KR20230073918A - Auto frequency tuning apparatus using impedance table, plasma power apparatus including it and auto frequency tuning mehtod - Google Patents

Abstract

An automatic frequency adjusting device according to the present invention includes an impedance calculator for calculating and outputting complex impedances from forward power and reverse power presented as complex numbers; an impedance frequency table for matching and storing an optimal switching frequency for each impedance and outputting a mapping switching frequency corresponding to the impedance of the complex number output from the impedance calculation unit; an automatic frequency adjusting unit outputting a switching frequency variation from forward power and reverse power; a switching frequency adder for adding the mapping switching frequency, the change in switching frequency, and the current switching frequency and outputting the sum; and a determining unit configured to determine the current switching frequency as an optimal switching frequency and store the determined current switching frequency in the impedance frequency table when reverse power is less than a predetermined power level when operating at the current switching frequency.

Description

Automatic frequency adjustment device using impedance frequency table, plasma power device including same, and automatic frequency adjustment method

The present invention relates to a plasma power device, and more particularly, to a device and method for reducing reverse power by performing automatic frequency adjustment using an impedance frequency table in a plasma power device.

Plasma etching is frequently used in semiconductor manufacturing processes. In plasma etching, ions are accelerated by an electric field to etch an exposed surface on a substrate. The electric field is generated according to the high frequency signals generated by the high frequency generator of the high frequency power system. The high-frequency signals generated by the high-frequency generator must be precisely controlled to efficiently perform plasma etching.

The high frequency power system may include a high frequency generator, an impedance matcher, and a plasma chamber. The high frequency signal is used to drive loads to manufacture various components such as integrated circuits (ICs), solar panels, compact discs (CDs), and/or DVDs.

The high frequency signal is received by the impedance matcher. The impedance matcher matches the input impedance of the impedance matcher to the characteristic impedance of a transmission line between the high frequency generator and the impedance matcher. Impedance matching helps maximize the amount of power from the impedance matcher applied to the resonant network in the forward direction towards the plasma chamber ("forward power") and minimizes the amount of power reflected from the impedance matcher to the high frequency generator ("reverse power"). help to do When the input impedance of the impedance matcher matches the characteristic impedance of the transmission line, forward power output from the high frequency generator to the plasma chamber can be maximized and reverse power can be minimized.

In supplying high-frequency power, there are generally two methods of applying a high-frequency signal to a load. First, the traditional method is to apply a continuous wave signal to the load. In CW mode, the CW signal is generally a sine wave that the power supply continuously outputs to the load. In the continuous wave scheme, the high-frequency signal assumes a sinusoidal wave output, and the amplitude and/or frequency of the sinusoidal wave can be varied to change the output power applied to the load.

Another method of applying a high frequency signal to a load is a pulsed high frequency signal. In the pulse mode of operation, a high-frequency sinusoidal signal is modulated by a modulating signal to define an envelope for the modulated sinusoidal signal. In a conventional pulse modulation method, a high-frequency sinusoidal signal is typically output with a constant frequency and amplitude. The power delivered to the load is changed by changing the modulation signal, not by changing the sinusoidal or high-frequency signal.

In a typical high-frequency power supply unit configuration, output power applied to a load is determined by measuring forward power and reflected power of a high-frequency signal applied to the load or by using a sensor that measures voltage and current. One set of these signals is analyzed in a common feedback loop. This analysis usually determines the power value used to adjust the output of the high frequency power supply to change the power applied to the load. In a high-frequency power delivery system where the load is a plasma chamber, a change in load impedance results in a correspondingly variable power applied to the load because the applied power is in part a function of the load impedance.

In addition, the transition from a continuous wave high frequency power delivery system to a pulsed high frequency power delivery system presents additional challenges. In a typical plasma system, the power dissipated in the plasma depends on the impedance of the plasma. When the impedance changes on the time scale of high frequency pulses (e.g., in the range of 1 kHz - 10 kHz), the sensors and actuators within the impedance matcher and the high frequency generator respond on similar time scales to avoid turning off the plasma between pulses. It should provide optimal power coupling to the plasma load. Also, the time response of the impedance is plasma dependent and varies with factors such as chemical, pressure and power combinations. In addition, various parasitic elements outside the plasma, such as resistive losses in a high-frequency coupling antenna or matching system, exhibit a time-varying power coupling efficiency during a pulse period, because the parasitic elements are connected in series with a time-varying impedance load. This is because it is a constant consumption impedance. Additionally, since transmit and reflective power sensors and high frequency generators are typically calibrated for matched terminations, power compensation due to impedance mismatch can contribute to increased variability in power delivery.

In addition, it is important to achieve process synchronization between predicting the corresponding position of the impedance actuator in the impedance matcher and measuring the frequency to minimize the effects of impedance transients. In addition, it becomes more difficult to realize process reproducibility and half speed when achieving the target frequency.

In current high frequency power generation systems, in order to achieve impedance matching between the high frequency power generator and the load, the frequency of the high frequency signal may be adjusted around a selected target frequency or center frequency within a preset range. This frequency-based impedance tuning is called radio frequency tuning (RFT). In some RFT configurations, the frequency of the high-frequency signal may be tuned towards the limits of a predefined range.

Korean Patent Publication No. 10-2018-0031789 Supervisory control of radio frequency impedance tuning

The present invention provides an automatic frequency adjustment device using an impedance frequency table capable of performing automatic frequency adjustment of a matching frequency using the impedance frequency table to minimize reflected power, a plasma power device including the same, and an automatic frequency adjustment method. has a purpose

The problems of the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

An automatic frequency adjusting device according to the present invention includes an impedance calculator for calculating and outputting complex impedances from forward power and reverse power presented as complex numbers; an impedance frequency table for matching and storing an optimal switching frequency for each impedance and outputting a mapping switching frequency corresponding to the impedance of the complex number output from the impedance calculation unit; an automatic frequency adjusting unit outputting a switching frequency variation from forward power and reverse power; a switching frequency adder for outputting a switching frequency by adding the mapping switching frequency and the switching frequency variation; and a determination unit configured to determine the switching frequency as an optimal switching frequency and store the determined switching frequency in the impedance frequency table when reverse power is equal to or less than a predetermined power level when operating at the switching frequency.

Preferably, a switching frequency variation limiter for limiting upper and lower limit values for the switching frequency variation; and a switching frequency limiter limiting upper and lower limits of the current switching frequency.

In addition, a plasma power device according to one aspect of the present invention includes a high-frequency power amplifying unit that is controlled by an amplification control signal to amplify a DC voltage of a predetermined level to generate a pulse-wave high-frequency signal; an impedance matcher controlled by a matching frequency control signal to match an impedance between the high frequency power amplifier and a load to a predetermined matching frequency; an RF sensor configured to detect forward and reverse electrical signals between the high frequency power amplifier and the impedance matcher and output an electrical detection signal; and a controller generating the amplification control signal and the matching frequency control signal using a control signal applied from the outside and an electrical detection signal output from the RF sensor, wherein the controller includes the automatic frequency adjustment device of claim 1 do.

In addition, in a plasma power device according to another aspect of the present invention, first and second high frequency power amplifying modules connected in parallel amplify the smoothing voltage to generate first and second high frequency power signals of pulse waveforms. a high-frequency power supply including an amplification unit; an RF sensor disposed between the high-frequency power source and the RF load and outputting an electrical detection signal by detecting an electrical signal; and a controller outputting the high frequency power supply control signal using a control signal applied from the outside and an electrical detection signal output from the RF sensor, wherein the controller includes the automatic frequency adjusting device of claim 1 .

In addition, a plasma power device according to another aspect of the present invention includes a DC/DC converter that converts a rectified voltage into a stable DC voltage according to a converter control signal; a linear DC voltage regulator that amplifies voltage and current of a predetermined level using the DC voltage output from the DC/DC converter controlled by the regulator control signal to generate a pulse-type variable DC voltage required for pulse mode operation; first and second high frequency power amplifiers generating pulsed high frequency power signals by amplifying the variable direct current voltage output from the linear direct current voltage regulator; and a controller outputting the converter control signal and the regulator control signal, wherein the controller includes the automatic frequency adjusting device of claim 1 .

In addition, the automatic frequency adjustment method of the present invention includes an impedance calculation step of calculating an impedance of a complex number from forward power and reverse power presented as complex numbers; matching and storing an optimal switching frequency for each impedance, and outputting a mapping switching frequency corresponding to the impedance of the complex number output from the impedance calculation unit; outputting a switching frequency variation from forward power and reverse power; outputting a switching frequency by adding the mapping switching frequency and the switching frequency variation; and determining the switching frequency as an optimal switching frequency and storing the switching frequency in the impedance frequency table when the reverse power is equal to or less than a predetermined power level when operating at the switching frequency.

Preferably, limiting upper and lower limit values for the switching frequency variation; and limiting upper and lower limit values for the switching frequency.

Preferably, the impedance calculation step is characterized in that the reflection coefficient of a complex number is calculated using the following equation.

은 반사계수, Z_L은 부하 임피던스, Z₀은 특성 임피던스임.here,

is the reflection coefficient, Z _L is the load impedance, and Z ₀ is the characteristic impedance.

Preferably, the impedance calculation step is characterized in that the impedance of the complex number is calculated using the following equation.

Preferably, the step of outputting the switching frequency variation is characterized by outputting the switching frequency variation using the following equation.

는 반사계수 이득,

는 자동 주파수 조정부 이득, dP_R은 현재 역방향 전력과 직전 역방향 전력의 편차임.Here, fs,offset is the switching frequency offset value,

is the reflection coefficient gain,

is the automatic frequency adjuster gain, and dP _R is the difference between the current reverse power and the previous reverse power.

According to the present invention, the automatic frequency adjustment function can be performed at high speed by selecting a matching frequency using an impedance frequency table to minimize reflected power.

1 is an overall block diagram of a plasma power device in which an automatic frequency adjusting device according to an embodiment of the present invention is implemented;
2 is a specific block diagram of an automatic frequency adjusting device according to an embodiment of the present invention;
3 is an overall block diagram of a plasma power device in which an automatic frequency adjustment device is implemented according to another embodiment of the present invention, and
4 is an overall block diagram of a plasma power device in which an automatic frequency adjusting device according to another embodiment of the present invention is implemented.

Additional objects, features and advantages of the present invention may be more clearly understood from the following detailed description and accompanying drawings.

Prior to the detailed description of the present invention, the present invention may make various changes and may have various embodiments, and the examples described below and shown in the drawings are not intended to limit the present invention to specific embodiments. No, it should be understood to include all changes, equivalents or substitutes included in the spirit and scope of the present invention.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "include" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

In addition, terms such as "...unit", "...unit", and "...module" described in the specification mean a unit that processes at least one function or operation, which is hardware, software, or hardware and It can be implemented as a combination of software.

In addition, in the description with reference to the accompanying drawings, the same reference numerals are given to the same components regardless of reference numerals, and overlapping descriptions thereof will be omitted. In describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

1 is an overall block diagram of a plasma power device in which an automatic frequency adjusting device according to an embodiment of the present invention is implemented.

A plasma power device according to an embodiment of the present invention includes a DC/DC converter 110, a high frequency power amplifier 120, an RF sensor 130, an impedance matcher 140, a controller 150, and a plasma load 160. , and includes a storage unit 170.

The DC/DC converter 115 is controlled by the voltage control signal Vcon output from the controller 150 and converts the applied first DC voltage into a second DC voltage. Here, the second DC voltage may be voltages of various levels.

The high frequency power amplifier 120 amplifies the second DC voltage output from the DC-DC converter 110 to generate a pulse wave high frequency signal. According to the present invention, instead of measuring the output frequency of the high frequency power amplifier 120, the output frequency can be changed by controlling an electrical signal through an internal DDS (Direct Digital Synthesizer, not shown).

The RF sensor 130 is disposed between the high frequency power amplifying unit 120 and the impedance matcher 140, detects forward and reverse electrical signals, and outputs an electrical detection signal. Here, the electrical detection signal is a detection current value (Is), a detection voltage value (Vs), forward power (P _F ) supplied from the high frequency power amplifier 120 to the load 160 (plasma chamber), and the load 160 It may be at least one or more of the reverse power (P _R ) reflected from the high frequency power amplifying unit 120.

The impedance matcher 140 is coupled between the high frequency power amplifying unit 120 and the load 160, and is controlled by the matching frequency control signal Smat output from the controller 150, so that the high frequency power amplifying unit 120 and the load ( 160) is matched with a predetermined matching frequency.

The controller 150 executes a forward power control algorithm using a control signal Scon applied from the outside and an electrical detection signal output from the RF sensor 130 to generate a voltage control signal Vcon and an amplification control signal Pcon. Outputs , calculates the load impedance using the forward power (P _F ) and the reverse power (P _R ), and uses the calculated load impedance to convert the switching frequency from the impedance frequency table such as Table 1 stored in the storage unit 170. (fs) can be selected.

When the switching frequency is 13.56 MHz, the real part of the impedance is 50 ohms and the imaginary part is 0 ohm. For example, as shown in Table 1, if the real part of the impedance is 48 ohms and the imaginary part is -2 ohms, the switching frequency must be 14.23 MHz. If the real part of the impedance is 52 ohms and the imaginary part is 2 ohms, the switching frequency must be 12.88 MHz. . That is, when the load impedance changes, it is necessary to automatically and quickly adjust the switching frequency to reflect this.

2 is a specific block diagram of an automatic frequency adjusting device according to an embodiment of the present invention.

An automatic frequency adjustment device according to an embodiment of the present invention includes an impedance calculation unit 210, an impedance frequency table 220, an automatic frequency adjustment unit 230, a switching frequency variation separator 240, an adder 250, a switching A frequency limiter 260 and a determination unit 270 are included.

The impedance calculator 210 may calculate and extract the load impedance of a complex number using Equations 1 and 2.

Specifically, the impedance calculator 210 may obtain the reflection coefficient of a complex number from forward power (P _F ) and reverse power (P _R ) presented as complex numbers using Equation 1.

은 반사계수, Z_L은 부하 임피던스, Z₀은 특성 임피던스임.here,

is the reflection coefficient, Z _L is the load impedance, and Z ₀ is the characteristic impedance.

Thereafter, the impedance calculator 210 may obtain a complex load impedance from the complex reflection coefficient using Equation 2.

The impedance frequency table 220 is a table storing optimal switching frequencies for each impedance (see Table 1), and the mapping switching frequency (fs,comp) mapped by receiving the complex number impedance calculated by the impedance calculation unit 210 and the optimal switching frequency fs output from the decision unit 270 is stored in the corresponding cell.

)을 출력한다. _The automatic frequency adjusting unit 230 calculates the switching frequency _variation (

) is output.

는 반사계수 이득,

는 자동 주파수 조정부 이득, dP_R은 현재 역방향 전력과 직전 역방향 전력의 편차임.Here, fs,offset is the switching frequency offset value,

is the reflection coefficient gain,

is the automatic frequency adjuster gain, and dP _R is the difference between the current reverse power and the previous reverse power.

)에 대하여 하한치(

)와 상한치(

)를 제한하여 제한된 스위칭 주파수 변동분(

)을 출력한다.The switching frequency variation limiter 240 is the switching frequency variation (

) for the lower limit (

) and the upper limit (

) by limiting the limited switching frequency variation (

) is output.

)를 가산하여 스위칭 주파수(fs)를 출력한다.The adder 250 calculates the mapping switching frequency (fs,comp) and the limited switching frequency variation (

) is added to output the switching frequency (fs).

The switching frequency limiter 260 outputs the limited switching frequency fs,lim by limiting the lower limit value fs,min and the upper limit value fs,max with respect to the switching frequency fs output from the adder 250.

The determiner 270 determines the limited switching frequency (fs,lim) as an optimal frequency when the reverse power ( _PR ) at the limited switching frequency (fs,lim) is less than or equal to a predetermined power level, and determines the limited switching frequency (fs,lim) in the impedance frequency table. fs,lim) is determined as the optimal frequency and stored in the impedance frequency table. On the other hand, if the reverse power (P _R ) exceeds a predetermined power level at the limited switching frequency (fs, lim), the limited switching frequency (fs, lim) is determined to be a non-optimal frequency.

3 is an overall block diagram of a plasma power device in which an automatic frequency adjusting device according to another embodiment of the present invention is implemented.

A high-frequency pulse power supply device according to an embodiment of the present invention includes a three-phase power supply 300, a rectifier 305, a DC / DC converter 310, a linear DC voltage regulator 315, a high-frequency power amplifier 320, a resonance It includes a filter 325, an input sensor 330, a variable matching network 335, an output sensor 340, a controller 345, and a storage unit 350.

The rectifier 305 rectifies the applied three-phase voltage into a rectified voltage and outputs the rectified voltage. Here, reference numeral Srec is a power factor control signal applied from the controller 345 .

The DC/DC converter 310 adjusts the duty ratio of the rectified voltage output from the rectifier 305 and converts the output DC voltage level to reach a set value within a predetermined time. Specifically, the rectified voltage output from the rectifier 305 according to the converter control signal (S _DC ) output from the controller 345 is converted into a pulse-type variable DC voltage required in a semiconductor process (eg, an ALD process) and output. do.

That is, the DC/DC converter 310 is controlled by the converter control signal S _DC output from the controller 345 to control the magnitude of the DC input voltage supplied to the input of the high frequency power amplifier 320 .

However, the DC/DC converter 310 is composed of an inductor, a capacitor, and a switch and a diode that control the inductor, so that energy is stored in the inductor or energy stored in the inductor is connected between the inductor and a voltage source. Repeat the process of discharging to the load. This causes the transient characteristics of the DC input voltage supplied to the high frequency power amplifier 320 by the DC/DC converter 310 to appear. Thus, when the linear DC voltage regulator 315 operates in the pulsing operation mode, the high frequency power amplifier 320 improves the transient characteristic delay of the DC/DC converter 310 in order to reach a desired output level within a given time period. ) is applied to reach the output within the desired time. Here, the switch is controlled by the converter control signal (S _DC ).

The linear DC voltage regulator 315 according to an embodiment of the present invention may include a plurality of voltage sources and a cascade current amplifier.

At least some of the plurality of voltage sources (not shown) have potentials of different levels, for example, the first voltage source is DC 12V, the second voltage source is DC 24V, and the third to fifth voltage sources are DC 50V. In the cascade current amplifier (not shown), for example, a low power amplifier and amplifiers of the first to fourth driver amplifiers are combined in multiple stages.

Accordingly, the output level of the high frequency power amplifier 320 can be controlled to reach a set value within a predetermined time in the pulsing operation mode of the RF generator. Here, the pulsing operation mode of the RF generator means a mode in which the RF generator outputs high frequencies in pulse form instead of continuously. In this way, by coupling the linear DC voltage regulator 315 to the DC/DC converter 310, the DC input voltage with improved transient characteristics can be supplied to the high frequency power amplifier 320 when the RF generator operates in the pulsing operation mode.

As the DC input voltage in the form of a pulse is supplied to the high frequency power amplifier 320, the burden of deterioration of the switching element for the operation in the pulsing operation mode can be reduced. Here, when the high frequency power amplifier 320 is supplied with a DC input voltage in the form of a constant voltage and intends to output it as a pulsed RF output voltage, the switching element of the high frequency power amplifier 320 operates in a pulsing operation mode to exceed a desired output level. Since energy must be consumed as heat, the burden of deterioration inevitably increases.

The resonance filter 325 includes an inductor and a capacitor coupled in series and parallel, and outputs a sinusoidal resonance signal vR having a predetermined resonance frequency from a high frequency power signal output from the high frequency power amplifier 320.

The input sensor 330 is disposed between the resonance filter 325 and the variable matching network 335, detects an electrical signal output from the high frequency power supply side to the RF load, and outputs an electrical detection signal. Here, the electrical detection signal may be at least one of a forward detection current value (Ii), a forward detection voltage value (Vi), and forward power (P _F ) supplied to the RF load 360 from the high frequency power supply side.

The variable matching network 335 includes a variable inductor and/or a variable capacitor that are switched under the control of the variable network control signal Snet, and performs a function of reducing reflected power reflected from the RF load 360 .

The output sensor 340 is disposed between the variable matching network 335 and the RF load 360, detects an electrical signal reflected from the RF load toward the high frequency power supply side, and outputs an electrical detection signal. Here, the electrical detection signal may be at least one of a reverse detection current value (Io), a reverse detection voltage value (Vo), and reverse power (P _R ) reflected from the RF load 360 to the high frequency power supply side.

The controller 345 uses the control signal Scon applied from the outside and the electrical detection signals output from the input sensor 330 and the output sensor 340 to generate a power factor control signal Srec, a converter control signal S _DC , It outputs a regulator control signal (Sg), an amplification control signal (Spa) and a variable network control signal (Snet). In addition, the controller 345 calculates the load impedance using the forward power (P _F ) and the reverse power (P _R ), and uses the calculated load impedance to store an impedance frequency table as shown in Table 1 stored in the storage unit 350 . The switching frequency fs can be selected from

4 is an overall block diagram of a plasma power device in which an automatic frequency adjusting device according to another embodiment of the present invention is implemented.

A plasma power device according to an embodiment of the present invention includes an EMI filter 410, a rectifying unit 415, a smoothing unit 417, a high-frequency power amplifier 420 and 425, a transformer for coupling 430 and 435, Resonant filters 440 and 445, a combiner 450, an RF sensor 455, an RF load 460, a controller 465, and a storage unit 470 are included.

The EMI filter 410 serves to shield noise of electromagnetic waves included in the input three-phase commercial power supply.

The rectifying unit 415 rectifies the 3-phase voltage from the EMI filter 410 into a rectified voltage and outputs the rectified voltage.

The smoothing unit 417 smooths the smoothing voltage output from the rectifying unit 415 .

The high frequency power amplifiers 420 and 425 amplify the smoothing voltage of a predetermined level output from the smoothing unit 417 to generate a pulse wave high frequency power signal. The high frequency power amplification units 420 and 425 operate two or more power amplification modules in parallel to generate voltages and frequencies according to various load conditions. The first high frequency power amplification module 420 and the second high frequency power amplification module 425 are controlled by the first amplification control signal Pcon1 and the second amplification control signal Pcon2 output from the controller 470, respectively. 1 high frequency power signal v1 and a second high frequency power signal v2 are output. Here, the first amplification control signal Pcon1 means the first to fourth switching control signals S1, S2, S3, and S4 applied to the first to fourth switching elements, and the second amplification control signal Pcon2 denotes the fifth to eighth switching control signals S5, S6, S7, and S8 applied to the fifth to eighth switching elements.

The coupling transformers 430 and 435 induce the high-frequency power signal of the pulse waveform output from the high-frequency power amplifiers 420 and 425 to the secondary side, and electrically insulate the primary side and the secondary side, so that the user can be affected by the RF load. An electric shock accident can be prevented when contacting the included plasma chamber.

The resonance filters 440 and 445 include an inductor and a capacitor coupled in series and parallel, and a sinusoidal resonance signal having a predetermined resonance frequency from a high frequency power signal induced on the secondary side of the coupling transformer 430 and 435. outputs Here, the first resonance filter 440 outputs the first resonance signal vR1, and the second resonance filter 445 outputs the second resonance signal vR2.

The combiner 450 may be configured as a 3dB coupler. The first resonant signal vR1 is input to the first terminal T1 and the second resonant signal vR2 is input to the second terminal T2, respectively, and the load side terminal T3 and the terminating terminal T4 are coupled to the output side. And, the terminating impedance (Z) may be coupled to the terminating terminal (T4). The combiner 450 combines the first resonance signal vR1 and the second resonance signal vR2 and outputs a combined high frequency power signal. When the phase of the first resonance signal vR1 is ahead of the phase of the second resonance signal vR2 by 90 degrees, most of the combined high frequency power signal can be output to the load-side terminal T3. When the phase of the first resonance signal vR1 lags behind the phase of the second resonance signal vR2 by 90 degrees, most of the combined high frequency power signal can be output to the terminating terminal T4. Also, when the phase of the first resonance signal vR1 and the phase of the second resonance signal vR2 are the same, the combined high frequency power signal may be output to the load side terminal T3 and the termination terminal T4 in half. Meanwhile, the terminating impedance Z may be a resistor having a predetermined resistance value, and heat generated in the terminating resistor by the high frequency power signal applied through the terminating terminal T4 is dissipated using a fan (not shown). can

The RF sensor 455 is disposed between the combiner 450 and the RF load 460 and detects an electrical signal and outputs an electrical detection signal. Here, the electrical detection signal is the detection current value (Is), the detection voltage value (Vs), the forward power (P _F ) supplied from the combiner 450 to the RF load 460, and the computer from the RF load 460. It may be at least one or more of the reverse power (P _R ) reflected to the biner 450 .

The controller 465 uses the forward power command value PF_CMD applied from the outside and the electrical detection signal output from the RF sensor 455 to generate a voltage control signal Vcon, a first amplification control signal Pcon1, and second amplification. A control signal Pcon2 is generated. In addition, the controller 445 calculates the load impedance using the forward power (P _F ) and the reverse power (P _R ), and uses the calculated load impedance to store an impedance frequency table as in Table 1 stored in the storage unit 450 . The switching frequency fs can be selected from

The embodiments described in this specification and the accompanying drawings merely illustrate some of the technical ideas included in the present invention by way of example. Therefore, since the embodiments disclosed in this specification are not intended to limit the technical idea of the present invention but to explain it, it is obvious that the scope of the technical idea of the present invention is not limited by these embodiments. All modified examples and specific examples that can be easily inferred by those skilled in the art within the scope of the technical idea included in the specification and drawings of the present invention should be construed as being included in the scope of the present invention.

110: DC/DC converter
120: high frequency power amplifier
130: RF sensor
140: impedance matcher
150: controller
160: Plasma load
170: storage unit
210: impedance calculation unit
220: impedance frequency table
230: automatic frequency adjusting unit
240: switching frequency variation limiter
250: adder
260: switching frequency limiter
270: decision unit

Claims (10)

an impedance calculation unit that calculates and outputs an impedance of a complex number from forward power and reverse power presented as complex numbers;
an impedance frequency table for matching and storing an optimal switching frequency for each impedance and outputting a mapping switching frequency corresponding to the impedance of the complex number output from the impedance calculation unit;
an automatic frequency adjusting unit outputting a switching frequency variation from forward power and reverse power;
a switching frequency adder for outputting a switching frequency by adding the mapping switching frequency and the switching frequency variation; and
Determining unit for determining the switching frequency as an optimum switching frequency and storing it in the impedance frequency table when the reverse power is less than a predetermined power level when operating at the switching frequency.
An automatic frequency adjustment device comprising a.
The method of claim 1,
a switching frequency variation limiter for limiting upper and lower limit values for the switching frequency variation; and
Switching frequency limiter for limiting upper and lower limits for the switching frequency
Automatic frequency adjustment device further comprising a.
a high-frequency power amplifying unit that is controlled by an amplification control signal to amplify a DC voltage of a predetermined level to generate a pulse-wave high-frequency signal;
an impedance matcher controlled by a matching frequency control signal to match an impedance between the high frequency power amplifier and a load to a predetermined matching frequency;
an RF sensor configured to detect forward and reverse electrical signals between the high frequency power amplifier and the impedance matcher and output an electrical detection signal; and
A controller for generating the amplification control signal and the matching frequency control signal using a control signal applied from the outside and an electrical detection signal output from the RF sensor,
The controller is a plasma power device, characterized in that it comprises the automatic frequency adjusting device of claim 1.
a high frequency power supply including a high frequency power amplifying unit configured to amplify the smoothed voltage by first and second high frequency power amplifying modules connected in parallel to generate first and second high frequency power signals of pulse waveforms;
an RF sensor disposed between the high-frequency power source and the RF load and outputting an electrical detection signal by detecting an electrical signal; and
A controller outputting the high frequency power supply control signal using a control signal applied from the outside and an electrical detection signal output from the RF sensor,
The controller is a plasma power device, characterized in that it comprises the automatic frequency adjusting device of claim 1.
a DC/DC converter that converts a rectified voltage into a stable DC voltage according to a converter control signal;
a linear DC voltage regulator that amplifies voltage and current of a predetermined level using the DC voltage output from the DC/DC converter controlled by the regulator control signal to generate a pulse-type variable DC voltage required for pulse mode operation;
first and second high frequency power amplifiers generating pulsed high frequency power signals by amplifying the variable direct current voltage output from the linear direct current voltage regulator; and
A controller outputting the converter control signal and the regulator control signal;
The controller is a plasma power device, characterized in that it comprises the automatic frequency adjusting device of claim 1.
an impedance calculation step of calculating an impedance of a complex number from forward power and reverse power presented as complex numbers;
matching and storing an optimal switching frequency for each impedance, and outputting a mapping switching frequency corresponding to the impedance of a complex number output from the impedance calculation unit;
outputting a switching frequency variation from forward power and reverse power;
adding the mapping switching frequency and the switching frequency variation; and
Determining the switching frequency as an optimal switching frequency and storing it in the impedance frequency table when reverse power is less than a predetermined power level when operating at the switching frequency
Automatic frequency adjustment method comprising a.
The method of claim 6,
limiting upper and lower limit values for the switching frequency variation; and
limiting upper and lower limits for the current switching frequency;
Automatic frequency tuning method further comprising.
The method of claim 7,
The impedance calculation step is an automatic frequency adjustment method, characterized in that for calculating the reflection coefficient of the complex number using the following equation.

here,

is the reflection coefficient, Z _L is the load impedance, and Z ₀ is the characteristic impedance.
The method of claim 8,
The impedance calculation step is an automatic frequency adjustment method, characterized in that for calculating the impedance of the complex number using the following equation.

The method of claim 9,
The step of outputting the switching frequency variation is an automatic frequency adjustment method, characterized in that for outputting the switching frequency variation using the following equation.

Here, fs,offset is the switching frequency offset value,

is the reflection coefficient gain,

is the automatic frequency adjuster gain, and dP _R is the difference between the current reverse power and the previous reverse power.

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