Plasma processing apparatus and plasma state detection method

Abstract

To provide a plasma processing apparatus and a plasma state detection method for detecting a plasma state.SOLUTION: A plasma processing apparatus comprising: a processing container having an inner space; a substrate support unit provided in the inner space of the processing container; a gas supply unit configured to supply a processing gas into the inner space of the processing container; a plasma generation unit configured to generate plasma in the inner space of the processing container; a vibration detection sensor provided outside the inner space of the processing container; and a control unit, wherein the control unit detects a state of the plasma based on vibration detected by the vibration detection sensor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a plasma processing apparatus and a plasma state detection method. [Background technology]

[0002] Patent Document 1 discloses a plasma processing apparatus comprising a chamber for accommodating a substrate, an electrode disposed in the chamber for applying high frequency power into the chamber, and a pipe for introducing a processing gas into the chamber, the plasma processing apparatus further comprising a potential fluctuation detection means for detecting potential fluctuations, an ultrasonic wave detection means for detecting ultrasonic waves, and an abnormal discharge determination means for determining that an abnormal discharge has occurred when the potential fluctuation and the ultrasonic waves are detected.

[0003] Patent Document 2 discloses an anomaly detection system that detects anomalies occurring in a processing device, comprising: a plurality of ultrasonic sensors for detecting acoustic emissions generated in the processing device; a distribution unit that distributes each output signal of the plurality of ultrasonic sensors into a first signal and a second signal; a trigger generation unit that samples the first signal at a first frequency and generates a trigger signal when a predetermined feature is detected; a trigger generation time determination unit that receives the trigger signal and determines the trigger generation time; a data creation unit that creates sampling data by sampling the second signal at a second frequency that is higher than the first frequency; and a data processing unit that analyzes an anomaly that has occurred in the processing device by performing waveform analysis on data of the sampling data that corresponds to a certain period based on the trigger generation time determined by the trigger generation time determination unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-128304 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-014608 Summary of the Invention [Problem to be solved by the invention]

[0005] In one aspect, the present disclosure provides a plasma processing apparatus and a plasma state detection method for detecting a state of plasma. [Means for solving the problem]

[0006] In order to solve the above problem, according to one aspect, a plasma processing apparatus is provided, comprising: a processing vessel having an internal space; a substrate support unit provided within the internal space of the processing vessel; a gas supply unit that supplies a processing gas into the internal space of the processing vessel; a plasma generation unit that generates plasma within the internal space of the processing vessel; a vibration detection sensor provided outside the internal space of the processing vessel; and a control unit, wherein the control unit detects the state of the plasma based on vibrations detected by the vibration detection sensor. [Effects of the Invention]

[0007] According to one aspect, it is possible to provide a plasma processing apparatus and a reaction tube wall protection member that suppress wear of a reaction tube. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an example of a vertical cross-sectional side view showing a plasma processing apparatus according to an embodiment; [Figure 2] 1 is a cross-sectional plan view illustrating an example of a plasma processing apparatus according to an embodiment; [Figure 3] FIG. 2 is a block diagram illustrating an example of a functional configuration of a control unit. [Figure 4] 1 is an example of a flowchart illustrating a plasma state detection method. [Figure 5] 6 is a graph showing an example of vibration detection results and analysis results. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0010] [Plasma processing equipment] A plasma processing apparatus (film forming apparatus) 1 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. FIG. 1 is an example of a longitudinal side view showing the plasma processing apparatus 1 according to an embodiment. FIG. 2 is an example of a cross-sectional plan view showing the plasma processing apparatus 1 according to an embodiment. The plasma processing apparatus 1 is a substrate processing apparatus that generates plasma in a vacuum chamber 11 and performs substrate processing (plasma processing) on ​​a wafer W, which is an example of a substrate.

[0011] In the following description, the plasma processing apparatus 1 will be described as an example of a film forming apparatus that forms a film on a wafer W by atomic layer deposition (ALD). The plasma processing apparatus (film forming apparatus) 1 forms a film on the wafer W by repeating the following steps: supplying a source gas to the wafer W to adsorb the source gas onto the wafer W; supplying a reactive gas to the wafer W to react with the source gas adsorbed on the wafer W to form a molecular layer; and generating plasma of a modifying gas and exposing the wafer W to the generated plasma to modify the molecular layer formed on the wafer W. In the following description, a silicon oxide film (SiO) is formed on the wafer W using BTBAS (bistertiarybutylaminosilane) gas, a process gas containing silicon (Si), as the source gas; ozone (O) gas, an oxidizing gas (process gas containing oxygen (O)), as the reactive gas; and a mixed gas of argon (Ar) gas and oxygen (O) gas as the modifying gas (plasma generating gas).

[0012] The plasma processing apparatus 1 includes a generally circular, flat vacuum chamber 11 and a disk-shaped, horizontal rotary table (substrate support unit) 2 provided within the vacuum chamber 11. The vacuum chamber 11 includes a chamber top plate 12 and a chamber body 13. The chamber body 13 is open at the top and forms the side walls and bottom of the vacuum chamber 11. The chamber top plate 12 covers the opening formed at the top of the chamber body 13 and forms the ceiling wall of the vacuum chamber 11.

[0013] A central shaft 21 extending vertically downward from the center of the turntable 2 is provided at the center of the vacuum vessel 11. The central shaft 21 is connected to a revolution rotation drive unit 22 that is provided to cover an opening 14 formed in the bottom of the vessel body 13. The turntable 2 is supported within the vacuum vessel 11 via the central shaft 21 and the revolution rotation drive unit 22. The turntable 2 rotates clockwise or counterclockwise in a plan view of the plasma processing apparatus 1. The revolution rotation drive unit 22 is, for example, an electric actuator such as a motor. A gas supply pipe 15 discharges N2 (nitrogen) gas into the gap between the central shaft 21 and the vessel body 13, thereby preventing the source gas and oxidizing gas from flowing from the front surface to the back surface of the turntable 2.

[0014] Additionally, on the underside of the vessel top plate 12 of the vacuum vessel 11, there are formed a central region forming portion C that is circular in plan view and protrudes so as to face the center of the turntable 2, and two convex portions 17 (see FIG. 2) that spread out from the central region forming portion C toward the outside of the turntable 2. The two convex portions 17 have a generally fan-shaped planar shape with their tops cut in an arc shape.

[0015] The central region forming portion C and the convex portion 17 form a ceiling surface that is lower than the outer regions. The gap between the central region forming portion C and the center of the turntable 2 forms a flow path 18 for N2 gas (see FIG. 1). During processing of the wafer W, N2 gas is supplied to the flow path 18 from a gas supply pipe connected to the container top plate 12 and flows from the flow path 18 toward the entire outer periphery of the turntable 2. This N2 gas prevents the source gas and the oxidizing gas from coming into contact with each other at the center of the turntable 2.

[0016] A flat ring-shaped recess 31 is formed in the bottom of the container body 13 below the turntable 2 and along the periphery of the turntable 2. A ring-shaped slit 32 is formed in the bottom surface of the recess 31 along the circumferential direction of the recess 31, and the slit 32 is formed to penetrate the bottom of the container body 13 in the thickness direction. Furthermore, seven ring-shaped heaters 33 for heating the wafers W placed on the turntable 2 are arranged on the bottom surface of the recess 31.

[0017] The heaters 33 are arranged along concentric circles centered on the rotation center of the turntable 2, with four of the seven heaters 33 located inside the slits 32 and the other three located outside the slits 32. A shield 34 is provided to cover the heaters 33 and close the upper side of the recess 31. A ring-shaped slit 37 is formed in the shield 34 so as to overlap the slit 32, and support columns 41 pass through the slits 32 and 37. Exhaust ports 35 and 36 for evacuating the inside of the vacuum vessel 11 are open at the bottom of the vessel body 13, outside the recess 31 (see FIGS. 1 and 2). An exhaust mechanism (not shown), composed of a vacuum pump or the like, is connected to the exhaust ports 35 and 36.

[0018] As shown in Fig. 2, five circular recesses 23 are formed on the surface of the turntable 2 along the direction of rotation of the turntable 2, and a circular wafer holder (substrate support portion) 24 is provided in each recess 23. As shown in Fig. 1, a recess 25 is formed on the surface of the wafer holder 24, and a wafer W is stored horizontally in the recess 25. Therefore, the bottom surface of the recess 25 forms a mounting surface on which the wafer W is placed. In this example, the height of the sidewall of the recess 25 is set to the same as the thickness of the wafer W, for example, 1 mm.

[0019] For example, three support columns 41 extend vertically downward from positions spaced apart in the circumferential direction on the back surface of the turntable 2. As shown in FIG. 1, each support column 41 penetrates the bottom of the container body 13 via slits 32 and 37 and is connected to a support ring 42, which is a connection portion provided below the container body 13. The support ring 42 is formed along the rotation direction of the turntable 2 and is provided horizontally so as to be suspended from the container body 13 by the support columns 41, and rotates together with the turntable 2.

[0020] Furthermore, a rotation shaft 26, which is a rotation shaft for rotation, extends vertically downward from the lower center of wafer holder 24. The lower end of rotation shaft 26 penetrates turntable 2, penetrates the bottom of container body 13 via slit 32, and further penetrates support ring 42 and magnetic seal unit 20 provided below support ring 42, to be connected to rotation drive unit 27 for rotation. Magnetic seal unit 20 is composed of a bearing for rotatably supporting rotation shaft 26 with respect to support ring 42, and a magnetic seal (magnetic fluid seal) for sealing the gap around rotation shaft 26.

[0021] The magnetic seal is provided to prevent particles generated from the bearing, such as lubricating oil used in the bearing, from diffusing into the vacuum atmosphere outside the magnetic seal unit 20. Furthermore, since the rotating shaft 26 is supported by the bearing, the wafer holder 24 is slightly suspended above, for example, the turntable 2. Furthermore, the rotation drive unit 27 is provided below the support ring 42 so as to be supported by the support ring 42 via the magnetic seal unit 20, and rotates the rotating shaft 26 about its axis. The rotation drive unit 27 is, for example, an electric actuator such as a motor. In the plasma processing apparatus 1, the wafer W revolves as the turntable 2 rotates, and the wafer holder 24 rotates in parallel with the rotation of the turntable 2, causing the wafer W to rotate.

[0022] 1, the shield ring 44 is provided so as to close the slit 32 in the container body 13 from the lower side of the container body 13, and is configured to rotate together with the turntable 2. Therefore, the rotating shaft 26 and the support column 41 are provided so as to pass through the shield ring 44. The shield ring 44 serves as a heat shield to prevent the rotation drive unit 27 from being exposed to the gases and from being excessively heated.

[0023] A lower wall 45 is formed below the vessel body 13. The lower wall 45 is concave in cross section and surrounds the support ring 42, the rotational drive units 27, and the shield ring 44. The lower wall 45 is ring-shaped and extends in the direction of rotation of the turntable 2. Five charging mechanisms 46 (only one of which is shown in FIG. 1 ) are provided at the bottom of the lower wall 45, spaced apart from each other in the circumferential direction. When no wafers W are being processed, the turntable 2 is stationary so that the rotational drive units 27 are positioned directly below the charging mechanisms 46. Each of the rotational drive units 27 can be charged by wireless power supply from the charging mechanisms 46. The gas supply path 47 opens into the space surrounded by the lower wall 45. For example, during processing of the wafers W, a gas nozzle 48 supplies N2 gas through the gas supply path 47 into the space surrounded by the lower wall 45 to purge the space. For example, this space communicates with an exhaust path that connects the exhaust ports 35, 36 with the above-mentioned exhaust mechanism (not shown), and even if particles are generated in this space, the particles are purged and removed by N2 gas.

[0024] A transfer port 38 for the wafer W and a gate valve 39 for opening and closing the transfer port 38 are provided in the side wall of the vessel body 13 (see FIG. 2), and the wafer W is transferred between the transfer device that enters the vacuum vessel 11 through the transfer port 38 and the recessed portion 25. Specifically, through holes are formed in the bottom of the recessed portion 25, the bottom of the vessel body 13, and the turntable 2 at corresponding positions, and the tips of pins move up and down through each through hole. The wafer W is transferred via these pins. The pins and the through holes through which the pins pass are not shown in the figure.

[0025] 2, a raw material gas nozzle 51, a separation gas nozzle 52, an oxidizing gas nozzle 53, a plasma generation gas nozzle 54, and a separation gas nozzle 55 are arranged on the turntable 2 in this order at intervals in the rotation direction of the turntable 2. Each of the gas nozzles 51 to 55 is formed in a rod shape extending horizontally along the diameter of the turntable 2 from the side wall toward the center of the vacuum chamber 11, and discharges gas downward from a number of discharge ports 56 formed along the diameter. Each of the gas nozzles (gas supply units) 51 to 55 is an example of a gas supply unit that supplies gas into the vacuum chamber 11.

[0026] The raw material gas nozzle 51, which constitutes the process gas supply mechanism, discharges the above-mentioned BTBAS (bisterial butyl amino silane) gas. The nozzle cover 57 covers the raw material gas nozzle 51 and is formed in a fan shape that spreads from the raw material gas nozzle 51 toward both the upstream and downstream sides in the rotation direction of the turntable 2. The nozzle cover 57 increases the concentration of BTBAS gas below it, thereby enhancing the adsorption of the BTBAS gas to the wafer W. The oxidizing gas nozzle 53 discharges the above-mentioned ozone (O3) gas. The separation gas nozzles 52 and 55 are gas nozzles that discharge N2 gas and are arranged so as to divide the fan-shaped convex portion 17 of the container top plate 12 in the circumferential direction. The plasma generation gas nozzle 54 discharges a plasma generation gas, for example, a mixture of argon (Ar) gas and oxygen (O2) gas.

[0027] A fan-shaped opening 19 is provided in vessel top plate 12 along the rotation direction of turntable 2, and a cup-shaped antenna top plate (top plate member) 61 made of a dielectric material such as quartz and corresponding to the shape of opening 19 is provided to close this opening 19 (see FIGS. 1 and 2). This antenna top plate 61 is provided between oxidizing gas nozzle 53 and convex portion 17 when viewed in the rotation direction of turntable 2. In FIG. 2, the position where antenna top plate 61 is provided is indicated by a dashed line.

[0028] A protrusion 62 is provided along the periphery of the underside of the antenna top plate 61. A plasma generation region is formed between the antenna top plate 61 and the turntable 2 (wafer holder 24) in the area surrounded by the protrusion 62. The tip of the plasma generation gas nozzle 54 penetrates the protrusion 62 from the outer periphery of the turntable 2 so that gas can be discharged into the plasma generation region surrounded by the protrusion 62. The protrusion 62 prevents N2 gas, ozone (O3) gas, and BTBAS gas from entering below the antenna top plate 61, and serves to prevent a decrease in the concentration of the plasma generation gas.

[0029] A recess is formed on the upper side of the antenna top plate 61, and a box-shaped Faraday shield 63 with an opening at the top is disposed in this recess. An antenna 65 is mounted on the bottom surface of the Faraday shield 63 via an insulating plate member 64. The antenna 65 is configured by winding a metal wire in a coil shape around a vertical axis. A high-frequency power supply 66 is connected to the antenna 65. A slit 67 is formed on the bottom surface of the Faraday shield 63 to prevent the electric field component of the electromagnetic field generated in the antenna 65 from traveling downward when high-frequency power is applied to the antenna 65 and to direct the magnetic field component downward (see FIG. 2). The slits 67 extend in a direction perpendicular to (intersecting) the winding direction of the antenna 65, and multiple slits 67 are formed along the winding direction of the antenna 65. With this configuration, the antenna 65 is coupled to the vacuum chamber 11 and configured to generate plasma within the vacuum chamber 11. When the high-frequency power supply 66 is turned on and high-frequency power is applied to the antenna 65, the plasma-generating gas supplied below the antenna top plate 61 can be converted into plasma. The antenna 65 and the high frequency power supply 66 constitute a plasma generating unit that generates plasma within the vacuum vessel 11 .

[0030] The antenna top plate 61 has a protrusion 62 and a portion inside the protrusion 62 inserted into the opening 19 of the container top plate 12. The antenna top plate 61 has a flange portion that extends horizontally outward beyond the protrusion 62. The lower peripheral edge of the flange portion is engaged with the container top plate 12, and the upper peripheral edge of the flange portion is pressed and fixed by a press ring 68. That is, the antenna top plate 61 is held in place by the flange portion of the antenna top plate 61 being sandwiched between the container top plate 12 and the press ring 68. A seal member 69a is disposed and sandwiched between the lower peripheral edge of the flange portion of the antenna top plate 61 and the container top plate 12. A seal member 69b is disposed and sandwiched between the upper peripheral edge of the flange portion of the antenna top plate 61 and the press ring 68. The press ring 68 is fixed to the container top plate 12 by fastening members 69c (not shown), such as bolts.

[0031] The plasma processing apparatus 1 is also provided with a vibration detection sensor 70 that detects high-frequency vibrations of the plasma processing apparatus 1. As the vibration detection sensor 70, a wide range of vibration sensors can be used, such as an AE (Acoustic Emission) sensor, a piezoelectric element, or a SAW (Surface Acoustic Wave) sensor.

[0032] In particular, the vibration detection sensor 70 is preferably a vibration detection sensor that can detect vibrations over a wide frequency band (for example, a frequency band of 0.01 Hz to 1000 kHz) and uses a sheet-shaped piezoelectric element. This provides high sensitivity and a high S / N ratio, and can suitably detect minute vibration phenomena over a predetermined high frequency band (for example, a frequency band around 500 kHz, specifically a frequency band of 450 kHz to 550 kHz). Furthermore, by using a vibration detection sensor 70 that can detect vibrations over a wide frequency band, transient phenomena that occur during plasma ignition can be detected.

[0033] The vibration detection sensor 70 is preferably provided on a member close to the plasma generation region. Specifically, the vibration detection sensor 70 is provided on a pressing ring 68 that presses down on the antenna top plate 61 that forms the top wall of the plasma generation region. This allows the vibration detection sensor 70 to detect high-frequency vibrations of the antenna top plate 61. Note that the vibration detection sensor 70 may also be configured to be directly attached to the antenna top plate 61.

[0034] 1 and 2 has been described as having one plasma generation region, but the present invention is not limited to this configuration. The plasma processing apparatus 1 may be configured to have multiple plasma generation regions. In this case, a vibration detection sensor 70 may be provided on each of the pressing rings 68 that press the antenna top plate 61 corresponding to each plasma generation region.

[0035] On the turntable 2, the area below the nozzle cover 57 of the source gas nozzle 51 is defined as an adsorption region R1 where the source gas, BTBAS gas, is adsorbed, and the area below the oxidizing gas nozzle 53 is defined as an oxidation region R2 where the BTBAS gas is oxidized by ozone (O3) gas. The area below the antenna top plate 61 is defined as a plasma formation region R3 where the SiO2 film is modified by plasma. The areas below the convex portion 17 are separated into adsorption region R1 and oxidation region R2 by N2 gas discharged from separation gas nozzles 52 and 55, forming separation regions D and D to prevent the source gas and oxidizing gas from mixing.

[0036] The exhaust port 35 opens to the outside between the adsorption region R1 and the adjacent separation region D downstream of the adsorption region R1 in the rotation direction, and exhausts excess BTBAS gas. The exhaust port 36 opens to the outside near the boundary between the plasma formation region R3 and the adjacent separation region D downstream of the plasma formation region R3 in the rotation direction, and exhausts excess O gas and plasma generating gas. The exhaust ports 35 and 36 also exhaust N gas supplied from each separation region D, the gas supply pipe 15 below the turntable 2, and the central region formation section C of the turntable 2.

[0037] The plasma processing apparatus 1 is provided with a control unit 100 that controls the overall operation of the apparatus (see FIG. 1). The control unit 100 is configured, for example, by a computer. The control unit 100 stores a program for executing a substrate processing method. The program sends control signals to each component of the plasma processing apparatus 1 to control the operation of each component. For example, the control signals control the gas flow rate supplied from each gas nozzle 51-55, the temperature of the wafer W controlled by the heater 33, the flow rate of N2 gas supplied from the gas supply pipe 15 and the central region forming unit C, the rotation speed of the turntable 2, and the rotation speed of the wafer holder 24. The recipe (program) also sets process conditions for each step of the substrate processing method. The recipe and other programs are installed into the control unit 100 from a storage medium such as a hard disk, a compact disk, a magneto-optical disk, a memory card, or a flexible disk.

[0038] In this plasma processing apparatus 1, the rotation of the turntable 2 causes the wafer W to revolve and repeatedly pass through the adsorption region R1, separation region D, oxidation region R2, plasma generation region R3, and separation region D in this order, thereby performing a film formation process by ALD. As described above, the rotation of the turntable 2 is parallel to the rotation of the wafer W, and the rotation of the wafer holder 24 is performed by the rotation of the wafer holder 24. However, the rotation of the turntable 2 and the rotation of the wafer holder 24 may be synchronized. Specifically, the turntable 2 may rotate once from a state in which the wafer W is oriented in a first orientation at a predetermined position in the vacuum chamber 11, and when the turntable 2 rotates once again at the predetermined position, the wafer W may rotate at a rotation speed (rotation speed) such that the wafer W is oriented in a second orientation different from the first orientation. The rotation speed (unit: rpm) of the wafer W is set by the control unit 100 based on parameters set by the operator on a specific setting screen, as described below.

[0039] [Plasma state detection method] Next, the plasma state detection method will be described with reference to Figures 3 and 4. Figure 3 is an example of a block diagram showing the functional configuration of the control unit 100.

[0040] The control unit 100 includes a vibration acquisition unit 110, an analysis unit 120, and a plasma state determination unit .

[0041] The vibration acquisition unit 110 acquires a detection signal from the vibration detection sensor 70 .

[0042] The analysis unit 120 analyzes the vibrations acquired by the vibration acquisition unit 110. Here, the analysis unit 120 performs frequency analysis of the vibrations by, for example, Fourier analysis.

[0043] The plasma state determination unit 130 determines the plasma state based on the analysis results of the analysis unit 120. Specifically, the plasma state determination unit 130 determines at least one of plasma ignition, ignition delay, and misfire based on the analysis results of the analysis unit 120.

[0044] FIG. 4 is an example of a flowchart illustrating a plasma state detection method.

[0045] In step S101, the control unit 100 controls the high frequency power to be applied to the antenna 65. Here, the control unit 100 controls the high frequency power supply 66 to control the high frequency power to be applied to the antenna 65. Note that the control of the high frequency power to be applied to the antenna 65 includes starting and ending the application of the high frequency power to the antenna 65.

[0046] In step S102, vibrations of the retaining ring 68 (antenna top plate 61) are detected. Here, the vibration detection sensor 70 detects vibrations of the retaining ring 68 (antenna top plate 61) and outputs a detection signal to the vibration acquisition unit 110. Then, the vibration acquisition unit 110 acquires the detection signal from the vibration detection sensor 70.

[0047] In step S103, the plasma state is detected. The control unit 100 determines the plasma state (at least one of plasma ignition, ignition delay, and misfire) based on the vibration of the retaining ring 68 (antenna top plate 61) acquired by the vibration acquisition unit 110. Specifically, the analysis unit 120 performs frequency analysis of the vibration acquired by the vibration acquisition unit 110, for example, by Fourier analysis. The plasma state determination unit 130 then determines that the plasma is ignited if the spectral intensity in a predetermined high-frequency band R (see FIGS. 5(c) and 5(d) described below; for example, a frequency band around 500 kHz, specifically a frequency band of 450 kHz to 550 kHz) exceeds a predetermined threshold. On the other hand, the plasma state determination unit 130 determines that the plasma is misfired if the spectral intensity in the predetermined high-frequency band R does not exceed the predetermined threshold.

[0048] FIG. 5 is a graph showing an example of the vibration detection results and analysis results.

[0049] 5(a) shows the vibration (original waveform) of the retaining ring 68 (antenna top plate 61) detected by the vibration detection sensor 70 and acquired by the vibration acquisition unit 110. The horizontal axis represents time, and the vertical axis represents the amplitude of the vibration. The timing at which the application of high-frequency power to the antenna 65 starts (Plasma On) and ends (Plasma Off) is indicated by white arrows.

[0050] As shown in FIG. 5(a), the amplitude of the oscillation appears before plasma generation (before Plasma On), during plasma generation (between Plasma On and Plasma Off), and after plasma generation (after Plasma Off).

[0051] FIG. 5(b) is a graph showing the frequencies at which the spectral intensity peaks when the vibration is frequency-analyzed using Fourier analysis. The horizontal axis represents time, and the vertical axis represents the frequency at which the spectral intensity peaks. Here, the analysis unit 120 performs frequency analysis on the vibration (see FIG. 5(a)) using Fourier analysis, and calculates the spectral intensity for each frequency. FIG. 5(b) shows a graph plotting the frequencies at which the spectral intensity peaks (maximums).

[0052] Figure 5(c) is a graph showing the relationship between the vibration frequency and the spectral intensity when the plasma misfires (A-A' or C-C'). Figure 5(d) is a graph showing the relationship between the vibration frequency and the spectral intensity when the plasma ignites (B-B'). In Figures 5(c) and 5(d), the vertical axis shows the vibration frequency, and the horizontal axis shows the spectral intensity corresponding to the vibration frequency.

[0053] As shown in FIGS. 5(b) and 5(c), no peak appears in the spectral intensity before plasma generation (before Plasma On).

[0054] As shown in FIG. 5(b), when the application of high-frequency power to the antenna 65 starts (Plasma On), the frequency at which the spectral intensity peaks changes transiently. That is, when the application of high-frequency power to the antenna 65 starts (Plasma On), the frequency at which the spectral intensity peaks increases. By using a vibration detection sensor 70 capable of detecting a wide band, it is possible to detect transient changes in vibration, as shown in FIG. 5(b). In other words, it is possible to detect transient changes in the plasma state.

[0055] As shown in FIGS. 5(b) and 5(d), after plasma is ignited, if the plasma state becomes stable, a spectral intensity peak appears in a predetermined high-frequency band R. That is, the plasma state determination unit 130 can determine whether plasma has been ignited based on whether a spectral intensity peak appears in the predetermined high-frequency band R. In other words, the plasma state determination unit 130 can determine that plasma has been ignited if the spectral intensity in the predetermined high-frequency band R is equal to or greater than a predetermined threshold. Furthermore, if the time difference between the start of application of high-frequency power to the antenna 65 (Plasma On) and the timing at which it is determined that plasma has been ignited exceeds a predetermined threshold time, it can determine that an ignition delay has occurred.

[0056] 5(b) and 5(c), when the application of high-frequency power to antenna 65 is stopped (Plasma Off), no peak appears in the spectral intensity. In other words, the plasma state determination unit 130 can determine that the plasma has extinguished when the spectral intensity in the predetermined high-frequency band R is less than a predetermined threshold.

[0057] In this way, the analysis unit 120 calculates the spectral intensity for each frequency from the amplitude of the detected vibration (see FIG. 5(a)) by analyzing (e.g., Fourier analysis) the vibration detected by the vibration detection sensor 70. Then, the plasma state determination unit 130 can detect a transient change in the plasma state based on the transient change in the frequency at which the spectral intensity peaks (see FIG. 5(b)).

[0058] Furthermore, if the spectral intensity in the predetermined high frequency band R is equal to or greater than a predetermined threshold (see FIG. 5(d)), the plasma state determination unit 130 determines that the plasma has ignited. On the other hand, if the spectral intensity in the predetermined high frequency band R is not equal to or greater than a predetermined threshold (see FIG. 5(c)), the plasma state determination unit 130 determines that the plasma has misfired. Even in the case of unexpected plasma misfire, the plasma misfire can be detected by determining that the spectral intensity in the predetermined high frequency band R is not equal to or greater than a predetermined threshold.

[0059] The predetermined high frequency band R may be a frequency band including the natural frequency of the antenna top plate 61 and / or the retaining ring 68, which vibrate due to plasma generation. The peak value and frequency bandwidth of the detected spectrum vary depending on the natural frequency and rigidity of the object to which the sensor is attached.

[0060] Also, there is known a plasma processing apparatus in which a sapphire glass window is provided on the sidewall of the vessel body, and an optical detector provided outside the vessel body detects the plasma emission in the vacuum vessel through the sapphire glass window to detect the state of the plasma. Compared to such plasma processing apparatuses, the plasma processing apparatus 1 according to this embodiment does not require an expensive sapphire glass window, thereby reducing the cost of the apparatus. Furthermore, no window is required on the sidewall of the vessel body, thereby preventing leakage.

[0061] Furthermore, by providing a vibration detection sensor 70 outside the processing space (internal space of the vacuum vessel 11) of the plasma processing apparatus 1 (for example, on the upper surface of the retaining ring 68), the state of the plasma can be detected.

[0062] 1 and 2, the plasma processing apparatus 1 that detects the state of plasma based on vibrations detected by the vibration detection sensor 70 has been described as an example, but is not limited to this configuration. It may be applied to a configuration in which the state of plasma is detected based on vibrations detected by a vibration detection sensor in an inductively coupled plasma (ICP) apparatus, a capacitively coupled plasma (CCP) apparatus, or a microwave plasma (MP) apparatus. Furthermore, while the plasma processing apparatus 1 has been described as a film deposition apparatus, it is not limited to this and may also be applied to a plasma etching apparatus.

[0063] The present invention is not limited to the configurations described in the above embodiments, but may be combined with other elements, etc. These aspects can be changed without departing from the spirit of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0064] W wafer 1. Plasma processing equipment (film forming equipment) 2 Rotating table (substrate support part) 11 Vacuum container 12 Container top 13 Container body 19 Opening 24 Wafer holder (substrate support part) 51~55 Gas nozzle (gas supply part) 61 Antenna top plate (top plate material) 65 Antenna (Plasma Generation Unit) 66 High frequency power supply (plasma generating part) 68 Retaining ring 69a Sealing member 69b sealing member 69c Fastening members 70 Vibration detection sensor 100 control section 110 Vibration acquisition section 120 Analysis Department 130 Plasma state determination unit R Predetermined high frequency band

Claims

1. a processing vessel having an internal space; a substrate support provided in the internal space of the processing vessel; a gas supply unit that supplies a processing gas into the internal space of the processing vessel; a plasma generating unit that generates plasma in the internal space of the processing vessel; a vibration detection sensor provided outside the internal space of the processing vessel; a control unit, The control unit detecting a state of the plasma based on the vibration detected by the vibration detection sensor; Plasma processing equipment.

2. The control unit analyzing the vibration detected by the vibration detection sensor to calculate a spectrum intensity corresponding to a frequency; detecting a state of the plasma based on a transient change in the peak of the spectral intensity; The plasma processing apparatus according to claim 1 .

3. The control unit analyzing the vibration detected by the vibration detection sensor to calculate a spectrum intensity corresponding to a frequency; detecting at least one of ignition, ignition delay, and misfire of the plasma based on the spectral intensity in a predetermined frequency band; The plasma processing apparatus according to claim 1 .

4. The processing vessel comprises: A container body that is open at the top; a container top plate that closes the opening; a top plate member disposed at an opening of the vessel top plate and disposed above a plasma generation region; a press ring for fixing the top plate member to the container top plate, The vibration detection sensor provided on the top plate member or the retaining ring, The plasma processing apparatus according to claim 3 .

5. the predetermined frequency band is a band including a natural frequency of the top plate member or the retaining ring; The plasma processing apparatus according to claim 4 .

6. A plasma state detection method for a plasma processing apparatus including a processing vessel having an internal space, a substrate support unit provided in the internal space of the processing vessel, a gas supply unit that supplies a processing gas into the internal space of the processing vessel, a plasma generation unit that generates plasma in the internal space of the processing vessel, and a vibration detection sensor provided outside the internal space of the processing vessel, comprising: detecting a state of the plasma based on the vibration detected by the vibration detection sensor; Plasma state detection method.

7. analyzing the vibration detected by the vibration detection sensor to calculate a spectrum intensity corresponding to a frequency; detecting a state of the plasma based on a transient change in the peak of the spectral intensity; The plasma state detection method according to claim 6.

8. analyzing the vibration detected by the vibration detection sensor to calculate a spectrum intensity corresponding to a frequency; detecting ignition or misfire of the plasma based on the spectral intensity in a predetermined frequency band; The plasma state detection method according to claim 6.

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