Substrate processing method and substrate processing system

Abstract

The present invention provides a substrate processing method and a substrate processing system, which can monitor the total flow rate of the gas supplied for substrate processing with high precision. As a method for processing a substrate using the gas supplied to the chamber, the method includes the following steps: step (a), setting a threshold value of the pressure of the gas to be controlled in a flow controller that measures the pressure of the gas supplied to the chamber to control the flow rate of the gas; step (b), supplying gas into the chamber; step (c), measuring the pressure of the gas in the flow controller; step (d), stopping the supply of gas into the chamber; step (e), calculating the time during which the pressure of the gas measured in step (c) is equal to or higher than the threshold value; and step (f), calculating the total flow rate of the gas supplied to the chamber based on the pressure of the gas measured in step (c) and the time calculated in step (e).

Description

Technical Field

[0001] The present disclosure relates to a substrate processing method and a substrate processing system. Background Art

[0002] In Patent Document 1, a flow rate measurement method of a flow rate controller for controlling the flow rate of a gas used in a gas supply device of a semiconductor manufacturing apparatus is disclosed. As a method for measuring the flow rate of a gas, a lamination method is used.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-32983 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] The technology related to the present disclosure monitors the total flow rate of a gas supplied for substrate processing with high precision.

[0008] Solutions for Solving the Problems

[0009] One aspect of the present disclosure is a method for processing a substrate using a gas supplied to a chamber, the method including the following steps: step (a), setting a threshold value of the pressure of a gas to be controlled in a flow rate controller that measures the pressure of the gas supplied to the chamber to control the flow rate of the gas; step (b), supplying the gas into the chamber; step (c), measuring the pressure of the gas in the flow rate controller; step (d), stopping the supply of the gas into the chamber; step (e), calculating the time during which the pressure of the gas measured in step (c) is equal to or higher than the threshold value; and step (f), calculating the total flow rate of the gas supplied to the chamber based on the pressure of the gas measured in step (c) and the time calculated in step (e).

[0010] Effects of the Invention

[0011] According to the present disclosure, the total flow rate of a gas supplied for substrate processing can be monitored with high precision. Brief Description of the Drawings

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

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

[0014] Figure 3 It is an explanatory diagram showing the supply / stop of the processing gas.

[0015] Figure 4 It is an explanatory diagram showing the supply / stop of the processing gas.

[0016] Figure 5 It is an explanatory diagram showing the fine adjustment during gas supply.

[0017] Figure 6 It is a flowchart showing an example of the main process of the method for monitoring the processing gas.

[0018] Figure 7 It is an explanatory diagram showing the situation where the supply / stop of the processing gas is repeated.

[0019] Explanation of Reference Signs

[0020] 1: Plasma processing system; 1a: Plasma processing apparatus; 1b: Control unit; 10: Plasma processing chamber; 20: Gas supply unit; 22: Flow controller; W: Wafer. Detailed implementation mode

[0021] In the manufacturing process of semiconductor devices, processing such as etching is performed on a semiconductor wafer (hereinafter referred to as "wafer"). As an etching method, for example, there is ALE (Atomic Layer Etching). In ALE, a chemical modification process that only acts on the outermost atomic layer of the wafer and an etching process that only removes the chemically modified part are alternately repeated to etch the atomic layer of the target film layer by layer.

[0022] In an etching apparatus for performing ALE, the wafer disposed inside the chamber is processed by the gas supplied from the gas supply device into the inside of the chamber. In addition, the gas supply device includes a flow controller for controlling the flow rate of the gas to supply the gas at an appropriate flow rate. The flow controller uses, for example, a pressure control type flow controller.

[0023] In the ALE process, in order to perform the above-described chemical modification process and etching process, the switching of gases is repeated, and the supply and stop of gases are performed within a short period of time. In the following description, the state of supplying gas may be referred to as "gas supply", and the stop of gas supply may be referred to as "gas stop". Moreover, since the supply / stop of gas is performed within such a short period of time, the ratio of the portion where the gas flow rate increases from zero to the desired flow rate (hereinafter referred to as "rise") to the portion where the gas flow rate decreases from the desired flow rate to zero (hereinafter referred to as "fall") becomes large. Since it is mostly impossible to ensure these rise and fall operations by a flow controller, the accuracy of gas flow control in the flow controller is poor, which may lead to deterioration of the reproducibility of the gas flow rate.

[0024] In addition, in the ALE process, for example, data is collected by measuring the gas supply time using a plate (circuit board) provided in the etching apparatus. However, as described above, the gas supply time is short, so the ratio of communication errors becomes large. As a result, the reproducibility of the gas flow rate deteriorates due to the influence of communication errors.

[0025] Moreover, since the flow controller is operating, it is impossible to ensure the reproducibility of gas flow control. In other words, the responsiveness of the flow controller cannot follow the supply / stop of gas within a short period of time. From this viewpoint, the reproducibility of the gas flow rate is also poor.

[0026] On the other hand, in the ALE process where gas supply / stop is performed within such a short period of time, it is necessary to monitor the gas flow rate in real time and with high precision during the process. If the gas flow rate is monitored in real time like this, abnormal processes can be detected, and thus the yield of product wafers can be increased.

[0027] The technology related to the present disclosure measures the total flow rate of gas supplied for substrate processing with high precision. Hereinafter, a plasma processing system as a substrate processing system and a plasma processing method as a substrate processing method according to the present embodiment will be described with reference to the drawings. In addition, in this specification and the drawings, elements having substantially the same functional structure are given the same reference numerals, and thus redundant descriptions are omitted.

[0028] <Plasma Processing System>

[0029] First, a plasma processing system according to an embodiment will be described. Figure 1 It is an explanatory diagram showing an outline of the structure of the plasma processing system 1. In the plasma processing system 1, an ALE process is performed on a wafer W as a substrate.

[0030] In one embodiment, the 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. In addition, the plasma processing apparatus 1a includes a support portion 11 and an upper electrode showerhead 12. The support portion 11 is disposed in a lower region of the plasma processing space 10s within the plasma processing chamber 10. The upper electrode showerhead 12 is disposed above the support portion 11 and can function as a part of the ceiling of the plasma processing chamber 10.

[0031] 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 by 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 so as to surround the wafer W. In addition, although not shown, 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 also 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.

[0032] The upper electrode showerhead 12 is configured to supply one or more process gases from the gas supply unit 20 to the plasma processing space 10s. In one embodiment, the upper electrode showerhead 12 has a gas inlet 12a as a gas supply port, a gas diffusion chamber 12b, and a plurality of gas outlets 12c. The gas inlet 12a is in fluid communication with the gas supply unit 20 and the gas diffusion chamber 12b. The plurality of gas outlets 12c are in fluid communication with the gas diffusion chamber 12b and the plasma processing space 10s. In one embodiment, the upper electrode showerhead 12 is configured to supply one or more process gases from the gas inlet 12a to the plasma processing space 10s via the gas diffusion chamber 12b and the plurality of gas outlets 12c.

[0033] The gas supply unit 20 may also include one or more gas sources 21, one or more flow controllers 22, and one or more gas supply paths 23. In one embodiment, the gas supply unit 20 is configured to supply one or more process gases from the corresponding gas sources 21 to the gas inlet 12a via the corresponding flow controllers 22 and gas supply paths 23, respectively. Each flow controller 22 may include, for example, a so-called pressure control type flow controller that controls the flow rate by the pressure of the process gas. Further, the gas supply unit 20 may include one or more flow modulation devices that modulate or pulse the flow rate of one or more process gases.

[0034] 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. Thereby, plasma is generated from one or more process gases supplied to the plasma processing space 10s. Accordingly, the RF power supply unit 30 can function as at least a part of a plasma generation unit configured to generate plasma from one or more process gases in the 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.

[0035] The first RF power supply unit 30a includes a first RF generation unit 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 generation unit 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.

[0036] The second RF power supply unit 30b includes a second RF generation unit 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 generation unit 31b to the lower electrode 111 via the second matching circuit 32b. For example, the second RF signal may have a frequency in the range of 400 kHz to 13.56 MHz. In addition, a DC (Direct Current) pulse generation unit may be used instead of the second RF generation unit 31b.

[0037] Further, although not shown, other embodiments are contemplated in the present disclosure. For example, in an alternative embodiment, the RF power supply unit 30 may also be configured to supply a first RF signal from the RF generation unit to the lower electrode 111, supply a second RF signal from another RF generation unit to the lower electrode 111, and supply a third RF signal from yet another RF generation unit to the upper electrode showerhead 12. In addition, a DC voltage may be applied to the upper electrode showerhead 12 in other alternative embodiments.

[0038] Additionally, 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. The 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.

[0039] The exhaust system 40 can be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may also include a pressure valve and a vacuum pump. The vacuum pump may also include a turbomolecular pump, a roughing pump, or a combination thereof.

[0040] In one embodiment, the control unit 1b processes computer-executable commands that cause the plasma processing apparatus 1a to perform the various processes described in the present disclosure. The control unit 1b can be configured to control the respective elements of the plasma processing apparatus 1a to perform the various processes described herein. In one embodiment, a part or all of the control unit 1b is included in the plasma processing apparatus 1a. The control unit 1b may, for example, include a computer 51. The computer 51 may, for example, include a processing unit (CPU: Central Processing Unit) 511, a storage unit 512, and a communication interface 513. The processing unit 511 can be configured to perform various control operations based on programs stored in the storage unit 512. The storage unit 512 may also include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 513 may communicate with the plasma processing apparatus 1a via a communication line such as a LAN (Local Area Network).

[0041] <Gas supply unit>

[0042] Next, the above-described gas supply unit 20 will be described. Figure 2It is an explanatory diagram showing an outline of the structure of the gas supply unit 20.

[0043] 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 gas supply paths 23. In addition, the gas supply unit 20 further includes one or more primary valves 24 and one or more secondary valves 25. In the gas supply path 23, a primary valve is provided between the gas source 21 and the flow controller 22, and the secondary valve is arranged on the downstream side of the flow controller 22. Moreover, the gas source 21, the flow controller 22, the gas supply path 23, the primary valve 24, and the secondary valve 25 are provided in groups according to the type of the processing gas.

[0044] 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 this order from the upstream side to the downstream side in the gas supply path 23. In addition, in the following description, the pressure measured by the primary pressure gauge 222 is sometimes referred to as the primary pressure P1, and the pressure measured by the secondary pressure gauge 224 is sometimes referred to as the secondary pressure P2. Moreover, the flow controller 22 measures the pressure of the processing gas and converts the pressure value into a flow value to control the flow rate of the processing gas.

[0045] Although the above various exemplary embodiments have been described, it is not limited to the above exemplary embodiments, and various additions, omissions, substitutions, and changes can be made. In addition, elements in different embodiments can be combined to form other embodiments.

[0046] <ALE process>

[0047] Next, the ALE process performed using the plasma processing system configured as described above will be described.

[0048] (Chemical modification process)

[0049] For example, Cl2 (chlorine) gas is supplied from the gas supply unit 20 to the inside of the plasma processing chamber 10 as a processing gas, and the Cl2 (chlorine) gas is adsorbed on the surface of the wafer W (silicon) to be modified into a SiCl compound.

[0050] (Etching process)

[0051] For example, Ar (argon) gas is supplied from the gas supply unit 20 to the inside of the plasma processing chamber 10 as a processing gas, and Ar ions are generated. Moreover, the SiCl compound on the surface of the wafer W is selectively etched by the Ar ions.

[0052] Moreover, the above chemical modification process and etching process are alternately repeated to etch the atomic layers of the target film layer by layer. In addition, the chemical modification process and the etching process use generally known methods.

[0053] <Gas monitoring method>

[0054] As described above, in the ALE process, in order to perform the chemical modification process and the etching process, the switching of the process gas is repeated, and the supply / stop of the process gas is performed in a short time. In the ALE process in which the supply / stop of the process gas is performed in such a short time, it is necessary to monitor the gas flow rate in real time and with high accuracy during the process.

[0055] Here, first, the inventors of the present invention considered using the output value of the gas flow rate from the flow controller 22 for monitoring. Figure 3 It is an explanatory diagram showing the supply / stop of the process gas. In Figure 3 ,"Gas set flow rate" represents the set value of the flow rate of the process gas, "gas flow rate" represents the gas flow rate output by the flow controller 22, and "gas P1 pressure" represents the gas pressure measured by the flow controller 22, specifically the primary pressure P1.

[0056] In Figure 3 's example, the total flow rate of the process gas is monitored by monitoring the area of the "gas flow rate" (the shaded part in Figure 3 ). However, in this case, even if the actually flowing gas flow rate is the same, due to the flow rate conversion of the flow controller 22, the rise and fall of the gas flow rate (the part surrounded by the circle in Figure 3 ) may shift. That is, in the flow controller 22, the pressure value is converted into a flow rate value according to the conversion point and setting of the control method, and even if the internal pressure value (pressure data) is the same, the flow rate output may sometimes be different.

[0057] Since it is mostly impossible to guarantee these rise and fall operations by the flow controller 22, it is preferable to manage the individual differences and reproducibility of the flow controller 22 by the plasma processing apparatus 1a and the control unit 1b. In addition, in the flow controller 22, it is appropriate to detect the case where the actually flowing gas flow rates are the same (pressure waveforms are the same) and detect the case where the actually flowing gas flow rates are different (pressure waveforms are shifted).

[0058] Therefore, the inventors of the present invention considered using the pressure output value of the flow controller 22 to monitor the gas flow rate. Figure 4 It is an explanatory diagram showing the supply / stop of the process gas. In Figure 4In this case, "gas set flow rate" represents the set value of the flow rate of the processing gas, "gas flow rate" represents the gas flow rate output by the flow controller 22, and "gas P1 pressure" represents the gas pressure measured by the flow controller 22, specifically the primary pressure P1.

[0059] In Figure 4 the example of Figure 4 , the total flow rate of the processing gas is monitored by monitoring the area of the "gas flow rate" (

[0060] the shaded part in

[0061] ). However, in this case, when the gas stops, the flow controller 22 also shows the residual gas pressure, so the primary pressure P1 of the processing gas is not 0 (zero). Therefore, when the residual gas pressure is large or the gas stop time is long, the accuracy of the gas flow rate decreases.

[0062] F = P1 × Fs(t) / Ps(t) ··· (1)

[0063] F: Flow rate of the standardized gas (sccm), P1: Primary pressure of the flow controller 22 (psi), t: Elapsed time from the start of gas supply (min), Fs(t): Set value of the gas flow rate at time t (sccm), Ps(t): Primary pressure of the flow controller 22 at time t (psi)

[0064] In this case, if the flow rates of the actually flowing processing gases are the same, the same gas flow rate can be calculated in each flow controller 22 according to the above formula (1). As a result, the individual differences of the flow controllers 22 can be eliminated.

[0065] In addition, as Figure 4 shown in

[0066] , in the ALE process, when integrating the data of (gas flow rate) × (time) to calculate the total flow rate of the processing gas, since the primary pressure P1 of the flow controller 22 is not 0 (zero) when the gas stops, the pressure data at the time of gas stop is also converted into a flow rate. Therefore, in this embodiment, only the waveform when the processing gas is supplied (hereinafter referred to as "fine tuning") is extracted. Figure 5As shown, a threshold value Pt of the primary pressure P1 is preset. Regarding this threshold value Pt, for example, at the start-up of the device or the like, data on the gas flow rate of the flow controller 22 and the actual gas flow rate data are acquired to determine the threshold value Pt corresponding to the ALE process. Moreover, the time T during which the primary pressure P1 is equal to or higher than the threshold value Pt is calculated.

[0067] This time T may include a forward time Ta before the primary pressure P1 reaches the threshold value Pt when the primary pressure P1 is rising. In addition, the time T may include a backward time Tb after the primary pressure P1 reaches the threshold value Pt when the primary pressure P1 is falling. Regarding the forward time Ta and the backward time Tb, for example, at the start-up of the device or the like, data on the gas flow rate of the flow controller 22 and the actual gas flow rate data are acquired to determine the forward time Ta and the backward time Tb corresponding to the ALE process.

[0068] In this case, even if the primary pressure P1 of the flow controller 22 is not 0 (zero) when the gas stops, this part can be removed. Therefore, when converting the primary pressure P1 into a gas flow rate, the flow rate during gas supply can be appropriately calculated.

[0069] As described above, by performing flow rate conversion and standardization on the primary pressure P1 of the flow controller 22 and only performing fine adjustment during gas supply, the total flow rate of the process gas can be calculated with high precision. In addition, by always monitoring in real time the gas flow rate supplied through the ALE process, wafers W with abnormalities can be detected in advance.

[0070] Next, a method for monitoring the process gas using the above standardization of the primary pressure P1 and fine adjustment only during gas supply will be described. Figure 6 It is a flowchart showing an example of the main steps of the method for monitoring the process gas.

[0071] (Step S1)

[0072] In step S1, before performing the ALE process, the process of this ALE process is set. Specifically, the set value Fs(t) of the gas flow rate and the set value Ps(t) of the gas pressure at the elapsed time t from the start of gas supply are set.

[0073] In addition, in step S1, Figure 5 the threshold value Pt of the primary pressure P1 shown is preset. In addition, the forward time Ta when the primary pressure P1 is rising and the backward time Tb when it is falling are also preset. These threshold value Pt, forward time Ta, and backward time Tb can be set by acquiring data on the gas flow rate of the flow controller 22 and the actual gas flow rate data, for example, at the start-up of the device or the like.

[0074] (Step S2)

[0075] When the prior setting in process S1 is completed, the ALE process is started for the wafer W placed inside the plasma processing chamber 10. That is, in process S2, the supply of the processing gas from the gas supply unit 20 to the inside of the plasma processing chamber 10 is started.

[0076] (Process S3)

[0077] In process S3, during the supply of the processing gas, the primary pressure P1 of the processing gas is measured by the flow controller 22.

[0078] (Process S4)

[0079] In process S4, the primary pressure P1 of the processing gas measured by the flow controller 22 is converted into a gas flow rate using the following formula (1) for standardization.

[0080] F = P1 × Fs(t) / Ps(t) ··· (1)

[0081] F: Standardized gas flow rate (sccm), P1: Primary pressure of the flow controller 22 (psi), t: Elapsed time from the start of gas supply (min), Fs(t): Set value of the gas flow rate at time t (sccm), Ps(t): Primary pressure of the flow controller at time t (psi)

[0082] (Process S5)

[0083] When the ALE process for the wafer W is completed, in process S5, the supply of the processing gas from the gas supply unit 20 to the inside of the plasma processing chamber 10 is stopped.

[0084] (Process S6)

[0085] In process S6, the time T during which the primary pressure P1 of the processing gas measured in process S3 is equal to or higher than the threshold value Pt set in process S1 is calculated. Specifically, the time T including the forward time Ta and the backward time Tb as shown is calculated. Then, it is possible to extract only the waveform of the pressure during gas supply within this time T for fine adjustment. Figure 5 As shown, including the forward time Ta and the backward time Tb. Then, it is possible to extract only the waveform of the pressure during gas supply within this time T for fine adjustment.

[0086] (Process S7)

[0087] In process S7, the total flow rate of the processing gas is calculated by integrating the standardized gas flow rate F in process S4 over the time T calculated in process S6. The total flow rate of this processing gas is the total flow rate of the processing gas supplied from the gas supply unit 20 to the plasma processing chamber 10 during one gas supply / stop.

[0088] (Process S8)

[0089] In Process S8, it is determined whether the total flow rate of the process gas calculated in Process S7 is within the desired range. The desired range is preset before performing the ALE process according to the manufacturing process of the ALE process. For example, in Process S1, data on the gas flow rate of the flow controller 22 and the actual gas flow rate data can be obtained at the start of the device or the like for setting. Additionally, for example, gas supply / stop can be repeated to calculate the average value of these gas flow rates.

[0090] (Process S9)

[0091] In Process S9, when it is determined in Process S8 that the total flow rate of the process gas is within the desired range, the ALE process continues.

[0092] (Process S10)

[0093] In Process S10, when it is determined in Process S8 that the total flow rate of the process gas is outside the desired range, the set value Fs(t) of the gas flow rate of the flow controller 22 is feedback-controlled for adjustment.

[0094] The above Processes S1 to S10 are performed, and the total flow rate of the process gas is monitored during one gas supply / stop.

[0095] According to the above embodiment, in Process S4, the primary pressure P1 of the flow controller 22 is converted into a flow rate for standardization. Therefore, if the flow rates of the actually flowing process gases are the same, the same gas flow rate can be calculated in each flow controller 22 according to the above formula (1). As a result, the individual differences of the flow controllers 22 can be eliminated.

[0096] In addition, in Process S6, the time T can be calculated, and only the waveform of the pressure during gas supply is extracted for fine adjustment. In other words, even if the primary pressure P1 of the flow controller 22 is not 0 (zero) during gas stop, this part can be removed. Therefore, the flow rate during gas supply can also be appropriately calculated when converting the primary pressure P1 into a gas flow rate.

[0097] In addition, Processes S2 to S7 can be executed in real time. Moreover, the total flow rate of the process gas can be monitored in real time and with high precision in a manner that includes the rise and fall that cannot be guaranteed by the flow controller 22. In particular, in the case where gas supply / stop is short, such as 3 seconds or less as in the ALE process, the influence of the rise and fall becomes large. Therefore, the gas monitoring method of this embodiment is useful. As a result, by always monitoring in real time the gas flow rate supplied through the ALE process, wafers W with abnormalities can be detected in advance.

[0098] Moreover, in the present embodiment, it is possible to monitor the total flow rate of the processing gas in real time without changing the gas supply path 23. Here, when the gas supply path 23 is changed, the responsiveness of the processing gas with respect to the plasma processing chamber 10 changes. In this regard, in the present embodiment, it is possible to accurately monitor the total flow rate of the processing gas without changing the responsiveness.

[0099] In the above embodiment, a method for monitoring the total flow rate of the processing gas during one gas supply / stop has been described. In this regard, in the ALE process, the chemical modification process and the etching process are alternately repeated, so the supply / stop of the processing gas is repeated as Figure 7 shown. In addition, the number of times of gas supply / stop is not limited to the illustrated example and can be arbitrarily set.

[0100] Therefore, in step S7, the total gas flow rate for multiple times can be averaged as the total gas flow rate for one gas supply / stop. In this case, even if the deviation of the total gas flow rate calculated in step S7 is large at each gas supply / stop, it can be averaged. Thus, the accuracy in determining the total flow rate of the processing gas in step S8 can be improved.

[0101] In step S10 of the above embodiment, feedback control is performed on the set value Fs(t) of the gas flow rate of the flow controller 22. In this regard, for one wafer W, the determination result of the total gas flow rate for one gas supply / stop can be fed back to the set value Fs(t) of the gas flow rate for the next gas supply / stop. Alternatively, the determination result of the total gas flow rate for one wafer W can be fed back to the set value Fs(t) of the gas flow rate for the next wafer W to be processed.

[0102] In addition, in step S10 of the above embodiment, feedback control is performed on the set value Fs(t) of the gas flow rate, but it is not necessary to perform feedback control necessarily. When it is determined in step S8 that the total flow rate of the processing gas is outside the desired range, for example, the ALE process can be stopped.

[0103] In the above embodiment, both the flow rate conversion and normalization of the primary pressure P1 in step S4 and the fine adjustment during gas supply in step S6 are performed, but step S4 can be omitted. That is, the value of the primary pressure P1 itself can be used for fine adjustment during gas supply. In this case, it is also possible to appropriately monitor the total flow rate of the processing gas.

[0104] The gas supply unit 20 of the above-described embodiment may include a board (not shown) that collects data such as the primary pressure P1 measured by the primary pressure gauge 222, the secondary pressure P2 measured by the secondary pressure gauge 224, and the data of the gas supply time. The board is, for example, a circuit board dedicated to data collection. Here, when a board is provided in the plasma processing chamber 10 as in the past, the proportion of communication errors when collecting data of the gas supply unit 20 is large. In this regard, if the gas supply unit 20 includes a board, the proportion of such communication errors is small, so that the reproducibility of the flow controller 22 can be further improved.

[0105] In the above embodiment, the method for monitoring the total flow rate of the processing gas in the ALE process has been described, but the process targeted is not limited to this. For example, the gas monitoring method of the present disclosure can also be applied to ALD (Atomic Layer Deposition). As described above, in the gas monitoring method of the present disclosure, the total flow rate of the processing gas can be monitored in real time in a manner including rising and falling. Therefore, in the case where gas supply / stop is short as in ALE and ALD, the gas monitoring method of the present disclosure is useful.

[0106] It should be considered that the embodiments disclosed herein are illustrative in all respects and not restrictive. The above embodiments can be omitted, replaced, and changed in various ways without departing from the appended claims and their gist.

Claims

1. A substrate processing method that uses a gas supplied to a chamber to process a substrate, the substrate processing method including the following steps: Step (a), setting a threshold value of the pressure of the gas to be controlled in a flow controller that measures the pressure of the gas supplied to the chamber to control the flow rate of the gas; Step (b), supplying a gas into the interior of the chamber; Step (c), measuring the pressure of the gas in the flow controller; Step (d), stopping the supply of the gas into the interior of the chamber; Step (e), calculating the time during which the pressure of the gas measured in Step (c) is equal to or greater than the threshold value; And Step (f), calculating the total flow rate of the gas supplied to the chamber based on the pressure of the gas measured in Step (c) and the time calculated in Step (e).

2. The substrate processing method according to claim 1, characterized in that: It further includes Step (g), in which, using the following formula (1), the pressure of the gas measured in Step (c) is converted into the flow rate of the gas, and the standardized flow rate of the gas is calculated, F = P × Fs(t) / Ps(t) ··· (1) where, F: the standardized flow rate of the gas, P: the pressure of the gas measured in Step (c), t: the elapsed time since the start of gas supply, Fs(t): the set value of the flow rate of the gas at time t, Ps(t): the set value of the pressure of the gas at time t.

3. The substrate processing method according to claim 2, characterized in that: In Step (f), the total flow rate of the gas is calculated by integrating the standardized flow rate of the gas in Step (g) with the time calculated in Step (e).

4. The substrate processing method according to any one of claims 1 to 3, characterized in that: The time calculated in Step (e) includes: When the pressure of the gas measured in Step (c) rises, the forward time before the pressure reaches the threshold value; and When the pressure of the gas measured in Step (c) drops, the backward time after the pressure reaches the threshold value, where, the forward time and the backward time are set in Step (a).

5. The substrate processing method according to any one of claims 1 to 3, characterized in that: The threshold value is a value determined based on the data of the gas flow rate measured by the flow controller and the data of the actual gas flow rate.

6. The substrate processing method according to claim 4, characterized in that: The forward time and the backward time are determined based on the data of the gas flow rate measured by the flow controller and the data of the actual gas flow rate.

7. The substrate processing method according to any one of claims 1 to 3, characterized in that: It further includes Step (h), in which, it is determined whether the total flow rate of the gas calculated in Step (f) is within the desired range of the flow rate.

8. The substrate processing method according to claim 7, characterized in that: When it is determined in the process (h) that the total flow rate of the gas calculated in the process (f) is within the desired range, the substrate processing is continued.

9. The substrate processing method according to claim 7, characterized in that: When it is determined in the process (h) that the total flow rate of the gas calculated in the process (f) is outside the desired range, feedback control is performed on the set value of the flow rate of the gas in the flow rate controller.

10. The substrate processing method according to any one of claims 1 to 3, characterized in that: When processing one substrate, the processes (a) to (f) are repeated, and the average of the total flow rates of the gas calculated in each process (f) is calculated.

11. The substrate processing method according to any one of claims 1 to 3, characterized in that: The rise time of the process (b) and / or the fall time of the process (d) are each 3 seconds or less.

12. The substrate processing method according to any one of claims 1 to 3, characterized in that: The substrate is processed by repeating the supply and stop of the gas.

13. The substrate processing method according to any one of claims 1 to 3, characterized in that: The substrate is processed by atomic layer etching and / or atomic layer deposition.

14. A substrate processing system that uses a gas to process a substrate, the substrate processing system comprising: A chamber having a gas supply port and a gas discharge port; A flow rate controller that measures the pressure of the gas supplied to the chamber to control the flow rate of the gas; and A control unit, Among them, The control unit controls the system to perform a process including the following processes: Process (a), setting a threshold value of the pressure of the gas to be controlled in the flow rate controller; Process (b), supplying gas to the inside of the chamber; Process (c), measuring the pressure of the gas in the flow rate controller; Process (d), stopping the supply of gas to the inside of the chamber; Process (e), calculating the time during which the pressure of the gas measured in the process (c) is equal to or higher than the threshold value; And Process (f), calculating the total flow rate of the gas supplied to the chamber based on the pressure of the gas measured in the process (c) and the time calculated in the process (e).

15. The substrate processing system according to claim 14, characterized in that: It further has a gas supply unit that supplies the gas to the inside of the chamber via the flow rate controller, The gas supply unit includes a board that collects data measured by the flow rate controller.

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