Non-contact plasma monitoring method and non-contact plasma monitoring apparatus using same

Abstract

The invention discloses a non-contact plasma monitoring method and a non-contact plasma monitoring apparatus using the same. The non-contact plasma monitoring method includes: a first step of disposing one or more RF sensors outside an inductively coupled plasma generator including an antenna, and respectively measuring induced electromotive forces induced by the RF sensors as a function of time through the antenna; a second step of performing Fourier transform on the function of the induced electromotive force per time, and then deriving amplitude values of n-order harmonics; and a third step of deriving the state of the plasma in the plasma generator from the amplitude value of each n-order harmonic.

Description

Technical Field

[0001] The invention relates to a non-contact plasma monitoring method and a non-contact plasma monitoring device using the method. Background Art

[0002] When operating a plasma generator, a method of directly setting a diagnostic device in the plasma reactor is used to measure the plasma state such as the electron density or electron temperature of the plasma. In this case, contamination of the diagnostic device occurs depending on the process conditions. In addition, when the diagnostic device is applied during the process, there is a possibility that the stability of the process is reduced and impurities are introduced. Therefore, a method of measuring the plasma state outside the plasma generator is required. Summary of the invention

[0003] An object of the present invention is to provide a non-contact plasma monitoring method, which can measure the plasma state without providing a diagnostic device inside a plasma reactor.

[0004] Another object of the present invention is to provide a non-contact plasma monitoring device for implementing the non-contact plasma monitoring method.

[0005] According to one aspect, the present invention provides a non-contact plasma monitoring method, which includes: a first step, configuring one or more RF sensors outside an inductively coupled plasma (ICP) generator including an antenna, and measuring the induced electromotive force induced to the RF sensor through the antenna as a function of time; a second step, after Fourier transforming the function of the induced electromotive force per time, deriving the amplitude value of the nth harmonic respectively; and a third step, deriving the state of the plasma in the plasma generator from the amplitude value of each nth harmonic. Here, n is a natural number greater than or equal to 1.

[0006] The non-contact plasma monitoring method of the present invention can monitor the plasma state from outside the plasma generator through the above steps.

[0007] In one embodiment, the antenna may be formed on at least one plane of the inductively coupled plasma generator. In one embodiment, the antenna may be formed on an upper plane of the inductively coupled plasma generator. In one embodiment, the antenna may be formed in a spiral shape on an upper plane of the inductively coupled plasma generator. In one embodiment, each of the RF sensors may be configured outside the antenna. In one embodiment, each of the RF sensors may be configured such that the plane formed by each of the RF sensors is perpendicular to the plane on which the antenna is formed. In one embodiment, each of the RF sensors may be configured such that the plane formed by each of the RF sensors is perpendicular to the plane formed by the spiral antenna.

[0008] By arranging the RF sensor as described above, an induced electromotive force can be induced from the antenna to the RF sensor.

[0009] In one embodiment, the n is 1, and in the third step (S130), after deriving the linear proportional relationship between the plasma electron density directly measured inside the plasma generator and each amplitude value, the unknown plasma electron density can be derived from the amplitude value measurement result through the linear proportional relationship.

[0010] In one embodiment, more than two RF sensors may be configured in the first step. In one embodiment, the antenna may be formed in a spiral shape on an upper plane of the inductively coupled plasma generator. In one embodiment, the more than two RF sensors may be configured so that radial distances in the spiral formed by the antennas are different from each other. In one embodiment, by deriving the plasma electron density from each RF sensor in the third step, the distribution of the unknown plasma electron density may be derived.

[0011] In an embodiment, each of the RF sensors may be configured to be located on the antenna.

[0012] In one embodiment, in the third step, whether impurities are introduced into the plasma is confirmed by whether the amplitude value change of the nth harmonic exceeds a preset level. In one embodiment, n can be 5 or 6.

[0013] According to another aspect, the present invention provides a non-contact plasma monitoring device, which includes: a sensor unit, including: one or more RF sensors; and a recording unit, which can measure the induced electromotive force sensed by each RF sensor and record the function according to time; and a monitoring unit, including: a calculation unit, which can perform Fourier transform on the function of each induced electromotive force according to the recorded time; and an output unit, which derives the state of plasma from each Fourier transform result of the calculation unit through the amplitude value of the nth harmonic. The n can be a natural number greater than or equal to 1.

[0014] The above-described device can ensure the stability of the plasma by monitoring the state of the plasma outside the plasma generator.

[0015] In one embodiment, the non-contact plasma monitoring device can monitor the plasma in an inductively coupled plasma generator having an antenna formed on at least one plane. In one embodiment, the non-contact plasma monitoring device can monitor the plasma in an inductively coupled plasma generator having an antenna formed on an upper plane. In one embodiment, the non-contact plasma monitoring device can monitor the plasma in an inductively coupled plasma generator having a spiral antenna formed on an upper plane. In one embodiment, each of the RF sensors can be formed to be arranged outside the antenna. In one embodiment, each of the RF sensors can be formed so that the plane formed by each of the RF sensors is perpendicular to the plane on which the antenna is formed. In one embodiment, each of the RF sensors can be formed so that the plane formed by each of the RF sensors is perpendicular to the plane on which the spiral antenna is formed.

[0016] By configuring the RF sensor as described above, the RF sensor in the device can generate an induced electromotive force from the antenna.

[0017] In one embodiment, n is 1, and after deriving the linear proportional relationship between the plasma electron density directly measured inside the plasma generator and each amplitude value, the output unit can derive the unknown plasma electron density from the amplitude value measurement result through the linear proportional relationship.

[0018] In one embodiment, the sensor unit may include more than two RF sensors. In one embodiment, the antenna may be formed in a spiral shape on an upper plane of the inductively coupled plasma generator. In one embodiment, the more than two RF sensors may be configured so that radial distances in the spiral formed by the antennas are different from each other. In one embodiment, the output unit may derive the distribution of unknown plasma electron density by deriving the plasma electron density from each of the RF sensors.

[0019] In an embodiment, one or more of the RF sensors may be configured to be located on the antenna.

[0020] In one embodiment, the output unit confirms whether impurities are introduced into the plasma by determining whether the amplitude of the nth harmonic changes beyond a preset level. In one embodiment, n may be 5 or 6.

[0021] Effects of the Invention

[0022] According to the non-contact plasma monitoring device of the embodiment of the present invention, the plasma state, including the plasma electron density and impurities, can be monitored from the outside of the plasma, thereby ensuring the stability of the plasma.

[0023] According to the non-contact plasma monitoring apparatus of the embodiment of the present invention, by implementing the non-contact plasma monitoring method, the plasma state can be monitored while maintaining the stability of the plasma. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart illustrating a non-contact plasma monitoring method according to an embodiment of the present invention.

[0025] Figure 2 The structure of a non-contact plasma monitoring device according to an embodiment of the present invention is shown.

[0026] Figure 3 FIG. 1 is a diagram showing an example of a method of arranging a plurality of RF sensors when the non-contact plasma monitoring apparatus according to the embodiment of the present invention includes two or more RF sensors.

[0027] Figures 4 to 9 is a graph showing the results of an experimental example according to the present invention. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The present invention can be modified in many ways and can have many forms, so specific embodiments are illustrated in the drawings and described in detail in this specification. However, it should be understood that this does not limit the present invention to a specific disclosure method, but includes all modifications, equivalent technical solutions and alternative solutions included in the concept and technical scope of the present invention. When describing the drawings, similar components are marked with similar reference numerals.

[0029] The terms used in this application are only used to illustrate specific embodiments and are not intended to limit the present invention. Unless the context clearly indicates a different meaning, a singular expression includes a plural expression. In this application, terms such as "including" or "having" are used to specify the existence of features, steps, actions, constituent elements, parts, or combinations thereof recorded in the specification, and shall not be understood as excluding in advance the existence or additional possibility of one or more other features or steps, actions, constituent elements, parts, or combinations thereof.

[0030] Unless otherwise defined, all terms used in this application, including technical and scientific terms, have the same meaning as commonly understood by those skilled in the art to which the invention belongs. Terms defined in commonly used dictionaries should be interpreted as having the same meaning as that in the context of the relevant art, and, unless explicitly defined in this application, should not be interpreted in an idealized or overly formalized sense.

[0031] Figure 1 is a flow chart illustrating a non-contact plasma monitoring method according to an embodiment of the present invention.

[0032] Reference Figure 1 According to the non-contact plasma monitoring method of an embodiment of the present invention, a non-contact plasma monitoring method is provided, which includes: a first step (S110), configuring one or more RF sensors outside an inductively coupled plasma (ICP) generator including an antenna, and measuring the induced electromotive force induced to the RF sensor through the antenna as a function of time; a second step (S120), after Fourier transforming the function of the induced electromotive force per time, deriving the amplitude value of the nth harmonic respectively; and a third step (S130), deriving the state of the plasma in the plasma generator from the amplitude value of each nth harmonic. Here, n is a natural number greater than or equal to 1. The non-contact plasma monitoring method of the present invention can monitor the plasma state from the outside of the plasma generator through the above steps.

[0033] The first step (S110) is a step of measuring the induced electromotive force generated from the plasma generator, especially measuring the function of time. The plasma generator, especially the inductively coupled plasma generator, may include an antenna, and plasma may be generated inside the plasma generator by applying a current to the antenna and a change in the current, and a change in the surrounding magnetic field may occur from the antenna, so when the RF sensor is configured around the antenna, an induced electromotive force may be induced to the RF sensor from the change in the magnetic field. Therefore, the RF sensor may be configured at a position and direction where an induced electromotive force may be induced from the antenna. In one embodiment, the antenna may be formed on at least one plane of the inductively coupled plasma generator. In one embodiment, the antenna may be formed on an upper plane of the inductively coupled plasma generator. In one embodiment, the antenna may be formed in a spiral shape on an upper plane of the inductively coupled plasma generator. In one embodiment, each RF sensor may be configured outside the antenna. In one embodiment, each RF sensor may be configured so that the plane formed by each RF sensor is perpendicular to the plane on which the antenna is formed. In one embodiment, each of the RF sensors may be configured so that a plane formed by each of the RF sensors is perpendicular to a plane formed by the helical antenna. By arranging the RF sensors as described above, an induced electromotive force may be induced from the antenna to the RF sensors.

[0034] The second step (S120) is a process of performing Fourier transform from a function of time according to the induced electromotive force. As is well known in the art, Fourier transform can decompose the function of time into frequency components, and number them in the order of first harmonic, second harmonic from the most important frequency. That is, in the context of this specification, harmonic is the result of Fourier transform, and the nth harmonic refers to the nth harmonic of the frequency component that appears as a result of Fourier transform in the main order, and the amplitude value of the nth harmonic refers to the amplitude value of the above harmonic. In the second step (S120), Fourier transform is performed from the function of time of the induced electromotive force to separate each frequency component, and the amplitude value of each frequency component or a specific nth harmonic is derived.

[0035] The third step (S130) is a step in which information about the plasma state can be extracted from the amplitude value derived in the second step (S120). The amplitude value of the nth harmonic is derived in the second step (S120), and according to the value of n, how close it is to the main frequency component of the induced electromotive force as a function of time can be determined. Therefore, through the combination of the second step (S120) and the third step (S130), according to the non-contact plasma monitoring method of an embodiment of the present invention, a specific plasma state can be derived.

[0036] In one embodiment, the n is 1, and in the third step (S130), a linear proportional relationship between the plasma electron density directly measured inside the plasma generator and each of the amplitude values ​​is derived, and then the unknown plasma electron density is derived from the amplitude value measurement result through the linear proportional relationship. The method of direct measurement inside the plasma generator can be to use a probe for measurement. As described above, the method of directly measuring the plasma electron density inside the plasma generator is a prior art, which has the disadvantage of affecting the plasma electron density. According to the non-contact plasma monitoring method of an embodiment of the present invention, it is found that the plasma electron density measured using the prior art as described above and the amplitude value of the first harmonic of the Fourier transform result of the induced electromotive force as a function of time derived in the second step (S120) and the third step (S130) have a linear proportional relationship. In one embodiment, the non-contact plasma monitoring method of an embodiment of the present invention can be calibrated by the existing direct measurement method.

[0037] The above method is related to the relative positional relationship between the RF sensor and the antenna and the electron density of the point to be measured. Therefore, when more than two RF sensors are used, the plasma electron density can be measured at multiple points. Thereby, the unknown electron density distribution can be measured. In one embodiment, more than two RF sensors can be configured in the first step (S110). In one embodiment, the more than two RF sensors can be configured so that the radial distances in the spiral formed by the antenna are different from each other. In one embodiment, by deriving the plasma electron density from each RF sensor in the third step (S130), the distribution of unknown plasma electron density can be derived.

[0038] The RF sensor is disposed around the antenna, especially on the upper part of the antenna, and there is no particular limitation as long as the position can induce an induced electromotive force. In one embodiment, each of the RF sensors can be disposed on the antenna.

[0039] Measuring the electron density of plasma or the electron density distribution of plasma as described above is only one embodiment of the plasma state that can be derived by the non-contact plasma monitoring method according to an embodiment of the present invention, and the type of plasma state is not particularly limited because the above method can derive correlations with other plasma states measured by the prior art.

[0040] In one embodiment, the third step (S130) can confirm whether impurities are introduced into the plasma by whether the amplitude value change of the nth harmonic exceeds a preset level. In one embodiment, n can be 5 or 6.

[0041] As described above, the non-contact plasma monitoring device according to the embodiment of the present invention can monitor the plasma state, including the plasma electron density and the presence of impurities, from outside the plasma, thereby ensuring the stability of the plasma.

[0042] Figure 2 The structure of a non-contact plasma monitoring device according to an embodiment of the present invention is shown.

[0043] Reference Figure 2 According to the non-contact plasma monitoring device of an embodiment of the present invention, a non-contact plasma monitoring device 1 is provided, comprising: a sensor unit 10, having: one or more RF sensors 11; and a recording unit 12, which can measure the induced electromotive force sensed by each RF sensor 11 and record the function according to time; and a monitoring unit 20, having: a calculation unit 21, which can perform Fourier transform on the function of each induced electromotive force according to the recorded time; and an output unit 22, which derives the state of plasma from each Fourier transform result of the calculation unit 21 through the amplitude value of the nth harmonic. Here, the n can be a natural number greater than or equal to 1. The device as described above can ensure the stability of the plasma by monitoring the state of the plasma outside the plasma generator.

[0044] The non-contact plasma monitoring device according to an embodiment of the present invention is an embodiment of a device that can implement the above-mentioned non-contact plasma monitoring method, and the same or similar terms as those used in the detailed description of the non-contact plasma monitoring method are equally or similarly applicable to the same or similar components of the non-contact plasma monitoring device of the embodiment of the present invention.

[0045] The RF sensor 11 is a member capable of sensing an induced electromotive force from a plasma generator or a part of a structure of a plasma generator. In the context of this specification, an RF sensor is a device capable of sensing a signal having a radio frequency (RF), and as an example, may include a coil. In the context of this specification, a coil is a wire component formed by a conductor to form one or more closed surfaces, and refers to a wire that, when a magnetic field passing through the closed surface formed by the conductor changes, induces an electromotive force so that a current can flow on the conductor.

[0046] The RF sensor 11 may include more than one. In one embodiment, the RF sensor 11 may include one. In another embodiment, the RF sensor 11 may include more than one.

[0047] The recording unit 12 is a device capable of measuring and recording the induced electromotive force sensed to the RF sensor 11. The induced electromotive force can be recorded as a function of time, so the recording unit 12 may also include a separate storage device. In one embodiment, the recording unit 12 may directly measure the induced electromotive force. In another embodiment, the recording unit 12 measures the induced electromotive force by calculating the electromotive force after measuring a physical quantity such as current instead of the induced electromotive force. In this case, the recording unit 12 may also include other computing devices.

[0048] The operation unit 21 can perform Fourier transform on the induced electromotive force measured and recorded by the recording unit 12 as a function of time to identify component frequencies and derive the amplitude value of each frequency. In one embodiment, the operation unit 21 can derive the amplitude value of the nth harmonic as the Fourier transform result.

[0049] The output unit 22 can derive the plasma state from the information about the component frequency derived by the operation unit 21, in particular the amplitude value of the nth harmonic. In one embodiment, the method by which the output unit 22 derives the plasma state is associated with the correlation between the specific plasma state measured by the prior art and the information about the component frequency derived by the operation unit 21, in particular the amplitude value of the nth harmonic, and in particular, calibration is derived through linear correlation.

[0050] Continue to refer to Figure 2 The computing unit 21 and the output unit 22 are shown as separate components, but this is only an example for explaining the functions. When the purpose of the present invention can be achieved and all the functions of the computing unit 21 and the output unit 22 can be achieved, the computing unit 21 and the output unit 22 can be integrated into one component. In one embodiment, the computing unit 21 and the output unit 22 can be integrated into one computing device.

[0051] Reference Figure 2 The recording unit 12 and the monitoring unit 20 are shown as separate components, but this is only an example for explaining the functions. When the purpose of the present invention can be achieved and all the functions of the recording unit 12 and the monitoring unit 20 can be achieved, the recording unit 12 and the monitoring unit 20 can be integrated into one component. In one embodiment, the recording unit 12 and the monitoring unit 20 can be integrated into one computing device.

[0052] Continue to refer to Figure 2 , the non-contact plasma monitoring device can monitor the plasma in an inductively coupled plasma generator. In one embodiment, the non-contact plasma monitoring device can monitor the plasma in an inductively coupled plasma generator having an antenna formed on at least one plane. In one embodiment, the non-contact plasma monitoring device can monitor the plasma in an inductively coupled plasma generator having an antenna formed on an upper plane. In one embodiment, the non-contact plasma monitoring device can monitor the plasma in an inductively coupled plasma generator having a helical antenna formed on an upper plane. Figure 2 In the figure, the shape of the antenna is shown as a spiral shape, but this is only an example and the shape of the antenna is not particularly limited. Although the inductively coupled plasma generator and / or the antenna of the inductively coupled plasma generator are not structures included or integrated in the non-contact plasma monitoring device according to an embodiment of the present invention, the position and direction of the non-contact plasma monitoring device according to an embodiment of the present invention and / or the RF sensor 11 included in the device can be determined to be optimized for measuring the plasma state of a general inductively coupled plasma generator and / or a specific inductively coupled plasma generator. In one embodiment, each of the RF sensors can be formed to be configured outside the antenna. In one embodiment, each of the RF sensors can be formed so that the plane formed by each of the RF sensors is perpendicular to the plane formed with the antenna. In one embodiment, each of the RF sensors 11 can be formed so that the plane formed by each of the RF sensors is perpendicular to the plane formed with the spiral antenna. By configuring the RF sensor as described above, the RF sensor in the device can generate an induced electromotive force from the antenna.

[0053] The information of the separated frequency output after the Fourier transform of the operation unit 21 or the plasma state derived by the output unit 22 is not particularly limited as long as the correlation can be derived. In one embodiment, the n is 1, that is, the information about the component frequency derived by the operation unit 21 is the amplitude value of the first harmonic, and the output unit 22 derives a linear proportional relationship between the plasma electron density directly measured inside the plasma generator and each amplitude value, and the unknown plasma electron density can be derived from the amplitude value measurement result through the linear proportional relationship. In one embodiment, the non-contact plasma monitoring device according to an embodiment of the present invention can be pre-calibrated by a value derived from a measurement device (including a probe method) inserted into a conventional plasma.

[0054] Continue to refer to Figure 2 In one embodiment, the sensor unit 10 may include more than two RF sensors 11 . Figure 3 FIG. 1 is a diagram showing an embodiment of a method for arranging a plurality of RF sensors when the non-contact plasma monitoring device according to an embodiment of the present invention includes two or more RF sensors. Figure 3 and Figure 2 In one embodiment, two or more of the RF sensors 11 may be configured such that radial distances in the spiral formed by the antennas are different from each other. In this case, in one embodiment, the output unit may derive the distribution of unknown plasma electron density by deriving each plasma electron density from each RF sensor.

[0055] Continue to refer to Figure 3 In one embodiment, one or more of the RF sensors may be configured to be located on the antenna.

[0056] Continue to refer to Figure 2 As another embodiment, the operation unit 21 can derive the amplitude values ​​of multiple harmonics, thereby the output unit 22 can derive other plasma related information except the plasma electron density or the distribution of the plasma electron density. In one embodiment, the output unit 22 can confirm whether impurities are introduced into the plasma by whether the change in the amplitude value of the nth harmonic exceeds a preset level. In one embodiment, n can be 5 or 6.

[0057] As described above, according to the non-contact plasma monitoring apparatus of the embodiment of the present invention, the plasma state can be monitored by implementing the non-contact plasma monitoring method while maintaining the stability of the plasma.

[0058] The following are examples of the present invention. However, the following examples are only examples of the present invention, and the scope of the present invention is not limited to the following examples.

[0059] Fabrication of a non-contact plasma monitoring device

[0060] The RF sensor is configured so that the RF sensor can be configured on the antenna of a specific inductively coupled plasma generator. The inductively coupled plasma generator includes a spiral antenna, and the RF sensor is respectively located at points 40, 88, 120, 152, 180, and 200 mm from the center of the spiral in the radial direction, and is configured so that the plane formed by the RF sensor is perpendicular to the plane formed with the spiral antenna. The induced electromotive force sensed to each RF sensor is measured according to time, and after Fourier transformation of the induced electromotive force as a function of time, it is connected to a computing device equipped with software capable of deriving the amplitude value of the nth harmonic. Thus, a non-contact plasma monitoring device according to an embodiment of the present invention is manufactured.

[0061] Calibration and measurement of non-contact plasma monitoring devices

[0062] The inductively coupled plasma generator was filled with nitrogen and operated at an operating pressure of 10, 20, or 30 mTorr. The power applied to the antenna was 400, 600, or 800 W. A probe capable of measuring the electron density of the plasma was pre-inserted into the inductively coupled plasma generator, and the correlation with the amplitude value of the nth harmonic derived from the non-contact plasma monitoring device was analyzed.

[0063] Figure 4 is a graph showing a function of recording the induced electromotive force over time. Figure 4 The left side shows the experimental results when the operating pressure is fixed at 20mTorr, and the right side shows the experimental results when the applied power is fixed at 600W.

[0064] When driven as described above, the probe simultaneously measures the electron density. Figure 5 The following is a graph showing the results.

[0065] According to the operating conditions of the plasma generator, the amplitude value of the first harmonic is compared with the electron density measured with the probe. Figure 6 6, it can be confirmed that the amplitude value of the first harmonic derived from the plasma monitoring device and the electron density directly measured by the probe have similar trends.

[0066] Figure 7 The results of comparing the values ​​directly measured by the probe with the values ​​derived from the amplitude value of the first harmonic were used to quantitatively confirm the above-mentioned similar trends. Figure 7 , the linear trend analysis of the two value point graphs confirmed that the R2 value was 0.95835, showing a very high linear correlation. It can be confirmed that the electron density and its distribution in the inductively coupled plasma device can be obtained from the amplitude of the first harmonic without the need for direct measurement by the probe.

[0067] Figure 8 is a graph showing the change in the amplitude value of each nth harmonic when the probe operates in the inductively coupled plasma generator. Center indicates that the probe is located at the center of the plasma generator, and edge and edge2 indicate that the probe is located at the end of the generator. Figure 8 Although the amplitude of the first harmonic does not change greatly depending on the position of the probe, the amplitude of the fifth harmonic and the amplitude of the sixth harmonic clearly show a tendency to increase first and then decrease, or decrease first and then increase. It can be confirmed that when the amplitude of the fifth and sixth harmonics changes significantly beyond the preset value, it can be used as a sensing signal that impurities have entered the plasma.

[0068] Simulation of spatial magnetic field distribution

[0069] Fig. 9 It is the result of simulating the spatial magnetic field distribution while controlling the current applied to the antenna on the plasma generator. Fig. 9 , it can be confirmed that the magnetic field distribution around the antenna changes with the change of the antenna operating conditions. Therefore, based on this, if an RF sensor is configured around the antenna, the induced electromotive force value measured by the RF sensor can be compared with the magnetic field value obtained by simulation, and finally plasma variables such as electron density or temperature can be derived. This confirms that the state and uniformity of the plasma can be monitored from outside the plasma generator by the RF sensor.

[0070] Although the present invention has been described above with reference to preferred embodiments thereof, it will be appreciated by those skilled in the art that various modifications and variations may be made to the present invention without departing from the spirit and scope of the invention as described in the appended claims.

Claims

1. A non-contact plasma monitoring method, wherein: include: In the first step, one or more RF sensors are arranged outside the inductively coupled plasma generator including an antenna, and the induced electromotive force induced to the RF sensor is measured through the antenna as a function of time; The second step is to perform Fourier transformation on the function of the induced electromotive force at each time, and derive the amplitude value of the nth harmonic respectively; as well as The third step is to derive the state of the plasma in the plasma generator from the amplitude value of each nth harmonic. The n is a natural number greater than or equal to 1.

2. The non-contact plasma monitoring method according to claim 1, wherein: The antenna is formed on at least one plane of the inductively coupled plasma generator, Each of the RF sensors is disposed outside of the antenna.

3. The non-contact plasma monitoring method according to claim 1, wherein: The n is 1, In the third step, after deriving a linear proportional relationship between the plasma electron density directly measured inside the plasma generator and the amplitude values, an unknown plasma electron density is derived from the amplitude value measurement result using the linear proportional relationship.

4. The non-contact plasma monitoring method according to claim 3, wherein: In the first step, two or more RF sensors are configured, In the third step, the distribution of the unknown plasma electron density is derived by deriving the plasma electron density from each of the RF sensors.

5. The non-contact plasma monitoring method according to claim 2, wherein: In the third step, whether impurities are introduced into the plasma is confirmed by whether the change in the amplitude value of the nth harmonic exceeds a preset level.

6. The non-contact plasma monitoring method according to claim 5, wherein: The n is 5 or 6.

7. A non-contact plasma monitoring device, wherein: include: A sensor unit, comprising: one or more RF sensors; and a recording unit capable of measuring an induced electromotive force sensed to each of the RF sensors and recording a function over time; as well as The monitoring unit comprises: a computing unit capable of performing Fourier transform on the function of each induced electromotive force according to the recorded time; and an output unit capable of deriving the state of the plasma from the amplitude value of the nth harmonic from each Fourier transform result of the computing unit, The n is a natural number greater than or equal to 1.

8. The non-contact plasma monitoring device according to claim 7, wherein: The non-contact plasma monitoring device is capable of monitoring plasma in an inductively coupled plasma generator having an antenna formed on at least one plane. Each of the RF sensors is formed to be disposed outside the antenna.

9. The non-contact plasma monitoring device according to claim 7, wherein: The n is 1, The output unit derives a linear proportional relationship between the plasma electron density directly measured inside the plasma generator and each of the amplitude values, and then derives the unknown plasma electron density from the amplitude value measurement result through the linear proportional relationship.

10. The non-contact plasma monitoring device according to claim 9, wherein: The sensor unit includes more than two RF sensors, The output unit derives the distribution of unknown plasma electron density by deriving the plasma electron density from each of the RF sensors.

11. The non-contact plasma monitoring device according to claim 8, wherein: The output unit confirms whether impurities are introduced into the plasma by determining whether a change in the amplitude value of the nth harmonic exceeds a preset level.

12. The non-contact plasma monitoring device according to claim 11, wherein: The n is 5 or 6.

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