KR100935406B1 - Plasma abnormal detecting apparatus and method for monitoring of plasma abnormal - Google Patents

Abstract

A transmission line connected to the load and transmitting an electrical signal of current or voltage, a sensing unit measuring an electrical signal of current or voltage of the transmission line, and a processing unit processing the electrical signal to generate at least one arc detection signal, The arc detection signal includes an arc detection device, characterized in that it is generated corresponding to the arc occurring in the load.

Plasma, arc, real-time monitoring

Description

Plasma anomaly detection device and plasma anomaly detection method {PLASMA ABNORMAL DETECTING APPARATUS AND METHOD FOR MONITORING OF PLASMA ABNORMAL}

1 is a block diagram showing a schematic configuration of an arc detection apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of the processing unit and the post processing unit described with reference to FIG. 1.

3 is a block diagram showing a configuration of a processing unit according to an embodiment of the present invention.

4 is a flowchart illustrating an arc detection method according to embodiments of the present invention.

5 is a waveform diagram illustrating an arc detection apparatus according to an embodiment of the present invention.

6 is a block diagram illustrating a configuration of a reference signal converter according to an embodiment of the present invention.

7 is a waveform diagram illustrating an arc detection apparatus according to an embodiment of the present invention.

8 is a block diagram showing a configuration of a processing unit according to an embodiment of the present invention.

9 is a waveform diagram illustrating an arc detection apparatus according to an embodiment of the present invention.

10 is a block diagram showing a configuration of a processing unit according to an embodiment of the present invention.

11 is a waveform diagram illustrating an arc detection apparatus according to an embodiment of the present invention.

12 is a block diagram showing a configuration of a processing unit according to an embodiment of the present invention.

13 is a waveform diagram illustrating an arc detection apparatus according to an embodiment of the present invention.

The present invention relates to a discharge device for generating a plasma, and more particularly, to an arc detection device and an arc detection method of a plasma generating device for discharging by using a radio frequency (RF) power source.

Plasma processing apparatuses are widely used in semiconductor manufacturing processes, material surface treatment, air pollution treatment, fusion fusion and the like. In particular, a plasma processing apparatus used in a semiconductor manufacturing process mainly uses an RF power source to generate a plasma.

On the other hand, in the plasma processing process using the RF power source, if there are structural defects or small particles in the discharge vessel, an arc may be generated to reduce the stability of the plasma processing process. In particular, in the case of a plasma processing apparatus for the manufacture of a semiconductor device, the arc can generate other small particles that cause a failure of the semiconductor device.

Accordingly, in order to monitor the stability of the plasma treatment process, a technique for monitoring whether an arc occurs in the chamber is required. According to the prior art, the generation of the arc has been monitored through analysis of the optical properties of the plasma. However, these optical monitoring methods have technical limitations that make it difficult to determine the type of arc. More specifically, arcs occurring in the chamber can be divided into fine arcs that are allowed up to a certain level and large arcs that require immediate response, but the optical monitoring method is difficult to provide information on the type of such arcs. In addition, the windows on the side wall of the chamber should be formed for observation of plasma emission for this optical monitoring, but as the processing time increases due to the contamination of the window, which reduces the reliability of the optical signal, It also increases.

Although a method of arranging a sensing device for monitoring arc generation inside the chamber can be considered, this method not only requires modification of the chamber structure but can also degrade the quality of the generated plasma.

One technical problem of the present invention is to provide an arc detection apparatus that enables to monitor in real time the presence of an arc generation and the abnormality of the plasma treatment process.

One technical problem of the present invention is to provide an arc detecting apparatus capable of monitoring the occurrence of an arc and an abnormality of a plasma treatment process without changing the chamber structure.

One technical problem of the present invention is to provide an arc detection method for monitoring in real time the presence of an arc generation and the abnormality of the plasma treatment process.

One technical problem of the present invention is to provide an arc sensing method for monitoring an arc generation and a plasma processing process without changing the chamber structure.

In order to achieve the above technical problem, the arc detection apparatus according to the present invention is connected to a load, a transmission line for transmitting an electrical signal of the current or voltage, a sensing unit for measuring the electrical signal of the current or voltage of the transmission line, and the electrical And a processor configured to process the signal to generate at least one arc detection signal, wherein the arc detection signal is generated corresponding to an arc generated in the load.

The arc detection method according to the present invention comprises the steps of measuring the electrical signal of the current or voltage transmitted along the transmission line connected to the load, by processing the electrical signal, at least one arc detection signal corresponding to the arc generation in the load Generating and analyzing the arc detection signal to determine arc generation at the load.

The above objects, other objects, features and advantages of the present invention will be readily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments described are provided so that the disclosure may be thorough and complete, and the spirit of the present invention will be fully conveyed to those skilled in the art.

An arc can be divided into a large arc and a fine arc. The electrical characteristics of the overall plasma of the RF discharge may vary greatly when the large arc is generated. This is because high density ionization can occur between the electrode in the discharge vessel and the ground. Therefore, when the large arc occurs, the RF discharge may become unstable as a whole or the RF discharge may not be maintained. When the incident power to the load is constant, when the large arc occurs, the current of the transmission line may increase rapidly, and the voltage of the transmission line may decrease. Alternatively, when the large arc occurs, the current of the transmission line increases, and the voltage of the transmission line may not change.

The duration of the large arc inside the plasma may be several nsec, but the duration of the current or voltage of the transmission line may be delayed by several tens of usec. The electrical signal of the transmission line according to the generation of the large arc is perturbated from the steady state electrical signal. The disturbance component due to the large arc may be in the 100 KHz region in the frequency space. When the large arc is generated, the input impedance of the load direction in the RF power stage may change instantaneously. However, if the duration of the large arc is very short and is restored to its original state, the matching network may not change with the occurrence of the large arc. However, if the RF discharge is not maintained due to the generation of a large arc, the matching network may change. Therefore, in the case of the large arc generation, if the RF discharge is maintained, the input impedance of the power stage may be due to the change in the load.

When the micro arc occurs, both the current and the voltage of the transmission line can be reduced, and the RF discharge can be maintained well. The fine arc may appear as an early phenomenon of the large arc. When the fine arc is generated, the duration of the current and voltage of the transmission line may be about several usec. The electrical signal of the transmission line according to the generation of the fine arc may be perturbated from the electrical signal in the steady state. The disturbance component due to the micro arc may be in the 1 MHz region in the frequency space. However, when the minute arc occurs, the input impedance of the power supply terminal may change instantaneously, but after several usec, the input impedance may be restored to the original state, so that the matching network may not change. Therefore, the input impedance in the load direction at the power supply stage when the fine arc is generated may be due to the change of the load.

The characteristic change time of the plasma may be in the range of several hundred msec at the transmission line. Therefore, the matching network may change for maximum power transfer in accordance with the characteristic change of the plasma. Therefore, when the plasma characteristic is changed, the input impedance in the load direction of the power supply terminal may be due to the change of the load and the matching network.

In reality, there is a limit to clearly distinguishing an arc into a large arc and a fine arc. This is because the arc can be caused by other causes besides the above-mentioned causes. Therefore, in the present invention, it is divided into a first type arc and a second type arc. That is, the case where the current of the transmission line becomes smaller than the normal state is called a first type arc. The first type arc may include the fine arc. The case where the current of the transmission line becomes larger than the normal state is called a second type arc. The second type arc may include the large arc described above.

When an arc occurs, the electrical characteristics of the transmission line change drastically. Therefore, the investigation of the electrical characteristics of the transmission line may be the most reliable means for determining whether the arc occurs. In addition, the electrical characteristics of the transmission line can be monitored in real time.

Electrical characteristics of the transmission line may be affected by arc generation and plasma characteristic change. Therefore, it is necessary to distinguish between the plasma characteristic change and the arc. The duration of the plasma characteristic change is about several hundred msec in time, and the duration of the arc may last for several usec to several hundred usec. Therefore, in order to distinguish the plasma characteristic change from the arc, it is preferable to determine whether the arc is generated by measuring the current and voltage of the transmission line and the duration of these changes.

On the other hand, it is possible to determine whether the arc is generated using the input impedance, reflection coefficient, power consumption, etc. of the transmission line, the method is difficult to determine the type of the arc, it is difficult to distinguish between the plasma characteristics change and the arc.

Hereinafter, with reference to the accompanying drawings will be described in detail preferred embodiments of the present invention.

1 is a block diagram showing a schematic configuration of an arc detection apparatus according to an embodiment of the present invention.

Referring to FIG. 1, an arc sensing apparatus according to the present invention is disposed between a load 24, an RF power source 10 supplying power to the load 24, and the load 24 and the RF power source 10. Which may include a transmission line 36 and a matching network 38. A sensing unit 22 is disposed around the transmission line 36 to measure an electrical signal of a current or voltage of the transmission line 36, and the sensing unit 22 is provided to a processing unit 25 that processes the electrical signal. Electrically connected. In addition, the arc detecting apparatus further includes a post processor 32 that determines whether an arc is generated and the type of the arc. The arc sensing device may be controlled by the controller 34.

The RF power supply 10 supplies incident power to the input terminals N1 and N2. Part of the incident power supplied through the transmission line 36 is consumed by the load 24, and the other part is reflected from the load 24 to the input terminals N1 and N2. Accordingly, the matching network 38 is configured such that the maximum value of the incident power can be delivered to the load 24, and may be disposed between the input terminals N1 and N2 and the load terminals N3 and N4. . The driving frequency of the RF power supply 10 may be one of 200 KHz to 500 MHz. According to an embodiment of the present invention, the driving frequency may be 13.56 MHz.

According to a modified embodiment of the present invention, the RF power source 10 may be composed of one or more power sources. For example, when the RF power supply 10 is configured as a first power supply and a second power supply, driving frequencies of the first power supply and the second power supply may be different from each other. In addition, the first power source and the second power source may be connected to the same load. In this case, a first matching network and a first sensing unit may be disposed between the first power source and the load, and a second matching network and a second sensing unit may be disposed between the second power source and the load. Alternatively, after the first matching network and the second matching network are combined together, one sensor may be disposed in front of the load.

The internal impedance of the RF power supply 10 may be 50 ohms, and the characteristic impedance of the transmission line 36 may be 50 ohms. The transmission line 36 may include at least one of a coaxial cable, two wires, a strip line, and a bus bar.

The load 24 is connected to the load terminals N3 and N4 and may be an electrode or an antenna for generating plasma. The impedance of the load 24 may change with time due to a change in plasma characteristics or arc generation. In this case, the reactances of the variable reactance elements 12 and 14 of the matching network 38 may be changed to maximize the aforementioned incident power. The detector 22 is arranged to measure an electrical signal of a transmission line 36 connecting the input terminals N1 and N2 and the load terminals N3 and N4. The detector 22 may be disposed between the load terminals N3 and N4 and the matching network 38, or between the input terminals N1 and N2 and the matching network 38. In addition, the detector 22 may be located inside the matching network 38.

The detector 22 includes at least one sensor disposed around the transmission line 36, wherein the sensor measures a current flowing through the transmission line and outputs a current signal SI, and a voltage of the transmission line. It may include at least one of the voltage meter for measuring and outputting the voltage signal (SV). The current meter may include a coil for measuring induced electromotive force. For example, the current meter may be a Rogowski coil measuring an electromotive force. The voltage meter may be a voltage divider using an electrode or a resistor.

The processing unit 25 includes at least one of a current processing unit and a voltage processing unit, wherein the current processing unit is connected to the current measuring unit, and the arc detection signal from the electrical signal SI (see OUT1 and OUT2 of FIG. 2). The voltage processor may be connected to the voltage meter and configured to generate the arc detection signal OUT3 from the electrical signal SV. The arc detection signals OUT1, OUT2, and OUT3 may have a width corresponding to the arc duration generated by the load 24.

The post processor 32 may be configured to receive the arc detection signals OUT1, OUT2, and OUT3, and determine whether an arc is generated and the arc type. More specifically, according to the present invention, whether the arc is generated can be determined by analyzing the pulse width of the arc detection signals OUT1, OUT2, OUT3, the arc type is the analysis of the sign of the arc detection signals It can be determined through. To this end, the post-processing unit 32 analyzes the width of the arc detection signal to determine whether an arc is generated, the arc generation determiner 46 and the arc type determination to determine the type of arc by analyzing the sign of the arc detection signal. And at least one of the groups 48.

The control unit 34 controls the arc detection device and communicates with the processing unit 25 and the post processing unit 32. The controller 34 may display the result of the processor 23 on an external display device. The communication may use RS232, RS485, or Devicenet / CAN. The controller may be a computer.

FIG. 2 is a block diagram illustrating a schematic configuration of the processor 25 and the post processor 32 described with reference to FIG. 1.

According to the present invention, the processing unit 25 may include at least one of the first and second current processing units and the voltage processing unit. In this case, the first and second current processors are connected to the current meter to generate the arc detection signals OUT1 and OUT2 from the current signal SI, and the voltage processor is connected to the voltage meter. And generate the arc detection signal OUT3 from the voltage signal SV. In this case, except for a difference in the type of the input signal (ie, current and voltage) and a difference in the method in which the respective signals are processed, the first and second current processing units and the voltage processing unit have a substantially similar structure. . Therefore, in order to avoid the complexity of the description, the basic structure of the processing unit 25 configured to generate one arc detection signal will be described below.

1 and 2, the processor 25 may include at least one reference signal generator 44 generating the reference signal REF and at least one comparison signal generator generating the comparison signal IN. 40 and at least one comparator 42 generating the arc detection signal OUT by comparing the reference signal REF with the comparison signal IN. The reference signal REF and the comparison signal IN may be generated using the electrical signal.

More specifically, the comparison signal generator 40 receives the current signal SI or the voltage signal SV of the detector 22 and outputs the comparison signal IN including the disturbance component due to the arc. That is, the comparison signal IN includes a disturbing frequency component due to the arc. In this case, the comparison signal IN does not include a driving frequency component of the RF power source 10, but may include a frequency component due to a DC component or a change in plasma characteristics. The disturbance component due to the arc means a frequency component that appears in the current signal SI or the voltage signal SV due to arc generation in the load 24.

The reference signal generator 44 may be configured to output the reference signal REF from the current signal SI or the voltage signal SV of the detector 22. In this case, the disturbance component due to the arc included in the comparison signal IN is not included in the reference signal REF. According to an exemplary embodiment of the present invention, the reference signal generator 44 processes one of the current signal SI and the voltage signal SV by using the offset signal from the controller 34, thereby performing the reference. It may be configured to output a signal REF. Like the comparison signal IN, the reference signal REF does not include a driving frequency component of the RF power source 10 but may include a frequency component due to a DC component or a change in plasma characteristics.

The comparison signal generator 40 may include at least one of a comparison signal rectifier for rectifying the electrical signal, a comparison signal filter for extracting a disturbance component due to an arc from the electrical signal, and a comparison signal converter for changing the amplitude or polarity of the electrical signal. It may include one.

Similarly, the reference signal generator 44 may include a reference signal rectifier for rectifying the electrical signal, a reference signal filter for removing disturbance components due to arc from the electrical signal, and a reference for changing the amplitude or polarity of the electrical signal. It may include at least one of the signal converter. The reference signal generator 44 may further include at least one of a combiner and an offset signal generator for generating an offset signal. In this case, the combiner may be an adder or a subtractor. That is, the combiner may add or subtract two input signals and output the result. According to another embodiment of the present invention, the combiner may use an OP AMP.

 The reference signal and comparison signal rectifiers rectify a predetermined input signal (for example, current signal SI or voltage signal SV) and output reference and comparison rectified signals, respectively. According to an embodiment of the present invention, these rectifiers may be one of a rectifier using a diode, a rectifier using a multiplier and a low pass filter, and a rectifier using an op amp and a filter. According to the multiplier and the rectifier using the low pass filter, the multiplier squares the input signal, and the low pass filter may extract low frequency components from the signal output from the multiplier. According to another embodiment of the present invention, the reference and comparison signal rectifiers are functional in terms of a half wave rectifier, a full wave rectifier, an RMS detector, or a peak detector. It may be any one of, and may include a filter.

The reference signal filter is configured to remove a component of the disturbing frequency band caused by the arc from the input signal. The reference signal filter may be an active filter or a passive filter. In addition, in functional terms, the reference signal filter may be a low pass filter or a band pass filter.

The reference signal converter may be configured to output by changing the magnitude of the input signal or by changing the polarity of the input signal. The reference signal converter may be at least one of a log amplifier, an attenuator, and a negative gain amplifier.

The comparison signal filter may be configured to extract a component of a disturbing frequency band by an arc from an input signal. As a result, the frequency band filtered by the comparison signal filter is different from the frequency band filtered by the reference signal filter. The comparison signal filter may be an active filter or a passive filter. In addition, in functional terms, the comparison signal filter may be a low pass filter or a band pass filter.

The comparison signal converter may be configured to output by changing the magnitude of the input signal or by changing the polarity of the input signal. The comparison signal converter may include at least one of a log amplifier, an attenuator, and a negative gain amplifier. According to the present invention, the magnitude of change in the signal changed by the comparison signal converter may be different from the magnitude of change in the signal changed by the reference signal converter.

According to one embodiment of the invention, the reference signal generator 44 is a reference signal rectifier for rectifying the electrical signal, a reference signal filter for removing the disturbance component by the arc of the electrical signal, and the amplitude of the electrical signal Or at least one of a reference signal converter for changing polarity. However, the reference signal filter is configured to remove the disturbance component due to the arc of the electrical signal rectified in the reference signal rectifier, and the reference signal converter changes the amplitude or polarity of the electrical signal filtered by the reference signal filter. It is configured to.

According to an embodiment of the present invention, the comparison signal generator is a comparison signal rectifier for rectifying the electrical signal, a comparison signal filter including a disturbance component by an arc in the electrical signal and the comparison to change the amplitude and polarity of the electrical signal At least one of the signal converters. However, the comparison signal filter is configured to extract a disturbance component due to the arc of the electrical signal rectified by the comparison signal rectifier, and the comparison signal converter may change the amplitude or polarity of the electrical signal filtered by the comparison signal filter. have.

The comparison unit 42 compares the comparison signal IN with the reference signal REF and outputs an arc detection signal OUT. According to the difference between the reference signal and the comparison signal, the arc detection signal OUT may be output as high or low, and the duration of the arc detection signal OUT is determined by the arc generated at the load. It can be proportional to the duration.

According to an embodiment of the present invention, the comparator 42 may be any one of a comparator, an op amp without negative feedback, and a differential amplifier. The comparator turns the output high when the voltage at the "+" terminal is greater than the voltage at the "-" terminal and turns the output low when the voltage at the "-" terminal is greater than the voltage at the "+" terminal. LOW). The comparison signal IN may be input to the "+" terminal of the comparator, and the reference signal REF may be input to the "-" terminal. The above operation of the comparison unit 42 is merely illustrative of a method for implementing the technical idea of the present invention, and may be variously modified as necessary.

According to the present invention, the post processing unit 32 receives the arc detection signals OUT1, OUT2, and OUT3 as described above with reference to FIG. 1, and the arc detection signals OUT1, OUT2, and OUT3. An arc generation determiner 46 for determining whether the arc is generated by measuring the pulse width of the arc and the arc type determiner 48 for determining the arc type by comparing the sign of the arc detection signals.

The arc detection signal may include noise components irrelevant to the arc and components corresponding to changes in plasma characteristics. Therefore, in order to determine whether an arc has occurred, it is necessary to remove these components. The pulse width due to the noise component is mostly shorter than the minimum value of the pulse width due to the arc, and the pulse width due to the plasma characteristic change is longer than the maximum value of the pulse width due to the arc. The arc generation determiner 46 according to the present invention is configured to use this characteristic to determine whether the arc has occurred without a misjudgment caused by the component according to the change in the noise component and the plasma characteristic.

According to an embodiment of the present invention, the arc generation determiner 46 may include a programmable logic device (PLD) to measure the pulse width of the arc detection signal. For example, the PLD may be operated when the arc detection signals OUT1, OUT2, and OUT3 rise above the predetermined first reference level, and stop the operation when the arc detection signals OUT1, OUT2, OUT3 rise below the second reference level. In this case, the width of the signals is determined by the operating time of the pulse width meter. The arc generation determiner 46 has a circuit configured to determine whether a pulse width of the arc detection signal is between a first reference width and a second reference width in order to minimize the misjudgment as to whether or not the above-described arc has occurred. can do.

More specifically, the first reference width may be a number usec. The second reference width may be several hundred usec. As described above, the arc detection signal that is less than the first reference width is likely to be a result of noise, and the arc detection signal that exceeds the second reference width may be a result of a characteristic change of the plasma. In these cases, therefore, the arc generation determiner 46 does not generate an arc generation signal. The first reference width and the second reference width may be set from the controller 34 and may be variously selected as necessary.

The arc type determiner 48 compares the first arc detection signal OUT1, the second arc detection signal OUT2, and the third arc detection signal OUT3 to distinguish between the first type arc and the second type arc. Can be. When the first type arc occurs, both the current and the voltage of the transmission line may decrease, and when the second type arc occurs, the current of the transmission line increases and the voltage decreases. However, when the second type arc occurs, the current of the malleable wire may increase, but the voltage may hardly change.

The arc type determiner 48 according to the invention is configured to use this feature to determine whether the arc is a first type arc or a second type arc.

More specifically, when the sign of the first arc detection signal OUT1 or the second arc detection signal OUT2 and the sign of the third arc detection signal OUT3 are the same, the arc type determiner 48 The generated arc can be determined as a first type arc. In addition, when the sign of the first arc detection signal OUT1 or the second arc detection signal OUT2 and the sign of the third arc detection signal OUT3 are different from each other, the arc type determiner 48 generates the generated arc. The arc can be determined as a second type arc. The direction of the signal of the first arc detection signal OUT1, the second arc detection signal OUT2, or the third arc detection signal OUT3 is changed depending on the input terminals of the "+" and "-" portions of the comparator. Can be.

According to a modified embodiment of the present invention, when the sign of the current arc detection signal is a negative value, it can be determined as a first type arc, and if it is a positive value, it can be determined as a second type arc. That is, if the first arc detection signal OUT1 is a negative sign, it may be determined as a first type arc, and if the second arc detection signal OUT2 is a positive signal, it may be determined as a second type arc. The direction of the signal of the first arc detection signal OUT1, the second arc detection signal OUT2, or the third arc detection signal OUT3 is changed depending on the input terminals of the "+" and "-" portions of the comparator. Can be.

According to one embodiment of the present invention, the arc type determiner 48 may further include a first type arc counter that calculates the number of first type arcs. The arc type determiner 48 may output the first type arc count signal DISP1 according to the number of first type arcs calculated using the first type arc counter. More specifically, when the arc of the first type occurs more than a predetermined number of times per unit time, the arc type determiner 48 may output a warning signal. When it is determined that the generated arc is the second type arc, the arc type determiner 48 may output the second type arc signal DISP2. The reference number for generating the warning signal associated with the first type arc may be controlled by the controller 34.

According to an embodiment of the present invention, the arc generation determiner 46 and the arc type determiner 48 may use a programmable logic device (PLD) for real time detection. That is, the arc generation determiner 46 and the arc type determiner 48 having the above-described technical features may be integrated in a programmable logic device.

The controller 34 may include an indicator for visually displaying at least one of information related to signals generated by the processor 25 and the post processor 32 to a user. For example, the indicator receives the second type arc signal DISP2 and the first type arc count signal DISP1, displays the number of first type arcs per unit time, and is equal to or greater than a predetermined reference number per unit time. In this case, the first type arc warning signal may be displayed, and the second type arc warning signal may be displayed.

As described above, the processing unit 25 may include at least one of the first and second current processing units and the voltage processing unit. In this case, each of the first and second current processors and the voltage processor includes the reference signal generator 44, the comparison signal generator 40, and the comparer 42 described above with reference to FIG. 2. It can be provided.

According to a modified embodiment of the present invention, the processor 25 may have only a voltage processor that processes the voltage signal SV without the current processors. According to another modified embodiment of the present invention, the processor 25 may have at least one of the first current processor and the second current processor for processing the current signal (SI) without the voltage processor.

3 is a block diagram illustrating a configuration of a first current processor according to an exemplary embodiment of the present invention.

 1, 2, and 3, the first current processor 26 includes a comparison signal generator 40, a reference signal generator 44, and a comparator 42. The comparison unit 42 compares the first comparison signal IN1a of the comparison signal generator 40 with the first reference signal REF1a of the reference signal generator 44 to determine the first arc detection signal OUT1. )

The comparison signal generator 40 may include at least one of a comparison signal rectifier 60 for rectifying an electrical signal and a comparison signal filter 62 for including a disturbing component by an arc in the electrical signal.

The reference signal generator 44 may include a reference signal rectifier 64 for rectifying an electrical signal, a reference signal filter 66 for removing a disturbance component due to an arc from the electrical signal, and changing an amplitude or polarity of the electrical signal. It may include at least one of the reference signal converter 68.

Referring to FIG. 3, the comparison signal rectifier 60 outputs a comparison rectification signal RCT1a from the current signal SI. The comparison signal filter 62 receives the comparison rectified signal RCT1a and outputs a first comparison signal IN1a including a disturbing frequency component due to an arc. According to one embodiment of the invention, the comparison signal filter 62 is configured to remove the drive frequency component of the RF power supply 10 from the comparison rectified signal RCT1a. That is, the driving frequency component is not included in the first comparison signal IN1a.

The reference signal rectifier 64 receives a current signal SI of the detector 22 and outputs a reference rectified signal RCT2a. The comparison signal rectifier 60 and the reference signal rectifier 66 may be the same. That is, according to an embodiment of the present invention, the comparison signal generator 40 and the reference signal generator 44 may share one rectifier 60 or 64.

The reference signal filter 66 receives the reference rectified signal RCT2a and outputs a preliminary reference signal RE1a from which the driving frequency component of the RF power supply 10 and the disturbing frequency component by the arc are removed.

When both the comparison signal filter 62 and the reference signal filter 66 are low frequency filters, the cutoff frequency of the comparison signal filter 62 may be greater than that of the reference signal filter. In the case where both the reference signal filter 66 and the comparison signal filter 62 are low pass filters, the cutoff frequency of the reference signal filter 66 is low enough so that the reference signal does not contain information about arc. (For example, approximately 10 KHz). The cutoff frequency of the comparison signal filter 62 may be set to a value (eg, approximately 250 KHz) in which the information of the arc may be included in the comparison signal.

Since the preliminary reference signal RE1a and the first comparison signal IN1a are similar in DC bias, their direct comparison is inadequate for obtaining meaningful results. Here, the DC bias means a difference between the reference levels when the signal distortion due to the arc or the like does not occur and the signal distortion due to the arc or the like occurs. The reference signal converter 68 is configured to generate a difference between the preliminary reference signal RE1a and the first comparison signal IN1a. For example, the reference signal converter 68 outputs a first reference signal REF1a of which the magnitude or polarity of the preliminary reference signal RE1a is changed.

The comparison unit 42 compares the first comparison signal IN1a of the comparison signal generator 40 with the first reference signal REF1a of the reference signal generator 44 to compare the first arc detection signal OUT1. ) The comparator 42 may be an OP AMP or a comparator without negative feedback.

4 is a flowchart illustrating an arc detection method according to embodiments of the present invention. The arc sensing method described below may be implemented through the arc sensing apparatus described above with reference to FIGS. 1 to 3. According to another embodiment of the present invention, the arc sensing method described below may include determining whether an arc is generated and an arc type from an electrical signal measured using predetermined software.

Referring to FIG. 4, the arc sensing method according to the present invention may include measuring an electrical signal of a current or voltage of a transmission line connected to a load (S10), and processing the electrical signal to at least correspond to arc generation at the load. Generating one arc detection signal (S20), analyzing the arc detection signal to determine whether an arc occurs in the load (32), and analyzing the arc detection signal to determine an arc type at the load. And determining 34.

In this case, the generating of the arc detection signal (S20) may include generating a reference signal from the electrical signal (S22), generating a comparison signal from the electrical signal (S24), and comparing the reference and comparison signals. Generating the arc detection signal (S26). The reference signal, the comparison signal and the arc detection signal may be generated through the method described with reference to FIGS. 1 to 3. Similarly, the determination of whether the arc is generated and the type of the arc may be made through the method described with reference to FIGS. 1 to 3.

5 is a waveform diagram illustrating an arc detection apparatus according to an embodiment of the present invention. Specifically, this embodiment relates to signals generated in the arc sensing device having the first current processor described in FIG. 3. FIG. 5 illustrates an embodiment in which half-wave rectifiers are used as the reference signal rectifier 64 and the comparison signal rectifier 60, and a low pass filter is used as the comparison signal filter 62 and the reference signal filter 66. This is a waveform diagram of the signals generated. According to this embodiment, the reference signal filter 66 is a low pass filter having a cutoff frequency smaller than that of the comparison signal filter 62.

FIG. 5A illustrates a waveform of the current signal SI output from the sensing unit 22, and FIG. 5B illustrates a comparison rectified signal output from the comparison signal rectifier 60. Referring to FIG. RCT1a and a waveform of the reference rectified signal RCT2a output from the reference signal rectifier 64 are shown, and FIG. 5C shows a first comparison signal IN1a output from the comparison signal filter 62, The waveforms of the preliminary reference signal RE1a output from the reference signal filter 66 and the first reference signal REF1a output from the reference signal generator 44 are shown, and FIG. The waveform of the first arc detection signal OUT1 output from the comparator 42 is shown, and FIG. 5E illustrates the output signal of the first arc counter output from the arc type determiner 48. DISP1) shows the waveform.

Referring to FIG. 5A, the detector 22 outputs a current signal SI obtained by measuring a current flowing through a transmission line. The current signal SI includes information according to a characteristic change of the plasma in addition to the information according to the arc. In this case, the content of the current signal is a change in the measured current, but the shape of the signal may be converted into a voltage and output. The current signal SI caused by the first type arcs A, B, C, and D rapidly decreases and returns to a normal level. On the other hand, when there is a change in the characteristics of the plasma, the amplitude of the current signal (SI) can be increased (or decreased) from V1 to V2, as shown in the time periods t3 and t4. However, the duration t4-t3 of the characteristic change of the plasma is much longer than the duration t2-t1 of the change of the current signal SI due to arc generation. The arc sensing device according to the present invention uses the difference in the duration of these characteristics to distinguish between the plasma characteristic change phenomenon and the arc phenomenon. The durations of the first type arcs A, B, C, and D may range from several usec to several hundred usec.

Referring to FIG. 5B, the comparison signal rectifier 60 and the reference signal rectifier 64 are half-wave rectified from the current signal SI to output the comparison rectified signal RCT1a and the reference rectified signal RCT2a, respectively. do. That is, the comparison rectified signal RCT1a includes only one of the positive and negative components of the current signal SI. In this case, the disturbance frequency component and the frequency component of the plasma characteristic change due to the first type arc are not removed by the comparison signal rectifier 60 and the reference signal rectifier 64, respectively, and the comparison rectified signal RCT1a and It is included in the reference rectified signal RCT2a.

Referring to FIG. 5C, the comparison signal filter 62 outputs the first comparison signal IN1a from which the driving frequency component of the RF power supply 10 is removed from the comparison rectified signal RCT1a. At this time, the first comparison signal IN1a still contains a disturbance component due to an arc. To this end, the comparison signal filter 62 may be a low pass filter. The cutoff frequency of the low pass filter 622 is 250 KHz which is smaller than the driving frequency (13.56 MHz) of the power supply. However, if the cutoff frequency of the comparison signal filter is too small, the information about the arc may be lost in the first comparison signal IN1a. The cutoff frequency of the low pass filter 62 is preferably a value smaller than the driving frequency of the power supply (for example, 13.56 MHz) (for example, 250 KHz). That is, the first comparison signal IN1a includes information on the plasma characteristic change and information on the first type arcs A, B, C, and D. In addition, when there is a second type arc, the first comparison signal IN1a may include information on the second type arc.

Referring to FIG. 5C, the reference signal filter 66 outputs a preliminary reference signal RE1a from which the disturbance frequency component and the RF driving frequency component by the arc are removed from the reference rectified signal RCT2a. The reference signal filter 66 is a low pass filter having a cutoff frequency capable of removing a disturbing frequency component due to the arc, and the cutoff frequency may be 10 KHz. Since the duration of the arc is between several usec and hundreds of usec, the cutoff frequency of the reference signal filter is preferably 10 kHz. On the other hand, the reference signal filter 66 is preferably configured so as not to extinguish the information on the characteristic change of the plasma, and as a result, the preliminary reference signal RE1a is changed to the plasma characteristic change as shown in the section t3-t4. DC bias increases between t3 and t4 since it contains information about the period (t3 to t4). That is, as shown, the preliminary reference signal RE1a exhibits a DC bias characteristic that increases in the period t3 to t4 as in the case of the current signal SI.

Referring to FIG. 5C, the preliminary reference signal RE1a and the first comparison signal IN1a have the same magnitude as the DC bias is indistinguishable from each other. The reference signal converter 68 has a magnitude that can be distinguished from the first comparison signal IN1a by changing (for example, reducing) the preliminary reference signal RE1a at a predetermined ratio by a predetermined ratio. The first reference signal REF1a is generated. The gain g = REF1a / RE1a of the reference signal converter 68 may be adjusted by the controller 34. The gain of the reference signal converter 68 may be a value between 0.1 and 0.8. Since the first reference signal REF1a includes plasma characteristic change information (t3 to t4 section), the DC bias increases between t3 and t4.

Referring to FIG. 5D, the comparison unit 42 receives the first comparison signal IN1a and the first reference signal REF1a, compares the signals, and corresponds to the disturbance caused by the arc. The first arc detection signal OUT1 is output. Since the first comparison signal IN1a and the first reference signal REF1a include information corresponding to the plasma characteristic change and are included in both, the comparator 42 does not treat the plasma characteristic change as an arc. The information on the plasma characteristic change is not included in the first arc detection signal OUT1. However, as described above, in the current signal SI, the first type arcs A, B, C, and D are disturbed by the arc, but the first reference signal IN1a is included in the disturbance component. Since it is not included in REF1a, pulses a, b, c, d corresponding to the arc generation are generated as shown in the first arc detection signal OUT1. Meanwhile, according to one embodiment of the present invention, when an arc occurs after the plasma characteristic is changed (D), the width of the pulse d corresponding to (D) in the first generated arc detection signal OUT1 is Widths of the pulses a, b, and c generated in the first arc detection signal OUT1 before the plasma characteristic is changed may be different.

Referring to FIGS. 2 and 5E, the post processor 32 receives the first arc detection signal OUT1 to measure a pulse width, and measures the pulses a, b, c, and d. It is determined whether or not this result is caused by the arc. According to an embodiment of the present invention, when it is determined that the pulse is an arc, the arc type determiner 48 outputs the first type arc counter signal DISP1 to accumulate the number of arc occurrences.

6 is a block diagram showing the configuration of a reference signal converter 68 according to an embodiment of the present invention.

3 and 6, the reference signal converter 68 includes an analog to digital converter (ADC) 70, a microcontroller 74, and a digital analog converter (DAC) 72. The analog digital converter (ADC) 70 converts the preliminary reference signal RE1a into a digital signal. The microcontroller 74 converts the magnitude of the digital signal. The digital analog converter (DAC) 72 outputs the analog-type first reference signal REF1a from the size-converted digital signal. The sampling time of the analog-to-digital converter 70 may be maintained below a few usec to follow the change of the preliminary reference signal RE1a. The controller 34 may control the microcontroller 74.

7 is a waveform diagram illustrating an arc detection method according to an embodiment of the present invention. Specifically, this embodiment relates to signals generated in the arc sensing device having the first current processing section 26 described in FIG. 7 uses half-wave rectifiers as the reference signal rectifier 64 and the comparison signal rectifier 60, the comparison signal filter 62 uses a bandpass filter, and a low pass to the reference signal filter 66. This is a waveform diagram of signals generated in an embodiment using a filter. According to this embodiment, the low frequency cutoff frequency of the comparison signal filter 62 is 10 to 100Hz, the high frequency cutoff frequency is 250 KHz, and the cutoff frequency of the reference signal filter 66 is 10KHz.

FIG. 7A illustrates a waveform of the current signal SI output from the sensing unit 22, and FIG. 7B illustrates a comparison rectified signal RCT1b output from the comparison signal rectifier 60. And a waveform of the reference rectified signal RCT2b output from the reference signal rectifier 64, and FIG. 7C illustrates a first comparison signal IN1b output from the comparison signal filter 62 and the reference. A waveform of the preliminary reference signal RE1b output from the signal filter 66 and the first reference signal REF1b output from the reference signal generator 44 is shown, and FIG. 7D illustrates the comparison unit (d). FIG. 7E shows a waveform of the first arc detection signal OUT1 output from 42, and FIG. 7E shows the waveform of the output signal DISP1 of the first arc counter output from the arc type determiner 48. FIG. Shows. For brevity of description, hereinafter, description of contents overlapping with the embodiments described with reference to FIGS. 3 to 5 will be minimized.

Referring to FIG. 7C, as described above with reference to FIG. 5C, the comparison signal filter 62 receives the comparison rectified signal RCT1b and the driving frequency of the RF power supply 10. The DC component is removed but the first comparison signal IN1b including the disturbance component due to the arc is output. However, the first comparison signal IN1b does not contain plasma characteristic change information (t3 to t4 section), but contains information about the first type arcs A, B, C, and D. In addition, when there is a second type arc, the first comparison signal IN1b may include information on generation of the second type arc.

As described above with reference to FIG. 5C, since the preliminary reference signal RE1b includes information on plasma characteristic change, the DC bias increases between t3 and t4. The reference signal converter 68 may generate at least one of an amplitude and a sign of the preliminary reference signal RE1b to generate a first reference signal REF1b. The reference signal converter 68 may be a sound gain amplifier, and the gain may be adjusted by the controller 34. The gain g = REF1b / RE1b of the sound gain amplifier may be a value between -1.0 and -0.1. Accordingly, since the first reference signal REF1b includes a section in which the plasma characteristics change, the DC bias decreases between t3 and t4.

3 and 7 (d), the comparator 42 compares the comparison signal IN1b with the first reference signal REF1b and outputs a first arc detection signal OUT1. As described above, since the disturbance component due to the arc is included in the first comparison signal IN1b but not included in the first reference signal REF1b, the first arc detection signal OUT1 is as shown. It has pulses (a, b, c, d) corresponding to the arc generation. Meanwhile, according to an embodiment of the present invention, the width of the pulse d corresponding to the arc generated after the plasma characteristic is changed is the widths of the pulses a, b, and c generated before the plasma characteristic is changed. Can be different from.

8 is a block diagram showing a configuration of a processing unit according to an embodiment of the present invention. For brevity of description, hereinafter, description of contents overlapping with the embodiments described with reference to FIGS. 3 to 5 will be minimized.

1, 2 and 8, the processor 25 according to this embodiment may be used for any one of the above-described first current processor, second current processor, and voltage processor. The first current processor 26c includes a comparison signal generator 40c, a reference signal generator 44c, and a comparator 42c. The comparison unit 42c compares the first comparison signal IN1c of the comparison signal generator 40c with the first reference signal REF1c of the reference signal generator 44c to compare the first arc detection signal OUT1. )

Since the embodiment of the present invention is similar to that described with reference to FIGS.

The comparison signal generator 40c includes a comparison signal rectifier 100 for rectifying an electrical signal, a comparison signal filter 102 for including a disturbing component by an arc in the electrical signal, and an amplitude or polarity of the electrical signal. It may include at least one of the comparison signal converter 104 to change at least one of the.

The reference signal generator 44c includes at least one of a reference signal rectifier 106 for rectifying an electrical signal, a reference signal filter 108 for removing a disturbance component due to an arc from the electrical signal, and an amplitude or polarity of the electrical signal. At least one of: a reference signal converter 110 for changing a signal; an offset signal generator 114 for generating an offset signal OSc; and a combiner 112 for combining the offset signal with an output signal of the reference signal converter 110. can do.

The comparison signal rectifier 100 receives the current signal SI and outputs a comparison rectification signal RCT1c. The comparison signal filter 102 receives the comparison rectified signal RCT1c and removes a driving frequency component of the RF power supply, and outputs a preliminary comparison signal SN1c including a disturbing component by an arc. The comparison signal converter 104 outputs a first comparison signal IN1c obtained by converting at least one of amplitude or polarity of the signal from the preliminary comparison signal SN1c. The comparison signal converter 104 may be a log amplifier. The log amplifier has an output proportional to the log value of the input signal.

 The reference signal rectifier 106 receives the current signal SI of the detector 22 and outputs a reference rectified signal RCT2c. The comparison signal rectifier 100 and the reference signal rectifier 106 may be the same. In addition, the comparison signal generator 40c and the reference signal generator 44c may share the comparison signal rectifier 100 and the reference signal rectifier 106. The reference signal filter 108 receives the reference rectified signal RCT2c and outputs a preliminary reference signal RE1c from which the driving frequency component of the RF power source and the disturbance component by the arc are removed. The reference signal filter 108 may be a low pass filter. The cutoff frequency of the comparison signal filter 102 may be greater than the cutoff frequency of the reference signal filter 108. The reference signal converter 110 outputs a conversion reference signal PR1c obtained by converting at least one of amplitude or polarity from the preliminary reference signal. The reference signal converter 110 may be a log amplifier. The log amplifier has an output proportional to the log value of the input.

The offset signal generator 114 may generate the offset signal OSc. The offset signal OSc of the offset signal generator 114 may be set by the controller 34.

The combiner 112 may output the first reference signal REF1c by combining the conversion reference signal PR1c and the offset signal OSc generated by the offset signal 114. The combiner 112 may use an OP AMP. The combiner 112 may be an adder or a subtractor.

The comparison unit 42c compares the first comparison signal IN1c with the first reference signal REF1c and outputs a first arc detection signal OUT1.

9 is a waveform diagram illustrating an arc detection apparatus according to an embodiment of the present invention. Specifically, this embodiment relates to signals generated in the arc sensing neglect with the first current processing section 26c described in FIG. 9 uses RMS detectors as the reference signal rectifier 106 and the comparison signal rectifier 100, a low pass filter as the comparison signal filter 102 and the reference signal filter 108, and the comparison A waveform diagram of signals generated in an embodiment using a log amplifier as the signal converter 104 and the reference signal converter 110. According to this embodiment, the cutoff frequency of the comparison signal filter 102 is 250KHz, and the cutoff frequency of the reference signal filter 108 is 10KHz.

FIG. 9A illustrates a waveform of the current signal SI output from the sensing unit 22, and FIG. 9B illustrates a preliminary comparison signal SN1c output from the comparison signal filter 102. And a waveform of the preliminary reference signal RE1c output from the reference signal filter 108, and FIG. 9C shows the first comparison signal IN1c and the combiner output from the comparison signal converter 104. A waveform of the first reference signal REF1c output from 112 is shown, and FIG. 9D shows a waveform of the first arc detection signal OUT1 output from the comparator 42c. 9 (e) shows a waveform output from the output signal DISP1 of the first type arc counter of the arc type determiner 48. For brevity of description, hereinafter, description of contents overlapping with the embodiments described with reference to FIGS. 3 to 5 will be minimized.

Referring to FIG. 9C, the comparison signal converter 104 performs a logarithmic conversion from the preliminary comparison signal SN1c and outputs a first comparison signal IN1c.

Referring to FIG. 9C, the reference signal converter 110 performs a logarithmic conversion from the preliminary reference signal RE1c and outputs a conversion reference signal PR1c. The combiner 112 outputs the first reference signal REF1c by summing the conversion reference signal PR1c and the offset signal OSc generated by the offset signal 114.

The DC biases of the conversion reference signal PR1c and the first comparison signal IN1c have the same magnitude that cannot be distinguished from each other. The combiner 112 adds the offset signal OSc of the offset signal generator 114 and the conversion reference signal PR1c of the reference signal converter 110 to be distinguished from the first comparison signal IN1c. Produce (REF1c). The offset signal OSc may be a negative value.

Referring to FIG. 9D, the comparison unit 42c compares the first comparison signal IN1c and the first reference signal REF1c to detect the first arc detection signal corresponding to the disturbance caused by the arc. Outputs (OUT1). Since the information according to the plasma characteristic is included in both the first comparison signal IN1c and the first reference signal REF1c, the information about the plasma characteristic change is not included in the first arc detection signal OUT1. . However, as described above, since the disturbance component due to the arc is included in the first comparison signal IN1c but not included in the first reference signal REF1c, the first arc detection signal OUT1 is shown. Have pulses a, b, c, d corresponding to the arc generation. Meanwhile, according to an embodiment of the present invention, the width of the pulse d corresponding to the arc generated after the plasma characteristic is changed is the widths of the pulses a, b, and c generated before the plasma characteristic is changed. Can be different from.

10 is a block diagram showing a configuration of a processing unit according to an embodiment of the present invention.

1, 2, and 10, the processor 25 according to this embodiment may be used for any one of the above-described first current processor, second current processor, and voltage processor. The first current processor 26d includes a comparison signal generator 40d, a reference signal generator 44d, and a comparator 42d. The comparison unit 42d compares the first comparison signal IN1d of the comparison signal generator 40d with the first reference signal REF1d of the reference signal generator 44d to compare the first arc detection signal OUT1. )

The comparison signal generator 40d receives the subtractor 92 and the current signal SI to generate a first calculation signal D_IN1d including a disturbance component by an arc. And a second signal calculator 91 that receives the current signal SI and generates a second calculation signal D_IN2d from which the disturbance component due to the arc is removed. The subtractor 92 outputs a difference between these signals as a first comparison signal IN1d from the output signals of the first signal calculator 85 and the second signal calculator 91.

The first signal calculator 85 may include at least one of a first comparison signal rectifier 80, a first comparison signal filter 82, and a first reference signal converter 84. The second signal calculator 91 may include at least one of a second comparison signal rectifier 86, a second comparison signal filter 88, and a second comparison signal converter 90.

The first comparison signal rectifier 80 receives the current signal SI of the detector 22 and outputs a first rectified signal RCT1d. The first comparison signal rectifier 80 may be an RMS detector. The RMS detector outputs a root mean square value of the input signal. The first comparison signal filter 82 removes a driving frequency component of the RF power supply 10 from the first rectified signal RCT1d and outputs a first comparison filter signal SN1d including a disturbing component by an arc.

The first comparison signal converter 84 receives the first comparison filter signal SN1d, converts at least one of an amplitude and a polarity, and outputs the converted first signal as the first calculation signal D_IN1d. The first comparison signal converter 84 may be a log amplifier. The log amplifier outputs a log value of the input signal. The first calculation signal D_IN1d may include plasma characteristic change information and information on a first type arc. In addition, when there is a second type arc, the first calculation signal D_IN1d may include information on generation of the second type arc.

The second comparison signal rectifier 86 receives the current signal SI of the detector 22 and outputs a second rectified signal RCT2d. The second comparison signal rectifier 86 may be an RMS detector. The RMS detector outputs a root mean square value of the input signal. The second comparison signal filter 88 removes the driving frequency component of the RF power supply 10 and the disturbance component by the arc from the second rectified signal RCT2d and outputs the second comparison filter signal SN2d.

The second comparison signal converter 90 receives the second comparison filter signal SN2d and converts at least one of an amplitude and a polarity to generate a second calculation signal D_IN2d. The second comparison signal converter 90 may be a log amplifier. The log amplifier outputs a log value of the input signal. The second calculation signal D_IN2d contains plasma characteristic change information.

The subtractor 92 outputs the difference as the first comparison signal IN1d from the first calculation signal D_IN1d and the second calculation signal D_IN2d. The subtractor 92 may use a differential amplifier. The subtractor 92 may remove information on the DC bias and the plasma characteristic change from the first reference signal IN1d.

The reference signal generator 44d may generate the first reference signal REF1d by processing the current signal SI as described with reference to FIGS. 2 to 5. Alternatively, the reference signal generator 44d may generate the first reference signal REF1d having a predetermined size without processing the current signal SI.

11 is a waveform diagram illustrating an arc detection apparatus according to an embodiment of the present invention. Specifically, this embodiment relates to signals generated in the arc sensing device having the first current processor 26d described with reference to FIG. 10. FIG. 11 shows RMS detectors as the first comparison signal rectifier 80 and the second comparison signal rectifier 86 and a low frequency as the first comparison signal filter 82 and the second comparison signal filter 88. A waveform diagram of signals generated in an embodiment using a pass filter and using a log amplifier as the first comparison signal converter 84 and the second comparison signal converter 90. According to this embodiment, the cutoff frequency of the first comparison signal filter 82 is 250KHz, and the cutoff frequency of the second comparison signal filter 88 is 10KHz.

FIG. 11A illustrates a waveform of the current signal SI output from the sensing unit 22, and FIG. 11B illustrates a first comparison filter output from the first comparison signal filter 82. A waveform of the second comparison filter signal SN2d output from the signal SN1d and the second comparison signal filter 88 is shown, and FIG. 11C illustrates that the waveform is output from the first comparison signal converter 84. A first calculation signal D_IN1d and a second calculation signal D_IN2d output from the second comparison signal converter 90 are shown, and FIG. 11D illustrates a first output from the subtractor 92. A waveform of the comparison signal IN1d and the first reference signal REF1d output from the reference signal generator 44 is shown, and FIG. 11E illustrates a first arc detection signal output from the comparison unit 42. A waveform of OUT1 is shown, and FIG. 11F shows a wave of the output signal DISP1 of the first type arc counter output from the arc type determiner 48. Show.

Referring to FIG. 11B, the first comparison signal filter 82 removes a driving frequency component of the RF power supply 10 from the output signal RCT1d of the first comparison signal rectifier 80 but does not apply an arc to the arc. Generate a first comparison filter signal SN1d including a disturbance component. However, the first comparison filter signal SN1d contains plasma characteristic change information (t3 to t4 section) and information about the first type arc (A, B, C, D). In addition, when there is a second type arc, the first comparison filter signal SN1d may include information on generation of a second type arc.

Referring to FIG. 11B, the second comparison signal rectifier 86 outputs an average root mean value RCT2d from the current signal SI, and the second comparison signal filter 88 outputs the mean root mean square value. The RCT2d is input to remove and output a driving frequency component of the RF power supply 10 and a disturbing component by the arc. The output signal SN2b of the second comparison signal filter 88 may include plasma characteristic change information (t3 to t4 section).

Referring to FIG. 11C, the first reference signal converter 84 generates a first calculation signal D_IN1d obtained by converting the first comparison filter signal SN1d into a log value. Referring to FIG. 11C, the second comparison signal converter 90 generates a second calculation signal D_IN2 obtained by converting the second comparison filter signal SN2d into a log value.

Referring to FIG. 11D, the subtractor 92 subtracts the second calculation signal D_IN2d from the first calculation signal D_IN1d and outputs a first comparison signal IN1d. That is, as a result of employing the log amplifier and the subtractor 92, the first comparison signal IN1d may log a ratio between the first reference filter signal SN1d and the second reference filter signal SN2d. The signal is converted into. Therefore, the first comparison signal IN1d has no DC bias and no change in DC bias due to the plasma characteristic change. In addition, since the first comparison signal IN1d depends on the ratio, the first reference signal REF1d which is an output signal of the reference signal generator 44d may be set to a constant value. That is, the first reference signal REF1d may be set to a constant value, not from the current signal SI.

12 is a block diagram showing a configuration of a processing unit according to an embodiment of the present invention.

1, 2, 8, and 12, the processor 25 according to this embodiment may include a first current processor 26 and a second current processor 28. In addition, the processor 25 may further include a voltage processor. The voltage processor may have the same configuration as the first current processor or the second current processor. The first current processor 26 and the second current processor 28 may have the same configuration as described with reference to FIG. 8. The processor 25 includes a comparison signal generator 40, a reference signal generator 44, and a comparator 42.

The first current processor 26 includes a first comparison signal generator 40e, a first reference signal generator 44e, and a first comparator 42e. The first comparison signal generator 40e may include at least one of a first comparison signal rectifier 100e, a first comparison signal filter 102e, and a first comparison signal converter 104e. The first reference signal generator 44e includes a first reference signal rectifier 106e, a first reference signal filter 108e, a first reference signal converter 110e, a first combiner 112e, and a first offset signal. It may include at least one of (114e). The comparison unit 42e compares the first comparison signal IN1e and the first reference signal REF1e and outputs a first arc detection signal OUT1.

The second current processor 28 includes a second comparison signal generator 40f, a second reference signal generator 44f, and a second comparator 42f. The second comparison signal generator 40f may include at least one of a second comparison signal rectifier 100f, a second comparison signal filter 102f, and a second comparison signal converter 104f. The second reference signal generator 44f includes a second reference signal rectifier 106f, a second reference signal filter 108f, a second reference signal converter 110f, a second combiner 112f, and a second offset signaler. It may include at least one of (114f). The second comparator 42f compares the second comparison signal IN2f and the second reference signal REF2f to output a second arc detection signal OUT2.

The post-processing unit 32 described with reference to FIG. 2 receives the first and second arc detection signals OUT1 and OUT2 to measure the pulse width. If it is determined that the type arc counter signal DISP1 is the second type arc, the arc type determiner 48 outputs the second type arc signal DISP2. When the processing unit 25 has only the first current processing unit 26 and the second current processing unit 28, the determination of the arc type is not compared with the third arc detection signal of the voltage processing unit 30. The arc type may be determined based on the signs of the second arc detection signals OUT1 and OUT2.

1 and 12, the processor 25 may have a first current processor 26, a second current processor 28, and a voltage processor. The voltage processor may have the same configuration as the first current processor 26. The voltage processor may output the third arc detection signal OUT3 by receiving the voltage signal SV and comparing the voltage comparison signal and the voltage reference signal. The first current processor 26 may have the same configuration as the second current processor 28 and the voltage processor. If the sign of the first arc detection signal OUT1 or the second arc detection signal OUT2 and the sign of the third arc detection signal OUT3 are different from each other, the second arc detection signal OUT2 is determined as the second type arc. If the sign of the first arc detection signal OUT1 or the second arc detection signal OUT2 and the sign of the third arc detection signal OUT3 are the same, the first arc detection signal OUT1 is determined as the first type arc.

13 is a waveform diagram illustrating an arc detection apparatus according to an embodiment of the present invention. Specifically, this embodiment relates to signals generated in the arc sensing device having the first and second current processing units described in FIG. 12. FIG. 13 illustrates that the first and second reference signal rectifiers 106e and 106f and the first and second comparison signal rectifiers 100e and 100f use an RMS detector, and the first and second comparison signal filters 102e, 102f) and a low pass filter as the first and second reference signal filters 108e and 108f, and the first and second comparison signal converters 104e and 104f and the first and second reference signal converters ( 110e and 110f are waveform diagrams of signals generated in the embodiment using the log amplifier. According to this embodiment, the cutoff frequencies of the first and second comparison signal filters 102e and 102f are 250KHz, and the cutoff frequencies of the first and second reference signal filters 108e and 108f are 10KHz.

FIG. 13A shows a waveform of the current signal SI output from the sensing unit 22, and FIG. 13B shows the first and second comparison signal filters 102e and 102f and Waveforms of the first and second preliminary comparison signals SN1e and SN2f and the first and second preliminary reference signals RE1e and RE2f respectively output from the first and second reference signal filters 108e and 108f, FIG. 13C shows the first and second comparison signals IN1e and IN2f and the first and second combiners 112e and 112f respectively output from the first and second comparison signal converters 104e and 104f, respectively. The waveforms of the first and second reference signals REF1e and REF2f are output, and FIG. 13D illustrates the first and second arc detection signals OUT1 output from the first and second comparators 42e and 42f. , FIG. 13E shows waveforms of the output signal DISP1 and the second type arc signal DISP2 of the first type arc counter output from the arc type determiner 48.

Referring to FIG. 13A, the detector 22 outputs a current signal SI obtained by measuring a current flowing through a transmission line. The current signal SI may include information according to a characteristic change of the plasma in addition to the information according to the arc. The current signal SI caused by the first type arcs A, B, C, and D rapidly decreases and returns to its original state. The current signal SI according to the second type arc F increases and decreases in amplitude to reach a steady state. The time interval t2-t1 of the change of the current signal SI due to the first type arc may be shorter than the time interval t6-t5 of the change of the current signal SI due to the second type arc.

Referring to FIG. 13B, the first and second comparison signal filters 102e and 102f include components for disturbance component and plasma characteristic change due to arc, but the first and second components are removed from the driving frequency component. Two preliminary comparison signals SN1e and SN2f are generated. The first and second preliminary comparison signals SN1e and SN2f have information about the first type arcs A, B, C, and D, and information about the second type arc F. As shown in FIG. Meanwhile, the first and second reference signal filters 108e and 108f generate first and second preliminary reference signals RE1e and Re2f from which the disturbance component and the driving frequency component by the arc are removed. However, when there is a change in plasma characteristics, the first and second preliminary reference signals RE1e and Re2f may be different from the first and second preliminary comparison signals SN1e and SN2f.

Referring to FIG. 13C, the first and second combiners 112e and 112f may include the first and second offset signals OSe and OSf of the first and second offset signals 114e and 114f. The first and second reference signals REF1e and REF2f are generated by adding the output signals of the first and second reference signal converters 110e and 110f, respectively. The offset signal OSe of the first current processor 26 may be a negative value. However, the first offset signal OSe of the first current processor 26 and the second offset signal OSf of the second current processor 28 may be different. That is, the second offset signal OSf of the second current processor 28 may be a positive value in order to detect the current signal SI of the second type arc.

Referring to FIG. 13D, the first comparator 42e of the first current processor 26 compares the first comparison signal IN1e with the first reference signal REF1e to detect the first arc detection signal. Outputs (OUT1). In the case of the first type arcs A, B, C, and D, the comparing unit 42e outputs the first arc detection signal OUT1. However, when the second type arc F is generated and the amplitude of the current signal increases, the comparison unit 42e does not cross the first reference signal REF1e and the first comparison signal IN1e. It does not detect the second type arc (F).

Referring to FIG. 13D, the second comparator 42f of the second current processor 28 compares the second comparison signal IN2f with the second reference signal REF2f to detect the second arc detection signal. Outputs (OUT2). In the case of the first type arcs A, B, C, and D, since the second reference signal REF2f and the second comparison signal IN2f do not cross each other, the second comparator 42f includes the first The arc detection signal cannot be output. However, when the second type arc F is generated and the amplitude of the current signal SI is increased, the second comparator 42f detects this and outputs the second arc detection signal OUT2.

 Referring to FIG. 13E, the post processor 32 described with reference to FIG. 2 receives the first and second arc detection signals OUT1 and OUT2 to measure a pulse width, and when determined as a first type arc, The arc type determiner 48 outputs the first type arc counter signal DISP1, and if it is determined that it is the second type arc, the arc type determiner 48 outputs the second type arc signal DISP2. .

4 is a flowchart illustrating an arc detection method according to embodiments of the present invention. The arc sensing method described below may be implemented through the arc sensing apparatus described above with reference to FIGS. 1 to 3.

Referring back to FIG. 4, the arc sensing method according to the present invention measures an electrical signal of a current or voltage of a transmission line connected to a load (S10), and processes the electrical signal to correspond to the occurrence of an arc at the load. Generating at least one arc detection signal (S20), analyzing the arc detection signal to determine whether an arc occurs in the load (32), and analyzing the arc detection signal to arc type at the load Determining (34).

In this case, the generating of the arc detection signal (S20) may include generating a reference signal from the electrical signal (S22), generating a comparison signal from the electrical signal (S24), and comparing the reference and comparison signals. Generating the arc detection signal (S26). The reference signal, the comparison signal and the arc detection signal may be generated through the method described with reference to FIGS. 1 to 3. Similarly, the determination of whether the arc is generated and the type of the arc may be made through the method described with reference to FIGS. 1 to 3.

Generating the reference signal (S22) may include removing the disturbing component by the arc from the electrical signal. Removing the disturbing component by the arc may include removing a component of a first frequency band from the electrical signal, wherein the first frequency band may include a frequency band due to the disturbing component by the arc. have. The frequency band due to the disturbance component by the arc may be in the range of 10 KHz to 250 KHz. Removing the components of the first frequency band may use a low pass filter or a band pass filter (as described with reference to FIG. 4). However, the driving frequency component of the RF power source may be removed in the generating of the reference signal.

The generating of the reference signal (S22) may include at least one of rectifying the electrical signal, removing a disturbance component due to an arc from the electrical signal, and changing an amplitude or polarity of the electrical signal. It may include.

Generating the comparison signal (S24) may include extracting a disturbing component by an arc from the electrical signal. Extracting the disturbance component by the arc may include removing a component of a second frequency band from the electrical signal. The second frequency band may not include the frequency band due to the disturbing component by the arc. The frequency band due to the disturbance component by the arc may be in the range of 10 KHz to 250 KHz. However, the driving frequency component of the RF power source may be removed in the step of generating the comparison signal.

The generating of the comparison signal (S24) may include at least one of rectifying the electrical signal, extracting a disturbance component due to an arc from the electrical signal, and changing an amplitude or polarity of the electrical signal. It may include. In order to compare the reference signal and the comparison signal with each other, the amplitude or polarity of the signals may be changed or the signals may be offset.

Comparing the reference signal with the comparison signal (S26) may include comparing a reference signal from which the disturbance component due to the arc is removed and a comparison signal including the disturbance component due to the arc. In the comparing step S26, a difference between the reference signal and the comparison signal may be detected. The comparator may output a difference between the comparison signal and the reference signal as a positive or negative signal. The comparing may be determined by a logic calculator by converting the comparison signal and the reference signal into a digital signal. In the comparing step S26, the arc detection signal may generate a pulse proportional to the duration of the arc.

The arc generation determining step S32 may include analyzing the width of the at least one arc detection signal to determine whether the arc occurs at the load. The width of the signal can be calculated using a logic operator.

In the determining of the arc generation (S32), when the width of the arc detection signal is within a first reference width to a second reference width, it may be determined as an arc. The first reference width may be 4 usec. The second reference width may be 100 usec. When the first reference width is within the second reference width, it is determined that an arc has occurred in the load, and when the second reference width is exceeded, it may be regarded as a characteristic change of plasma, and when it is less than the first reference width, it may be determined as noise. Can be.

Determining the type of the arc (S34) includes at least one current arc detection signal obtained by measuring the current flowing through the transmission line, and at least one voltage arc detection signal obtained by measuring the voltage of the transmission line.

The determining of the arc type (S34) may include determining the type of arc generated in the load by analyzing the polarity of the current arc detection signal and the current arc detection signal. The determining of the arc type (S34) may include determining that a second type arc is generated in the load when the change polarities of the current arc detection signal and the voltage arc detection signals are different from each other. When the change polarities of the voltage arc detection signals are the same, it may be determined that the first type arc is generated in the load.

According to a modified embodiment of the present invention, the determining of the arc type may be determined as a first type arc if the sign of the current arc detection signal is a negative value, and a second type arc if it is a positive value. Can be.

The present invention measures the electrical signal of the current and voltage of the transmission line. As a result, it is possible to distinguish between arc, plasma characteristic change, and noise, to be easily installed in the discharge system, to distinguish between type 1 arc and type 2 arc, and real time monitoring is possible. Therefore, it is possible to determine whether there is an abnormality in the plasma treatment step at an early stage.

Claims (24)

A transmission line connected to the plasma generating device and transmitting an electrical signal of a current and a voltage of a radio frequency (RF); A detector for measuring an electrical signal of a current and a voltage of the transmission line; A processor including a current processor configured to process the electrical signal of the current to generate at least one current arc detection signal, and a voltage processor to process the electrical signal of the voltage to generate at least one voltage arc detected signal; And An arc generation determiner for determining whether an arc is generated in the plasma generation device by analyzing the durations of the current arc detection signal and the voltage arc detection signal corresponding to the arc generated in the plasma generation device, and the current and voltage Including a post-processing unit including an arc type determiner to determine the type 1 arc and the type 2 arc according to the change tendency of the electrical signal of, The sensing unit includes at least one sensor disposed around the transmission line, The sensor includes a current meter for measuring the current flowing through the transmission line and a plasma abnormality detection device including a voltage meter for measuring the voltage of the transmission line. According to claim 1, And the duration of the current arc detection signal and the voltage arc detection signal is greater than a period of the radio frequency. delete The method according to claim 1 or 2, The current processor is configured to be connected to the current meter to generate the current arc detection signal from a current signal of the transmission line, And the voltage processor is coupled to the voltage meter to generate the voltage arc detection signal from the voltage signal of the transmission line. The method according to claim 1 or 2, The current processing unit At least one reference signal generator configured to generate a reference signal for generating the current arc detection signal; At least one comparison signal generator for converting the electrical signal into a comparison signal for comparison with the reference signal; And At least one comparison unit comparing the reference signal with the comparison signal to generate the current arc detection signal; The voltage processor At least one reference signal generator configured to generate a reference signal for generating the voltage arc detection signal; At least one comparison signal generator for converting the electrical signal into a comparison signal for comparison with the reference signal; And And at least one comparator configured to generate the voltage arc detection signal by comparing the reference signal with the comparison signal. The method of claim 5, wherein The reference signal generator includes at least one of a reference signal rectifier for rectifying the electrical signal, a reference signal filter for removing a disturbance component caused by the arc of the electrical signal, and a reference signal converter for changing the amplitude or polarity of the electrical signal. Plasma abnormality detection device characterized in that. The method of claim 6, The reference signal generator is An offset signal generator for generating an offset signal; And And a combiner for combining the offset signal and the electrical signal output from the reference signal converter, And said combiner is one of an adder or a subtractor. The method of claim 5, The comparison signal generator includes at least one of a comparison signal rectifier for rectifying the electrical signal, a comparison signal filter including a disturbing component by an arc of the electrical signal, and a comparison signal converter for changing the amplitude or polarity of the electrical signal. Plasma abnormality detection device characterized in that. The method of claim 8, The comparison signal filter is configured to extract a disturbing component by an arc from the electrical signal rectified in the comparison signal rectifier, And the comparison signal converter is configured to change an amplitude or a polarity of the electrical signal filtered by the comparison signal filter. The method of claim 5, The comparison signal generator for generating the comparison signal includes a subtractor, a first signal calculator and a second signal calculator, The first signal calculator includes a first comparison signal rectifier for rectifying the electrical signal, a first comparison signal filter including a disturbing component due to an arc of the electrical signal, and a first comparison signal converter for changing the amplitude or polarity of the electrical signal. At least one of The second signal calculator includes a second comparison signal rectifier for rectifying the electrical signal, a second comparison signal filter for removing a disturbance component due to arc of the electrical signal, and a second comparison signal converter for changing the amplitude or polarity of the electrical signal. At least one of And the subtractor outputs a difference between these signals as a comparison signal from the output signals of the first signal calculator and the second signal calculator. The method of claim 4, wherein The current processor includes a first current processor, and a second current processor, The first current processor may include a first current processor configured to generate a first current arc detection signal by processing a current signal among the electrical signals; The second current processor may include a second current processor configured to generate a second current arc detection signal by processing a current signal among the electrical signals; And And the voltage processor is configured to process a voltage signal among the electrical signals to generate a voltage arc detection signal. The method of claim 5, The comparison unit is configured to compare the reference signal and the comparison signal to generate the current and voltage arc detection signal generated corresponding to the arc generated in the plasma generating apparatus, And the current and voltage arc detection signal has a width corresponding to the duration of the arc in the plasma generating device. delete Measuring an electrical signal of a current and a voltage of a radio frequency (RF) transmitted along a transmission line connected to the plasma generating device; The current arc detection signal corresponding to the arc generation in the plasma generating apparatus is processed by processing the electrical signal of the current, and the voltage arc detection signal corresponding to the arc generation in the plasma generating apparatus is generated by processing the electrical signal of the voltage. Making; Analyzing the duration of the current and voltage arc detection signals to determine arc generation in the plasma generator; And And determining the first type arc and the second type arc according to the change tendency of the current and voltage arc detection signals and the electrical signals of the current and voltage. And the duration of the duration of the current and voltage arc detection signal is greater than the period of the radio frequency (RF). The method of claim 14, The electrical signal is measured continuously in real time, Generating the current and voltage arc detection signal, determining the arc generation, and determining the first type arc and the second type arc, the information on the arc generation in the plasma generating apparatus in real time And processing the electrical signal of the transmission line in real time to provide. The method of claim 14, Generating the current and voltage arc detection signal Generating at least one reference signal; Generating at least one comparison signal using the measured electrical signal of the transmission line; And And comparing the reference signal with the comparison signal to generate a current and voltage arc detection signal. The method of claim 16, Generating the reference signal includes removing a disturbing component due to an arc from the electrical signal, The generating of the comparison signal includes extracting a disturbance component due to an arc from the electrical signal. The generating of the arc detection signal includes comparing the reference signal from which the disturbance component by the arc is removed and a comparison signal including the disturbance component by the arc. The method of claim 17, Generating the reference signal includes removing a component of a first frequency band from the electrical signal, And said first frequency band comprises a frequency band of a disturbance component caused by said arc. The method of claim 17, Generating the comparison signal includes removing a component of a second frequency band from the electrical signal, And the second frequency band does not include a frequency band of a disturbance component caused by the arc. The method of claim 16, The generating of the reference signal includes at least one of rectifying the electrical signal, removing a disturbance component due to an arc from the electrical signal, and changing an amplitude or polarity of the electrical signal. The generating of the comparison signal includes at least one of rectifying the electrical signal, extracting a disturbance component due to an arc from the electrical signal, and changing an amplitude or polarity of the electrical signal. A plasma abnormality detection method characterized by the above-mentioned. The method of claim 14, The determining of the arc generation comprises the step of analyzing the width of the current and voltage arc detection signal to determine whether the arc occurs in the plasma generating apparatus. The method of claim 14, The determining of the arc type includes analyzing the polarity of the current arc detection signal and the voltage arc detection signal, and determining the type of arc generated in the plasma generating device. . The method of claim 22, Determining the type of arc If the change polarities of the current arc detection signal and the voltage arc detection signals are the same, the corresponding arc detection signal is determined as a result of the first type arc, And if the change polarities of the current arc detection signal and the voltage arc detection signals are different, determine the arc detection signal as a result of the second type arc. The method of claim 22, Determining the type of arc If the sign of the current arc detection signal is a negative value, it is determined as a first type arc, and if it is a positive value, it is determined as a second type arc.

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