Degaussing Coil for Improving Linearity of Current Ratio in Plasma Processing System

Abstract

The RF generator has an RF power source configured to generate an output signal. The power divider is configured to receive the output signal and generate a plurality of split signals. The degaussing circuit is configured to receive the plurality of split signals. The degaussing circuit is configured to include a plurality of inductances corresponding to the plurality of split signals. The plurality of inductances are configured to reduce an effect of mutual impedance of the ICP chamber in series with the plurality of inductances such that a ratio between pairs of the plurality of split signals changes substantially linearly as one of the pairs of the plurality of split signals changes.

Description

Technical Field

[0002] The present disclosure relates to an RF generator system and the control of an RF generator.

Background Art

[0003] Plasma manufacturing is frequently used in semiconductor manufacturing. In plasma manufacturing, ions are accelerated by an electric field to etch material from the surface of a substrate or deposit material on the surface of a substrate. In one basic implementation, the electric field is generated based on an RF power signal or a DC power signal generated by each radio frequency (RF) generator or direct current (DC) generator of a power delivery system. The power signal generated by the generator is precisely controlled to effectively perform plasma etching.

[0004] The background description provided herein is for the purpose of generally presenting the content of the present disclosure. The achievements of the inventors whose current names are listed up to the scope described in this background section, as well as aspects of this specification that may not be eligible as prior art at the time of filing, are not admitted as prior art to the present disclosure, either explicitly or implicitly.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Means for Solving the Problems

[0006] In some embodiments, the techniques described herein relate to an RF generator including an RF power source configured to generate an output signal, a power splitter configured to receive the output signal and generate a plurality of split signals, and a demagnetization circuit configured to receive the plurality of split signals, the demagnetization circuit including a plurality of inductances corresponding to the plurality of split signals, wherein the plurality of inductances are configured to reduce the influence of the mutual impedance of the ICP chamber in series with the plurality of inductances such that the ratio between pairs of the plurality of split signals changes substantially linearly as one of the pairs of the plurality of split signals changes.

[0007] In some embodiments, the techniques described herein relate to an RF generator, wherein the plurality of inductances can be one of an inductance having a coil or an inductive inductance by conducting current through an electrical conductor.

[0008] In some embodiments, the techniques described herein relate to an RF generator, wherein the demagnetization circuit includes a plurality of outputs, the plurality of outputs corresponding to each one of a plurality of antennas of the ICP chamber, and the combined mutual inductance of the plurality of inductances corresponding to the plurality of split signals is substantially equal to the combined mutual inductance of the plurality of antennas of the ICP chamber.

[0009] In some embodiments, the techniques described herein further relate to an RF generator including a matching network configured to receive an output signal from the RF power source and provide the output signal to the power splitter, the matching network being configured to provide impedance matching with the RF power source.

[0010] In some embodiments, the techniques described herein relate to an RF generator, wherein the demagnetization circuit is disposed between the power splitter and the load.

[0011] In some embodiments, the techniques described herein relate to an RF generator in which a load is disposed between a demagnetization circuit and a power splitter.

[0012] In some embodiments, the techniques described herein relate to an RF generator in which there are two inductances, the demagnetization circuit has an inner inductance and an outer inductance, the inner inductance corresponds to an inner coil of an ICP chamber, and the outer inductance corresponds to an outer coil of the ICP chamber.

[0013] In some embodiments, the techniques described herein relate to an RF generator in which there are three inductances, the demagnetization circuit has an inner inductance, an intermediate inductance, and an outer inductance, the inner inductance corresponds to an inner coil of an ICP chamber, the intermediate inductance corresponds to an intermediate coil of the ICP chamber, and the outer inductance corresponds to an outer coil of the ICP chamber.

[0014] In some embodiments, the techniques described herein relate to an RF generator including an RF power source configured to generate an output signal, a power splitter configured to receive the output signal and generate a plurality of split signals, and a demagnetization circuit configured to receive the plurality of split signals, the demagnetization circuit including a plurality of coils configured to correspond to the plurality of split signals, wherein the plurality of coils are configured to reduce the influence of the mutual impedance of the ICP chamber in series with the plurality of inductances such that the ratio between pairs of the plurality of split signals changes substantially linearly as one of a pair of the plurality of split signals changes.

[0015] In some embodiments, the techniques described herein relate to an RF generator in which the demagnetization circuit includes a plurality of outputs, the plurality of outputs corresponding to each one of a plurality of antennas of an ICP chamber, and the combined mutual inductance of the plurality of coils corresponding to the plurality of split signals is substantially equal to the combined mutual inductance of the plurality of antennas of the ICP chamber.

[0016] In some embodiments, the techniques described herein relate to an RF generator that further includes a matching network configured to receive an output signal from an RF power source and provide the output signal to a power splitter, the matching network being configured to provide impedance matching with the RF power source.

[0017] In some embodiments, the techniques described herein relate to an RF generator in which a demagnetization circuit is disposed between the power splitter and the load.

[0018] In some embodiments, the techniques described herein relate to an RF generator in which the load is disposed between the demagnetization circuit and the power splitter.

[0019] In some embodiments, the techniques described herein relate to an RF generator in which the number of coils is two, the demagnetization circuit has an inner coil and an outer coil, the inner coil corresponds to the inner coil of the ICP chamber, and the outer coil corresponds to the outer coil of the ICP chamber.

[0020] In some embodiments, the techniques described herein relate to an RF generator in which the number of coils is three, the demagnetization circuit has an inner coil, an intermediate coil, and an outer coil, the inner coil corresponds to the inner coil of the ICP chamber, the intermediate coil corresponds to the intermediate coil of the ICP chamber, and the outer coil corresponds to the outer coil of the ICP chamber.

[0021] In some aspects, the techniques described herein relate to a demagnetization circuit for an ICP system that includes a first inductance configured to receive a first RF signal and electrically connected to a first antenna of an ICP chamber, and a second inductance configured to receive a second RF signal and electrically connected to a second antenna of the ICP chamber. The first inductance and the second inductance are configured to reduce the effect of the mutual impedance of the ICP chamber in series with the plurality of inductances such that the ratio between the first RF signal and the second RF signal changes substantially linearly as one of the first RF signal or the second RF signal changes.

[0022] In some aspects, the techniques described herein relate to a demagnetization circuit for an ICP system, where the first inductance can be one of a first coil having an inductance or a first inductive inductance by conducting current through a first electrical conductor, and the second inductance can be one of a second coil having an inductance or a second inductive inductance by conducting current through a second electrical conductor.

[0023] In some aspects, the techniques described herein relate to a demagnetization circuit for an ICP system, where the combined mutual inductance of the first inductance and the second inductance is substantially equal to the combined mutual inductance of the first antenna and the second antenna of the ICP system.

[0024] In some aspects, the techniques described herein relate to a demagnetization circuit for an ICP system, where the demagnetization circuit is disposed between a power splitter and a load.

[0025] In some aspects, the techniques described herein relate to a demagnetization circuit for an ICP system, where the load is disposed between the demagnetization circuit and the power splitter.

[0026] Further applicable areas of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

[0027] The present disclosure will be more fully understood from the detailed description and the accompanying drawings.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0029] In the drawings, reference numerals may be reused to identify similar and / or identical elements.

[0030] A power system may include a DC or RF generator or DC or RF oscillator, a matching network, and a load (such as a process chamber, plasma chamber, or reactor having a fixed or variable impedance). The generator generates a DC or RF power signal, which is received by the matching network or an 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 generator and the matching network. Impedance matching helps to maximize the amount of power transferred to the matching network (the "forward power") and minimize the amount of power reflected from the matching network back to the generator (the "reverse power" or "reflected 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.

[0031] In the field of power supplies or power delivery, typically, there are two techniques for applying a power signal to a load. The first, more traditional technique is to apply a continuous power signal to the load. In continuous mode or continuous wave mode, the continuous power signal is typically a constant DC power signal or a sinusoidal RF power signal continuously output by a power source to the load. In the continuous mode technique, the power signal assumes a constant DC output or sinusoidal output, and the amplitude and / or (for an RF power signal) frequency of the power signal can be changed to vary the output power applied to the load.

[0032] The second technique for applying a power signal to a load involves pulsing the RF signal rather than applying a continuous RF signal to the load. In pulse operating mode, the RF signal is modulated by a modulation signal to define an envelope for 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 changed by varying the modulation signal.

[0033] In a typical power supply configuration, the output power applied to a load is determined by measuring the forward power and reflected power, or the voltage and current of the RF signal applied to the load using a sensor. Any set of these signals is analyzed in a control loop. The analysis is typically used to determine the power value used to adjust the output of the power supply to vary the power applied to the load. In a power delivery system where the load is a process chamber or other non-linear or time-varying load, changing the impedance of the load causes a corresponding change in the power applied to the load because the applied power is, in part, a function of the load impedance.

[0034] In systems where the manufacture of various devices depends on the introduction of power to a load to control the manufacturing process, the power is typically delivered in one of two configurations. In the first configuration, the power is capacitively coupled to the load. Such a system is called a capacitively coupled plasma (CCP) system. In the second configuration, the power is inductively coupled to the load. Such a system is typically called an inductively coupled plasma (ICP) system. Power coupling to the plasma can also be achieved by wave coupling at microwave frequencies. Such techniques typically use electron cyclotron resonance (ECR) or a microwave source. A helicon source is another form of wave coupling source and typically operates at RF frequencies similar to those of 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 a plasma and controls the plasma density, and the bias power modulates the ions in the formation of the sheath. The bias and source may share the same electrode or use separate electrodes according to various design considerations.

[0035] When a power delivery system drives a time-varying or non-linear load, such as a process chamber or a plasma chamber, the power absorbed by the bulk plasma or the plasma sheath results in an ion density having a range of ion energies. One characteristic measure of ion energy is the ion energy distribution function (IEDF). The ion energy distribution function (IEDF) can be controlled using bias power. One way to control the IEDF for a system in which multiple RF power signals are applied to a load is by varying the multiple RF signals associated by amplitude, frequency, and phase. The relative amplitudes, frequencies, and phases of the multiple RF power signals may also be associated by coefficients related to a Fourier series. The frequencies between the multiple RF power signals may be locked, and the relative phase between the multiple RF signals may also be locked. Examples of such systems can be found by reference to U.S. Patent No. 7,602,127, U.S. Patent No. 8,110,991, and U.S. Patent No. 8,395,322, all of which are assigned to the assignee of the present application and incorporated herein by reference.

[0036] Time-varying or non-linear loads can exist in various applications. In one application, a plasma processing system may also include components for plasma generation and control. One such component is a non-linear load implemented as a process chamber, such as a plasma chamber or reactor. As an example, a typical plasma chamber or reactor utilized in a plasma processing system, such as for thin film manufacturing, can utilize a dual power system. One generator (source) controls plasma generation, and the generator (bias) controls ion energy. Examples of dual power systems include the systems described in U.S. Patent No. 7,602,127, U.S. Patent No. 8,110,991, and U.S. Patent No. 8,395,322, referenced above. The dual power systems described in the patents referenced above require a closed-loop control system to adapt the power operation for the purpose of controlling the ion density and its corresponding ion energy distribution function (IEDF).

[0037] There are multiple techniques for controlling a process chamber such that it can be used to generate 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 plasma generation. For an RF-driven plasma source, the periodic waveforms that affect plasma sheath dynamics, and the corresponding energies, are generally known and are controlled by the phase interactions associated with the frequency of the periodic waveforms. Another technique in an RF power delivery system involves dual frequency control. That is, two RF frequency sources operating at different frequencies are used to supply power to the plasma chamber to provide substantially independent control of the ion density and the electron density.

[0038] Other techniques utilize a broadband RF power source to drive the plasma chamber. The broadband technique presents certain challenges. One challenge is coupling the power to the electrodes. A second challenge is that the transfer function of the generated waveform with respect to the actual sheath voltage for the desired IEDF must be formulated over a wide process space to support the interaction with the material surface. In one responsive technique in an inductively coupled plasma system, controlling the 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 IEDF to provide etch rate control. By using the control of the source and bias electrodes, the etch rate is controlled through the density and energy of the ions.

[0039] As integrated circuits and device manufacturing continue to evolve, the power requirements for controlling the processes for manufacturing also continue to evolve. For example, in the manufacture of memory devices, the requirements regarding bias power have been continuously increasing. The increased power generates higher energy ions for faster surface interactions, thereby increasing the etching rate and directionality of the ions. In an RF system, the increased bias current sometimes involves an increase in the number of bias power sources coupled to the plasma sheath created in the plasma chamber, along with a requirement for a lower bias frequency. The power increase at lower bias frequencies, and the increased number of bias power sources result in intermodulation distortion (IMD) radiation from sheath modulation. The IMD radiation can significantly reduce the power delivered by the source where plasma generation occurs. U.S. Patent No. 10,821,542, issued on November 3, 2020, titled Pulse Synchronization by Monitoring Power in Another Frequency Band, which is assigned to the assignee of the present application and incorporated herein by reference, describes a method of pulse synchronization by monitoring power in another frequency band. In the referenced U.S. patent application, the pulsing of a second RF generator is controlled in accordance with detecting the pulsing of a first RF generator in the second RF generator, thereby synchronizing the pulsing between the two RF generators.

[0040] In a plasma processing system, plasma uniformity control is one important consideration to meet certain production yield requirements. A conductor etcher (or poly etcher) is a type of ICP that uses selective dry etching on a wafer pattern. Conventional ICP etchers use multiple antenna coils separated from the vacuum space by a window, which is a dielectric material that enables RF power penetration into the plasma chamber or reactor to ignite and maintain the plasma. An antenna coil is an electrode structure that induces external electrical energy into the plasma generation space. Although antenna coils can take various shapes and definitions depending on their structure, typical ICP systems have evolved from a single antenna to dual or multiple antenna coil shapes. Such shapes can be used, for example, in the processing of 300 mm (about 12 inches) wafers.

[0041] Typical electrical energy supply and delivery methods for structures using two or more antenna coils are powered from one electrical energy supply source or power source, such as an RF generator operating in the frequency range of kilohertz (kHz) to megahertz (MHz) in the semiconductor device industry, although other frequency ranges are also considered. The frequency signal is typically applied to the plasma chamber or reactor through a matching network for matching the load impedance and a power splitter for distributing power to two or more antenna coils. The magnetic field generated by the current flowing through each antenna coil penetrates the plasma discharge space, and the induced electric field ionizes the space particles, resulting in the generation of plasma. The resulting plasma forms a local discharge space depending on the strength of the magnetic field and the subsequent strength of the induced electric field, which typically concentrates within the range of several device lengths to several tens of device lengths. Plasma-induced radicals and ionized particles can diffuse throughout the discharge space.

[0042] The power splitter distributes appropriate power to each antenna. The power splitter is typically a combination in a series-parallel configuration of variable capacitors and inductors. These electrical circuits control the current by adjusting the impedance of each antenna by varying additional variable capacitors and inductors inserted into the power splitter circuit, and thus is also called a current splitter circuit. Therefore, by adjusting the current splitter, the ratio of the currents flowing through each antenna is controlled, and the distribution of the generated plasma is controlled. In various configurations, it is possible to split the voltage instead of the current.

[0043] In a conventional current splitting circuit, it is impossible for the plasma distribution to be linearly controlled by the ratio of the currents flowing through each antenna. The plasma is a dielectric for the bulk plasma, and the conductive medium for the plasma sheath is in contact with the boundary, so the antennas are not separated by independent loads, and thus each antenna is coupled to each other and through the generated plasma. In addition, the plasma coupling also directly affects the drive electrical circuit including the current splitter. Therefore, the current ratio is not linearly represented. In other words, when additional current needs to be applied to any of the antennas, the current ratio is non-linear. As a result, controlling the current ratio by changing the actuator in a region with a steep gradient is inaccurate and results in a large plasma dispersion between chambers. Even if the current ratio is controlled and set via the current splitter, slight variations in the plasma indicate differences between etching devices, which lead to differences in the quality of the semiconductor devices being manufactured and ultimately affect the production yield.

[0044] Conventional techniques for matching networks for multi-coil ICP chambers do not address the non-linear interaction between RF currents. The first conventional technique uses a capacitor connected in series to two branched antenna coils to control the current to each antenna, and the second conventional technique uses a capacitor configured in parallel to two branched antenna coils to control the current to each antenna.

[0045] The first method uses a variable capacitor in a branch circuit in series with the chamber impedance to adjust the current ratio in an ICP system. A pair of inductances reduces the magnitude of the current. However, the coupling through the RF coil or the plasma is not considered. Further, this first method does not address the non-linear current ratio of the RF current. A second conventional method for current ratio control uses one or more variable capacitors connected in parallel with the RF coil. This second method does not address the non-linear characteristics of the current ratio.

[0046] In the conventional ICP systems described above, the mutual inductance between two RF coils and / or the underlying characteristics of the ICP chamber or reactor, interact with the current in the RF coil. The interaction between the currents results in a non-linear current ratio. The non-linear current ratio between the RF currents complicates the plasma density control implemented by the control loop of the current ratio controller.

[0047] Plasma processing systems that do not account for the non-linear interaction of RF currents inhibit consistent and smooth current ratio control, increase the response time in the current ratio control loop, and increase the overall impedance matching time of the system. It is desirable to reduce the impedance matching time in the plasma processing system (e.g., to less than 500 microseconds using an electronically variable capacitor). An improved response time of the current ratio control loop facilitates reducing the impedance matching time of the ICP system.

[0048] This disclosure describes the use of a demagnetizing coil to increase the linearity of the current ratio between RF coils, which helps to enhance the controllability of the plasma density or plasma uniformity of a plasma processing system.

[0049] FIG. 1 shows a representation of an inductively coupled plasma (ICP) system 110. The ICP system 110 includes a non-linear load such as a reactor, plasma reactor, or plasma chamber 112, which is interchangeably referred to herein for generating plasma 114. Power in the form of voltage or current is applied to the plasma chamber 112 via a pair of coils including a coil assembly including an inner coil 116 and an outer coil 118 in various embodiments. Power is applied to the inner coil 116 via an RF generator or power supply 120, and power is applied to the outer coil 118 via an RF generator or power supply 122. Coils 116 and 118 are attached to a dielectric window 124 that helps couple power to the plasma chamber 112. A substrate 126 is disposed within the plasma chamber 112 and typically forms a workpiece that is the subject of plasma operation. An RF generator, power supply, or power source 128 (these terms may be used interchangeably herein) applies power to the plasma chamber 112 via the substrate 126. In various configurations, the power supplies 120, 122 provide a power supply voltage or current to ignite or generate the plasma 114 or to control the plasma density. Also, in various configurations, the power supply 128 provides a bias voltage or current that modulates ions to control the ion energy or ion density of the plasma 114. In various embodiments, the power supplies 120, 122 are locked to operate at the same frequency, voltage, and current with a fixed or varying relative phase. In various other embodiments, the power supplies 120, 122 may operate at different frequencies, voltages, currents, and relative phases.

[0050] FIG. 2 shows an RF generator or a power supply system 210. The power supply system 210 includes a pair of radio frequency (RF) generators or power sources 212a, 212b, matching networks 218a, 218b, and a load 232 such as a non-linear load that can be a plasma chamber, a process chamber, etc. In various embodiments, the RF generator 212a is referred to as a source RF generator or power supply, and the matching network 218a is referred to as a source matching network. Also, in various embodiments, the RF generator 212b is referred to as a bias RF generator or power supply, and the matching network 218b is referred to as a bias matching network. It will be understood that the components can be referred to individually or collectively using reference numbers without subscripts or prime symbols.

[0051] In various embodiments, source RF generator 212a receives control signal 230 from matching network 218b, generator 212b, or receives control signal 230' from bias RF generator 212b. As will be described in more detail, control signal 230 or 230' represents an input signal to source RF generator 212a that indicates one or more operating characteristics or parameters of bias RF generator 212b. In various embodiments, synchronous bias detector 234 senses the RF signal output from matching network 218b to load 232 and outputs synchronous or trigger signal 230 to source RF generator 212a. In various embodiments, instead of trigger signal 230, synchronous or trigger signal 230' may be output from bias RF generator 212b to source RF generator 212a. The difference between trigger or synchronous signals 230, 230' may result from the effect of matching network 218b, which can adjust the phase between the input signal to the matching network and the output signal from the matching network. Signals 230, 230' include information regarding the operation of bias RF generator 212b that enables predictive responsiveness to periodic variations in the impedance of the plasma chamber or load 232 caused by bias RF generator 212b in various embodiments. In the absence of control signal 230 or 230', RF generators 212a, 212b operate autonomously.

[0052] The RF generators 212a, 212b each include respective RF power supplies or amplifiers 214a, 214b, RF sensors 216a, 216b, and processors, controllers, or control modules 220a, 220b. The RF power supplies 214a, 214b generate respective RF power signals 222a, 222b that are output to respective sensors 216a, 216b. The sensors 216a, 216b receive the outputs of the RF power supplies 214a, 214b and generate respective RF power signals f1, f2. The sensors 216a, 216b also output signals that vary according to various parameters sensed from the load 232. The sensors 216a, 216b are shown within respective RF generators 212a, 212b, but the RF sensors 216a, 216b can be located external to the RF generators 212a, 212b. Such external sensing can occur at the output of the RF generator, at the input of an impedance matching device disposed between the RF generator and the load, or between the output of the impedance matching device (including within the impedance matching device) and the load.

[0053] The sensors 216a, 216b detect various operating parameters and output signals X and Y. The sensors 216a, 216b may include voltage sensors, current sensors, and / or directional coupler sensors. The sensors 216a, 216b can detect (i) voltage V and current I, and / or (ii) forward power P output from respective power amplifiers 214a, 214b and / or RF generators 212a, 212b FWD , and reverse or reflected power P received from respective load 232 connected to respective matching networks 218a, 218b or respective sensors 216a, 216b. The voltage V, current I, forward power P REV , and reverse power P FWD . REVmay be the scaled, filtered, or scaled and filtered versions of the actual voltage, current, forward power, and reverse power associated with each power supply 214a, 214b. Sensors 216a, 216b can be analog sensors, digital sensors, or a combination thereof. In a digital implementation, sensors 216a, 216b may include an analog-to-digital (A / D) converter and a signal sampling component having a corresponding sampling rate. Signals X and Y can represent either voltage V and current I, or forward (or source) power P FWD and reverse (or reflected) power P REV .

[0054] Sensors 216a, 216b generate sensor signals X, Y that are received by respective controllers or power control modules 220a, 220b. Power control modules 220a, 220b process the respective X, Y signals 224a, 226a, and 224b, 226b and generate one or more feedforward or feedback control signals 228a, 228b to respective power supplies 214a, 214b. Power supplies 214a, 214b adjust RF power signals 222a, 222b based on the received one or more feedback or feedforward control signals. In various embodiments, power control modules 220a, 220b may each control matching networks 218a, 218b via respective control signals 221a, 221b. Power control modules 220a, 220b may include any of at least a proportional-integral-derivative (PID) controller or subset thereof, and / or a direct digital synthesis (DDS) component, and / or various components described below in connection with the modules.

[0055] In various embodiments, power control modules 220a, 220b are PID controllers or subsets thereof and may include functions, processes, processors, or submodules. Control signals 228a, 228b may be drive signals and may include a DC offset or rail voltage, voltage or current magnitude, frequency, and phase components. In various embodiments, feedback control signals 228a, 228b can be used as inputs to one or more control loops. In various embodiments, the plurality of control loops can include proportional integral derivative (PID) control loops for RF drive and rail voltage. In various embodiments, control signals 228a, 228b can be used in a multiple input multiple output (MIMO) control scheme. An example of an MIMO control scheme can be found by reference to U.S. Patent No. 10,546,724, issued January 28, 2020, titled Pulsed Bidirectional Radio Frequency Source / Load, assigned to the assignee of the present application, and incorporated herein by reference. In other embodiments, signals 228a, 228b can provide feedforward control as described in U.S. Patent No. 10,049,857, assigned to the assignee of the present application, and incorporated herein by reference.

[0056] In various embodiments, the power supply system 210 can include a controller 220'. The controller 220' may be disposed external to either or both of the RF generators 212a, 212b and may be referred to as an external or common controller 220'. In various embodiments, the controller 220' may implement one or more of the functions, processes, or algorithms described herein with respect to one or both of the controllers 220a, 220b. Thus, the controller 220' communicates with each of the RF generators 212a, 212b via a respective pair of links 236, 238 that enable the exchange of data and control signals as needed between the controller 220' and the RF generators 212a, 212b. For various embodiments, the controllers 220a, 220b, 220' can provide analysis and control in a distributed and cooperative manner with the RF generators 212a, 212b. In various other embodiments, the controller 220' can provide control of the RF generators 212a, 212b, eliminating the need for the respective local controllers 220a, 220b.

[0057] In various embodiments, the RF power supply 214a, the sensor 216a, the controller 220a, and the matching network 218a may be referred to as a source RF power supply 214a, a source sensor 216a, a source controller 220a, and a source matching network 218a. Similarly, in various embodiments, the RF power supply 214b, the sensor 216b, the controller 220b, and the matching network 218b may be referred to as a bias RF power supply 214b, a bias sensor 216b, a bias controller 220b, and a bias matching network 218b. In various embodiments, as described above, the source term refers to an RF generator that generates plasma, and the bias term refers to an RF generator that adjusts the plasma ion energy distribution function (IEDF). In various embodiments, the source RF power supply and the bias RF power supply operate at different frequencies. In various embodiments, the source RF power supply operates at a higher frequency than the bias RF power supply. In various other embodiments, the source RF power supply and the bias RF power supply operate at the same frequency or substantially the same frequency.

[0058] According to various embodiments, source RF generator 212a and bias RF generator 212b include a plurality of ports for communicating with the outside. Source RF generator 212a includes a pulse synchronization output port 240, a digital communication port 242, and an RF output port 244. Bias RF generator 212b includes an RF input port 248, a digital communication port 250, and a pulse synchronization input port 252. Pulse synchronization output port 240 outputs a pulse synchronization signal 256 to pulse synchronization input port 252 of bias RF generator 212b. Digital communication port 242 of source RF generator 212a and digital communication port 250 of bias RF generator 212b communicate via a digital communication link 257. RF output port 244 generates an RF control signal 258 that is input to RF input port 248. In various embodiments, RF control signal 258 is substantially the same as the RF control signal that controls source RF generator 212a. In various other embodiments, RF control signal 258 is the same as the RF control signal that controls source RF generator 212a, but is phase shifted within source RF generator 212a according to the required phase shift generated by bias RF generator 212b. Thus, in various embodiments, source RF generator 212a and bias RF generator 212b are driven by substantially the same RF control signal or by substantially the same RF control signal phase shifted by a predetermined amount.

[0059] In various configurations, one or both of the matching networks 218a, 218b can be configured as a combination of a matching network and a current divider, as shown for matching network / current divider 218a. The matching network / current divider 218a performs at least two functions. The first function is conventional impedance matching. The second function is to divide an input RF power signal f1 into one or more outputs that are applied to respective coil ICP coils, such as coils 116, 118 of FIG. 1, of load 232. Dividing the input RF output signal f1 into one or more outputs enables changing the power applied to each of coils 116, 118. In various configurations, the RF output power signal can be divided between coils 116, 118 of FIG. 1 using a ratioing technique. The power is divided to provide a desired ratio between the power applied to one of coils 116, 118 and the power applied to the other of coils 116, 118. In various configurations, throughout this specification, the matching network and current divider of matching network / current divider 218a can be an integrated unit, can be separate units, or can be distributed across one or more components.

[0060] As shown in FIG. 2, a pair of RF power signals output by matching network / current divider 218a are input to demagnetization circuit 260. As will be described in more detail below, demagnetization circuit 260 includes an inductive component that receives the RF power signal output from matching network / current divider 218a that generates mutual coupling. The mutual coupling is configured to substantially cancel the mutual coupling in coils 116, 118, as shown in FIG. 1. It will be appreciated that the configuration of matching network / current divider 218a can be implemented in one or both of matching networks 218a, 218b.

[0061] As will be described in detail in the following figures, the present disclosure discloses a demagnetizing coil in series with an ICP chamber to enhance the linearity of the current ratio of an RF coil and the controllability of plasma density or plasma uniformity in a plasma processing system. FIG. 3 shows a block diagram of a plasma system 310 including a demagnetizing circuit according to the present disclosure. An RF generator 312 generates an RF output applied to an impedance matching network / current divider 318. The impedance matching network / current divider 318 operates in the same manner as described above with respect to FIG. 2. The impedance matching network / current divider 318 generates a pair of outputs or split signals to a demagnetizing circuit 360. The demagnetizing circuit 360 includes a demagnetizing coil for generating an induced magnetic field that opposes the magnetic fields induced in the inner coil and the outer coil in an ICP configuration. The demagnetizing circuit 360 generates a pair of RF power signals, one of the pair being applied to one of a pair of terminals 362a, 362b of the inner coil 362 and the other of the pair being applied to one of a pair of terminals 364a, 364b of the outer coil 364. The impedance at the output of the RF generator 312 is represented by an equivalent impedance Z eq and represents the impedance resulting from the equivalent impedance of the components including the impedance matching network / current divider 318, the demagnetizing circuit 360, and the plasma chamber or load 332.

[0062] The plasma chamber or load 332 is energized by RF signals applied to each of the inner coil 362 and the outer coil 364. The electrode 334 may be grounded or supplied with power via a second RF generator (not shown in FIG. 3) that applies power via an ICP or CCP configuration. Application of power to the plasma chamber or load 332 generates a plasma 336 inside the plasma chamber or load 332. The plasma 336 enables the application of various manufacturing and fabrication processes.

[0063] FIG. 4 shows a circuit diagram of a portion 410 of a power delivery system arranged in accordance with the present disclosure. The RF power supply or power source 412 outputs an RF signal to an equivalent impedance Z including a matching network / current divider 418, a demagnetization circuit 460, and a plasma chamber or load 432. eq The matching network portion of the matching network / current divider 418 includes an inductor L8 in series with a variable capacitor V C1 and both are in parallel with an inductor L5 in series with a variable capacitor V C2 The inductor L8 and the variable capacitor V C1 form the shunt leg of the matching network, and the inductor L5 and the variable capacitor V C2 form the series leg of the matching network. Current division is performed by a circuit formed by an inductor L7 in parallel with a capacitor C4 and an inductor L6. The variable capacitor V C3 provides a shunt to ground and connects between the capacitor C4 and the inductor L6. Changing the capacitance of V C3 changes the power ratio between the RF power applied to the inner coil and the RF power applied to the outer coil.

[0064] The matching network / current divider 418 is shown using an L-type matching circuit. Other matching circuits including a T-type or π-type matching circuit or a combination thereof that control the total impedance Z eq seen by the RF generator and the current ratio between the RF coil L1 and the RF coil L2 may also be used. The variable capacitors V C1 V C2is varied to provide an impedance for reducing the reflected power to the RF power supply 412, thereby increasing the forward power applied to the plasma chamber or load 432. The power ratio between the inner coil L1 and the outer coil L2 for adjusting the plasma density in the inner and outer regions of the plasma chamber or load 432 is controlled by the total forward power sent from the RF power supply 412 and the current ratio between the inner coil L1 and the outer coil L2. In a non-limiting example, the target powers of the inner coil L1 and the outer coil L2 are 1000 W and 500 W, respectively. In such a configuration, the system controller controls 1500 W of total forward power from the RF power supply 412 to the plasma chamber or load 432, and the current ratio of the inner coil L1 and the outer coil L2 is controlled to 2:1. As described above, the current division circuit of the matching network uses the shunt variable capacitor V C3 but is not limited to other configurations for controlling the current ratio of the RF coils.

[0065] The matching circuit / current divider 418 outputs a pair of RF power signals applied to the respective inner coil or inductor L3 and outer coil or inductor L4 of the demagnetization circuit 460. Thus, the demagnetization circuit 460 outputs a plurality of signals. As further described herein, the plurality can be two, three, or four or more divided signals. The inner coil L3 and the outer coil L4 output RF power signals to the respective inner antenna, inductor, or coil L1 and outer antenna, inductor, or coil L2 of the plasma chamber or load 432. The inner coil L1 and the outer coil L2 are connected to ground via respective impedances Z in and Z out representing the impedance in the plasma chamber or load 432.

[0066] As shown in FIG. 4, the inner coil L3 and the outer coil L4 are represented as inductors formed by the coils. However, the inner coil L3 and the outer coil L4, in various configurations, generate a mutual inductance M that substantially cancels or offsets the mutual inductance generated by the inner coil or inductor L1 and the outer coil or inductor L2 within the ICP chamber or the load 432. 34 represents inductances that interact to generate. Thus, L3 and L4 may refer to inductances, and such inductances may be induced rather than generated through an inductive coil.

[0067] The equivalent circuit of the ICP chamber or the load 432 includes the self-inductances L1 and L2 of the RF coils and the mutual inductance M 12 of the RF coils, and the two equivalent impedances Z In and Z Out of the chamber. The inner coil L1 and the outer coil L2 are connected to ground through their respective impedances Z in and Z out The mutual inductance M 12 represents the coupling impedance or mutual inductance generated by the two RF coils and / or the chamber plasma.

[0068] The demagnetization circuit 460 includes demagnetizing coils L3 and L4 in series with the plasma chamber or the load 432 connected to the ICP. The current ratio CR between the inner RF coil and the outer RF coil is given by Equation (1),

Number

Number

[0069] From the above, it can be seen that the current ratio becomes linear under one of the following conditions.

Number

[0070] In the circuit of FIG. 4, the demagnetization circuit 460 provides the linearity of the current ratio between RF coils such as the inner coil L1 and the outer coil L2 for the ratio of Equation (1)

Number

Number

[0071] In the mutual inductance compensation technique, the self-inductances L3 and L4 of the degaussing circuit 460 can have the same or different self-inductances as the coils L1 and L2. The mutual inductance M 34 of the degaussing coils L3 and L4 must be substantially equal to the magnitude of the mutual inductance M 12 of the coils L1 and L2, which represents the complex coupling between the RF coils and / or between the plasmas in the chamber. The direction between the mutual inductance M 12 and the mutual inductance M 34 is opposite. The interaction between the two inner and outer currents represented by the mutual inductance M 12 of the chamber through the coils L1 and L2 is substantially canceled by the mutual inductance M 34 of the degaussing coils L3 and L4. The substantial cancellation makes the current ratio of the RF coils L1 and L2 substantially linear. The inductors L6 and L7 in the matching network / current divider 418 of FIG. 6 can be integrated with the inductors L3 and L4 of the degaussing circuit 460 to reduce the size, cost, or assembly of the matching network / current divider 418.

[0072] In the mutual inductance suppression technique, the mutual inductance M 34 of the degaussing inner coil L3 and outer coil L4 is zero (M34 is zero or non - zero (M 34 ≠0), which is not a problem. The self - inductance of the inner demagnetizing coil L3 and the outer demagnetizing coil L4, or the total self - inductance of the inner path (L3 and L7) and the outer path (L4 and L6), is designed to be much larger than the total mutual inductance (M 12 +M 34 ). In such a configuration, the non - linear interaction between the RF current coils has little effect, and the current ratio becomes more linear.

[0073] Figure 5 shows a plot of the current ratio versus capacitance between two RF coils of an ICP chamber with or without a demagnetizing coil. The x - axis represents the value of the variable capacitor V C3 with respect to the power ratio of the RF power applied to the inner coil L1 and the outer coil L2. Plot 510 shows the current ratio of a conventional system without using the demagnetizing circuit of the present disclosure. As can be seen, plot 510 shows a non - linear configuration.

[0074] Plot 512 shows the current ratio using the mutual inductance suppression method. For plot 512, the mutual inductance M 34 is zero, while the mutual inductance M 12 is non - zero. The total self - inductance Z Si of the inner and outer circuits is about five times larger than the mutual inductance Z M , which represents the complex coupling of the ICP chamber. Plot 514 shows the current ratio using the mutual inductance compensation method. In the mutual inductance compensation method, the mutual inductance M 34 of the inner demagnetizing coil L3 and the outer demagnetizing coil L4 has the same amplitude as the mutual inductance M 12 of the inner coil L1 and the outer coil L2 for supplying power to the plasma chamber or load 432 in the ICP configuration, but has the opposite polarity. Both the mutual inductance compensation method shown in plot 514 and the mutual inductance suppression method shown in plot 512 can improve the linearity of the current ratio of the RF coils of the ICP chamber.

[0075] FIG. 6 shows a circuit diagram of a part 610 of a power delivery system arranged according to the present disclosure. The configuration of FIG. 6 is the same as that of FIG. 4, except that the demagnetization circuit 660 is arranged on the opposite side of the impedance matching network / current divider 618 from the plasma chamber or load 632. The RF power supply 612 outputs an RF signal to an equivalent impedance Z including the matching network / current divider 618, the demagnetization circuit 660, and the plasma chamber or load 632. The components of FIG. 6 operate in the same manner as the components of FIG. 4, and the demagnetization circuit 660 and the plasma chamber or load 632 are arranged at opposite positions within the circuit. The circuits of FIGS. 4 and 6 operate similarly in that they enable a linear current ratio between the RF power applied to the inner coil and the RF power applied to the outer coil. eq to. The components of FIG. 6 operate in the same manner as the components of FIG. 4, and the demagnetization circuit 660 and the plasma chamber or load 632 are arranged at opposite positions within the circuit. The circuits of FIGS. 4 and 6 operate similarly in that they enable a linear current ratio between the RF power applied to the inner coil and the RF power applied to the outer coil.

[0076] FIG. 7 shows a circuit diagram of a part 610 of a power delivery system arranged according to the present disclosure. The configuration of FIG. 7 is the same as that of FIG. 4 or FIG. 6, except that three coils provide an ICP connection between the impedance matching network / current divider 718 generated using the ICP connection by the three coils and the plasma chamber or load 732. The three ICP coils include an inner coil L3, an intermediate coil L2, and an outer coil L2'. The demagnetization circuit 760 includes three coils corresponding to the inner coil L1, the intermediate coil L2, and the outer coil L2', respectively, including an inner coil L3, an intermediate coil L4, and an outer coil L4'. The demagnetization circuit 760 includes three mutual inductances M 12 , M 22 , and M 12 ' to compensate for the three mutual inductances M 34 , M 44 , and M 34 ' for. In such a configuration, Equation (1) can be adjusted to account for the additional terms introduced by the addition of the third coil.

[0077] Similar to FIG. 6, in various configurations, the demagnetization circuit 760 of FIG. 7 can be disposed on the opposite side of the impedance matching network / current divider 718 from the plasma chamber or load 732. That is, the plasma chamber or load 732 is disposed between the matching network / current divider 718 and the demagnetization circuit 760. In any configuration of the demagnetization circuit 760 disposed in front of the plasma chamber or load, or the plasma chamber or load 732 disposed in front of the demagnetization circuit 730, the circuit of FIG. 7 operates to provide a linear current ratio between the RF power applied to the three coils or inductances, the inner coil or inductance L1, the intermediate coil or inductance L2, and the outer coil or inductance L2'.

[0078] FIGS. 8 and 9 show various demagnetization circuit configurations arranged in accordance with the present disclosure. In FIG. 8, the demagnetization circuit 810 shows a bus bar including connectors arranged to correspond to the inner coil L3 and the outer coil L4, respectively. Power is provided to the inner demagnetization coil L3 via the terminal or connector 812 and flows through the conductor or electrical conductor 814 to the terminal or connector 818. The terminal or connector 818 is connected to the ICP outer coil L1 of a plasma chamber or load such as the plasma chamber or load 432, 632, or 732. Similarly, power is provided to the demagnetization outer coil L4 via the terminal or connector 820 and flows through the electrical conductor 822 to the terminal or connector 824. The terminal or connector 824 is connected to the ICP outer coil L2 of a plasma chamber or load such as the plasma chamber or load 432, 632, or 732.

[0079] The current or power flowing through the electrical conductor 814 generates a magnetic flux 830, and the same current flowing through the inner coil L1 generates a magnetic flux 832. The magnetic fluxes 830 and 832 are regarded as mutual magnetic fluxes and have opposite polarities to provide a demagnetizing effect. Similarly, the current or power flowing through the electrical conductor 822 generates a magnetic flux 834, and the same current flowing through the outer coil L2 generates a magnetic flux 836. The magnetic fluxes 834 and 836 are regarded as mutual magnetic fluxes and have opposite polarities to provide a demagnetizing effect. By appropriate selection of the lengths L of the electrical conductors 814, 822, and the gap G between the electrical conductor 814 and the electrical conductor 822, the respective magnetic fluxes 830, 834 can be adjusted to substantially cancel out the respective magnetic fluxes 832, 836. Therefore, the demagnetizing circuit 810 can be provided by selectively configuring the dimensions of the bus bar shown in FIG. 8.

[0080] In FIG. 9, the demagnetizing circuit 910 shows a bus bar formed to include an inner demagnetizing coil L3 and an outer demagnetizing coil L4, respectively. Power is provided to the inner demagnetizing coil L3 via a terminal or connector 912 and flows through the demagnetizing inner coil 914 (L3) to the terminal or connector 918. The terminal or connector 918 is connected to the ICP outer coil L1 of a plasma chamber or load such as the plasma chambers or loads 432, 632, or 732. Similarly, power is provided to the outer demagnetizing coil L4 via a terminal or connector 920 and flows through the demagnetizing outer coil 922 (L4) to the terminal or connector 924. The terminal or connector 924 is connected to the ICP outer coil L2 of a plasma chamber or load such as the plasma chambers or loads 432, 632, or 732.

[0081] The current or power flowing through the demagnetization inner coil 914 generates a magnetic flux 930, and the same current flowing through the inner coil L1 generates a magnetic flux (not shown). The magnetic flux of the inner coil L1 and the magnetic flux 930 are regarded as mutual magnetic fluxes and have opposite polarities to provide a demagnetization effect. Similarly, the current or power flowing through the demagnetization outer coil 922 generates a magnetic flux 934, and the same current flowing through the outer coil L2 generates a magnetic flux (not shown). The magnetic flux of the outer coil L2 and the magnetic flux 934 are regarded as mutual magnetic fluxes and have opposite polarities to provide a demagnetization effect.

[0082] The disclosure of the subject matter may, but need not, provide one or more of the following advantages. The demagnetization coil compensates for or suppresses the influence of the mutual inductance between the RF coils of the plasma processing system. By using the disclosed demagnetization coil, the non-linear current ratio between the inner RF ICP coil and the outer RF ICP coil becomes linear, which shortens the response time, improves the accuracy, and improves the smoothness of the current ratio control loop. During operation, the matching control loop is completed after the current ratio control loop. Therefore, the improvement of the current ratio control loop shortens the impedance matching time of the matching network. The positions of the demagnetization coil and the impedance matching network are flexible. The present invention includes, but is not limited to, two RF coils or multiple ICP coils or antennas for a plasma chamber. The demagnetization coil includes, but is not limited to, a general RF coil, a bus bar, a microstrip, or a stripline. Various advantages include the improvement of the efficiency and quality of the etching process, as well as the reduction of the maintenance and repair time.

[0083] Customers of plasma etching can benefit from using a degaussing coil that linearly improves the current ratio between the RF coils of an ICP chamber. However, the degaussing coil described herein is not necessary but can provide other benefits. The ICP chamber used for etching includes a plurality of RF coils and requires controlling the current ratio between those RF coils to improve the controllability of plasma uniformity. Such a configuration includes process requirements for sufficient impedance matching time and control loop accuracy. The non-linear relationship between the RF coils and / or plasma of the ICP chamber limits the response time, accuracy, and matching speed of the system. Furthermore, current ratio control in a system with a non-linear slope is inaccurate and results in a large plasma dispersion between chambers. The proposed degaussing coil disclosed herein can improve the linearity of the current ratio between the RF coils, which helps improve the speed and accuracy of the control loop of the ICP chamber system.

[0084] The foregoing description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or its use. The broad teachings of the present disclosure can be implemented in a variety of forms. Accordingly, while this disclosure includes specific examples, other modifications will become apparent upon consideration of the drawings, the specification, and the following claims, and the true scope of the present disclosure should not be so limited. In the specification and claims, one or more steps within a method may be performed in a different order (or simultaneously) without changing the principles of the present disclosure. Similarly, one or more instructions stored within a non-transitory computer-readable medium may be executed in a different order (or simultaneously) without changing the principles of the present disclosure. Unless otherwise indicated, the numbering or other labeling of instructions or method steps is for convenient reference only and does not indicate a fixed order.

[0085] Furthermore, while each of the embodiments has been described above as having certain features, any one or more of these features described with respect to any embodiment of the present disclosure may be implemented in and / or combined with any of the features of other embodiments even if their combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with each other remain within the scope of the present disclosure.

[0086] Spatial and functional relationships between elements (e.g., between modules, between circuit elements, between semiconductor layers, etc.) are described using various terms including "connected", "engaged", "coupled", "adjacent", "in contact with", "on top of", "above", "below", and "disposed". Unless explicitly described as "direct", when a relationship between a first element and a second element is described in the above disclosure, the relationship can be a direct relationship in which no other intervening elements exist between the first element and the second element, but can also be an indirect relationship in which one or more intervening elements exist (spatially or functionally) between the first element and the second element.

[0087] The phrase "at least one of A, B, and C" should be interpreted to mean the logic (A OR B OR C) using non-exclusive logical OR, and should not be interpreted to mean "at least one A, at least one B, and at least one C". The term "set" does not necessarily exclude the empty set; in other words, in some situations, a "set" may have zero elements. The term "non-empty" set can be used to indicate the exclusion of the empty set; in other words, a non-empty set always has one or more elements. The term "subset" does not necessarily require a proper subset; in other words, a "subset" of a first set may have the same extent (may be equal) as the first set. Further, the term "subset" does not necessarily exclude the empty set; in some situations, a "subset" may have zero elements.

[0088] In the figure, the direction of the arrow indicated by the arrowhead generally indicates the flow of information (such as data or instructions) important for the illustration. For example, if element A and element B exchange various information, and the information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This one-way arrow does not mean that no other information is transmitted from element B to element A. Further, for the information transmitted from element A to element B, element B may transmit a request or an acknowledgment of receipt for that information to element A.

[0089] In this application, which includes the following definitions, the term "module" can be replaced with the term "controller" or the term "circuit". In this application, the term "controller" can be replaced with the term "module". The term "module" refers to, or is part of, or may include, one or more of the following: application specific integrated circuits (ASICs), digital, analog, or analog / digital mixed discrete circuits, digital, analog, or analog / digital mixed integrated circuits, combinatorial logic circuits, field programmable gate arrays (FPGAs), processor hardware that executes code (shared, dedicated, or grouped), memory hardware that stores code executed by processor hardware (shared, dedicated, or grouped), other suitable hardware components that provide the described functionality, or combinations of some or all of the above, such as in a system-on-chip.

[0090] A module may include one or more interface circuits. In some examples, the interface circuit may implement a wired or wireless interface to connect to a local area network (LAN) or a wireless personal area network (WPAN). Examples of LANs are the Institute of Electrical and Electronics Engineers (IEEE) Standard 802.11-2020 (also known as the WIFI wireless networking standard), and the IEEE Standard 802.3-2018 (also known as the Ethernet wired networking standard). Examples of WPANs are the IEEE Standard 802.15.4 (including the ZIGBEE (registered trademark) standard from the ZigBee (registered trademark) Alliance), and the BLUETOOTH (registered trademark) wireless networking standards (including core specification versions 3.0, 4.0, 4.1, 4.2, 5.0, and 5.1 from the Bluetooth (registered trademark) Special Interest Group (SIG)).

[0091] A module can communicate with other modules using an interface circuit. Although a module may be shown in this disclosure as communicating logically directly with other modules, in various implementations, a module can actually communicate via a communication system. The communication system includes physical and / or virtual networking devices such as hubs, switches, routers, and gateways. In some implementations, the communication system connects to or traverses a wide area network (WAN) such as the Internet. For example, the communication system may include multiple LANs connected to each other via the Internet or a point-to-point dedicated line using technologies including Multiprotocol Label Switching (MPLS) and Virtual Private Network (VPN).

[0092] In various implementations, the functions of a module may be distributed among multiple modules connected via a communication system. For example, multiple modules may implement the same function distributed by a load balancing system. In a further example, the functions of a module may be split between a server (also known as remote or cloud) module and a client (or user) module. For example, a client module may include a native application or a web application that runs on a client device and communicates with the server module over a network.

[0093] Some or all of the hardware functions of the module may be defined using a language for hardware description, such as IEEE Standard 1364-2005 (commonly referred to as "Verilog") and IEEE Standard 1076-2008 (commonly referred to as "VHDL"). The hardware description language may be used to manufacture and / or program the hardware circuit. In some implementations, some or all of the functions of the module may be defined by a language such as IEEE 1666-2005 (commonly referred to as "SystemC") that includes both the code described below and the hardware description.

[0094] The term code as used above may include software, firmware, and / or microcode and may refer to a program, routine, function, class, data structure, and / or object. Shared processor hardware includes a single microprocessor that executes some or all of the code from multiple modules. Group processor hardware includes a microprocessor that, in combination with additional microprocessors, executes some or all of the code from one or more modules. References to multiple microprocessors include multiple microprocessors on separate dies, multiple microprocessors on a single die, multiple cores of a single microprocessor, multiple threads of a single microprocessor, or combinations of the above.

[0095] Memory hardware can also store data either together with or separately from the code. Shared memory hardware includes a single memory device that stores some or all of the code from multiple modules. An example of shared memory hardware can be a level 1 cache on or near a microprocessor die that can store code from multiple modules. Another example of shared memory hardware can be persistent storage such as a solid state drive (SSD) that can store code from multiple modules. Group memory hardware includes a memory device that, in combination with other memory devices, stores some or all of the code from one or more modules. An example of group memory hardware can be a storage area network (SAN) that can store the code of a particular module across multiple physical devices. Another example of group memory hardware can be the random access memory of each of a set of servers that stores the code of a particular module in combination.

[0096] The term memory hardware is a subset of the term computer-readable medium. The term computer-readable medium as used herein does not include transient electrical or electromagnetic signals propagated via a medium (such as on a carrier wave), and thus the term computer-readable medium is considered tangible and non-transitory. Non-limiting examples of non-transitory computer-readable media are non-volatile memory devices (such as flash memory devices, erasable programmable read-only memory devices, or mask read-only memory devices), volatile memory devices (such as static random access memory devices or dynamic random access memory devices), magnetic storage media (such as analog or digital magnetic tape or hard disk drives), and optical storage media (such as CDs, DVDs, or Blu-ray (registered trademark) disks).

[0097] The apparatus and methods described in this application can be implemented partially or fully by a special-purpose computer created by configuring a general-purpose computer to perform one or more specific functions embodied in a computer program. Such apparatus and methods may be described as computerized apparatus and computerized methods. The functional blocks and flowchart elements described above function as software specifications that can be converted into a computer program by the routine work of a skilled technician or programmer.

[0098] A computer program includes processor-executable instructions stored on at least one non-transitory computer-readable medium. The computer program may also include, or be dependent on, stored data. The computer program may include a basic input / output system (BIOS) that interacts with the hardware of the special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, and the like.

[0099] A computer program can include (i) descriptive text to be parsed 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 computer, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, and the like. By way of example only, source code can be described using syntax from languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, JavaScript®, HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB®, SIMULINK®, and Python®.

Explanation of Signs

[0100] 110 Inductively coupled plasma (ICP) system, ICP system 112 Plasma chamber 114 Plasma 116 Inner coil, coil 118 Outer coil, coil 120 Power supply 122 Power supply 124 Dielectric window 126 Substrate 128 Power supply 210 Power supply system 212a RF generator, source RF generator, RF generator 212b RF generator, bias RF generator, RF generator 214a RF power supply or amplifier, RF power supply, power supply, source RF power supply 214b RF power supply or amplifier, RF power supply, power supply, bias RF power supply 216a RF sensor, sensor, source sensor 216b RF sensor, sensor, bias sensor 218a Matching network, source matching network, matching circuit 218b Matching network, bias matching network, matching circuit 220' Controller, external or common controller 220a Processor, controller, or control module, controller or power control module, power control module, local controller, source controller 220b Processor, controller, or control module, controller or power control module, power control module, local controller, bias controller 222a RF power signal 222b RF power signal 224a X signal 224b X signal 226a Y signal 226b Y signal 228a Feedforward and / or feedback control signal, control signal, feedback control signal, signal 228b Feedforward and / or feedback control signal, control signal, feedback control signal, signal 230 Control signal, synchronization or trigger signal, trigger signal, trigger or synchronization signal, signal 230' Control signal, synchronization or trigger signal, trigger or synchronization signal, signal 232 Load 234 Synchronous bias detector 236 Link 238 Link 240 Pulse synchronization output port 242 Digital communication port 244 RF output port 248 RF input port 250 Digital communication port 252 Pulse synchronization input port 256 Pulse synchronization signal 257 Digital communication link 258 RF control signal 260 Degaussing circuit 310 Plasma system 312 RF generator 318 Impedance matching network / current divider 332 Plasma chamber or load 334 Electrode 336 Plasma 360 Degaussing circuit 362 Inner coil 362a Terminal 362b Terminal 364 Outer coil 364a Terminal 364b Terminal 410 Part of power delivery system 412 RF power supply or power source, RF power source 418 Matching network / current divider 432 Plasma chamber or load, ICP chamber or load 460 Degaussing circuit 510 Plot 512 Plot 514 Plot 610 Part of power delivery system 612 RF power source 618 Impedance matching network / current divider, matching network / current divider 632 Plasma chamber or load 660 Degaussing circuit 718 Impedance matching network / current divider, matching network / current divider 730 Degaussing circuit 732 Plasma chamber or load 760 Degaussing circuit 810 Degaussing circuit 812 Terminal or connector 814 Conductor or electrical conductor, electrical conductor 818 Terminal or connector 820 Terminal or connector 822 Electrical conductor 824 Terminal or connector 830 Magnetic flux 832 Magnetic flux 834 Magnetic flux 836 Magnetic flux 910 Degaussing circuit 912 Terminal or connector 914 Inner degaussing coil 918 Terminal or connector 920 Terminal or connector 922 Outer degaussing coil 924 Terminal or connector 930 Magnetic flux 934 Magnetic flux

Claims

1. An RF power source configured to generate an output signal, A power splitter configured to receive the output signal and generate a plurality of split signals, A demagnetization circuit configured to receive the plurality of split signals, the demagnetization circuit being configured to include a plurality of inductances corresponding to the plurality of split signals, An RF generator comprising: The plurality of inductances are configured to reduce the influence of the mutual impedance of the ICP chamber in series with the plurality of inductances such that the ratio between the pair of the plurality of split signals changes substantially linearly as one of the pair of the plurality of split signals changes, RF generator.

2. The RF generator according to claim 1, wherein the plurality of inductances can be one of an inductance having a coil or an inductive inductance by conducting current through an electrical conductor.

3. The demagnetization circuit includes a plurality of outputs, the plurality of outputs corresponding to each one of a plurality of antennas of the ICP chamber, and a combined mutual inductance of the plurality of inductances corresponding to the plurality of split signals is substantially equal to a combined mutual inductance of the plurality of antennas of the ICP chamber. The RF generator according to claim 1.

4. The RF generator according to claim 1, further comprising a matching network configured to receive the output signal from the RF power source and provide the output signal to the power splitter, the matching network being configured to provide impedance matching with the RF power source.

5. The RF generator according to claim 1, wherein the demagnetization circuit is disposed between the power splitter and the load.

6. The RF generator according to claim 1, wherein the load is disposed between the demagnetization circuit and the power splitter.

7. The plurality of inductances is two, the demagnetization circuit has an inner inductance and an outer inductance, the inner inductance corresponds to the inner coil of the ICP chamber, and the outer inductance corresponds to the outer coil of the ICP chamber. The RF generator according to claim 1.

8. The plurality of inductances is three, the demagnetization circuit has an inner inductance, an intermediate inductance, and an outer inductance, the inner inductance corresponds to the inner coil of the ICP chamber, the intermediate inductance corresponds to the intermediate coil of the ICP chamber, and the outer inductance corresponds to the outer coil of the ICP chamber. The RF generator according to claim 1.

9. An RF power source configured to generate an output signal, A power splitter configured to receive the output signal and generate a plurality of split signals, A demagnetization circuit configured to receive the plurality of split signals, the demagnetization circuit being configured to include a plurality of coils corresponding to the plurality of split signals, An RF generator comprising: The plurality of coils is configured to reduce the influence of the mutual impedance of the ICP chamber in series with the plurality of inductances such that the ratio between the pair of the plurality of split signals changes substantially linearly as one of the pair of the plurality of split signals changes. RF generator.

10. The demagnetization circuit includes a plurality of outputs, the plurality of outputs correspond to each one of a plurality of antennas of the ICP chamber, and the combined mutual inductance of the plurality of coils corresponding to the plurality of split signals is substantially equal to the combined mutual inductance of the plurality of antennas of the ICP chamber. The RF generator according to claim 9.

11. The RF generator according to claim 9, further comprising a matching network configured to receive the output signal from the RF power supply and provide the output signal to the power splitter, wherein the matching network is configured to provide impedance matching with the RF power supply.

12. The RF generator according to claim 9, wherein the demagnetization circuit is disposed between the power splitter and the load.

13. The RF generator according to claim 9, wherein the load is disposed between the demagnetization circuit and the power splitter.

14. The RF generator according to claim 9, wherein the plurality of coils is two, the demagnetization circuit has an inner coil and an outer coil, the inner coil corresponds to the inner coil of the ICP chamber, and the outer coil corresponds to the outer coil of the ICP chamber.

15. The RF generator according to claim 9, wherein the plurality of coils is three, the demagnetization circuit has an inner coil, an intermediate coil, and an outer coil, the inner coil corresponds to the inner coil of the ICP chamber, the intermediate coil corresponds to the intermediate coil of the ICP chamber, and the outer coil corresponds to the outer coil of the ICP chamber.

16. A first inductance configured to receive a first RF signal and electrically connected to a first antenna of an ICP chamber; A second inductance configured to receive a second RF signal and electrically connected to a second antenna of an ICP chamber; A demagnetization circuit for an ICP system, comprising: The first inductance and the second inductance are configured to reduce the influence of the mutual impedance of the ICP chamber in series with the first inductance and the second inductance such that the ratio between the first RF signal and the second RF signal changes substantially linearly as one of the first RF signal or the second RF signal changes. A demagnetization circuit for an ICP system. **Claim 17** The first inductance can be one of a first coil having an inductance or a first inductive inductance by conducting current through a first electrical conductor, and the second inductance can be one of a second coil having an inductance or a second inductive inductance by conducting current through a second electrical conductor. The demagnetization circuit for an ICP system according to claim 16. **Claim 18** The combined mutual inductance of the first inductance and the second inductance is substantially equal to the combined mutual inductance of the first antenna and the second antenna of the ICP system. The demagnetization circuit for an ICP system according to claim 16. **Claim 19** The demagnetization circuit is disposed between a power splitter and a load. The demagnetization circuit for an ICP system according to claim 16. **Claim 20** A load is disposed between the demagnetization circuit and a power splitter. The demagnetization circuit for an ICP system according to claim 16.

Images