Non-contact plasma monitoring method and non-contact plasma monitoring device using the same

Abstract

A non-contact plasma monitoring method and a non-contact plasma monitoring device using the same are disclosed. The non-contact plasma monitoring method may include: a first step of arranging one or more RF sensors outside an inductively coupled plasma generator including an antenna, and measuring, as functions of time, the induced electromotive forces induced in the RF sensors by the antenna; a second step of Fourier-transforming the functions of the induced electromotive forces with respect to each time, and then deriving the amplitude values of the nth harmonics; and a third step of deriving the state of the plasma in the plasma generator from the amplitude values of the respective nth harmonics.

Description

Technical Field

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

Background Art

[0002] When operating a plasma generator, a method of directly installing a diagnostic device in a plasma reactor is used to measure the plasma state such as the electron density and electron temperature of the plasma. In this case, contamination of the diagnostic device may occur depending on the process conditions. In addition, when a diagnostic device is applied during the progress of the process, the stability of the process may be reduced and impurities may flow in. Therefore, a method for measuring the plasma state outside the plasma generator is required.

Summary of the Invention

Problems to be Solved by the Invention

[0003] One object of the present invention is to provide a non-contact plasma monitoring method capable of measuring the plasma state outside without installing a diagnostic device inside the plasma reactor.

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

Means for Solving the Problems

[0005] On one side, the present invention provides a non-contact plasma monitoring method, which includes: a first step of arranging one or more RF sensors outside an inductively coupled plasma (ICP) generator including an antenna, and respectively measuring the induced electromotive force induced in the RF sensor by the antenna as a function of time; a second step of performing a Fourier transform on the function of the induced electromotive force for each time, and then respectively deriving the amplitude values of the nth harmonics; and a third step of deriving the state of the plasma in the plasma generator from the amplitude values of the respective nth harmonics. Here, n may be a natural number of 1 or more.

[0006] Through the steps as described above, the non-contact plasma monitoring method of the present invention can monitor the plasma state outside the plasma generator.

[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 RF sensor may be arranged outside the antenna. In one embodiment, each RF sensor may be arranged such that the plane formed by each RF sensor is perpendicular to the plane on which the antenna is formed. In one embodiment, each RF sensor may be arranged such that the plane formed by each RF sensor is perpendicular to the plane on which the spiral antenna is formed.

[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, n is 1, and in the third step, 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 according to the linear proportional relationship.

[0010] In one embodiment, in the first step, two or more RF sensors may be arranged. 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, two or more of the RF sensors may be arranged such that the radial distances are different in the spiral formed by the antenna. In one embodiment, in the third step, by deriving the plasma electron density from each RF sensor, the distribution of the unknown plasma electron density can be derived.

[0011] In one embodiment, each RF sensor may be arranged to be located on the antenna.

[0012] In one embodiment, in the third step, it is possible to confirm whether impurities have flowed into the plasma according to whether the amplitude value of the nth harmonic has changed to a level equal to or higher than a predetermined level. In one embodiment, n may be 5 or 6.

[0013] In another aspect, the present invention provides a non-contact plasma monitoring device including: a sensor unit including one or more RF sensors and a recording unit capable of measuring the induced electromotive force induced in each RF sensor and recording this as a function of time; and a monitor unit including an arithmetic unit capable of performing a Fourier transform on the function of each induced electromotive force with respect to the recorded time, and an output unit for deriving the state of the plasma through the amplitude value of the nth harmonic from each Fourier transform result of the arithmetic unit. Here, n may be a natural number of 1 or more.

[0014] The above-described apparatus 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 apparatus can monitor the plasma in an inductively coupled plasma generator in which an antenna is formed on at least one plane. In one embodiment, the non-contact plasma monitoring apparatus can monitor the plasma in an inductively coupled plasma generator in which an antenna is formed on an upper plane. In one embodiment, the non-contact plasma monitoring apparatus can monitor the plasma in an inductively coupled plasma generator in which a spiral antenna is formed on an upper plane. In one embodiment, each of the RF sensors may be formed to be disposed outside the antenna. In one embodiment, each of the RF sensors may be formed such that the plane formed by each of the RF sensors is perpendicular to the plane in which the antenna is formed. In one embodiment, each of the RF sensors may be formed such that the plane formed by each of the RF sensors is perpendicular to the plane in which the spiral antenna is formed.

[0016] By arranging the RF sensors as described above, an induced electromotive force can be generated in the RF sensors of the apparatus 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 of the amplitude values, the output unit can derive the unknown plasma electron density from the amplitude value measurement result according to the linear proportional relationship.

[0018] In one embodiment, the sensor unit may include two or more 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, two or more of the RF sensors may be arranged such that the radial distances are different in the spiral formed by the antenna. In one embodiment, the output unit can derive the distribution of the plasma electron density, which is not detailed, by deriving the plasma electron density from each of the RF sensors.

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

[0020] In one embodiment, the output unit can confirm whether impurities have flowed into the plasma based on whether the amplitude value of the nth harmonic has changed to a level equal to or higher than a predetermined level. In one embodiment, the n may be 5 or 6.

Advantages of the Invention

[0021] The non-contact plasma monitoring device according to an embodiment of the present invention can monitor the plasma state including the plasma electron density and the presence or absence of impurities outside the plasma, so that the stability of the plasma can be ensured.

[0022] The non-contact plasma monitoring device according to an embodiment of the present invention can embody the non-contact plasma monitoring method and monitor the plasma state while maintaining the stability of the plasma.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention can be subjected to various modifications and can have various forms. Specific examples are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and it should be understood to include all modifications, equivalents, or alternatives included in the spirit and technical scope of the present invention. When explaining each drawing, similar reference numerals are used for similar components. In the attached drawings, the dimensions of the structure are shown enlarged compared to the actual ones for the sake of clarity of the present invention.

[0025] The terms used in this application are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "including" or "having" are intended to specify the existence of features, numbers, steps, operations, components, or combinations thereof described in the specification, and it should be understood that they do not preclude the existence or addition possibility of one or more other features, numbers, steps, operations, components, or combinations thereof.

[0026] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or overly formal sense unless clearly defined in this application.

[0027] Figure 1 is a flowchart showing a non-contact plasma monitoring method according to an embodiment of the present invention.

[0028] Referring to FIG. 1, a non-contact plasma monitoring method according to an embodiment of the present invention includes: a first step (S110) of arranging one or more RF sensors outside an inductively coupled plasma (ICP) generator including an antenna, and measuring the induced electromotive force induced in the RF sensor by the antenna as a function of time; a second step (S120) of performing a Fourier transform on the function of the induced electromotive force with respect to each time, and then deriving the amplitude values of the nth harmonics; and a third step (S130) of deriving the state of the plasma in the plasma generator from the amplitude values of the respective nth harmonics. Here, n may be a natural number of 1 or more. By the steps as described above, the non-contact plasma monitoring method of the present invention can monitor the plasma state outside the plasma generator.

[0029] The first step (S110) measures the induced electromotive force generated from the plasma generator, particularly as a function of time. The plasma generator, particularly an inductively coupled plasma generator, can include an antenna, and a plasma can be generated inside the plasma generator by the current applied to the antenna and the change in the current, and a change in the peripheral magnetic field can occur from the antenna. Therefore, when an RF sensor is disposed around the antenna, an induced electromotive force can be induced in the RF sensor from the change in the magnetic field. Therefore, the RF sensor can be disposed at a position and in an orientation where an induced electromotive force can 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 disposed outside the antenna. In one embodiment, each RF sensor may be disposed such that a plane formed by each RF sensor is perpendicular to a plane in which the antenna is formed. In one embodiment, each RF sensor may be disposed such that a plane formed by each RF sensor is perpendicular to a plane in which the spiral antenna is formed. As described above, by disposing the RF sensor, an induced electromotive force can be induced from the antenna to the RF sensor.

[0030] The second step (S120) is a process of performing Fourier transform on the function of the induced electromotive force with respect to time. As is known in the art, Fourier transform can decompose a function with respect to time into frequency components, and the primary frequency components can be numbered in the order of the first harmonic, the second harmonic, etc. That is, in the context of this specification, a harmonic is, as a result of Fourier transform, the nth harmonic means the harmonic wave where the frequency components appearing in the Fourier transform result are sequentially the main ones, and the nth component, and the amplitude value of the nth harmonic means the amplitude value of the harmonic wave. The second step (S120) performs Fourier transform on the function of the induced electromotive force with respect to time to separate each frequency component and derive the amplitude value of each frequency component or a specific nth harmonic.

[0031] The third step (S130) is a step capable of extracting information regarding the plasma state 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 how close it is to the main frequency component of the function of the induced electromotive force with respect to time is determined by the value of n. Therefore, from the combination of the second step (S120) and the third step (S130), the non-contact plasma monitoring method according to an embodiment of the present invention can derive a specific plasma state.

[0032] In one embodiment, 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 according to the linear proportional relationship. The method of directly measuring inside the plasma generator may be measurement by a probe. The method of directly measuring the plasma electron density inside the plasma generator as described above is an existing technique as described above, and has the disadvantage of affecting the plasma electron density. The non-contact plasma monitoring method according to an embodiment of the present invention is based on the discovery that the plasma electron density measured by the prior art as described above and the amplitude value of the first harmonic of the Fourier transform result of the function of the induced electromotive force over 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 according to an embodiment of the present invention can be calibrated by the conventional direct measurement method.

[0033] The method as described above is related to the relative positional relationship between the RF sensor and the antenna and the electron density at the point to be measured. Therefore, when two or more 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, two or more of the RF sensors may be arranged in the first step (S110). In one embodiment, two or more of the RF sensors may be arranged such that the radial distances are different in the spiral formed by the antenna. In one embodiment, in the third step (S130), the distribution of the unknown plasma electron density can be derived by deriving the plasma electron density from each RF sensor.

[0034] The RF sensor is not particularly limited as long as it is arranged around the antenna, particularly above the antenna, at a position where an induced electromotive force can be induced. In one embodiment, each RF sensor may be arranged to be located on the antenna.

[0035] As described above, measuring the electron density of the plasma or the electron density distribution of the plasma is only one embodiment of the plasma state that can be derived by the non-contact plasma monitoring method according to the embodiments of the present invention. When the correlation with other plasma states measured by the prior art can be derived using the method as described above, the type of the plasma state is not particularly limited.

[0036] In one embodiment, in the third step (S130), it is possible to confirm whether impurities have flowed into the plasma depending on whether the amplitude value of the nth harmonic has changed to a level equal to or higher than a predetermined level. In one embodiment, the n may be 5 or 6.

[0037] As described above, the non-contact plasma monitoring device according to the embodiments of the present invention can monitor the plasma state including the plasma electron density and the presence or absence of impurities outside the plasma, so that the stability of the plasma can be ensured.

[0038] FIG. 2 shows the configuration of the non-contact plasma monitoring device according to the embodiments of the present invention.

[0039] Referring to FIG. 2, the non-contact plasma monitoring device according to the embodiments of the present invention includes a sensor unit 10 including one or more RF sensors 11 and a recording unit 12 that measures the induced electromotive force induced in each of the RF sensors 11 and can record this as a function of time; and an arithmetic unit 21 that can perform a Fourier transform on the function of each induced electromotive force with respect to the recorded time, and an output unit 22 that derives the state of the plasma from the amplitude value of the nth harmonic from each Fourier transform result of the arithmetic unit 21. A non-contact plasma monitoring device 1 is provided. Here, the n may be a natural number of 1 or more. Such a device can ensure the stability of the plasma by monitoring the state of the plasma outside the plasma generator.

[0040] The non-contact plasma monitoring device according to an embodiment of the present invention is an example of a device that can embody the aforementioned non-contact plasma monitoring method. Regarding descriptions of terms that are the same as or similar to those used in the detailed description of the aforementioned non-contact plasma monitoring method, they can be applied to the same or similar members of the non-contact plasma monitoring device according to the embodiment of the present invention in the same or similar manner.

[0041] The RF sensor 11 is a member in which an induced electromotive force can be induced from a plasma generator or a part of the plasma generator. In the context of this specification, an RF sensor is a device that can sense a signal having a radio frequency (RF), and may include a coil as an example. In the context of this specification, a coil is an electric wire member that forms one or more closed surfaces with the conductor closed. When a change occurs in the magnetic field passing through the closed surface formed by the conductor, an electromotive force is induced so that an electric current can flow through the conductor, meaning an electric wire member.

[0042] One or more of the RF sensors 11 may be provided. In one embodiment, one RF sensor 11 may be provided. In other embodiments, more than one RF sensor 11 may be provided.

[0043] The recording unit 12 is a device that can measure and record the induced electromotive force induced in the RF sensor 11. The induced electromotive force can be recorded as a function of time, where the recording unit 12 may further include a separate storage device. In one embodiment, the recording unit 12 can directly measure the induced electromotive force. In other embodiments, the recording unit 12 can measure a physical quantity such as a current that is not the induced electromotive force, and then calculate the electromotive force to measure the induced electromotive force. In this case, the recording unit 12 may further include a separate calculation device.

[0044] The arithmetic unit 21 can perform a Fourier transform on the function of the induced electromotive force measured and recorded by the recording unit 12 with respect to time to identify the component frequencies and derive the amplitude values of each frequency. In one embodiment, the arithmetic unit 21 can derive the amplitude values of the nth harmonic from the Fourier transform result.

[0045] The output unit 22 can derive the plasma state from the information regarding the component frequencies derived by the arithmetic unit 21, particularly the amplitude values of the nth harmonic. In one embodiment, the method by which the output unit 22 derives the plasma state is related to the correlation between the specific plasma state measured by the conventional technique and the information regarding the component frequencies derived by the arithmetic unit 21, particularly the amplitude values of the nth harmonic, and can be derived by calibration, particularly by a linear correlation.

[0046] Subsequently, referring to FIG. 2, the arithmetic unit 21 and the output unit 22 are shown as separate members, but this is exemplary and for the purpose of explaining the functional aspects. If the object of the present invention can be achieved and all the functions of the arithmetic unit 21 and the output unit 22 can be executed, the arithmetic unit 21 and the output unit 22 may be integrated into one member. In one embodiment, the arithmetic unit 21 and the output unit 22 may be integrated into one computing device.

[0047] Referring to FIG. 2, the recording unit 12 and the monitor unit 20 are shown as separate members, but this is exemplary and for the purpose of explaining the functional aspects. If the object of the present invention can be achieved and all the functions of the recording unit 12 and the monitor unit 20 can be executed, the recording unit 12 and the monitor unit 20 may be integrated into one member. In one embodiment, the recording unit 12 and the monitor unit 20 may be integrated into one computing device.

[0048] Next, referring to FIG. 2, the non-contact plasma monitoring device can monitor the plasma in the inductively coupled plasma generator. In one embodiment, the non-contact plasma monitoring device can monitor the plasma in an inductively coupled plasma generator in which an antenna is 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 in which an antenna is formed on an upper plane. In one embodiment, the non-contact plasma monitoring device can monitor the plasma in an inductively coupled plasma generator in which a spiral antenna is formed on an upper plane. Although the form of the antenna is shown spirally in FIG. 2, this is exemplary and the form of the antenna is not particularly limited. The inductively coupled plasma generator and / or the antenna of the inductively coupled plasma generator are not included or integrated in the non-contact plasma monitoring device according to the embodiment of the present invention, but the non-contact plasma monitoring device according to the embodiment of the present invention and / or the RF sensor 11 included in the device are optimized for measuring the plasma state of a general inductively coupled plasma generator and / or a specific inductively coupled plasma generator, and the position and orientation can be determined. In one embodiment, each RF sensor can be formed to be disposed outside the antenna. In one embodiment, each RF sensor may be formed such that the plane formed by each RF sensor is perpendicular to the plane in which the antenna is formed. In one embodiment, each RF sensor 11 may be formed such that the plane formed by each RF sensor is perpendicular to the plane in which the spiral antenna is formed. As described above, by arranging the RF sensors, an induced electromotive force can be generated in the RF sensors of the device from the antenna.

[0049] The information on the component frequencies output by the arithmetic unit 21 after Fourier transform and the plasma state derived by the output unit 22 are not particularly limited as long as the correlation relationship can be derived. In one embodiment, n is 1. That is, the information on the component frequencies derived by the arithmetic unit 21 is the amplitude value of the fundamental harmonic, and after the output unit 22 derives 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 according to the linear proportional relationship. In one embodiment, the non-contact plasma monitoring device according to the embodiment of the present invention can be calibrated in advance by the value derived by a measuring device inserted into a conventional plasma including a probe method.

[0050] Subsequently, referring to FIG. 2, in one embodiment, the sensor unit 10 may include two or more RF sensors 11. FIG. 3 is a drawing showing an embodiment of the arrangement method of a plurality of RF sensors when the non-contact plasma monitoring device according to the embodiment of the present invention includes two or more RF sensors. Referring to FIG. 3 together with FIG. 2, in one embodiment, two or more of the RF sensors 11 may be arranged such that the radial distances are different in the spiral formed by the antenna. Also, in this case, in one embodiment, the output unit can derive the distribution of the unknown plasma electron density by deriving the plasma electron density from each RF sensor.

[0051] Subsequently, referring to FIG. 3, in one embodiment, one or more of the RF sensors may be arranged to be located on the antenna.

[0052] Next, referring to FIG. 2, as another embodiment, the arithmetic unit 21 can derive the amplitude values of a plurality of harmonics, and from this, the output unit 22 can derive plasma-related information other than the plasma electron density and the distribution of the plasma electron density. In one embodiment, the output unit 22 can confirm whether impurities have flowed into the plasma depending on whether the amplitude value of the nth harmonic has changed to a level equal to or higher than a predetermined level. In one embodiment, n may be 5 or 6.

[0053] As described above, the non-contact plasma monitoring device according to the embodiment of the present invention implements the non-contact plasma monitoring method and can monitor the plasma state while maintaining the stability of the plasma.

[0054] Hereinafter, embodiments of the present invention will be described. However, the embodiments described below are merely some embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments.

[0055] Manufacture of Non-Contact Plasma Monitoring Device

[0056] An RF sensor is arranged so that it can be arranged on the antenna of a specific inductively coupled plasma generator. The inductively coupled plasma generator includes a spiral antenna, and the RF sensors are arranged in the radial direction at points 40, 88, 120, 152, 180, and 200 mm respectively from the center of the spiral, and the plane formed by the RF sensors is arranged perpendicular to the plane formed by the spiral. The induced electromotive force induced in each RF sensor is measured over time, and after performing a Fourier transform on the function of the induced electromotive force over time, it is connected to a computing device equipped with software capable of deriving the amplitude value of the nth harmonic. In this way, the non-contact plasma monitoring device according to the embodiment of the present invention is manufactured.

[0057] Calibration and Measurement of Non-Contact Plasma Monitoring Device

[0058] The inside of the inductively coupled plasma generator was filled with nitrogen gas and operated at operating pressures of 10, 20, and 30 mTorr. The power applied to the antenna was set to 400, 600, and 800 W. A probe that can measure the electron density of the plasma was previously inserted into the inside of the inductively coupled plasma generator, and the amplitude value of the nth harmonic derived by the non-contact plasma monitoring device was analyzed for correlation.

[0059] Figure 4 is a graph showing a function that records the induced electromotive force over time. The left side of Figure 4 shows the experimental results with the operating pressure fixed at 20 mTorr, and the right side shows the experimental results with the applied power fixed at 600 W.

[0060] When driving as described above, the probe simultaneously measured the electron density. Figure 5 is a graph showing the results.

[0061] The amplitude value of the fundamental harmonic was compared with the electron density measured by the probe according to the operating conditions of the plasma generator. Figure 6 is a graph showing the results. Referring to Figure 6, it can be confirmed that the electron density directly measured by the probe and the amplitude value of the fundamental harmonic derived by the plasma monitoring device have a similar tendency.

[0062] Figure 7 shows the result of comparing the directly measured value by the probe with the derived value by the amplitude value of the fundamental harmonic in order to quantitatively confirm the similar tendency. Referring to Figure 7, as a result of the dot graph of the two values trending linearly, the R 2 value is 0.95835, and it can be confirmed that it shows a very high linear correlation. From this, it can be confirmed that the electron density and its distribution inside the inductively coupled plasma device can be derived from the amplitude value of the fundamental harmonic without directly measuring with the probe.

[0063] FIG. 8 is a graph showing changes in the amplitude values of each nth harmonic when the probe behaves in the inductively coupled plasma generator. Center means that the probe is located at the center of the plasma generator, and edge and edge2 mean that they are located at the ends of the generator. Referring to FIG. 8, while the amplitude value of the fundamental harmonic does not change significantly depending on the position of the probe, the amplitude values of the fifth harmonic and the sixth harmonic clearly show a tendency to increase and then decrease, or decrease and then increase. From this, it can be confirmed that when the amplitude values of the fifth and sixth harmonics vary significantly above a predetermined value, they can be used as a detection signal indicating that impurities have flowed into the plasma.

[0064] Spatial magnetic field distribution simulation

[0065] FIG. 9 shows the result of simulating the distribution of the magnetic field in space by controlling the current applied to the antenna on the plasma generator. Referring to FIG. 9, it can be confirmed that the distribution of the magnetic field changes around the antenna due to changes in the antenna operating conditions. Therefore, based on this, when an RF sensor is located around the antenna, the induced electromotive force value measured by the RF sensor can be compared with the magnetic field value obtained through simulation, and finally plasma variables such as electron density and temperature can be derived. Thus, it can be confirmed that the plasma state and uniformity can be monitored outside the plasma generator through the RF sensor.

[0066] As described above, the preferred embodiments of the present invention have been described with reference thereto. However, those skilled in the art should understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the following claims.

Claims

1. placing one or more RF sensors outside an Inductively Coupled Plasma (ICP) generator including an antenna, and respectively measuring the induced electromotive force induced in the RF sensor by the antenna as a function of time; a second step of respectively deriving the amplitude values of the nth harmonics after performing a Fourier transform on the function of the induced electromotive force for each of the times; and a third step of deriving the state of the plasma in the plasma generator from the amplitude value of each of the nth harmonics; comprising; a non-contact plasma monitoring method, wherein the n is a natural number of 1 or more.

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

3. the n is 1; in the third step, after deriving the linear proportional relationship between the plasma electron density directly measured inside the plasma generator and each of the amplitude values, the unknown plasma electron density is derived from the amplitude value measurement result through the linear proportional relationship. The non-contact plasma monitoring method according to claim 1.

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

5. in the third step, it is confirmed whether impurities have flowed into the plasma according to whether the amplitude value of the nth harmonic has changed to a level equal to or higher than a predetermined level. The non-contact plasma monitoring method according to claim 2.

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

7. a sensor unit including one or more RF sensors and a recording unit capable of measuring the induced electromotive force induced in each of the RF sensors and recording this as a function of time; and a monitor unit including an arithmetic unit capable of performing a Fourier transform on the function of each induced electromotive force according to the recorded time, and an output unit for deriving the state of the plasma from the amplitude value of the nth harmonic from each Fourier transform result of the arithmetic unit; comprising; The non-contact plasma monitoring device, wherein n is a natural number of 1 or more.

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

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

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

11. The output unit checks whether impurities have flowed into the plasma according to whether the amplitude value of the nth harmonic has changed to a level equal to or higher than a predetermined level. The non-contact plasma monitoring device according to claim 8.

12. n is 5 or 6, and the non-contact plasma monitoring device according to claim 11.

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