108 and the edge ring 110 for supporting the substrate 112 during processing of the substrate 112.

[0071] In the example of FIG. 2, the substrate processing system 200 further includes RF power sources 220, 238 for generating and providing RF voltages to the ESC 108 and the edge ring 110. For example, the RF power source 220 may be controlled by the controller 140 to generate and provide an RF voltage to an electrode 216 in the ESC 108, and the RF power source (e.g., an edge ring RF power source) 238 may be controlled by the controller 140 to generate and provide an RF voltage to an electrode 218 in the edge ring 110. In various embodiments, the RF power source 238 itself may generate the RF voltage for the edge ring 110 or convert an RF voltage received from the RF power source 220. In such examples, the RF power sources 220, 238 may provide differing RF voltages to the ESC 108 and the edge ring 110 to adjust a plasma sheath profile, as explained herein.

[0072] For example, the RF power source 238 may apply a voltage to the edge ring 110 some proportion higher than the RF voltage applied by the RF power source 220 to the ESC 108 to provide a TES compensation to the edge ring 110. This additional voltage to the edge ring 110 serves to flatten the plasma sheath towards the edge of the substrate 112. Without this TES compensation or too low TES compensation (e.g., the voltage applied to the edge ring 110 is too low), the plasma sheath may bow towards the substrate 112, causing the trajectory of ions to follow an angle less than 90 degrees counterclockwise from the center of the substrate 112. As a result, etched features in the substrate 112 become elongated (e.g., commonly referred to as tilt). Additionally, in some scenarios, the total ion flux causes a shift in etch rate uniformity as the proportion of ions flowing into the edge of the substrate 112 is increased. Conversely, with too much TES compensation (e.g., the voltage applied to the edge ring 110 is too high), the plasma sheath may bow away from the substrate 112, causing the trajectory of the ions to follow an angle greater than 90 degrees counterclockwise from the center of the substrate 112. This results in the opposite effect of the noncompensated or under-compensated case.

[0073] For example, FIG. 3 depicts one example of different plasma sheath profiles according to different TES compensations. In FIG. 3, the RF power sources 220, 238 apply voltages to the ESC 108 and the edge ring 110 as explained herein. As shown, when the TES compensation is too low or nonexistent, the plasma sheath bows towards the substrate 112 near the edge ring 110, as shown by line 370 having a dashdot-dot-dash configuration. This results in the trajectory of ions being at an angle less than 90 degrees counterclockwise from the center of the substrate 112, as shown by arrow 372. When the TES compensation is too high, the plasma sheath bows away the substrate 112 near the edge ring 110, as shown by line 350 having a dash-dot-dash configuration. This results in the trajectory of ions being at an angle greater than 90 degrees counterclockwise from the center of the substrate 112, as shown by arrow 352. If, however, the TES compensation is such to obtain an optimal TES factor, the plasma sheath extends across the ESC 108 and the edge ring 110, as shown by line 360 having a dash-dash-dash configuration. With this TES compensation, the trajectory of ions striking the substrate 112 is perpendicular to the substrate 112 as shown by arrow 362, thereby providing desirable etched features in the substrate 112.

[0074] With continued reference to FIG. 2, the measurement system 150 includes various components for applying an additional voltage to the ESC 108 and the edge ring 110 and determining effective reactive loads on the ESC 108 and the edge ring 110. In the example of FIG. 2, the measurement system 150 includes two measuring branches 150A, 150B having multiple sensors, isolation networks, and power amplifiers. Specifically, the measuring branch 150A of the measurement system 150 includes sensors 240, an isolation network 242 a power amplifier 244, and the measuring branch 150B of the measurement system 150 includes sensors 246, an isolation network 248 a power amplifier 250. [0075] As shown, the isolation networks 242, 248 are coupled to provide electrical isolation between the measurement power source 152 and the receiving component. Specifically, the isolation network 242 is coupled between the measurement power source 152 and the edge ring 110, and the isolation network 248 is coupled between the measurement power source 152 and the ESC 108. In such examples, the isolation networks 242, 248 may provide a high impedance to the fundamental frequency and relevant harmonics of the RF power sources 220, 238 as to not influence normal operation of processing of the substrate 112 and to protect the measurement power source 152.

[0076] In various embodiments, the isolation networks 242, 248 may include passive and/or active components. For example, one or both isolation networks 242, 248 may be passive and include only resistors, inductors, and/or capacitors to provide high isolating impedance between the main frequency source(s) (e.g., the RF power sources 220, 238) driving the ESC 108 and the edge ring 110, and the measurement system 150. This may be advantageous when the main frequency and the measurement frequency are far apart. In other examples, one or both isolation networks 242, 248 may include a set of switching devices (e.g., solid-state switches, vacuum relays, etc.) to provide broadband isolation between the main frequency source(s) driving the ESC 108 and the edge ring 110, and the measurement system 150. This configuration may be advantageous when the main source(s) 220, 238 and the measurement power source 152 are broadband and passive isolation is difficult or impractical. In still other embodiments, one or both isolation networks 242, 248 may include a combination of resistors, inductors, capacitors, and/or switching devices if desired.

[0077] As shown in FIG. 2, the power amplifiers 244, 250 are coupled between the isolation networks 242, 248 and the measurement power source 152. In such examples, the power amplifiers 244, 250 may function as matching and distribution networks for feeding a low, constant voltage signal from the measurement power source 152 to the edge ring 110 and the ESC 108, respectively.

[0078] In the example of FIG. 2, the sensors 240, 246 detect electrical characteristics on the output of the isolation networks 242, 248, respectively. For example, in the substrate processing system 200, the sensors 240 include a voltage sensor 240A for measuring or otherwise detecting a voltage at the edge ring 110 (e.g., at the output of the isolation network 242), and a current sensor 240B for measuring or otherwise detecting a current at the edge ring 110 (e.g., at the output of the isolation network 242). Likewise, the sensors 246 include a voltage sensor 246A for measuring or otherwise detecting a voltage at the ESC 108 (e.g., at the output of the isolation network 248), and a current sensor 240B for measuring or otherwise detecting a current at the ESC 108 (e.g., at the output of the isolation network 248).

[0079] In various embodiments, the voltage sensors 240A, 246A and the current sensors 240B, 246B in the measurement system 150 may be any suitable types of sensors. For example, the voltage sensors 240A, 246A and the current sensors 240B, 246B may include high pass filtering characteristics to strip away the RF voltages from the RF power sources 220, 238. For instance, each voltage sensor 240A, 246A may include a capacitive divider network for detecting a voltage at the ESC 108 or the edge ring 110, and each current sensor 240B, 246B may include a current transformer for detecting a current at the ESC 108 or the edge ring 110. As examples only, FIG. 11 depicts one example of a capacitive divider network 1100 that is employable as one or both voltage sensors 240A, 246A, where the capacitive divider network 1100 includes at least two capacitors 1102, 1104. FIG. 12 depicts one example of a current transformer 1200 that is employable as one or both current sensors 240B, 246B, where the current transformer 1200 includes at least two coils 1202, 1204.

[0080] In other examples, the sensors 240, 246 of FIG. 2 may measure other characteristics. For example, in some embodiments, the sensors 240, 246 may be or include directional couplers and/or bi-directional couplers to measure forward going and reflected waves, in lieu of voltage and current measurements.

[0081] With continued reference to FIG. 2, the detected voltages and currents at the ESC 108 and the edge ring 110 are fed back to and received by the controller 140. In such examples, signals representing the detected voltages and currents may pass through a filtering and digitization network. Specifically, as shown in FIG. 2, the detected voltages and currents are provided by analog signals, which pass through a filter 252 and an analog-to-digital converter (ADC) 254 before being received by the controller 140 (e.g., via a digital communication interface). With this configuration, the filter 252 includes a low-pass filter (e.g., an anti-aliasing circuit) for the analog signals, and the ADC 254 converts the analog signals into digital signals for processing by the controller 140. [0082] In the example of FIG. 2, the controller 140 may include any suitable type of processor, such as a microprocessor and/or an FPGA, etc. that communicates with the ADC 254 and performs necessary calculations to determine relative sheath thicknesses local to the ESC 108 and edge ring 110. In such examples, the calculations may include a division of each voltage to each current signal and then a de-embedding process to transform the plane of measurement to the plane of the ESC 108 and the edge ring 110 to obtain an impedance associated with each of the ESC 108 and the edge ring 110. This impedance calculation may involve complex algebra and a model of the RF power delivery path to the ESC 108 and edge ring 110. In other embodiments, the impedance calculation may involve an S parameter matrix, measured or modeled, of the RF power delivery path, or a set of S parameter matrices, measured or modeled, of the components of the RF power delivery path.

[0083] In various embodiments, the measuring branches 150A, 150B of the measurement system 150 see different reactive loads by the plasma and resulting plasma sheath formed above the substrate 112. For example, FIG. 4 depicts a scenario in which the measurement power source 152 of the measurement system 150 (e.g., the measuring branch 150A) is attached to the edge ring 1 10 with a plasma sheath 400 formed above a substrate (e.g., the substrate 112), and FIG. 5 depicts a scenario in which the measurement power source 152 of the measurement system 150 (e.g., the measuring branch 150B) is attached to the ESC 108 with the plasma sheath 400 formed above the substrate. In such examples, impedances associated with the ESC 108 and the edge ring 110 may be determined based on the sensed feedback for when the plasma sheath 400 is at or near a maximum thickness.

[0084] In the example of FIG. 4, the impedance associated with the edge ring 110 includes an impedance associated with plasma within a processing chamber capacitive coupled through the plasma sheath 400 at the edge ring 110 and an impedance associated with a capacitive coupling to the ESC 108. For example, and as shown in FIG. 4, the impedance measured includes a load comprised of the plasma load capacitive coupled through the plasma sheath 400, as well as coupling through the interelectrode capacitance to the ESC 108. In FIG. 4, the plasma load capacitive coupled through the plasma sheath 400 is represented generally by a capacitor 410 and the interelectrode capacitance to the ESC 108 is represented generally by a capacitor 420. Additionally, the impedance measured includes a load presented by the measuring branch 150B (e.g., the ESC portion of the measurement system 150) and a main bias matching network (e.g., the matching and distribution network 128 of FIG. 1 ), which is coupled through the interelectrode capacitance (e.g., the capacitor 420). In such examples, the load presented by the measuring branch 150B and the main bias matching network is represented generally by an impedance (Z) block 440.

[0085] Additionally, in the example of FIG. 5, the impedance associated with the ESC 108 includes an impedance associated with the plasma capacitive coupled through the plasma sheath 400 at the ESC 108 and an impedance associated with a capacitive coupling to the edge ring 110. For example, in FIG. 5, the impedance measured includes a load comprised of the plasma load capacitive coupled through the plasma sheath 400, as well as coupling through the interelectrode capacitance to the edge ring 110. In FIG. 5, the plasma load capacitive coupled through the plasma sheath 400 is represented generally by a capacitor 530 and the interelectrode capacitance to the ESC 108 is represented generally by a capacitor 520. Additionally, the impedance measured for the ESC 108 includes a load presented by the measuring branch 150A (e.g., the edge ring portion of the measurement system 150) and the main bias matching network (e.g., the matching and distribution network 128 of FIG. 1 ), which is coupled through the interelectrode capacitance (e.g., the capacitor 520). The load presented by the measuring branch 150A and the main bias matching network is represented generally by an impedance (Z) block 540.

[0086] With continued reference to FIG. 2, the controller 140 may utilize the impedances associated with the ESC 108 and the edge ring 110 to adjust the TES compensation. For example, in some embodiments where an equilibrium state is present, the capacitances and impedances represented in FIGS. 4-5 may be time independent. In such examples, the controller 140 can extract (e.g., via a broadband frequency measurement) the contributions to the total load impedance of the plasma sheath 400 on the ESC 108 and the edge ring 110. Then, the controller 140 may compare the impedance contributions associated with the ESC 108 and the impedance associated with the edge ring 110 to infer the quality of the current TES compensation and adjust the TES compensation based on the comparison if necessary.

[0087] In some embodiments, the impedance measurements may be taken while the TES factor is systematically varied. For example, the controller 140 may vary the TES compensation, thereby changing the RF voltage provided by the edge ring RF power source 238 to the electrode 218 in the edge ring 110. In such examples, to simply calculations, the controller 140 may treat the capacitance between the edge ring 110 and plasma sheath 400 as the only capacitance changing due to the varying TES factor. This treatment by the controller 140 is based on the theory of the thickness of the plasma sheath 400 across the broad span of the ESC 108 remaining substantially unchanged with the varying TES factor, whereas the thickness of the plasma sheath 400 near the edge of the substrate 112 may change more significantly with the varying TES factor. Therefore, in this example, the edge ring 110 located near the edge of the substrate 112 is impacted by the varying TES factor.

[0088] In various embodiments, the controller 140 may determine the impedances associated with the ESC 108 and the edge ring 110 while the TES compensation (e.g., and more generally the TES factor) is varied. In such examples, the impedances associated with the ESC 108 and the edge ring 110 may be determined (e.g., measured) multiple times over different, known TES compensations. This may result in a more accurate extraction of the edge ring 110 to plasma capacitance (e.g., the capacitance represented generally by the capacitor 410 in FIG. 4), therefore a better understanding of the quality of TES compensation.

[0089] As example only, FIG. 6 depicts a scenario in which the measurement power source 152 of the measurement system 150 (e.g., the measuring branch 150A) is attached to the edge ring 110 with the plasma sheath 400 formed above the substrate, in which the TES factor is varied. As shown, the profile of the plasma sheath 400 near the edge ring 110 changes with the varying TES factor. In this example, the plasma load capacitive coupled through the plasma sheath 400 (represented generally by a capacitor 610) is shown to change with the varying TES factor.

[0090] Likewise, FIG. 7 depicts a scenario in which the measurement power source 152 of the measurement system 150 (e.g., the measuring branch 150B) is attached to the ESC 108 with the plasma sheath 400 formed above the substrate. In this example, the TES factor is varied, causing the profile of the plasma sheath 400 near the edge ring 110 to change. In the example of FIG. 7, the plasma load capacitive coupled through the plasma sheath 400 to the edge ring 110 (represented generally by a capacitor 710) is shown to change with the varying TES factor.

[0091] In various embodiments, the measurements associated with the scenarios depicted in FIGS. 6-7 may be made in various manners. For example, these measurements can be taken independently or concurrently. Additionally, in some examples, the resulting calculations for TES compensation may involve the independent measurements or a relationship between the measurements.

[0092] With continued reference to FIG. 2, the measurement system 150 and the measurement power source 152 may be operated based on characteristics of the bias configuration, such as the frequency and/or waveform of the RF voltages provided by the RF power sources 220, 238 to the ESC 108 and the edge ring 110. For example, the bandwidth of the sensors 240, 246 of FIG. 2 can be tailored to a specific implementation of the RF power sources 220, 238. As one example, the minimum bandwidth of the sensors 240, 246 may be dictated by the measurement power source 152, such as whether the measurement power source 152 is providing a fixed frequency, low voltage signal or broadband, low voltage signal.

[0093] In various embodiments, the type of waveform of the RF voltages provided by the RF power sources 220, 238 to the ESC 108 and the edge ring 110 may alter operation of the sensors 240, 246. For example, the RF voltages applied to the ESC 108 and the edge ring 110 may be sinusoidal waveforms. In such examples, an optimal sampling period of the analog signals by the ADC 254 is during the positive portion of the sinusoidal cycle. In other examples, the RF voltages applied to the ESC 108 and the edge ring 110 may be non-sinusoidal waveforms. If so, an optimal sampling period is during the shallow negative going slope during ion current compensation. In either case, the sampling period is synchronized to the state of the RF power sources 220, 238, and the sampling period may have a beginning, duration, and end shifted relative to the beginning of the bias supply cycle to achieve optimal measurement fidelity. This may involve, for example, gating of the measurement power source 152 as to only apply the low voltage signal during the desired sampling period, and command the ADC 254 to begin acquiring digital samples of current and voltage from the sensors 240, 246 during this period. In such examples, the sampled values may be buffered and accessed by the controller 140 when desired.

[0094] Additionally, in some embodiments, it may be desirable to implement out of band rejection based on the main bias frequency. For example, the sensors 240, 246 may be operated at a frequency or in a frequency band based on the RF voltage provided to the ESC 108. In such examples, the frequency band of the sensors 240, 246 may begin and end far enough away from the lowest frequency or the highest frequency in the bias bandwidth to allow for reasonable isolation and filtering to occur. [0095] For example, in some embodiments, the RF power source 220 may provide a sinusoidal, single frequency RF bias voltage signal to the ESC 108. In such examples, the single frequency may be one specific frequency or a narrow band of frequencies. In this case, the sensors 240, 246 can operate at a frequency band less than or greater than the specific frequency or the band of frequencies. As one example, FIG. 8 depicts a graph 800 showing a sinusoidal RF bias voltage signal provided at a narrow band of frequencies having a center frequency fo. In this example, the sensors 240, 246 can operate either in a frequency band (Band 1 ) below the lowest frequency in the bias bandwidth or in a frequency band (Band 2) above the highest frequency in the bias bandwidth.

[0096] In other examples, the RF power source 220 may provide a sinusoidal, multifrequency RF bias voltage signal to the ESC 108. In such examples, the sensors 240, 246 will be provided with more possible frequency bands for operation than the single frequency bias configuration described above, but with narrower spans. In other words, the sensors 240, 246 can operate at a frequency band less than and/or greater than each specific frequency or each band of frequencies. For example, FIG. 9 depicts a graph 900 showing a sinusoidal frequency RF bias voltage signal provided at two narrow band of frequencies each having a center frequency fo, fi. In this example, the sensors 240, 246 can operate in a frequency band (Band 1 ) below the lowest frequency in the bias bandwidth centered at the frequency fo, or in a frequency band (Band 2) above the highest frequency in the bias bandwidth centered at the frequency fo and below the lowest frequency in the bias bandwidth centered at the frequency fi, or in a frequency band (Band 3) above the highest frequency in the bias bandwidth centered at the frequency fi.

[0097] In some other embodiments, the RF power source 220 may provide a non- sinusoidal, RF bias voltage signal to the ESC 108. In such examples, the total bandwidth of the bias voltage signal is considered. As such, the sensors 240, 246 can operate at a frequency band greater than the highest frequency component in the non- sinusoidal signal. For example, FIG. 10 depicts a graph 1000 showing a non-sinusoidal RF bias voltage signal having a total frequency bandwidth indicated by NS. In this example, the sensors 240, 246 can operate at a frequency band (Band) above the frequency bandwidth NS (Bias). [0098] Referring now to FIG. 13, an example method 1300 for monitoring and adjusting a TES compensation in a substrate processing system is depicted. While FIG. 13 is shown and described as including specific steps, it should be appreciated that the method 1300 is an example variation that may be implemented and in other embodiments the method 1300 and/or other example methods may include different steps, more or less steps, etc. Additionally, although the method 1300 is described in relation to the systems 100, 200 of FIGS. 1 -2, the method 1300 may be employable by any suitable system.

[0099] As shown, the method 1300 begins at 1302, where a substrate is arranged on a substrate support in a processing chamber in any suitable manner. Then, at 1304 plasma processing (e.g., a plasma etch step) is performed on the substrate by, for example, at least supplying RF voltage signals to an edge ring and an ESC of the substrate support. The method 1300 then proceeds to 1306.

[0100] At 1306, the method 1300 (e.g., the controller 140) determines whether to initiate edge ring compensation monitoring. If no, the method 1300 proceeds to 1308, where the method 1300 (e.g., the controller 140) determines whether the plasma processing is complete. If so, the method 1300 ends as shown in FIG. 13. If not, the method 1300 returns to 1304. If, however, the controller 140 determines to initiate edge ring compensation monitoring at 1306, the method 1300 proceeds to 1310.

[0101] At 1310, an additional RF voltage is provided to the edge ring and the ESC of the substrate support. In such examples, the RF voltage is a low voltage signal provided by a dedicated measurement power source (e.g., the measurement power source 152) that is in addition to the RF voltages supplied to the edge ring and the ESC for the plasma processing performed at 1304. In various embodiments, the measurement power source may be controlled by the controller 140 to provide the low voltage signal at a fixed or varying frequency and at a desired time with respect to the RF voltage signals applied to the ESC and the edge ring. The method 1300 then proceeds to 1312.

[0102] At 1312, voltage and current values at the edge ring and the ESC are received by the controller 140. For instance, sensors may detect analog voltage and current values at the edge ring and the ESC and pass the analog values to an ADC (e.g., the ADC 254). The analog values may then be sampled to generate digital values for the controller 140, as explained herein. The method 1300 then proceeds to 1314. [0103] At 1314, the method 1300 (e.g., the controller 140) determines impedances associated with the ESC and the edge ring based on the received voltage and current values. Such impedances represent the effective reactive loads on the ESC and the edge ring by the plasma and resulting plasma sheath. Then, at 1316 the method 1300 (e.g., the controller 140) analyzes the determined impedances. For example, the controller 140 may compare the impedance contributions associated with the ESC and the edge ring to infer the quality of a current TES compensation. The method 1300 then proceeds to 1318.

[0104] At 1318, the method 1300 (e.g., the controller 140) determines whether to adjust the current TES compensation. For example, if the current TES compensation causes a condition (e.g., a profile, ion trajectory, etc.) associated with the plasma sheath to exceed a threshold, the controller 140 may determine that an adjustment to the current TES compensation is desired. If so, the method 1300 proceeds to 1320. Otherwise, if the controller 140 determines that no adjustment to the current TES compensation is necessary, the method 1300 returns to 1308.

[0105] At 1320, the TES compensation is adjusted. For example, the TES compensation may be adjusted based on one or more determined impedances associated with the ESC and the edge ring. In some examples, impedances associated with the ESC and the edge ring may be determined multiple times as the edge ring begins to erode and/or while a TES factor is varied. Then, the multiple impedances associated with the ESC and the edge ring may be employed to generate a learned TES compensation (e.g., via a model). The method 1300 then proceeds to 1322.

[0106] At 1322, the RF voltage signal supplied to the edge ring is controlled based on the adjusted TES compensation to adjust a profile of the plasma sheath. In such examples, the controller 140 may control an RF power source (e.g., the RF power sources 238, an RF power source in the TES bias system 138, etc.) to provide an altered RF voltage based on the adjusted TES compensation, thereby changing the TES factor. The method 1300 then returns to 1306 as shown in FIG. 13.

[0107] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.

[0108] Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

[0109] In some implementations, a controller is part of a system, which may be part of the above-described examples. Such systems can comprise semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and/or specific processing components (a wafer pedestal, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. The controller, depending on the processing requirements and/or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and/or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and/or load locks connected to or interfaced with a specific system.

[0110] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and/or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and/or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.

[0111] The controller, in some implementations, may be a part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and/or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0112] Without limitation, example systems may include a plasma etch 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 etch 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 etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and/or manufacturing of semiconductor wafers.

[0113] As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and/or load ports in a semiconductor manufacturing factory.

Claims

CLAIMS What is claimed is:

1 . A system comprising: a substrate support positioned within a substrate processing chamber, the substrate support including an electrostatic chuck and an edge ring positioned about the electrostatic chuck; an edge ring RF power source configured to provide an RF voltage to the edge ring based on a tuning edge sheath compensation during processing of a substrate in the substrate processing chamber; a measurement power source configured to provide an RF voltage to the electrostatic chuck and the edge ring; and a controller in communication with at least the edge ring RF power source and the measurement power source, the controller configured to: determine an impedance associated with the electrostatic chuck and an impedance associated with the edge ring based on the RF voltage provided to the electrostatic chuck and the edge ring from the measurement power source; adjust the tuning edge sheath compensation based on the impedance associated with the electrostatic chuck and the impedance associated with the edge ring; and control the edge ring RF power source to adjust the RF voltage based on the adjusted tuning edge sheath compensation.

2. The system of claim 1 , further comprising one or more sensors configured to detect a voltage and a current at the edge ring, wherein the controller is configured to receive the voltage and the current, and determine the impedance associated with the edge ring based on the voltage and the current.

3. The system of claim 2, further comprising an isolation network coupled between the measurement power source and the edge ring.

4. The system of claim 3, further comprising a power amplifier coupled between the isolation network and the measurement power source.

5. The system of claim 2, wherein: the one or more sensors are configured to detect a voltage and a current at the electrostatic chuck; and the controller is configured to receive the voltage and the current at the electrostatic chuck, and determine the impedance associated with the electrostatic chuck based on the voltage and the current at the electrostatic chuck.

6. The system of claim 5, further comprising an isolation network coupled between the measurement power source and electrostatic chuck.

7. The system of claim 6, further comprising a power amplifier coupled between the isolation network and the measurement power source.

8. The system of claim 5, further comprising an RF power source configured to provide an RF voltage to the electrostatic chuck, wherein the one or more sensors are configured to operate at a frequency based on the RF voltage provided to the electrostatic chuck.

9. The system of claim 8, wherein: the RF power source is configured to provide a sinusoidal RF voltage to the electrostatic chuck at one or more frequencies; and wherein the one or more sensors are configured to operate at a frequency band less than or greater than the one or more frequencies of the sinusoidal RF voltage.

10. The system of claim 8, wherein: the RF power source is configured to provide a non-sinusoidal RF voltage to the electrostatic chuck; and the one or more sensors are configured to operate at a frequency band greater than a highest frequency of the non-sinusoidal RF voltage.

11 . The system of claim 2, wherein the one or more sensors include a capacitive divider network to detect the voltage.

12. The system of claim 2, wherein the one or more sensors include a current transformer to detect the current.

13. The system of claim 1 , wherein the controller is configured to determine the impedance associated with the electrostatic chuck and the impedance associated with the edge ring when a plasma sheath formed within the substrate processing chamber is at or near a maximum thickness.

14. The system of claim 1 , wherein the impedance associated with the edge ring includes an impedance associated with plasma within the substrate processing chamber capacitive coupled through a plasma sheath at the edge ring and an impedance associated with a capacitive coupling to the electrostatic chuck.

15. The system of claim 14, wherein the impedance associated with the electrostatic chuck includes an impedance associated with the plasma within the substrate processing chamber capacitive coupled through the plasma sheath at the electrostatic chuck and an impedance associated with a capacitive coupling to the edge ring.

16. The system of claim 15, wherein the controller is configured to compare the impedance associated with the electrostatic chuck and the impedance associated with the edge ring, and adjust the tuning edge sheath compensation based on the comparison.

17. The system of claim 1 , wherein the controller is configured to: vary the tuning edge sheath compensation; and determine the impedance associated with the electrostatic chuck and the impedance associated with the edge ring while the tuning edge sheath compensation is varied.

18. The system of claim 1 , wherein the RF voltage provided to the electrostatic chuck and the edge ring from the measurement power source is five volts or less.

19. The system of claim 1 , wherein the measurement power source is configured to provide the RF voltage to the electrostatic chuck and the edge ring at a fixed frequency or a variable frequency.

20. The system of claim 1 , further comprising an RF power source configured to provide an RF voltage to the electrostatic chuck.

21 . A method comprising: providing, with an edge ring RF power source, an RF voltage to an edge ring positioned about an electrostatic chuck in a substrate processing chamber based on a tuning edge sheath compensation; providing, with a measurement power source, an RF voltage to the electrostatic chuck and the edge ring; determining an impedance associated with the electrostatic chuck and an impedance associated with the edge ring based on the RF voltage provided to the electrostatic chuck and the edge ring from the measurement power source; adjusting the tuning edge sheath compensation based on the impedance associated with the electrostatic chuck and the impedance associated with the edge ring; and controlling the edge ring RF power source to adjust the RF voltage based on the adjusted tuning edge sheath compensation.

22. The method of claim 21 , wherein: the method further comprises detecting, with one or more sensors, a voltage and a current at the edge ring and a voltage and a current at the electrostatic chuck; and determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring includes determining the impedance associated with the electrostatic chuck based on the voltage and the current at the electrostatic chuck, and the impedance associated with the edge ring based on the voltage and the current at the edge ring.

23. The method of claim 22, wherein: the method further comprises providing, with an RF power source, an RF voltage to the electrostatic chuck; and detecting, with one or more sensors, the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck includes detecting the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck at a frequency based on the RF voltage provided to the electrostatic chuck.

24. The method of claim 23, wherein: providing the RF voltage to the electrostatic chuck includes providing a sinusoidal RF voltage to the electrostatic chuck at one or more frequencies; and detecting, with one or more sensors, the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck includes detecting the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck at a frequency band less than or greater than the one or more frequencies of the sinusoidal RF voltage.

25. The method of claim 23, wherein: providing the RF voltage to the electrostatic chuck includes providing a non- sinusoidal RF voltage to the electrostatic chuck; and detecting, with one or more sensors, the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck includes detecting the voltage and the current at the edge ring and the voltage and the current at the electrostatic chuck at a frequency band greater than a highest frequency of the non-sinusoidal RF voltage.

26. The method of claim 21 , wherein determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring includes determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring when a plasma sheath formed within the substrate processing chamber is at or near a maximum thickness.

27. The method of claim 21 , wherein the impedance associated with the edge ring includes an impedance associated with plasma within the substrate processing chamber capacitive coupled through a plasma sheath at the edge ring and an impedance associated with a capacitive coupling to the electrostatic chuck.

28. The method of claim 27, wherein the impedance associated with the electrostatic chuck includes an impedance associated with the plasma within the substrate processing chamber capacitive coupled through the plasma sheath at the electrostatic chuck and an impedance associated with a capacitive coupling to the edge ring.

29. The method of claim 28, wherein: the method further comprises comparing the impedance associated with the electrostatic chuck and the impedance associated with the edge ring; and adjusting the tuning edge sheath compensation includes adjusting the tuning edge sheath compensation based on the comparison.

30. The method of claim 21 , wherein: the method further comprises varying the tuning edge sheath compensation; and determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring includes determining the impedance associated with the electrostatic chuck and the impedance associated with the edge ring while the tuning edge sheath compensation is varied.