Method for controlling plasma measurement system and plasma measurement system

Abstract

To provide a method for controlling a plasma measurement system and a plasma measurement system for desirably cleaning a probe device.SOLUTION: A method for controlling a plasma measurement system includes: a probe device provided in a plasma processing apparatus; and a measurement circuit for outputting an AC voltage for plasma measurement to the probe device and measuring the state of plasma generated in the plasma processing apparatus. During cleaning of the plasma processing apparatus, the absolute value of a voltage applied to the probe device is larger than the absolute value of the AC voltage for plasma measurement.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a method for controlling a plasma measurement system and a plasma measurement system. [Background technology]

[0002] Patent Document 1 discloses a plasma probe device having an antenna unit attached to an opening formed in the wall of a processing vessel or in a mounting table via a sealing member that seals between the vacuum space and the atmospheric space, an electrode connected to the antenna unit, and a dielectric support unit formed from a dielectric and supporting the antenna unit from the periphery, wherein the opposing surfaces of the antenna unit and the wall or mounting table are separated by a predetermined width, and the surface of the antenna unit exposed from the opening is recessed compared to the surface of the wall or mounting table on the plasma generation space side in which the opening is formed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-46787 Summary of the Invention [Problem to be solved by the invention]

[0004] In one aspect, the present disclosure provides a plasma measurement system and a method for controlling the plasma measurement system that suitably cleans a probe device. [Means for solving the problem]

[0005] In order to solve the above problem, according to one aspect, there is provided a control method for a plasma measurement system having a probe device provided in a plasma processing apparatus and a measurement circuit that outputs an AC voltage for plasma measurement to the probe device and measures the state of plasma generated in the plasma processing apparatus, wherein the absolute value of the voltage applied to the probe device when cleaning the plasma processing apparatus is greater than the absolute value of the AC voltage for plasma measurement. [Effects of the Invention]

[0006] According to one aspect, it is possible to provide a plasma measurement system and a method for controlling the plasma measurement system that suitably cleans a probe device. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view showing an example of a plasma processing apparatus according to an embodiment; [Figure 2] FIG. 2 is a diagram showing an example of a cross section AA of FIG. [Figure 3] FIG. 2 is a diagram showing an example of the functional configuration of a measurement system and a control device according to an embodiment. [Figure 4] 10 is a flowchart showing an example of a method for controlling a plasma processing apparatus. [Figure 5] An example of a circuit model for a measurement system. [Figure 6] 10 is an example of a graph showing an estimated plasma electron temperature. [Figure 7] 10A and 10B are diagrams illustrating an example of a schematic diagram showing supply of a processing gas, supply of a cleaning gas, voltage supplied to a probe device, and changes in film thickness in the first substrate processing method. [Figure 8] FIG. 2 is a diagram showing an example of a circuit configuration for applying a voltage to a probe device. [Figure 9] FIG. 10 is a diagram showing another example of a circuit configuration for applying a voltage to a probe device. [Figure 10] FIG. 4 is a diagram showing an example of a voltage applied to a probe device. [Figure 11]FIG. 10 is a diagram illustrating an example of a schematic diagram showing supply of a processing gas, supply of a cleaning gas, voltage supplied to a probe device, and changes in film thickness in a second substrate processing method. [Figure 12] 10A and 10B are diagrams illustrating an example of a schematic diagram showing supply of a processing gas, supply of a cleaning gas, voltage supplied to a probe device, and changes in film thickness in the third substrate processing method. [Figure 13] FIG. 10 is a diagram illustrating an example of a schematic diagram showing supply of a processing gas, supply of a cleaning gas, voltage supplied to a probe device, and changes in film thickness in the fourth substrate processing method. [Figure 14] FIG. 10 is a diagram showing yet another example of a circuit configuration for applying a voltage to a probe device. DETAILED DESCRIPTION OF THE INVENTION

[0008] 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.

[0009] [Plasma processing equipment] 1 shows an example of a cross-sectional view of a plasma processing apparatus 100 according to an embodiment of the present invention. The plasma processing apparatus 100 has a processing chamber 1 that accommodates a substrate W, such as a semiconductor wafer. The plasma processing apparatus 100 is an example of a plasma processing apparatus that performs plasma processing on the substrate W using surface wave plasma formed on the lower surface of a ceiling wall 10 of the processing chamber 1 by microwaves. Examples of plasma processing include film formation processing, etching processing, and ashing processing using plasma.

[0010] The plasma processing apparatus 100 includes a processing vessel 1, a microwave plasma source 2, and a control device 3. The processing vessel 1 is an airtight, substantially cylindrical vessel made of a metal material such as aluminum or stainless steel, and is grounded.

[0011] The processing vessel 1 has a ceiling wall 10, and defines an internal space (plasma generation space U) for plasma processing of the substrate W. The ceiling wall 10 is disk-shaped and serves as a lid that closes the upper opening of the processing vessel 1. A support ring 129 is provided at the contact surface between the processing vessel 1 and the ceiling wall 10, thereby airtightly sealing the interior of the processing vessel 1. The ceiling wall 10 is made of a metal material such as aluminum or stainless steel.

[0012] The microwave plasma source 2 has a microwave output unit 30, a microwave transmission unit 40, and a microwave radiation mechanism 50. The microwave output unit 30 outputs microwaves by distributing them to multiple paths. The microwaves are introduced into the processing vessel 1 through the microwave transmission unit 40 and the microwave radiation mechanism 50. The gas supplied into the processing vessel 1 is excited by the electric field of the introduced microwaves, thereby forming surface wave plasma.

[0013] A mounting table 11 on which a substrate W is placed is provided within the processing vessel 1. The mounting table 11 is supported by a cylindrical support member 12 that stands on the center of the bottom of the processing vessel 1 via an insulating member 12a. Examples of materials that can be used to form the mounting table 11 and the support member 12 include metals such as aluminum whose surfaces have been anodized (anodized), and insulating members (ceramics, etc.) that have high-frequency electrodes inside. The mounting table 11 may also be provided with an electrostatic chuck for electrostatically attracting the substrate W, a temperature control mechanism, a gas flow path for supplying a gas for heat transfer to the backside of the substrate W, and the like.

[0014] A high frequency bias power supply 14 is connected to the mounting table 11 via a matching box 13. When high frequency power is supplied from the high frequency bias power supply 14 to the mounting table 11, ions in the plasma are attracted to the substrate W. Note that the high frequency bias power supply 14 may not be provided depending on the characteristics of the plasma processing.

[0015] An exhaust pipe 15 is connected to the bottom of the processing vessel 1, and an exhaust device 16 including a vacuum pump is connected to the exhaust pipe 15. When the exhaust device 16 is operated, the processing vessel 1 is evacuated, thereby quickly reducing the pressure inside the processing vessel 1 to a predetermined vacuum level. A load / unload port 17 for loading / unloading the substrate W and a gate valve 18 for opening / closing the load / unload port 17 are provided on the sidewall of the processing vessel 1.

[0016] The microwave transmission unit 40 transmits the microwaves output from the microwave output unit 30. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, illustrating an example of the underside of the ceiling wall of the plasma processing apparatus 100. Referring to FIG. 2, a central microwave introduction unit 43b in the microwave transmission unit 40 is disposed at the center of the ceiling wall 10, and six peripheral microwave introduction units 43a are disposed at equal intervals in the circumferential direction around the ceiling wall 10. The central microwave introduction unit 43b and the six peripheral microwave introduction units 43a have the function of introducing microwaves output from the corresponding amplifier units 42 shown in FIG. 1 to the microwave radiation mechanism 50 and the function of matching impedance. Hereinafter, the peripheral microwave introduction unit 43a and the central microwave introduction unit 43b will also be collectively referred to as microwave introduction unit 43.

[0017] 1 and 2, the six dielectric windows 123 on the outer periphery are arranged inside the top wall 10 below the six peripheral microwave introduction portions 43a. The central dielectric window 133 is arranged inside the top wall 10 below the central microwave introduction portion 43b. The number of peripheral microwave introduction portions 43a and dielectric windows 123 is not limited to six and may be two or more. However, the number of peripheral microwave introduction portions 43a is preferably three or more and may be, for example, three to six.

[0018] 1 includes slow-wave plates 121 and 131, slots 122 and 132, and dielectric windows 123 and 133. The slow-wave plates 121 and 131 are formed from a disk-shaped dielectric material that transmits microwaves, and are disposed on the upper surface of the top wall 10. The slow-wave plates 121 and 131 are formed from a material with a relative dielectric constant greater than that of a vacuum, such as quartz, ceramics such as alumina (Al2O3), fluorine-based resins such as polytetrafluoroethylene, or polyimide-based resins. This shortens the wavelength of microwaves that pass through the slow-wave plates 121 and 131 compared to the wavelength of microwaves propagating in a vacuum, thereby enabling the antenna including the slots 122 and 132 to be smaller.

[0019] Below the slow-wave plates 121, 131, dielectric windows 123, 133 are in contact with the backside of the openings in the top wall 10 via slots 122, 132 formed in the top wall 10. The dielectric windows 123, 133 are made of, for example, quartz, ceramics such as alumina (Al2O3), fluorine-based resins such as polytetrafluoroethylene, or polyimide-based resins. The dielectric windows 123, 133 are recessed from the ceiling surface by the thickness of the openings formed in the top wall 10, and supply microwaves to the plasma generation space U.

[0020] The peripheral microwave introduction part 43a and the central microwave introduction part 43b are configured by coaxially arranging a cylindrical outer conductor 52 and a rod-shaped inner conductor 53 provided at the center of the cylindrical outer conductor 52. Microwave power is supplied between the outer conductor 52 and the inner conductor 53, forming a microwave transmission path 44 along which microwaves propagate toward the microwave radiation mechanism 50.

[0021] The peripheral microwave introduction part 43a and the central microwave introduction part 43b are provided with a slug 54 and an impedance adjustment member 140 located at the tip of the slug 54. By moving the slug 54, the impedance of the load (plasma) in the processing vessel 1 can be matched to the characteristic impedance of the microwave power source in the microwave output part 30. The impedance adjustment member 140 is made of a dielectric material and adjusts the impedance of the microwave transmission line 44 by its relative dielectric constant.

[0022] A gas inlet 21 having a shower structure is provided on the ceiling wall 10. Gas supplied from a gas supply source 22 passes through the gas inlet 21 from the gas diffusion chamber 62 via gas supply piping 111 and is supplied into the processing vessel 1 in a shower-like manner. The gas inlet 21 is an example of a gas shower head that supplies gas from a plurality of gas supply holes 60 formed in the ceiling wall 10. Examples of the gas include a gas for plasma generation such as Ar gas, a gas to be decomposed with high energy such as O gas or N gas, and a processing gas such as silane gas.

[0023] Each part of the plasma processing apparatus 100 is controlled by a control device 3. The control device 3 has a microprocessor 4, a ROM (Read Only Memory) 5, and a RAM (Random Access Memory) 6. The ROM 5 and RAM 6 store a process sequence for the plasma processing apparatus 100 and a process recipe, which is a control parameter. The microprocessor 4 controls each part of the plasma processing apparatus 100 based on the process sequence and the process recipe. The control device 3 also has a communication interface (I / F) 7, which enables communication with other devices. The control device 3 also has a display 8, which enables display of the results of performing predetermined control according to the process sequence and the process recipe.

[0024] When performing plasma processing in the plasma processing apparatus 100 configured as described above, first, the substrate W, held on a transfer arm (not shown), is loaded into the processing chamber 1 through the open gate valve 18 and the load / unload port 17. Once the substrate W is transported above the mounting table 11, it is transferred from the transfer arm to a pusher pin, which then lowers to place the substrate W on the mounting table 11. The gate valve 18 is closed after the substrate W is loaded. The pressure inside the processing chamber 1 is maintained at a predetermined vacuum level by the exhaust device 16. A processing gas is introduced into the processing chamber 1 in a shower-like manner from the gas inlet 21. Microwaves radiated from the microwave radiating mechanism 50 via the microwave inlet 43 propagate near the lower surface, which is the inner surface of the ceiling wall. The electric field of the surface-wave microwaves excites the gas, and the substrate W is subjected to plasma processing by the surface-wave plasma generated in the plasma generation space U below the ceiling wall in the processing chamber 1.

[0025] [Probe device] The probe device 70 will be further described with reference to Fig. 1 and Fig. 3. Fig. 3 is a diagram showing an example of the functional configuration of a measurement system and a control device according to an embodiment. As shown in Fig. 1, one or more openings 1b are formed in the circumferential direction in the side wall of the processing vessel 1, and one or more probe devices 70 are attached via a seal member (not shown) that seals between the vacuum space and the atmospheric space.

[0026] A gap of a predetermined width is formed between the tip surface of the probe device 70 and the back surface near the opening 1b of the wall of the processing vessel 1. The gap is designed to be wide enough to prevent DC connection between the probe device 70 and the wall of the processing vessel 1, and narrow enough to prevent plasma and gas from entering. However, the probe device 70 may be attached to an opening formed in the mounting table via a sealing member.

[0027] 3, the measurement system for measuring the plasma state comprises a probe device 70 and a measurement circuit 85. The measurement circuit 85 has a monitor device 80, a blocking capacitor 72, and a coaxial cable 81. The monitor device 80 is connected to the control device 3 so as to be able to communicate with it.

[0028] The probe device 70 is connected to the monitor device 80 via a coaxial cable 81 outside the plasma processing apparatus 100. The monitor device 80 has a signal generator 82, which outputs an AC voltage signal of a predetermined frequency to the coaxial cable 81. The AC voltage signal is transmitted through the coaxial cable 81, and the AC voltage is applied to the probe device 70. The blocking capacitor 72 is connected to the coaxial cable 81, and transmits the AC voltage signal to the probe device 70 and blocks the DC voltage signal. As a result, the monitor device 80 receives only the AC voltage signal from the plasma side.

[0029] The probe device 70 senses the plasma generated in the plasma generation space U. The probe device 70 detects a current signal flowing on the plasma side in response to a signal transmitted to the plasma side, and transmits the signal to the monitor device 80. The current signal flowing on the plasma side is transmitted from the monitor device 80 to the control device 3, and is received by the communication unit 32 of the control device 3. The current value of the received signal is stored in the memory unit 31. The analysis unit 34 of the control unit 33 performs FFT (fast Fourier transform) analysis on the current value of the received signal. The calculation unit 35 of the control unit 33 calculates the plasma electron temperature T e and plasma electron density N e This allows accurate estimation of the plasma state.

[0030] 1. The communication unit 32 is realized by the communication interface 7. The analysis unit 34 and calculation unit 35 of the control unit 33 are realized by the microprocessor 4.

[0031] FIG. 4 is a flowchart showing an example of a method for controlling the plasma processing apparatus 100.

[0032] In step S101, the substrate is processed. Here, the control device 3 controls the gas supply source 22 to supply a processing gas (film forming gas, etching gas, etc.) from the gas supply hole 60 to the plasma generating space U, and controls the microwave output unit 30 and the high frequency bias power supply 14 to generate plasma of the processing gas in the plasma generating space U, and performs the desired processing (film forming processing, etching processing, etc.) on the substrate W. At this time, an AC voltage is applied to the probe device 70 from the signal generator 82, and the probe device 70 senses the plasma generated in the plasma generating space U. Then, the control unit 33 calculates the plasma electron temperature T e and plasma electron density N e is calculated and the plasma state is estimated.

[0033] Here, when the substrate processing is a process for forming an insulating film on the substrate W, an insulator (e.g., SiN, SiO2, etc.) is also deposited on the surface (such as the tip surface of the probe device 70) exposed to the plasma generating space U of the probe device 70 to form an insulating film 200 (see FIGS. 8 and 9 described later). Note that the substrate processing is not limited to a process for forming an insulating film, and may be a process (e.g., etching process) in which an insulator is formed as a reaction by-product and the reaction by-product (insulator) is deposited on the surface of the probe device 70 exposed to the plasma generating space U to form the insulating film 200.

[0034] In step S101, substrate processing is repeated until cleaning start conditions such as a predetermined number of substrates to be processed, processing time, etc. are met. When the predetermined cleaning start conditions are met, the process of the control device 3 proceeds to step S102.

[0035] In step S102, a cleaning process is performed. Here, the control device 3 controls the gas supply source 22 to supply a cleaning gas (e.g., NF3) containing fluorine (F) from the gas supply hole 60 to the plasma generation space U, and controls the microwave output unit 30 and / or the high-frequency bias power supply 14 to generate plasma of the cleaning gas in the plasma generation space U, thereby removing the insulating film deposited in the processing chamber 1. In addition, the insulating film 200 deposited on the surface of the probe device 70 exposed to the plasma generation space U is also removed.

[0036] During the cleaning process, conductive fluoride adheres to and accumulates on the surface of the probe device 70 exposed to the plasma generation space U. The conductive fluoride is, for example, a metal fluoride (e.g., AlF) containing a metal (e.g., Al) derived from the inner wall of the processing chamber 1, the dielectric windows 123, 133 formed of alumina (Al2O3), etc., and fluorine (F) derived from the cleaning gas.

[0037] In step S103, it is determined whether or not the repetition is to be ended. If the repetition is not to be ended (S103: NO), the process of the control device 3 returns to step S101, and the substrate processing and cleaning process are repeated. If the repetition is to be ended (S103: YES), the process of the control device 3 is ended.

[0038] Figure 5 shows an example of a circuit model for the measurement system. Figure 6 shows the estimated plasma electron temperature T e 5(a) is an example of a circuit model when an insulating film 200 is formed on the surface of the probe device 70 exposed to the plasma generating space U. FIG. 5(b) is an example of a circuit model when an insulating film 200 and a conductive fluoride film are formed on the surface of the probe device 70 exposed to the plasma generating space U. FIG. 6(a) is an example of a circuit model when an insulating film 200 is formed on the surface of the probe device 70 exposed to the plasma generating space U. e 6(b) is a graph showing an example of the time change of the estimated plasma electron temperature T e 10 is a graph showing an example of a change over time.

[0039] As shown in FIG. 5(a), in the state where the insulating film 200 is formed, the capacitance component C SiN This capacitance component C SiNis placed in series with the capacitance C of the blocking capacitor 72. Here, the plasma is regarded as a pure resistance with a phase difference of 0°, and the insulating film 200 is regarded as a capacitance component C with a phase difference of 90°. SiN By having the thickness of the insulating film 200 (capacitance component C SiN ) and plasma state (plasma electron temperature T e , plasma electron density N e ) can be estimated separately. Therefore, as shown in FIG. 6(a), the estimated plasma electron temperature T e is the plasma electron temperature T e The true value of (shown by the dashed line) is estimated with high accuracy.

[0040] As shown in FIG. 5(b), in the state where the conductive fluoride film and the insulating film 200 are formed, the resistance component R f , the capacitance component C of the conductive fluoride film f , the capacitance component C due to the insulating film 200 SiN It has.

[0041] If the resistance component Rf is close to 0Ω (i.e., a conductor), the capacitance component C f can be treated as a conductor, ignoring the presence of SiN The plasma state can be estimated by performing calculations similar to those in FIG. 5(a) assuming that the resistance component R f When is close to ∞Ω, the resistance component R f Ignoring the existence of the capacitance component C f Only the capacitance component C in series with the capacitance C of the blocking capacitor 72 needs to be considered. SiN and capacitance component C f The plasma state can be estimated by performing calculations similar to those in FIG. 5(a) assuming that the

[0042] On the other hand, when a conductive fluoride film is formed and the fluoride film has a finite conductivity (in other words, the resistance component R fis not so small as to be regarded as 0Ω, and is not so large as to be regarded as ∞Ω, but has a value in the range between these two. In the calculation process used in FIG. 5(a), the plasma electron temperature T e In other words, the fluoride film has a finite resistance component R f If it contains, the resistance component R f is added to the resistance component of the plasma, making it impossible to determine whether the change in current when measuring the plasma is due to the plasma or the fluoride film. For this reason, as shown in Figure 6(b), the estimated plasma electron temperature T e As time passes, the plasma electron temperature T e In particular, when the conductive fluoride film is AlF, the resistance component R f Impedance and capacitance component C f The impedance is similar to that of the

[0043] 7 is an example of a diagram schematically illustrating the supply of processing gas, the supply of cleaning gas, and changes in voltage and film thickness supplied to the probe device 70 in the first substrate processing method. Here, the supply 502 of processing gas used in step S101 is shown by a dashed line, the supply 501 of cleaning gas used in step S102 is shown by a solid line, the voltage 510 supplied to the probe device 70 is shown by a dashed line, and the film thickness 520 of the insulating film 200 of the probe device 70 is shown by a dashed line.

[0044] As shown in FIG. 7, the voltage (V clean The absolute value of the AC voltage (V) for measurement applied to the probe device 70 when measuring the state of the plasma (during the substrate processing in S101) plasma ) is greater than the absolute value of (|V clean |>|V plasmaAs a result, during the cleaning process (S102), electrons and / or ions are attracted to the surface of the probe device 70 exposed to the plasma generation space U (such as the tip surface of the probe device 70), and the attached conductive fluoride (such as AlF) is removed by sputtering, thereby suppressing the formation of a conductive fluoride film.

[0045] During substrate processing (S101), the AC voltage (V plasma ) is, for example, an AC voltage with an amplitude of 1 V to 2 V (2 to 4 Vpp, 1 to 2 V 0-to-peak). Note that at voltages in this range, the force that attracts electrons and ions is weak, and it is not possible to remove attached conductive fluorides (such as AlF).

[0046] Here, the voltage (V clean ) may be a positive (+) direct current (DC) voltage. In this case, the voltage range is preferably within a range of +5V to +30V. In this case, electrons are attracted to the surface of the probe device 70, and conductive fluorides (AlF, etc.) attached thereto are removed. Note that in the cleaning process (S102), only a positive (+) DC voltage may be applied to the probe device 70, or a positive (+) DC voltage may be superimposed on an AC voltage for measurement and applied to the probe device 70.

[0047] In addition, the voltage (V clean ) may be a negative (-) direct current (DC) voltage. In this case, the voltage range is preferably within a range of -10 V to -100 V. In this case, ions are attracted to the surface of the probe device 70, and conductive fluorides (AlF, etc.) attached thereto are removed. Note that in the cleaning process (S102), only a negative (-) DC voltage may be applied to the probe device 70, or a negative (-) DC voltage may be superimposed on an AC voltage for measurement and applied to the probe device 70.

[0048] In addition, the voltage (V clean ) may be an alternating current (AC) voltage. In this case, the amplitude range is preferably within a range of 5V to 30V. In this case, electrons and ions are attracted to the surface of the probe device 70, and conductive fluorides (such as AlF) attached thereto are removed. Furthermore, by using an AC voltage, electrons and ions can be attracted more suitably than when a DC voltage is used, even when an insulating film 200 is formed on the surface of the probe device 70. Note that in the cleaning process (S102), only an AC voltage may be applied to the probe device 70, or an AC voltage may be superimposed on an AC voltage for measurement and applied to the probe device 70.

[0049] In addition, the voltage (V clean ) may be a pulse voltage. In this case, the voltage range is preferably within a range of −10 V to −100 V in the case of a negative pulse voltage, and preferably within a range of +5 V to +30 V in the case of a positive pulse voltage. In this case, electrons and / or ions are attracted to the surface of the probe device 70, and conductive fluorides (such as AlF) attached thereto are removed. Furthermore, by using a pulse voltage, electrons and / or ions can be attracted more effectively than when a DC voltage is used, even when an insulating film 200 is formed on the surface of the probe device 70. Note that in the cleaning process (S102), only a pulse voltage may be applied to the probe device 70, or a pulse voltage may be superimposed on an AC voltage for measurement and applied to the probe device 70. Furthermore, by controlling the duty ratio of the pulse voltage, the effect of removing conductive fluorides (such as AlF) can be adjusted.

[0050] The cleaning gas may contain a rare gas such as Ar gas in addition to a gas containing fluorine (F) (e.g., NF3, etc.). This allows the Ar ions to sputter and effectively remove conductive fluorides (e.g., AlF) attached to the surface of the probe device 70. Alternatively, a process of cleaning the probe with an inert gas (e.g., Ar, N2, etc.) may be added after cleaning with the cleaning gas.

[0051] In addition, the surface of the probe device 70 may be covered with a coating material (e.g., SiO2) to protect it from the processing gas and the cleaning gas. clean The ion energy based on the cleaning process (S102) is preferably smaller than the critical ion energy of the coating material (for example, 50 eV or less). This prevents the coating material (SiO2) on the surface of the probe device 70 from being etched by the ions in the plasma. Note that the conductive fluoride (AlF, etc.) that adheres in the cleaning process (S102) is deposited on the surface of the probe device 70 as a by-product, and therefore has a small adsorption force, so it can be removed even with an ion energy equal to or lower than the critical ion energy of the coating material.

[0052] FIG. 8 is a diagram showing an example of a circuit configuration for applying a voltage to the probe device 70. In FIG.

[0053] In the example shown in FIG. 8(a), the plasma measurement system includes a probe device 70, a blocking capacitor 72, and a signal generator 82. In this example, one AC power source (signal generator 82) generates an AC voltage (V plasma ) to the probe device 70, and an AC voltage (V clean ) to the probe device 70. That is, the signal generator 82 is configured to be able to change the amplitude of the AC voltage to be applied to the probe device 70, and the AC voltage (V clean) is applied to the probe device 70 during plasma measurement. plasma ) is greater than the absolute value (amplitude) of

[0054] In the example shown in FIG. 8(b), the plasma measurement system includes a probe device 70, a blocking capacitor 72, a signal generator 82 (measurement power supply), a cleaning power supply 91, and a switch 92. The signal generator 82 (measurement power supply) and the cleaning power supply 91 are provided on the opposite side of the blocking capacitor 72 from the probe device 70. The signal generator 82 (measurement power supply) and the cleaning power supply 91 are arranged in series. The switch 92 is configured so that the cleaning power supply 91 can be bypassed and disconnected from the circuit by switching it. The cleaning power supply 91 may be an AC power supply that supplies an AC voltage, or a pulse power supply that supplies a pulse voltage. During plasma measurement, the switch 92 is switched to the ground side, and the signal generator 82 supplies the AC voltage (V plasma ) is applied to the probe device 70. During cleaning, the switch 92 is switched to the cleaning power supply 91 side, and a voltage (V clean ) is applied to the probe device 70.

[0055] In the example shown in FIG. 8(c), the plasma measurement system includes a probe device 70, a blocking capacitor 72, a signal generator 82 (measurement power supply), a cleaning power supply 93, and a switch 94. The signal generator 82 (measurement power supply) and the cleaning power supply 93 are provided on the opposite side of the blocking capacitor 72 from the probe device 70. The signal generator 82 (measurement power supply) and the cleaning power supply 93 are arranged in parallel. The system is configured so that the power supply that supplies voltage to the probe device 70 can be switched by switching the switch 94. The cleaning power supply 93 may be an AC power supply that supplies an AC voltage, or a pulse power supply that supplies a pulse voltage. During plasma measurement, the switch 94 is switched to the signal generator 82 (measurement power supply) side, and the signal generator 82 supplies the AC voltage (V plasma ) is applied to the probe device 70. During cleaning, the switch 94 is switched to the cleaning power supply 93 side, and the voltage (AC voltage or pulse voltage) (V clean ) is applied to the probe device 70.

[0056] FIG. 9 is a diagram showing another example of a circuit configuration for applying a voltage to the probe device 70. In FIG.

[0057] In the example shown in FIG. 9, the plasma measurement system includes a probe device 70, a blocking capacitor 72, a signal generator 82 (measurement power supply), and a cleaning power supply 95. The signal generator 82 (measurement power supply) is provided on the opposite side of the blocking capacitor 72 from the probe device 70, and the cleaning power supply 95 is provided on the same side of the blocking capacitor 72 as the probe device 70. The signal generator 82 (measurement power supply) and the cleaning power supply 95 are arranged in parallel. The cleaning power supply 95 may be a DC power supply that supplies a positive or negative direct current voltage, an AC power supply that supplies an alternating current voltage, or a pulse power supply that supplies a pulse voltage. During plasma measurement, the signal generator 82 generates an AC voltage (V plasma) is applied to the probe device 70. During cleaning, the voltage (either positive or negative DC voltage, AC voltage, or pulse voltage) (V clean ) is applied to the probe device 70. During cleaning, a voltage (V clean ) may be applied to the probe device 70.

[0058] In addition, in the configuration shown in Figure 9, voltage can be applied directly to the probe device 70 without going through the blocking capacitor 72, so a DC power supply that supplies positive or negative DC voltage can be used as the cleaning power supply 95.

[0059] An example of the voltage applied to the probe device 70 will be described with reference to Fig. 10. Fig. 10 is a diagram showing an example of the voltage applied to the probe device 70.

[0060] FIG. 10(a) shows an example of the configuration of FIG. 8(c) (or the configuration of FIG. 9) in which the cleaning power supply 93 (or cleaning power supply 95) is a pulsed power supply that supplies a negative pulse voltage. As shown in FIG. 10(a), during plasma measurement, the signal generator 82 generates an AC voltage (V plasma ) is applied to the probe device 70. During cleaning, a negative pulse voltage (V clean ) is applied to the probe device 70. clean ) is the absolute value of the AC voltage (V plasma ) is greater than the absolute value (amplitude) of

[0061] FIG. 10(b) shows an example of the configuration of FIG. 8(a) (or the configuration of FIG. 9) in which the cleaning power supply (signal generator 82 or cleaning power supply 95 also serving as a cleaning power supply) is an AC power supply. As shown in FIG. 10(b), during plasma measurement, the signal generator 82 generates an AC voltage (V plasma) is applied to the probe device 70. During cleaning, an AC voltage (V clean ) is applied to the probe device 70. Note that the AC voltage (V clean The absolute value (amplitude) of the AC voltage (V plasma ) is greater than the absolute value (amplitude) of

[0062] 10(b), a secondary effect is that the AC voltage for plasma measurement applied to the probe device 70 during cleaning is increased. In conventional measurement methods, the signal is relatively small during cleaning (the plasma electron density is relatively small), making it difficult to estimate the plasma state. In contrast, by increasing the AC voltage for plasma measurement, it is possible to estimate the plasma state even during cleaning. Furthermore, by estimating the plasma state during cleaning, it is also possible to detect the end point of cleaning.

[0063] In the first substrate processing method shown in FIG. 7, during the cleaning process S102, an AC voltage (V plasma ) is applied to the probe device 70, but the present invention is not limited to this.

[0064] 11 is an example of a diagram schematically illustrating the supply of processing gas, the supply of cleaning gas, the voltage supplied to the probe device 70, and changes in film thickness in the second substrate processing method. Here, the supply 502 of processing gas used in step S101 is indicated by a dashed line, the supply 501 of cleaning gas used in step S102 is indicated by a solid line, the voltage 511 supplied to the probe device 70 is indicated by a dashed line, and the film thickness 520 of the insulating film 200 of the probe device 70 is indicated by a two-dot chain line. The second substrate processing method shown in FIG. 11 can be applied to, for example, the circuit configuration shown in FIG. 9. A positive or negative DC power supply can be used as the cleaning power supply 95.

[0065] Step S102 includes a process S111 of applying a first voltage to the probe device 70 and a process S112 of applying a second voltage to the probe device 70.

[0066] In step S111, continuing from step S101, an AC voltage for plasma measurement (first voltage) is applied to the probe device 70. Note that the first voltage is not limited to being equal to the AC voltage for plasma measurement, and includes a case where no AC voltage for plasma measurement is applied. In step S111, the insulating film 200 deposited on the probe device 70 is removed by plasma of a cleaning gas.

[0067] In step S112, a positive or negative DC voltage (second voltage) is applied to the probe device 70. Here, the absolute value of the second voltage is a DC voltage that is greater than the absolute value of the first voltage and greater than the absolute value of the AC voltage for plasma measurement. By applying a cleaning DC voltage after removing the insulating film 200, conductive fluorides can be suitably removed. In particular, by applying a positive DC voltage to the probe device 70, conductive fluorides can be efficiently removed.

[0068] 12 is an example of a diagram schematically illustrating the supply of processing gas, the supply of cleaning gas, the voltage supplied to the probe device 70, and changes in film thickness in the third substrate processing method. Here, the supply 502 of processing gas used in step S101 is shown by a dashed line, the supply 501 of cleaning gas used in step S102 is shown by a solid line, the voltage 512 supplied to the probe device 70 is shown by a dashed line, and the film thickness 520 of the insulating film 200 of the probe device 70 is shown by a dashed line. The third substrate processing method shown in FIG. 12 can be applied to a circuit configuration including a cleaning power supply (when the signal generator 82 in FIG. 8(a) doubles as the cleaning power supply, the cleaning power supply 91 in FIG. 8(b), the cleaning power supply 93 in FIG. 8(c), and the cleaning power supply 95 in FIG. 9) that applies an AC voltage or a pulse voltage (first voltage) to the probe device 70, and a cleaning power supply (cleaning power supply 95 in FIG. 9) that applies a positive or negative DC voltage to the probe device 70.

[0069] Step S102 includes a process S121 of applying a first voltage to the probe device 70 and a process S122 of applying a second voltage to the probe device 70.

[0070] In step S121, an AC voltage or a pulse voltage (first voltage) is applied to the probe device 70. By using the AC voltage or the pulse voltage, it is possible to remove conductive fluoride even when the insulating film 200 is deposited on the probe device 70. Also, in step S121, the insulating film 200 deposited on the probe device 70 is removed by plasma of a cleaning gas.

[0071] In step S122, a positive or negative DC voltage (second voltage) is applied to the probe device 70. Here, the absolute value of the second voltage is a DC voltage that is greater than the absolute value of the first voltage and greater than the absolute value of the AC voltage for plasma measurement. By applying a cleaning DC voltage after removing the insulating film 200, conductive fluorides can be suitably removed. In particular, by applying a positive DC voltage to the probe device 70, conductive fluorides can be efficiently removed.

[0072] 13 is an example of a diagram schematically illustrating the supply of processing gas, the supply of cleaning gas, the voltage supplied to the probe device 70, and changes in film thickness in the fourth substrate processing method. Here, the supply 502 of processing gas used in step S101 is shown by a dashed line, the supply 501 of cleaning gas used in step S102 is shown by a solid line, the voltage 513 supplied to the probe device 70 is shown by a dashed line, and the film thickness 520 of the insulating film 200 of the probe device 70 is shown by a dashed line.

[0073] Here, a voltage obtained by superimposing a DC voltage for cleaning on an AC voltage for plasma measurement is applied to the probe device 70 not only during step S102 but also during step S101.

[0074] FIG. 14 is a diagram showing yet another example of a circuit configuration for applying a voltage to the probe device 70. In FIG.

[0075] 14, the plasma measurement system includes a probe device 70, a blocking capacitor 72, a signal generator 82 (measurement power supply), a cleaning DC power supply 96, and a filter 97. The signal generator 82 (measurement power supply) is provided on the opposite side of the blocking capacitor 72 from the probe device 70, and the cleaning DC power supply 96 is provided on the same side of the blocking capacitor 72 as the probe device 70. The cleaning DC power supply 96 is connected to the probe device 70 via a filter 97 that cuts AC voltage. The signal generator 82 (measurement power supply) and the cleaning DC power supply 96 are arranged in parallel. The cleaning DC power supply 96 is a DC power supply that supplies positive or negative DC voltage.

[0076] With this configuration, the control can be simplified.

[0077] As described above, the substrate processing method of this embodiment can prevent a decrease in the accuracy of estimating the plasma state due to fluoride, which has a finite conductivity, adhering to the probe device 70 during cleaning. In other words, the accuracy of estimating the plasma state by the plasma measurement system can be improved.

[0078] Although the example described above is one in which fluorides having finite conductivity adhere to the probe device 70, the present invention is not limited to this, and can be similarly applied to surface oxides, nitrides, etc. having finite conductivity.

[0079] The above describes the plasma processing apparatus 100, but the present disclosure is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims. [Explanation of symbols]

[0080] 70 Probe Device 72 Blocking Capacitor 80 Monitor Device 81 Coaxial Cable 82 Signal generator (measurement power supply) 85 Measurement circuit 91,93,95 Cleaning power supply 92,94 Switch 200 insulating film

Claims

1. a probe device provided in the plasma processing device; a measurement circuit that outputs an AC voltage for plasma measurement to the probe device and measures a state of plasma generated by the plasma processing device, the absolute value of the voltage applied to the probe device during cleaning of the plasma processing device is greater than the absolute value of the AC voltage used for plasma measurement; A method for controlling a plasma measurement system.

2. During cleaning of the plasma processing apparatus, applying a first voltage to the probe device; applying a second voltage to the probe device after the step of applying the first voltage; The second voltage is the absolute value of the second voltage is greater than the absolute value of the first voltage and is a DC voltage greater than the absolute value of the AC voltage for plasma measurement; The method for controlling the plasma measurement system according to claim 1 .

3. the first voltage is equal to the AC voltage for plasma measurement, or the AC voltage for plasma measurement is not applied; The method for controlling a plasma measurement system according to claim 2 .

4. The first voltage is an AC voltage or a pulse voltage. The method for controlling a plasma measurement system according to claim 2 .

5. As a voltage to be applied to the probe device during cleaning of the plasma processing apparatus, a voltage is applied to the probe device such that ion energy attracted to the probe device is smaller than critical ion energy of a probe surface coating material that covers the probe device. A method for controlling the plasma measurement system according to any one of claims 1 to 4.

6. When cleaning the plasma processing apparatus, plasma of a cleaning gas containing fluorine is generated in a processing vessel of the plasma processing apparatus. A method for controlling the plasma measurement system according to any one of claims 1 to 4.

7. a probe device; a measurement power supply for plasma measurement; a blocking capacitor connected between the probe device and the measurement power supply; a cleaning power supply connected between the blocking capacitor and the probe device and connected in parallel to the measurement power supply; Plasma measurement system.

8. the cleaning power supply is a DC power supply that outputs a DC voltage having an absolute value greater than that of the measurement power supply; The plasma measurement system of claim 7 .

9. the cleaning power supply is an AC power supply that outputs an AC voltage having an absolute value greater than that of the measurement power supply; The plasma measurement system of claim 7 .

10. the cleaning power supply is a pulse power supply that outputs a pulse voltage having an absolute value greater than that of the measurement power supply; The plasma measurement system of claim 7 .

11. a probe device; a measurement power supply for plasma measurement; a blocking capacitor connected between the probe device and the measurement power supply; a cleaning power supply provided on the opposite side of the blocking capacitor from the probe device; Plasma measurement system.

12. the cleaning power supply is connected in series with the measurement power supply; The plasma measurement system of claim 11 .

13. the cleaning power supply is connected in parallel to the measurement power supply; The plasma measurement system of claim 11 .

14. the cleaning power supply is an AC power supply that outputs an AC voltage having an absolute value greater than that of the measurement power supply; The plasma measurement system according to any one of claims 11 to 13.

15. the cleaning power supply is a pulse power supply that outputs a pulse voltage having an absolute value greater than that of the measurement power supply; The plasma measurement system according to any one of claims 11 to 13.

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