Integrated modular spectroscopic system and process diagnosis method using same

Abstract

In an integrated modular spectroscopic system and a process diagnosis method using same, the spectroscopic system comprises a spectroscopic module, a detection unit and a diagnosis unit. The spectral module receives an optical signal emitted from a plasma process. The detection unit detects an optical signal according to a frequency band on the basis of the optical signal received at the spectroscopic module. The diagnosis unit determines the state of the plasma process or the calibration time of the spectroscopic module on the basis of the detected optical signal. Here, the spectroscopic module comprises: a first spectrometer for receiving an optical signal of a first wavelength band through diffraction spectroscopy; and a second spectrometer for receiving an optical signal of a second wavelength band through transmission spectroscopy.

Description

Integrated modular spectroscopy system and process diagnostic method using the same

[0001] The present invention relates to an integrated modular spectroscopic system and a process diagnostic method using the same, and more particularly, to an integrated modular spectroscopic system that uses an integrated modular spectroscopic system that integrates a diffraction-based spectrometer and a transmission-based spectrometer to diagnose the progress status of various processes in a process utilizing plasma, whether there is an abnormality in the process, when to replace the spectrometer, or whether there is contamination in a viewing window, and a process diagnostic method using the same.

[0002] Typically, in semiconductor or display manufacturing processes utilizing plasma, information about changes in the properties of atoms, molecules, ions, or electrons can be obtained based on the optical signals emitted during the process. Furthermore, this information can be used to determine the end state of the manufacturing process.

[0003] The optical signal emitted in this manufacturing process is mainly detected using a spectrometer, and the spectrometer typically used is a Czerny-Turner type spectrometer as described in Korean Patent Publication No. 10-2023-0058376.

[0004] That is, through the Czerny-Turner type spectrometer, the light signal emitted during the process is input into the diffraction spectrometer through an optical fiber, diffracted through a grating, and then the intensity according to each wavelength formed on the CCD array can be measured.

[0005] However, in the case of these diffraction-type spectrometers, the same wavelength resolution is provided across the entire observation wavelength range, and there are limits to improving sensitivity. Furthermore, there are limitations in that wavelength resolution and sensitivity, etc., may fluctuate depending on the arrangement of individual elements constituting the spectrometer. In particular, there are problems in that misalignment of the optical path may occur due to vibration or temperature changes in the manufacturing facility, or errors may occur due to changes in optical properties.

[0006] Accordingly, the technical problem of the present invention is conceived from this point, and the purpose of the present invention is to provide an integrated modular spectroscopic system that can effectively diagnose the progress status of various processes in a process utilizing plasma, whether there is an abnormality in the process, when to replace the spectrometer, or whether there is contamination of the viewing window, by using an integrated modular spectrometer that integrates a diffraction-based spectrometer and a transmission-based spectrometer.

[0007] In addition, another object of the present invention is to provide a process diagnosis method using the above-described spectroscopic system.

[0008] According to one embodiment of the present invention, a spectroscopic system includes a spectroscopic module, a detection unit, and a diagnostic unit. The spectroscopic module receives an optical signal emitted from a plasma process. The detection unit detects an optical signal according to a frequency band based on the optical signal received from the spectroscopic module. The diagnostic unit determines the state of the plasma process or the timing of correction of the spectroscopic module based on the detected optical signal. In this case, the spectroscopic module includes a first spectrometer that receives an optical signal in a first wavelength band by performing diffraction spectroscopy, and a second spectrometer that receives an optical signal in a second wavelength band by performing transmission spectroscopy.

[0009] In one embodiment, the optical signal of the first wavelength band may be an optical signal of the ultraviolet (UV), visible light (VIS), and infrared (IR) wavelength bands, and the optical signal of the second wavelength band may be an optical signal of the ultraviolet (UV) and visible light (VIS) wavelength bands.

[0010] In one embodiment, the detection unit may include a first optical signal detection unit that detects optical signals in ultraviolet, visible, and infrared wavelength bands received from the first spectrometer and optical signals in ultraviolet and visible wavelength bands received from the second spectrometer.

[0011] In one embodiment, the diagnostic unit may include a process determination unit that determines the end point of the plasma process based on an optical signal detected by the first optical signal detection unit.

[0012] In one embodiment, the second spectrometer may further include a filter section that selectively transmits only wavelengths of a specific band belonging to the ultraviolet (UV) and visible light (VIS) wavelength bands.

[0013] In one embodiment, the detection unit may include a second optical signal detection unit that detects whether an optical signal in the ultraviolet and visible light wavelength band received from the first spectrometer is shifted relative to an optical signal in the ultraviolet and visible light wavelength band received from the second spectrometer.

[0014] In one embodiment, the diagnostic unit may include a correction determination unit that determines the alignment correction time of the first spectrometer based on the movement state of the optical signal detected by the second optical signal detection unit.

[0015] In one embodiment, the method may further include a viewing window interposed between the process chamber in which the plasma process is performed and the spectroscopic module, through which an optical signal emitted from the plasma process is transmitted.

[0016] In one embodiment, the detection unit may include a third optical signal detection unit that detects the transmittance of an optical signal in the ultraviolet and visible light wavelength bands received from the first spectrometer and the transmittance of an optical signal in the ultraviolet and visible light wavelength bands received from the second spectrometer.

[0017] In one embodiment, the diagnostic unit may include a replacement determination unit that determines the replacement time of the sight glass based on the transmittance of the optical signal detected by the third optical signal detection unit.

[0018] In one embodiment, the first spectrometer can receive the optical signal through an optical fiber, and the second spectrometer can receive the optical signal through the viewing window.

[0019] In one embodiment, the time to replace the optical fiber or the time to replace the viewing window can be determined by comparing the difference between the transmittance of the optical signal received from the first spectrometer and the transmittance of the optical signal received from the second spectrometer.

[0020] In another embodiment of the process diagnosis method for realizing the above-described object of the present invention, an optical signal emitted from a plasma process is received through a spectroscopic module. Based on the received optical signal, an optical signal according to a frequency band is detected. Based on the detected optical signal, the state of the plasma process or the calibration time of the spectroscopic module is determined. In this case, the spectroscopic module includes a first spectrometer that receives an optical signal in a first wavelength band by performing diffraction spectroscopy, and a second spectrometer that receives an optical signal in a second wavelength band by performing transmission spectroscopy.

[0021] In one embodiment, in the step of determining the state of the plasma process, the end point of the plasma process can be determined based on the optical signal for each wavelength band of the detected optical signal.

[0022] In one embodiment, the detected optical signal may be an optical signal in the ultraviolet, visible, and infrared wavelength bands received from the first spectrometer, and an optical signal in the ultraviolet and visible wavelength bands received from the second spectrometer.

[0023] In one embodiment, in the step of determining the calibration time of the spectroscopic module, the alignment calibration time of the first spectroscopic module can be determined based on the state in which the optical signal received from the first spectroscopic module moves relative to the optical signal received from the second spectroscopic module.

[0024] In one embodiment, the optical signals received from the first spectrometer and the second spectrometer may be optical signals in the ultraviolet and visible light wavelength bands.

[0025] In one embodiment, the optical signal is received by the spectrophotometer module through the sight glass, and the time of replacement of the sight glass can be determined based on the transmittance of the optical signal received by the first spectrophotometer among the spectrophotometer modules and the transmittance of the optical signal received by the second spectrophotometer among the spectrophotometer modules.

[0026] In one embodiment, the transmittance of the optical signals received from the first spectrometer and the second spectrometer may be the transmittance of optical signals in the visible light and ultraviolet wavelength bands.

[0027] According to embodiments of the present invention, by simultaneously using a first spectrometer that performs diffraction spectroscopy and a second spectrometer that performs transmission spectroscopy, an optical signal is detected using the first spectrometer in the visible light (VIS)-infrared (IR) wavelength band, and an optical signal is detected using the second spectrometer in the ultraviolet (UV)-visible light (VIS) wavelength band, thereby enabling detection of optical signals in the entire band with high sensitivity and reliability.

[0028] Thus, by overcoming the resolution limitations of the first spectrometer in a region where adjacent optical signals exist, such as ultraviolet bands or metal atom emission signals, more accurate and reliable optical signal spectral detection is possible.

[0029] In particular, in the case of the second spectrometer, a filter section that can transmit only wavelengths of a specific band is included, so that an optical signal of a specific wavelength band to be monitored can be selectively obtained.

[0030] Accordingly, the end point of the plasma process can be determined more accurately and with high reliability through spectral detection of optical signals in the entire band as described above as well as detection of optical signals in a specific wavelength band.

[0031] In addition, since the first spectrometer tends to shift in wavelength as an alignment error exists, if the wavelength of an optical signal received through the first spectrometer shifts relatively significantly for a specific wavelength band where the first spectrometer and the second spectrometer can be observed together, it is determined that this is the calibration point of the first spectrometer, and calibration of the spectroscopic module can be performed.

[0032] Furthermore, when receiving a plasma emission optical signal through a sight glass, the transmittance of the received optical signal decreases depending on contamination of the sight glass. Since this decrease in transmittance of the optical signal commonly occurs in the first spectrometer and the second spectrometer, it is possible to monitor this and determine the timing of replacement of the sight glass.

[0033] Thus, in monitoring the plasma process status, in addition to simply accurately judging the process end point, information on the alignment status of the spectroscopic module and the contamination status of the viewing window can also be monitored simultaneously, thereby further improving the accuracy and reliability of judging the process end point.

[0034] Figure 1a is a graph illustrating the main emission optical signal during the transition process of argon in each energy region, and Figure 1b is a graph illustrating the main emission optical signal of tungsten.

[0035] FIG. 2 is a block diagram illustrating an integrated modular spectroscopy system according to one embodiment of the present invention.

[0036] Figure 3 is a flowchart illustrating a process diagnosis method using the spectroscopic system of Figure 2.

[0037] Fig. 4 is a graph illustrating an optical signal spectrum that can be monitored using the spectroscopic module of Fig. 2.

[0038] Figures 5a and 5b are graphs illustrating the results of spectroscopically analyzing adjacent wavelength signals using the spectroscopic module of Figure 2.

[0039] Figures 6a and 6b are graphs illustrating a state in which a wavelength signal changes when the flow rate of silane (SiH4) gas changes through spectroscopy using the spectroscopy module of Figure 2.

[0040] FIG. 7a and FIG. 7b are schematic diagrams for explaining the wavelength shift state of an optical signal according to the alignment error of the first spectrometer of FIG. 2.

[0041] Fig. 8a is a graph illustrating the change in transmittance by wavelength according to contamination of the sight glass of Fig. 2, and Fig. 8b is a graph for explaining the timing of sight glass replacement according to the change in sensitivity of the spectral module of Fig. 2.

[0042] <Explanation of symbols>

[0043] 10: Integrated modular spectroscopy system 20: Plasma emission optical signal

[0044] 30: Viewing window 100: Spectrophotometer module

[0045] 110: 1st spectrometer 120: 2nd spectrometer

[0046] 130: Filter section 200: Detection unit

[0047] 210: First optical signal detection unit 220: Second optical signal detection unit

[0048] 230: Third optical signal detection unit 300: Diagnostic unit

[0049] 310: Fair Judgment Department 320: Correction Judgment Department

[0050] 330: Replacement Decision Department

[0051] The present invention is susceptible to various modifications and takes various forms, and thus embodiments are described in detail herein. However, this is not intended to limit the present invention to a specific disclosed form, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Similar reference numerals have been used to designate similar components throughout the description of each drawing. While terms such as "first," "second," etc. may be used to describe various components, these components should not be limited by these terms.

[0052] The above terms are used solely to distinguish one component from another. The terms used in this application are used solely to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0053] In this application, it should be understood that terms such as “comprise” or “consist of” are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0054] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0055] Hereinafter, with reference to the attached drawings, a preferred embodiment of the present invention will be described in more detail.

[0056] First, before explaining the embodiments of the present invention, the frequency band of the light signal emitted according to the type of gas or metal used in a semiconductor or display manufacturing process utilizing plasma is exemplified, and the required wavelength resolution is explained.

[0057] Figure 1a is a graph illustrating the main emission optical signal during the transition process of argon in each energy region, and Figure 1b is a graph illustrating the main emission optical signal of tungsten.

[0058] Through Figure 1a, the main emission optical signal band of argon (Ar), which is widely used as an inert gas in semiconductor and display manufacturing processes, is exemplified.

[0059] That is, in the case of the above argon, in the case of the optical signal emitted in the transition process (2p->1s, s and p are energy sublevels) in a relatively low energy region (e.g., wavelength of 750.4 nm), there is a gap of 10 nm or more between individual optical signals, whereas in the case of the optical signal emitted in the transition process (4p->1s) in a relatively high energy region (e.g., wavelength of 425.9 nm), there is a gap of 1 nm or more between individual optical signals, so it can be confirmed that a relatively very high wavelength resolution is required.

[0060] In addition, through Fig. 1b, the main emission optical signal band of tungsten (W), which is widely used in metal deposition or etching processes among semiconductor or display manufacturing processes, is exemplified.

[0061] That is, even in the case of metals such as the above tungsten, it can be confirmed that the orbital of the outermost electron is a d orbital, and there are many energy levels adjacent to the energy level of the electron that has transitioned.

[0062] Furthermore, in terms of the intensity of the optical signal, collision with high-energy electrons is essential for generating an optical signal having an energy level in a relatively high excited state. However, in the plasma of a typical semiconductor or display manufacturing process, the probability of the existence of high-energy electrons decreases exponentially, so that, in particular, a relatively very high wavelength resolution and high sensitivity are required for measuring the emission optical signal in the ultraviolet (UV) band.

[0063] Accordingly, according to embodiments of the present invention, while selectively detecting an emission light signal particularly in the ultraviolet band, detection is also performed for other light signal bands outside the ultraviolet band, thereby providing a spectroscopic system having high wavelength resolution and high sensitivity for each detection band.

[0064] Hereinafter, embodiments of the present invention will be described in detail.

[0065] FIG. 2 is a block diagram illustrating an integrated modular spectroscopy system according to one embodiment of the present invention.

[0066] Referring to FIG. 2, the integrated modular spectroscopic system (10, hereinafter referred to as the spectroscopic system) according to the present embodiment includes a spectroscopic module (100), a detection unit (200), and a diagnostic unit (300). At this time, the spectroscopic module (100) includes a first spectrometer (110) and a second spectrometer (120), the detection unit (200) includes first to third optical signal detection units (210, 220, 230), and the diagnostic unit (300) includes a process judgment unit (310), a correction judgment unit (320), and a replacement judgment unit (330).

[0067] Here, the first spectrometer (110) is a diffraction spectrometer, and the second spectrometer (120) is a transmission spectrometer.

[0068] As previously described, the above-described spectroscopic system (10) performs spectroscopic analysis on a light signal emitted from a process in which plasma is used, such as a semiconductor or display manufacturing process, that is, a plasma emission light signal (20), thereby performing plasma process-related monitoring. At this time, the detailed exemplary process is not limited to a semiconductor process or a display process, and is not limited to various processes in which plasma is used.

[0069] In addition, in the case of the above-mentioned spectroscopic system (10), the plasma emission light signal (20) is generally received through a viewing window (30) of a process chamber in which the plasma process is performed. The viewing window (30) may be installed in advance on the process chamber, and may be installed in the process chamber in a configuration included in the spectroscopic system (10).

[0070] At this time, in both the case where the viewing window (30) is pre-installed in the process chamber and the case where it is installed together with the installation of the spectroscopic system (10), monitoring of the state of the viewing window (30) can be performed through the spectroscopic system (10) as described below.

[0071] Meanwhile, for convenience of explanation, detailed descriptions of the detailed configurations of the above spectral system (10) are simultaneously explained through the process diagnosis method using the above spectral system (10) described later.

[0072] Figure 3 is a flowchart illustrating a process diagnosis method using the spectroscopic system of Figure 2.

[0073] Referring to FIGS. 2 and 3, in the process diagnosis method using the spectroscopic system (10), first, a plasma emission optical signal (20) is generated through the plasma process (S10), and the plasma emission optical signal (20) generated in this way passes through the viewing window (30) and is provided to the spectroscopic system (10) (step S20).

[0074] Thereafter, referring to FIGS. 2 and 3, the spectral module (100) in the spectral system (10) receives the optical signal (20) provided through the viewing window (30) and monitors it (step S30).

[0075] Specifically, the spectroscopic module (100) includes the first spectrometer (110) and the second spectrometer (120), and the received optical signal (20) is provided to both the first spectrometer (110) and the second spectrometer (120) (steps S31 and S33).

[0076] The above first spectrometer (110) receives the optical signal (20) by diffraction spectroscopy of the optical signal of the first wavelength band.

[0077] The above first spectrometer (110) is a diffraction spectrometer, which receives an optical signal through an optical fiber, diffracts the signal through a grating, and then measures the intensity of each wavelength formed on a CCD array. In this case, the arrangement or structure of the reflective mirror, grating, CCD array, etc. that constitute the first spectrometer (110) can be designed in various ways, and is not limited to a specific structure, and all diffraction spectrometers in the prior art can be applied.

[0078] At this time, the optical signal of the first wavelength band may be an optical signal of the ultraviolet (UV), visible light (VIS), and infrared (IR) wavelength bands.

[0079] That is, through the first spectrometer (110), optical signals of the first wavelength band, that is, optical signals of the ultraviolet (UV), visible light (VIS), and infrared (IR) wavelength bands, are received (step S32). Meanwhile, the infrared wavelength band included in the optical signal of the first wavelength band may be a near infrared (NIR) wavelength band in a narrower range of 750 nm to 1,000 nm.

[0080] In contrast, the second spectrometer (120) receives the optical signal (20) by transmitting and spectroscopy the optical signal of the second wavelength band.

[0081] The second spectrometer (120) is a transmission spectrometer, and is a method of measuring the intensity in the transmitted wavelength band by transmitting only the optical signal of a specific wavelength band with respect to the optical signal. In this case, the second spectrometer (120) may include a filter unit (130) for selectively transmitting only the optical signal of a specific wavelength band. In addition, the filter unit (130) may be selectively mounted to transmit only the specific wavelength band. Meanwhile, the filter unit (130) may include at least one filter, and each filter may selectively transmit only the optical signal of a specific wavelength band, so that the filter unit (130) may selectively transmit the optical signal of the wavelength range required by the filter unit (130) as a whole.

[0082] The optical signal of the second wavelength band may be, for example, an optical signal of the ultraviolet (UV) and visible light (VIS) wavelength bands. However, through the filter unit (130), only an optical signal of a specific wavelength range among the ultraviolet (UV) and visible light (VIS) wavelength bands may be selectively transmitted.

[0083] That is, the second spectrometer (120) may generally be configured with the filter unit (130) to transmit only light signals in the ultraviolet (UV) and visible light (VIS) wavelength bands, but the filter unit (130) may also be configured to selectively transmit only light signals in a narrower wavelength band.

[0084] This is to overcome the limitation of wavelength resolution according to adjacent optical signals, as explained above, especially in the ultraviolet wavelength band, in the case of the first spectrometer, and to perform spectroscopy of optical signals with high sensitivity.

[0085] Thus, through the second spectrometer (120), as an optical signal of the second wavelength band, an optical signal of the ultraviolet (UV) and visible light (VIS) wavelength bands can be received, or an optical signal of a narrower wavelength band among the ultraviolet and visible light wavelength bands can be selectively received (step S34).

[0086] That is, through the second spectrometer (120), it is possible to simultaneously transmit an optical signal in the visible light (VIS) wavelength band and measure the intensity in the corresponding wavelength band (step S34). However, in the case where the second spectrometer (120) transmits an optical signal in the visible light (VIS) wavelength band together with an optical signal in the ultraviolet wavelength band, it can be used more effectively, as described below, particularly for determining the replacement time of the viewing window (30).

[0087] As described above, the spectroscopic module (100) receives optical signals through the first spectrometer (110) and the second spectrometer (120). Examples of optical signals received in this manner are described below.

[0088] Fig. 4 is a graph illustrating an optical signal spectrum that can be monitored using the spectroscopic module of Fig. 2.

[0089] That is, FIG. 4 is an example showing a signal received through the first spectrometer (110) and the second spectrometer (120) for a hydrogen chloride / nitrogen / ammonia (SiH4 / N2 / NH3) plasma emission optical signal.

[0090] As can be seen from FIG. 4, in the case of the first spectrometer (110), it can be confirmed that simultaneous monitoring of multiple emission optical signals is possible for the entire illustrated wavelength band (400 nm to 1,000 nm).

[0091] In contrast, in the case of the second spectrometer (120), it can be confirmed that selective monitoring of a small number of emission light signals is possible only for a specific wavelength band (near 630 nm or near 650 nm). At this time, in the case of FIG. 4, the monitoring characteristics of the emission light signal according to the type of spectrometer are confirmed only for a predetermined wavelength range (400 nm to 1,000 nm), and as previously described, the second spectrometer (120) in the present embodiment mainly monitors the emission light signal of the visible light (VIS) and ultraviolet (UV) bands, which are the second wavelength bands.

[0092] Furthermore, when the filter unit (130) in the second spectrometer (120) includes an ultra-narrow band filter, effective spectroscopy with adjacent wavelength signals can be implemented for a narrower wavelength band.

[0093] In relation to this, FIGS. 5a and 5b are graphs illustrating the results of spectroscopically analyzing adjacent wavelength signals using the spectroscopic module of FIG. 2.

[0094] That is, referring to FIGS. 5a and 5b, for example, as a result of spectroscopically analyzing a plasma emission light signal in which hydrogen and nitrogen coexist through the spectroscopic module (100), it can be confirmed that simultaneous monitoring of multiple emission light signals is possible for the entire illustrated wavelength band (620 nm to 665 nm) through the first spectrometer (110).

[0095] In contrast, in the case of the second spectrometer (120), a filter unit (130) is applied to transmit only specific wavelengths, so that monitoring of a small number of emission light signals can be selectively performed only for a specific wavelength band (625-635 nm band or 655-660 nm band).

[0096] However, when the filter unit (130) is applied as an ultra-narrow band filter that transmits only the H-alpha wavelength band, as shown in FIG. 5b, it can be confirmed that accurate and effective spectroscopy is possible for the signal (656.4 nm) of the H-alpha wavelength band as well as the nitrogen (N) signal (654.9 nm and 658.5 nm), which is a signal of an adjacent wavelength band.

[0097] Therefore, by selecting the filter unit (130) applied to the second spectrometer (120) so that only signals in the wavelength band of the measurement target can be measured, effective spectroscopy is possible even with very adjacent signals.

[0098] As described above, the spectroscopic module (100) can perform spectroscopic analysis by simultaneously using the first spectrometer (110) and the second spectrometer (120) to receive optical signals of the entire wavelength band and selectively receive only optical signals of a specific wavelength band in a relatively very narrow region.

[0099] However, the above-described exemplary description is intended to explain the characteristics of the second spectrometer (120), and as previously explained, high wavelength resolution and sensitivity are required to measure emission light signals mainly in the ultraviolet band, so in the present embodiment, light signals in the ultraviolet wavelength band are mainly received and spectroscopically analyzed through the second spectrometer (120). Of course, as already explained, it is also possible to receive and spectroscopically analyze light signals in the visible light wavelength band.

[0100] Furthermore, in the case of the second spectrometer (120) in this embodiment, changes in the intensity of the emission signal can also be measured relatively accurately.

[0101] In relation to this, FIGS. 6a and 6b are graphs illustrating a state in which a wavelength signal changes when the flow rate of silane (SiH4) gas changes through spectroscopy using the spectroscopy module of FIG. 2.

[0102] That is, in the case of Fig. 6a, when the flow rate of silane (SiH4) gas is varied, this is the result of measuring the signal change of H-alpha according to the variation in the flow rate of the silane gas through the first spectrometer (110).

[0103] In contrast, in the case of Fig. 6b, when the flow rate of silane (SiH4) gas is varied, the result is the measurement of the signal change of H-alpha according to the variation of the flow rate of the silane gas through the second spectrometer (120).

[0104] Referring to FIG. 6a, in the case of the first spectrometer (110), since the nitrogen (N2) signal with a fixed flow rate is measured as a superimposed value, it can be confirmed that there is a limitation in that the change in the amount of hydrogen (H) contained in the silane gas with a variable flow rate is not reflected.

[0105] However, referring to FIG. 6b, it can be confirmed that, relatively speaking, in the case of the second spectrometer (120), particularly the second spectrometer (120) including an ultra-narrow band filter as a filter unit (130) that transmits only the H-alpha wavelength band as described above, the change in the intensity of the H emission signal according to the change in the flow rate of the precursor containing H can be measured more accurately. That is, it can be confirmed that the H-alpha signal increases as the flow rate of the precursor increases from 90 sccm to 290 sccm.

[0106] That is, when performing spectroscopy by additionally using the second spectrometer (120) as in the present embodiment, spectroscopy can be effectively performed between adjacent signals, and accordingly, the intensity change state of a specific signal can also be clearly measured.

[0107] As described above, when optical signals of the first and second wavelength bands are received through the spectral module (100), optical signals according to a specific frequency band are detected through the detection unit (200).

[0108] That is, referring to FIGS. 2 and 3, based on the optical signal received from the spectroscopic module (100), the detection unit (200) detects an optical signal according to each frequency band (step S40).

[0109] At this time, the optical signal detection in the detection unit (200) selectively detects the necessary signal or information by considering the judgment target in the subsequent diagnosis unit (300), and this is described in detail as follows.

[0110] First, the first optical signal detection unit (210) of the detection unit (200) detects both the optical signals in the ultraviolet, visible, and infrared wavelength bands received from the first spectrometer (110) and the optical signals in the ultraviolet and visible wavelength bands received from the second spectrometer (120) (step S41).

[0111] That is, the first optical signal detection unit (210) obtains information about the optical signal spectrum, that is, information about the intensity of the optical signal for each wavelength, for all wavelength bands of optical signals detected through the spectroscopic module (100), and ultimately obtains information about the characteristics of the optical signal itself in the wavelength range to be monitored.

[0112] Accordingly, the information detected by the first optical signal detection unit (210) is provided to the process judgment unit (310) described below.

[0113] In addition, the second optical signal detection unit (220) of the detection unit (200) detects whether the optical signal in the ultraviolet and visible light wavelength band received from the first spectrometer (110) and the optical signal in the ultraviolet and visible light wavelength band received from the second spectrometer (120) are shifted relative to the optical signal in the ultraviolet and visible light wavelength band received from the second spectrometer (120) based on the optical signal in the ultraviolet and visible light wavelength band received from the first spectrometer (110) (step S42).

[0114] And, information on the movement of the optical signal in the ultraviolet and visible light wavelength band detected by the second optical signal detection unit (220) is provided to the correction determination unit (320) described later.

[0115] Furthermore, the third optical signal detection unit (230) of the detection unit (200) detects the transmittance of the optical signal in the ultraviolet and visible light wavelength bands received from the first spectrometer (110) and the transmittance of the optical signal in the ultraviolet and visible light wavelength bands received from the second spectrometer (120) (step S43).

[0116] As described above, in the case of the second spectrometer (120), an optical signal in the ultraviolet wavelength band is received, but an optical signal in some visible light wavelength bands can also be selectively received, and the optical signal in the visible light wavelength band received in this way is detected through the third optical signal detection unit (230).

[0117] Thus, information about the optical signal of the visible light and ultraviolet wavelength band detected by the third optical signal detection unit (230), that is, information about the optical signal of the wavelength band commonly acquired by the first spectrometer (110) and the second spectrometer (120), is provided to the replacement determination unit (300).

[0118] As described above, through the detection unit (200), an optical signal of a required wavelength band is selectively detected from the optical signal of the wavelength band received from the spectroscopic module (100), and the detected information is provided to the diagnosis unit (300).

[0119] Accordingly, referring to FIGS. 2 and 3, the diagnostic unit (300) performs a necessary judgment based on the optical signal of each wavelength band detected through the detection unit (200) (step S50).

[0120] At this time, the specific judgment contents in the above diagnostic unit (300) are explained as follows.

[0121] First, the process judgment unit (310) determines the end point of the plasma process based on the optical signal detected by the first optical signal detection unit (210) (step S51).

[0122] That is, the first optical signal detection unit (210) detects optical signals in the ultraviolet, visible, and infrared wavelength bands received through the first spectrometer (110), and simultaneously detects optical signals in the ultraviolet and visible wavelength bands received through the second spectrometer (120). At this time, in the case of the second spectrometer (120), as described above, it is also possible to detect optical signals in an ultra-narrow band of a specific band.

[0123] Thus, in the process judgment unit (310), information on the components of the gas included in the plasma emission optical signal (20) can be confirmed from the characteristics of the optical signal in the entire wavelength band of ultraviolet, visible, and infrared rays, i.e., the characteristics of the intensity of the optical signal for each wavelength.

[0124] In particular, since the second spectrometer (120) can more accurately obtain the characteristics of the intensity of a specific wavelength-specific optical signal in the ultraviolet region with high sensitivity, the spectral effect between adjacent optical signals is improved, and information on the components of the gas included in the plasma emission optical signal (20) can be more accurately confirmed.

[0125] Accordingly, the process judgment unit (310) can check the characteristics of the type and intensity of the gas in the currently occurring plasma process based on the characteristics of the intensity of the optical signal for each wavelength, and can thereby determine the end point of the plasma process.

[0126] Of course, the process judgment unit (310) can obtain information on the progress status of the plasma process in addition to the end point of the plasma process, but since the end point is a particularly important point in the process, it may be most important to determine the end point of the plasma process.

[0127] In addition, the above correction judgment unit (320) determines the alignment correction time point, which is the time point when correction of the alignment of the first spectrometer (110) is required, based on information about the movement state of the optical signal detected by the second optical signal detection unit (220) (step S52).

[0128] In relation to this, FIGS. 7a and 7b are schematic diagrams for explaining the wavelength shift state of an optical signal according to the alignment error of the first spectrometer of FIG. 2.

[0129] As in Fig. 7a, when the first spectrometer (110) has an alignment error in at least one of the first to third directions (X, Y, Z), as in Fig. 7b, there is a problem in that the received wavelength shifts relatively significantly in both the long wavelength and short wavelength directions.

[0130] In contrast, in the case of the second spectrometer (120), when the incident angle changes due to an alignment error between the lens, transmission filter, and detector constituting the second spectrometer (120), the wavelength of the observed optical signal only slightly shifts toward a shorter wavelength, as in Equation (1) below.

[0131]

[0132] At this time, λ θ is the optical signal wavelength that is incorrectly measured due to alignment error, λ0 is the original optical signal wavelength, n0 is the refractive index of the optical signal transmission medium (air), n * is the refractive index of the bandpass filter, and θ is the alignment error angle.

[0133] That is, in the above equation (1), when assuming that an alignment error of 1 degree occurs for an optical signal having a wavelength of 500 nm, the wavelength shift is only 0.05 nm, so it can be confirmed that the wavelength shift due to the alignment error in the second spectrometer (120) is much smaller than the wavelength shift due to the alignment error in the first spectrometer (110).

[0134] Finally, in the above correction judgment unit (320), when the wavelength of the optical signal shifts compared to the wavelength of the optical signal observed at the initial stage of installation, for the signals of the visible light and ultraviolet wavelength bands commonly detected by the first spectrometer (110) and the second spectrometer (120), it can be determined that the alignment for the first spectrometer (110) must be corrected.

[0135] This is because the wavelength shift of the optical signal is not caused by the second spectrometer (120), but by the first spectrometer (110).

[0136] Thus, if the optical signal wavelength shifts by more than the preset amount of movement, it is determined that alignment correction of the first spectrometer (110) is necessary, and alignment correction of the first spectrometer (110) is performed.

[0137] Furthermore, the replacement determination unit (330) determines the replacement time of the sight window (30) based on the transmittance of the optical signal detected by the third optical signal detection unit (230) (step S53).

[0138] That is, the replacement time of the sight glass (30) is determined based on the transmittance of the optical signal in the visible light and ultraviolet wavelength bands received from the first spectrometer (110) detected through the third optical signal detection unit (230) and the transmittance of the optical signal in the visible light and ultraviolet wavelength bands received from the second spectrometer (120).

[0139] As described above, the above-mentioned window (30) is a window through which the plasma emission light signal (20) passes and is provided to the spectroscopic module (100), and must have high transparency to effectively provide the emission light signal (20).

[0140] However, as the plasma process continues, the viewing window (30) may become contaminated, and due to this contamination, the transmittance of the emitted light signal (20) provided through the viewing window (30), i.e., the intensity of the light, may decrease.

[0141] In relation to this, Fig. 8a is a graph illustrating the state of change in transmittance by wavelength according to contamination of the sight glass of Fig. 2, and Fig. 8b is a graph for explaining the timing of replacement of the sight glass according to change in sensitivity of the spectral module of Fig. 2.

[0142] That is, referring to Fig. 8a, as the sight glass (30) is contaminated, it can be confirmed that a rapid change in transmittance occurs in a relatively short wavelength range (200 nm to 500 nm). This is a phenomenon that commonly occurs in the first spectrometer (110) as well as the second spectrometer (120). In the case of contamination of the sight glass (30), it is caused by the deposition of organic or inorganic materials on the surface of the sight glass made of quartz, and as shown in Fig. 8a, it can be confirmed that a tendency for a decrease in long wavelength signals compared to short wavelength signals ultimately occurs through a rapid change in transmittance in a relatively short wavelength range.

[0143] Accordingly, since the change in transmittance due to contamination of the above-mentioned window occurs not only in the first spectrometer (110) but also in the second spectrometer (120), in order to more accurately obtain the tendency of the decrease in long-wavelength signals compared to short-wavelength signals, it is necessary to obtain optical signals in a wavelength band including visible light as well as ultraviolet rays, which are simply in the short-wavelength range, through the second spectrometer (120).

[0144] Thus, by simultaneously using the transmittance obtained from the first spectrometer (110) that has already obtained optical signals for all wavelength bands and the transmittance obtained through the second spectrometer (120), the tendency of the long wavelength signal reduction compared to the short wavelength signal as in FIG. 8a can be confirmed more accurately.

[0145] That is, as in FIG. 8b, the change in transmittance in the ultraviolet and visible light wavelength bands obtained from the first spectrometer (110) and the change in transmittance in the ultraviolet and visible light wavelength bands obtained from the second spectrometer (120) are simultaneously monitored, and the replacement determination unit (330) determines the replacement time of the sight glass (30) based on the contamination status of the sight glass (30).

[0146] Thus, when the light transmittance of the above-described window (30) becomes lower than the preset standard for the contamination status, the above-described window (30) is replaced.

[0147] Meanwhile, reception of an optical signal through the first spectrometer (110) may be performed through an optical fiber, and reception of an optical signal through the second spectrometer (120) may be performed only through the viewing window (30).

[0148] In this case, by comparing the difference between the transmittance of the optical signal received from the first spectrometer (110) and the transmittance of the optical signal received from the second spectrometer (120) from the start of measurement, it is possible to determine the time to replace the optical fiber or the time to replace the viewing window.

[0149] That is, if the transmittance of the optical signal received from the first spectrometer (110) is lower than the transmittance of the optical signal received from the second spectrometer (120), it can be determined that the optical fiber needs to be replaced. Conversely, if the opposite is true, it can be determined that the viewing window needs to be replaced.

[0150] As described above, through the diagnostic unit (300), information on the optical signal detected by the detection unit (200) can be selectively utilized to determine various states of the plasma process, particularly the end point, the calibration point of the first spectrometer (110), and further the replacement point of the viewing window (30). In addition, determination can also be made on the replacement point of the optical fiber considering the connection state of the first spectrometer (110).

[0151] According to the embodiments of the present invention as described above, by simultaneously using a first spectrometer that performs diffraction spectroscopy and a second spectrometer that performs transmission spectroscopy, an optical signal is detected using the first spectrometer in the visible light (VIS)-infrared (IR) wavelength band, and an optical signal is detected using the second spectrometer in the ultraviolet (UV)-visible light (VIS) wavelength band, thereby enabling detection of an optical signal in the entire band with high sensitivity and reliability.

[0152] Thus, by overcoming the resolution limitations of the first spectrometer in a region where adjacent optical signals exist, such as ultraviolet bands or metal atom emission signals, more accurate and reliable optical signal spectral detection is possible.

[0153] In particular, in the case of the second spectrometer, a filter section that can transmit only wavelengths of a specific band is included, so that an optical signal of a specific wavelength band to be monitored can be selectively obtained.

[0154] Accordingly, the end point of the plasma process can be determined more accurately and with high reliability through spectral detection of optical signals in the entire band as described above as well as detection of optical signals in a specific wavelength band.

[0155] In addition, since the first spectrometer tends to shift in wavelength as an alignment error exists, if the wavelength of an optical signal received through the first spectrometer shifts relatively significantly for a specific wavelength band where the first spectrometer and the second spectrometer can be observed together, it is determined that this is the calibration point of the first spectrometer, and calibration of the spectroscopic module can be performed.

[0156] Furthermore, when receiving a plasma emission optical signal through a sight glass, the transmittance of the received optical signal decreases depending on contamination of the sight glass. Since this decrease in transmittance of the optical signal commonly occurs in the first spectrometer and the second spectrometer, it is possible to monitor this and determine the timing of replacement of the sight glass.

[0157] Thus, in monitoring the plasma process status, in addition to simply accurately judging the process end point, information on the alignment status of the spectroscopic module and the contamination status of the viewing window can also be monitored simultaneously, thereby further improving the accuracy and reliability of judging the process end point.

[0158] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A spectroscopic module that receives an optical signal emitted from a plasma process; A detection unit that detects an optical signal according to a frequency band based on an optical signal received from the above spectral module; and Based on the above-detected optical signal, a diagnostic unit is included that determines the status of the plasma process or determines the timing of correction of the spectroscopic module. A spectroscopic system characterized in that the above spectroscopic module includes a first spectrometer that receives an optical signal of a first wavelength band by performing diffraction spectroscopy, and a second spectrometer that receives an optical signal of a second wavelength band by performing transmission spectroscopy.

2. In paragraph 1, The optical signal of the above first wavelength band is an optical signal of the ultraviolet (UV), visible light (VIS) and infrared (IR) wavelength bands, A spectroscopic system characterized in that the optical signal of the second wavelength band is an optical signal of the ultraviolet (UV) and visible light (VIS) wavelength bands.

3. In the second paragraph, the detection unit, A spectroscopic system characterized by including a first optical signal detection unit that detects optical signals in the ultraviolet, visible, and infrared wavelength bands received from the first spectrometer and optical signals in the ultraviolet and visible wavelength bands received from the second spectrometer.

4. In the third paragraph, the diagnostic unit, A spectroscopic system characterized by including a process determination unit that determines the end point of the plasma process based on the optical signal detected by the first optical signal detection unit.

5. In the second paragraph, the second spectrometer, A spectroscopic system characterized in that it further includes a filter section that selectively transmits only wavelengths of a specific band belonging to the ultraviolet (UV) and visible light (VIS) wavelength bands.

6. In the second paragraph, the detection unit, A spectroscopic system characterized by including a second optical signal detection unit that detects whether an optical signal in the ultraviolet and visible light wavelength band received from the first spectrometer is shifted with respect to an optical signal in the ultraviolet and visible light wavelength band received from the second spectrometer.

7. In paragraph 6, the diagnostic unit, A spectroscopic system characterized by including a correction judgment unit that determines the alignment correction time of the first spectrometer based on the movement state of the optical signal detected by the second optical signal detection unit.

8. In paragraph 2, A spectroscopic system further comprising a viewing window interposed between the process chamber in which the plasma process is performed and the spectroscopic module, through which an optical signal emitted from the plasma process is transmitted.

9. In the 8th paragraph, the detection unit, A spectroscopic system characterized by including a third optical signal detection unit that detects the transmittance of an optical signal in the ultraviolet and visible light wavelength bands received from the first spectrometer and the transmittance of an optical signal in the ultraviolet and visible light wavelength bands received from the second spectrometer.

10. In paragraph 9, the diagnostic unit, A spectroscopic system characterized by including a replacement determination unit that determines the replacement time of the viewing window based on the transmittance of the optical signal detected by the third optical signal detection unit.

11. In paragraph 8, The above first spectrometer receives the optical signal through an optical fiber, A spectroscopic system characterized in that the second spectrometer receives the optical signal through the viewing window.

12. In paragraph 11, By comparing the difference between the transmittance of the optical signal received from the first spectrometer and the transmittance of the optical signal received from the second spectrometer, A spectroscopic system characterized in that the timing of replacement of the optical fiber or the timing of replacement of the viewing window is determined.

13. A step of receiving an optical signal emitted from a plasma process through a spectroscopic module; A step of detecting an optical signal according to a frequency band based on the received optical signal; and Based on the above-detected optical signal, a step of determining the status of the plasma process or determining the timing of correction of the spectroscopic module is included. A process diagnostic method, characterized in that the above spectral module includes a first spectrometer that receives an optical signal of a first wavelength band by diffraction spectroscopy, and a second spectrometer that receives an optical signal of a second wavelength band by transmission spectroscopy.

14. In the step of determining the status of the plasma process in paragraph 13, A process diagnostic method characterized in that the end point of the plasma process is determined based on the optical signal for each wavelength band of the detected optical signal.

15. In the 13th paragraph, the detected optical signal is A process diagnostic method characterized by comprising optical signals in the ultraviolet, visible, and infrared wavelength bands received from the first spectrometer and optical signals in the ultraviolet and visible wavelength bands received from the second spectrometer.

16. In the step of determining the calibration time of the spectral module in paragraph 13, A process diagnostic method characterized in that the alignment correction time of the first spectrometer is determined based on the state in which the optical signal received from the first spectrometer among the above spectrometer modules moves with respect to the optical signal received from the second spectrometer among the above spectrometer modules.

17. In paragraph 16, A process diagnostic method, characterized in that the optical signals received from the first spectrometer and the second spectrometer are optical signals in the ultraviolet and visible light wavelength bands.

18. In paragraph 13, The above optical signal is received by the spectroscopic module through the viewing window, A process diagnostic method further comprising a step of determining the replacement time of the viewing window based on the transmittance of the optical signal received from the first spectrometer among the above spectrometer modules and the transmittance of the optical signal received from the second spectrometer among the above spectrometer modules.

19. In paragraph 18, A process diagnostic method, characterized in that the transmittance of the optical signal received from the first spectrometer and the second spectrometer is the transmittance of the optical signal in the visible light and ultraviolet wavelength bands.

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