Gas inspection method, substrate processing method, and substrate processing system

Abstract

The present invention provides a gas inspection method, a substrate processing method, and a substrate processing system, capable of appropriately inspecting the operation of a secondary valve in a gas supply unit for supplying gas into a processing container of a substrate processing apparatus when it is opened. The gas inspection method includes the following steps: inputting a signal to open the secondary valve; using a secondary pressure gauge to measure the pressure P on the downstream side of a throttle orifice of a flow controller at a time point t after a period of time has passed since the input of the signal to open the secondary valve; using the secondary pressure gauge to measure the standard deviation σ of the pressure on the downstream side of the throttle orifice of the flow controller at a time point t after a period of time has passed since the input of the signal to open the secondary valve; comparing the pressure P with a pressure threshold value P0, and comparing the pressure standard deviation σ with a pressure standard deviation threshold value σ0, to determine whether the opening of the secondary valve is normal.

Description

Technical Field

[0001] The present invention relates to a gas inspection method, a substrate processing method and a substrate processing system. Background Art

[0002] Patent Document 1 discloses a method for inspecting a gas supply system for supplying gas into a processing container of a substrate processing apparatus. The gas supply system includes: a plurality of first pipes, each connected to a plurality of gas sources; a plurality of first valves, each provided on the plurality of first pipes; a plurality of flow controllers, each provided downstream of the plurality of first pipes and connected to the plurality of first pipes; a plurality of second pipes, each provided downstream of the plurality of flow controllers and connected to the plurality of flow controllers; a plurality of second valves, each provided on the plurality of second pipes; a third pipe, provided downstream of the plurality of second pipes and connected to the plurality of second pipes; and a third valve provided on the third pipe.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-59200 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The technology according to the present disclosure appropriately inspects a gas supply unit for supplying gas into a processing container of a substrate processing apparatus, and in particular, appropriately inspects the behavior when a secondary valve is opened.

[0008] Solutions for solving problems

[0009] One embodiment of the present disclosure is a method for inspecting a gas supply unit for supplying gas into a chamber, the gas supply unit comprising: a pipe connected to connect a gas source to the chamber; a flow controller provided in the pipe; a primary valve provided on the upstream side of the flow controller; and a secondary valve provided on the downstream side of the flow controller, wherein the flow controller comprises: a throttle; a primary pressure gauge provided on the upstream side of the throttle; and a secondary pressure gauge provided on the downstream side of the throttle, the method comprising the following steps: step (a), setting, in the flow controller, a threshold value P0 of a pressure on the downstream side of the throttle of the flow controller and a threshold value σ0 of a standard deviation of the pressure at a time point after a period t has passed since a signal for opening the secondary valve was input; In step (b), a signal for opening the secondary valve is input; in step (c), the secondary pressure gauge is used to measure the pressure P on the downstream side of the throttle hole of the flow controller at a time point after a period t has passed since the signal for opening the secondary valve was input; in step (d), the secondary pressure gauge is used to measure the standard deviation σ of the pressure on the downstream side of the throttle hole of the flow controller at a time point after a period t has passed since the signal for opening the secondary valve was input; in step (e), the pressure P measured in step (c) is compared with the pressure threshold value P0 set in step (a), and the standard deviation σ of the pressure measured in step (d) is compared with the pressure standard deviation threshold value σ0 set in step (a) to determine whether the opening of the secondary valve is normal.

[0010] Effects of the Invention

[0011] According to the present disclosure, it is possible to appropriately inspect a gas supply unit for supplying gas into a processing container of a substrate processing apparatus, and in particular, to appropriately inspect the behavior when the secondary valve is opened. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is an explanatory diagram schematically showing the structure of a plasma processing system.

[0013] Figure 2 It is an explanatory diagram showing an outline of the structure of the gas supply unit.

[0014] Figure 3 This is a graph showing the relationship between pressure and flow rate with respect to time when the secondary valve opening and closing behavior is normal and abnormal.

[0015] Figure 4 This is a flowchart showing an example of main steps of a method for inspecting a gas supply unit.

[0016] Description of Reference Numerals

[0017] 1: Plasma processing system; 1a: Plasma processing apparatus; 1b: Control unit; 10: Plasma processing chamber; 10e: Exhaust port; 12a: Gas inlet; 20: Gas supply unit; 21: Gas source; 22: Flow controller; 23: Piping; 24: Primary valve; 25: Secondary valve; 222: Primary pressure gauge; 223: Orifice; 224: Secondary pressure gauge; W: Wafer. DETAILED DESCRIPTION

[0018] In the manufacturing process of semiconductor devices, a plasma processing apparatus excites a processing gas to generate plasma, and this plasma is used to process semiconductor wafers (hereinafter referred to as "wafers"). In this process, a gas supply unit supplies gas into a chamber in the plasma processing apparatus to process the wafers.

[0019] The gas supply volume from the gas supply unit must be strictly managed. However, if the gas flow rate differs from the set value due to a device malfunction, processing within the chamber cannot be performed correctly, potentially resulting in waste wafers. Therefore, Patent Document 1 discloses a method for inspecting a gas supply unit used to supply gas to the chamber of a plasma processing apparatus. Specifically, when a secondary valve located downstream of a flow controller is in its open state during normal operation, control is performed so that an alarm signal is output when the difference between the primary pressure value measured by a primary pressure gauge located upstream of the orifice and the secondary pressure gauge located downstream of the orifice exceeds a threshold value, or when the secondary pressure value exceeds a threshold value.

[0020] In the method for inspecting a gas supply unit disclosed in Patent Document 1, if a malfunction occurs in the opening and closing operation of a secondary valve, the malfunction can be successfully detected if the secondary pressure value rises to a detectable level. However, if a malfunction occurs in which the secondary valve opens but its opening degree is less than the desired degree after a fixed period of time following the input of a signal to open the secondary valve, the secondary pressure value stabilizes at the desired pressure value, making it impossible to distinguish it from a case where the valve is opened at a normal opening degree. Furthermore, the method cannot detect a malfunction in which the valve opens to the desired degree after a fixed period of time following the input of a signal to open the secondary valve, but then opens unstably immediately after the input of the signal to open the secondary valve. While it is possible to confirm the opening and closing operation of the secondary valve in this manner by adding an opening and closing sensor, this requires modification of the device, which increases costs. Therefore, a method is needed to monitor the operation of the secondary valve when it is opened without adding hardware components such as opening and closing sensors.

[0021] The technology disclosed herein appropriately checks the operation when the secondary valve is opened without adding the aforementioned hardware. Below, a plasma processing system as a substrate processing system, a plasma processing method as a substrate processing method, and a gas inspection method according to this embodiment are described with reference to the accompanying drawings. Elements having substantially the same functional structure are denoted by the same reference numerals throughout this specification and the accompanying drawings to omit duplicate descriptions.

[0022] <Plasma processing system>

[0023] First, a plasma processing system according to one embodiment will be described. Figure 1 1 is an explanatory diagram schematically showing the configuration of a plasma processing system 1. In the plasma processing system 1, plasma processing is performed on a wafer W as a substrate. The plasma processing is not particularly limited, and for example, etching processing, film formation processing, diffusion processing, etc. are performed.

[0024] In one embodiment, a plasma processing system 1 includes a plasma processing apparatus 1a and a control unit 1b. The plasma processing apparatus 1a includes a plasma processing chamber 10, a gas supply unit 20, an RF (Radio Frequency) power supply unit 30, and an exhaust system 40. Furthermore, the plasma processing apparatus 1a includes a support unit 11 and an upper electrode shower head 12. The support unit 11 is disposed in the lower region of the plasma processing space 10s within the plasma processing chamber 10. The upper electrode shower head 12 is disposed above the support unit 11 and can function as part of the ceiling of the plasma processing chamber 10.

[0025] The support portion 11 is configured to support the wafer W in the plasma processing space 10s. In one embodiment, the support portion 11 includes a lower electrode 111, an electrostatic chuck 112, and an edge ring 113. The electrostatic chuck 112 is disposed on the lower electrode 111 and is configured to support the wafer W through the upper surface of the electrostatic chuck 112. The edge ring 113 is disposed on the upper surface of the peripheral portion of the lower electrode 111 in a manner surrounding the wafer W. In addition, although not shown in the figure, in one embodiment, the support portion 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck 112 and the wafer W to a target temperature. The temperature control module may include a heater, a flow path, or a combination thereof. A temperature control fluid such as a refrigerant or a heat transfer gas flows in the flow path.

[0026] The upper electrode shower head 12 is configured to supply one or more processing gases from the gas supply unit 20 to the plasma processing space 10s. In one embodiment, the upper electrode shower head 12 includes a gas inlet 12a serving as a gas supply port, a gas diffusion chamber 12b, and a plurality of gas outlets 12c. The gas inlet 12a is fluidically connected to the gas supply unit 20 and the gas diffusion chamber 12b. The plurality of gas outlets 12c are fluidically connected to the gas diffusion chamber 12b and the plasma processing space 10s. In one embodiment, the upper electrode shower head 12 is configured to supply one or more processing gases from the gas inlet 12a via the gas diffusion chamber 12b and the plurality of gas outlets 12c to the plasma processing space 10s.

[0027] The gas supply unit 20 may also include one or more gas sources 21, one or more flow controllers 22, and one or more pipes 23. In one embodiment, the gas supply unit 20 is configured to supply one or more process gases from corresponding gas sources 21 via corresponding flow controllers 22 and pipes 23 to the gas inlet 12a. Each flow controller 22 may also include a so-called pressure-controlled flow controller that controls the flow rate based on the pressure of the process gas. Furthermore, the gas supply unit 20 may also include one or more flow modulation devices that modulate or pulse the flow rate of one or more process gases.

[0028] The RF power supply unit 30 is configured to supply RF power, such as one or more RF signals, to one or more electrodes, such as the lower electrode 111, the upper electrode showerhead 12, or both the lower electrode 111 and the upper electrode showerhead 12. This generates plasma from the one or more process gases supplied to the plasma processing space 10s. Thus, the RF power supply unit 30 can function as at least a portion of a plasma generation unit configured to generate plasma from one or more process gases in a plasma processing chamber. In one embodiment, the RF power supply unit 30 includes a first RF power supply unit 30a and a second RF power supply unit 30b.

[0029] The first RF power supply unit 30a includes a first RF generator 31a and a first matching circuit 32a. In one embodiment, the first RF power supply unit 30a is configured to supply a first RF signal from the first RF generator 31a to the upper electrode showerhead 12 via the first matching circuit 32a. For example, the first RF signal may have a frequency in the range of 27 MHz to 100 MHz.

[0030] The second RF power supply unit 30b includes a second RF generator 31b and a second matching circuit 32b. In one embodiment, the second RF power supply unit 30b is configured to supply a second RF signal from the second RF generator 31b to the lower electrode 111 via the second matching circuit 32b. For example, the second RF signal can have a frequency in the range of 400 kHz to 13.56 MHz. Alternatively, a DC (direct current) pulse generator can be used in place of the second RF generator 31b.

[0031] Although not shown in the figure, other embodiments are contemplated in this disclosure. For example, in an alternative embodiment, the RF power supply unit 30 may be configured to supply a first RF signal from an RF generator to the lower electrode 111, a second RF signal from another RF generator to the lower electrode 111, and a third RF signal from yet another RF generator to the upper electrode showerhead 12. Furthermore, in other alternative embodiments, a DC voltage may be applied to the upper electrode showerhead 12.

[0032] In addition, in various embodiments, the amplitude of one or more RF signals (i.e., the first RF signal, the second RF signal, etc.) may be pulsed or modulated. Amplitude modulation may also include pulsing the RF signal amplitude between an on state and an off state, or between two or more different on states.

[0033] The exhaust system 40 can be connected to, for example, an exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 can also include a pressure valve and a vacuum pump. The vacuum pump can also include a turbomolecular pump, a roughing pump, or a combination thereof.

[0034] In one embodiment, the control unit 1b processes computer-executable instructions that cause the plasma processing apparatus 1a to perform the various processes described herein. The control unit 1b can be configured to control various components of the plasma processing apparatus 1a to perform the various processes described herein. In one embodiment, a portion or all of the control unit 1b is incorporated into the plasma processing apparatus 1a. The control unit 1b may include, for example, a computer 51. The computer 51 may include, for example, a processing unit (CPU) 511, a storage unit 512, and a communication interface 513. The processing unit 511 may be configured to perform various control operations based on programs stored in the storage unit 512. The storage unit 512 may include RAM (Random Access Memory), ROM (Read Only Memory), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 513 may also communicate with the plasma processing apparatus 1a via a communication line such as a LAN (Local Area Network).

[0035] <Gas Supply Section>

[0036] Next, the above-mentioned gas supply unit 20 will be described. Figure 2 It is an explanatory diagram schematically showing the structure of the gas supply unit 20 .

[0037] As described above, the gas supply unit 20 includes one or more gas sources 21, one or more flow controllers 22, and one or more piping 23. Furthermore, the gas supply unit 20 includes one or more primary valves 24 and one or more secondary valves 25. In the piping 23, the primary valve 24 is positioned between the gas source 21 and the flow controller 22, while the secondary valve 25 is positioned downstream of the flow controller 22. Furthermore, a set of gas sources 21, flow controllers 22, piping 23, primary valves 24, and secondary valves 25 is provided depending on the type of process gas.

[0038] The flow controller 22 includes a piezoelectric valve 221, a primary pressure gauge 222, an orifice 223, and a secondary pressure gauge 224. These piezoelectric valve 221, primary pressure gauge 222, orifice 223, and secondary pressure gauge 224 are arranged in the order listed, from upstream to downstream, on the pipe 23. In the following description, the pressure measured by the primary pressure gauge 222 is sometimes referred to as primary pressure P1, and the pressure measured by the secondary pressure gauge 224 is sometimes referred to as secondary pressure P2. The flow controller 22 measures the pressure of the process gas and converts the pressure value into a flow rate value to control the flow rate of the process gas.

[0039] Although various exemplary embodiments have been described above, the present invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and changes can be made. Furthermore, elements in different embodiments can be combined to form other embodiments.

[0040] <Plasma Treatment Method>

[0041] Next, plasma processing performed using the plasma processing system 1 configured as described above will be described.

[0042] First, wafer W is loaded into plasma processing chamber 10 and placed on electrostatic chuck 112. A DC voltage is then applied to the electrodes of electrostatic chuck 112, causing Coulomb force to electrostatically attract and hold wafer W on electrostatic chuck 112. After wafer W is loaded, the interior of plasma processing chamber 110 is depressurized to a desired vacuum level via exhaust system 40.

[0043] Next, the processing gas is supplied from the gas supply unit 20 via the upper electrode showerhead 12 into the plasma processing space 10s. Furthermore, the RF power supply unit 30 supplies high-frequency power HF for generating plasma to the lower electrode 111, thereby exciting the processing gas and generating plasma. At this time, the RF power supply unit 30 may also supply high-frequency power LF for attracting ions. The generated plasma then causes plasma processing on the wafer W.

[0044] To terminate plasma processing, first, the supply of high-frequency power HF from RF power supply unit 30 and the supply of processing gas from gas supply unit 20 are stopped. Furthermore, if high-frequency power LF was supplied during plasma processing, the supply of this high-frequency power LF is also stopped. Next, the supply of heat transfer gas to the back surface of wafer W is stopped, thereby stopping the electrostatic chuck 112 from holding wafer W.

[0045] Thereafter, the wafer W is unloaded from the plasma processing chamber 110 , and a series of plasma processing on the wafer W is completed.

[0046] <Gas Inspection Method>

[0047] In the gas supply unit 20 configured as described above, when gas is supplied from the gas source 21, the secondary valve 25 is opened to the desired opening by a signal from the control unit 1b to open the secondary valve 25. If the secondary valve 25 does not open to the desired opening due to a device failure or other reasons, the secondary pressure P2 will not reach a predetermined pressure value (hereinafter referred to as the "set pressure value"), and the flow rate calculated based on the secondary pressure P2 will also not reach a predetermined flow rate value (hereinafter referred to as the "set flow rate value"). Therefore, it is necessary to check whether the secondary valve 25 normally opens to the desired opening after receiving the signal to open the secondary valve 25.

[0048] In this regard, the inventors of the present invention verified the case where the secondary valve 25 does not open normally after the signal to open the secondary valve 25 is input, and obtained the following findings. That is, compared with the case where the secondary valve 25 is normally opened, in the case where the secondary valve 25 does not open normally, (1) the secondary pressure P2 increases after a fixed period after the signal to open the secondary valve 25 is input. In addition, (2) the standard deviation of the secondary pressure P2 increases after a fixed period after the signal to open the secondary valve 25 is input. With respect to the above findings (1) and (2), Figure 3 This is a graph showing the relationship between the set flow rate value and the pressure value and flow rate value in a certain period before and after the signal for opening the secondary valve 25 is input.

[0049] exist Figure 3 In the figure, t0 represents the time when the signal to open the secondary valve 25 is input. Furthermore, t, indicated by a double-headed arrow, represents the period of, for example, 5 seconds starting from t0. The transition of the set flow rate value when the secondary valve 25 opens normally after the signal to open the secondary valve 25 is input at t0 is indicated by "OK Flow set," and the transition of the flow rate value is indicated by "OK Flow." The transition of the set flow rate value when the secondary valve 25 does not open normally is indicated by "NG Flow set," and the transition of the flow rate value is indicated by "NG Flow." Furthermore, the pressure in the secondary pressure gauge 224 after the period t has elapsed when the secondary valve 25 opens normally after the signal to open the secondary valve 25 is input is indicated by "OK P2," and the pressure in the secondary pressure gauge 224 after the period t has elapsed when the secondary valve 25 does not open normally is indicated by "NG P2."

[0050] Depend on Figure 3 It can be seen that when the secondary valve 25 is normally opened, the flow rate value changes so as to take a value close to the set flow rate value. On the other hand, when the secondary valve 25 is not normally opened, the measured flow rate value changes so as to deviate from the set flow rate value.

[0051] Furthermore, when the secondary valve 25 is normally open, the pressure after a period t is 10 kPa or less, and the standard deviation of the pressure is 1 kPa or less. In contrast, when the secondary valve 25 is not normally open, the pressure after a period t is 30 kPa or more, and the standard deviation of the pressure is 5 kPa or more. The standard deviation of the pressure is calculated based on the pressure continuously measured by the secondary pressure gauge 224 for 5 seconds after the signal to open the secondary valve 25 is input.

[0052] Regarding the findings of (1) above, Figure 3 In the case where the secondary valve 25 does not open normally, the secondary pressure P2 will not decrease even after a fixed period of time after the signal to open the secondary valve 25 is input. This shows that at least the opening of the secondary valve 25 is insufficient, and the gas supplied from the gas source 21 is retained upstream of the secondary valve 25.

[0053] Regarding the finding (2) above, the standard deviation of the measured pressure values ​​when the secondary valve 25 is not normally opened is greater than the standard deviation of the measured pressure values ​​when the secondary valve 25 is normally opened. This indicates that whether the secondary valve 25 is normally opened is correlated with the standard deviation of the secondary pressure P2 during a fixed period after the signal to open the secondary valve 25 is input. The reason for this correlation is believed to be that when the secondary valve 25 is normally opened, the opening of the secondary valve 25 increases at a fixed speed or a fixed acceleration. In contrast, when the secondary valve 25 is not normally opened, the opening of the secondary valve 25 changes irregularly, and this causes deviations in the secondary pressure P2.

[0054] In the method for inspecting the gas supply unit 20 involved in this embodiment based on the above findings (1) and (2), the pressure (secondary pressure P2) after a fixed period after the signal to open the secondary valve 25 is input and the standard deviation of the pressure are measured to check whether the secondary valve 25 is opened normally.

[0055] Figure 4 This is a flowchart showing an example of main steps of a method for inspecting the gas supply unit 20 according to the present embodiment.

[0056] (Process S1)

[0057] In step S1, the pressure threshold value P0 and the pressure standard deviation threshold value σ0, which serve as the inspection reference for the secondary valve 25, are set based on the pressure (secondary pressure P2) measured by the secondary pressure gauge 224 when the secondary valve 25 is normally open and the pressure standard deviation. These pressure threshold value P0 and pressure standard deviation threshold value σ0 may be appropriately determined according to the processing conditions such as the type and flow rate of the gas supplied by the gas supply unit 20, and are not particularly limited. For example, in Figure 3 In the example, the pressure threshold value P0 is set to 50 kPa for the pressure when the secondary valve 25 is not normally opened, thereby enabling detection of a fault in step S7 described below. Furthermore, the pressure threshold value σ0 is set to 5 kPa for the standard deviation of the pressure when the secondary valve 25 is not normally opened, thereby enabling detection of a fault in the step described below.

[0058] Alternatively, under specific processing conditions, with the secondary valve in a normal state (initial state), the pressure P and the pressure standard deviation σ may be measured multiple times. The pressure threshold value P0 and the pressure standard deviation threshold value σ0 may be determined based on the measured values. In one example, the pressure threshold value P0 may be set to a value obtained by multiplying the maximum value of the measured pressure P by an arbitrary coefficient, and the pressure standard deviation threshold value σ0 may be set to a value obtained by multiplying the maximum value of the pressure standard deviation σ by an arbitrary coefficient. For example, for both the pressure P and the pressure standard deviation σ, an arbitrary coefficient may be selected from 1 to 8, preferably from 4 to 6.

[0059] Furthermore, the inventors of the present invention have discovered through experiments that it is preferable to select the pressure threshold value P0 from the range of 10 kPa to 30 kPa, and the pressure standard deviation threshold value σ0 from the range of 1 kPa to 5 kPa. If the pressure threshold value P0 is less than 10 kPa or the pressure standard deviation threshold value σ0 is less than 1 kPa, measurement errors, communication errors, and other factors may cause the secondary valve to be detected as abnormal even if it is normal. On the other hand, if the pressure threshold value P0 exceeds 30 kPa or the pressure standard deviation threshold value σ0 exceeds 5 kPa, even conventional systems such as those described in Patent Document 1 can detect secondary valve abnormalities.

[0060] (Step S2)

[0061] In step S2 , in response to the start of gas supply from the gas source 21 , a signal to open (OPEN) the secondary valve 25 is input.

[0062] (Process S3)

[0063] In step S3, at the point in time t after the signal to open the secondary valve 25 was input in step S2, the secondary pressure gauge 224 measures pressure P (secondary pressure P2). In this embodiment, the period t is, for example, 5 seconds. Furthermore, after careful consideration, the inventors of the present invention have determined that the period t is preferably 5 to 10 seconds. If the period t is less than 5 seconds, measurement errors, communication errors, and other factors may cause the secondary valve to be detected as abnormal even if it is normal. On the other hand, if the period t exceeds 10 seconds, in the case of a fault caused by unstable secondary valve opening, the opening is stabilized after completion of opening, resulting in a reduced standard deviation of the pressure, which may make it impossible to distinguish from a normal condition.

[0064] (Step S4)

[0065] In step S4 , the standard deviation σ of the pressure is calculated based on the secondary pressure P2 measured a plurality of times by the secondary pressure gauge 224 during the period t from the start of the input of the signal to open the secondary valve 25 in step S2 .

[0066] (Step S5)

[0067] In step S5 , it is determined whether the secondary pressure P2 measured in step S3 is less than or equal to the pressure threshold value P0 set in step S1 , and whether the pressure standard deviation σ calculated in step S4 is less than or equal to the pressure standard deviation threshold value σ0 set in step S1 .

[0068] (Step S6)

[0069] When it is determined in step S5 that the pressure P measured in step S3 is below the threshold value P0 of the pressure set in step S1 (P≤P0) and the standard deviation σ of the pressure calculated in step S4 is below the threshold value σ0 of the standard deviation of the pressure set in step S1 (σ≤σ0), it is determined in step S6 that the action of opening the secondary valve 25 is normal and the plasma treatment is continued.

[0070] (Step S7)

[0071] If it is determined in process S5 that the pressure P measured in process S3 is greater than the pressure threshold value P0 set in process S1 (P>P0), or if the standard deviation σ of the pressure calculated in process S4 is greater than the pressure standard deviation threshold value σ0 set in process S1 (σ>σ0), it is determined in process S7 that the action of opening the secondary valve 25 is unstable and the plasma processing is stopped.

[0072] According to the above embodiment, it is possible to appropriately inspect the gas supply unit 20 for supplying gas into the plasma processing chamber 10 of the plasma processing apparatus 1a. In particular, it is possible to appropriately inspect the behavior of the secondary valve 25 when it is opened. Specifically, by comparing the measured secondary pressure P2 with the pressure threshold value P0 and comparing the pressure standard deviation σ with the pressure standard deviation threshold value σ0, it is possible to appropriately inspect the behavior of the secondary valve 25 when it is opened.

[0073] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive, and the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope of the appended claims and the spirit thereof.

Claims

1. A gas inspection method for inspecting a gas supply unit, wherein: The gas supply part is used to supply gas into the chamber. The gas supply unit includes: a pipe connected to connect a gas source to the chamber; a flow controller, which is provided on the pipe; a primary valve disposed upstream of the flow controller; and A secondary valve is provided on the downstream side of the flow controller, Wherein, the flow controller has: throttle hole; a primary pressure gauge disposed on the upstream side of the throttle hole; and A secondary pressure gauge is provided on the downstream side of the orifice. The method comprises the following steps: Step (a) of setting, in the flow controller, a threshold value P0 of the pressure on the downstream side of the orifice of the flow controller and a threshold value σ0 of the standard deviation of the pressure at a time point t after a signal for opening the secondary valve is input; Step (b), inputting a signal to open the secondary valve; (c) measuring, using the secondary pressure gauge, the pressure P on the downstream side of the orifice of the flow controller at a time point when a period t has elapsed since a signal to open the secondary valve was input; (d) measuring, using the secondary pressure gauge, a standard deviation σ of the pressure on the downstream side of the orifice of the flow controller at a time point after a period t has elapsed since a signal to open the secondary valve was input; and Step (e) compares the pressure P measured in step (c) with the threshold value P0 of the pressure set in step (a), and compares the standard deviation σ of the pressure measured in step (d) with the threshold value σ0 of the standard deviation of the pressure set in step (a) to determine whether the opening of the secondary valve is normal.

2. The gas inspection method according to claim 1, wherein: The pressure threshold value P0 and the pressure standard deviation threshold value σ0 serving as inspection criteria for the secondary valve are set based on the pressure and the pressure standard deviation measured by the secondary pressure gauge when the secondary valve is normally open.

3. The gas inspection method according to claim 1, wherein: The pressure and the standard deviation of the pressure are measured a plurality of times while the secondary valve is in a normal state, and a threshold value P0 of the pressure and a threshold value σ0 of the standard deviation of the pressure are determined based on the obtained measurement values.

4. The gas inspection method according to claim 3, characterized in that: The pressure threshold value P0 is set to a value obtained by multiplying the maximum value of the pressure measured when the secondary valve is in a normal state by an arbitrary coefficient, and the pressure standard deviation threshold value σ0 is set to a value obtained by multiplying the maximum value of the standard deviation of the pressure measured when the secondary valve is in a normal state by the arbitrary coefficient.

5. The gas inspection method according to claim 4, characterized in that: In the case of either the pressure or the standard deviation of the pressure, the arbitrary coefficient is 1 to 8.

6. The gas inspection method according to any one of claims 1 to 5, characterized in that: The threshold value P0 of the pressure on the downstream side of the orifice of the flow controller at the time point t after the signal to open the secondary valve is input is set in the step (a) to be 10 kPa to 30 kPa, and the threshold value σ0 of the standard deviation of the pressure is set to be 1 kPa to 5 kPa.

7. The gas inspection method according to any one of claims 1 to 5, characterized in that: The period t in the steps (a), (c), and (d) is 5 to 10 seconds.

8. The gas inspection method according to any one of claims 1 to 5, characterized in that: It also includes a step (f), in which, when it is determined in the step (e) that the pressure P measured in the step (c) is below the threshold value P0 of the pressure set in the step (a) and the standard deviation σ of the pressure measured in the step (d) is below the threshold value σ0 of the standard deviation of the pressure set in the step (a), it is determined in the step (f) that the action of opening the secondary valve is normal.

9. A substrate processing method comprising the gas inspection method according to any one of claims 1 to 8, In this substrate processing method, the substrate is processed using the gas supplied from the gas supply unit.

10. A substrate processing system for processing a substrate using a gas, the substrate processing system comprising: a chamber having a gas supply port and a gas exhaust port; a gas supply portion that supplies gas to the chamber; and Control Department, in, The gas supply unit includes: a pipe connected to connect a gas source to the chamber; a flow controller, which is provided on the pipe; a primary valve disposed upstream of the flow controller; and A secondary valve is provided on the downstream side of the flow controller, Wherein, the flow controller has: throttle hole; a primary pressure gauge disposed on the upstream side of the throttle hole; and A secondary pressure gauge is provided on the downstream side of the orifice. The control unit controls the system to perform a process including the following steps: Step (a) of setting, in the flow controller, a threshold value P0 of the pressure on the downstream side of the orifice of the flow controller and a threshold value σ0 of the standard deviation of the pressure at a time point t after a signal for opening the secondary valve is input; Step (b), inputting a signal to open the secondary valve; (c) measuring, using the secondary pressure gauge, a pressure value P on the downstream side of the orifice of the flow controller at a time point when a period t has elapsed since a signal to open the secondary valve was input; (d) measuring, using the secondary pressure gauge, a standard deviation σ of the pressure on the downstream side of the orifice of the flow controller at a time point after a period t has elapsed since a signal to open the secondary valve was input; and Step (e) compares the pressure P measured in step (c) with the threshold value P0 of the pressure set in step (a), and compares the standard deviation σ of the pressure measured in step (d) with the threshold value σ0 of the standard deviation of the pressure set in step (a) to determine whether the opening of the secondary valve is normal.

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