Method and apparatus for improving sheath formation, evolution and pulse-to-pulse stability in radio frequency driven plasma

Abstract

The RF generator is configured to generate an RF signal. The RF signal is modulated by pulses having one or more states. During an initial state of pulse activation, the RF generator adjusts impedance matching by selecting a frequency of the RF signal. During a second state of the pulse, the RF generator adjusts impedance matching using a matching network. The first state includes controlling the RF generator to output a power burst, and the second state includes controlling the generator to output an operating power.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Patent Application No. 16 / 986,680 filed on August 6, 2020 and also claims the benefit of U.S. Provisional Application No. 62 / 886,279 filed on August 13, 2019. The entire disclosure of the above application is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure relates to a radio frequency (RF) generator system and control of the RF generator. Background Art

[0004] The prior art description provided here is to present the background of the present case in general. The work products currently named as inventors, whether described in this prior art section or in other parts of the specification, may not be the prior art at the time of the present application, and such description neither expressly nor implicitly admits that the applicant has admitted that it constitutes prior art that can be used to refute the present case.

[0005] Plasma fabrication is commonly used in semiconductor manufacturing. In plasma etching, ions are accelerated by an electric field to etch material from or deposit material onto the surface of a substrate. In a basic embodiment, the electric field is generated based on a radio frequency (RF) or direct current (DC) power signal generated by a corresponding radio frequency (RF) or direct current (DC) generator of a power delivery system. The RF power signal generated by the generator must be precisely controlled to effectively perform plasma etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The present invention provides a radio frequency generator, which includes a radio frequency power source that generates an output signal, the output signal includes a radio frequency signal modulated by pulses, and the pulses vary according to the power to be delivered to a load. The radio frequency generator includes a controller configured to control the pulses to include a plurality of states. In a first state, the controller is configured to control the radio frequency generator to output a radio frequency signal at a first power value, and control the frequency of the radio frequency signal to a first frequency to change the impedance between the radio frequency generator and the load. In a second state, the controller is configured to operate in at least one of four modes: in the first mode, the controller controls the radio frequency generator to output a radio frequency signal at a second power value and controls the frequency of the radio frequency signal without considering the impedance between the radio frequency generator and the load, wherein the first power value is a burst power and the second power value is an operating power. In the second mode, the controller controls the radio frequency generator to output a radio frequency signal at a second power value and controls the frequency of the radio frequency signal to change the impedance between the radio frequency generator and the load, wherein the first power value is a burst power and the second power value is an operating power. In the third mode, the controller controls the RF generator to output the RF signal at the second power value and controls the frequency of the RF signal without considering the impedance between the RF generator and the load, wherein the first power value exceeds the second power value. In the fourth mode, the controller controls the RF generator to output the RF signal at the second power value and controls the frequency of the RF signal to change the impedance between the RF generator and the load, wherein the first power value exceeds the second power value.

[0007] The present invention provides a radio frequency generator system, which includes a radio frequency power source that generates an output signal, the output signal includes a radio frequency signal modulated by a pulse, the radio frequency signal varies according to the power to be delivered to a load, wherein the pulse includes a plurality of states. A controller is configured to control the radio frequency generator. In a first state including a plurality of frequency grids, the controller is configured to (a) control the radio frequency generator to output a plurality of frequencies in each of the plurality of frequency grids, and the controller is configured to control the radio frequency generator to output the radio frequency signal at at least one first power value. In a second state, the controller is further configured to control the radio frequency generator to output the radio frequency signal at a second power value in mode (a).

[0008] The controller is configured to control pulses output by an RF power source. The RF power source generates an output signal, the output signal comprising an RF signal modulated by pulses, the pulses varying according to the power to be delivered to the load. In a first state, the controller is configured to control the RF generator to output the RF signal at a first power value, and to control the frequency of the RF signal to a first frequency to change the impedance between the RF generator and the load. In a second state, the controller is further configured in mode (a) to control the RF generator to output the RF signal at a second power value, and to control the frequency of the RF signal without considering the impedance between the RF generator and the load, wherein the first power value is a burst power and the second power value is an operating power.

[0009] The present invention provides a method for controlling power delivery to a load, which includes controlling an RF generator to generate an RF output signal modulated by pulses to change the power delivered to the load. The method includes, in a first state, controlling the RF generator to output an RF signal at a first power value of a first frequency to change the impedance between the RF generator and the load. The method includes, in a second state, controlling the RF signal to be output at a second power value in mode (a), and controlling the frequency of the RF signal without considering the impedance between the RF generator and the load, wherein the first power value is a burst power and the second power value is an operating power.

[0010] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and accompanying drawings.The detailed description and specific examples are intended for illustrative purposes only and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic block diagram of a power delivery system for multiple power supplies configured according to the present disclosure;

[0013] Figure 2 The waveform of the radio frequency signal and the pulse modulating the radio frequency signal;

[0014] Figure 3 is a plot of pulse, forward voltage, and reverse voltage versus time for a conventionally configured power delivery system;

[0015] Figure 4 Corresponding to Figure 3 Plot of the forward power, reverse power and output power versus time of the waveform;

[0016] Figure 5 is a Smith chart of the locus of sheath formation of impedance during a pulse at the generator output;

[0017] Figure 6 Corresponding to Figure 5 A Smith chart showing the forward power, reverse power and output power versus time;

[0018] Figure 7 is a plot of pulse, forward voltage, and reverse voltage versus time for a conventionally configured power delivery system operating in burst mode;

[0019] Figure 8 Corresponding to Figure 7 Plot of the forward power, reverse power and output power versus time of the waveform;

[0020] Fig. 9 is a Smith chart of the forward power output by the RF generator when operating in a burst mode near different phases of the Smith chart;

[0021] Fig.10 A pulse whose pulse ON time is divided into a plurality of states to define an operation mode according to the present disclosure;

[0022] Fig.11 is a plot of voltage standing wave ratio and frequency according to the principles of the present disclosure;

[0023] Fig.12 is a Smith chart of impedance versus frequency according to the principles of the present disclosure;

[0024] Fig.13 is a graph of forward voltage, reverse voltage, and output voltage of a radio frequency generator versus time for a power delivery system of a conventional configuration;

[0025] Fig.14 is a plot of forward voltage, reverse voltage, and output voltage of a radio frequency generator versus time for a power delivery system operating according to the principles of the present disclosure;

[0026] Fig.15 is a stability diagram of a power delivery system operating according to the principles of the present disclosure;

[0027] Fig.16 is a graph showing the forward power, reverse power and voltage output by a radio frequency generator when operated according to the conventional method;

[0028] Fig.17 is a diagram of a radio frequency power generator showing forward power, reverse power and voltage output by the radio frequency generator when operating according to the principles of the present disclosure;

[0029] Fig.18 is a plot of forward power, reverse power and voltage output by a radio frequency generator when operating according to the principles of the present disclosure including applying gamma blanking;

[0030] Fig.19 is a plot of forward power, reverse power and voltage output by a radio frequency generator when operating according to the principles of the present disclosure including applying PID recovery;

[0031] Fig. 20 is a plot of forward power, reverse power and voltage output by a radio frequency generator when operating according to the principles of the present disclosure including applying gamma masking and PID recovery;

[0032] Fig.21 is a plot of forward power, reverse power, and voltage output by an RF generator for operation including applying frequency-based impedance tuning to two different, sequential start-up frequencies in accordance with the principles of the present disclosure;

[0033] Fig. 22 is a plot of forward power, reverse power, and voltage output by an RF generator at a first power set point, including operation with frequency-based impedance tuning applied to two different, sequential start-up frequencies, PID recovery, gamma blanking, and power boosting between different frequencies in accordance with the principles of the present disclosure;

[0034] Fig.23 is a plot of forward power, reverse power, and voltage output by an RF generator at a second power set point, including operation with frequency-based impedance tuning applied to two different, sequential start-up frequencies, PID recovery, gamma blanking, and power boosting between different frequencies in accordance with the principles of the present disclosure;

[0035] Fig.24 is a Smith chart of impedance trajectory measured under load from pulse start to steady state for a power delivery system configured according to principles of the present disclosure;

[0036] Fig.25 is a Smith chart of impedance trajectory measured under load from pulse start to steady state for a power delivery system configured according to principles of the present disclosure;

[0037] Fig.26 is a functional block diagram of an example control module configured according to various embodiments;

[0038] Fig. 27 The figure is a flowchart showing the operation of a control system configured according to the principles of the present disclosure;

[0039] Fig.28 is an expanded diagram showing a pulse in which a pulse ON period is divided into a plurality of states to define an operation mode according to the present disclosure;

[0040] Fig.29 Figures illustrate frequency and time waveforms for implementations using bins according to various embodiments;

[0041] Fig.30 The waveform of time and frequency in the burst state of pulse is shown;

[0042] Fig.31 The waveform is a diagram showing the frequency of each frequency frame for updating the burst state of the pulse;

[0043] Fig.32 is a functional block diagram illustrating an exemplary control module configured according to various embodiments; and

[0044] Fig.33 FIG. 2 is a flowchart showing the operation of a control system configured according to the principles of the present disclosure.

[0045] In the drawings, reference characters may be repeated to identify similar and / or identical components. DETAILED DESCRIPTION

[0046] The power system may include a DC or RF power generator, a matching network, and a load (such as a processing chamber, plasma chamber, or reactor with fixed or variable impedance). The power generator generates a DC or RF power signal and is received by a matching network or impedance optimization controller or circuit. The matching network or impedance optimization controller or circuit matches the input impedance of the matching network to the characteristic impedance of the transmission line between the power generator and the matching network. This impedance matching helps to maximize the power delivered to the matching network (forward power) and minimize the power reflected from the matching network back to the power generator (reverse power). When the input impedance of the matching network matches the characteristic impedance of the transmission line and the generator, the forward power can be maximized and the reverse power can be minimized.

[0047] In a power source or power supply field, there are generally two ways to apply a power signal to a load. The first, more traditional way is to apply a continuous power signal to the load. In continuous mode or continuous wave mode, the continuous power signal is generally a constant DC or sinusoidal RF power signal that is continuously output from the power source to the load. In the continuous mode method, the power signal is a constant DC or sinusoidal output, and the amplitude and / or frequency (of the RF power signal) of the power signal can be changed to change the output power applied to the load.

[0048] The second way to apply a power signal to the load involves pulsing the RF signal instead of applying a continuous RF signal to the load. In the pulsed mode of operation, the RF signal is modulated by a modulation signal to define the envelope of the modulated power signal. The RF signal can be, for example, a sinusoidal RF signal or other time varying signal. The power delivered to the load is typically varied by varying the modulation signal.

[0049] In a typical power supply configuration, the output power applied to the load is determined using sensors that measure the forward and reflected power or the voltage and current of the RF signal applied to the load. Any set of these signals is analyzed in a control loop. This analysis determines the power value used to adjust the power supply output in order to change the power applied to the load. In a power delivery system where the load is a processing chamber or other nonlinear or time-varying load, since the applied power is partly a function of the load impedance, the changing impedance of the load will result in a corresponding change in the power applied to the load.

[0050] In systems where the manufacture of various devices relies on the introduction of power into a load to control the process, power is typically delivered in one of two configurations. In the first configuration, power is capacitively coupled to the load. Such systems are referred to as capacitively coupled plasma (CCP) systems. In the second configuration, power is inductively coupled to the load. Such systems are typically referred to as inductively coupled plasma (ICP) systems. Power coupled to the plasma can also be achieved via wave coupling at microwave frequencies. Such methods typically use Electron Cyclotron Resonance (ECR) or microwave sources. Helicon sources are another form of wave coupled source and typically operate at radio frequency frequencies similar to conventional ICP and CCP systems. The power delivery system may include at least one bias power and / or source power applied to one or more electrodes of the load. The source power typically generates the plasma and controls the plasma density, and the bias power modulates the ions formed in the sheath. The bias and source may share the same electrode or may use different electrodes, depending on various design considerations.

[0051] When a power delivery system drives a time-varying or nonlinear load such as a processing chamber or plasma chamber, the power absorbed by the overall plasma and plasma sheath results in ion density over a range of ion energies. One characteristic measure of ion energy is the ion energy distribution function (IEDF). The ion energy distribution function can be controlled by bias power. A method of generating an ion energy distribution function for a system that applies multiple RF power signals to a load by varying multiple RF signals related to amplitude, frequency, and phase. The relative amplitudes, frequencies, and phases of multiple RF power signals can also be related via Fourier series and correlation coefficients. The frequencies between multiple RF power signals can be locked, and the relative phases between multiple RF signals can also be locked. Examples of such systems can be found in U.S. Patent Nos. 7,602,127, 8,110,991, and 8,395,322, all of which are assigned to the assignee of the present case and are incorporated herein by reference.

[0052] Time-varying or nonlinear loads may be present in a variety of applications. In one application, a plasma processing system may also include components for plasma generation and control. Such components are nonlinear loads implemented as a processing chamber such as a plasma chamber or reactor. Typical plasma chambers or reactors used in plasma processing systems, such as those used in thin-film manufacturing, may use a dual power system. A power generator (source) controls the generation of plasma, and a power generator (bias) controls the ion energy. Examples of dual power systems include the systems mentioned in U.S. Patent Nos. 7,602,127, 8,110,991, and 8,395,322 referenced above. The dual power systems described in the above patents require a closed-loop control system to adjust the power supply operation to control the ion density and its corresponding ion energy distribution function.

[0053] There are a variety of methods for controlling a processing chamber, such as methods that can be used to generate a plasma. For example, in an RF power delivery system, the phase and frequency of multiple drive RF signals operating at the same or nearly the same frequency can be used to control the generation of the plasma. For RF driven plasma sources, the periodic waveforms that affect the plasma sheath dynamics and the corresponding ion energy are generally known and controlled by the frequency and associated phase interactions of the periodic waveforms. Another method in an RF power delivery system involves dual frequency control. That is, two RF frequency sources operating at different frequencies are used to power the plasma chamber to provide substantially independent control of ion and electron densities.

[0054] Another approach utilizes a wideband RF power source to drive the plasma chamber. The broadband approach presents certain challenges. The first challenge is coupling the power to the electrodes. The second challenge is that the transfer function of the generated waveform to the actual sheath voltage of the desired ion energy distribution function must be tailored for a wide-process space to support surface interactions of the material. In yet another approach, in an inductively coupled plasma system, a controlling power applied to the source electrode controls the plasma density, while controlling the power applied to the bias electrode modulates the ions to control the ion energy distribution function to provide control of the etch rate. By using control of the source electrode and the bias electrode, the etch rate can be controlled via ion density and energy.

[0055] As integrated circuit and device manufacturing continues to advance, the power requirements for controlling the manufacturing process are also increasing. For example, as storage devices are manufactured, the requirements for bias power continue to increase. The increase in power produces higher energy ions, which accelerate surface interactions, thereby increasing the etching rate and directionality of the ions. In RF systems, the increase in bias power is sometimes accompanied by a lower bias frequency requirement, while increasing the number of power sources coupled to the plasma sheath created in the plasma chamber. The increase in power at a lower bias frequency and the increase in the number of bias power sources can cause intermodulation distortion (IMD) from sheath modulation. The generation of intermodulation distortion can significantly reduce the power delivered by the source where the plasma generation occurs. U.S. Patent Application No. 10 / 821,542, filed on November 3, 2010, entitled "Pulse Synchronization by Monitoring Power in Another Frequency Band," assigned to the assignee of this case and incorporated by reference herein, describes a method for achieving pulse synchronization by monitoring power in another frequency band. In the referenced US patent application, the pulse of the second RF generator is controlled based on the detection of the pulse of the first RF generator at the second RF generator, thereby synchronizing the pulses between the two RF generators.

[0056] Figure 1 1 is a diagram illustrating a radio frequency generator or power supply system 10. The power supply system 10 includes a pair of radio frequency (RF) generators or power supplies 12a, 12b, matching networks 18a, 18b, and a load 32, such as a nonlinear load, which may be a plasma chamber, a processing chamber, etc. In various embodiments, the source RF generator 12a is referred to as a source RF generator or power supply, and the matching network 18a is referred to as a source matching network. Also in various embodiments, the RF generator 12b is referred to as a bias RF generator or power supply, and the matching network 18b is referred to as a bias matching network. It will be appreciated that reference symbols may be used for components individually or collectively, without the use of letter subscripts or prime symbols.

[0057] In various embodiments, the source RF generator 12a receives a control signal 30 from the matching network 18b, the generator 12b, or receives a control signal 30' from the bias RF generator 12b. As will be explained in more detail, the control signal 30 or 30' represents an input signal to the power supply 12a, which is indicative of one or more operating characteristics or parameters of the bias RF generator 12b. In various embodiments, the synchronization detector 34 senses the RF signal output from the matching network 18b to the load 32 and outputs a synchronization or trigger signal 30 to the power supply 12a. In various embodiments, the synchronization or trigger signal 30' may be output from the power supply 12b to the power supply 12a instead of the trigger signal 30. The difference between the trigger or synchronization signals 30, 30' comes from the effect of the matching network 18b, which may change the phase between the input signal to the matching network 18b and the output signal. Signals 30, 30' contain information about the operation of bias RF generator 12b, which in various embodiments can predictively respond to account for periodic fluctuations in impedance of plasma chamber 32 caused by bias generator 12b. In the absence of control signals 30 or 30', RF generators 12a, 12b can operate autonomously.

[0058] The RF generators 12a, 12b include corresponding RF power sources or amplifiers 14a, 14b, RF sensors 16a, 16b, and processors, controllers, or control modules 20a, 20b. The RF power sources 14a, 14b generate corresponding RF power signals 22a, 22b that are output to the respective sensors 16a, 16b. The sensors 16a, 16b receive the outputs of the RF power sources 14a, 14b and generate corresponding RF power signals f_1 and f_2. The sensors 16a, 16b also output signals that vary according to various parameters sensed from the load 32. Although the sensors 16a, 16b are shown in the corresponding RF generators 12a, 12b, the RF generators 16a, 16b may be located outside the RF power generators 12a, 12b. Such external sensing may occur at the output of the RF generator, or at the input of an impedance matching device between the RF generator and the load, or between the impedance matching device (including the inside of the impedance matching device) and the output of the load.

[0059] The sensors 16a, 16b detect operating parameters of the load 32 and output signals X and Y. The sensors 16a, 16b may include voltage, current and / or direction coupling sensors. The sensors 16a, 16b may detect (i) voltage V and current I and / or (ii) forward power P_FWD output from the corresponding power amplifiers 14a, 14b and / or RF generators 12a, 12b and 12f, and reverse or reflected power PREV received from the corresponding matching network 18a, 18b or the load 32 connected to the corresponding sensor 16a, 16b. The voltage V, current I, forward power P_FWD and reverse power PREV may be scaled and / or filtered versions of the actual voltage, current, forward power and reverse power associated with the corresponding power sources 14a and 14b. The sensors 16a, 16b may be analog and / or digital sensors. In a digital implementation, the sensors 16a, 16b may include analog-to-digital (A / D) converters and signal sampling components with corresponding sampling rates. The signals X and Y may represent either voltage V and current I or forward (or source) power P_FWD and reverse (or reflected) power PREV.

[0060] The sensors 16a, 16b generate sensor signals X, Y which are received by corresponding controllers or power control modules 20a, 20b. The power control modules 20a, 20b process the corresponding X, Y signals 24a, 26a and 24b, 26b and generate one or more feedback control signals 28a, 28b to the corresponding power sources 14a, 14b. The power sources 14a, 14b adjust the RF power signals 22a, 22b based on the received feedback control signals. In various embodiments, the power control modules 20a, 20b can control the matching networks 18a, 18b via corresponding control signals 21a, 21b, respectively. The power control modules 20a, 20b can include at least a proportional integral derivative (PID) controller or its subsets and / or a direct digital synthesis (DDS) component and / or any of the various components associated with the modules as described below.

[0061] In various embodiments, the power control modules 20a, 20b are proportional-integral-derivative (PID) controllers or subsets thereof and may include functions, processes, processors, or submodules. The feedback control signals 28a, 28b may be drive signals and may include DC offset or rail voltage, voltage or current magnitude, frequency, and phase. In various embodiments, the feedback control signals 28a, 28b may be used as inputs to one or more control loops. In various embodiments, the multiple control loops may include proportional-integral-derivative control loops for RF drive and for rail voltage. In various embodiments, the feedback control signals 28a, 28b may be used in a multiple input multiple output (MIMO) control scheme. An example of a MIMO control scheme may be found in U.S. Patent No. 10,546,724, published on January 28, 2020, entitled “Pulsed Bidirectional Radio Frequency Source / Load”, which is assigned to the assignee of the present invention and is incorporated herein by reference.

[0062] In various embodiments, the power supply system 10 may include a controller 20'. The controller 20' may be disposed external to one or both of the RF generators 12a, 12b and may be referred to as an external or shared controller 20'. In various embodiments, the controller 20' may implement one or more functions, processes or algorithms described herein with respect to one or both of the controllers 20a, 20b. Thus, the controller 20' communicates with the RF generators 12a, 12b via a pair of corresponding links 36, 38, so that data and control signals can be appropriately exchanged between the controller 20' and the RF generators 12a, 12b. For various embodiments, the controllers 20a, 20b, 20' may provide analysis and control in a distributed and collaborative manner with the RF generators 12a, 12b. In various other embodiments, the controller 20' may provide control of the RF generators 12a, 12b, eliminating the corresponding local controllers 20a, 20b.

[0063] In various embodiments, the RF power source 14a, the sensor 16a, the controller 20a, and the matching network 18a may be referred to as the source RF power source 14a, the source sensor 16a, the source controller 20a, and the source matching network 18a. Similarly, in various embodiments, the RF power source 14b, the sensor 16b, the controller 20b, and the matching network 18b may be referred to as the bias RF power source 14b, the bias sensor 16b, the bias controller 20b, and the bias matching network 18b. In various embodiments, as described above, the term "source" refers to an RF generator that generates plasma, and the term "bias" refers to an RF generator that tunes the plasma ion energy distribution function. In various embodiments, the source and bias RF power supplies operate at different frequencies. In various embodiments, the operating frequency of the source RF power supply is higher than the bias RF power supply. In various other embodiments, the source and bias RF power supplies operate at the same frequency or substantially the same frequency.

[0064] Figure 2 The diagram depicts the delivery to a Figure 1 The voltage versus time plot of the load 32 is a pulse mode operation of the load. Figure 2 In the embodiment, the RF signal 40 is modulated by the pulse 42. As shown in the period or region 44 of the pulse 42, when the pulse 42 is ON, the RF generator 12a outputs the RF signal 40. Conversely, in the period or region 46 of the pulse 42, the pulse 42 is OFF, and the RF generator 12a does not output the RF signal 40. The pulse signal 42 can be repeated at a constant duty cycle or a variable duty cycle. In addition, the pulse signal 42 does not have to be constant. Figure 2 The implementation shown is a square wave. In addition, the pulse 42 can have multiple ON and OFF regions with varying amplitudes and durations. The multiple regions can repeat in a fixed or variable period.

[0065] Figure 3 The pulsed RF signal is applied to Figure 1 Example waveforms for applications of a load 32 such as a processing chamber or a plasma chamber. Figure 3 In FIG. 5 , pulse 50 is a square wave having an ON period or region 51 and an OFF period or region 53 . Figure 3 Also shown are forward and reflected voltages, with waveform 52 representing the forward voltage and waveform 54 representing the reverse voltage. Figure 3 As can be seen in FIG. 5 , at the beginning of pulse 51, reflected voltage 54 is high and approximately equal to forward voltage 52, indicating that little or no power is reaching load 32. In the second half of the ON region 51 of pulse waveform 50, reverse voltage 54 decreases significantly relative to the forward voltage. This indicates that most of the power output by the generator is delivered to the load. Figure 3 As can be seen in FIG. 5 , the reverse voltage 54 occupies a considerable portion, approximately 50%, of the ON region 51 of the pulse waveform 50 , which means that power is delivered to the load only during the second half of the ON region 51 of the pulse waveform 50 .

[0066] Figure 4 Plots of power versus time show reflected power or reverse power 60 and forward power 58 . Figure 4 Also shown is a waveform of output power 62 , which is generally defined as the difference between forward power 58 and reverse power 60 . Figure 4 Department representation Figure 3 The reverse power 60 reaches a peak at 64 and decreases to zero over time, beginning to decrease at approximately position 66. When the reverse power 60 decreases to zero, the forward power 58 also decreases, so that the output power 62 is substantially equal to the forward power 58. Figure 4 Schematic illustration of a slowly forming sheath with considerable delay.

[0067] Figure 5 and Figure 6 The corresponding Smith chart is shown, along with a plot of power versus time as the plasma sheath evolves from a floating sheath to a steady-state RF powered sheath. The matching network is tuned to the stable portion of the pulse, and the evolution of the sheath is shown by moving the trajectory during the initial period of the pulse and ending at or near 50 ohm impedance. Figure 5 It is a Smith chart based on the detection of electrical parameters measured at the output of the RF generator. Figure 5 In FIG. 1 , the trajectory initially starts at position 70 near the outside of the Smith chart, and the impedance progresses from position 70 to position 72, which represents the gradual transition to 50 ohm impedance from near the outside of the Smith chart. Therefore, Figure 6 The transition from position 70 to position 72 representing an impedance of 50 Ohms is shown.

[0068] like Figure 6 As shown, in the transition from position 70 to 72, the forward power waveform 74 peaks at position 77 shortly after pulse initiation 70, and the reverse power waveform 76 shows a peak at position 75, but with a power less than the forward power peak 77. Waveform 78 shows the output power rapidly increasing to a substantially constant value at or near position 80. Figure 6 An exemplary illustration of a rapidly forming sheath with minimal delay.

[0069] A method of improving power delivered to a load, such as load 32, involves applying a power burst at a burst power at pulse initiation. When applying a power burst, at pulse initiation, the RF power source 14 of the RF generator 12 increases the amplitude of the RF power for a relatively short period of time to accelerate sheath formation in the plasma. After the power burst, the amplitude of the RF generator returns to a working or operating level to balance the ON region of the pulse. A successful burst can be measured from various aspects. In one aspect, sheath formation within 30 μs to 40 μs can be considered a successful burst.

[0070] Figure 7 Illustration Figure 8 The waveforms of pulses, forward voltage, reverse voltage and power over time. Figure 7 , waveform 90 represents a pulse, waveform 92 represents a forward voltage, and waveform 94 represents a reverse voltage. Figure 7 It can be seen that the reverse voltage 94 is higher at the beginning of the pulse, similar to Figure 3 The reverse voltage is 54, however, Figure 8 As shown, Figure 4 In contrast, the output power 100 starts to increase rapidly within the power burst. Regarding pulse start, the reverse voltage 94 is Figure 3 The reverse voltage 54 decreases faster, however Figure 8 As shown, Figure 4 In contrast, the output power 100 starts to increase rapidly within the power burst. Regarding pulse start, the reverse voltage 94 is Figure 3 The reverse voltage 54 decreases faster. Therefore, Figure 7 The reverse voltage 94 is higher than Figure 3 The increase is reduced over a shorter period, thereby allowing the sheath to form in a shorter time.

[0071] Figure 8 The power is plotted with respect to time. Figure 8 As shown in FIG. 1 , although the forward power 96 and the reverse power 98 reach their peak values ​​relatively quickly after the power burst 102, Figure 4 In contrast, the reverse power 98 decreases relatively quickly, resulting in a relatively fast increase in the output power 100. Figure 3 and Figure 4 and Figure 7 and Figure 8 By way of non-limiting comparison, by increasing the power by about 25% during the power burst, the output power reaches a value that causes the sheath to form about an order of magnitude faster than when no power burst is applied.

[0072] Although applying power bursts can significantly reduce the time it takes for the sheath to form, the increase in power during the burst has a negative impact on Figure 1 The RF generator 12 is thus subjected to a stress test. One benefit of the burst mode of applying power bursts is that a matching network such as the matching network 18 can be configured to provide an optimal match shortly after the burst, thereby saving time to achieve a better solution for the matching network 18. However, each power burst results in additional power being applied, and the additional power generates additional heat, thereby potentially further stressing the RF generator 12. In addition, due to Figure 7 and Figure 8 The illustrated power burst uses the auto-adjust matching function that is typically available in the matching network 18, which causes further stress on the generator because the matching network 18 is not tuned to provide a 50 ohm match during the power burst at the beginning of the pulse. Therefore, during the power burst, the RF generator 12 will be subject to additional stress because the tuning of the matching network will not have time to provide the best match and higher power must be generated to provide the higher burst power. However, some device manufacturers require the RF generator to operate in all phases or positions around the Smith chart, such as Figure 5 As shown, applying a burst can cause it to operate around a larger portion of the Smith chart.

[0073] Fig. 9 1 is an exemplary Smith chart showing the power applied relative to the position (ie, phase) of the signal applied to the load 32. It can be seen that in the Smith chart 110, the position on the Smith chart corresponds to the impedance, which in part determines the power applied to the load. Fig. 9 The magnitude of the power is not shown in the diagram, but each plotted point on the Smith chart 110 corresponds to the power applied to the load. However, one of ordinary skill in the art will appreciate that various regions of the plotted points may represent approximately the power applied to the load. Thus, for various RF generators, the regions of the Smith chart 110 may represent the optimal operating region for delivering maximum power to the load. In various embodiments, control parameters may be selected so that the RF generator operates in the optimal region and avoids suboptimal regions.

[0074] Fig.10 The diagram is similar to Figure 2 The pulse waveform 120 of the pulsed radio frequency system. Figure 2 The RF waveform 40 has been changed from Fig.10 However, those with ordinary knowledge in the art will understand that Fig.10 The system indicates such as Figure 1FIG. 1 is a pulse waveform 120 in a pulsed implementation of an RF generator system of a power delivery system 10. The ON period or region 122, 122' of the pulse waveform 120 is shown divided into a first section or state 124 including a power burst and frequency-based impedance control, and a post-burst section or state 126 including a matching network impedance control section or state. The pulse waveform 120 also includes an OFF period or region 123.

[0075] The ON region 122' of the pulse waveform 120 represents two impedance control sub-segments or sub-states 124a', 124b'. The segments or states 124, 126 may refer to the operation or control of the RF generator 12 and the matching network 18 based on time over the ON region of the pulse waveform 120. During each state, various control modes of the RF generator 12 and the matching network 18 may be achieved. Thus, the ON regions 122, 122' of the pulse waveform 120 represent at least two states, which may correspond to at least two modes of power delivery and impedance matching in the power delivery system 10. The first mode includes frequency-based impedance control occurring during state 124 when the power burst is applied. The second mode includes impedance matching network impedance control occurring during state 126 and is achieved by the matching network 18 of the power delivery system 10. The matching network impedance control tuning elements of the matching network 18 are adjusted to provide impedance matching.

[0076] In various embodiments, frequency-based impedance matching or tuning in state 124 can be implemented as automatic frequency tuning (AFT) or dynamic frequency tuning (DFT). AFT / DFT can generally be described as operating within a predetermined frequency range to control impedance matching. Examples of automatic frequency tuning and dynamic frequency tuning can be found in U.S. Patent Publication No. 8,576,013 and U.S. Patent Publication No. 9,041,471, all of which are assigned to the assignee of the present case and are incorporated herein by reference. In various embodiments, AFT / DFT can provide sufficient impedance control so that the power delivered to the load meets the power requirement without requiring burst power.

[0077] In various embodiments, the impedance may be controlled using a selected operating frequency to achieve frequency-based impedance matching or tuning, as opposed to varying the frequency within a predetermined frequency range as in AFT or DFT. In various other embodiments, frequency-based impedance matching or tuning may be achieved by selecting a frequency trajectory where the transition from a starting frequency to an ending frequency utilizes one or more predetermined intermediate frequencies to optimize the impedance matching during the transition. Following state 124, frequency-based tuning may be disabled in state 126, and impedance matching is performed through the matching network 18 using conventional matching network techniques. Such techniques include conventional matching network techniques where one or more variable reactive elements are adjusted to change the impedance at the output of the RF generator 12.

[0078] In various embodiments, and by way of example only, Figure 1 The RF frequency of one or both of the RF generators 12 may be 13.56 MHz or multiples thereof. In various other embodiments, the source RF generator may operate at 13.56 MHz or multiples thereof, and the bias RF generator may operate at or within approximately 2% of 13.56 MHz or multiples thereof.

[0079] In various embodiments, the pulse 120 may have a frequency of approximately 100 Hz. When the pulse 120 is approximately 100 Hz, the state 124 may be approximately 30 μs, however this may vary. The duration of the state 124 may be adjusted according to various design considerations. In various other embodiments, the state 124 does not require the performance of AFT or DFT frequency tuning to achieve matching. In various embodiments, the state 124 of the pulse 120 may represent a selected RF frequency that is different from the frequency at which the RF generator 12 operates during a substantial portion of the ON region 122. By way of non-limiting example, assuming that the RF generator 12 operates at 13.56 MHz in various embodiments, during the startup period, the frequency output by the RF generator 12 in the state 124 may be automatically selected by the control system. The control system may select the frequency by using a frequency recovery mode, wherein the frequency is set based on the frequency used under similar previous conditions, or the frequency may be defaulted to a user selected frequency. One method of determining the optimal startup frequency includes performing a frequency sweep at a low or lowest possible power representing the pulse startup condition and recording the frequency that results in the lowest reflected power. Furthermore, in various embodiments, frequency-based impedance tuning may be implemented on state 124 of pulse 120 with or without a power burst. That is, frequency tuning may be applied in state 124 in accordance with a power burst, wherein the power output of the RF generator is increased by increasing the amplitude of the RF signal for a predetermined time, such as 30 μs. In other embodiments, frequency-based impedance tuning may be implemented without applying a power burst.

[0080] Fig.11 and 12 Illustration Fig.11 Plotting and plotting of voltage standing wave ratio (VSWR) in Fig.12 In the Smith chart. Fig.11 VSWR is shown as a function of frequency. Waveform 130 reaches a minimum at location 132 at a frequency of approximately 13.78 MHz. Fig.12 , curve 136 shows the change in phase with respect to frequency, starting from position 138, reaching the origin at position 140, and moving along the trajectory to position 142. Thus, in a frequency sweep from about 12.8 MHz to 14.238 MHz, frequency changes change impedance, and frequency changes are both actuators of VSWR, such as Fig.11 As shown, it is also a phase actuator, such as Fig.12 Therefore, Fig.11 and Fig.12 Indicated in Fig.10 Frequency tuning during state 124 may improve impedance matching between the RF generator 12 and the load 32 .

[0081] Fig.13 and Fig.14 The waveforms are representative of example results when conventional matching network impedance control is utilized over the entire pulse, such as Fig.10 The ON area 122, such as Fig.13 shown. Fig.14 The system shows such as Fig.10 In state 124 of FIG. 1 , a combined power burst in burst power and frequency-based impedance control mode is performed, followed by a burst of power such as in FIG. Fig.10 The network impedance matching control mode in state 126 of FIG. During state 126, the frequency is selected regardless of the impedance, and in various embodiments, the frequency is selected based on the process requirements associated with the load. For each of the figures, the systems are substantially similar except for the varying modes of implementing impedance matching in multiple states.

[0082] exist Fig.13 In FIG. 1 , waveform 150 shows forward power, and waveform 152 shows reflected power. Waveform 154 shows voltage, and waveform 156 shows current. In various embodiments, in a case such as Figure 1 The forward power waveform 150 and the reverse power waveform 152 are measured at the output of the RF generator 12 of the RF generator 12, and in a Figure 1 The voltage waveform 154 and the current waveform 156 are measured at the load 32 of the load.

[0083] like Fig.13 As shown, when only using Figure 1 When the matching network 18 of the matching network achieves impedance matching, the reverse power 152 is approximately equal to the forward power 150 until the reverse power 152 at approximately the position 160 decreases to be substantially less than the forward power 150 at the position 162 . Fig.13 It also shows that the voltage 154 and current 156 applied to the load 32 are about half of the values ​​before the reverse power 152 begins to decay at position 160. After position 162, the voltage 154 and current 156 increase to about twice the voltage and current before position 162. Fig.14 In the case of a pulse 161' without a power burst, an impedance matching AF / DFT impedance tuning mode is used. It should be noted that Fig.13 The component symbols mentioned in Fig.14 Similar to the above, but with the addition of a prime indicator.

[0084] exist Fig.14In FIG. 1 , after the pulse at position 161 'is initiated, the reverse power 152' begins to decrease at position 160' and reaches a minimum at approximately position 162'. Between positions 160' and 162', it can be seen that except for the decrease in reverse power 152', the voltage 154' and the current 156' are similar to Fig.13 The voltage 154' and the current 156' increase to at least twice their values ​​before position 160'. In addition, the time between positions 161 and 162 should be noted. Fig.14 In the example, the time between the pulse activations between position 161' and position 162' is expressed as a ratio of Fig.13 The time between positions 161 and 162 is substantially shorter than the time between positions 161 and 162. In addition, it can be seen that the reverse power 152' not only decays faster, but also decays in a shorter time, as seen with respect to the shorter time period between positions 160' and 162'. On the other hand, Fig.13 There is a large time period between position 160 and position 162.

[0085] More about Fig.13 and Fig.14 , a method for automatically tuning a matching network may be implemented, such as by Figure 1 18. In the method of automatically tuning the matching network, the matching network 18 initiates impedance matching control when an RF signal is detected, rather than when a pulse is detected. The RF signal is present when the pulse is initiated. After the RF signal is detected, the matching network 18 initiates impedance matching by adjusting reactive components, such as capacitors and inductors, in the matching network 8 to adjust the impedance to improve the match between the RF generator 12 and the transmission line at the output of the matching network 18. After the pulse is no longer detected, the matching network 18 remains in its current position, anticipating that the next pulse will require a similar matching configuration. Therefore, after the ON period of the pulse ends, no RF signal is detected, and the matching network 18 remains in its current position, anticipating that the next detected RF signal will cause adjustment to approximately the current position, thereby defaulting the matching network 18 for the next detection of an RF signal. Various embodiments use one of several time delays relative to the detection of the RF ON or pulse ON to define the pulse region that the matching network 18 should tune. In various embodiments, the matching network 18 is tuned at a time after the burst and a time before the RF signal or pulse turns OFF or changes state.

[0086] Although this method does not have sudden Fig.13This may be useful when the RF generator 12 is outputting a power burst such as in state 124, where the RF generator 12 outputs a greater amount of power at the start of the pulse, and the tuning components of the matching network 18 are not in the optimal position to accommodate the increased power in the burst. After detecting the higher amplitude RF signal during the power burst, the matching network is unable to respond within the typical power burst interval, and the power burst is masked, so the matching network does not detect the power burst. Because the matching network 18 does not react during the power burst, but instead tunes to the steady state of the pulse ON time, such as in state 126, after power is turned ON, the generator will see a significant impedance mismatch. The matching network 18 requires time to adjust, and the adjustment time results in less than optimal impedance matching during the adjustment period. While the burst does provide additional power, it also adds complexity to the operation of the matching network 18. Using frequency-based tuning to perform impedance matching alleviates the problem of the matching network 18 having to adjust during the power burst, and facilitates impedance matching after the power burst.

[0087] Fig.15 A stability diagram is plotted with cable length along the horizontal axis and power set point along the vertical axis. Fig.15 The stability diagram of FIG. 1 depicts two regions, a stable region represented in the first cross-hatched line, and an unstable region represented in the second cross-hatched line. Stability is determined based on whether the reverse power is greater than or less than or equal to a predetermined percentage of the pulse. That is, when the reverse power is less than or equal to a predetermined percentage of the pulse, the sheath is stable. Conversely, when the reverse power is greater than a predetermined percentage of the pulse, the sheath is unstable. Other metrics such as reflectivity or SWR may also be used to generate similar stability diagrams.

[0088] In various configurations, cable lengths may be used to represent a measure of system stability. For example, box 176 represents system stability over seven cable lengths across multiple power set points where reflected power is less than or equal to a predetermined percentage of the pulse. Outside of box 176, for each particular cable length, at one or more power settings, each cable length exhibits a reflected power greater than a predetermined percentage of the pulse. Additionally, within box 176, stability is present not only over cable lengths, but also over multiple cable lengths at multiple powers. The cable lengths within box 176 may accommodate multiple power set points. Within box 176, corresponding three and four cable lengths may form sheaths at multiple cable lengths. Thus, one of the advantages of multi-state impedance matching is that it includes a first state and a second state, in which the RF generator outputs burst power at a frequency that allows impedance matching, and in which a matching network mode in which impedance matching occurs provides a matching network having a first state, in which the RF generator outputs burst power at a frequency that allows impedance matching, and a second state, in which the impedance matching occurs, providing ... Fig.15Stability diagram of the properties shown. Such impedance matching is improved compared to conventional impedance matching based on matching networks. It is desirable to have a wide stable operating window to ensure that small changes from unit to unit do not shift the operation into an unstable region.

[0089] Figures 16 to 25 Reference is made to any one of the RF generators 12 described in Figure 1 Operation of multi-mode impedance control over multiple states in a power delivery system 10. Fig.16 The system shows Figure 1 The output waveform of the RF generator 12. Fig.16 Two views are shown, including an upper view 180a of a first time scale and a second view 182a showing an expanded view of a bracketed portion 184a. The lower view 182a shows a 20x expanded view of the bracketed portion 184a. Fig.16 In FIG. 1 , waveform 186a represents forward power, waveform 188a represents reverse power, and waveform 190a represents Figure 1 The voltage measured at the output of the matching network 18a or 18b.

[0090] It will be appreciated that, as described above, the output power delivered to the load is a quantity represented by the difference between the forward power, such as forward power 186a, and the reverse power 188a. Fig.16 182a. The delivered power is not shown, but the voltage 190a varies according to the output power, which in turn varies according to the difference between the forward voltage 186a and the reverse voltage 188a. The forward power waveform 186a is not shown in the entire view 182a because it is covered by the voltage 190a. However, the forward power 186a varies proportionally with the voltage 190a, where an increase in the voltage 190a is consistent with an increase in the forward power 186a and / or a decrease in the reverse power 188a.

[0091] Fig.16 represents a set of baseline measurements for operating the RF generator 12 with a pulsed RF signal. Fig.16 In the control configuration, the impedance matching is controlled via the matching network 18, so that Fig.16 No frequency-based impedance matching occurs. Fig.17 The diagram is similar to Fig.16 But in Fig.16 Waveforms under different operating conditions. As usual, Fig.16 The waveform is followed by the suffix "a". Figure 16 to Figure 23 In each figure, similar waveforms will use the same component symbols with different letter suffixes. For example, view 180a refers to Fig.16 , view 180b refers to Fig.17and, for example, waveform 168a refers to Fig.16 The forward power in waveform 186b refers to Fig.17 The forward power in .

[0092] Fig.17 1 illustrates operation of a system in which frequency-based impedance tuning includes a first mode in a first state, such as state 124. In a second state, such as state 126, the power at the load is adjusted to a typical operating power, and matching network control of the impedance includes a second mode. In various embodiments, during state 126, the frequency is selected without regard to impedance, and the frequency may be selected based on process requirements associated with the load. Fig.17 It can be seen that the voltage 190b is Fig.16 This indicates that other control parameters are limiting the output power of the generator.

[0093] Fig.18 Illustrated use Fig.17 The first state of the mode control and further implements the operation of the RF generator 12a of the gamma blanking technique. Gamma (Gamma, Γ) represents the reflection coefficient of the RF generator 12 of the power delivery system 10. In the gamma blanking technique, the RF generator 12 is operated at a predetermined time interval, during which the increased power is applied without reference to the reflection coefficient of the generator. In a typical application of the RF generator 12 to power, the reflection coefficient of the Smith chart is used to determine the impedance relative to the phase and is used to limit the power. For a predetermined time interval, generally a small fraction of the entire pulse width, the power is added in the form of a power burst, and the reflection coefficient is not considered when controlling the power. When gamma blanking, the RF generator operates in a seudo-open loop manner to deliver the requested output power during the power burst, regardless of impedance matching. Quasi-open loop refers to the operation of the RF generator still working in an endless loop, in other words, it is still using data from its sensors to achieve the desired power set point, but any limitations that would limit the forward power are ignored. This essentially allows the RF generator to produce an equivalent forward power level as if operating in true open loop mode. However, due to impedance matching, the power output by the RF generator cannot reach the load. Therefore, the power delivered to the load is limited by the pulse, such as Figure 2 and 10 However, during a power burst, Figure 2 and Fig.10The pulse may not define the boundaries of the output of the RF generator, but may still define the boundaries of the power delivered to the load. Due to the impedance mismatch, the output of the RF generator is substantially higher than the power delivered to the load. As a non-limiting example, eclipse may occur in approximately 50 μs of a 1000 μs pulse. Due to other factors further described below, Fig.18 System generation and Fig.17 Similar results.

[0094] Fig.19 The system is shown based on Fig.17 The present invention relates to a method for controlling the operation of the RF generator 12 of the embodiment of the present invention, and further comprising feedforward control based on the previous operation of the RF generator 12. The RF generator 12 is controlled in part according to the operation of the generator during the previous pulse. In PID recovery, if the RF generator 12 is set to operate again using the parameters and settings from the previous state, the parameters and settings of the previous state are recovered. Such a method may be referred to as proportional integral derivative (PID) recovery. Examples of such PID recovery control can be found in U.S. Patent No. 8,952,765, U.S. Patent No. 10,049,857, and U.S. Patent No. 10,217,609, which are assigned to the assignee of the present disclosure and are incorporated by reference in the present application.

[0095] from Fig.19 As can be seen in FIG. 1 , the voltage 190d is increased in a shorter time relative to the pulse start, thereby reducing the time to fully form the plasma sheath. Therefore, in the first state, such as state 124, the combination of impedance control based on frequency tuning and feedforward control further improves the time to form the sheath relative to the pulse start. Although the feedforward method is described herein as PID feedback control, various feedforward or feedback control mechanisms can accelerate the formation of the sheath and are equally applicable herein.

[0096] Fig. 20 The system is shown based on Fig.19 The waveform of the operation of the RF generator 12 is also included as follows: Fig.18 Thus, the combination of burst power, frequency-based impedance tuning, PID recovery, and gamma blanking further improves the sheath formation time relative to pulse initiation. Fig. 20 This provides improved sheath formation time, but still results in partial collapse of the sheath, as shown by the sag in voltage 190e.

[0097] Fig.21Waveforms are shown describing the operation of the RF generator 12, wherein in a first state, the RF generator 12 applies a burst of power at startup and operates at a first frequency for a short period of time to provide frequency-based impedance tuning in the first state. In a second state following the first initial state, the RF generator 12 operates at a second frequency to provide frequency-based impedance tuning in the second state. Fig.10 Substates 124a' and 124b' of provide examples of corresponding first and second states. Next, using matching network 18, control switches to impedance tuning based on the matching network, for example, in Fig.10 Status 126'. As in Fig.21 As seen in , during startup, the plasma sheath is established shortly after the pulse is initiated. In other embodiments, frequency-based impedance tuning, such as DFT, may be enabled for states 124a' and 124b'. This approach smoothes the transitions between states to maintain power coupling to the load. The frequency during state 124b' may be fixed. Various other approaches may apply variable power on the frequency ramp of state 124b'. This enables the control system to change the power set point and frequency from the state 124a' value to the desired state 124b' value in a short period of time. Thus, power bursts and frequency-based impedance tuning are used to adjust states 124a', 124b' so that the sheath is formed in a shorter period of time, as shown in waveform 190f.

[0098] Fig. 22 and Fig.23 Waveforms are shown describing the operation of an RF generator applying a power burst and operating at a first activation frequency of the RF signal at pulse activation, during which frequency-based impedance tuning is employed (state 124a'), then applying a power burst and operating at a second frequency, during which frequency-based impedance tuning is employed (state 124b'). PID recovery is applied with gamma masking. In addition, when the frequency changes from the first frequency in state 1 to the second frequency in state 2, the power is reduced accordingly. Fig. 22 and 23 The difference is that Fig. 22 The operation of the RF generator 12 at a lower power set point is shown, and Fig.23 The series represents the operation of the RF generator 12 at a higher power set point, wherein the higher set point is approximately 50 times the lower set point. Fig. 22 and Fig.23In each of the embodiments, the combination of a power burst and a first start frequency (state 1) at pulse start and a second start frequency (state 2) after the power burst provides sheath formation with minimal delay in each state using frequency-based impedance tuning in conjunction with PID recovery control, gamma masking, and power boost. In various other methods, states 1 and 2 do not require fixed frequencies in each state, but rather can ramp the frequency from state 1 to state 2, rather than abruptly changing from a first frequency to a second frequency.

[0099] Fig.24 and Fig.25 Corresponding to Fig. 22 and 23 , and are Smith charts of the respective trajectories of the impedance from pulse strike or pulse start to pulse steady state based on the parameters detected at the load or plasma chamber. As can be seen from the Smith chart, the trajectories are similar and tend toward the plasma chamber impedance shown by the Smith chart, which is represented by circles 200g and 200h, respectively. Therefore, from Fig.24 and 25 It can be seen that in Fig.23 and 24 The control system applied in provides similar trajectories regardless of the power set point.

[0100] Fig.26 The control module 210 is a combination of Figure 1 The control module 210 may include a power generation control module portion 212, an impedance matching module portion 214, and a power tuning module portion 216. The power generation module portion 212 includes a pulse control module 218, an RF frequency control module 220, and an RF amplitude module 222. The impedance matching module portion 214 includes a frequency tuning module 224 and a matching network module 226. The power tuning module portion 216 includes a PID recovery module 230, a gamma masking module 232, and a power boost module 234. In various embodiments, the control module 170 includes one or more processors that execute program codes associated with the module portions or modules 210, 212, 214, 216, 218, 220, 222, 224, 226, 230, 232, and 234. The following about Fig.26 The method describes the operation of module portions or modules 210, 212, 214, 216, 218, 220, 222, 224, 226, 230, 232 and 234.

[0101] about Figure 1 For further definition of the structure of the controllers 20a, 20b and 20', please refer to the following Fig. 27, and the definition of the term "module" provided below. Many methods, examples and Fig.26 The various control system methods shown in the figure operate the system disclosed herein. Figure 1 The following operations are mainly described with reference to the embodiments of the present disclosure, but the operations can be easily modified to apply to other embodiments of the present disclosure. The operations can be iteratively performed. Although the following operations are shown and mainly described as being performed sequentially, one or more of the following operations can be performed while performing one or more other operations.

[0102] Fig. 27 The system represents the system used to execute, for example, Figure 1 Flowchart of a control system 240 for state / mode based impedance control of power delivery. Control begins at block 242 where initialization occurs. Control proceeds to block 244 where an RF signal, such as a 13.56 MHz signal, is activated. Control proceeds to block 246 where pulses are generated to modulate the RF signal activated at block 244. As can be seen in block 246, the generation of the pulses may include several parameters, such as those described above. Figures 1 to 25 As also shown in block 244, the pulse can be divided into a plurality of states, wherein a plurality of parameters can be set for each state. The parameters include, but are not limited to, RF frequency, RF amplitude / power, frequency tuning parameters for impedance control, impedance matching network parameters for matching network impedance control, PID recovery, gamma masking, and power boost. Next, control proceeds to block 248 where it is determined whether another pulse should be initiated. If so, control returns to block 246. If not, control proceeds to block 250 where control terminates.

[0103] Fig.28 The system shows Fig.10 The expanded view of the ON period or region of the pulse 122 or 122' of the pulse waveform 120 is referred to as the pulse region 128. Fig.10 As shown, the waveform 120 has ON regions 122, 122' and an OFF region 123. The ON region 122 of the pulse waveform 120 includes a first segment or state 124 and a second segment or state 126. Fig.10 1 , pulse 122′ has a first sub-segment or sub-state 124a′, a second sub-segment or sub-state 124b′, and a third sub-segment or sub-state 126′. Sub-states 124a′, 124b′ represent sub-segments or sub-states of state 124. Sub-states 124a′, 124b′ may be used to describe different operating modes, which may include various output parameters of the RF generator, including but not limited to RF frequency, RF amplitude, phase, and other parameters described herein.

[0104] In various embodiments, sub-states 124a', 124b' may represent a first sub-state 124a', in which the RF generator outputs a power burst at a selected frequency, and a second sub-state 124b', in which the RF generator operates in a transition mode between the first sub-state 124a' and state 126. In various embodiments, state 126 may further define the operating mode of the RF generator. In sub-state 124b', the RF generator may output the same or different power bursts and frequencies as state 124a'. In various embodiments, state 126 may represent a stable state after the operating burst mode defined by state 124. Therefore, state 126 may represent a stable state of the operating mode after the operating burst mode occurring at state 124. In various other embodiments, state 126 may include various subdivisions, such as sub-states 126a' and sub-states 126b'. Sub-state 126a' may be consistent with an operating transition mode between the operating burst mode 124 and the operating stable or working mode in sub-state 126b'. In various other embodiments, substates 126a' and 126b' may be combined into a single state represented by state 126. Likewise, substates 124a' and 124b' may be combined to define a single segment or state 124.

[0105] Substate 124a' and substate 124b' may be further subdivided into a plurality of frequency bins bx, where x generally represents any frequency bin among the plurality of frequency bins. Fig.28 As shown, substate 124a' is subdivided into multiple frequency grids, such as frequency grids ba1, ba2, ..., ban. Similarly, substate 124b' can be subdivided into multiple frequency grids bb1, bb2, ..., bbn. In various embodiments, the width and number of frequency grids can vary, so that the width of each frequency grid within substate 124a' can be the same width or a varying width. Similarly, the width and number of frequency grids of substate 124b' can be the same width or different widths. In addition, the number of frequency grids comprising substate 124a' and the number of frequency grids comprising substate 124b' can vary, and the number of frequency grids of any state or substate between pulses can vary. In addition, substates 126a' and 126b' can be subdivided into frequency grids as described above with respect to 124a', 124b', and 124.

[0106] In various embodiments, any or one of the frequency bins bx, sub-states 124a', 124b', or state 124 may define various operating modes in which various RF system control parameters may be changed. Such parameters may include the frequency, amplitude, and phase of the RF signal output by the RF generator, such as Figure 1The RF generator 12, matching network control parameters and other control parameters. In various embodiments, the width of the frequency grid can be selected so that the minimum width of the frequency grid corresponds to the maximum control loop rate of the RF generator. Since the update frequency within the frequency grid within the same pulse is limited by the control loop rate, one or more frequencies output within the frequency grid can be updated between pulses. Therefore, in various embodiments, the frequency control within the frequency grid is feedforward control, and the feedforward value within the frequency grid is updated based on the measurement of one or more previous pulses corresponding to the frequency grid.

[0107] The operating mode associated with each state may define, for example, the frequency of the RF signal output by the RF generator 12. Thus, each frequency bin bx may define a specific frequency or multiple frequencies of the RF signal output by the RF generator 12. The defined frequencies may be selected to change the impedance match between the RF generator 12 and the load 32 to control the power delivered to the load. For example, when the state 124a defines a mode in which the RF generator 12 outputs a power burst, each frequency bin ba1, ba2, ba2, ban may be assigned a specific frequency selected to adjust the impedance match between the RF generator 12 and the load 32 to control the power delivered to the load 32. In addition, in various embodiments, the state 124 or the sub-states 124a', 124b' may define an operating mode of a matching network, such as the matching network 18. As a non-limiting example, during the state 124, as described above, it is desirable to disable the operation of the matching network 18 while controlling the RF generator to output a selected power at a selected frequency defined by the mode associated with each frequency bin ba1, ba2, ba2, ban.

[0108] In various operating modes, during state 124b', the RF frequency output by the RF generator 12 may be similarly divided into frequency bins bb1, bb2, bbn. As described with respect to sub-state 124a', during state 124b', a particular operating mode may similarly disable operation of the matching network 18. In addition, as described above, states 124a', 124b' may be combined to define a single state 124. In a single state 124, state 124 may be subdivided into frequency bins bx, and the electrical parameters described above may be controlled to change the impedance match between the RF generator 12 and the load 32 to improve the power delivery to the load 32. Also as described above, during state 124, operation of the matching network 18 may be disabled so that the impedance match substantially varies according to the frequency of the RF signal output by the RF generator 12.

[0109] Refer to Tables 1 and 2 below, which show the relationship between the operating state and the mode. Table 1 lists the configured system so that Fig.28The pulse 128 includes a state 124 during which the RF generator outputs a power burst at a selected frequency and an operating state 126 in which the RF generator outputs operating power and a larger or nominal frequency. Table 1 further lists a system in which states 124, 126 are not further subdivided via substates 124' or 126', and thus state 124 is divided into frequency grids bb1, bb2, bbn. As shown in Table 1, during state 124, the RF generator outputs a power burst, and the frequency varies at frequencies f1, f2, fx, fn on consecutive frequency grids of state 124. The frequency fx in Tables 1 and 2 may represent one or more frequencies within a state or frequency grid. Table 1 also indicates that the control actuator of the mode may include frequency, power, and matching network impedance control. In various embodiments, the power or power value PB may vary between each frequency grid on state 124, or may remain constant between frequency grids. The power values ​​PB in Tables 1 and 2 may represent one or more power values ​​within a state or frequency bin. In state 124, the matching network is disabled, such as by gamma blanking, so that impedance matching is performed by selecting a frequency in each corresponding frequency bin.

[0110] Table 2 shows the states and modes of RF control, where state 124 is subdivided into substates 124a', 124b', which are further subdivided into corresponding frequency grids, as shown in Table 2. In Table 2, the frequency output by the RF generator 12 can vary according to the operating mode. For example, during substate 124a', the frequency varies with the frequency grid, while the power remains constant at PB, or burst power. Table 2 also shows that substate 126a is configured as a transition state, where the transition frequency ft and the transition power Pt are output by the RF generator 12. As described above, the burst power PB can vary between each frequency grid and between each state.

[0111]

[0112] Table 1

[0113]

[0114] Table 2

[0115] In various embodiments, each state may be named accordingly, and each parameter corresponding to each mode may be changed in a particular state, sub-state, or frequency grid, so that different frequency, power, and matching network control modes may be applied to each state. In various embodiments, both frequency-based impedance control and matching network-based impedance control may be enabled in various pulse states. In such an implementation, the frequency-based impedance control is implemented to stabilize to a nominal value within a short time of the assigned pulse state. The expected tuning time, plus some buffer time, is then used as the OFF period of the matching network. Such a configuration enables the matching network 18 to sense a stable frequency once it is enabled, thereby alleviating the need for the matching network to search when the frequency is stable. In various embodiments, the matching network 18 also incorporates a frequency tracking function.

[0116] In various embodiments, the load impedance response may be measured to tune the frequency assigned to each frequency grid or state, so that the selected RF frequency of a given frequency grid may be tuned to further minimize impedance changes and maximize power delivery. The frequency or power value may be updated for one or all states, sub-states, and frequency grids based on power delivery or impedance matching conditions. The future state outputs the adjusted frequency and power value, which is determined based on the results of the previous frequency or power value. That is, in response to the application of the bx1n, bx2n, ..., bxnn values, where n is the time interval, the values ​​of the frequency grids bx1n+1, bx2n+1, ..., bxnn+1 may be determined based on the measurement of the electrical parameters. In addition, the update of the frequency grids bx1n+1, bx2n+1, ..., bxnn+1 may be based on one or more previous system responses to n, n-1, ..., nm intervals. Therefore, the preset system of the parameters of the RF generator allows adaptive feed-forward control, thereby alleviating the problem of control loop bandwidth.

[0117] Fig.29 It is a plot of frequency versus time and includes a plurality of waveforms illustrating the operation of an RF generator, wherein one state or sub-state has four frequency bins b1, b2, b3, b4, also referred to as bin 1, bin 2, bin 3, and bin 4. Curve 252 represents corresponding waveforms 254, 256, and 258. Fig.29 Each frequency grid includes five frequency settings or values, which correspond to frequency settings or RF values ​​at specific times within the frequency grid and within the corresponding pulse.

[0118] Waveform 254 indicates that within a frequency grid, the frequency is kept constant according to the equation f_(〖BIN〗_n)=α_n, where n represents the corresponding frequency grid. For example, f_(〖BIN〗_1)=α_1 represents the constant frequency α_1 of frequency grid b1. Therefore, waveform 254 defines a constant frequency for each frequency grid bn, and the constant frequency can vary between frequency grids. Waveform 256 represents a plurality of frequencies within each frequency grid, and the frequency within each frequency grid varies linearly, and the parameters of each line segment associated with each frequency grid can vary between frequency grids. The equation describing the frequency selection can be understood as 〖f(t)〗_(〖BIN〗_n)=α_n+β_n t, where n represents a specific frequency grid and t is time. Therefore, each frequency grid has an offset frequency and slope defined according to a_n and β_n, respectively. Waveform 258 shows that the frequency with any particular bin varies from pulse to pulse according to [f(t)]_([BIN]_n)=[f(t)]_n. Thus, the frequency setting of waveform 258 depends on the particular bin n and varies according to the function defined for each corresponding bin.

[0119] Fig.30 270 is a graph showing a plurality of plots of time versus frequency. Time along the horizontal axis is associated with the position of a state, sub-state, or frequency bin. The vertical axis represents frequency, such that the plot of time versus frequency represents the frequency set point selected to improve impedance matching. In various embodiments, the frequency set point for each frequency bin may be determined empirically, individually, or in conjunction with an iterative process. Waveform 272 represents a set of frequencies for an RF generator configured to output 50W. Waveform 274 is a plot of time versus frequency for an RF generator configured to output 100W. Waveform 276 is a plot of time versus frequency for an RF generator configured to output 300W. Waveform 278 is a plot of time versus frequency for an RF generator configured to output 600W. Similarly, waveform 280 is a plot of frequency versus time for an RF generator configured to output 1,200W. In various embodiments, the vertical axis may represent approximately 10+ / -5% of the center frequency of operation.

[0120] Fig.31 is a plot of the time sample index versus the reflection coefficient squared, also called reflectivity, and represents the locus of tuning the frequency to obtain the best impedance match. Fig.31 In an iterative learning method, a burst state such as state 124a is divided into four (n=4) sub-segments or frequency bins, and a predetermined number of time samples are obtained for each frequency bin. Within each frequency bin, the frequency varies linearly. In one method, the iterative learning model adjusts the slope and offset of the line segment in each frequency bin to minimize the reflection coefficient and thereby maximize the output power. Fig.31Each of the curves 292, 294, 296, 298, and 300 of FIG. 2 represents a corresponding number of pulses. That is, in various embodiments, the waveforms 292, 294, 296, 298, and 300 represent 1, 10, 20, 25, and 30 pulses, respectively.

[0121] Fig.32 1 is a functional block diagram of an example control module configured according to various embodiments. Fig.32 middle, Fig.26 Similar component symbols will be in Fig.32 Therefore, Fig.32 The control module 210' and Fig.26 Configured similarly, and the above also applies here. Fig.32 A frequency grid updating module 228 is also included, which is configured to update the frequency value or other electrical parameters for each state, sub-state or frequency grid bx mentioned above.

[0122] Fig.33 The system indicates Figure 1 Flow diagram of a control system 240 for performing impedance control of a power delivery system. Fig.32 The configuration is similar to Fig. 27 , and similar component symbols will be used to represent similar functions. Fig.33 The flow control system 240' is configured similar to Fig. 27 260. The control system 240 is similar and includes a frequency grid update portion 260. The frequency grid update portion 260 includes a block 262 that determines the impedance match for the frequency grid bx. Once the impedance match corresponding to the frequency grid bx is determined, a block 264 determines whether the impedance match for the particular frequency grid bx has improved. If the impedance match has improved, the block 260 updates the frequency of the frequency grid bx so that future iterations of the control system 240 can use the updated frequency. Returning to block 264, if the match has not improved, the update does not occur, as shown in block 268.

[0123] The above description is illustrative only and is not intended to limit the present invention, its application or use. The broad teachings of the present invention can be implemented in various forms. Therefore, although the present invention includes specific examples, the true scope of the present invention should not be so limited, because other modifications to the accompanying drawings, specifications and attached claims will become apparent. It should be understood that one or more steps in the method can be performed in different orders (or simultaneously) without changing the principles of the present invention. Further, although each embodiment is described as having certain features above, any one or more of those features described with respect to any embodiment of the present invention can be implemented and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the configuration of one or more embodiments to each other is still within the scope of the present invention.

[0124] Spatial and functional relationships between components (e.g., between modules, circuit components, semiconductor layers, etc.) are described using a variety of terms, including "connected," "joined," "coupled," "adjacent," "next to," "on," "above," "below," and "disposed." Unless explicitly described as "directly," when describing a relationship between a first component and a second component in the above disclosure, the relationship can be a direct relationship, in which there are no other intervening components between the first component and the second component, but can also be an indirect relationship, in which there are one or more intervening components (either spatially or functionally) between the first component and the second component. As used herein, the phrase "at least one of A, B, and C" should be interpreted as meaning a logical "A OR B OR C," using a non-exclusive logical "OR," and should not be interpreted as meaning "at least one of A, at least one of B, and at least one of C."

[0125] In the diagram, as indicated by the arrows, the direction of the arrows generally indicates the continuity of the messages (such as data or instructions) of interest to the diagram. For example, when component A and component B exchange various messages, but the messages sent from component A to component B are related to the diagram, the arrow can point from component A to component B. This unidirectional arrow does not mean that there are no other messages sent from component B to component A. Further, for the messages sent from component A to component B, component B can send a request for the message or a receipt confirmation to component A.

[0126] In this case, including the following definitions, the term "module" or the term "controller" can be replaced with the term "circuit". The term "module" can refer to a part of or include: an application-specific integrated circuit (ASIC); a digital, analog or mixed digital / analog discrete circuit; a digital, analog or mixed digital / analog integrated circuit; a combined logic circuit; a field-programmable gate array (FPGA); a processor circuit (shared, dedicated or group) that executes code; a memory circuit (shared, dedicated or group) that stores the code executed by the processor circuit; other suitable hardware components that provide the described functions; or a combination of some or all of the above, such as in a system-on-chip.

[0127] The modules of the present invention can include one or more interface circuits. In some instances, the interface circuit can include a wired or wireless interface that is connected to a local area network (LAN), a network, a wide area network (WAN), or a combination thereof. The functionality of any given module of the present invention can be distributed among multiple modules connected via the interface circuits. For example, multiple modules can allow for load balancing. In further instances, a server (also referred to as a remote or cloud) module can perform some functions on behalf of a client module.

[0128] As used above, the term program code can include software, firmware and / or microprogram code, and refers to programs, procedures, functions, classes, data structures and / or objects. A shared processor circuit includes a single processor circuit that executes some or all program code from multiple modules. A combined processor circuit includes a processor circuit that is combined with additional processor circuits to execute some or all program code from one or more modules. References to multiple processor circuits include multiple processor circuits on discrete chips, multiple processor circuits on a single chip, multiple cores of a single processor circuit, multiple lines of a single processor circuit, or a combination of the above. A shared memory circuit includes a single memory circuit that stores some or all program code from multiple modules. The term combined memory circuit includes a memory circuit that is combined with additional memory to store some or all program code from one or more modules.

[0129] The term memory circuit is a subset of computer-readable media. As used herein, computer-readable media does not include transient electrical or electromagnetic signals propagated through a medium (such as on a carrier wave); computer-readable media can therefore be considered tangible and non-transitory. Non-limiting examples of non-transitory, tangible computer-readable media are non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or shielded read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital magnetic tape or hard disk drives), and optical storage media (such as compact discs, laser discs, or Blu-ray discs).

[0130] In this application, a device unit described as having certain properties or performing certain operations is specifically configured to have those certain properties and to perform those certain operations. In particular, a description of a component performing an action refers to the configuration of the component to perform the action. Configuration of a component may include programming the component, such as by writing instructions on a non-transitory tangible computer-readable medium associated with the component.

[0131] The apparatus and methods described in this case can be implemented in part or in whole by a dedicated computer, which is created by configuring a general-purpose computer to execute one or more specific functions contained in a computer program. The functional blocks, flow chart blocks and other components described above are software specifications, which can be translated into a computer program by the routine work of a skilled technician or programmer.

[0132] A computer program comprises processor executable instructions stored on at least one non-transitory, tangible computer readable medium. A computer program can also comprise or rely on stored data. A computer program can comprise a basic input / output system (BIOS) that interacts with the hardware of a special purpose computer, device drivers that interact with specific devices of a special purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0133] The computer program can include: (i) parsing of descriptive text, such as HTML (Hypertext Markup Language), XML (Extensible Markup Language) or JSON (JavaScript Object Notation), (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code executed by a decoder, (v) source code compiled and executed by a real-time compiler, etc. By way of example only, programs from languages ​​including C, C++, C#, Objective C, Swift, Haskell, Go, SQL, R, Lisp, Fortran, Perl, Pascal, Curl, OCaml, HTML5 (Hypertext Markup Language 5), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK, and It is written according to the syntax of the language.

Claims

1. A radio frequency generator, comprising: an RF power source generating an output signal comprising an RF signal modulated by a pulse that varies according to the power to be delivered to a load; and A controller configured to control the pulse to include a plurality of states, wherein In a first state, the controller is configured to control the RF generator to output the RF signal at a first power value and control the frequency of the RF signal to a first frequency to change the impedance between the RF generator and the load; and In a second state, the controller is further configured in at least one of the following modes: (a) controlling the RF generator to output the RF signal at a second power value, and controlling the frequency of the RF signal without considering the impedance between the RF generator and the load; wherein the first power value is a burst power, and the second power value is an operating power; (b) controlling the RF generator to output the RF signal at the second power value, and controlling the frequency of the RF signal to change the impedance between the RF generator and the load; wherein the first power value is the burst power, and the second power value is the operating power; (c) controlling the RF generator to output the RF signal at the second power value and controlling the frequency of the RF signal without considering the impedance between the RF generator and the load, wherein the first power value exceeds the second power value; or (d) controlling the RF generator to output the RF signal at the second power value and controlling the frequency of the RF signal to change the impedance between the RF generator and the load; wherein the first power value exceeds the second power value.

2. The RF generator of claim 1, wherein in mode (b) and mode (d), the frequency of the RF signal varies within a frequency range according to the impedance between the RF generator and the load.

3. The RF generator of claim 1, wherein in mode (a) and mode (b), the first power value exceeds the boundary of the pulse, and the second power value is limited by the pulse.

4. The RF generator of claim 1, wherein the first state and the second state occur relative to the start of the pulse, and the first state occurs at the start of the pulse and the second state occurs after the first state is completed. 5 . The RF generator of claim 1 , wherein the controller is further configured to output a signal to activate operation of a matching network between the RF generator and the load.

6. The RF generator of claim 1, wherein in mode (a) and mode (c), the controller is further configured to apply gamma blanking when outputting the first power value.

7. An RF generator as described in claim 1, wherein the first state includes a plurality of frequency grids, and the controller is configured to control the RF generator of each of the plurality of frequency grids to output the first frequency based on a selected frequency associated with each of the plurality of frequency grids, wherein the selected frequency associated with each of the plurality of frequency grids varies relative to at least one pair of the plurality of frequency grids.

8. The RF generator of claim 7, wherein the controller is configured to control the RF generator of each of the plurality of frequency grids to output the first power value based on a selected power value associated with each of the plurality of frequency grids, wherein the selected power value associated with each of the plurality of frequency grids varies relative to at least one pair of the plurality of frequency grids.

9. The RF generator of claim 7, wherein the selected frequency associated with each of the plurality of frequency bins of a next pulse is updated based on at least one of an impedance match between the RF generator and the load and a power delivered to the load by at least one previous pulse.

10. An RF generator as described in claim 7, wherein the selected frequency associated with each of the plurality of frequency grids of a next pulse is updated based on linearly changing the frequency within each of the plurality of frequency grids and adjusting the slope and offset of the line segment defining the frequency change to minimize the impedance between the RF generator and the load.

11. The RF generator of claim 1 , wherein the controller is further configured to control the pulse to include a third state, wherein the controller is configured to control the RF generator to output the RF signal at a third power value and control the frequency of the RF signal to a second frequency, wherein at least one of the third power values ​​is not equal to one of the first power value or the second power value, and the second frequency is not equal to the first frequency.

12. A radio frequency generator system, comprising: an RF power source generating an output signal comprising an RF signal modulated by a pulse, the RF signal varying according to power to be delivered to a load, wherein the pulse comprises a plurality of states; and a controller configured to control the RF generator, wherein In a first state including a plurality of frequency bins, the controller is configured to (a) control the RF generator to output a plurality of frequencies in each of the plurality of frequency bins, and the controller is configured to control the RF generator to output the RF signal at at least a first power value; and In a second state, the controller is further configured to control the RF generator to output the RF signal at a second power value in mode (a), wherein The controller is configured to control the RF generator to output a plurality of power values ​​in each of the plurality of frequency bins, wherein the plurality of power values ​​vary with respect to at least one pair of the plurality of frequency bins.

13. The RF generator system of claim 12, wherein the at least one first power value and the second power value are limited by the pulse.

14. The RF generator system of claim 12, wherein the at least one first power value is a burst power, the second power value is a working power, the burst power exceeds a boundary of the pulse, and the second power value is limited by the pulse.

15. The RF generator system of claim 12, wherein in the second state, the controller is further configured in at least one of the following modes: (a) further controlling the radio frequency generator to output the plurality of frequencies in each of the plurality of frequency bins as a plurality of pre-selected frequencies; (b) controlling the RF generator to output the RF signal at the second power value, and controlling the corresponding frequency associated with each of the plurality of frequency bins to change the impedance between the RF generator and the load, wherein the first power value is a burst power and the second power value is an operating power; (c) controlling the RF generator to output the plurality of frequencies within each of the plurality of frequency bins as a plurality of preselected frequencies, wherein the first power value exceeds the second power value; or (d) controlling the RF generator to output the RF signal at the second power value and controlling a corresponding frequency associated with each of the plurality of frequency bins to change an impedance between the RF generator and the load, wherein the first power value exceeds the second power value.

16. The RF generator system of claim 15, wherein in mode (c) and mode (d), the at least one first power value and the second power value are limited by the pulse.

17. The RF generator system of claim 15, wherein in mode (a) and mode (b), the at least one first power value exceeds a boundary of the pulse, and the second power value is limited by the pulse.

18. The RF generator system of claim 15, wherein in mode (a) and mode (c), the controller is further configured to apply gamma blanking when outputting the at least one first power value.

19. The RF generator system of claim 15, wherein in mode (b) and mode (d), the plurality of frequencies within each of the plurality of frequency bins vary within the range of each corresponding frequency according to the impedance between the RF generator and the load.

20. The RF generator system of claim 12, wherein the first state and the second state occur relative to the start of the pulse, and the first state occurs at the start of the pulse, and the second state occurs after the first state is completed.

21. The RF generator system of claim 12, wherein the controller is further configured to output a signal to activate operation of a matching network between the RF generator and the load.

22. The RF generator system of claim 12, wherein the multiple frequencies within each of the multiple frequency grids of a next pulse are updated based on at least one of the impedance between the RF generator and the load and the power delivered to the load by at least one previous pulse.

23. The RF generator system of claim 12, wherein the multiple frequencies within each of the multiple frequency grids of the next pulse are updated by linearly changing the frequency within each of the multiple frequency grids and adjusting the slope and offset of the line segment defining the frequency change.

24. The RF generator system of claim 12, wherein the controller is further configured to control the pulse to include a third state, wherein the controller is configured to control the RF generator to output the RF signal at a third power value and control the frequency of the RF signal to a second frequency, wherein at least one of the third power values ​​is not equal to the first power value or one of the second power values, and the second frequency is not equal to a corresponding frequency associated with each of the plurality of frequency grids.

25. A controller configured to control pulses output by a radio frequency generator, wherein the radio frequency generator is configured to generate an output signal comprising a radio frequency signal modulated by a pulse, the pulse varying according to power to be delivered to a load, wherein In a first state, the controller is configured to control the RF generator to output the RF signal at a first power value and control the frequency of the RF signal to a first frequency to change the impedance between the RF generator and the load; and In a second state, the controller is further configured in mode (a) to control the RF generator to output the RF signal at a second power value and to control the frequency of the RF signal without considering the impedance between the RF generator and the load, wherein the first power value is a burst power and the second power value is an operating power.

26. The controller of claim 25, in mode (a) or one of the following modes, further configured to: (b) controlling the RF generator to output the RF signal at the second power value, and controlling the first frequency of the RF signal to change the impedance between the RF generator and the load, wherein the first power value is the burst power, and the second power value is the operating power; (c) controlling the RF generator to output the RF signal at the second power value and controlling the first frequency of the RF signal without considering the impedance between the RF generator and the load, wherein the first power value exceeds the second power value; or (d) controlling the RF generator to output the RF signal at the second power value and controlling the first frequency of the RF signal to change the impedance between the RF generator and the load, wherein the first power value exceeds the second power value.

27. The controller of claim 26, wherein in mode (b) and mode (d), the frequency of the RF signal varies within the first frequency range according to the impedance between the RF generator and the load.

28. The controller of claim 26, wherein in mode (a) and mode (b), the first power value exceeds a boundary of the pulse, and the second power value is limited by the pulse.

29. The controller of claim 26, wherein the first state and the second state occur relative to the start of the pulse, and the first state occurs at the start of the pulse and the second state occurs after the first state is completed.

30. A controller as described in claim 25, wherein the first state includes a plurality of frequency grids, and the controller is configured to control the RF generator of each of the plurality of frequency grids to output the first frequency based on a selected frequency associated with each of the plurality of frequency grids, wherein the selected frequency associated with each of the plurality of frequency grids varies relative to at least one pair of the plurality of frequency grids.

31. A controller as described in claim 30, wherein the controller is configured to control the RF generator of each of the plurality of frequency grids to output the first power value based on a selected power value associated with each of the plurality of frequency grids, wherein the selected power value associated with each of the plurality of frequency grids varies relative to at least one pair of the plurality of frequency grids.

32. A controller as described in claim 31, wherein the selected frequency associated with each of the plurality of frequency bins of a next pulse is updated based on at least one of an impedance match between the RF generator and the load and a power delivered to the load by at least one previous pulse.

33. A method of controlling power delivery to a load, comprising: controlling a radio frequency generator to generate a radio frequency signal modulated by a pulse to change the power delivered to the load; In a first state, the RF generator is controlled to output the RF signal at a first power value at a first frequency to change the impedance between the RF generator and the load; and In a second state, in mode (a), the RF signal is controlled to be output at a second power value, and the frequency of the RF signal is controlled without considering the impedance between the RF generator and the load, wherein the first power value is a burst power and the second power value is an operating power.

34. The method of claim 33, wherein in the second state, the control is mode (a) or one of the following modes: (b) outputting the RF signal at the second power value, and controlling the frequency of the RF signal to change the impedance between the RF generator and the load, wherein the first power value is the burst power, and the second power value is the operating power; (c) outputting the RF signal at the second power value and controlling the frequency of the RF signal without considering the impedance between the RF generator and the load, wherein the first power value exceeds the second power value; or (d) outputting the RF signal at the second power value and controlling the frequency of the RF signal to change the impedance between the RF generator and the load, wherein the first power value exceeds the second power value.

35. The method of claim 34, wherein the first state and the second state occur relative to the start of the pulse, and the first state occurs at the start of the pulse and the second state occurs after the first state is completed.

36. A method as claimed in claim 33, wherein the first state includes a plurality of frequency grids, and a controller is configured to control the RF generator of each of the plurality of frequency grids to output the first frequency based on a selected frequency associated with each of the plurality of frequency grids, wherein the selected frequency associated with each of the plurality of frequency grids varies relative to at least one pair of the plurality of frequency grids.

37. A method as claimed in claim 36, wherein the controller is configured to control the RF generator of each of the plurality of frequency grids to output the first power value based on a selected power value associated with each of the plurality of frequency grids, wherein the selected power value associated with each of the plurality of frequency grids varies relative to at least one pair of the plurality of frequency grids.

38. A method as claimed in claim 37, wherein the selected frequency associated with each of the plurality of frequency bins of a next pulse is updated based on at least one of an impedance match between the RF generator and the load and a power delivered to the load by at least one previous pulse.

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