Method of processing substrate

Abstract

A substrate processing method according to one aspect of the present invention is a substrate processing method using a substrate processing apparatus comprising: a process chamber having a reaction space formed therein; a substrate support member coupled to the process chamber; a gas injection member coupled to the process chamber to face the substrate support member and for injecting process gas into the reaction space; a remote plasma generator spaced apart from the process chamber and configured to form a plasma atmosphere for activating process gas on a gas supply line communicating with the gas injection member; and a monitoring member for real-time monitoring of the state of plasma generated from the remote plasma generator, wherein the method includes a cleaning step of cleaning the path through which the process gas flows according to the real-time monitoring result by the monitoring member.

Description

Technology Field

[0001] The present invention relates to semiconductor manufacturing, and more specifically, to a substrate processing method using a substrate processing apparatus. Background Technology

[0002] To manufacture semiconductor devices, various processes are performed in a substrate processing apparatus under a vacuum atmosphere. For example, a substrate may be loaded into a process chamber, and processes such as depositing a thin film or etching a thin film on the substrate may be carried out. Here, the substrate is supported by a substrate support installed inside the process chamber, and process gas can be injected onto the substrate through a gas injection unit installed on the upper part of the substrate support.

[0003] Activation of process gases using plasma is required to enhance reactivity and ensure precise process control during substrate processing. Furthermore, instead of generating plasma directly within the process chamber, remote plasma is generated within a remote plasma generator (RPG) to activate the process gases, thereby reducing substrate damage caused by direct plasma.

[0004] However, residues remain due to the reaction of precursors by the remote plasma, and these residues pose a problem that reduces process reliability. Furthermore, there is a limitation in that there is no way to evaluate the chamber environment, so process problems can only be identified belatedly through post-processing measurements. The problem to be solved

[0005] The present invention aims to solve various problems, including those mentioned above, by providing a substrate processing method equipped with a real-time monitoring system to analyze the presence of internal chamber residues causing process problems and the environment for radical formation, and to prevent process accidents in advance by taking corrective measures before starting the process if problems are anticipated during the wafer processing. However, this objective is exemplary and does not limit the scope of the present invention. means of solving the problem

[0006] A substrate processing method according to one aspect of the present invention for solving the above problem comprises: a process chamber having a reaction space formed therein; a substrate support member coupled to the process chamber; a gas injection member coupled to the process chamber to face the substrate support member and for injecting process gas into the reaction space; a remote plasma generator spaced apart from the process chamber and configured to form a plasma atmosphere for activating process gas on a gas supply line communicating with the gas injection member; and a monitoring member for real-time monitoring of the state of plasma generated from the remote plasma generator, wherein the method includes a cleaning step of cleaning the path through which the process gas flows according to the real-time monitoring result by the monitoring member.

[0007] In the above substrate processing method, the cleaning step may be characterized by proceeding with the substrate processing process when the real-time monitoring result by the monitoring unit is within a preset value, and cleaning the path through which the process gas flows when the real-time monitoring result deviates from the preset value.

[0008] In the above substrate processing method, the monitoring unit may be positioned between the remote plasma generator and the process chamber and may include an optical emission spectrometer (OES) or a residual gas analyzer (RGA) for monitoring the state of the plasma.

[0009] In the above substrate processing method, the real-time monitoring result by the monitoring unit may be the real-time monitoring result by the monitoring unit during the following steps: supplying NH3 gas and NF3 gas to the remote plasma generator and forming a plasma atmosphere to activate the NH3 gas and NF3 gas; and supplying the activated NH3 gas and NF3 gas to the reaction space through the gas injection unit; and then supplying only argon (Ar) gas to the remote plasma generator and forming a plasma atmosphere to activate the argon (Ar) gas; and supplying the activated argon (Ar) gas to the reaction space through the gas injection unit. The real-time monitoring result by the monitoring unit may include the peak intensity of the H peak or NH peak analyzed in real-time using an Optical Emission Spectroscopy (OES) spectroscopy to analyze the state of the plasma.

[0010] In the above substrate processing method, the cleaning step may include: a step of activating the hydrogen or helium gas by supplying hydrogen or helium gas to the remote plasma generator and forming a plasma atmosphere; and a step of cleaning the path through which the hydrogen or helium gas flows by supplying the activated hydrogen or helium gas to the reaction space through the gas injection unit.

[0011] In the above substrate processing method, the cleaning step may include: a step of heating the hydrogen or helium gas by supplying the hydrogen or helium gas to the remote plasma generator heated to a plasma atmosphere; and a step of cleaning the path through which the hydrogen or helium gas flows by supplying the heated hydrogen or helium gas to the reaction space through the gas injection unit.

[0012] In the above substrate processing method, the cleaning step may include: a step of activating the gas containing the halogen element by supplying the gas containing the halogen element to the remote plasma generator and forming a plasma atmosphere; and a step of cleaning the path through which the gas containing the halogen element flows by supplying the activated gas containing the halogen element to the reaction space through the gas injection unit. The gas containing the halogen element may include either NF3 or F2. In the above substrate processing method, the cleaning step may be performed before the step of placing the substrate on the substrate support.

[0013] The above substrate processing method further performs a stabilization step for stabilizing a substrate processing device according to the real-time monitoring result by the monitoring unit, wherein the stabilization step may include a step of activating the argon (Ar) gas by supplying argon (Ar) gas to the remote plasma generator and forming a plasma atmosphere.

[0014] In the above substrate processing method, the step of activating the argon (Ar) gas may be characterized by being performed for 30 seconds or more. Effects of the invention

[0015] According to the substrate processing method of some embodiments of the present invention as described above, a substrate processing method can be implemented that prevents process accidents in advance by installing a real-time monitoring system to analyze the presence of internal chamber residues causing problems in the process and the environment for radical formation, and by taking corrective measures before starting the process if a problem is anticipated in the wafer process. Of course, the scope of the present invention is not limited by these effects. Brief explanation of the drawing

[0016] FIG. 1 is a schematic cross-sectional view showing a substrate processing apparatus for illustrating a substrate processing method according to some embodiments of the present invention. FIG. 2 is a flowchart showing a substrate processing method according to one embodiment of the present invention. FIG. 3 is a flowchart showing a substrate processing method according to another embodiment of the present invention. Figure 4 is a diagram showing the analysis results of Optical Emission Spectroscopy (OES) according to the process sequence of atomic layer etching (ALR). Figure 5 shows the results of analyzing the residue formed by Ar + NH3 + NF3 plasma using a mass spectrometer (RGA; Residual Gas Analyzer). Figure 6 shows the change in peak intensity of the Optical Emission Spectroscopy (OES) as the process progresses. Figure 7 is a graph showing the residue removal pattern according to the treatment time of NF3 plasma. Figure 8 is a graph evaluating the residue removal time using hydrogen, which has high thermal conductivity. Figure 9 is a graph summarizing the results of the residue removal evaluation according to the hydrogen flow of Figure 8. Figure 10 shows the H peak intensity of the optical emission spectrometer (OES) over time during the argon ignition process. Figure 11 is a graph showing the intensity of the NH peak and H peak in Optical Emission Spectroscopy (OES) as a result of performing three consecutive cycles by combining a 30-second argon ignition step and a 30-second hydrogen flow immediately after the main etching process. FIG. 12 is a graph showing the particle generation pattern when the substrate processing method according to the comparative example and embodiment of the present invention is applied. FIG. 13 is a graph showing the first wafer effect when the substrate processing method according to the comparative example and embodiment of the present invention is applied. Specific details for implementing the invention

[0017] Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0018] The embodiments of the present invention are provided to more fully explain the invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the invention is not limited to the following embodiments. Rather, these embodiments are provided to make the disclosure more faithful and complete and to fully convey the spirit of the invention to those skilled in the art. In addition, the thickness or size of each layer in the drawings is exaggerated for convenience and clarity of explanation.

[0019] FIG. 1 is a schematic cross-sectional view showing a substrate processing apparatus (100) for showing a substrate processing method according to some embodiments of the present invention.

[0020] Referring to FIG. 1, the substrate processing device (100) may include a process chamber (110), a gas injection unit (120), a substrate support unit (130), and a remote plasma generator (150).

[0021] More specifically, a reaction space (112) in which a substrate (S) can be processed may be formed in the process chamber (110). The process chamber (110) may be connected to a vacuum pump (not shown) through an exhaust pipe (114) to create a vacuum atmosphere. Furthermore, the process chamber (110) may include an inlet / outlet for loading the substrate (S) into or unloading it from the reaction space (112), and a gate structure (not shown) for opening and closing the inlet / outlet. The process chamber (110) may be provided in various shapes and may include, for example, a side wall portion defining the reaction space (112) and a cover portion located on the top of the side wall portion, such as a top lead.

[0022] A gas injection unit (120) may be coupled to the process chamber (110) to supply process gases supplied from outside the process chamber (110) into the reaction space (112). The gas injection unit (120) may be coupled to the process chamber (110) so as to face the substrate support (130). For example, the gas injection unit (120) may be installed on the upper part of the process chamber (110) to inject process gas onto a substrate (S) placed on the substrate support (130). More specifically, the gas injection unit (120) may include an inlet through which process gas is introduced via a gas pipe (154), a blocker plate for dispersing the process gas that has passed through the inlet, and a distribution plate for injecting the process gas into the reaction space (112).

[0023] In some embodiments, the gas injection unit (120) may have various forms, such as a shower head or a nozzle. If the gas injection unit (120) is in the form of a shower head, the gas injection unit (120) may be coupled to the process chamber (110) in a manner that partially covers the upper part of the process chamber (110). For example, the gas injection unit (120) may be coupled to the cover or side wall of the process chamber (110).

[0024] A substrate support member (130) may be coupled to a process chamber (110) to support a substrate (S) within a reaction space (112). For example, the substrate support member (130) may be installed in the process chamber (110) facing a gas injection member (120). The top plate shape of the substrate support member (130) generally corresponds to the shape of the substrate (S), but is not limited thereto and may be provided in various shapes larger than the substrate (S) so as to stably seat the substrate (S).

[0025] Furthermore, the shaft (135) of the substrate support (130) may be connected to an external motor (not shown) to enable vertical movement, and in this case, a bellows tube (not shown) may be connected between the process chamber (110) and the shaft (135) to maintain airtightness. Furthermore, since the substrate support (130) is configured to place a substrate (S) thereon, it may be referred to as a substrate mounting part, a susceptor, etc.

[0026] In some embodiments, the substrate support (130) may further include an electrostatic electrode to apply electrostatic force to the substrate (S) and fix it on top thereof. In this case, the electrostatic electrode may receive DC power from an electrostatic power supply.

[0027] A remote plasma generator (150) may be positioned outside the process chamber (110) and connected to a gas injection unit (120) to supply process gases to the process chamber (110). For example, the remote plasma generator (150) may activate some of the process gases by forming a plasma atmosphere inside.

[0028] For example, the remote plasma generator (150) can activate the first process gas, the second process gas, or the third process gas and supply it to the process chamber (110). The process gas can be introduced into the remote plasma generator (150) through the gas pipe (154).

[0029] Furthermore, a plasma power supply (140) for applying power may be connected to the remote plasma generator (150). For example, the plasma power supply (140) may each include at least one RF power supply to apply at least one RF (radio frequency) power.

[0030] For example, the remote plasma generator (150) can form a plasma atmosphere using an inductive coupled plasma (ICP) method, a capacitive coupled plasma (CCP) method, a toroidal plasma method, a microwave (MW) method, etc.

[0031] The monitoring unit (145) is positioned between the remote plasma generator (150) and the process chamber (110) to monitor the state of the plasma generated from the remote plasma generator (150) in real time.

[0032] The monitoring unit (145) may include, for example, an optical emission spectroscopy (OES) and / or a residual gas analyzer (RGA) for monitoring the state of the plasma.

[0033] An optical emission spectrometer (OES) can monitor the intensity or amount of plasma light by being equipped with an optical fiber. The optical emission spectrometer (OES) can be configured to detect light emitted when an electron in a relatively high-energy state transitions to a low-energy state, utilizing the discontinuous electron energy levels of atoms and ions. Since the ionization phenomenon caused by plasma follows the emission phenomenon, a substrate processing device that performs processing using plasma can be equipped with an optical emission spectrometer (OES) to monitor the state of plasma generation. In this case, the monitoring unit (140) is not limited to an optical emission analyzer (OES) but may be configured to include a camera that monitors the intensity or amount of plasma light.

[0034] A mass spectrometer (RGA) can chemically analyze a sample gas. The sample gas is ionized, and the ions are separated based on the mass-to-charge ratio by a quadrupolar electric field using a combination of direct current (DC) and RF potential. The mass spectrometer (RGA) measures the ion flux relative to the mass-to-charge ratio and thereby provides a specific chemical analysis of the sample gas.

[0035] The monitoring unit (145) performs process monitoring below the remote plasma generator (150). For example, the monitoring unit (145) can be mounted on a waveguide port of the remote plasma generator (150). That is, the plasma is diagnosed using an emission spectrometer (OES) and / or a mass spectrometer (RGA) directly below the remote plasma generator (150), and analysis of plasma species and changes according to changes in process conditions is possible.

[0036] A substrate processing device (100) for performing a substrate processing method according to the technical concept of the present invention feeds back the real-time analysis results of the monitoring unit (145) to the equipment to perform the process in an optimal process environment.

[0037] Hereinafter, a substrate processing method according to embodiments of the present invention is described with reference to the substrate processing device (100). The substrate processing method in the present invention is characterized by analyzing the presence of equipment residue and the radical formation rate collected by the monitoring unit (145) to determine whether the equipment environment is normal, and in the case of abnormality, feeding back to the equipment so that appropriate measures can be taken and the process can proceed.

[0038] FIGS. 2 and FIGS. 3 are flowcharts showing a substrate processing method according to some embodiments of the present invention. The substrate processing method illustrated in FIG. 2 is a substrate processing method that can be applied when the substrate is loaded onto a substrate support, and the substrate processing method illustrated in FIG. 3 is a substrate processing method in an idle state that can be applied when the substrate is not loaded onto a substrate support.

[0039] Referring to FIGS. 1 to 3, a substrate processing method according to some embodiments of the present invention includes a cleaning step (S110) for cleaning a path through which process gas flows according to a real-time monitoring result by a monitoring unit (145).

[0040] The cleaning step (S110) may include a step of proceeding with the substrate processing process without cleaning if the real-time monitoring result by the monitoring unit (145) is within a preset value, but cleaning the path through which the process gas flows if the real-time monitoring result deviates from the preset value.

[0041] The above substrate processing process may include, for example, an atomic layer removal (ALR) process, but the technical concept of the present invention is not limited to a specific substrate processing process. However, for the sake of convenience of understanding, an atomic layer removal method using NH3 gas and NF3 gas will be assumed and described below as an exemplary substrate processing process.

[0042] Referring to FIGS. 1 and 2, a substrate processing method according to one embodiment of the present invention may place a substrate (S) on a substrate support (130) (S10). For example, in this step (S10), the substrate (S) may be brought into a process chamber (110) and placed on the substrate support (130). In some embodiments, the substrate (S) includes a semiconductor wafer, and a part of a structure for forming a semiconductor device may be formed on the semiconductor wafer.

[0043] Next, a step (S20) is performed in which only an inert gas, such as argon (Ar) gas, is supplied to a remote plasma generator (150) to form a plasma atmosphere and activate the argon (Ar) gas, and the activated argon (Ar) gas is supplied to a reaction space (112) within a process chamber (110) through a gas injection unit (120).

[0044] Next, the argon plasma state described above is monitored in real time by the monitoring unit (145) (S30). For example, the monitoring result by the monitoring unit (145) may include the peak intensity of the H peak or NH peak analyzed in real time by an optical emission spectroscopy (OES) of the plasma state during the step (S20).

[0045] If the intensity of the H peak or NH peak is less than or equal to a preset value as a result of real-time monitoring by the monitoring unit (145), it is determined to be normal and a subsequent substrate processing process can be carried out without performing a separate cleaning step (S110). On the other hand, if the intensity of the H peak or NH peak exceeds a preset value as a result of real-time monitoring by the monitoring unit (145), it is determined to be abnormal and a separate cleaning step (S110) is performed.

[0046] For example, the cleaning step (S110) may include: a step of supplying hydrogen or helium gas to a remote plasma generator (150) and forming a plasma atmosphere to activate the hydrogen or helium gas; and a step of cleaning the path through which the hydrogen or helium gas flows by supplying the activated hydrogen or helium gas to the reaction space (112) through a gas injection unit (120).

[0047] As another example, the cleaning step (S110) may include: a step of heating the hydrogen or helium gas by supplying hydrogen or helium gas to a remote plasma generator (150) heated to a plasma atmosphere; and a step of cleaning the path through which the hydrogen or helium gas flows by supplying the heated hydrogen or helium gas to the reaction space (112) through a gas injection unit (120).

[0048] In the examples described above, hydrogen (H) has a smaller molecular size compared to argon (Ar), so its thermal conductivity is about 10 times higher, making it easy to remove residues by heat. Using gases with small molecular sizes and high thermal conductivity, such as hydrogen (H) and helium (He), can shorten the processing time.

[0049] Meanwhile, if the plasma diagnosis (I) step (S30) is determined to be normal, a reaction gas, e.g., NH3 gas, is supplied to the remote plasma generator (150), and furthermore, an inert gas, argon (Ar) gas, is supplied to form a plasma atmosphere to activate the NH3 gas and Ar gas, and the activated NH3 gas and Ar gas are supplied to the reaction space (112) inside the process chamber (110) through the gas injection unit (120), a step (S40) is performed.

[0050] Next, the plasma state is monitored in real time by the monitoring unit (145) (S50). For example, the monitoring result by the monitoring unit (145) may include the peak intensity of the H peak or NH peak analyzed in real time by an optical emission spectroscopy (OES) of the plasma state during the above step (S40).

[0051] If the intensity of the H peak or NH peak is less than or equal to a preset value as a result of real-time monitoring by the monitoring unit (145), it is determined to be normal and the subsequent substrate processing process can proceed without performing a separate stabilization step (S120). Conversely, if the intensity of the H peak or NH peak exceeds a preset value as a result of real-time monitoring by the monitoring unit (145), it is determined to be abnormal and a separate stabilization step (S120) is performed.

[0052] The above stabilization step (S120) may include a step of supplying argon (Ar) gas to a remote plasma generator (150) and forming a plasma atmosphere to activate the argon (Ar) gas. Specifically, the step of activating the argon (Ar) gas in the stabilization step (S120) may be characterized by performing an argon ignition step for 30 seconds or more. Here, the argon ignition step can be understood as a plasma formation step using argon.

[0053] Meanwhile, if it is determined to be normal in the plasma diagnosis (II) step (S50), an etching gas, e.g., NH3 gas and NF3 gas, is supplied to the remote plasma generator (150), and furthermore, an inert gas, argon (Ar), is supplied to form a plasma atmosphere to activate the NH3 gas, NF3 gas, and Ar gas, and the activated NH3 gas, NF3 gas, and Ar gas is supplied to the reaction space (112) within the process chamber (110) through the gas injection unit (120), and a step (S60) is performed. An atomic layer removal (ALR) process can be performed using the activated etching gas. After the atomic layer removal (ALR) process is performed, the substrate (S) can be unloaded from the substrate support (130) (S70).

[0054] In the plasma diagnosis (II) step (S50), the first wafer effect and process reproducibility can be predicted. In the atomic layer etching (ALR) process, the first wafer effect is caused by changes in the temperature and seasoning state of the plasma generation region inside the remote plasma generator (150). By observing changes in the intensity of the NH and H peaks, which represent the plasma state of the atomic layer etching (ALR) process, in the spectrum of the optical emission spectrometer (OES) which is the monitoring unit (145), the process reproducibility can be predicted. By feeding back to the equipment to compensate for process conditions in real time, process reproducibility can be maintained, or accidents such as stopping the process can be prevented, and the timing of equipment PM can be managed.

[0055] Meanwhile, the substrate processing method illustrated in FIG. 2 can be performed after sequentially loading and unloading a series of substrates onto a substrate support (130). Accordingly, after the second wafer, the plasma diagnostic step (S30, S50) described above is implemented after performing the step of activating the NH3 gas and NF3 gas by supplying NH3 gas and NF3 gas to a remote plasma generator (150) and forming a plasma atmosphere; and the step of supplying the activated NH3 gas and NF3 gas to the reaction space (112) through a gas injection unit (120).

[0056] Referring to FIG. 1 and FIG. 3, a substrate processing method according to another embodiment of the present invention can be performed in an idle state where the substrate (S) is not seated on the substrate support (130).

[0057] Unlike the substrate processing method according to one embodiment of the present invention described with reference to FIG. 2, the substrate processing method according to another embodiment of the present invention described with reference to FIG. 3 is identical except that a separate embodiment is added in the cleaning step (S110), and the other steps are the same.

[0058] Referring to FIG. 3, the argon plasma state implemented in the inert gas activation step (S20) is monitored in real time by a monitoring unit (145) (S30). For example, the monitoring result by the monitoring unit (145) may include the peak intensity of the H peak or NH peak analyzed in real time by an optical emission spectroscopy (OES) of the plasma state during the step (S20).

[0059] If the intensity of the H peak or NH peak is less than or equal to a preset value as a result of real-time monitoring by the monitoring unit (145), it is determined to be normal and a subsequent substrate processing process can be carried out without performing a separate cleaning step (S110). On the other hand, if the intensity of the H peak or NH peak exceeds a preset value as a result of real-time monitoring by the monitoring unit (145), it is determined to be abnormal and a separate cleaning step (S110) is performed.

[0060] For example, the cleaning step (S110) may include: a step of supplying hydrogen or helium gas to a remote plasma generator (150) and forming a plasma atmosphere to activate the hydrogen or helium gas; and a step of cleaning the path through which the hydrogen or helium gas flows by supplying the activated hydrogen or helium gas to the reaction space (112) through a gas injection unit (120).

[0061] As another example, the cleaning step (S110) may include: a step of heating the hydrogen or helium gas by supplying hydrogen or helium gas to a remote plasma generator (150) heated to a plasma atmosphere; and a step of cleaning the path through which the hydrogen or helium gas flows by supplying the heated hydrogen or helium gas to the reaction space (112) through a gas injection unit (120).

[0062] As another example, the cleaning step (S110) may include: a step of supplying a gas containing a halogen element to a remote plasma generator (150) and forming a plasma atmosphere to activate the gas containing the halogen element; and a step of cleaning the path through which the gas containing the halogen element flows by supplying the activated gas containing the halogen element to the reaction space (112) through a gas injection unit (120). The gas containing the halogen element may include either NF3 or F2. In the case of an atomic layer etching (ALR) process, particles are generated by residues containing nitrogen and hydrogen, so residues can be removed by NF3 plasma treatment. If the peak intensity of NH and H related to process residues causing particles exceeds a preset value, the subsequent process is not performed, and the NF3 plasma treatment is performed by feeding back to the equipment, and the subsequent process is performed when the peak intensity of NH and H is below the preset value.

[0063] Below, a substrate processing method according to the technical concept of the present invention is explained using specific experimental data.

[0064] Figure 4 is a diagram showing the analysis results of Optical Emission Spectroscopy (OES) according to the process sequence of atomic layer etching (ALR).

[0065] Referring to FIG. 4, items Ar (I) and Ar (IV) shown in the process sequence of the atomic layer etching (ALR) method correspond to the inert gas activation step (S20) of FIG. 2, item Ar + NH3 (II) corresponds to the reaction gas activation step (S40) of FIG. 2, and item Ar + NH3 + NF3 (III) corresponds to the etching gas activation step (S60) of FIG. 2 as the main etching process.

[0066] When examining the results of optical emission spectroscopy (OES) analysis in the Ar (I) stage, it can be confirmed that NH peaks and H peaks are not observed in the argon plasma. This is because the byproducts of NH3 and NF3 plasma, which are the cause of residue generation, were not present.

[0067] When examining the results of optical emission spectroscopy (OES) analysis in the Ar + NH3(II) and Ar + NH3+ NF3(III) stages, it can be confirmed that NH and H peaks are observed. This is because byproducts of NH3 and NF3 plasma, which are the cause of residue generation, appear.

[0068] Furthermore, looking at the analysis results of the Optical Emission Spectroscopy (OES) in the Ar (IV) stage, it can be confirmed that, unlike the Ar (I) stage, the NH peak and the H peak are observed. This allows us to understand that the NH peak and the H peak are observed in the argon plasma performed with the residue formed in the Ar + NH3 (II) stage and the Ar + NH3 + NF3 (III) stage remaining.

[0069] Figure 5 shows the results of analyzing the residue formed by Ar + NH3 + NF3 plasma using a mass spectrometer (RGA; Residual Gas Analyzer).

[0070] Referring to FIG. 5, the residue formed by the Ar + NH3 + NF3 plasma represents the residue formed in the etching gas activation step (S60) of FIG. 2, and it can be confirmed that it is an N and H related polymer residue such as NH3(HF)3. The polymer residue is a reaction byproduct of the NH3 and NF3 plasma.

[0071] Referring to FIGS. 4 and 5, it can be understood that in the substrate processing method according to an embodiment of the present invention, the occurrence of residue can be confirmed through real-time monitoring system (OES, RGA) analysis. That is, prior to the start of the main etching process (Ar + NH3 + NF3), a strong argon peak appeared in the argon remote plasma, while no hydrogen peak appeared. When NH3 is additionally injected, the argon peak decreases, and as NH3 is ionized, the NH and H peaks appear strongly. When NF3 is additionally injected, the F in NF3 reacts with NH3 and H, causing the NH and H peaks to decrease slightly. Here, NH3(HF) x The formation of a solid polymer was confirmed using a Residual Gas Analyzer (RGA). Even though NH3 and NF3 plasmas were removed after the main etching process, strong peaks of NH and H were observed in the argon remote plasma.

[0072] Figure 6 shows the change in peak intensity of an Optical Emission Spectroscopy (OES) as the process progresses. In Figure 6, the Ar process; Ar+NH3 process; and Ar process proceed first, and the Ar+NH3 process; Ar+NH3+NF3 process; and Ar process proceed sequentially by repeating the cycle three times. The Ar process corresponds to the inert gas activation step (S20) of Figure 2, the Ar+NH3 process corresponds to the reaction gas activation step (S40) of Figure 2, and the Ar+NH3+NF3 process corresponds to the etching gas activation step (S60) of Figure 2.

[0073] Referring to Figure 6, as an initial process, the Ar process; the Ar+NH3 process; and in the Ar process, NF3 was not injected, and only Ar and Ar+NH3 were injected to observe whether any residue remained, and no residue appeared.

[0074] Next, the Ar+NH3 process; Ar+NH3+NF3 process; and Ar process were carried out to inject NF3. At the moment NH3 and NF3 were removed, it was observed that the H and NH peaks gradually decreased. This is because residues originating from N and H-related polymers are formed due to the reaction between NH3 and NF3. After the residues are formed, it can be confirmed that the intensity of the NH and H peaks themselves changes, which is attributed to changes in equipment impedance caused by the residues. It can be understood that the plasma becomes unstable due to the aforementioned residues.

[0075] Figure 7 is a graph showing the residue removal pattern according to the processing time of NF3 plasma. In Figure 7, step ① is an Ar process corresponding to the inert gas activation step (S20) of Figure 2; step ② is an Ar+NH3 process corresponding to the reaction gas activation step (S40) of Figure 2; step ③ is an Ar+NH3+NF3 process corresponding to the etching gas activation step (S60) of Figure 2; and step ④ is a cleaning process using NF3 plasma corresponding to an embodiment of the cleaning step (S110) of Figure 2. The NF3 plasma processing time in step ④ is divided into 0 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, and 60 seconds. The Ar plasma process applies the condition of an Ar flow rate of 3000 sccm, and the NF3 plasma process applies the condition of an NF3 flow rate of 50 sccm. The vertical axis represents the H peak intensity in Optical Emission Spectroscopy (OES).

[0076] Referring to Figure 7, the margin of residue removal time using NF3 plasma was evaluated, and it was confirmed that when the treatment time of NF3 plasma is 30 seconds or longer, the H peak intensity appears to be similar to that of the initial Ar remote plasma. Therefore, it can be seen that 30 seconds or longer is required for residue removal using NF3 remote plasma.

[0077] FIG. 8 is a graph evaluating the residue removal time using hydrogen with high thermal conductivity. The residue removal process using hydrogen with high thermal conductivity corresponds to one embodiment of the cleaning step (S110) of FIG. 2. Specifically, the cleaning step (S110) may include: turning off the power of the remote plasma generator (150) after completing the main etching process, and heating the hydrogen or helium gas by supplying hydrogen or helium gas to the remote plasma generator (150) which has already been heated to a plasma atmosphere; and cleaning the path through which the hydrogen or helium gas flows by supplying the heated hydrogen or helium gas to the reaction space (112) through the gas injection unit (120).

[0078] The graph in the first row of Fig. 8 applies the condition of a hydrogen flow rate of 1000 sccm, the graph in the second row of Fig. 8 applies the condition of a hydrogen flow rate of 750 sccm, and the graph in the third row of Fig. 8 applies the condition of a hydrogen flow rate of 500 sccm. In each row of the graph, the cleaning application times using hydrogen plasma are divided into 0 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, and 60 seconds, respectively.

[0079] Referring to FIG. 8, it can be confirmed that a residue removal effect occurs when hydrogen is flowed at 1000 sccm for 30 seconds. Immediately after the main etching process, the RF power of the remote plasma generator (150) is turned off and hydrogen is flowed. Since the hydrogen gas carries the increased temperature inside the remote plasma generator (150) and flows through the facility, residue removal is possible. As a result of a separate evaluation, it was confirmed that the residue sublimes at approximately 40°C. Since hydrogen (H) has a smaller molecular size compared to argon (Ar), its thermal conductivity is about 10 times higher, making it easy to remove residue by heat. Using gases with small molecular sizes and high thermal conductivity, such as hydrogen (H) and helium (He), allows for a reduction in processing time.

[0080] FIG. 9 is a graph summarizing the results of the residue removal evaluation according to the hydrogen flow of FIG. 8. When the condition of a hydrogen flow rate of 1000 sccm was applied, a decrease in H peak intensity using Optical Emission Spectroscopy (OES) was clearly observed, and it can be confirmed that as the hydrogen flow rate decreases, the effect of reducing H peak intensity gradually diminishes. Meanwhile, when observing the heater power constituting the substrate support (130) while flowing 1000 sccm of hydrogen, it can be confirmed that the heater power decreases for about 32 seconds. The heater constituting the substrate support (130) maintains a constant temperature using the PID (Proportional-Integral-Derivative) method, and a decrease in heater power means that the temperature of the heater rises due to the hydrogen. Therefore, it indicates that the temperature of the remote plasma generator (150) reaches the substrate (S) on the substrate support (130) according to the hydrogen flow.

[0081] FIG. 10 shows the H peak intensity of an Optical Emission Spectroscopy (OES) over time during an argon ignition (Ar ignition) process. The peak intensity shown in FIG. 10 is the result of real-time monitoring analysis in a process in which the inert gas activation step (S20), reaction gas activation step (S40), etching gas activation step (S60), and stabilization step (S120) described with reference to FIG. 2 are sequentially repeated. For example, the argon ignition (Ar ignition) process corresponds to the stabilization step (S120) described with reference to FIG. 2. The stabilization step (S120) may include the step of activating the argon (Ar) gas by supplying argon (Ar) gas to a remote plasma generator (150) and forming a plasma atmosphere.

[0082] Referring to FIG. 10, in the atomic layer etching (ALR) process, the first wafer effect is caused by changes in the temperature and seasoning state of the plasma generation region inside the remote plasma generator (150). The reason the first wafer effect occurs is that when the remote plasma generator (150) is in the idle state, the temperature remains low, so a deviation occurs between the temperature during the main process step and the temperature during the continuous process. To improve the first wafer effect, an argon ignition process is performed in the first cycle of the etching process cycle, in which only argon gas is flowed while the RF power of the remote plasma generator (150) is applied.

[0083] As a result of evaluating the process margin while increasing the time of the argon ignition process, it was confirmed that increasing the time of the argon ignition process can raise the internal temperature of the remote plasma generator (150) and ensure process reproducibility. Specifically, it was confirmed that the 1st Wafer Effect disappears when the time of the argon ignition process is applied to 30 seconds or more.

[0084] Figure 11 is a graph showing the intensity of the NH peak and H peak in Optical Emission Spectroscopy (OES) as a result of performing three consecutive cycles by combining a 30-second argon ignition step and a 30-second hydrogen flow immediately after the main etching process.

[0085] Referring to Fig. 11, when a 30-second argon ignition step is combined with a 30-second hydrogen flow immediately after the main etching process, it can be seen that the 1st Wafer Effect is improved and residues are effectively removed.

[0086] FIG. 12 is a graph showing the particle generation pattern when a substrate processing method according to a comparative example and an embodiment of the present invention is applied. The embodiment of the present invention corresponds to the substrate processing method described above with reference to FIG. 2, and the comparative example of the present invention corresponds to a substrate processing method that does not apply a hydrogen flow process and does not separately perform a stabilization step including an argon ignition step. Referring to FIG. 12, it can be seen that the frequency of particle generation is significantly reduced in the embodiment compared to the comparative example of the present invention.

[0087] FIG. 13 is a graph showing the first wafer effect when a substrate processing method according to a comparative example and an embodiment of the present invention is applied. The embodiment of the present invention corresponds to the substrate processing method described above with reference to FIG. 2, and the comparative example of the present invention corresponds to a substrate processing method that does not apply a hydrogen flow process and does not separately perform a stabilization step including an argon ignition step. With reference to FIG. 13, it can be seen that the first wafer effect is significantly improved in the embodiment compared to the comparative example of the present invention.

[0088] The present invention has been described with reference to the embodiments illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims. Explanation of the symbols

[0089] 100: Substrate processing device 110: Process chamber 120: Gas injection unit 130: Substrate support 140: Plasma power supply 145: Monitoring Department 150: Remote Plasma Generator

Claims

Claim 1 A substrate processing method using a substrate processing apparatus comprising: a process chamber having a reaction space formed therein; a substrate support member coupled to the process chamber; a gas injection unit coupled to the process chamber so as to face the substrate support member and for injecting process gas into the reaction space; a remote plasma generator spaced apart from the process chamber and disposed on a gas supply line communicating with the gas injection unit, capable of forming a plasma atmosphere to activate the process gas; and a monitoring unit for real-time monitoring of the state of the plasma generated from the remote plasma generator, wherein the cleaning step of cleaning the path through which the process gas flows according to the real-time monitoring result by the monitoring unit is characterized by proceeding with the substrate processing process when the real-time monitoring result by the monitoring unit is within a preset value, and cleaning the path through which the process gas flows when the real-time monitoring result deviates from the preset value, wherein the real-time monitoring result by the monitoring unit is a step of activating the NH3 gas and NF3 gas by supplying NH3 gas and NF3 gas to the remote plasma generator and forming a plasma atmosphere; A substrate processing method comprising: a step of supplying the activated NH3 gas and NF3 gas to the reaction space through the gas injection unit; a step of supplying only argon (Ar) gas to the remote plasma generator and forming a plasma atmosphere to activate the argon (Ar) gas; and a step of supplying the activated argon (Ar) gas to the reaction space through the gas injection unit, wherein the real-time monitoring result by the monitoring unit includes the intensity of the emission peak of an H radical or NH radical analyzed in real-time by an optical emission spectroscopy (OES) of the plasma state. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A substrate processing method according to claim 1, wherein the cleaning step comprises: a step of supplying hydrogen or helium gas to the remote plasma generator and forming a plasma atmosphere to activate the hydrogen or helium gas; and a step of cleaning the path through which the hydrogen or helium gas flows by supplying the activated hydrogen or helium gas to the reaction space through the gas injection unit. Claim 7 A substrate processing method according to claim 1, wherein the cleaning step comprises: a step of heating the hydrogen or helium gas by supplying hydrogen or helium gas to the remote plasma generator heated to a plasma atmosphere; and a step of cleaning the path through which the hydrogen or helium gas flows by supplying the heated hydrogen or helium gas to the reaction space through the gas injection unit. Claim 8 A substrate processing method according to claim 1, wherein the cleaning step comprises: a step of supplying a gas containing a halogen element to a remote plasma generator and forming a plasma atmosphere to activate the gas containing the halogen element; and a step of cleaning the path through which the gas containing the halogen element flows by supplying the activated gas containing the halogen element to the reaction space through the gas injection unit. Claim 9 A substrate treatment method according to claim 8, wherein the gas containing the halogen element comprises either NF3 or F2. Claim 10 A substrate processing method according to claim 8, characterized in that the cleaning step is performed before the step of placing the substrate on the substrate support. Claim 11 A substrate processing method according to claim 1, wherein a stabilization step for stabilizing a substrate processing device is further performed according to the real-time monitoring result by the monitoring unit, the stabilization step comprises the step of supplying argon (Ar) gas to the remote plasma generator and forming a plasma atmosphere to activate the argon (Ar) gas. Claim 12 A substrate processing method according to claim 11, characterized in that the step of activating the argon (Ar) gas is performed for 30 seconds or more.

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