Systems and methods for real-time pulse measurements and pulse timing adjustments to control plasma processing performance

Abstract

Various embodiments of systems and methods for controlling a pulsed plasma are described herein. Pulse timing parameters (e.g., pulse on time and / or pulse off time) of a plasma generating source can be controlled based on measurement data received from a measurement device to control plasma exposure of a substrate during a sequence of dynamically controlled pulses in a plasma processing chamber. Additionally or alternatively, pulse timing parameters (e.g., pulse on time and / or pulse off time) can be applied to source power, bias power, and / or both based on measurement data received from a measurement device to control plasma exposure of the substrate. Pulse timing changes can be made in a feedforward or feedback manner.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Non-Provisional Patent Application No. 17 / 318,116, filed May 12, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to the processing of substrates in plasma processing apparatuses, and more particularly to systems and methods for monitoring and adjusting pulse timing of plasma generated within the plasma processing apparatus. [Background technology]

[0003] The use of plasma systems for processing substrates (such as semiconductor wafers) is well known. Plasma processing systems are often utilized in plasma etching and / or plasma deposition processes. For example, plasma processing systems may be used to etch substrates to form microelectronic or micromechanical devices. Plasma processing systems generate plasma by applying radio frequency power to a gas mixture within a plasma processing chamber to ionize the gas within the plasma processing chamber. Conventional hardware and processing techniques can result in non-uniform ion or plasma density distribution across the substrate. Furthermore, conventional systems may not achieve sufficient plasma density under certain processing conditions and / or certain plasma gases. Summary of the Invention [Problem to be solved by the invention]

[0004] Plasma processing presents many technical challenges, and plasma control becomes increasingly important as the geometries of structures and layers on a substrate become smaller. Plasma processing performance is affected by many variables, including plasma species, plasma density, ion kinetic energy, and reactive neutrals. Plasma characteristics can be altered to achieve desired processing performance by adjusting variable settings on a plasma processing system. These settings include, but are not limited to, gas flow rates, gas pressures, plasma excitation power, and bias voltages, all of which are known in the art. Because these settings are not directly related to plasma characteristics, control of the plasma characteristics to achieve desired processing performance is often an issue. As substrate processing requirements become increasingly stringent, improved control of plasma characteristics is needed.

[0005] Plasma control optimization is performed through a dynamically controlled sequence of processing steps, and control methods are essential for maintaining uniformity of plasma distribution, profile control, and plasma density profiles under constantly changing conditions at the substrate surface. Conventional hardware and processing techniques do not provide sufficient mechanisms for responsively controlling plasma during an etching or deposition processing sequence. The problems of fixed plasma parameter settings can be exacerbated by specific system architectures or the use of specific etching gas chemistries in specific applications. Conventional systems are not well-suited to provide a consistently stable and optimal plasma field under these conditions. As a result, product quality and throughput can be compromised. [Means for solving the problem]

[0006] Various embodiments of systems and methods for controlling pulsed plasma are described herein. Pulse timing parameters (e.g., pulse on time and / or pulse off time) of a plasma generating source can be controlled based on measurement data received from a measurement device to control plasma exposure of a substrate during a sequence of dynamically controlled pulses in a plasma processing chamber. Additionally or alternatively, pulse timing parameters (e.g., pulse on time and / or pulse off time) can be applied to source power, bias power, and / or both based on measurement data received from the measurement device to control plasma exposure of the substrate. Pulse timing changes can be made in a feedforward or feedback manner.

[0007] According to one embodiment, provided herein is a method for controlling plasma performance in a system for processing a substrate, the system including one or more power sources. Generally, the method may include providing a first power signal from one or more power sources to a plasma processing chamber and providing a second power signal from the one or more power sources to the plasma processing chamber to generate a plasma in the plasma processing chamber for processing the substrate using a pulsed plasma process. The first power signal may include a first set of timing parameters specifying a pulse-on time and a pulse-off time of the first power signal. Similarly, the second power signal may include a second set of timing parameters specifying a pulse-on time and a pulse-off time of the second power signal. The method may also include generating measurement data corresponding to the first power signal, the second power signal, the plasma, and / or the chamber pressure, the measurement data being generated in real time during the pulsed plasma process. Further, the method may include adjusting, in response to the measurement data, one or more timing parameters of the first power signal, one or more timing parameters of the second power signal, and / or the chamber pressure to modify a pulse width of the first power signal and / or a pulse width of the second power signal to control one or more characteristics of the plasma during the plasma processing.

[0008] In some embodiments, providing the first power signal and providing the second power signal may include providing the first power signal and the second power signal from a single power source. In other embodiments, providing the first power signal may include providing the first power signal from a first power source, and providing the second power signal may include providing the second power signal from a second power source different from the first power source.

[0009] In some embodiments, generating the measurement data may include generating in-situ measurement data. For example, generating the measurement data may include measuring one or more of an optical intensity or an optical emission spectrum of a plasma generated in a plasma processing chamber and / or a direct current voltage (Vdc) level of a plasma generated in a plasma processing chamber.

[0010] In some embodiments, generating the measurement data may include generating off-device measurement data. For example, generating the measurement data may include measuring one or more of the power, voltage, current, and / or phase of a first power signal, the power, voltage, current, and / or phase of a second power signal, and the power, voltage, current, and / or phase of at least one harmonic of the first power signal and / or the second power signal. In some embodiments, generating the measurement data may include measuring the power level of a fundamental frequency and the voltages, currents, and phases of up to five harmonics of the first power source and the second power source. In such embodiments, the generated measurement data may be selectively used individually or in combination.

[0011] The one or more characteristics of the plasma that are controlled while adjusting the one or more timing parameters may include, but are not limited to, the plasma density, electron temperature, gas dissociation, etch material selectivity, ion flux, and / or ion energy of the plasma.

[0012] In some embodiments, the first power signal may be a source power signal, and the adjusting may include adjusting a pulse-on time of the first power signal to control a plasma density of the plasma. In one example embodiment, the adjusting may include adjusting the pulse-on time of the first power signal in real time during a cycle of pulsed plasma processing based on measurement data generated during the cycle. For example, generating the measurement data may include detecting a rising edge of the first power signal during a cycle of pulsed plasma processing, and the adjusting may include adjusting a falling edge of the first power signal during the cycle of pulsed plasma processing to control the pulse-on time of the first power signal to maintain a predetermined plasma density.

[0013] In some embodiments, the second power signal may be a bias power signal, and the adjusting may include adjusting a pulse-on time of the second power signal to control ion flux and / or ion energy of the plasma. In one example embodiment, the adjusting may include adjusting the pulse-on time of the second power signal in real time during a cycle of pulsed plasma processing based on measurement data generated during the cycle. For example, generating the measurement data may include detecting a rising edge of the second power signal during each cycle of pulsed plasma processing, and the adjusting may include adjusting a falling edge of the second power signal during each cycle of pulsed plasma processing to control the pulse-on time of the second power signal to maintain a predetermined ion flux and / or ion energy.

[0014] In some embodiments, if the pulse-on time of the second power signal is adjusted during a current cycle of the pulsed plasma treatment, the adjusting may further include adjusting the pulse-on time and the pulse-off time of the second power signal in a next cycle of the pulsed plasma treatment based on the adjustment made during the current cycle.

[0015] In some embodiments, the adjusting can be performed to control the relative timing of the first power signal and the second power signal, for example, to control the time difference between a pulse-off time of the first power signal and a pulse-on time of the second power signal.

[0016] In some embodiments, generating the measurement data may include using a single measurement device to measure pulses in the plasma from a train of multiple plasma pulses provided to the plasma processing chamber.

[0017] In some embodiments, generating the measurement data may include measuring an optical emission spectrum of the plasma while measuring (a) the power, voltage, or current of the first power signal, (b) the power, voltage, or current of the second power signal, and / or (c) the power, voltage, or current of a harmonic of the first power signal or the second power signal. In such embodiments, the method may further include comparing the optical emission spectrum of the plasma to (a) the power, voltage, or current of the first power signal, (b) the power, voltage, or current of the second power signal, or (c) the power, voltage, or current of a harmonic of the first power signal or the second power signal.

[0018] In some embodiments, generating the measurement data can include measuring a chamber pressure in a plasma processing chamber, and in such embodiments, adjusting can include adjusting the chamber pressure during plasma processing to control one or more properties of the plasma.

[0019] According to another embodiment, a system for processing a substrate is provided herein. The system may generally include a plasma processing chamber, one or more power sources, one or more measurement devices, and a controller. The plasma processing chamber may generally be configured to process a substrate using pulsed plasma processing. The one or more power sources may be coupled to provide a first power signal and a second power signal to the plasma processing chamber to generate a plasma within the plasma processing chamber. As described above, the first power signal may include a first set of timing parameters specifying a pulse-on time and a pulse-off time of the first power signal, and the second power signal may include a second set of timing parameters specifying a pulse-on time and a pulse-off time of the second power signal. In some embodiments, the first power signal and the second power signal may be provided by a single power source. In other embodiments, the first power signal may be provided by a first power source and the second power signal may be provided by a second power source different from the first power source.

[0020] The one or more measurement devices may be configured to generate measurement data corresponding to the first power signal, the second power signal, the plasma, or the chamber pressure, and the measurement data may be generated in real time during the pulsed plasma process in the plasma processing chamber. In some embodiments, the measurement data generated by the one or more measurement devices may include one or more of: (a) the power, voltage, current, and / or phase of the first power signal, (b) the power, voltage, or current of harmonics of the first power signal, (c) the power, voltage, current, and / or phase of the second power signal, (d) the power, voltage, or current of harmonics of the second power signal, (e) the optical intensity or emission spectrum of the plasma generated in the plasma processing chamber, (f) the direct current voltage (Vdc) level of the plasma generated in the plasma processing chamber, and (g) the chamber pressure in the plasma processing chamber.

[0021] A controller can be coupled to the one or more power sources and the one or more measurement devices. In response to the measurement data, the controller can be configured to adjust one or more timing parameters of the first power signal, the second power signal, and / or the chamber pressure to modify a pulse width of the first power signal and / or a pulse width of the second power signal to control one or more plasma properties during plasma processing.

[0022] In some embodiments, the first power signal may be a source power signal, and the controller may be configured to adjust the pulse-on time of the first power signal to control the plasma density of the plasma. In one example embodiment, the controller may be configured to adjust the pulse-on time of the first power signal in real time during a cycle of pulsed plasma processing based on measurement data generated during the cycle by one or more measurement devices. For example, the one or more measurement devices may be configured to detect a rising edge of the first power signal during the cycle of pulsed plasma processing. Based on the rising edge of the first power signal detected by the one or more measurement devices, the controller may be configured to adjust a falling edge of the first power signal during the cycle of pulsed plasma processing to control the pulse-on time of the first power signal to maintain a predetermined plasma density.

[0023] In some embodiments, the second power signal may be a bias power signal, and the controller may be configured to adjust the pulse-on time of the second power signal to control the ion flux and / or ion energy of the plasma. In one example embodiment, the controller may be configured to adjust the pulse-on time of the second power signal in real time during a cycle of pulsed plasma processing based on measurement data generated during the cycle. For example, the one or more measurement devices may be configured to detect a rising edge of the second power signal during a cycle of pulsed plasma processing. Based on the rising edge of the second power signal detected by the one or more measurement devices, the controller may be configured to adjust a falling edge of the second power signal during the cycle of pulsed plasma processing to control the pulse-on time of the second power signal to maintain a predetermined ion flux and / or ion energy.

[0024] In some embodiments, when the pulse-on time of the second power signal is adjusted during a current cycle of the pulsed plasma treatment, the controller may be further configured to adjust the pulse-on time and the pulse-off time of the second power signal in a next cycle of the pulsed plasma treatment based on the adjustment made during the current cycle.

[0025] In some embodiments, the one or more measurement devices may be configured to measure a chamber pressure in the plasma processing chamber during pulsed plasma processing, and the controller may be configured to adjust the chamber pressure during pulsed plasma processing to maintain a specified plasma density, ion flux, and / or ion energy.

[0026] According to yet another embodiment, another system for processing a substrate is provided, the system including a plasma processing chamber, a first power supply, a second power supply, one or more measurement devices, and a controller. The plasma processing chamber may generally be configured to process the substrate using pulsed plasma processing and may include a first power supply system and a second power supply system. The first power supply may be coupled to supply a first power signal to the first power supply system to generate a plasma in the plasma processing chamber, and the second power supply may be coupled to supply a second power signal to the second power supply system. As described above, the first power signal may include a first set of timing parameters specifying a pulse-on time and a pulse-off time of the first power signal, and the second power signal may include a second set of timing parameters specifying a pulse-on time and a pulse-off time of the second power signal.

[0027] The one or more measurement devices may be configured to generate measurement data in real time during the pulsed plasma process in the plasma processing chamber. In some embodiments, the measurement data may include (a) off-instrument measurement data corresponding to the first power signal and / or the second power signal, and (b) on-instrument measurement data corresponding to the plasma or chamber pressure in the plasma processing chamber. For example, the off-instrument measurement data may include one or more of the power, voltage, current, and / or phase of the first power signal, the power, voltage, or harmonic current of the first power signal, the power, voltage, current, and / or phase of the second power signal, and the power, voltage, or harmonic current of the second power signal. Similarly, the on-instrument measurement data may include one or more of the optical intensity or emission spectrum of the plasma generated in the plasma processing chamber, the direct current voltage (Vdc) level of the plasma generated in the plasma processing chamber, and the chamber pressure in the plasma processing chamber.

[0028] A controller can be coupled to the first power supply, the second power supply, and the one or more measurement devices. In response to the measurement data, the controller can be configured to adjust one or more timing parameters of the first power signal, one or more timing parameters of the second power signal, and / or the chamber pressure to modify a pulse width of the first power signal and / or a pulse width of the second power signal to control one or more plasma properties during plasma processing.

[0029] Different or additional features, variations, and embodiments may be implemented, and related systems and methods may be utilized.

[0030] A more complete understanding of the present invention and its advantages will be obtained by referring to the following description in conjunction with the accompanying drawings, in which like reference numerals indicate like features, and in which it is to be noted, however, that the accompanying drawings illustrate only exemplary embodiments of the disclosed concepts and are not intended to limit the scope of the invention, as the disclosed concepts may encompass other embodiments that are equally effective. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a block diagram illustrating an exemplary plasma processing system. [Figure 2A] 1 is a block diagram illustrating an exemplary embodiment of a system for controlling plasma processing performance of a plasma processing system. [Figure 2B] FIG. 2 is a block diagram illustrating another exemplary embodiment of a system for controlling plasma processing performance of a plasma processing system. [Figure 3A] FIG. 2 is a block diagram illustrating another embodiment of a system for controlling plasma processing performance of a plasma processing system. [Figure 3B] 1, 2A-2B, and 3A. FIG. 2 is a graph illustrating example measurement data that may be obtained from one or more measurement devices that may be included in any of the systems shown in FIGS. [Figure 4] FIG. 2 is a block diagram illustrating a control loop for controlling plasma processing performance. [Figure 5]1 is a graph illustrating various timing parameters that correspond to power signals that can be supplied to a plasma processing chamber or measured plasma parameters. [Figure 6] 10 is a graph illustrating various control methods that may be used to adjust one or more timing parameters of a power signal supplied to a plasma processing chamber in accordance with techniques described herein. [Figure 7] FIG. 1 is a flow diagram illustrating one embodiment of a method for controlling plasma performance in accordance with techniques described herein. DETAILED DESCRIPTION OF THE INVENTION

[0032] Various embodiments of systems and methods for controlling plasma processing performance of a plasma processing system are provided herein. Systems according to the present disclosure may include one or more power sources that generate one or more power signals. In some embodiments, one power source can be used to generate the one or more power signals. In other embodiments, two or more power sources can be used to generate the two or more power signals. In one exemplary embodiment, the system may include a first power source coupled to provide a first power signal to a plasma processing chamber to generate a plasma therein, and a second power source coupled to provide a second power signal to the plasma processing chamber. The system may also include one or more measurement devices coupled to generate measurement data corresponding to the first power signal, the second power signal, or the plasma, and a controller coupled to utilize the measurement data generated by the measurement devices to control various characteristics of the plasma generated in the plasma processing chamber. The measurement data may be generated by the measurement devices and provided to the controller in real time during a plasma process in the plasma processing chamber. By utilizing the real-time data, the controller may be configured to adjust one or more parameters of the first power source and / or the second power source in real time to control the performance of the plasma process.

[0033] In some embodiments, the first power supply and the second power supply may be configured to generate a power signal with a set of parameters (e.g., amplitude, frequency, phase, pulse-on time, pulse-off time, etc.) that can be varied depending on system requirements and plasma performance. In one embodiment, the first power supply may be configured to provide source power with a first set of parameters and the second power supply may be configured to provide bias power with a second set of parameters to the plasma processing chamber. The first set of parameters and the second set of parameters may be specified in a power recipe stored in the controller.

[0034] In other embodiments, the first power supply may be configured to generate multiple power signals with a set of parameters (e.g., amplitude, frequency, phase, pulse-on time, pulse-off time, etc.) that can be varied depending on system requirements and plasma performance. In one embodiment, the first power supply may be configured to provide source power according to a first set of parameters and bias power according to a second set of parameters to the plasma processing chamber. The first set of parameters and the second set of parameters may be specified in a power recipe stored in the controller.

[0035] In a preferred embodiment, the controller can adjust one or more timing parameters of the source power (e.g., pulse-on time and / or pulse-off time) based on the measurement data received from the measurement device to control the plasma density of the plasma generated in the plasma processing chamber. Additionally or alternatively, the controller can adjust one or more timing parameters of the bias power (e.g., pulse-on time and / or pulse-off time) based on the measurement data received from the measurement device to control the ion flux and / or ion energy of the generated plasma. Other parameters of the source power and / or bias power (e.g., amplitude, frequency, phase, etc.) can also be adjusted by the controller based on the measurement data to control various characteristics of the generated plasma.

[0036] In one embodiment, the power pulse shape and phase relationship between two pulses in a multiphase pulse pattern of a pulsed plasma system can be controlled. The two pulses can be supplied from a single power supply system or from two or more power supply systems, such as a source power supply and a bias power supply. Varying the pulse shape and phase can include modifying the pulse on-time and / or pulse off-time. This variation can be performed using feedforward real-time adjustments based on data from system measurement devices that provide real-time information about the plasma and process operation. In some embodiments, feedback control can be used to vary the pulse shape and phase to control subsequent pulses. In other embodiments, both feedforward and feedback control can be used together. The pulse shape and variation can also include amplitude variation. Through pulse shape variation, plasma exposure of the substrate during a dynamically controlled sequence of pulses maintains and / or modifies plasma density, total ion flux, and energy throughout the sequence of pulses. Thus, real-time pulse timing control can be achieved with the ability to automatically adjust parameters during the etch process. Such techniques can compensate for a wide range of effects, such as the effects of substrate loading during the etching step, variations in chamber conditions, electrical variations in the power system from substrate to substrate, and variations in gas flow.

[0037] The techniques described herein may be utilized in a variety of plasma processing systems, for example, in a plasma etch processing system, a plasma deposition processing system, or any other plasma processing system.

[0038] FIG. 1 provides an example embodiment of a plasma processing system 100 that can be used in connection with the disclosed techniques and is provided for illustrative purposes only. While the plasma processing system 100 shown in FIG. 1 is a capacitively coupled plasma (CCP) processing system, those skilled in the art will recognize that the techniques described herein can be performed with an inductively coupled plasma (ICP) processing system, a microwave plasma processing system, a radial line slot antenna (RLSA™) microwave plasma processing system, an electron cyclotron resonance (ECR) plasma processing system, or other types of processing systems or combinations of systems. For example, a plasma processing system having only a single power supply may be used. Thus, those skilled in the art will recognize that the techniques described herein can be utilized with any of a variety of plasma processing systems. The plasma processing system 100 shown in FIG. 1 can also be used for a variety of operations, including, but not limited to, etching, deposition, cleaning, plasma polymerization, plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), and the like.

[0039] 1 , plasma processing system 100 includes a plasma processing chamber 105 for plasma processing a substrate 110. Plasma processing chamber 105 may be a pressure-controlled chamber, as known in the art. Substrate 110 (e.g., a semiconductor wafer) may be held on a stage or chuck 115 disposed within plasma processing chamber 105. In some embodiments, substrate 110 may be surrounded by a focus ring (not shown). The use of focus rings in plasma processing is well known. For example, when substrate 110 is a wafer, the focus ring is typically an annular structure that surrounds the wafer. The focus ring serves to confine the plasma (e.g., plasma 160), improves discontinuities in bias potential on the wafer surface due to fringing effects, and helps achieve uniform and good plasma processing around the periphery of the wafer.

[0040] The plasma processing chamber 105 may include an upper electrode 120 and a lower electrode 125, as shown in FIG. 1 . While the lower electrode 125 and the chuck 115 are depicted as separate elements, it will be appreciated that they may be formed as an integrated unit. Furthermore, while the upper electrode 120 is depicted as a single element, it will be appreciated that it may be implemented as a power supply system including multiple power coupling elements (e.g., multiple antennas). As such, the term “electrode” will be used herein to refer to a single coupling element or power transmission system including multiple power coupling elements. Furthermore, although not shown, it will be appreciated that various gas injection system mechanisms, such as a gas showerhead, may also be provided to supply process gases to the plasma processing chamber 105.

[0041] 1, the upper electrode 120 is electrically coupled to a first power supply 130 through a first matching network 155, and the lower electrode 125 is electrically coupled to a second power supply 140 through a second matching network 157. In some embodiments, the first power supply 130 provides the first matching network 155 with an upper frequency (f U ) source voltage 135, and the second power supply 140 provides a second matching network 157 with a lower frequency (f L ) bias voltage 145. In some embodiments, a voltage (not shown) can also be applied to the chuck 115.

[0042] In some embodiments, the first matching network 155 and the second matching network 157 can improve the transfer of power from the first and second power sources to the plasma 160 generated in the plasma processing chamber 105 by reducing reflected power. Matching network topologies (e.g., L-type, π-type, T-type, etc.) and automatic control methods are known to those skilled in the art. In some embodiments, the first and second power sources can be radio frequency (RF) power sources. When implemented as RF power sources, the first and second power sources can be configured to provide RF power of one or more frequencies to the upper and lower electrodes. The first and second power sources can be implemented as continuous wave sources or pulsed sources, as known in the art.

[0043] The elements of the plasma processing system 100 shown in FIG. 1 are connectable to and controllable by a control unit 170, which is connectable to corresponding memory storage units (not shown) and a user interface (not shown). Various plasma processing operations can be performed via the user interface, and various plasma processing recipes and operations can be stored in the memory storage unit. Accordingly, a given substrate using a variety of microfabrication technologies can be processed in the plasma processing chamber 105. It will be appreciated that the control unit 170 may be coupled to receive inputs from and provide outputs to various elements of the plasma processing system 100. For example, the control unit 170 may be coupled to multiple elements in the plasma processing chamber 105, the first power supply 130, the second power supply 140, the first matching network 155, and the second matching network 157. The control unit 170 may also be coupled to various sensors and measurement devices that may be included in the plasma processing system 100.

[0044] The control unit 170 can be implemented in a variety of ways. In one example, the control unit 170 can be a computer. In another example, the control unit can include one or more programmable integrated circuits programmed to provide the functionality described herein. For example, one or more processors (e.g., microprocessors, microcontrollers, central processing units, etc.), programmable logic devices (e.g., complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs), etc.), and / or other programmable integrated circuits can be programmed with software or other programming instructions to implement the functionality of a plasma processing recipe. It is further noted that the software or other programming instructions can be stored on one or more non-transitory computer-readable media (e.g., memory storage devices, flash memory, dynamic random access memory (DRAM), reprogrammable storage devices, hard drives, floppy disks, DVDs, CD-ROMs, etc.) and executed by the programmable integrated circuits to cause the programmable integrated circuits to perform the processes, functions, and / or capabilities described herein. Other variations can also be implemented.

[0045] During operation, the plasma processing system 100 generates a plasma 160 within the plasma processing chamber 105 by applying power from a first RF power source 130 and a second RF power source 140 to the upper and lower electrodes, respectively. In some cases, an edge power source (not shown) may be used to apply power to the body of the plasma processing chamber 105. The application of power creates a radio frequency electric field between the upper electrode 120 and the lower electrode 125, which dissociates and converts process gases delivered to the plasma processing chamber 105 into plasma 160. The generated plasma 160 can be used to process a target substrate (e.g., substrate 110 or any material to be processed) in various types of processes, such as, but not limited to, plasma etching, deposition, and / or sputtering.

[0046] 1, two RF power sources are used to generate a radio frequency electric field within the plasma processing chamber 105. In some embodiments, the first RF power source 130 generates a relatively high frequency (f U ), while the second RF power supply 140 provides a bias power to control the ion flux and ion energy of the generated plasma. As is known in the art, the source power and bias power may each be applied continuously to generate a continuous wave (CW) plasma, or pulsed to generate a pulsed plasma in the plasma processing chamber 105. A pulsed plasma can be generated by modulating the time, amplitude, and / or phase of the source power and / or bias power.

[0047] In some embodiments, pulsed plasma processing can be performed in the plasma processing chamber 105 by pulsing the source voltage 135 supplied to the upper electrode 120 and the bias voltage 145 supplied to the lower electrode 125. For example, the control unit 170 (or another pulse signal control device) may pulse the source voltage 135 output from the first RF power supply 130 and / or the bias voltage 145 output from the second RF power supply 140 between an off state and an on state at a desired pulse frequency and duty cycle. By modulating the source voltage 135 and / or the bias voltage 145 (i.e., varying the pulse frequency and / or duty cycle), plasma characteristics significantly different from those generated with continuous wave (CW) plasma can be obtained. For example, RF power modulation of the source voltage 135 can be used to control the time-averaged plasma density. Similarly, RF power modulation of the bias voltage 145 can be used to control the time-averaged ion flux and ion energy.

[0048] In one implementation, the first RF power supply 130 may be configured to supply a source power of approximately 0 to 3000 W to the upper electrode 120 in a high frequency range of approximately 3 MHz to 150 MHz (or higher), and the second RF power supply 140 may be configured to supply a bias power of approximately 0 to 1400 W to the lower electrode 125 in a low frequency (LF) range of approximately 0.2 MHz to 60 MHz. In some embodiments, the source power provided by the first RF power supply 130 may be a pulsed RF power signal having a duty cycle of 0% to 100%, and the bias power provided by the second RF power supply 140 may be a pulsed RF power signal having a duty cycle of 0% to 100%. The first RF power supply 130 and the second RF power supply 140 can operate as continuous wave (CW) or pulsed sources. The source and bias power supplies can also be pulsed at multiple levels of power with varying duty cycles. Different operating ranges may be used depending on the type of plasma processing system and the type of process (eg, etching, deposition, sputtering, etc.) being performed in the system.

[0049] In some embodiments, one or more measurement devices (e.g., sensors or measurement devices) may be coupled to the plasma processing chamber 105 to collect real-time data that the control unit 170 can use to control various plasma characteristics (e.g., plasma density, ion flux, ion energy, electron temperature (Te), radical concentration, gas ratios, etc.) by adjusting one or more parameters of the power signal provided by the RF power supply. Examples of adjustable parameters include, for example, the amplitude, frequency, phase, pulse-on time (i.e., pulse width), multi-level pulses, and duration between power levels, and pulse-off time of the source / bias power signal. In some embodiments, the time difference between the source and bias power signals may be another adjustable parameter to control plasma characteristics. For example, the pulse-on time and / or pulse-off time of the source power signal and / or bias power signal may be adjusted relative to one another. In one embodiment, the time difference between the off time of the source power signal and the on time of the bias power signal can be precisely controlled to control bias start-up after the source is shut down or powered down. If the bias does not start up predictably and repeatedly, the ion dose extracted by the bias will vary.

[0050] Various measurement devices may be utilized to collect real-time data from the plasma processing chamber 105 and / or the signal transmission path between the RF power sources 130 / 140 and the plasma processing chamber 105. Examples of measurement devices include, but are not limited to, power sampling sensors, three-point sensors, electromagnetic (EM) sensors, optical sensors, voltage / current sensors (VI sensors), direct current voltage (Vdc) sensors, etc. It will be appreciated that other measurement devices may additionally or alternatively be used to collect real-time data that may be used by the control unit 170 to control various characteristics of the plasma 160.

[0051] In some embodiments, for example, a first VI sensor 180 and a second VI sensor 182 may be coupled to the plasma processing chamber 105 to sense the current (I) and / or voltage (V) of the power signals supplied to the upper and lower electrodes. In the example plasma processing system 100 shown in FIG. 1 , the first VI sensor 180 is coupled between the first matching network 155 and the upper electrode 120 to sense the current and / or voltage of the source power supplied to the upper electrode 120. The second VI sensor 182 is coupled between the second matching network 157 and the lower electrode 125 to sense the current and / or voltage of the bias power supplied to the lower electrode 125.

[0052] In some embodiments, the first VI sensor 180 and the second VI sensor 182 may each be included in a separate power transmission system and may be used to measure the current and / or voltage of a power signal propagating therethrough. For example, the first VI sensor 180 may be included in a first power supply system coupled between the first matching network 155 and the plasma processing chamber 105. The first VI sensor 180 may be used to measure the current and / or voltage of a power signal (e.g., source power) propagating through the first power supply system. In some embodiments, the first VI sensor 180 may include multiple VI sensors within the same power transmission system. Similarly, the second VI sensor 182 may be included in a second power supply system coupled between the second matching network 157 and the plasma processing chamber 105. The second VI sensor 182 may be used to measure the current and / or voltage of a power signal (e.g., bias power) propagating through the second power supply system. Examples of several embodiments of VI sensors are described in U.S. Patent Application No. 16 / 913,526, filed June 26, 2020, entitled "RF Voltage and Current (VI) Sensors and Measurement Methods," and U.S. Patent Application No. 16 / 913,545, filed June 26, 2020, entitled "RF Voltage and Current (VI) Sensors and Measurement Methods," each of which is expressly incorporated herein in its entirety.

[0053] In some embodiments, a single VI sensor can be used to measure pulses in the plasma from a train of multiple plasma pulses delivered to the plasma processing chamber 105. For example, the second VI sensor 182 can be used to measure the voltage generated on the substrate from the source power and bias power, allowing the second VI sensor 182 to measure both pulses generated from the source and bias generators using one sensor. In some embodiments, when multiple frequencies are used to generate the source and / or bias voltages, the bias voltages from the first, second, and third harmonics may be different from the first harmonic of the source voltage. In such embodiments, a single VI sensor can be used to measure the timing of a basic dual-pulse source / bias or triple-pulse shape, such as that shown in FIG. 5.

[0054] In some embodiments, the VI analyzer 190 can receive the raw waveforms output from the first VI sensor 180 and the second VI sensor 182. The VI analyzer 190 can be a signal processor (e.g., a digital signal processor) programmed to extract various RF signal characteristics from the raw waveforms output from the VI sensors. Examples of RF signal characteristics that can be extracted by the VI analyzer 190 include voltage magnitude (|V|), current magnitude (|I|), the phase angle between V and I (Φ), and peak RF power (|V||I|cosΦ). These RF signal characteristics can indicate various plasma impedance and plasma characteristics, such as free electron and ion densities, and ion / radical flux and energy. In some embodiments, the VI analyzer 190 can perform harmonic analysis to extract multiple frequency components from the raw waveforms output from the VI sensors. The VI analyzer 190 can provide the RF signal characteristics to the control unit 170 shown in FIG. 1 .

[0055] In some embodiments, a Vdc sensor 184 may be included in plasma processing chamber 105 to provide a direct current (Vdc) voltage measurement of plasma 160 generated therein. Vdc sensor 184 may be coupled to the plasma processing system focus ring (not shown), chuck 115, or substrate 110. It will be appreciated that a Vdc sensor may also be located in other areas of plasma processing chamber 105. The Vdc measurement signal obtained by Vdc sensor 184 may be provided to control unit 170 for process control. Example embodiments of Vdc sensors are described in U.S. Patent Application Publication No. 2021 / 0013005, the entire contents of which are expressly incorporated herein by reference.

[0056] In some embodiments, an optical sensor 186 (e.g., an optical photodiode) may be included within the plasma processing chamber 105 to detect the intensity of the plasma 160 generated within the plasma processing chamber. In some embodiments, the optical sensor 186 may be coupled to a dielectric (e.g., dielectric 318 in FIG. 3A ) that is coupled to the plasma processing chamber 105 and utilized to provide a uniform distribution of electromagnetic radiation within the plasma processing chamber 105. In other embodiments, the optical sensor 186 may be coupled directly to the plasma processing chamber 105 or may be coupled within the plasma processing chamber 105 to measure the optical intensity of the plasma 160 generated within the plasma processing chamber 105.

[0057] In an alternative embodiment, an optical sensor can be used to measure the optical emission spectrum of the plasma 160, for example, by measuring radical concentration using specific emission lines and combinations of emission lines and ratios. This can be accomplished by the use of optical filters or other commonly known methods. Using an optical sensor to measure the emission spectrum of the plasma 160 can provide a real-time optical plasma response that can be compared to an electrical pulse power input signal (e.g., the power, voltage, or current of a source or bias power signal). The optical signal provided by the optical sensor allows another measurement of the time relationship that can be controlled to provide an optimal plasma to the substrate surface.

[0058] In some embodiments, a pressure controller and measurement system 188 can be coupled to the plasma processing chamber 105 to measure and control the chamber pressure within the plasma processing chamber. In some embodiments, the pressure measurements can be provided to the control unit 170 and used as part of controlling the pulsed plasma process. For example, during pulsed plasma processing, pulse parameters (e.g., pulse on time or pulse magnitude) and / or chamber pressure can be adjusted, thereby controlling the plasma measurements.

[0059] 2A and 2B illustrate various embodiments of a system 200 that can be used to control plasma processing performance of a plasma processing system. In one embodiment, the system 200 illustrated in FIG. 2A or 2B may be integrated with the plasma processing system 100 illustrated in FIG. 1. For example, the system 200 generally includes one or more power sources (e.g., a first power source 202 and / or a second power source 204) coupled to provide a first power signal and a second power signal to the plasma processing chamber 105 to generate a plasma 160 within the plasma processing chamber; one or more measurement devices 206 coupled to collect real-time data corresponding to the first power signal, the second power signal, or the plasma 160; and a power source controller 208 coupled to utilize the real-time data collected by the measurement devices 206 to control various characteristics of the plasma 160 generated within the plasma processing chamber 105. Alternatively, aspects of the system 200 may be implemented as separate, add-on, or additional features of the system 100. For example, the measurement device may also be coupled to the plasma processing chamber to obtain data regarding plasma conditions, such data also controlling pulse timing parameters.

[0060] In some embodiments, multiple power sources can be used to generate and provide the first and second power signals to the plasma processing chamber 105. For example, as shown in FIG. 2A, a first power source 202 can be coupled to provide the first power signal, and a second power source 204 can be coupled to provide the second power signal to the plasma processing chamber 105. In other embodiments, the first and second power signals can be generated and provided by a single power source. For example, as shown in FIG. 2B, the first power source 202 can be coupled to provide the first and second power signals to the plasma processing chamber 105. In the embodiment shown in FIG. 2B, the first power source 202 can provide the first and second power signals to a single electrode to power the plasma processing chamber.

[0061] The first power source 202 and the second power source 204 may be RF and / or DC power sources or generators and / or DC power sources. More specifically, the first power source 202 and the second power source 204 may each be configured to generate a power signal with a set of parameters (e.g., amplitude, frequency, phase, pulse-on time or pulse width, pulse-off time, etc.) that can be varied depending on system requirements and plasma performance. In one embodiment, the first power source 202 may provide a source power with a first set of parameters, and the second power source 204 may provide a bias power with a second set of parameters to the plasma processing chamber 105. As described in more detail below, one or more timing parameters of the source power (e.g., pulse-on time and / or pulse-off time) may be adjusted to control the plasma density of the plasma 160 generated in the plasma processing chamber 105. Similarly, one or more timing parameters of the bias power (e.g., pulse-on time and / or pulse-off time) may be adjusted to control the ion flux / energy of the generated plasma.

[0062] One or more measurement devices 206 may be coupled and configured to generate measurement data that is in-situ and / or out-of-situ for the plasma chamber. In one example, one or more measurement devices 206 may be configured to generate the out-of-situ measurement data by measuring one or more characteristics of the power supplied to the plasma processing chamber 105. In another example, one or more measurement devices 206 may be configured to generate the in-situ measurement data by measuring the response of the plasma 160 generated in the plasma processing chamber 105 to a power signal, chamber pressure, and / or gases supplied to the processing chamber. Examples of measurement devices 206 are shown in FIGS. 1 and 3 and are discussed further herein. The measurement data collected by the measurement devices 206 is provided to the power supply controller 208.

[0063] The power supply controller 208 is coupled to receive the measurement data collected by the measurement device 206 and is configured to control one or more parameters of the first power supply 202, one or more parameters of the second power supply 204, or the chamber pressure in response to the measurement data. In some embodiments, the measurement data may be collected by the measurement device 206 in real time during the plasma process and provided to the power supply controller 208. Using the real-time data, the power supply controller 208 may be configured to adjust the parameters of the first power supply, the parameters of the second power supply, and / or the chamber pressure in real time to control the performance of the plasma process. In one embodiment, the power supply controller 208 may be implemented in the control unit 170 shown in FIG. 1 .

[0064] In one embodiment, the first power supply 202 may provide a source power according to a first set of parameters and the second power supply 204 may provide a bias power according to a second set of parameters to the plasma processing chamber 105 to generate the plasma 160, which may be used to perform a plasma process (e.g., plasma deposition, etching, sputtering, etc.) on the substrate 110. The measurement device 206 may be configured to measure one or more characteristics of the source power, one or more characteristics of the bias power, and / or a response of the plasma 160 generated in the plasma processing chamber 105 to the source / bias power in real time during the plasma process. For example, the measurement device 206 may be configured to measure one or more of the power (P) (e.g., forward power, reflected power, standing wave power, total power, etc.) of an RF power signal transmitted between the RF power source and the plasma processing chamber 105, the voltage (V), current (I) and / or phase (Φ) of the RF power signal supplied to the plasma processing chamber 105 to generate the power plasma 160, the intensity or emission spectrum of the plasma 160 generated in the plasma processing chamber 105, and the DC voltage (Vdc) level of the plasma 160 generated in the plasma processing chamber 105. In some embodiments, the measurement device may additionally be configured to measure the chamber pressure in the plasma processing chamber 105.

[0065] In one embodiment, the power supply controller 208 can use the measurement data provided by the measurement device 206 to adjust a first set of parameters utilized by the first power supply 202, a second set of parameters utilized by the second power supply 204, and / or the chamber pressure to control various characteristics of the plasma 160 generated in the plasma processing chamber 105 during plasma processing. For example, the power supply controller 208 can adjust the amplitude, frequency, phase, pulse-on time (i.e., pulse width), and / or pulse-off time of the source power supplied by the first power supply 202 to control the plasma density of the plasma 160 generated in the plasma processing chamber 105.

[0066] Additionally or alternatively, the power supply controller 208 can adjust the amplitude, frequency, phase, pulse-on time (i.e., pulse width), and / or pulse-off time of the bias power supplied by the second power supply 204 to control the ion flux / energy of the plasma 160 generated in the plasma processing chamber 105. In some embodiments, the power supply controller 208 can maintain the bias power at a low power to further control or increase the plasma density. By maintaining the bias power at a low power, the plasma generated in the plasma processing chamber 105 can be more stable in both (a) allowing particles to suspend above the substrate after a higher power pulse of bias performing etching, and (b) generating by-products and allowing time for the by-products to be pumped out of the plasma processing chamber without the plasma sheath completely collapsing.

[0067] The chamber pressure affects the pulse magnitude, slope, and duration (or pulse width) of the measurement data provided by the measurement device 206. In some embodiments, the power supply controller 208 can adjust the chamber pressure in the plasma processing chamber 105 during plasma processing to control various characteristics of the source power, bias power, and / or plasma response to the source / bias power. For example, the power supply controller 208 can increase the chamber pressure during plasma processing to decrease the amount of measured reflected power from the second power supply 204 (e.g., bias power supply) while increasing the pulse width and decreasing the pulse amplitude of the current signal provided by the second power supply 204. Increasing the chamber pressure can also increase the pulse width and amplitude of the optical intensity of the plasma 160 generated in the plasma processing chamber 105. Other characteristics of the plasma response to the source power, bias power, and / or plasma / bias power can also be changed by adjusting the chamber pressure.

[0068] In some embodiments, the first power supply 202 and the second power supply 204 may be connected to the same plasma generating device (e.g., source or bias), and the power signals provided by the first and second power supplies may be superimposed. In such embodiments, the power supply controller 208 may control the first power supply 202 to provide continuous or pulsed power to the plasma processing chamber 105, and may adjust the power or time of the second power supply 204 to maintain a constant on-time by adjusting the power of the first power supply 202 to maintain a constant on-time, such as by adjusting the power of the first power supply 202 to maintain a minimum value, to maintain optimal plasma characteristics for the application of pulses by the first power supply 202.

[0069] FIG. 3A illustrates another embodiment of a system 300 for controlling plasma processing performance of a plasma processing system. In the embodiment illustrated in FIG. 3A, the system 300 includes a power supply 302 that generates a power signal, various system elements that deliver the power signal generated by the power supply 302 to the plasma processing chamber 105, and a number of measurement devices that measure one or more aspects of the power signal provided to the plasma processing chamber 105 and / or the response of the plasma 160 generated within the plasma processing chamber 105 to the power signal provided to the plasma processing chamber 105. In the embodiment illustrated in FIG. 3A, the system elements used to deliver the power signal to the plasma processing chamber 105 include a mixer 304, a power amplifier 306, a coaxial cable (coax)-to-waveguide projection 308, a power transfer coupling 310, a mechanical tuning device 312, a power combiner 314, a power projection 316, and a dielectric 318. However, it will be recognized that additional or alternative elements for delivering RF and / or DC power signals to the plasma processing chamber 105 may be used.

[0070] In some embodiments, the RF power source 302 shown in Figure 3A may have a single output that generates one power signal. For example, the power source 302 shown in Figure 3A may be the first power source 202 or the second power source 204 described above with reference to Figures 2A or 2B. In such embodiments, the system 300 may include a set of system elements and measurement devices for the first power source 202 and the second power source 204.

[0071] 3A may include a multiple-output RF or DC power supply capable of utilizing a first set of parameters to generate a first power signal at a first power output and a second set of parameters to generate a second power signal at a second power output. In such an embodiment, a mixer 304 may be included to switch between the first and second power signals generated by the multiple-output power supply.

[0072] 3A , the power signal generated by the power supply 302 is provided to a power amplifier 306 for amplification. For example, the power amplifier 306 can amplify the (RF and / or DC) power signal generated by the power supply 302 to a level suitable for maintaining a plasma field in the plasma processing chamber 105. In some embodiments, a power sampling sensor 322 can sample the power signal output from the power amplifier 306. For example, the power sampling sensor 322 can measure the forward power and / or reflected power of the power signal output from the power amplifier 306. The power sampling sensor 322 is an example of an off-site plasma chamber measurement device that may be included in the system 300 to obtain off-site measurement data (e.g., forward power and / or reflected power) obtained from the power signal output from the power amplifier 306.

[0073] The output of the power amplifier 306 is coupled to a coax-to-waveguide projection 308, which is coupled to a power transfer coupling 310. The power transfer coupling 310 may generally include a waveguide. In some embodiments, a multi-point sensor, such as a three-point sensor 324, may be used to measure a standing wave formed in the waveguide. For example, the three-point sensor 324 may measure the power in the waveguide at three points in the standing wave, each point separated by a known distance. In certain embodiments, the known distance may be one-eighth of the wavelength of the standing wave formed in the waveguide. The three-point sensor 324 is another example of an off-site measurement device that may be included in the system 300 to obtain off-site measurement data (e.g., multiple power measurements) from an RF power signal propagating in a waveguide.

[0074] In some embodiments, the power transfer coupling 310 may be coupled to a mechanical tuning device 312. The inclusion of the mechanical tuning device 312 may provide adjustable mechanical tuning to the power signal provided to the plasma processing chamber 105. For example, the mechanical tuning device 312 may provide mechanical adjustment to one or more electrical characteristics of the power signal. The mechanical tuning device 312 may be implemented as an adjustable waveguide stub, an adjustable slit, an adjustable aperture, or the like. In one embodiment, the mechanical tuning device 312 may include a single tuning element. Alternatively, the mechanical tuning device 312 may include multiple tuning elements.

[0075] The power transfer coupling 310 (or mechanical tuning device 312) is coupled to the power combiner 314. In some embodiments, an electromagnetic (EM) sensor 326 may be coupled to measure electromagnetic energy within the power combiner 314. In one embodiment, the EM sensor 326 may include an electric field (E-field) pickup element. In such an embodiment, the EM sensor 326 may be used to measure the total power of the power signal at the power combiner 314. The EM sensor 326 is yet another example of an ex-situ plasma chamber measurement device that may be included in the system 300 to obtain ex-situ measurement data (e.g., total power) of the power signal at the power combiner 314.

[0076] In some embodiments, a power projection portion 316 (e.g., a slit or aperture) can connect the power coupler 314 to a dielectric 318 coupled to the plasma processing chamber 105. Energy emitted through the power projection portion 316 can be distributed throughout the dielectric 318 to uniformly distribute electromagnetic radiation within the plasma processing chamber 105. In some embodiments, an optical sensor 328, such as a photodiode sensor, can be coupled to the dielectric 318 to detect the optical intensity of the plasma 160 generated within the plasma processing chamber 105. In other embodiments, the optical sensor 328 can be directly coupled to the plasma processing chamber 105, as described above with reference to FIG. 1 . In either case, the optical sensor 328 can be included in the system 300 to obtain measurement data, such as the optical intensity of the plasma 160 generated within the plasma processing chamber 105, either within the plasma chamber or external to the plasma chamber.

[0077] In some embodiments, the power combiner 314, power projection portion 316, and dielectric 318 element may be implemented in a power transmission system 320 coupled and configured to deliver a power signal to the plasma processing chamber 105. The current (I) and voltage (V) waveforms transmitted through the power transmission system 320 may be functions of position (x) and time (t), i.e., I(x,t) and V(x,t), each containing multiple frequency components. When a single frequency component f is present, the current (I) and voltage (V) are expressed as Re(I(x)e jωt ) and Re(V(x)e j(ωt+Φ) ) and can be described by a sinusoidal waveform written succinctly as ω=2πf, j 2= -1, and Re is the real part of the complex function. The current (I) and voltage (V) waveforms each have a magnitude (|V| and |I|), and each waveform is separated from the other by a phase angle Φ. Examples of power transfer systems 320 that may be used in connection with the present embodiments are described in U.S. patent application Ser. No. 16 / 913,526, filed June 26, 2020, entitled "RF Voltage and Current (VI) Sensors and Measurement Methods," and U.S. patent application Ser. No. 16 / 913,545, filed June 26, 2020, entitled "RF Voltage and Current (VI) Sensors and Measurement Methods," each of which is expressly incorporated herein in its entirety.

[0078] In some embodiments, one or more VI sensors 330 may be coupled to the power transmission system 320 shown in FIG. 3A to sense the current and voltage of the power signal supplied to the plasma processing chamber 105. The one or more VI sensors 330 are additional examples of off-device measurement devices that may be included in the system 300 to obtain off-device measurement data (e.g., voltage, current, and / or phase) from the power signal supplied to the plasma processing chamber 105. The one or more VI sensors 330 may generally be configured as described in the above-mentioned incorporated references. For example, the one or more VI sensors 330 may use geometric symmetry and differential measurement techniques to provide V and I at the sensor location x with high accuracy. In some embodiments, multiple VI sensors 330 may be used at various locations along the power transmission system 320 to probe signals at those locations. Because V and I are functions of location x, each VI sensor may be positioned as close as possible to its desired measurement location. For example, if it is desirable to monitor and control the plasma process using accurate measurements of the voltage and current of the power signal supplied to the plasma processing chamber 105, the VI sensor used for this purpose may be located near where the power signal enters the plasma processing chamber 105.

[0079] In some embodiments, a Vdc and / or pressure sensor 332 may be included in the plasma processing chamber 105 to measure the DC voltage (Vdc) of the plasma 160 generated in the plasma processing chamber and / or to measure the chamber pressure within the processing chamber. Accordingly, in some embodiments, the sensor 332 in the block connected to the chamber may include one sensor (either a Vdc sensor or a pressure sensor) or multiple sensors (a Vdc sensor and a pressure sensor). As discussed above, optical sensors may also be connected to the chamber. The Vdc and / or pressure sensor 332 are other examples of in-situ measurement devices that may be included in the system 300 to obtain in-situ measurement data (e.g., Vdc level) of the plasma 160 generated in the plasma processing chamber 105. In some embodiments, the Vdc sensor may be coupled to the plasma processing system focus ring (not shown), the chuck 115, or the substrate 110, as described above with reference to FIG. 1 . It will be appreciated that the Vdc sensor may be located in other areas of the plasma processing chamber 105. An example of a Vdc sensor that may be used in connection with the present embodiment is described in U.S. Patent Application Publication No. 2021 / 0013005, the contents of which are incorporated herein by reference.

[0080] 3A , measurement data from power sampling sensor 322, three-point sensor 324, EM sensor 326, optical sensor 328, VI sensor 330, and Vdc and / or pressure sensor 332 are provided to power supply controller 208. In some embodiments, power supply controller 208 can use measurement data received from one or more of these measurement devices (e.g., one or more of sensors 322, 324, 326, 328, 330, and 332) to provide an operating signal to power supply 302 to control the power signal supplied to plasma processing chamber 105. Although optical sensor 328 is shown in FIG. 3A as being coupled to power supply dielectric 318, optical sensor 328 may alternatively be implemented using a separate window in plasma chamber 105.

[0081] FIG. 3B is a graph illustrating several examples of measurement data that may be obtained from one or more of the measurement devices shown in FIGS. 1, 2A-2B, and 3A. The graph shown in FIG. 3B plots bias reflected power 340, source voltage 350, power supply current 352, bias voltage 360, bias current 362, and light intensity 370 across the top of the graph, and bias phase 364 and direct current voltage (Vdc) 380 (measured at the substrate) across the bottom of the graph. The signals shown in FIG. 3B were obtained from various measurement devices as described above while providing a 500 W source power signal for 125 microseconds (usec) and a 100 W bias power signal for 100 usec to a plasma processing chamber. As shown in FIG. 3B, bias reflected power 340 increases during startup and stabilizes after startup.

[0082] In an example embodiment, the power supply controller 208 can correlate the voltage (V) and current (I) signals received from the VI sensor 330, the Vdc signal received from the Vdc sensor, the pressure measurements from the pressure sensor, and / or the light intensity signal received from the optical sensor 328 with the plasma density, ion flux, and ion energy. Furthermore, the power supply controller 208 can use the measurement data received from the VI sensor 330, the Vdc sensor, and / or the pressure sensor 332, and / or the optical sensor 328 to better characterize and / or control the plasma process. For example, the power supply controller 208 can use the received measurement data to adjust one or more parameters (e.g., amplitude, frequency, phase, pulse-on time, pulse-off time, etc.) of the source and / or bias power signals supplied to the plasma processing chamber 105 to maintain a desired plasma density and / or a desired ion energy or flux during the plasma process. Additionally or alternatively, the power supply controller 208 can adjust the chamber pressure to maintain a desired plasma density and / or a desired ion energy or flux during the plasma process.

[0083] In some embodiments, the power supply controller 208 can receive voltage (V), current (I), and / or phase (Φ) from the VI sensor 330 and then calculate the plasma density and ion flux at the substrate by converting the V, I, and / or Φ measurements received from the VI sensor 330 to the substrate using an RF impedance model. In other words, the VI sensor 330 obtains actual measurements (V, I, Φ) from the power signal used to provide the virtual measurements at the substrate.

[0084] Those skilled in the art will recognize that one or more additional elements may be added to the system 300 shown in Figure 3A to enhance the operation of the methods and processes described herein. Furthermore, those skilled in the art will recognize that one or more elements of the system of Figure 3A may be omitted, depending on system requirements and hardware availability. The embodiment of Figure 3A is merely illustrative of options that may be used in conjunction with this embodiment, and is not intended to limit the scope of the present invention to any particular embodiment.

[0085] FIG. 4 is a block diagram illustrating a control loop 400 that may be used in the system 200 shown in FIGS. 2A-2B and / or the system 300 shown in FIG. 3A to control plasma processing performance. In some embodiments, the control loop 400 shown in FIG. 4 may be implemented as an iterative loop that receives as input a specified power recipe (r) 402 having preset values. In one example of the control loop 400 shown in FIG. 4, the power amplifier 306 shown in FIG. 3A provides a power signal (e.g., a source power signal and / or a bias power signal) to the plasma processing chamber 105 to generate the plasma 160, which is monitored by the measurement device 206. The power signal may be a pulsed DC signal and / or an RF signal having an amplitude, frequency, phase, pulse-on time (i.e., pulse width), and pulse-off time. The specified power recipe (r) 402 may also include the pulse timing of the power source. When multiple frequencies and amplitudes are used with one power source, the recipe 402 has time-dependent parameters with adjustable limits, such as automatically adjustable power ranges along with timing relationships between pulse durations and phases in a pulse sequence, as shown, for example, in FIG.

[0086] One or more measurement devices 206 can be used to measure one or more characteristics of the power signal supplied to the plasma processing chamber 105, the plasma response to a predetermined power characteristic, and / or the chamber pressure. As described above, the one or more measurement devices 206 can include on-site and / or off-site measurement devices. In response to measurement data received from the measurement devices 206, the power supply controller 208 can adjust one or more control knobs or control settings of the control loop 400 (e.g., control blocks 404, 406, 408, 410, and 412) to achieve desired plasma performance. Pulse sequence changes can be updated simultaneously or separately. For example, control blocks 404 and 410 are fast control loops that adjust impedance matching and interact with control block 408 if impedance matching adjustment is necessary. In some embodiments, pulse timing settings can be adjusted by control block 406 in a feedforward update to compensate for non-optimal pulse characteristics and extend pulse duration. In some embodiments, the pulse timing settings can also be adjusted with feedback updates (not shown in FIG. 4) in control block 406 to change the timing relationships between multiple pulses and between multiple power supplies, for example, between the source power supply and the bias power supply.

[0087] In one embodiment, the power supply controller 208 may begin by adjusting electronic tuning settings in control block 404. The electronic tuning control settings may be updated to align with the plasma power control plan defined by the power recipe (r). The power supply controller 208 may then adjust one or more timing settings in control block 406. In some embodiments, the power supply controller 208 may adjust the pulse-on time (i.e., pulse width) of source power pulses supplied to the plasma processing chamber 105 to control the plasma density of the plasma 160 generated in the plasma processing chamber. Additionally or alternatively, the power supply controller 208 may adjust the pulse-on time and / or pulse-off time of bias power pulses supplied to the plasma processing chamber 105 to control the ion flux / energy of the plasma 160 generated in the plasma processing chamber. After the timing settings are adjusted, the electronic tuning settings may again be updated in control block 404.

[0088] The power supply controller 208 can then adjust the power amplitude setting in control block 408. In some embodiments, the power amplitude setting may be iteratively updated until a threshold plasma measurement is met. Once the power amplitude level is adjusted in control block 408, the power supply controller 208 can readjust the electronic adjustment setting in control block 404 and the timing setting in control block 406. A second adjustment can then be made to the power amplitude setting in control block 408.

[0089] The power supply controller 208 can then adjust the frequency tuning setting in control block 410. In some embodiments, the frequency tuning setting may be updated to adjust the frequency of the RF power signal supplied to the plasma processing chamber 105. Once the frequency tuning setting is adjusted, the power supply controller 208 can readjust the electronic tuning setting in control block 404, the timing setting in control block 406, and the power amplitude setting in control block 408, as described above.

[0090] The power supply controller 208 may then adjust the mechanical tuning (e.g., pressure control actuator or matcher control actuator) setting in control block 412. In some embodiments, the mechanical tuning setting adjusted in control block 412 may be a pressure control setting used to adjust the chamber pressure in the plasma processing chamber. In other embodiments, the mechanical tuning setting may be used to adjust the impedance matching. Once the mechanical tuning setting is adjusted, the process may be repeated to readjust the electronic tuning setting in control block 404, the timing setting in control block 406, the power amplitude setting in control block 408, and the frequency tuning setting in control block 410.

[0091] 2-4 illustrate various embodiments of control systems and control loops that may be used to control plasma processing. In some embodiments, the techniques described herein can be used to characterize and control plasma processing during real-time substrate processing. The techniques described herein may also be used to initially or periodically characterize a plasma processing system to maintain process control during use of the plasma processing system. The techniques described herein may generally be used to control various plasma characteristics, including, but not limited to, plasma density and ion flux / energy.

[0092] In preferred embodiments of the present disclosure, measurement data obtained from one or more measurement devices can be used to adjust one or more timing parameters of a power signal supplied to a plasma processing chamber to maintain a desired plasma density and / or a desired ion flux / energy during plasma processing. In particular, measurement data obtained from one or more measurement devices can be used to provide feedforward or feedback control of one or more timing parameters of a power signal during plasma processing to better control the plasma processing and improve performance of the plasma processing.

[0093] FIG. 5 illustrates various timing parameters of power signals that may be supplied to the plasma processing chamber during plasma processing. In particular, FIG. 5 illustrates the source voltages (V source ) and bias voltage (V1 bias , V2 bias 5 shows an example pulse template for a source and bias voltage pulse. The pulse template shown in FIG. 5 shows various timing parameters for the source and bias voltage pulses. Initial values ​​for these timing parameters may be specified in the power recipe as power recipe settings and may be adjusted during pulsed plasma processing to control various characteristics of the plasma, such as plasma density and ion flux / energy. In some embodiments, V source and V bias The measurements of V may be obtained from two separate measurement devices at two different locations, such as the VI sensors 180, 182 shown in FIG. source and V bias Measurements of V may be obtained from a single measurement device positioned to sense power signals from multiple power sources related to measurements of interest for the plasma substrate. For example, V sensor 182 shown in FIG. 1 may be used to measure V shown in FIG. source and V bias Measurements of can be obtained.

[0094] While source and bias voltages are shown in the example pulse template shown in Figure 5, it will be appreciated that other parameters of the source and bias power signals may also be used to control the plasma characteristics. For example, the current (I) or power (P) measured from the source and bias power supplies, the Vdc level measured from the plasma processing chamber, and / or the optical intensity or emission spectrum of the plasma may also be used to characterize and control pulsed plasma processing in accordance with the techniques described herein.

[0095] During the first phase (P1) of the pulsed plasma treatment, the source voltage (V source ) pulses are delivered to a plasma processing chamber to generate a plasma. sourceThe pulses have a desired amplitude and a desired pulse width as specified in the power recipe. For example, the power recipe may have a desired amplitude during execution of a minimum voltage peak (Peak Min) and a maximum voltage peak (Peak Max), and a minimum on-time (t min-on ) and maximum on-time (t max-on ) to have the desired pulse width during the execution of V source You can specify a pulse. source Both the amplitude and pulse width of the pulse may be selected and / or adjusted to control the plasma density of the generated plasma.

[0096] For example, V source The area under the curve of the pulse can be a measured and calculated value that represents the change in plasma density over time. source If the minimum is not met during the duration of the pulse, the power supply controller extends the on-time of the pulse by t delay-max Extend to t min-on The power or other control parameters can be adjusted to maintain the specification. These updates can be averaged over a number of pulses, and the source voltage control parameters can then be updated to maintain the desired pulse profile without continually extending the pulse duration. While control of plasma density in one embodiment is described herein, it will be appreciated that other characteristics of the plasma process can be similarly controlled using the techniques described herein. Other characteristics include, but are not limited to, the plasma's electron temperature, ion flux, and / or ion energy.

[0097] During subsequent phases of the pulsed plasma process, the source voltage is turned off and a bias voltage is supplied to the plasma processing chamber to control the ion flux / energy of the generated plasma. In the example pulse template shown in FIG. 5, during the second phase (P2) of the pulsed plasma process, the first bias voltage (V1 bias ) pulse is supplied to the plasma processing chamber, and a second bias voltage (V2 bias) pulses are delivered to the plasma processing chamber. source Like the pulses, the bias voltage pulses may each have a desired amplitude and a desired pulse width as specified in a power recipe. For example, the power recipe may specify V1 to achieve a plasma that polymerizes the sidewalls of the profile. bias The pulse has the desired amplitude during which the minimum voltage peak (Peak1 Min) and maximum voltage peak (Peak1 Max) occur, and the minimum on-time (t 1min-on ) and maximum on-time (t 1max-on ) can be specified to have pulses of desired pulse widths during the execution of the power recipe. The power recipe can further be configured to control the ion flux / energy in the plasma that etches the bottom of the feature, by adjusting V2 bias The pulse has the desired amplitude during which the minimum voltage peak (Peak2 Min) and maximum voltage peak (Peak2 Max) occur, and the minimum on-time (t 2min-on ) and maximum on-time (t 2max-on ) can be specified to have a desired pulse width during the execution of the pulsed plasma process. The area under the bias voltage curve reflects the total ion dose. During the fourth phase (P4) of the pulsed plasma process, the source and bias voltages are turned off until the next cycle of the pulsed plasma process.

[0098] FIG. 6 is a graph illustrating various control methods that may be used to adjust one or more timing parameters of a power signal supplied to a plasma processing chamber. In particular, the graphs illustrated in FIG. 6 provide various feedforward and feedback control methods that may be used to adjust timing parameters of a power signal supplied to a plasma processing chamber to control the plasma density and / or ion flux / energy of the plasma generated in the plasma processing chamber. The feedforward and feedback control methods illustrated in FIG. 6 can be used to control plasma performance in real time during plasma processing in the plasma processing chamber. The control method illustrated in FIG. 6 can generally be implemented by a controller, such as, for example, the control unit 170 of FIG. 1 or the power supply controller 208 of FIGS. 2-4.

[0099] The graph shown in Figure 6 shows the source voltage (V source ) pulse and bias voltage (V bias ) pulse. Vr is V source and V bias The threshold voltage of the rising edge of the pulse, V f are the threshold voltages of the falling edges of these pulses. The pulse parameters V1, V2, V3, and V4 are r In some embodiments, the Vs shown in FIG. ource and V bias The pulses can be monitored by a measurement device coupled to the plasma processing chamber. Examples of measurement devices are discussed above with reference to Figures 1-4. While source and bias voltages are shown in Figure 6, the control methods described herein can additionally or alternatively utilize other parameters of the RF power signal (e.g., current, power, Vdc, light intensity, etc.) to control plasma characteristics.

[0100] In some embodiments, a feedforward control method is used to adjust the source voltage (V) supplied to the plasma processing chamber during the first phase (P1) of the pulsed plasma process to maintain a desired plasma density during the pulsed plasma process. source ) timing parameters can be adjusted. For example, as shown in Figure 6, the power recipe allows for adjusting the V (shown by the solid line) source The pulse is ideally measured at time t1, the rising edge threshold voltage (V r ) and the falling edge threshold voltage (V f ) should occur between V source The pulse is t on However, in practice, the V (shown as a dashed line) supplied to the plasma processing chamber may be specified to have a specified pulse-on time (or pulse width) corresponding to V = t - t. source The pulse continues until time t2, when the rising edge threshold voltage (V r1) may not be satisfied. In this case, the feedforward control method shown in FIG. 6 extends time t3 to time t4 to maintain the specified plasma density. source Pulse on time (i.e., wider V source pulse width).

[0101] A feedforward control method used during the first phase (P1) of the pulsed plasma process can be used to adjust the pulse on time (or pulse width) of the source voltage in real time during each cycle of the pulsed plasma process based on measurement data generated by a measurement device and received by the controller during that cycle. In one embodiment, the measurement device measures V during each cycle of the pulsed plasma process. source The rising edge of a pulse (e.g., V r or V r1 ) can be detected. Based on the rising edge detected by the measurement device, the controller adjusts V to maintain a predetermined plasma density. source V during the corresponding cycle of pulsed plasma treatment to control the pulse-on time (or pulse width) of the pulse. source The falling edge of the pulse (V f ) can be adjusted. For example, V source The rising edge of a pulse (e.g., V r1 ) is not detected until time t2, the controller source The falling edge of the pulse (V f ) to time t4 and V source Extend the pulse on time to achieve the desired V source The pulse width can be maintained.

[0102] In some embodiments, a bias voltage (V) supplied to the plasma processing chamber during the second (P2) and third (P3) phases of the pulsed plasma process is controlled using another feedforward control method to maintain a desired ion flux / energy during the pulsed plasma process. bias) can be adjusted. For example, as shown in FIG. 6, the timing parameters of V bias The pulse reaches the first rising edge threshold voltage (V r1 ), at time t4, the second rising edge threshold voltage (V r2 ) and at time t6, the falling edge threshold voltage (V f ) in the feedforward control method shown in FIG. 6. In this case, the time t5 is extended to the time t6, and a longer V bias On-time (i.e., longer V bias A specified ion flux / energy can be maintained by providing a pulse width.

[0103] A feedforward control method used in the second phase (P2) and third phase (P3) of the pulsed plasma process can be used to adjust the pulse on time (or pulse width) of the bias voltage in real time during each cycle of the pulsed plasma process based on measurement data generated by a measurement device and received by the controller during that cycle. In one example embodiment, the measurement device adjusts the pulse on time (or pulse width) of the bias voltage in real time during each cycle of the pulsed plasma process based on measurement data generated by a measurement device and received by the controller during that cycle. bias The rising edge of a pulse (e.g., V r1 or V r2 ) can be detected. Based on the rising edge detected by the measurement device, the controller adjusts V to maintain the specified ion flux / energy. bias V during the corresponding cycle of pulsed plasma treatment to control the pulse-on time (or pulse width) of the pulse. bias The falling edge of the pulse (V f ) can be adjusted. For example, V bias The rising edge of a pulse (e.g., V r2 ) is not detected until time t4, the controller bias The falling edge of the pulse (V f ) to time t6 and V bias Extend the on-time of the pulse to achieve the desired V bias The pulse width can be maintained.

[0104] In some embodiments, the feedback control method comprises: bias Adjusting the pulse-off time may be used during the fourth phase (P4) of the pulsed plasma process to control the bias / power pulse interaction. For example, as shown in Figure 6, the power recipe may initially specify that the source and bias voltages be turned off from time t5 to time t7 until the next cycle of the pulsed plasma process begins at time t1. However, if the V bias When adjusting the pulse on-time, the feedback control method shown in FIG. 6 adjusts V in the next cycle of the pulsed plasma process based on the adjustment made during the current cycle. bias The on-time and off-time of the pulse can be adjusted automatically. For example, V bias If the pulse on time is extended in the current cycle of the pulsed plasma treatment, the feedback control method is to bias In the next cycle of pulsed plasma treatment, V is adjusted to control the pulse width (or bias power). bias The pulse-on time of the pulse can be automatically extended and the pulse-off time can be shortened.

[0105] An exemplary method of controlling plasma performance in accordance with the techniques described herein is illustrated in Figure 7. It will be appreciated that the embodiment illustrated in Figure 7 is exemplary only, and that additional methods may utilize the techniques described herein. Furthermore, the steps described are not intended to be exclusive, and additional steps may be added to the method illustrated in Figure 7. Furthermore, the order of the steps is not limited to the order illustrated, as different orders may occur and / or various steps may be combined or performed simultaneously.

[0106] FIG. 7 is a flow diagram illustrating one embodiment of a method 700 for controlling plasma processing performance in a system for processing a substrate, the system including one or more power supplies. The method 700 illustrated in FIG. 7 may be generally performed in a plasma processing system. While not limited to such an embodiment, FIG. 1 illustrates one embodiment of a plasma processing system 100 that may utilize the method 700. Various steps of the method 700 illustrated in FIG. 7 may be performed by a controller coupled to or included within the plasma processing system. In some embodiments, these steps may be performed using, for example, the control unit 170 illustrated in FIG. 1 and / or the power supply controller 208 illustrated in FIGS. 2-4.

[0107] Generally, method 700 may include providing a first power signal from one or more power sources to a plasma processing chamber (step 710) to generate a plasma in the plasma processing chamber for processing a substrate by pulsed plasma processing. The first power signal may generally include a first set of timing parameters specifying a pulse-on time and a pulse-off time of the first power signal. Method 700 may further include providing a second power signal from one or more power sources to the plasma processing chamber (step 720). The second power signal may generally include a second set of timing parameters specifying a pulse-on time and a pulse-off time of the second power signal. The first power signal and the second power signal may be obtained from a single power source or from multiple power sources.

[0108] Method 700 may further include generating measurement data corresponding to the first power signal, the second power signal, the plasma, and / or the chamber pressure (step 730). The measurement data may be generated in real time during the pulsed plasma process. Method 700 may further include adjusting one or more timing parameters of the first power signal, one or more timing parameters of the second power signal, and / or the chamber pressure in response to the measurement data to modify the pulse width of the first power signal and / or the pulse width of the second power signal to control one or more characteristics of the plasma during the plasma process (step 740). The one or more characteristics of the plasma may include, but are not limited to, the plasma density, ion flux, and / or ion energy of the plasma.

[0109] In some embodiments, the first power signal may be a source power signal. In such embodiments, method 700 may adjust one or more timing parameters of the first power signal by adjusting a pulse-on time of the first power signal to control the plasma density of the plasma (step 740). More specifically, method 700 may adjust one or more timing parameters of the first power signal by adjusting a pulse-on time of the first power signal in real time during each cycle of the pulsed plasma process based on measurement data generated during that cycle (step 740). For example, method 700 may generate measurement data by detecting a rising edge of the first power signal during each cycle of the pulsed plasma process (step 730), and adjust one or more timing parameters of the first power signal by adjusting a falling edge of the first power signal during each cycle of the pulsed plasma process to control the pulse-on time of the first power signal to maintain a specified plasma density (step 740).

[0110] In other embodiments, the second power signal may be a bias power signal. In such embodiments, method 700 may adjust one or more timing parameters of the second power signal by adjusting a pulse-on time of the second power signal to control the ion flux and / or ion energy of the plasma (step 740). More specifically, method 700 may adjust one or more timing parameters of the second power signal by adjusting a pulse-on time of the second power signal in real time during each cycle of the pulsed plasma process based on measurement data generated during that cycle (step 740). For example, method 700 may generate measurement data by detecting a rising edge of the second power signal during each cycle of the pulsed plasma process (step 730), and adjust one or more timing parameters of the second power signal by adjusting a falling edge of the second power signal during each cycle of the pulsed plasma process to control the pulse-on time of the second power signal to maintain a specified ion flux and / or ion energy (step 740).

[0111] In some embodiments, method 700 can adjust one or more timing parameters of the second power signal in a next cycle of the pulsed plasma process if the pulse-on time of the second power signal is adjusted during a current cycle of the pulsed plasma process (step 740). For example, method 700 can adjust the pulse-on time and the pulse-off time of the second power signal in a next cycle of the pulsed plasma process based on the adjustments made during the current cycle.

[0112] It should be noted that references throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of the present invention, but do not necessarily mean that it is present in all embodiments. Thus, the appearances of "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily refer to the same embodiment of the present invention. Furthermore, particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments. In other embodiments, various additional layers and / or structures may be included and / or described features may be omitted.

[0113] As used herein, the term "substrate" refers to and includes a substrate or structure upon which a material is formed. It is understood that a substrate may include a single material, multiple layers of different materials, or one or more layers having regions of different materials or structures therein. These materials may include semiconductors, insulators, conductors, or combinations thereof. For example, a substrate may be a semiconductor substrate, a base semiconductor layer on a supporting structure, a metal electrode, or a semiconductor substrate having one or more layers, structures, or regions formed thereon. The substrate may be a conventional silicon substrate or other bulk substrate including a layer of semiconducting material. As used herein, the term "bulk substrate" refers to and includes not only silicon wafers, but also silicon-on-insulator ("SOI") substrates such as silicon-on-sapphire ("SOS") and silicon-on-glass ("SOG") substrates, epitaxial layers of silicon on a base semiconductor substrate, and other semiconductor or optoelectronic materials such as silicon germanium, germanium, gallium arsenide, gallium nitride, and indium phosphide. The substrate may be doped or undoped.

[0114] Various embodiments describe systems and methods for controlling plasma processing performance of a system for processing a substrate. A substrate may include any material portion or structure of a device, particularly a semiconductor or other electronic device, and may be a base substrate structure, such as a semiconductor substrate, or a layer on or overlying the base substrate structure, such as a thin film. Thus, the term "substrate" is not intended to be limited to any particular base structure, underlying or overlying layer, patterned or unpatterned layer, but rather is intended to include any such layer or base structure, and any combination of layers and / or base structures. In some cases, the term "substrate" may be used to describe a patterned or unpatterned wafer, such as a device wafer or a carrier wafer.

[0115] Those skilled in the relevant art will recognize that various embodiments can be practiced without one or more of the specific details, or with alternative and / or additional methods, materials, or elements. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of various embodiments of the invention. Similarly, for purposes of explanation, specific numbers, materials, and configurations are disclosed to provide a thorough understanding of the invention. Nevertheless, the invention may be practiced without the specific details. Furthermore, it should be understood that the various embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.

[0116] Further modifications and alternative embodiments of the above-described systems and methods will be apparent to those skilled in the art from this specification. Accordingly, it will be appreciated that the above-described systems and methods are not limited to these illustrative configurations. It is understood that the forms of the systems and methods shown and described herein are to be construed as exemplary embodiments. Various modifications may be made in implementation. Thus, while the invention is described herein with reference to specific embodiments, various modifications and changes can be made without departing from the scope of the invention. Accordingly, the specification and drawings should be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the invention. Furthermore, benefits, advantages, or solutions to problems described herein with respect to specific embodiments are not intended to be construed as essential, required, or essential features or elements of the claims.

Claims

1. 1. A method of controlling plasma performance in a system for processing a substrate, the system including one or more power sources, comprising: providing a first power signal from the one or more power sources to the plasma processing chamber to generate a plasma in the plasma processing chamber for processing the substrate by a pulsed plasma process, the first power signal including a first set of timing parameters specifying a pulse-on time and a pulse-off time of the first power signal; providing a second power signal from the one or more power sources to the plasma processing chamber, the second power signal including a second set of timing parameters specifying a pulse-on time and a pulse-off time of the second power signal; generating measurement data corresponding to the first power signal, the second power signal, the plasma and / or chamber pressure, the measurement data being generated in real time during the pulsed plasma process; adjusting, in response to the measurement data, one or more timing parameters of the first power signal, one or more timing parameters of the second power signal, and / or the chamber pressure to modify a pulse width of the first power signal and / or a pulse width of the second power signal to control one or more characteristics of the plasma during the plasma processing; A method comprising:

2. 10. The method of claim 1, wherein providing the first power signal and providing the second power signal comprises providing the first power signal and the second power signal from a single power source.

3. 2. The method of claim 1, wherein providing the first power signal comprises providing the first power signal from a first power source, and providing the second power signal comprises providing the second power signal from a second power source different from the first power source.

4. The method of claim 1 , wherein generating measurement data comprises generating in-device measurement data.

5. generating measurement data the optical intensity or emission spectrum of the plasma generated in the plasma processing chamber; and / or The direct current voltage (Vdc) level of the plasma generated in the plasma processing chamber The method of claim 4, comprising measuring one or more of:

6. The method of claim 1 , wherein generating the measurement data comprises generating off-device measurement data.

7. generating measurement data the power, voltage, current and / or phase of the first power signal; the power, voltage, current and / or phase of the second power signal; and power, voltage, current and / or phase of at least one harmonic of the first power signal and / or the second power signal; The method of claim 6, comprising measuring one or more of:

8. The method of claim 1 , wherein the one or more characteristics of the plasma that are controlled include plasma density, electron temperature, gas dissociation, etch material selectivity, ion flux, and / or ion energy of the plasma.

9. 10. The method of claim 1, wherein the first power signal is a source power signal, and wherein adjusting comprises adjusting the pulse on time of the first power signal to control a plasma density of the plasma.

10. 10. The method of claim 9, wherein the adjusting comprises adjusting the pulse on-time of the first power signal in real time during the cycle of the pulsed plasma treatment based on the measurement data generated during the cycle.

11. 10. The method of claim 9, wherein generating the measurement data includes detecting a rising edge of the first power signal during a cycle of the pulsed plasma treatment, and adjusting includes adjusting a falling edge of the first power signal during the cycle of the pulsed plasma treatment to control the pulse on time of the first power signal to maintain a predetermined plasma density.

12. 10. The method of claim 1, wherein the second power signal is a bias power signal, and wherein adjusting comprises adjusting the pulse on-time of the second power signal to control ion flux and / or ion energy of the plasma.

13. 13. The method of claim 12, wherein the adjusting comprises adjusting a pulse on time of the second power signal in real time during the cycle of the pulsed plasma treatment based on the measurement data generated during the cycle.

14. 13. The method of claim 12, wherein generating measurement data comprises detecting a rising edge of the second power signal during each cycle of the pulsed plasma process, and adjusting comprises adjusting a falling edge of the second power signal during each cycle of the pulsed plasma process to control the pulse on time of the second power signal to maintain a predetermined ion flux and / or ion energy.

15. 13. The method of claim 12, wherein if the pulse-on time of the second power signal is adjusted during a current cycle of the pulsed plasma treatment, adjusting further comprises adjusting the pulse-on time and the pulse-off time of the second power signal in a next cycle of the pulsed plasma treatment based on the adjustment made during the current cycle.

16. The method of claim 1 , wherein the adjusting is performed to control the relative timing of the first power signal and the second power signal.

17. 17. The method of claim 16, wherein the adjusting is performed to control a time difference between the pulse-off time of the first power signal and the pulse-on time of the second power signal.

18. 10. The method of claim 1, wherein generating measurement data comprises using a single measurement device to measure pulses in the plasma from a train of multiple plasma pulses delivered to the plasma processing chamber.

19. generating the measurement data includes measuring an optical emission spectrum of the plasma while measuring (a) the power, voltage, or current of the first power signal, (b) the power, voltage, or current of the second power signal, and / or (c) the power, voltage, or current of a harmonic of the first power signal or the second power signal, and the method compares the optical emission spectrum of the plasma with (a) the power, voltage, or current of the first power signal, (b) the power, voltage, or current of the second power signal, or (c) the power, voltage, or current of the harmonic of the first power signal or the second power signal; The method of claim 1 further comprising:

20. 10. The method of claim 1, wherein the generating measurement data comprises measuring the chamber pressure in the plasma processing chamber, and wherein the adjusting comprises adjusting the chamber pressure during the plasma processing to control one or more properties of the plasma.

21. 1. A system for processing a substrate, comprising: a plasma processing chamber configured to process the substrate with a pulsed plasma process; one or more power sources coupled to supply a first power signal including a first set of timing parameters specifying a pulse-on time and a pulse-off time of the first power signal and a second power signal including a second set of timing parameters specifying a pulse-on time and a pulse-off time of the second power signal to the plasma processing chamber so as to generate a plasma in the plasma processing chamber; one or more measurement devices configured to generate measurement data corresponding to the first power signal, the second power signal, the plasma, or chamber pressure, the measurement data being generated in real time during performance of the pulsed plasma process in the plasma processing chamber; a controller coupled to the one or more power sources and the one or more measurement devices, wherein in response to the measurement data, the controller is configured to adjust one or more timing parameters of the first power signal, one or more timing parameters of the second power signal, and / or the chamber pressure to modify a pulse width of the first power signal and / or a pulse width of the second power signal to control one or more plasma characteristics during the plasma processing; A system including:

22. 22. The system of claim 21, wherein the first power signal and the second power signal are supplied by a single power source.

23. 22. The system of claim 21, wherein the first power signal is provided by a first power source and the second power signal is provided by a second power source different from the first power source.

24. The measurement data is the power, voltage, current and / or phase of the first power signal; the power, voltage or current of a harmonic of the first power signal; the power, voltage, current, and / or phase of the second power signal; the power, voltage or current of a harmonic of the second power signal; the optical intensity or emission spectrum of the plasma generated in the plasma processing chamber; the direct current voltage (Vdc) level of the plasma generated in the plasma processing chamber; and The chamber pressure in the plasma processing chamber 22. The system of claim 21, comprising one or more of:

25. 22. The system of claim 21, wherein the first power signal is a source power signal, and the controller is configured to adjust the pulse-on time of the first power signal to control a plasma density of the plasma.

26. 26. The system of claim 25, wherein the controller is configured to adjust the pulse on-time of the first power signal in real time during a cycle of the pulsed plasma treatment based on the measurement data generated by the one or more measurement devices during the cycle.

27. 27. The system of claim 26, wherein the one or more measurement devices are configured to detect a rising edge of the first power signal during the cycle of the pulsed plasma treatment, and wherein based on the rising edge of the first power signal detected by the one or more measurement devices, the controller is configured to adjust a falling edge of the first power signal during the cycle of the pulsed plasma treatment to control the pulse on time of the first power signal to maintain a predetermined plasma density.

28. 22. The system of claim 21 , wherein the second power signal is a bias power signal, and the controller is configured to adjust the pulse-on time of the second power signal to control ion flux and / or ion energy of the plasma.

29. 30. The system of claim 28, wherein the controller is configured to adjust the pulse on-time of the second power signal in real time during a cycle of the pulsed plasma treatment based on the measurement data generated during the cycle.

30. 30. The system of claim 29, wherein the one or more measurement devices are configured to detect a rising edge of the second power signal during the cycle of the pulsed plasma treatment, and based on the rising edge of the second power signal detected by the one or more measurement devices, the controller is configured to adjust a falling edge of the second power signal during the cycle of the pulsed plasma treatment to control the pulse on time of the second power signal to maintain a predetermined ion flux and / or ion energy.

31. 30. The system of claim 28, wherein if the pulse-on time of the second power signal is adjusted during a current cycle of the pulsed plasma treatment, the controller is further configured to adjust the pulse-on time and the pulse-off time of the second power signal in a next cycle of the pulsed plasma treatment based on the adjustment made during the current cycle.

32. 22. The system of claim 21, wherein one or more measurement devices are configured to measure a chamber pressure in the plasma processing chamber during the pulsed plasma processing, and wherein the controller is configured to adjust the chamber pressure during the pulsed plasma processing to maintain a specified plasma density, ion flux, and / or ion energy.

33. 1. A system for processing a substrate, comprising: a plasma processing chamber configured to process a substrate with a pulsed plasma process, the plasma processing chamber including a first power supply system and a second power supply system; a first power supply coupled to the first power supply system to supply a first power signal to generate a plasma in the plasma processing chamber, the first power supply including a first set of timing parameters defining a pulse-on time and a pulse-off time of the first power signal; a second power source coupled to the second power supply system to supply a second power signal including a second set of timing parameters specifying a pulse-on time and a pulse-off time of the second power signal; one or more measurement devices configured to generate measurement data in real time during the pulsed plasma process in the plasma processing chamber, the measurement data including: (a) off-instrument measurement data corresponding to the first power signal and / or the second power signal; and (b) on-instrument measurement data corresponding to a plasma or chamber pressure in the plasma processing chamber; a controller coupled to the first power supply, the second power supply, and the one or more measurement devices, wherein in response to the measurement data, the controller is configured to adjust one or more timing parameters of the first power signal, one or more timing parameters of the second power signal, and / or the chamber pressure to modify a pulse width of the first power signal and / or a pulse width of the second power signal to control one or more plasma characteristics during the pulsed plasma process; A system including:

34. the in-device measurement data generated by the one or more measurement devices; the optical intensity or emission spectrum of the plasma generated in the plasma processing chamber; the direct current voltage (Vdc) level of the plasma generated in the plasma processing chamber; and The chamber pressure in the plasma processing chamber 34. The system of claim 33, comprising one or more of:

35. the off-device measurement data generated by the one or more measurement devices, the power, voltage, current and / or phase of the first power signal; the power, voltage, current and / or phase of the harmonics of the first power signal; the power, voltage, current, and / or phase of the second power signal; and the power, voltage, current, and / or phase of the harmonics of the second power signal; 34. The system of claim 33, comprising one or more of:

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