TWI876038B - Apparatus and method for controlling variable resonance frequency - Google Patents

Abstract

The present disclosure relates to a frequency control apparatus that provides power to a load by controlling a frequency so as to correspond to a variable resonance frequency of the load and includes an inverter configured to convert DC power into AC power with a driving frequency and apply the AC power to the load, a sensor configured to obtain a delay time indicating a phase difference between a voltage and a current of the load at a plurality of time points, a PWM generator configured to provide the inverter with a switching signal corresponding to a second driving frequency different from a first driving frequency by as much as a predetermined frequency on the basis of a first delay time, and a time delay unit configured to reduce the phase difference between the voltage and current of the load as compared with a case in which second AC power is applied to the load by providing the inverter with a switching signal corresponding to third AC power that is different from the second AC power having a second driving frequency by as much as a predetermined phase on the basis of a second delay time.

Description

Device and method for controlling variable harmonic frequency [Cross reference to related applications]

This application claims the priority and rights of Korean Patent Application No. 2020-0055434 filed on May 8, 2020, and the disclosure of the Korean Patent Application is incorporated herein by reference in its entirety.

The present disclosure relates to a frequency control method for precisely controlling frequency and a frequency control device using the same, and more specifically to a method and device for controlling a driving frequency to correspond to a variable resonant frequency of a load by sensing a phase difference between a current and a voltage of the load when alternating current (AC) power is applied to the load.

Technologies using plasma are being used in various industrial fields, including environmental technology fields (e.g., air, water, and soil purification fields), energy technology fields (e.g., solar cells and hydrogen energy fields), and semiconductor, display, and medical equipment technology fields.

There are many methods for generating such plasma, such as direct current (DC) discharge methods including corona discharge, glow discharge, arc discharge, etc., AC discharge methods including capacitive coupled discharge and inductive coupled discharge, shock wave method and high energy beam method. Among these methods, inductive coupled discharge, which uses a simple structure and has a high utilization rate, has attracted attention.

Meanwhile, in order to generate plasma, it is desirable to apply power having an appropriate frequency (e.g., the resonant frequency of the load) to the load generating the plasma. However, due to the generation of plasma, the resonant frequency of the load may change continuously, and it is difficult to control the driving frequency in real time in response to the frequency change. Therefore, a method of controlling the driving frequency to stably generate and maintain plasma is required. In addition, a method of more accurately controlling the driving frequency to approach the resonant frequency is required.

The present disclosure aims to provide a frequency control method capable of providing AC power with a driving frequency that changes in real time to an antenna structure and a device using the same.

The present disclosure also aims to provide a frequency control method and a device using the same that can provide AC power having a driving frequency corresponding to the resonant frequency of the load based on the phase difference between the current and voltage of the load.

The present disclosure also aims to provide a frequency control method capable of using multiple frequency control methods to adjust the driving frequency of AC power applied to a load and a device using the same.

The present disclosure also aims to provide a frequency control method and a device using the same that can adjust the driving frequency of the AC power applied to the load by considering the phase and amplitude of the load's electrical signal.

The present disclosure also aims to provide a frequency control method and a device using the same, wherein the frequency control method is capable of amplifying a signal to be transmitted and transmitting the amplified signal when the signal is transmitted to a switch, and attenuating and receiving the signal.

The problems to be solved by this disclosure are not limited to the above problems, and those familiar with the art in the field to which this disclosure belongs should understand the problems not mentioned above based on this disclosure and the attached drawings.

According to an embodiment of the present application, a device for controlling a variable resonant frequency of a load and providing power to the load can be provided. The device includes: an inverter configured to convert DC power into a first AC power having a first driving frequency and apply the first AC power to the load; a sensor configured to obtain a first delay time and a second delay time, wherein the first delay time represents a phase difference between a current and a voltage of the load at a first time point, and the second delay time represents a phase difference between a current and a voltage of the load at a second time point; a pulse width modulation (Pulse-width modulation) A PWM (PWM) generator is configured to provide a first switching signal to the inverter based on the first delay time, wherein the first switching signal corresponds to a second driving frequency, the second driving frequency differs from the first driving frequency by a predetermined frequency, and the predetermined frequency is determined based on the first delay time for the load; and a time delay unit is configured to provide a second switching signal to the inverter, wherein the second switching signal is determined based on the second delay time and corresponds to a third AC power, wherein for the load, the third AC power differs from the second AC power by a predetermined phase, so that the phase difference between the current and the voltage of the load is reduced compared to the case where the second AC power is applied to the load.

According to another embodiment of the present application, a method for controlling a variable resonant frequency of a load and providing power to the load can be provided. The method includes: applying a first AC power having a first driving frequency to the load using an inverter; obtaining a first delay time representing a phase difference between a current and a voltage of the load at a first time point using a sensor; applying a second AC power having a second driving frequency to the load, wherein the second driving frequency differs from the first driving frequency by a predetermined frequency, and the predetermined frequency is determined based on the first delay time; Using a sensor to obtain a second delay time representing the phase difference between the current and voltage of the load at a second time point; and applying a third AC power to the load, wherein the third AC power differs from the second AC power by a predetermined phase, and the predetermined phase is determined based on the second delay time, so that the phase difference between the current and voltage of the load is reduced compared to the case where the second AC power is applied to the load.

According to another embodiment of the present application, a device for controlling a variable resonant frequency of a load and providing power to the load can be provided. The device includes: an inverter configured to convert DC power into AC power and provide the AC power to the load; a phase detector configured to detect a delay time representing a phase difference between a current and a voltage of the load, wherein the delay time includes a first delay time at a first time point, a second delay time at a second time point, and a third delay time at a third time point; a PWM generator configured to provide a switching signal to the inverter, wherein the switching signal corresponds to a driving frequency set based on the first delay time obtained by the phase detector; a time delay unit configured to The phase detector obtains the third delay time, obtains the current phase signal of the current of the load, delays the current phase signal by a predetermined time based on the third delay time, and provides the delayed current phase signal to the inverter; and a switching circuit is configured to electrically connect one of the PWM generator and the time delay unit to the inverter, and electrically connect the time delay unit to the inverter when the second delay time obtained by the phase detector meets a predetermined condition so that the element connected to the inverter is switched from the PWM generator to the time delay unit.

According to another embodiment of the present application, a method for controlling a variable resonant frequency of a load and providing power to the load can be provided. The method includes: applying AC power having a specific frequency to the load using an inverter; obtaining a delay time representing a phase difference between a current and a voltage of the load using a first sensor; obtaining voltage data representing a voltage of at least a portion of the load using a second sensor; applying AC power having a driving frequency set based on the delay time to the load using the inverter in a first section; and applying AC power having a driving frequency set based on the voltage data to the load using the inverter in a second section.

According to another embodiment of the present application, a device for controlling a variable harmonic frequency of a load and providing power to the load can be provided. The device includes: an inverter configured to convert DC power into AC power and provide the AC power to the load; a phase detector configured to detect a delay time representing a phase difference between a current and a voltage of the load, wherein the delay time includes a first delay time at a first time point, a second delay time at a second time point, and a third delay time at a third time point; a voltage detector configured to detect a voltage of the load at a first time point and a voltage at a second time point, and obtain a first voltage and a second voltage associated with the first delay time. voltage data of a second voltage associated with the second delay time; and a PWM generator configured to provide a switching signal corresponding to a driving frequency set based on the delay time obtained by the phase detector to the inverter, wherein the PWM generator may be configured to provide a switching signal corresponding to a first driving frequency to the inverter when the first voltage is less than the second voltage, wherein the first driving frequency may be set based on the first delay time at a third time point later than the first time point and the second time point.

The technical solutions to the problems in this disclosure are not limited to the above solutions, and those familiar with the technology in the field to which this disclosure belongs should understand the solutions not mentioned above based on this manual and the attached drawings.

According to the present disclosure, AC power with an appropriate frequency can be applied to a load to induce plasma generation and maintain the generated plasma.

According to the present disclosure, by adjusting the driving frequency of the AC power applied to the load to correspond to the variable resonant frequency of the load, the plasma formed by the load can be stably maintained.

According to the present disclosure, a variety of frequency control methods can be used to provide AC power with a driving frequency that further accurately corresponds to the resonant frequency of the load, thereby improving plasma maintenance capabilities.

According to the present disclosure, the amplitude and phase of the electrical signal in the load can be used to provide AC power with a driving frequency that further accurately corresponds to the resonant frequency of the load, thereby improving the plasma maintenance capability.

According to the present disclosure, the switch can be operated while satisfying the zero voltage switching (ZVS) condition and the zero current switching (ZCS) condition or close to the ZCS condition, thereby preventing damage to the switch.

According to the present disclosure, the switch can stably receive electrical signals, thereby preventing the switch from being worn out or damaged.

The effects of this disclosure are not limited to the above effects, and those familiar with the art in the field to which this disclosure belongs can clearly understand the effects not mentioned based on this specification and the attached drawings.

100: Plasma system

1000: Radio frequency (RF) generator

1100:AC power supply

1200: Rectifier

1300: Inverter

1400:Sensor module

1410: Inverter

1420:Filter

1430: Comparator

1500: Controller

1510: Phase detector

1520:PWM generator

1530:Switching circuit

1540: Time delay unit

1600: Voltage detector

1710: Voltage amplifier

1720: Voltage attenuator

1730: Voltage-to-optical converter

1740:Optical-to-voltage converter

2000: Antenna structure

2100: First Antenna

2200: Second antenna

2300: The third day line

3000: Plasma generation unit

dt, t_interval: time interval

f0: harmonic frequency

f1: first driving frequency

f2: Second driving frequency

f3: third drive frequency

f4: fourth drive frequency

f_interval: frequency interval

f_start: starting frequency

GND: ground node

I _RF : Current

S1: First switch

S2: Second switch

S3: The third switch

S4: The fourth switch

S1000: Digital frequency control method

S1100, S1200, S1300, S1400, S2100, S2200, S2300, S2400, S2500, S2600, S3100, S3200, S3300, S3400, S3500, S3600: Operation

S2000: High-resolution frequency control method

S3000: Precision frequency control method

SW: switch signal

td1: first delay time

td2: Second delay time

td3: third delay time

V _RF : Voltage

The above and other objects, features and advantages of the present disclosure will become more apparent to those skilled in the art by describing in detail exemplary embodiments of the present disclosure with reference to the accompanying drawings, wherein: FIG. 1 is a diagram related to a plasma system according to an embodiment of the present specification; FIG. 2 is a diagram related to a radio frequency (RF) generator according to an embodiment of the present specification; FIG. 3 is a diagram related to an antenna structure according to an embodiment of the present specification; FIG. 4 is a diagram related to a structure of an RF generator for digital frequency control according to an embodiment of the present specification; FIG. 5 is a diagram related to a digital frequency control method according to an embodiment of the present specification; FIG. 6 is a diagram related to a method for controlling a radio frequency according to an embodiment of the present specification; FIG. 7 is a diagram related to the structure of an RF generator for high-resolution frequency control according to an embodiment of the present specification; FIG. 8 is a diagram related to a high-resolution frequency control method according to an embodiment of the present specification; FIG. 9 is a diagram related to a driving frequency controlled according to high-resolution frequency control according to an embodiment of the present specification. FIG. 10 is a graph related to the change of the current phase difference and the voltage phase difference of the load in the high-resolution frequency control according to an embodiment of the present specification; FIG. 11 is a graph related to the structure of the RF generator for fine frequency control according to an embodiment of the present specification; FIG. 12 is a graph related to the fine frequency control method according to an embodiment of the present specification; FIG. FIG. 3 is a graph related to the phase difference between the voltage and current of the load in the fine frequency control according to an embodiment of the present specification; FIG. 14 is a graph related to a method of transmitting and receiving a switching signal using an amplifier and an attenuator according to an embodiment of the present specification; and FIG. 15 is a graph related to a method of transmitting and receiving a switching signal using an optical converter according to an embodiment of the present specification.

The above-mentioned objects, features and advantages of the present disclosure will become more apparent from the following detailed description in conjunction with the accompanying drawings. However, it should be understood that the present disclosure can be modified into various forms and have various embodiments, and in the following, specific embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

Since the embodiments described in this article are intended to clearly explain the concept of the present disclosure to those skilled in the art in the field to which the present disclosure belongs, the present disclosure is not limited to the embodiments described in this article, and the scope of the present disclosure should be understood to include changed examples and modified examples without departing from the spirit of the present disclosure.

The accompanying drawings are intended to easily illustrate the description of the present disclosure, and the shapes shown in the drawings may be shown in an exaggerated manner as needed to help understand the present disclosure, and therefore the present disclosure is not limited to the drawings.

Detailed descriptions of known functions and configurations incorporated herein will be omitted when they may unnecessarily obscure the subject matter of the present disclosure. In addition, the numbers used in the description of the present disclosure (e.g., first, second, etc.) are merely identifiers used to distinguish one element from another.

In addition, the suffixes "unit", "module" and "component" used in the following description are given or used interchangeably for the convenience of drafting the description and do not have their own distinguishing meanings or functions.

According to an embodiment of the present application, a device for controlling a variable resonant frequency of a load and providing power to the load can be provided. The device includes: an inverter configured to convert DC power into a first AC power having a first driving frequency and apply the first AC power to the load; a sensor configured to obtain a first delay time and a second delay time, wherein the first delay time represents a phase difference between a current and a voltage of the load at a first time point, and the second delay time represents a phase difference between a current and a voltage of the load at a second time point; a PWM generator configured to provide a first switching signal to the inverter based on the first delay time, wherein the first switching signal is sensitive to the first switching signal. A second driving frequency is provided, the second driving frequency differs from the first driving frequency by a predetermined frequency, the predetermined frequency is determined based on the first delay time for the load; and a time delay unit is configured to provide a second switching signal to the inverter, wherein the second switching signal is determined based on the second delay time and corresponds to a third AC power, wherein for the load, the third AC power differs from the second AC power by a predetermined phase, so that the phase difference between the current and the voltage of the load is reduced compared to the case where the second AC power is applied to the load.

Herein, the predetermined frequency may be greater than the frequency difference between the second driving frequency and the third driving frequency corresponding to the third AC power.

Herein, the time delay unit may be configured to receive the phase signal of the load and delay the phase signal by the predetermined phase to obtain the second switching signal, and is configured to output the obtained second switching signal, and the phase signal of the load may indicate the phase of the current of the load.

Herein, the predetermined phase may include a phase corresponding to the second delay time.

Herein, the device may further include: a switching circuit configured to electrically connect at least one of the PWM generator and the time delay unit to the inverter.

Herein, the switching circuit may be configured to switch the PWM generator connected to the inverter by means of the time delay unit when the second delay time satisfies a predetermined condition.

Herein, the device may further include: a clock source having a predetermined clock frequency, wherein the predetermined frequency can be obtained by dividing the clock frequency by an integer, and wherein the predetermined phase is an integer multiple of the reciprocal value of the clock frequency.

Herein, the device may further include: a phase sensing unit configured to periodically obtain and provide the phase signal of the load, wherein the sensor may be configured to periodically obtain a delay time and provide the delay time to the time delay unit, and wherein the time delay unit may be configured to provide a switching signal to the inverter, wherein the switching signal is obtained by delaying the phase signal based on the delay time.

Herein, the device may further include: an amplifier electrically connected to the switch circuit and configured to amplify the signal; and an attenuator connected to the inverter and configured to attenuate the signal, wherein the critical voltage of the attenuator may be greater than the critical voltage of the inverter to prevent noise.

Herein, the device may further include: a first converter electrically connected to the switching circuit and configured to convert an electrical signal into an optical signal; and a second converter electrically connected to the inverter and configured to convert the optical signal into an electrical signal, wherein the switching circuit may be configured to provide the first switching signal or the second switching signal to the inverter via the first converter and the second converter.

According to another embodiment of the present application, a method for controlling a variable resonant frequency of a load and providing power to the load may be provided. The method may include: applying a first AC power having a first driving frequency to the load using an inverter; obtaining a first delay time representing a phase difference between a current and a voltage of the load at a first time point using a sensor; applying a second AC power having a second driving frequency to the load, wherein the second driving frequency differs from the first driving frequency by a predetermined frequency, and the predetermined frequency is determined based on the first delay time; Using a sensor to obtain a second delay time representing the phase difference between the current and voltage of the load at a second time point; and applying a third AC power to the load, wherein the third AC power differs from the second AC power by a predetermined phase, and the predetermined phase is determined based on the second delay time, so that the phase difference between the current and voltage of the load is reduced compared to the case where the second AC power is applied to the load.

Herein, the method may further include: using a PWM generator to provide a first switching signal corresponding to the first driving frequency to the inverter; using the PWM generator to provide a second switching signal corresponding to the second driving frequency to the inverter; and using a time delay unit to provide a third switching signal corresponding to the third AC power to the inverter, wherein the third switching signal may be obtained by delaying the phase signal of the load.

Herein, the phase signal may be a current phase signal of the load before the AC power having the third driving frequency is applied to the load.

According to another embodiment of the present application, a device for controlling a variable resonant frequency of a load and providing power to the load can be provided. The device may include: an inverter configured to convert DC power into AC power and provide the AC power to the load; a phase detector configured to detect a delay time representing a phase difference between a current and a voltage of the load, wherein the delay time includes a first delay time at a first time point, a second delay time at a second time point, and a third delay time at a third time point; a PWM generator configured to provide a switching signal to the inverter, wherein the switching signal corresponds to a driving frequency set based on the first delay time obtained by the phase detector; a time delay unit configured to detect a phase difference between the current and the voltage of the load, wherein the delay time includes a first delay time at a first time point, a second delay time at a second time point, and a third delay time at a third time point; a PWM generator configured to provide a switching signal to the inverter, wherein the switching signal corresponds to a driving frequency set based on the first delay time obtained by the phase detector; and a time delay unit configured to detect a phase difference between the current and the voltage of the load. The phase detector obtains the third delay time, obtains the current phase signal of the current of the load, delays the current phase signal by a predetermined time based on the third delay time, and provides the delayed current phase signal to the inverter; and a switching circuit is configured to electrically connect one of the PWM generator and the time delay unit to the inverter, and electrically connect the time delay unit to the inverter when the second delay time obtained by the phase detector meets a predetermined condition so that the element connected to the inverter is switched from the PWM generator to the time delay unit.

Herein, the PWM generator may be configured to provide the switching signal so that the frequency of the AC power applied to the load changes from the first driving frequency to the second driving frequency, the time delay unit may be configured to delay the current phase signal so that the frequency of the AC power applied to the load changes from the third driving frequency to the fourth driving frequency, and is configured to provide the delayed current phase signal to the inverter, and the difference between the first driving frequency and the second driving frequency may be greater than the difference between the third driving frequency and the fourth driving frequency.

Herein, the PWM generator may be configured to provide the switching signal so that the frequency of the AC power applied to the load changes from the first driving frequency to the second driving frequency, the time delay unit may be configured to delay the current phase signal so that the frequency of the AC power applied to the load changes from the third driving frequency to the fourth driving frequency, and is configured to provide the delayed current phase signal to the inverter, and the difference between the first driving frequency and the second driving frequency may be greater than the difference between the third driving frequency and the fourth driving frequency.

Herein, the predetermined condition can be set at least within a range between -5 nanoseconds and 20 nanoseconds.

According to another embodiment of the present application, a method for controlling a variable resonant frequency of a load and providing power to the load can be provided. The method may include: applying AC power having a specific frequency to the load using an inverter; obtaining a delay time representing a phase difference between a current and a voltage of the load using a first sensor; obtaining voltage data representing a voltage of at least a portion of the load using a second sensor; applying AC power having a driving frequency set based on the delay time to the load using the inverter in a first section; and applying AC power having a driving frequency set based on the voltage data to the load using the inverter in a second section.

Herein, the method may further include: using the first sensor to determine a frequency range based on the first delay time and the second delay time obtained in the first section; selecting a final maintenance frequency within the frequency range based on the voltage data; and using the inverter to apply AC power having the final maintenance frequency to the load, wherein the first delay time and the second delay time may meet a predetermined condition.

Herein, the frequency range may include at least a first driving frequency and a second driving frequency, the voltage data may include at least a first voltage and a second voltage, the first voltage may be obtained when an AC power having the first driving frequency is applied to the load, and the second voltage may be obtained when an AC power having the second driving frequency is applied to the load, and when the second voltage is less than the first voltage, the second driving frequency may be selected as the final maintenance frequency.

Herein, the phase difference between the current and the voltage of the load in the second section can meet a predetermined condition.

Herein, the predetermined condition can be set at least within a range between -5 nanoseconds and 20 nanoseconds.

Herein, the load may include an antenna structure, the antenna structure including a first antenna having a first radius of curvature and a second antenna having a second radius of curvature, the second radius of curvature being larger than the first radius of curvature, and the voltage data may be obtained by measuring the voltage of the first antenna using the second sensor.

Herein, the load may include an antenna structure, the antenna structure including a first antenna having a first radius of curvature and a second antenna having a second radius of curvature, the second radius of curvature being larger than the first radius of curvature, and the voltage data may be obtained by measuring the voltage of the first antenna and the voltage of the second antenna using the second sensor.

According to another embodiment of the present application, a device for controlling a variable resonant frequency of a load and providing power to the load may be provided. The device may include: an inverter configured to convert DC power into AC power and provide the AC power to the load; a phase detector configured to detect a delay time representing a phase difference between a current and a voltage of the load, wherein the delay time includes a first delay time at a first time point, a second delay time at a second time point, and a third delay time at a third time point; a voltage detector configured to detect a voltage of the load at a first time point and a voltage at a second time point, and obtain a first voltage and a second voltage associated with the first delay time. voltage data of a second voltage associated with the second delay time; and a PWM generator configured to provide a switching signal corresponding to a driving frequency set based on the delay time obtained by the phase detector to the inverter, wherein the PWM generator may be configured to provide a switching signal corresponding to a first driving frequency to the inverter when the first voltage is less than the second voltage, wherein the first driving frequency may be set based on the first delay time at a third time point later than the first time point and the second time point.

Herein, the device may further include: an amplifier electrically connected to the PWM generator and configured to amplify the signal; and an attenuator electrically connected to the inverter and configured to attenuate the signal, wherein the critical voltage of the attenuator may be greater than the critical voltage of the inverter to prevent noise.

Herein, the device may further include: a first converter electrically connected to the PWM generator and configured to convert an electrical signal into an optical signal; and a second converter electrically connected to the inverter and configured to convert the optical signal into an electrical signal, wherein the PWM generator may be configured to provide the first switching signal or the second switching signal to the inverter via the first converter and the second converter.

This manual is about a frequency control method for accurately controlling frequency and a frequency control device using the same.

Specifically, in a frequency control method and a frequency control device using the same according to an embodiment of the present specification, when power having a specific driving frequency is applied to a load, the driving frequency can be changed periodically or in real time.

Herein, driving frequency may refer to the frequency of the power applied to the load.

Herein, a load may refer to a component that is powered. For example, a load may refer to an electrical component representing a circuit including electrical components such as resistors, inductors, and capacitors. Depending on the properties or characteristics of the electrical components constituting the load, the load may have a resonant frequency. At this time, the resonant frequency may change in real time according to the load.

In the following, for the sake of convenience, the frequency control method and the frequency control device using the same will be described for the plasma system, but the technical spirit of this specification is not limited thereto, and of course the frequency control method and the frequency control device using the same can be similarly applied to devices or applications in which AC power needs to be applied while adjusting its driving frequency in real time. For example, the frequency control method and the device using the same to be described below can be used in the field of wireless power transmission, the field of induction heating, etc. to control the driving frequency of AC power to correspond to the variable resonant frequency of the load.

According to one embodiment of the present specification, in a plasma system for generating and maintaining plasma, a frequency control method can be used to apply power to an antenna or an antenna structure.

Here, plasma is a phase in which a material receives high energy to be separated into positively charged ions and negatively charged electrons, and can be induced or generated by various methods. Among them, inductively coupled plasma (ICP) is plasma generated by an induced electric field or capacitive electric field formed in a specific space when power is supplied to a coil, antenna, etc., and can generally be driven by high-frequency power (e.g., radio frequency (RF) power). At the same time, in the following, for the sake of convenience, it will be assumed that the plasma generated by the plasma system is ICP for explanation, but the technical spirit of this specification is not limited to this.

Here, the antenna may be an inductive element or load that forms an electric field or a magnetic field around it when a voltage or current is applied thereto, and may refer to a coil, an inductor, etc. In addition, the antenna may refer to an equivalent circuit implemented by elements other than an inductive element.

Herein, an antenna structure may refer to a structure including one or more antennas. In addition, the antenna structure may include one or more capacitive elements or loads and may be implemented in a form in which one or more antennas or one or more capacitive elements may be connected or arranged in a specific manner.

Meanwhile, the plasma system according to an embodiment of the present specification can be widely used in various fields, such as semiconductor, display processing, environment and energy fields. It should be noted in advance that the plasma generating device to be described below is not limited to use in only a specific field, and can be used in common in the field using plasma.

Hereinafter, a plasma system according to an embodiment of the present specification will be described with reference to FIG. 1.

FIG. 1 is a diagram related to a plasma system 100 according to an embodiment of the present specification. Referring to FIG. 1 , the plasma system 100 may include a radio frequency (RF) generator 1000, an antenna structure 2000, and a plasma generating unit 3000. The plasma system 100 may use the RF generator 1000 to supply RF power to the antenna structure 2000 to induce ICP in the plasma generating unit 3000.

The RF generator 1000 may provide power to the antenna structure 2000. For example, the RF generator 1000 may apply AC power having a specific driving frequency to the antenna structure 2000. In this case, the driving frequency of the AC power provided to the antenna structure 2000 may be changed as described below.

The antenna structure 2000 may include at least one antenna. Alternatively, the antenna structure 2000 may include at least one antenna and at least one capacitor. The components and structure of the antenna structure 2000 will be described in detail below.

The antenna structure 2000 can be electrically connected to the RF generator 1000. The antenna structure 2000 and the RF generator 1000 can be connected in series or in parallel with each other via conductive wires, or can be connected in series or in parallel with each other via electrical components.

The antenna structure 2000 can be physically or electrically connected to the plasma generating unit 3000. The connection relationship between the antenna structure 2000 and the plasma generating unit 3000 will be described in detail below.

When the antenna structure 2000 receives RF power from the RF generator 1000, a time-varying current may flow in the antenna structure, and based on this, an induced electric field is generated in the plasma generating unit 3000, thereby inducing plasma.

The antenna structure 2000 may have a resonant frequency according to its components. Here, the resonant frequency may refer to the resonant frequency of the antenna structure 2000 itself. Alternatively, the resonant frequency may refer to the resonant frequency in which the influence of the antenna structure 2000 and the plasma generated is taken into account. For example, when the plasma system 100 forms plasma, in order to minimize the phase difference between the voltage and current in the antenna structure 2000 while maintaining the plasma, the driving frequency applied to the antenna structure 2000 from the RF generator 1000 needs to be changed in real time, and in this case, it can be seen that the resonant frequency changes due to the plasma generated in the antenna structure 2000 and the plasma generating unit 3000.

The plasma generating unit 3000 may include a region or space in which plasma generation is induced. Specifically, the plasma generating unit 3000 may refer to a space (e.g., a chamber or a tube) in which plasma may be generated and maintained.

In the following, the components and structure of the RF generator 1000 will be described with reference to FIG. 2.

FIG. 2 is a diagram related to an RF generator 1000 according to an embodiment of the present specification.

2, the RF generator 1000 may include an AC power source 1100, a rectifier 1200, an inverter 1300, a controller 1500, and a sensor module 1400. The RF generator 1000 may convert the first AC power supplied from the AC power source 1100 into a second AC power and supply the second AC power to a load. For example, the RF generator 1000 may convert the first AC power used in a conventional household or industry into a second AC power having a frequency of hundreds of kilohertz (kHz) to tens of megahertz (MHz) and a power of several kilowatts (kW) or more and supply the second AC power to a load.

Here, the load may include the antenna structure 2000 and plasma generated by the antenna structure 2000. The load may have a resonant frequency that varies with time according to the induced plasma.

The rectifier 1200 may convert the output of the AC power source 1100 into DC power. The rectifier 1200 may convert the first AC power supplied from the AC power source 1100 into DC power and apply the DC power to both ends of the inverter 1300.

The inverter 1300 may receive DC power from the rectifier 1200 and supply the second AC power to the load. For example, the inverter 1300 may receive a switching signal SW from the controller 1500 and supply the second AC power to the load using the received switching signal. Here, the inverter 1300 may include at least one switching element controlled by the switching signal, and the second AC power supplied from the inverter 1300 to the load may have a driving frequency set based on the switching signal received by the inverter 1300 from the controller 1500. For example, the inverter 1300 may be provided as a half-bridge type or a full-bridge type.

According to the frequency control method of the controller 1500, the inverter 1300 may be controlled using a time delay method, a pulse width modulation method, or a combination thereof.

Meanwhile, a capacitive element may be disposed between the rectifier 1200 and the inverter 1300. For example, the RF generator 1000 may include a capacitor connected in parallel to the rectifier 1200 and the inverter 1300, and the capacitor allows the AC component of the power applied to the inverter 1300 to be discharged to the ground node GND.

The controller 1500 may receive sensed data from the sensor module 1400 (which will be described below) to generate a switching signal. For example, the controller 1500 may be implemented to obtain data related to the resonant frequency of the load (e.g., current and voltage) from the sensor module 1400 to generate a switching signal. Specifically, the controller 1500 may use the phase data of the current applied to the load and the phase data of the voltage applied to the load obtained from the sensor module 1400 to obtain phase difference data or delay time, and based on this, the controller 1500 may generate a switching signal. The controller 1500 may be implemented using field programmable gate array (FPGA) technology. The specific components and structure of the controller 1500 will be described below.

The sensor module 1400 may provide the controller 1500 with data related to the resonant frequency of the load or data related to the power supplied to the load. Referring again to FIG. 2 , the sensor module 1400 may include a current transformer 1410, a filter 1420, and a comparator 1430. The sensor module 1400 may receive a current signal flowing through the load or a voltage signal flowing through the current transformer 1410, convert the current or voltage signal into a current or voltage signal with different amplitudes, filter the converted current or voltage signal using the filter 1420, and output phase data to the controller 1500 through the comparator 1430.

Here, the converter 1410 may be inductively coupled to the wiring between the inverter 1300 and the load, and may convert the voltage or current signal applied to the load to provide the converted voltage or current signal to the filter 1420. Specifically, the converter 1410 may convert the current flowing through the conductive wire connected to the load into a voltage signal.

Here, the filter 1420 can remove the DC component from the received current or voltage signal, and output the DC-removed current or voltage signal to the comparator 1430. To this end, the filter 1420 can implement high-band pass filtering or low-band pass filtering.

Here, the comparator 1430 may obtain phase data. For example, the comparator 1430 may obtain phase data by comparing a voltage signal obtained from the inverter 1410 or the filter 1420 with a predetermined value. In this case, the phase data may refer to phase data of a current applied to a load.

At least one of the components included in the above-mentioned sensor module 1400 may be omitted.

Although not shown in FIG. 2 , the RF generator 1000 may include a memory.

Here, the memory may store various data. The memory may store various data temporarily or semi-permanently. Examples of the memory may include a hard disk drive (HDD), a solid-state drive (SSD), a flash memory, a read-only memory (ROM), a random access memory (RAM), etc. The memory may be provided in a form embedded in the RF generator 1000 or in a form that may be attached to and detached from the RF generator 1000.

As described above, the RF generator 1000 can control the driving frequency of the second AC power supplied to the load based on data related to the resonant frequency of the load. In other words, the RF generator 1000 can track the resonant frequency of the load that changes according to plasma generation, and output the driving frequency of the second AC power to correspond to the resonant frequency of the load. Therefore, unnecessary power consumption can be prevented and the durability of the plasma system can be improved.

At least one of the above components of the RF generator 1000 may be omitted. For example, the RF generator 1000 may obtain electrical data of the load from an external sensor without including the sensor module 1400. As another example, the RF generator 1000 may receive DC power or rectified DC power from the outside without including the AC power source 1100 and the rectifier 1200.

In the following, the plasma-induced antenna structure 2000 will be described with reference to FIG. 3.

FIG3 is a diagram related to an antenna structure 2000 according to an embodiment of the present specification.

3 , the antenna structure 2000 may include a plurality of antennas disposed around the plasma generating unit 3000. Specifically, the antenna structure 2000 may include first antenna 2100 to third antenna 2300 having different curvature radii.

The first antenna 2100 may be arranged to be closer to the plasma generating unit 3000 than other antennas. For example, the first antenna 2100 may have a smaller radius of curvature than other antennas, and may be arranged so that the inner diameter surface contacts the plasma generating unit 3000.

The second antenna 2200 may have a larger radius of curvature than the first antenna 2100 and may be disposed between the first antenna 2100 and the third antenna 2300.

The third antenna 2300 may have a larger radius of curvature than the second antenna 2200 and may be disposed at the outermost side of the antenna structure.

The first antenna 2100 to the third antenna 2300 may be designed in various shapes. For example, referring again to FIG. 3 , each of the first antenna 2100 to the third antenna 2300 may have a circular ring shape with a rectangular cross section or a rectangular ring shape with a circular cross section.

The first antenna 2100 to the third antenna 2300 may be electrically connected to each other. For example, one end of the first antenna 2100 may be electrically connected to one end of the second antenna 2200, and the other end of the second antenna 2200 may be electrically connected to one end of the third antenna 2300. As another example, the first antenna 2100 and the second antenna 2200 may be electrically connected via an electrical connection element (e.g., a capacitor), and the second antenna 2200 and the third antenna 2300 may be electrically connected via an electrical connection element (e.g., a capacitor).

When power is applied to the first antenna 2100 to the third antenna 2300, the first antenna 2100 to the third antenna 2300 may generate an induced electric field inside the plasma generating unit 3000 to induce plasma. At this point, as described below, the driving frequency of the AC power applied to the antenna structure 2000 may be controlled using the electrical characteristics of at least one of the first antenna 2100 to the third antenna 2300.

Unlike what is shown in FIG. 3 , in addition to the above-mentioned shape or structure, the antenna structure 2000 may have another shape or structure that induces inductively coupled plasma. For example, the number of antennas included in the antenna structure 2000 is not necessarily three, and the antenna structure 2000 may include three, less than three, or more than three antennas. As another example, the antenna structure 2000 may include antennas disposed in different planes. Specifically, the antenna structure 2000 may include at least one antenna that surrounds the plasma generating unit 3000 and is disposed on a first plane and at least one antenna that surrounds the plasma generating unit 3000 and is disposed on a second plane different from the first plane. In this case, the antennas of different planes may be electrically connected directly or electrically connected via a separate electrical connection element (e.g., a capacitor). As another example, the antenna structure 2000 may include at least one antenna, and each antenna may include a plurality of antenna segments and capacitors electrically connected between the antenna segments.

The antenna structure 2000 may be electrically connected to the RF generator 1000. For example, one end of the RF generator 1000 is electrically connected to the end of the first antenna 2100, and the other end of the RF generator 1000 is electrically connected to the end of the third antenna 2300, and thus the RF generator 1000 may supply power to the antenna structure 2000. As another example, the RF generator 1000 may be connected to the antenna structure 2000 by a separate electrical element. Specifically, each of the ends of the first antenna 2100 and the third antenna 2300 may be connected to a capacitor, and each capacitor may be connected to the RF generator 1000.

Hereinafter, a frequency control method according to an embodiment of the present specification will be described. The RF generator 1000 can adjust the frequency of the AC power applied to the antenna structure 2000 by the frequency control method. Specifically, the RF generator 1000 can change or set the driving frequency in real time by sensing the resonant frequency or electrical properties (e.g., current and voltage) of the load including the antenna structure 2000 in real time, for forming and maintaining plasma.

In the following, the digital frequency control method will be described with reference to Figures 4 to 6.

FIG4 is a diagram related to the structure of an RF generator 1000 for digital frequency control according to an embodiment of the present specification.

Referring to FIG. 4 , the RF generator 1000 may include an inverter 1300, a sensor module 1400, and a controller 1500, wherein the controller 1500 includes a phase detector 1510 and a PWM generator 1520. The RF generator 1000 may use the sensor module 1400 to obtain current phase data, use the phase detector 1510 to obtain phase difference data or delay time between current and voltage, and use the PWM generator 1520 to provide a switching signal to the inverter 1300.

The inverter 1300 can receive DC power, convert the DC power into AC power, and provide the AC power to the load. To this end, the inverter 1300 can be set to a half-bridge type or a full-bridge type. In the following, for the convenience of explanation, the inverter 1300 is explained as being provided as a full-bridge type, but the technical spirit of this specification is not limited to this.

The inverter 1300 may include first to fourth switches S1 to S4.

Here, each of the first to fourth switches S1 to S4 can be turned on or off by receiving a switching signal from the PWM generator 1520. Here, when the first and third switches S1 and S3 are turned on and the second and fourth switches S2 and S4 are turned off, a positive voltage can be applied to the load, and when the first and third switches S1 and S3 are turned off and the second and fourth switches S2 and S4 are turned on, a negative voltage can be applied to the load. As described above, the inverter 1300 can alternately apply positive and negative voltages to the load, thereby applying AC power having a specific frequency.

The sensor module 1400 can detect the phase of the current flowing through the load. As described in FIG. 2 , the sensor module 1400 can be electrically coupled to the load to obtain a current signal corresponding to the current flowing through the load, and can obtain current phase data indicating the phase of the current flowing through the load based on the obtained current signal. In this case, the current phase data can be used in the same meaning as the current phase signal. Alternatively, the sensor module 1400 can obtain a voltage signal corresponding to the voltage applied to the load, and obtain phase data of the current flowing through the load based on the obtained voltage signal.

The phase detector 1510 may obtain phase data of a current flowing through the load and a voltage applied to the load. The phase detector 1510 may obtain current phase data from the sensor module 1400. The phase detector 1510 may obtain a switching signal provided to the inverter 1300 as voltage phase data. In this case, the switching signal may indicate the phase of the voltage applied to the load, and the switching signal may include at least one of the switching signals provided to the first switch S1 to the fourth switch S4. To this end, the phase detector 1510 may receive the switching signal from the PWM generator 1520.

The phase detector 1510 can obtain delay time or phase difference data. The phase detector 1510 can obtain current phase data and voltage phase data to obtain delay time or phase difference data indicating the difference between the current phase data and the voltage phase data.

Here, the delay time or phase difference data may refer to the phase difference between the current flowing through the load and the voltage applied to the load. In the following, for ease of explanation, it is mainly explained that the phase detector 1510 obtains the delay time, but the situation in which the phase detector 1510 obtains the phase difference data can be similarly applied. The delay time can be expressed as a phase or a time. The delay time may refer to the phase difference or delay time of the current flowing through the load relative to the voltage applied to the load, or the phase difference or delay time of the voltage applied to the load relative to the current flowing through the load. The RF generator 1000 can adjust the driving frequency of the AC power applied to the load based on the obtained delay time.

Furthermore, here, the delay time can be stored in memory. For example, the delay time can be measured in real time and stored in the memory in a phase format or a time format and loaded as needed.

Although the phase detector 1510 is described as obtaining the delay time using the current phase data obtained from the sensor module 1400 and the switching signal obtained from the PWM generator 1520, the technical spirit of this specification is not limited thereto. For example, the RF generator 1000 can directly measure the voltage applied to the load and the current flowing through the load, obtain the corresponding phase data, and generate a switching signal provided to the inverter 1300.

The PWM generator 1520 can generate a switching signal and provide the switching signal to the inverter 1300.

As an example, the PWM generator 1520 may generate a switching signal to correspond to a driving frequency obtained by increasing or decreasing the frequency of AC power applied to the load at a previous time point, and provide the switching signal to the inverter 1300. For example, the PWM generator 1520 may generate the switching signal based on a predetermined first in-phase recognition condition. Specifically, in a case where the predetermined first in-phase identification condition is -5 nanoseconds to 15 nanoseconds, when the delay time is 15 nanoseconds or greater, a switching signal may be generated based on a frequency lower than the driving frequency at the previous time point, and when the delay time is -5 nanoseconds or less, a switching signal may be generated based on a frequency higher than the driving frequency at the previous time point. Here, when the delay time satisfies the first in-phase identification condition, the PWM generator 1520 may generate a switching signal so that the driving frequency at the previous time point is maintained.

The first in-phase identification condition can be set by considering the frequency band used in the frequency control method, the stability of the frequency control device, the power transmission efficiency, etc.

The lower limit value of the first in-phase identification condition can be set to a value at which the switch in the inverter 1300 can be switched by zero voltage switching (ZVS). For example, when the driving frequency is less than the resonant frequency of the load, the phase of the applied current is delayed more than the phase of the applied voltage, so that the switch in the inverter 1300 may be hard-switched, thereby causing damage to the switch. Therefore, the lower limit value of the first in-phase identification condition can be set to meet the condition that the switch in the inverter 1300 is not hard-switched.

The upper limit value of the first in-phase identification condition may be set to a value at which the switch in the inverter 1300 may approach zero current switching (ZCS). For example, when the driving frequency is greater than the resonant frequency of the load, since the phase of the applied voltage may be delayed more than the phase of the applied current, switching noise may be generated, and the power provided to the load may be reduced, and thus it may be difficult to maintain plasma. Therefore, the upper limit value of the first in-phase identification condition may be set to a value that satisfies the ZCS of the inverter 1300 and maintains plasma.

As described above, the lower limit value and the upper limit value of the first in-phase identification condition can be appropriately selected in consideration of ZVS, ZCS, plasma maintenance, etc., and can be set differently according to the frequency band used. Therefore, the above-mentioned -5 nanoseconds to 15 nanoseconds as the first in-phase identification condition are values according to examples, and can be set differently as needed. For example, the first in-phase identification condition can be set to -10 nanoseconds to 20 nanoseconds. As another example, when the frequency band used is close to 2 MHz, the first in-phase identification condition can be set to -15 nanoseconds to 40 nanoseconds.

As another example, the PWM generator 1520 may set a driving frequency based on a delay time, generate a switching signal to correspond to the set driving frequency, and provide the switching signal to the inverter 1300. Specifically, the PWM generator 1520 may generate a switching signal by setting a frequency corresponding to a delay time obtained using a lookup table as the driving frequency. Alternatively, the PWM generator 1520 may generate a switching signal by setting a frequency corresponding to a delay time obtained using a predetermined function as the driving frequency.

The PWM generator 1520 can determine whether the current flowing through the load lags behind or leads the voltage applied to the load based on the delay time.

FIG5 is a diagram related to a digital frequency control method (S1000) according to an embodiment of the present specification.

Referring to FIG. 5 , the digital frequency control method ( S1000 ) may include: obtaining current phase data and voltage phase data ( S1100 ); obtaining a delay time between current and voltage ( S1200 ); setting a driving frequency using a first in-phase identification condition ( S1300 ); and providing a switching signal to the inverter 1300 based on the driving frequency ( S1400 ).

In the following, each operation of the digital frequency control method (S1000) will be described in detail.

The RF generator 1000 can obtain current phase data and voltage phase data (S1100). The RF generator 1000 can obtain the phase data of the current flowing through the load from the sensor module 1400. The RF generator 1000 can obtain the phase data of the voltage applied to the load from the PWM generator 1520. Alternatively, the RF generator 1000 can directly measure the current and voltage of the load to obtain the phase data of the current and voltage.

The RF generator 1000 can obtain the delay time between the current and the voltage (S1200). The RF generator 1000 can use the phase detector 1510 to obtain the delay time of the current relative to the voltage or the delay time of the voltage relative to the current.

The RF generator 1000 may use the first in-phase identification condition to set the driving frequency (S1300). The RF generator 1000 may set the driving frequency by comparing the delay time obtained in the delay time acquisition operation (S1200) with the first in-phase identification condition. Specifically, when the delay time is greater than the first in-phase identification condition, the driving frequency may be reduced, and when the delay time is less than the first in-phase identification condition, the driving frequency may be increased. The RF generator 1000 may use a predetermined function to set the driving frequency corresponding to the delay time, or use a lookup table to set the driving frequency corresponding to the delay time.

The use of the first in-phase identification condition to set the driving frequency (S1300) may be omitted. The controller 1500 may generate a switching signal using the obtained delay time and provide the switching signal to the inverter 1300.

The controller 1500 may provide a switching signal to the inverter 1300 based on the driving frequency (S1400). For example, the controller 1500 may generate a switching signal so that the inverter 1300 operates at the set driving frequency or at a frequency with a reduced delay time amplitude.

The inverter 1300 may receive a switching signal from the controller 1500 to operate the switch. In this case, the first switch S1 and the third switch S3 may receive the switching signal as is, and the second switch S2 and the fourth switch S4 may receive the switching signal in an inverted state, and thus the first switch S1 and the third switch S3 and the second switch S2 and the fourth switch S4 may be alternately turned on or off.

The controller 1500 may control the inverter 1300 based on the driving frequency set according to the digital frequency control, but the controller 1500 may detect that the resonant frequency of the load changes while maintaining the plasma, and operate the inverter 1300 at a driving frequency different from the existing driving frequency by implementing the above-mentioned digital frequency control method (S1000) again.

FIG. 6 is a graph showing a driving frequency change according to digital frequency control according to an embodiment of the present specification.

Referring to FIG. 6 , at the plasma induction start time point, the RF generator 1000 operates the inverter 1300 at the start frequency f_start, and after a predetermined time has passed according to the digital frequency control, the RF generator 1000 operates the inverter 1300 at the first driving frequency f1 or the second driving frequency f2.

The starting frequency f_start may refer to the driving frequency at the time point when the inverter 1300 is driven by the controller 1500.

As an example, the start frequency f_start may be set based on the resonant frequency f0. Here, the resonant frequency f0 may refer to the natural frequency or resonant frequency of the antenna structure 2000 itself, or the natural frequency or resonant frequency of the load including the antenna structure 2000. The resonant frequency f0 may be changed according to plasma generation.

As another example, the starting frequency f_start can be set arbitrarily and is independent of the resonance frequency f0. Specifically, the starting frequency f_start can be set based on the size of the antenna structure 2000. Alternatively, the starting frequency f_start can be set based on the size or scale of the plasma to be induced in the plasma system 100.

The starting frequency f_start can be greater or less than the resonance frequency f0.

The driving frequency can be changed from the starting frequency f_start to the resonant frequency f0 by digital frequency control. Here, the driving frequency can be changed according to the frequency interval f_interval preset by the controller 1500. For example, when the controller 1500 uses a clock source with a clock frequency of 400 MHz for frequency change, the frequency interval can be about 0.04 MHz. In this case, the RF generator 1000 can have a frequency control resolution of about 1%.

The driving frequency can be set to the first driving frequency f1 or the second driving frequency f2 by digital frequency control.

Here, when considering the frequency interval, the first drive frequency f1 and the second drive frequency f2 can be understood as frequencies closest to the resonant frequency f0. In other words, the resonant frequency f0 may exist between the first drive frequency f1 and the second drive frequency f2, and the first drive frequency f1 and the second drive frequency f2 may be separated from each other by the frequency interval.

In addition, here, when the inverter 1300 operates at the first driving frequency f1 or the second driving frequency f2, the voltage applied to the load and the current flowing through the load can meet the same phase identification condition.

Each of the driving frequencies may have a delay time corresponding thereto. For example, the first delay time td1 may correspond to the first driving frequency f1, and the second delay time td2 may correspond to the second driving frequency f2.

Here, when AC power having a corresponding driving frequency is applied to a load, the delay time may refer to the delay time between the delay time of the voltage applied to the load and the delay time of the current flowing through the load.

The delay time may be a value obtained by the phase detector 1510. Alternatively, the resonant frequency f0 may be used to calculate the delay time or a lookup table may be used to obtain the delay time.

According to the above digital frequency control, the RF generator 1000 can adjust the driving frequency of the AC power applied to the load so that the phase difference between the current and voltage of the load is reduced. When the digital frequency control method (S1000) is used, the power loss in the load can be reduced, thereby improving the plasma induction efficiency and reducing the damage to the plasma generating unit 3000.

Digital frequency control is explained above. By quickly setting a specific frequency as a driving frequency, digital frequency control can be implemented with an easy-to-use configuration and a relatively small configuration. However, since the frequency interval is limited in the case of digital frequency control, when the frequency needs to be controlled more finely, the efficiency may be reduced and thus high-resolution frequency control may be required.

Hereinafter, high-resolution frequency control will be described with reference to FIGS. 7 to 10.

FIG. 7 is a diagram related to the structure of an RF generator 1000 for high-resolution frequency control according to an embodiment of the present specification.

Referring to FIG. 7 , the RF generator 1000 may include an inverter 1300, a sensor module 1400, and a controller 1500.

Unless otherwise stated, the contents of the inverter 1300 and the sensor module 1400 described in FIG. 4 can be applied to the inverter 1300 and the sensor module 1400 as is.

The controller 1500 may include a phase detector 1510, a PWM generator 1520, a switching circuit 1530, and a time delay unit 1540. Unless otherwise specified, the contents of the phase detector 1510 and the PWM generator 1520 described in FIG. 4 may be applied to the phase detector 1510 and the PWM generator 1520 as is.

The phase detector 1510 can obtain current phase data and voltage phase data. The phase detector 1510 can obtain current phase data from the sensor module 1400 and voltage phase data from the switch signal.

The phase detector 1510 can obtain the delay time using the current phase data and the voltage phase data, and provide the delay time to at least one of the PWM generator 1520 and the time delay unit 1540. The phase detector 1510 can obtain the delay time at multiple time points.

The PWM generator 1520 can generate a switching signal based on the delay time and provide the switching signal to the inverter 1300. For example, the PWM generator 1520 can set the driving frequency based on the delay time, generate a switching signal so that the inverter 1300 operates at the set driving frequency, and provide the switching signal to the inverter 1300.

The PWM generator 1520 may be electrically connected to the switching circuit 1530. The PWM generator 1520 may provide a switching signal to the inverter 1300 via the switching circuit 1530.

The switching circuit 1530 can be electrically connected to the PWM generator 1520 or the time delay unit 1540, and can be electrically connected to the inverter 1300 and the phase detector 1510. The switching circuit 1530 can change the component to be electrically connected to the inverter 1300 from the PWM generator 1520 to the time delay unit 1540, or from the time delay unit 1540 to the PWM generator 1520.

The time delay unit 1540 can delay the signal input thereto and output the delayed signal. The time delay unit 1540 can delay the signal obtained from the sensor module 1400 and provide the delayed signal to the inverter 1300. Specifically, the time delay unit 1540 can obtain a signal corresponding to the current phase data from the sensor module 1400, delay the signal for a predetermined time, and provide the delayed signal to the first switch S1 to the fourth switch S4 via the switch circuit 1530.

Here, the predetermined time may indicate the extent to which the time delay unit 1540 delays the signal. For example, the predetermined time may refer to an initial delay time set based on the delay time between voltage and current. As another example, the predetermined time may refer to a time obtained by adding or subtracting a time interval t_interval determined according to the characteristics of the RF generator 1000 from a time delayed at a previous time point. In this case, when the RF generator 1000 delays a signal using a clock source having a clock frequency of 400 MHz, the time interval may be set to 2.5 nanoseconds, which is the reciprocal of the clock frequency.

Here, when the time delay unit 1540 is electrically connected to the inverter 1300 via the switch circuit 1530, the initial delay time may indicate the extent to which the time delay unit 1540 delays the input signal. The time delay unit 1540 may obtain the initial delay time from the phase detector 1510. The initial delay time will be described in detail below.

FIG8 is a diagram related to a high-resolution frequency control method (S2000) according to an embodiment of the present specification.

FIG. 9 is a graph related to the driving frequency controlled by high-resolution frequency control according to an embodiment of the present specification.

Referring to FIG. 8 , the high-resolution frequency control method (S2000) may include: controlling the driving frequency using a digital frequency control method (S2100); obtaining an initial delay time (S2200); switching to an analog frequency control method (S2300); applying a delayed signal to the inverter 1300 based on the initial delay time (S2400); obtaining current phase data, voltage phase data, and delay time (S2500); and applying a delayed signal to the inverter 1300 based on the delay time (S2600).

In the following, each operation of the high-resolution frequency control method (S2000) will be described in detail.

The RF generator 1000 may control the driving frequency (S2100) using the digital frequency control method (S1000). The RF generator 1000 may apply AC power having a specific driving frequency to the load using the above-mentioned digital frequency control method (S1000). Specifically, the RF generator 1000 may increase or decrease the driving frequency based on the phase difference between the voltage applied to the load and the current flowing through the load, and provide the AC power having the increased or decreased driving frequency to the load. Referring to FIG. 9 , the driving frequency changed by the RF generator 1000 may be a first driving frequency f1 or a second driving frequency f2 close to the variable resonant frequency f0 of the load.

The RF generator 1000 may obtain an initial delay time (S2200). For example, the RF generator 1000 may obtain a delay time corresponding to a driving frequency close to the resonant frequency f0 of the load as the initial delay time. Specifically, referring again to FIG. 9 , the RF generator 1000 may apply AC power having a first driving frequency f1 to the load according to digital frequency control, and obtain a first delay time td1 corresponding to the first driving frequency f1 as the initial delay time. Alternatively, the RF generator 1000 may apply AC power having a second driving frequency f2 to the load according to digital frequency control, and obtain a second delay time td2 corresponding to the second driving frequency f2 as the initial delay time.

The initial delay time may be obtained by the phase detector 1510 and stored in the memory. Alternatively, the initial delay time may be calculated based on the delay time obtained by the phase detector 1510.

The RF generator 1000 may switch the frequency control method from digital frequency control to analog frequency control (S2300). The RF generator 1000 may switch the frequency control method by changing the component electrically connected to the inverter 1300 from the PWM generator 1520 to the time delay unit 1540 using the switch circuit 1530.

Here, analog frequency control may refer to a frequency control method using a time delay unit 1540, which will be described below. Specifically, when analog frequency control is used, at least one of the phase of the voltage applied to the load and the phase of the current flowing through the load may be delayed or reduced, thereby reducing the phase difference between the voltage and the current.

The RF generator 1000 may apply a delayed signal to the inverter 1300 based on the initial delay time (S2400). The time delay unit 1540 may delay the signal input thereto by the initial delay time and output the delayed signal. Specifically, the time delay unit 1540 may obtain current phase data from the sensor module 1400 and provide the inverter 1300 with a signal obtained by delaying the current phase data by the initial delay time.

By applying a delayed signal to the inverter 1300 based on the initial delay time of the RF generator 1000, more precise frequency control can be implemented and malfunction of the plasma system 100 can be prevented. Specifically, when the RF generator 1000 uses any delay time other than the initial delay time, the RF generator 1000 may provide AC power having a driving frequency far from the resonant frequency f0 to the load, and sufficient power may not be provided inside the plasma generating unit 3000, and thus it may be difficult to form or maintain plasma.

On the other hand, as described above, since the initial delay time corresponds to the delay time of the driving frequency close to the resonant frequency f0, the RF generator 1000 can use the time delay unit 1540 to implement analog frequency control in the area close to the resonant frequency f0.

The RF generator 1000 can obtain current phase data, voltage phase data and delay time (S2500). The phase detector 1510 can obtain current phase data from the sensor module 1400, obtain voltage phase data from the time delay unit 1540, obtain the delay time between voltage and current, and provide the obtained delay time to the time delay unit 1540.

The time delay unit 1540 may apply a delayed signal to the inverter 1300 based on the delay time (S2600). For example, when the obtained delay time does not meet the second in-phase recognition condition, the time delay unit 1540 may delay the current phase data by a time longer or shorter than the initial delay time, and provide the delayed current phase data to the inverter 1300. Specifically, when the obtained delay time is less than the second in-phase recognition condition, the time delay unit 1540 may delay the current phase data by a time shorter than the initial delay time, and provide the delayed current phase data to the inverter 1300. Alternatively, when the obtained delay time is greater than the second in-phase identification condition, the time delay unit 1540 may delay the current phase data by a time greater than the initial delay time and provide the delayed current phase data to the inverter 1300.

Here, the current phase data may refer to a current phase signal. Therefore, when the time delay unit 1540 provides the inverter 1300 with a current phase signal whose phase is delayed or reduced, the phase difference between the voltage applied to the load and the current flowing through the load may be reduced compared to the previous time point.

Here, the second in-phase identification condition may be the same as or different from the first in-phase identification condition used in digital frequency control. The second in-phase identification condition may be set in the same manner as the method of setting the above-mentioned first in-phase identification condition.

The time delay unit 1540 may provide a signal input thereto to the inverter 1300 by delaying the input signal by a preset time interval that is longer or shorter than the delay time at the previous time point. For example, if the current phase signal is delayed by a first time at a first time point, the time delay unit 1540 may delay the current phase signal by a second time obtained by adding the time interval to the first time at a second time point after the first time point, and provide the delayed current phase signal to the inverter 1300. As another example, if the current phase signal is delayed by a first time at a first time point, the time delay unit 1540 may delay the current phase signal by a second time obtained by subtracting the time interval from the first time at a second time point after the first time point, and provide the delayed current phase signal to the inverter 1300.

In this case, the resolution of the frequency control can be determined according to the time interval set in the RF generator 1000. At the same time, when the RF generator 1000 uses the same clock source when implementing digital frequency control and analog frequency control, the resolution of the analog frequency control can be higher than the resolution of the digital frequency control.

At least some of the operations included in the above-mentioned high-resolution frequency control method (S2000) may be omitted. For example, in the high-resolution frequency control method (S2000), the digital frequency control method (S1000) may be omitted, and a lookup table stored in a memory may be used to obtain an initial delay time, and the obtained initial delay time may be used to implement analog frequency control.

The RF generator 1000 can control the inverter 1300 based on the driving frequency set according to the high-resolution frequency control, but it can be detected that the resonant frequency of the load changes while maintaining the plasma, and the inverter 1300 is operated at a driving frequency different from the existing driving frequency by implementing the above-mentioned high-resolution frequency control method (S2000) again.

Referring to FIG. 9 , the driving frequency of the AC power applied to the load according to the high-resolution frequency control can be accurately controlled to be close to the resonant frequency f0 of the load, and the resonant frequency f0 varies with time.

The RF generator 1000 may control the driving frequency to a first driving frequency f1 or a second driving frequency f2 close to the resonant frequency f0 using a digital frequency control method (S1000).

The RF generator 1000 can control the frequency to move from the first driving frequency f1 or the second driving frequency f2 to the resonant frequency f0 by analog frequency control.

Here, the controlled drive frequency can be increased or decreased by an amount corresponding to a specific time interval t_interval.

Here, since the driving frequency is controlled, the delay time between the voltage applied to the load and the current flowing through the load can be gradually reduced. For example, when the frequency is controlled from the first driving frequency f1 to the resonant frequency f0, the delay time between the voltage and the current of the load can be changed to the time interval t_interval from the first delay time td1 to the third delay time td3. In this case, the third delay time td3 may include a value close to 0 nanoseconds or an integer multiple of a cycle compared to the first delay time td1, which is the reciprocal of the driving frequency. That is, the third delay time td3 may indicate that the delay time or phase difference between the voltage and current of the load is relatively reduced.

FIG. 10 is a graph related to changes in the current phase difference and voltage phase difference of a load in high-resolution frequency control according to an embodiment of the present specification.

When plasma is induced in the plasma system 100, the voltage V _RF applied to the load and the current I _RF flowing through the load may not have the same phase.

When there is a delay time or phase difference between the voltage and current of the load, sufficient power is not applied to the plasma generating unit 3000, and thus plasma may not be formed or maintained. In addition, the switch in the inverter 1300 may operate in a state where voltage is applied or current flows, thereby causing damage to the switch.

The RF generator 1000 can be controlled by high-resolution frequency control so that the voltage applied to the load and the current flowing through the load have a phase difference of the first delay time td1. For example, when the RF generator 1000 implements the above-mentioned digital frequency control, the AC power applied to the load can be controlled to have a first driving frequency f1, and the phase of the current flowing through the load can precede the phase of the voltage applied to the load by the first delay time td1.

Referring again to FIG. 10 , when the RF generator 1000 implements the above-mentioned high-resolution frequency control, the phases of the voltage and current of the load can be controlled to be substantially the same. For example, the RF generator 1000 delays the phase signal of the current flowing through the load by a predetermined time (e.g., a time obtained by increasing or decreasing the first delay time td1 by the time interval dt) to provide the delayed phase signal to the inverter 1300, thereby reducing the phase difference between the current and voltage of the load.

As shown in FIG. 10 , when the phase condition that the phase of the current and voltage of the load are substantially the same is met, the plasma generating unit 3000 can be provided with power sufficient to form and maintain plasma. In addition, the switch in the inverter 1300 operates in a state where no voltage is applied (i.e., in a ZVS (zero voltage switching) state) or in a state where very little current flows (i.e., in a state close to a ZCS (zero current switching) state), thereby preventing damage to the switch and improving the durability of the plasma system 100.

Hereinafter, the fine frequency control will be described with reference to FIGS. 11 to 13.

FIG. 11 is a diagram related to the structure of an RF generator 1000 for fine frequency control according to an embodiment of the present specification.

Referring to FIG. 11 , the RF generator 1000 may include an inverter 1300, a sensor module 1400, a controller 1500, and a voltage detector 1600. In the following description, unless otherwise stated, the contents of the components of the RF generator 1000 described in FIG. 4 may be equally applied to the RF generator 1000.

The voltage detector 1600 can sense the electrical properties of the load. The voltage detector 1600 can measure the voltage amplitude of the load in real time or periodically. Specifically, the voltage detector 1600 can measure the voltage of at least a portion of the antenna structure 2000 to obtain voltage data.

Referring again to FIG. 3 , the voltage detector 1600 may be electrically connected to at least one of the first antenna 2100 to the third antenna 2300 to measure the voltage applied to both ends of the antenna or the voltage relative to the ground node. For example, the voltage detector 1600 may measure the voltage applied to both ends of the first antenna 2100 disposed at the innermost side relative to the plasma generating unit 3000, or measure the voltage at a specific point relative to the ground. As another example, the voltage detector 1600 may measure all voltage values of each of the first antenna 2100 to the third antenna 2300.

Here, the voltage data may include a voltage value detected from a time point when the RF generator 1000 operates, or may include a voltage value detected in a specific time period. For example, the voltage data may include a voltage value measured from a time point when the phase difference between the voltage applied to the load and the current flowing through the load is within a range in which the phases of the voltage and the current are considered to be substantially the same.

The voltage detector 1600 may store the measured electrical properties of the load in a memory, or provide the measured electrical properties to the controller 1500. The voltage detector 1600 may provide voltage data measured for at least a portion of the antenna structure 2000 to the PWM generator 1520, or may store the voltage data in a memory.

The controller 1500 can obtain antenna voltage data from the voltage detector 1600. The PWM generator 1520 can obtain voltage data from the voltage detector 1600.

The controller 1500 may use the voltage data to implement fine frequency control. The PWM generator 1520 may generate a switching signal based on the voltage data and provide the switching signal to the inverter 1300 as described below. Specifically, the PWM generator 1520 generates a switching signal with reference to the voltage data so that the frequency of the AC power applied to the load becomes a driving frequency corresponding to the minimum antenna voltage, and provides the switching signal to the inverter 1300.

In the above, it has been mainly explained that the voltage of the load is measured for fine frequency control, but the technical spirit of the present specification is not limited thereto, and the RF generator 1000 can use the current of the load or the amplitude of the power consumed by the load to implement fine frequency control. For example, the RF generator 1000 can use the current or voltage measured at the input or output of the inverter 1300 to calculate the power consumed by the inverter 1300 or the load, and use the calculated power as a standard for fine frequency control.

FIG. 12 is a diagram related to a fine frequency control method (S3000) according to an embodiment of the present specification.

Referring to FIG. 12 , the fine frequency control method (S3000) may include: obtaining a delay time between a current and a voltage (S3100); obtaining voltage data (S3200); controlling a driving frequency using the delay time (S3300); determining an in-phase region identified as in-phase based on the delay time (S3400); selecting a final maintained frequency in the in-phase region based on the voltage data (S3500); and providing a switching signal to the inverter 1300 based on the final maintained frequency (S3600).

In the following, each operation will be explained in detail.

The RF generator 1000 can obtain the delay time between the current and the voltage (S3100). As described elsewhere herein, the phase detector 1510 can obtain the current phase data of the load from the sensor module 1400 and the voltage phase data of the load from the PWM generator 1520 to obtain the delay time between the current and the voltage of the load.

The RF generator 1000 can obtain voltage data (S3200). The voltage detector 1600 can measure the voltage value of at least a portion of the antenna structure 2000 to obtain the voltage data. The RF generator 1000 can store the obtained voltage data in the PWM generator 1520 or the memory.

The obtained voltage data can be stored in association with at least one of the delay time between the current and the voltage and the corresponding driving frequency.

The RF generator 1000 may use the delay time to control the driving frequency (S3300). For example, as described elsewhere herein, the PWM generator 1520 may generate a switching signal based on the delay time and provide the switching signal to the inverter 1300 so that AC power having a frequency closer to the resonant frequency f0 of the load may be applied to the load.

The RF generator 1000 may determine the in-phase region identified as in-phase based on the delay time (S3400). For example, when the obtained delay time satisfies the first in-phase identification condition, the RF generator 1000 may obtain the corresponding driving frequency range as the in-phase region. Specifically, the RF generator 1000 may sense the delay time while continuously reducing the driving frequency, and determine the region from the driving frequency that the detected delay time satisfies the first in-phase identification condition to the driving frequency that the detected delay time does not satisfy the first in-phase identification condition as the in-phase region.

Meanwhile, the in-phase region may refer to a range of delayed time, so that the phase of the voltage and current of the load is identified as being substantially in phase. For example, when the RF generator 1000 uses the above-mentioned high-resolution frequency control method (S2000) to control the driving frequency of the inverter 1300, the in-phase region may be understood as a range in which the time delay unit 1540 delays the current phase signal by a predetermined time. In this case, the RF generator 1000 may further include a switching circuit 1530 and a time delay unit 1540, and each predetermined time may be stored in a memory or the time delay unit 1540 together with the corresponding voltage value.

Meanwhile, in the case where the high-resolution frequency control method (S2000) is used together with the fine frequency control method (S3000), the fine frequency control method (S3000) may be used in at least one of the digital frequency control method and the analog frequency control method. For example, in the case of digital frequency control using only the PWM generator 1520, the fine frequency control method (S3000) may be used in consideration of the voltage of the load. As another example, the fine frequency control method (S3000) may not be used for digital frequency control, and may be used only in the case where the digital frequency control is switched to the analog frequency control by the switching circuit 1530. As another example, the fine frequency control method (S3000) can be used in both digital frequency control and analog frequency control.

The RF generator 1000 may select a final holding frequency in the in-phase region based on the voltage data (S3500). For example, the controller 1500 may select a driving frequency associated with a minimum voltage value in the in-phase region as the final holding frequency. Alternatively, the controller 1500 may select a driving frequency associated with a minimum delay time in the in-phase region as the final holding frequency. At this time, the controller 1500 may store data received from the voltage detector 1600 in all frequency ranges and use the stored data to select the final holding frequency. Alternatively, the controller receives only voltage data in the in-phase region from the voltage detector 1600 and may use the voltage data to select the final maintained frequency.

The controller 1500 may provide a switching signal to the inverter 1300 based on the final maintenance frequency (S3600). For example, the PWM generator 1520 may generate a switching signal so that the frequency of the AC power applied to the load becomes the final maintenance frequency, and provide the switching signal to the inverter 1300. As another example, when the high-resolution frequency control method (S2000) is used, the time delay unit 1540 delays the current phase signal by a predetermined time corresponding to the current phase signal so that the frequency of the AC power applied to the load becomes the final maintenance frequency, and provides the delayed current phase signal to the inverter 1300.

According to the above-mentioned fine frequency control method (S3000), the RF generator 1000 can control the driving frequency using the delay time in the first section, determine the in-phase region using the first in-phase identification condition or the second in-phase identification condition, select the final maintenance frequency based on the voltage data, and apply the AC power having the final maintenance frequency to the load in the second section.

The RF generator 1000 can control the inverter 1300 based on the final maintenance frequency according to the fine frequency control, but the RF generator 1000 can detect that the resonant frequency of the load changes when maintaining plasma, and by implementing the above-mentioned fine frequency control method (S3000) again, the inverter 1300 is operated at a final maintenance frequency different from the existing final maintenance frequency.

FIG. 13 is a graph related to the phase difference between the voltage and current of a load in fine frequency control according to an embodiment of the present specification.

Referring to FIG. 13 , at the plasma induction start time point, the RF generator 1000 operates the inverter 1300 at the start frequency f_start, and after a predetermined time has passed according to the fine frequency control, the RF generator 1000 operates the inverter 1300 at the final maintenance frequency.

As described elsewhere in this document, the starting frequency f_start can be set based on an existing database or arbitrarily.

Referring again to FIG. 13 , the RF generator 1000 may implement fine frequency control to determine an in-phase region including the first driving frequency f1 to the fourth driving frequency f4.

The in-phase region may indicate a phase difference range in which plasma is easily formed or maintained. For example, the in-phase region may include a range of -5 nanoseconds to 20 nanoseconds, or may be set to include some cycles within the range of -5 nanoseconds to 20 nanoseconds.

The first driving frequency f1 to the fourth driving frequency f4 may satisfy the first in-phase identification condition or the second in-phase identification condition. For example, when AC power having the first driving frequency f1 to the fourth driving frequency f4 is applied to the load, the phase difference between the voltage and the current of the load may satisfy the first in-phase identification condition or the second in-phase identification condition.

The RF generator 1000 may obtain voltage data including voltage values corresponding to the first driving frequency f1 to the fourth driving frequency f4. To this end, the RF generator 1000 may store a delay time or a voltage value associated with the corresponding driving frequency, the delay time or the voltage value being measured when the inverter 1300 is driven at the first driving frequency f1 to the fourth driving frequency f4.

The RF generator 1000 may select a final maintenance frequency from the first driving frequency f1 to the fourth driving frequency f4. Referring back to FIG. 13 , since the voltage value associated with the second driving frequency f2 is the lowest, the RF generator 1000 selects the second driving frequency f2 as the final maintenance frequency and operates the inverter 1300 at the final maintenance frequency. At the same time, the RF generator 1000 may select the third driving frequency f3 having the smallest delay time as the final maintenance frequency and operate the inverter 1300 at the final maintenance frequency.

Since the above-mentioned fine frequency control method (S3000) is used in the plasma system 100, frequency control in which load characteristics are more taken into consideration can be implemented, and thus, plasma formation and maintenance efficiency can be improved, and damage to the plasma generating unit 3000 caused by application of a high voltage can be prevented.

In the following, the signal transmission method with noise immunity will be described with reference to FIG. 14 and FIG. 15 .

The plasma system 100 according to an embodiment of the present specification can continuously track the resonant frequency f0 of the load to induce and maintain plasma, and the RF generator 1000 can control the driving frequency of the inverter 1300. At this time, due to the nature of the plasma that is sensitive to the power or energy provided, the RF generator 1000 is required to quickly and stably control the inverter 1300. In particular, when the transmission line used to transmit the switching signal from the PWM generator 1520 to the inverter 1300 is relatively long and is set near the high-frequency or high-voltage output source, the switching signal may be exposed to switching noise. Therefore, a signal transmission method that is insensitive to switching noise is required.

FIG. 14 is a diagram related to a method for transmitting and receiving a switching signal using an amplifier and an attenuator according to an embodiment of the present specification.

Referring to FIG. 14 , the PWM generator 1520 may provide a switching signal to the inverter 1300 via the voltage amplifier 1710 and the voltage attenuator 1720 . The contents of the PWM generator 1520 and the inverter 1300 described in other parts of this specification are equally applicable to the PWM generator 1520 and the inverter 1300 , and therefore, repeated description thereof will be omitted.

The PWM generator 1520 can transmit the switching signal to the voltage amplifier 1710.

Here, the switch signal may include a specific voltage value indicating the on/off of the switch in the inverter 1300. For example, the switch signal may include 5 volts (V) indicating on and 0 volts indicating off.

Meanwhile, the inverter 1300 receiving the switching signal may have a switch critical voltage. The switch critical voltage may be used as a reference for turning on or off the switch in the inverter 1300. For example, when the switching signal includes 5 volts and 0 volts, the switch in the inverter 1300 may have a critical voltage between about 2 volts and 3 volts, and the switch may be turned off when a signal lower than the critical voltage is received, and the switch may be turned on when a signal higher than the critical voltage is received. At this time, when the switching noise is applied to the switching signal and thus the switching signal is higher or lower than the critical voltage, the inverter 1300 may fail.

The voltage amplifier 1710 can be electrically connected to the PWM generator 1520 and obtain a switching signal from the PWM generator 1520.

The voltage amplifier 1710 can amplify the obtained switching signal. For example, the voltage amplifier 1710 can amplify a 5-volt switching signal into a 12-volt switching signal.

The voltage amplifier 1710 can be electrically connected to the voltage attenuator 1720. Specifically, the voltage amplifier 1710 can be electrically connected to the voltage attenuator 1720 via a conductive wire, and switching noise can be generated according to the length and layout of the conductive wire.

The voltage attenuator 1720 can receive the amplified switching signal from the voltage amplifier 1710.

The voltage attenuator 1720 can attenuate the received switching signal. For example, the voltage attenuator 1720 can attenuate the amplified 12 volt switching signal to a 5 volt switching signal.

The voltage attenuator 1720 may have an attenuator threshold voltage. The attenuator threshold voltage may be a reference for determining whether the switch signal received by the voltage attenuator 1720 is output as a signal indicating connection or a signal indicating disconnection. The attenuator threshold voltage may be set so that the threshold voltage is exceeded or not exceeded even when switching noise is applied to the switching signal. For example, when the voltage attenuator 1720 receives a switching signal amplified to 12 volts, switching noise is applied to the switching signal, and the amplitude of the noise superimposed on the switching signal increases or decreases by about 3 volts, and the attenuator threshold voltage can be set between 3 volts and 9 volts.

The attenuator threshold voltage may be set higher than the switch threshold voltage. Therefore, the voltage attenuator 1720 may receive a switching signal to which noise is applied, and provide the switching signal to the inverter 1300 after removing the noise.

FIG. 15 is a diagram related to a method for transmitting and receiving a switching signal using an optical converter according to an embodiment of the present specification.

Referring to FIG. 15 , the PWM generator 1520 may provide a switching signal to the inverter 1300 via the voltage-to-optical converter 1730 and the optical-to-voltage converter 1740. The contents of the PWM generator 1520 and the inverter 1300 described in FIG. 14 are equally applicable to the PWM generator 1520 and the inverter 1300, and thus repeated description thereof will be omitted.

The voltage-to-optical converter 1730 may receive a switching signal from the PWM generator 1520, convert the switching signal into an optical signal, and provide the optical signal to the optical-to-voltage converter 1740.

The optical-to-voltage converter 1740 can receive the optical signal from the voltage-to-optical converter 1730, convert the optical signal into a voltage signal corresponding to the switch signal, and provide the voltage signal to the inverter 1300.

The voltage-to-optical converter 1730 and the optical-to-voltage converter 1740 can be connected by optical fibers and can thus transmit and receive optical signals by optical communication. Such optical communication can substantially block switching noise.

Meanwhile, above, the method of stably transmitting and receiving signals in the method in which the RF generator 1000 controls the inverter 1300 by the PWM generator 1520 has been mainly described, but the technical spirit of the present specification is not limited thereto. As an example, the above-mentioned signal transmission/reception method can be similarly applied to the frequency control method using the PWM generator 1520 and the time delay unit 1540 described in other parts of the present specification. For example, the voltage amplifier 1710 described in FIG. 14 and the voltage-to-optical converter 1730 described in FIG. 15 can be connected to at least one of the PWM generator 1520, the time delay unit 1540, and the switching circuit 1530.

The RF generator 1000 can control the inverter 1300 by the signal transmission and reception method described in FIG. 14 and FIG. 15. By using such a signal transmission and reception method, the RF generator 1000 can minimize the influence of switching noise, and thus can prevent damage to the RF generator 1000 and can achieve stable frequency control.

The method according to the embodiment can be implemented in the form of program commands, which are executed by various computer components and can be recorded in a computer-readable medium. The computer-readable medium can include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded in the computer-readable medium can be specially designed and configured for the embodiment, or can be available to technicians in the field of computer software. Examples of computer-readable recording media may include magnetic media (e.g., hard disks, floppy disks, and magnetic tapes), optical media (e.g., compact disc read-only memory (CD-ROM) and digital versatile disc (DVD)), magneto-optical media (e.g., floptical disks), and hardware units (e.g., read-only memory (ROM), random access memory (RAM), flash memory, etc.) that are intentionally formed to store and execute program instructions. Examples of program instructions include machine language codes generated by a compiler and high-level language codes that can be executed by a computer using an interpreter, etc. The above-mentioned hardware devices may be configured to operate as one or more software modules to implement the operation of the embodiment, and vice versa.

Although the embodiments of the present disclosure have been described with reference to limited embodiments and drawings, those skilled in the art may make various modifications and variations based on the above description. For example, although the embodiments of the present disclosure are implemented in a different order than described, and/or components (e.g., systems, structures, devices, circuits, etc.) are combined or assembled in a different manner than described, or other components or their equivalents are used to replace or substitute the components, the desired results can also be achieved.

Therefore, other embodiments, other embodiments and equivalents of the attached patent application scope may be included within the scope of the attached patent application scope.

100: Plasma system

1000: Radio frequency (RF) generator

2000: Antenna structure

3000: Plasma generation unit

Claims (27)

A device for controlling a variable harmonic frequency of a load and providing power to the load, the device comprising: an inverter configured to convert direct current power into a first alternating current power having a first driving frequency and apply the first alternating current power to the load; a sensor configured to obtain a first delay time and a second delay time, wherein the first delay time represents a phase difference between a current and a voltage of the load at a first time point, and the second delay time represents a phase difference between a current and a voltage of the load at a second time point; a pulse width modulation generator configured to provide a first switching frequency to the inverter based on the first delay time. A first switching signal, wherein the first switching signal corresponds to a second driving frequency, the second driving frequency differs from the first driving frequency by a predetermined frequency, and the predetermined frequency is determined based on the first delay time for the load; and a time delay unit, configured to provide a second switching signal to the inverter, wherein the second switching signal is determined based on the second delay time and corresponds to a third AC power, wherein for the load, the third AC power differs from the second AC power by a predetermined phase, so that the phase difference between the current and the voltage of the load is reduced compared to the case where the second AC power is applied to the load. A device as described in claim 1, wherein the predetermined frequency is greater than the frequency difference between the second driving frequency and the third driving frequency corresponding to the third AC power. The device as claimed in claim 1, wherein the time delay unit is configured to receive a phase signal of the load and delay the phase signal by the predetermined phase to obtain the second switching signal, and is configured to output the obtained second switching signal, and wherein the phase signal of the load indicates the phase of the current of the load. A device as described in claim 3, wherein the predetermined phase includes a phase corresponding to the second delay time. The device as described in claim 1 further includes: a switching circuit configured to electrically connect at least one of the pulse width modulation generator and the time delay unit to the inverter. The device as described in claim 5, wherein the switching circuit is configured to switch the pulse width modulation generator connected to the inverter by the time delay unit when the second delay time meets a predetermined condition. The device as described in claim 1 further includes: a clock source having a predetermined clock frequency, wherein the predetermined frequency is obtained by dividing the predetermined clock frequency by an integer, and wherein the predetermined phase is an integer multiple of the reciprocal value of the predetermined clock frequency. The device as described in claim 1 further comprises: a phase sensing unit configured to periodically obtain and provide a phase signal of the load, wherein the sensor is configured to periodically obtain a delay time and provide the delay time to the time delay unit, and wherein the time delay unit is configured to provide a switching signal to the inverter, wherein the switching signal is obtained by delaying the phase signal based on the delay time. The device as described in claim 5 further includes: an amplifier electrically connected to the switching circuit and configured to amplify the signal; and an attenuator connected to the inverter and configured to attenuate the signal, wherein the critical voltage of the attenuator is greater than the critical voltage of the inverter to prevent noise. The device as described in claim 5 further comprises: a first converter electrically connected to the switching circuit and configured to convert the electrical signal into an optical signal; and a second converter electrically connected to the inverter and configured to convert the optical signal into an electrical signal, wherein the switching circuit is configured to provide the first switching signal or the second switching signal to the inverter via the first converter and the second converter. A method for controlling a variable harmonic frequency of a load and providing power to the load, the method comprising: applying a first AC power having a first driving frequency to the load using an inverter; obtaining a first delay time representing a phase difference between a current and a voltage of the load at a first time point using a sensor; applying a second AC power having a second driving frequency to the load, wherein the second driving frequency differs from the first driving frequency by a predetermined frequency, and the predetermined frequency is Determined based on the first delay time; using a sensor to obtain a second delay time representing the phase difference between the current and voltage of the load at a second time point; and applying a third AC power to the load, wherein the third AC power differs from the second AC power by a predetermined phase, and the predetermined phase is determined based on the second delay time, so that the phase difference between the current and voltage of the load is reduced compared to the case where the second AC power is applied to the load. The method of claim 11 further includes: using a pulse width modulation generator to provide the inverter with a first switching signal corresponding to the first driving frequency; using the pulse width modulation generator to provide the inverter with a second switching signal corresponding to the second driving frequency; and using a time delay unit to provide the inverter with a third switching signal corresponding to the third AC power, wherein the third switching signal is obtained by delaying the phase signal of the load. A method as described in claim 12, wherein the phase signal is a current phase signal of the load before an alternating current power having a third driving frequency is applied to the load. A device for controlling a variable harmonic frequency of a load and providing power to the load, the device comprising: an inverter configured to convert direct current power into alternating current power and provide the alternating current power to the load; a phase detector configured to detect a delay time representing a phase difference between a current and a voltage of the load, wherein the delay time comprises a first delay time at a first time point, a second delay time at a second time point, and a third delay time at a third time point; a pulse width modulation generator configured to provide a switching signal to the inverter, wherein the switching signal corresponds to a driving frequency set based on the first delay time obtained by the phase detector; a time A delay unit is configured to obtain the third delay time from the phase detector, obtain a current phase signal of the current of the load, delay the current phase signal by a predetermined time based on the third delay time, and provide the delayed current phase signal to the inverter; and a switch circuit is configured to electrically connect one of the pulse width modulation generator and the time delay unit to the inverter, and when the second delay time obtained by the phase detector meets a predetermined condition, the time delay unit is electrically connected to the inverter so that the element connected to the inverter is switched from the pulse width modulation generator to the time delay unit. The device as claimed in claim 14, wherein the PWM generator is configured to provide the switching signal so that the frequency of the AC power applied to the load changes from the first driving frequency to the second driving frequency, wherein the time delay unit is configured to delay the current phase signal so that the frequency of the AC power applied to the load changes from the third driving frequency to the fourth driving frequency, and is configured to provide the delayed current phase signal to the inverter, wherein the difference between the first driving frequency and the second driving frequency is greater than the difference between the third driving frequency and the fourth driving frequency. The device as claimed in claim 14, wherein the pulse width modulation generator is configured to provide the switching signal so that the frequency of the AC power applied to the load changes from the first driving frequency to the second driving frequency, wherein the time delay unit is configured to delay the current phase signal so that the frequency of the AC power applied to the load changes from the second driving frequency to the third driving frequency, and is configured to provide the delayed current phase signal to the inverter, wherein the difference between the first driving frequency and the second driving frequency is greater than the difference between the second driving frequency and the third driving frequency. A device as claimed in claim 14, wherein the predetermined condition is set at least within a range between -5 nanoseconds and 20 nanoseconds. A method for controlling a variable resonant frequency of a load and providing power to the load, the method comprising: applying AC power having a specific frequency to the load using an inverter; obtaining a delay time representing a phase difference between a current and a voltage of the load using a first sensor; obtaining voltage data representing a voltage of at least a portion of the load using a second sensor; applying AC power having a driving frequency set based on the delay time to the load in a first section using the inverter; and applying AC power having a driving frequency set based on the voltage data to the load in a second section using the inverter. The method of claim 18 further includes: using the first sensor to determine a frequency range based on a first delay time and a second delay time obtained in the first section; selecting a final maintenance frequency within the frequency range based on the voltage data; and using the inverter to apply AC power having the final maintenance frequency to the load, wherein the first delay time and the second delay time meet predetermined conditions. A method as described in claim 19, wherein the frequency range includes at least a first driving frequency and a second driving frequency, wherein the voltage data includes at least a first voltage and a second voltage, wherein the first voltage is obtained when an AC power having the first driving frequency is applied to the load, and the second voltage is obtained when an AC power having the second driving frequency is applied to the load, and wherein when the second voltage is less than the first voltage, the second driving frequency is selected as the final maintaining frequency. A method as described in claim 18, wherein the phase difference between the current and the voltage of the load in the second section satisfies a predetermined condition. A method as claimed in claim 19 or 21, wherein the predetermined condition is set at least within a range between -5 nanoseconds and 20 nanoseconds. A method as described in claim 18, wherein the load comprises an antenna structure, the antenna structure comprises a first antenna having a first radius of curvature and a second antenna having a second radius of curvature, the second radius of curvature being larger than the first radius of curvature, and wherein the voltage data is obtained by measuring the voltage of the first antenna using the second sensor. A method as described in claim 18, wherein the load comprises an antenna structure, the antenna structure comprises a first antenna having a first radius of curvature and a second antenna having a second radius of curvature, the second radius of curvature being larger than the first radius of curvature, and wherein the voltage data is obtained by measuring the voltage of the first antenna and the voltage of the second antenna using the second sensor. A device for controlling a variable harmonic frequency of a load and providing power to the load, the device comprising: an inverter configured to convert direct current power into alternating current power and provide the alternating current power to the load; a phase detector configured to detect a delay time representing a phase difference between a current and a voltage of the load, wherein the delay time comprises a first delay time at a first time point, a second delay time at a second time point, and a third delay time at a third time point; a voltage detector configured to detect a voltage of the load at a first time point and a voltage at a second time point, and obtain a voltage including a first delay time and a second delay time. The invention relates to a first voltage related to a first delay time and a second voltage related to the second delay time; and a pulse width modulation generator configured to provide a switching signal corresponding to a driving frequency set based on the delay time obtained by the phase detector to the inverter, wherein the pulse width modulation generator is configured to provide a switching signal corresponding to a first driving frequency to the inverter when the first voltage is less than the second voltage, wherein the first driving frequency is set based on the first delay time at a third time point later than the first time point and the second time point. The device as described in claim 25 further includes: an amplifier electrically connected to the pulse width modulation generator and configured to amplify the signal; and an attenuator electrically connected to the inverter and configured to attenuate the signal, wherein the critical voltage of the attenuator is greater than the critical voltage of the inverter to prevent noise. The device as described in claim 25 further includes: a first converter electrically connected to the pulse width modulation generator and configured to convert the electrical signal into an optical signal; and a second converter electrically connected to the inverter and configured to convert the optical signal into an electrical signal, wherein the pulse width modulation generator is configured to provide the first switching signal or the second switching signal to the inverter via the first converter and the second converter.

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