Gas supply system, substrate processing apparatus, and control method for gas supply system

Abstract

The present application provides a kind of gas supply system, substrate processing device and the control method of gas supply system, inhibit the reverse flow of purge gas to the upstream side of pipe.Gas supply system has: pipe, which is used for processing gas for substrate processing to flow through;Purge gas introduction pipe, which is connected with pipe and introduces purge gas to pipe;1st valve, which is arranged at the position of upstream side of pipe than the connecting point connected with purge gas introduction pipe;2nd valve, which is arranged at the position of upstream side of pipe than 1st valve;And control unit, in the case where processing gas is circulated to pipe, 1st valve and 2nd valve are maintained in open state, and in the case where the gas circulating in pipe is switched from processing gas to purge gas, 1st valve and 2nd valve are switched from open state to closed state.

Description

Technical Field

[0001] This disclosure relates to a gas supply system, a substrate processing apparatus, and a control method for the gas supply system. Background Technology

[0002] Patent Document 1 discloses a purge gas inlet pipe connected to a piping for the flow of processing gas used in substrate processing. When switching the gas flowing into the piping from processing gas to purge gas, a valve located on the upstream side of the piping is switched from an open state to a closed state.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2-50421 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] This disclosure provides a technique for suppressing the backflow of purge gas to the upstream side of the piping.

[0008] Solution for solving the problem

[0009] A gas supply system based on the present disclosure includes: a piping through which processing gas used for substrate processing flows; a purge gas inlet pipe connected to the piping and introducing purge gas into the piping; a first valve located upstream of the connection point of the piping and the purge gas inlet pipe; a second valve located upstream of the first valve on the piping; and a control unit that, when the processing gas flows into the piping, maintains the first valve and the second valve in an open state, and switches the first valve and the second valve from the open state to the closed state when the gas flowing in the piping is switched from the processing gas to the purge gas.

[0010] The effects of the invention

[0011] According to this disclosure, it has the effect of suppressing the backflow of purging gas to the upstream side of the piping. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating an example of a cross-section of a plasma processing apparatus according to an embodiment.

[0013] Figure 2 This is a diagram illustrating an example of the schematic structure of a gas supply system according to an embodiment.

[0014] Figure 3 This diagram illustrates the switching of gases in the implementation method.

[0015] Figure 4 This diagram illustrates the switching of gases in the implementation method.

[0016] Figure 5 This is a diagram illustrating an example of leak detection in an implementation method.

[0017] Figure 6 This is a diagram illustrating an example of leak detection in an implementation method. Detailed Implementation

[0018] Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings. Furthermore, in each drawing, the same or equivalent parts will be labeled with the same reference numerals.

[0019] Furthermore, in the substrate processing apparatus, when switching the gas flowing into the piping from processing gas to purge gas, leaks sometimes occur at the valve located upstream of the piping. If purge gas is introduced into the piping from the purge gas inlet pipe while the valve upstream of the piping is leaking, the introduced purge gas will flow backward through the valve towards the upstream side of the piping. This backflow of purge gas towards the upstream side of the piping is a major cause of purge gas mixing with the processing gas, which is undesirable. Therefore, it is desirable to suppress the backflow of purge gas towards the upstream side of the piping.

[0020] [Structure of the substrate processing device]

[0021] The structure of the substrate processing apparatus according to the embodiment will be described. A substrate processing apparatus is an apparatus for performing predetermined substrate processing on substrates such as wafers. In this embodiment, the case where the substrate processing apparatus is configured as a plasma processing apparatus 10 that performs processes such as plasma etching on a wafer W that serves as a substrate will be described as an example. Figure 1 This is a diagram illustrating an example of a cross-section of a plasma processing apparatus according to a schematic embodiment. Figure 1 The plasma processing apparatus 10 shown is a capacitively coupled parallel plate plasma etching apparatus. The plasma processing apparatus 10 has a generally cylindrical processing container 12.

[0022] A mounting stage 16 is provided within the processing container 12. The mounting stage 16 includes a support member 18 and a base 20. The upper surface of the support member 18 serves as a mounting surface for the object to be processed, which is to be plasma-processed. In this embodiment, the wafer W, which is to be plasma-etched, is mounted on the upper surface of the support member 18. The base 20 has a generally disk-shaped form, and its main portion is made of a conductive metal, such as aluminum. The base 20 forms the lower electrode. The base 20 is supported by a support portion 14. The support portion 14 is a cylindrical member extending from the bottom of the processing container 12.

[0023] A first high-frequency power supply HFS is electrically connected to base station 20 via matching adapter MU1. The first high-frequency power supply HFS is a power source for generating high-frequency power for plasma generation, producing high-frequency power with a frequency of 27MHz to 100MHz, and in one example, 40MHz. Matching adapter MU1 has circuitry for matching the output impedance of the first high-frequency power supply HFS with the input impedance of the load side (base station 20 side).

[0024] Additionally, a second high-frequency power supply LFS is electrically connected to the base station 20 via a matching converter MU2. The second high-frequency power supply LFS generates high-frequency power (high-frequency bias power) for attracting ions to the wafer W, and supplies this high-frequency bias power to the base station 20. The frequency of the high-frequency bias power is in the range of 400 kHz to 13.56 MHz, and in one example, it is 3 MHz. The matching converter MU2 has circuitry for matching the output impedance of the second high-frequency power supply LFS with the input impedance on the load side (base station 20 side).

[0025] A support member 18 is provided on the base 20. The support member 18 is, for example, an electrostatic chuck. The support member 18 uses electrostatic forces such as Coulomb force to attract and hold the wafer W. The support member 18 has an electrode E1 for electrostatic attraction within its ceramic body. A DC power supply 22 is electrically connected to the electrode E1 via a switch SW1. In addition, a heater may be provided on the support member 18 to control the temperature of the wafer W.

[0026] A focusing ring FR is provided on the upper surface of the base 20 and around the support member 18. The focusing ring FR is provided to improve the uniformity of the plasma treatment. The focusing ring FR is made of a material appropriately selected according to the plasma treatment to be performed, for example, it may be made of silicon or quartz.

[0027] A refrigerant flow path 24 is formed inside the base 20. A cooling unit located outside the processing container 12 supplies refrigerant to the refrigerant flow path 24 via pipe 26a. The refrigerant supplied to the refrigerant flow path 24 returns to the cooling unit via pipe 26b.

[0028] An upper electrode 30, which also serves as a nozzle for ejecting gas toward the wafer W, is provided within the processing container 12. The upper electrode 30 is positioned above the stage 16 and opposite the base 20, with the base 20 and the upper electrode 30 arranged substantially parallel to each other. The space between the upper electrode 30 and the lower electrode LE forms a processing space S for generating plasma for plasma processing of the wafer W.

[0029] The upper electrode 30 is supported on the upper part of the processing container 12 by means of an insulating shielding member 32. The upper electrode 30 may include an electrode plate 34 and an electrode support 36. The electrode plate 34 faces the processing space S. A plurality of gas ejection holes 34a are provided on the electrode plate 34.

[0030] The electrode support 36 is made of a conductive material such as aluminum, supporting the electrode plate 34 for easy mounting and dismounting. The electrode support 36 may also have a water-cooling structure. Inside the electrode support 36 is a gas diffusion chamber 37 formed by a circular plate-shaped space. Extending downward from the gas diffusion chamber 37 are multiple gas flow holes 36b, each communicating with a gas ejection hole 34a.

[0031] The plasma processing apparatus 10 is provided with a gas supply source 40 for supplying various gases used in plasma processing. Additionally, a gas supply system 110 is connected to the electrode support 36 to supply the gas supplied from the gas supply source 40 to the gas diffusion chamber 37. Details of the gas supply system 110 will be described later.

[0032] The gas supplied to the gas diffusion chamber 37 is ejected into the processing space S through the gas flow port 36b and the gas ejection port 34a. The plasma processing apparatus 10 can control the flow rate of the processing gas ejected from the gas ejection port 34a of the gas diffusion chamber 37 into the processing space S by controlling the gas supply source 40 and the gas supply system 110.

[0033] On the bottom side of the processing container 12, an exhaust plate 48 is provided between the support portion 14 and the inner wall of the processing container 12. The exhaust plate 48 is constructed, for example, by coating aluminum with a ceramic such as Y2O3. An exhaust port 12e is provided below the exhaust plate 48 in the processing container 12. An exhaust device 50 is connected to the exhaust port 12e via an exhaust pipe 52. The exhaust device 50 has a vacuum pump such as a turbomolecular pump, which can reduce the pressure inside the processing container 12 to the desired vacuum level. Furthermore, the processing container 12 has a wafer W feed / outlet 12g on its side wall. The feed / outlet 12g can be opened and closed by a gate valve 54.

[0034] The operation of the plasma processing apparatus 10, configured as described above, is uniformly controlled by the control unit 100. The control unit 100, for example, is a computer, which controls each part of the plasma processing apparatus 10. The operation of the plasma processing apparatus 10 is uniformly controlled by the control unit 100.

[0035] The control unit 100 has a CPU, and also has a process controller 101 for controlling various parts of the plasma processing apparatus 10, a user interface 102, and a storage unit 103.

[0036] The user interface 102 consists of a keyboard for process managers to input commands for managing the plasma processing device 10, a display that visually shows the operating status of the plasma processing device 10, and the like.

[0037] The storage unit 103 stores control programs (software) for implementing various processes performed by the plasma processing apparatus 10 under the control of the process controller 101, as well as processes containing processing condition data. Furthermore, the process controller 101 retrieves and executes any process from the storage unit 103 based on instructions from the user interface 102, thereby enabling the plasma processing apparatus 10 to perform the desired processing under the control of the process controller 101. For example, the process controller 101 controls various parts of the plasma processing apparatus 10 to execute the control method of the gas supply system 110 described later. Additionally, the control programs, processing condition data, and other processes can also utilize the state of the control programs, processing condition data, and other processes stored on computer-readable computer storage media (e.g., hard disks, CDs, floppy disks, semiconductor memories, etc.). Furthermore, the control programs, processing condition data, and other processes can be transmitted from other devices, for example, via dedicated lines, and used online at any time.

[0038] Next, the structure of the gas supply system 110 of the embodiment will be described. Figure 2 This is a diagram illustrating an example of the schematic structure of a gas supply system according to an embodiment.

[0039] The gas supply source 40 has a gas source group that includes multiple gas sources used in plasma processing such as plasma etching. The gas supply source 40 has valves, flow controllers, etc. (not shown) at each of the multiple gas sources in the gas source group, and supplies a processing gas, either one type or a mixture of multiple gases, depending on the plasma processing requirements.

[0040] The gas supply system 110 supplies the processing gas supplied from the gas supply source 40 to the gas diffusion chamber 37.

[0041] A gas supply pipe 111 is connected to the gas supply source 40 as a conduit for supplying the processing gas to the gas diffusion chamber 37. The gas supply source 40 supplies a processing gas, consisting of one type or a mixture of multiple gases, to the gas supply pipe 111. For example, the processing gas is a CF-type gas, SiCl4, BCl4, SO2, or a mixture thereof. The gas supply pipe 111 is connected to the gas diffusion chamber 37.

[0042] The gas supply pipe 111 is equipped with a flow controller 112, which can adjust the flow rate of the processing gas supplied to the gas diffusion chamber 37, midway through the gas supply pipe 111. The processing gas supplied to the gas supply pipe 111 reaches the gas diffusion chamber 37 after the flow rate is adjusted by the flow controller 112.

[0043] Additionally, a purge gas inlet pipe 121 is connected to the gas supply pipe 111 upstream of the flow controller 112. The purge gas inlet pipe 121 is connected to a purge gas supply source (not shown), and purge gas supplied from the purge gas supply source is introduced into the gas supply pipe 111. For example, the purge gas inlet pipe 121 may introduce an inactive gas such as N2 as the purge gas into the gas supply pipe 111. By introducing purge gas into the gas supply pipe 111, the processing gas remaining in the gas supply pipe 111 and the flow controller 112 is purged. The purge gas inlet pipe 121 is equipped with a valve 122 that switches the opening and closing state of the purge gas inlet pipe 121.

[0044] A valve 131 is provided on the gas supply pipe 111 upstream of the connection point 111a of the purge gas inlet pipe 121. Additionally, a valve 132 is provided on the gas supply pipe 111 upstream of valve 131. Both valves 131 and 132 are pneumatic valves that switch between a self-closing and open state using air. A solenoid valve 141 is connected to valve 131 via the air supply pipe 131a. A branch pipe 132a branching from the air supply pipe 131a is connected to valve 132. The solenoid valve 141 is connected to an air supply source (not shown), supplying air to valve 131 via the air supply pipe 131a, and supplying air flowing within the air supply pipe 131a to valve 132 via the branch pipe 132a.

[0045] Branch pipe 132a is equipped with a state-switching valve 142 that can selectively switch between a supply-allowed state and a cut-off state. In the supply-allowed state, state-switching valve 142 allows air to be supplied from solenoid valve 141 to valve 132 via branch pipe 132a. Conversely, in the cut-off state, state-switching valve 142 cuts off the air supply from solenoid valve 141 to valve 132 via branch pipe 132a. By switching state-switching valve 142 to the cut-off state, the air supply to valve 132 is cut off, thus valve 132 remains closed. State-switching valve 142 is connected to a manual valve 143 that can supply air and can be manually switched between open and closed states. Air is supplied from manual valve 143, switching from the cut-off state to the supply-allowed state. Additionally, state-switching valve 142 switches from the supply-allowed state to the cut-off state by stopping the air supply from manual valve 143. State-switching valve 142 is essentially maintained in the supply-allowed state, but switches from the supply-allowed state to the cut-off state when leakage detection of valve 132 is performed.

[0046] In addition, a valve 133 is provided on the gas supply pipe 111 downstream of the flow controller 112 to switch the opening and closing state of the gas supply pipe 111. The valve 133 is always kept in the open state during the operation of the plasma processing device 10.

[0047] Furthermore, in the plasma processing apparatus 10, when switching the gas flowing into the gas supply pipe 111 from processing gas to purge gas, the valve 131 located upstream of the connection point 111a of the purge gas inlet pipe 121 in the gas supply pipe 111 is switched from an open state to a closed state. At this time, leakage may sometimes occur in the valve 131. If purge gas is introduced from the purge gas inlet pipe 121 into the gas supply pipe 111 while the valve 131 is leaking, the introduced purge gas may flow backward through the valve 131 to the upstream side of the gas supply pipe 111. This backward flow of purge gas to the upstream side of the gas supply pipe 111 is a major cause of purge gas mixing with the processing gas, and is therefore undesirable.

[0048] Therefore, the plasma processing device 10 provides a valve 132 upstream of the valve 131 in the gas supply pipe 111. When the gas flowing in the gas supply pipe 111 is switched from processing gas to purging gas, both valve 131 and valve 132 are switched from the open state to the closed state.

[0049] Figure 3 as well as Figure 4 This diagram illustrates the switching of gases in the implementation method. Figure 3 The diagram shows the flow of processing gas into the gas supply pipe 111. Figure 4This illustrates the case where purge gas flows into the gas supply pipe 111. When process gas flows into the gas supply pipe 111, as... Figure 3 As shown, the control unit 100 maintains valves 131 and 132 in the open state. Specifically, while maintaining valve 122, which is located in the purge gas inlet pipe 121, in the closed state, the control unit 100 maintains valves 131 and 132 in the open state by supplying air from the solenoid valve 141. As a result, the processing gas flowing in the gas supply pipe 111 is supplied to the gas diffusion chamber 37.

[0050] In the case where the gas flowing in the gas supply pipe 111 is switched from processing gas to purging gas, such as Figure 4 As shown, the control unit 100 switches valves 131 and 132 from the open state to the closed state. Specifically, the control unit 100 switches valves 131 and 132 from the open state to the closed state by stopping the supply of air from the solenoid valve 141. Furthermore, after switching valves 131 and 132 from the open state to the closed state, the control unit 100 controls the switching of valve 122, located in the purge gas inlet pipe 121, from the closed state to the open state. As a result, purge gas is introduced from the purge gas inlet pipe 121 into the gas supply pipe 111.

[0051] Thus, when the plasma processing apparatus 10 switches the gas flowing in the gas supply pipe 111 from processing gas to purge gas, it switches both valves 131 and 132 from the open state to the closed state, thereby cutting off the upstream side of the gas supply pipe 111 using the double valves. As a result, the backflow of purge gas to the upstream side of the gas supply pipe 111 can be suppressed.

[0052] Furthermore, if leaks occur in valves 131 and 132 when switching the gas flowing in the gas supply pipe 111 from processing gas to purge gas, backflow of purge gas to the upstream side of the gas supply pipe 111 may occur. Therefore, it is preferable to perform leak detection on valves 131 and 132 separately. The leak detection of valves 131 and 132 will be explained below.

[0053] Figure 5 as well as Figure 6 This is a diagram illustrating an example of leak detection in an implementation method. Figure 5 The following shows the situation where leakage detection is performed on valve 131. Figure 6 The following shows the situation where leakage detection is performed on valve 132.

[0054] In the case of leak detection of valve 131, firstly, as Figure 5As shown, after maintaining valves 131 and 132 in an open state for a predetermined period, the control unit 100 switches valves 131 and 132 from the open state to the closed state. Specifically, after maintaining valves 131 and 132 in an open state for a predetermined period by supplying air from solenoid valve 141, the control unit 100 switches valves 131 and 132 from the open state to the closed state by stopping the supply of air from solenoid valve 141. This seals the portion between valves 131 and 132 in the gas supply pipe 111 with processing gas. With processing gas sealed between valves 131 and 132, the control unit 100 uses the exhaust device 50 to perform a vacuum evacuation and detects leakage in valve 131 by referring to the pressure measurement results obtained using a pressure gauge (not shown).

[0055] When the leakage detection of valve 131 ends, as follows Figure 6 As shown, the state switching valve 142 is switched from the supply-allowed state to the cut-off state, and a leak test of valve 132 is started. When performing leak detection on valve 132, the control unit 100 first switches valve 131 from the closed state to the open state. Specifically, the control unit 100 switches valve 131 from the closed state to the open state by supplying air from solenoid valve 141. Here, since the state switching valve 142 is switched to the cut-off state, the air supply from solenoid valve 141 to valve 132 via branch pipe 132a is cut off. By cutting off the air supply to valve 132, valve 132 remains closed, and only valve 131 switches from the closed state to the open state. As a result, the portion of the processing gas sealed between valve 131 and valve 132 in the gas supply pipe 111 is released to the downstream side of valve 131. Afterwards, the control unit 100 performs vacuuming using the exhaust device 50 and performs leak detection on valve 132 by referring to the pressure measurement results obtained using a pressure gauge (not shown).

[0056] In the plasma processing apparatus 10, the air supply to the valve 132 is cut off by the state switching valve 142, thereby enabling the opening and closing state of the valve 131 to be switched independently of the valve 132, and enabling leakage detection of the valve 131 and the valve 132 to be performed separately.

[0057] As described above, the gas supply system 110 of this embodiment includes a gas supply pipe 111, a purge gas inlet pipe 121, valves 131 and 132, and a control unit 100. The gas supply pipe 111 supplies processing gas used for substrate processing. The purge gas inlet pipe 121 is connected to the gas supply pipe 111 and introduces purge gas into the gas supply pipe 111. Valve 131 is located upstream of the connection point 111a of the gas supply pipe 111 and the purge gas inlet pipe 121. Valve 132 is located upstream of the gas supply pipe 111 and the valve 131. The control unit 100 maintains valves 131 and 132 in an open state when processing gas flows into the gas supply pipe 111. Furthermore, the control unit 100 switches valves 131 and 132 from the open state to the closed state when switching the gas flowing in the gas supply pipe 111 from processing gas to purge gas. Therefore, the gas supply system 110 can suppress the backflow of purge gas to the upstream side of the gas supply pipe 111.

[0058] Furthermore, in the gas supply system 110, valves 131 and 132 are pneumatic valves that switch from a closed state to an open state using the supplied air. The gas supply system 110 also includes a solenoid valve 141, which supplies air to valve 131 via an air supply pipe 131a, and supplies air flowing within the air supply pipe 131a to valve 132 via a branch pipe 132a branching off from the air supply pipe 131a. Moreover, when processing gas flows into the gas supply pipe 111, the control unit 100 maintains valves 131 and 132 in an open state by supplying air from the solenoid valve 141. Additionally, when switching the gas flowing within the gas supply pipe 111 from processing gas to purge gas, the control unit 100 switches valves 131 and 132 from an open state to a closed state by stopping the supply of air from the solenoid valve 141. Therefore, since the gas supply system 110 can cut off the upstream side of the gas supply pipe 111 by using a dual pneumatic valve, it can suppress the backflow of purge gas to the upstream side of the gas supply pipe 111.

[0059] In addition, the gas supply system 110 also includes a state switching valve 142, which is located on the branch pipe 132a and can selectively switch between a supply-allowed state and a cut-off state. In the supply-allowed state, the state switching valve 142 allows air to be supplied from the solenoid valve 141 to the valve 132 via the branch pipe 132a, and in the cut-off state, it cuts off the air supply from the solenoid valve 141 to the valve 132 via the branch pipe 132a. Thus, the gas supply system 110 can independently switch the opening and closing state of the valve 131, and can independently detect leaks in both the valve 131 and the valve 132.

[0060] Furthermore, the embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The above embodiments may also be omitted, substituted, or modified in various ways without departing from the appended claims and their spirit.

Claims

1. A gas supply system, wherein the gas supply system has: a first gas supply pipe connected between a process gas source and a substrate processing chamber, the first gas supply pipe having an intermediate connection point; a second gas supply pipe connected between a purge gas source and the intermediate connection point; a first valve provided on the first gas supply pipe on an upstream side of the intermediate connection point; a second valve provided on the first gas supply pipe on an upstream side of the first valve; a first air supply pipe connected between an air source and the first valve, the first air supply pipe having a branch connection point; a second air supply pipe connected between the branch connection point and the second valve; a solenoid valve provided on the first air supply pipe on an upstream side of the branch connection point; and a control section that controls the first valve and the second valve to open the first valve and the second valve in a first mode for supplying a process gas from the process gas source to the substrate processing chamber, and to close the first valve and the second valve in a second mode for supplying a purge gas from the purge gas source to the substrate processing chamber; the first valve and the second valve are pneumatic valves, the control section is configured to control the solenoid valve to open the solenoid valve in the first mode, and to close the solenoid valve in the second mode.

2. The gas supply system according to claim 1, wherein the control section is configured to control the first valve and the second valve to open the first valve and the second valve simultaneously in the first mode, and to close the first valve and the second valve simultaneously in the second mode.

3. The gas supply system according to claim 1, wherein the gas supply system further has a shut-off valve provided on the second air supply pipe, and the shut-off valve allows shut-off of the supply of air from the air source to the second valve.

4. The gas supply system according to claim 3, wherein the shut-off valve is a pneumatic valve.

5. The gas supply system according to claim 3 or 4, wherein the gas supply system further has: a third air supply pipe connected to the shut-off valve; and a manual valve provided on the third air supply pipe.

6. A gas supply system, wherein the gas supply system has: a pipe through which a process gas used for substrate processing flows; a purge gas introduction pipe connected to the pipe and introducing a purge gas to the pipe; a first valve provided at a position on the pipe on an upstream side from a connection point to which the purge gas introduction pipe is connected; a second valve provided at a position on the pipe on an upstream side from the first valve; and a control section that, in a case where the process gas is caused to flow through the pipe, maintains the first valve and the second valve in an open state, and, in a case where a gas flowing through the pipe is switched from the process gas to the purge gas, switches the first valve and the second valve from the open state to a closed state, wherein the first valve and the second valve are pneumatic valves that are switched from the closed state to the open state by supplied air, the control section is configured to control the solenoid valve to open the solenoid valve in the first mode, and to close the solenoid valve in the second mode. The gas supply system further has a solenoid valve that supplies air to the first valve via an air supply pipe and supplies the air flowing in the air supply pipe to the second valve via a branch pipe branched from the air supply pipe, The control section maintains the first valve and the second valve in an open state by supplying air from the solenoid valve when the processing gas is circulated to the pipe, and switches the first valve and the second valve from the open state to a closed state by stopping the supply of air from the solenoid valve when the gas circulated in the pipe is switched from the processing gas to the purge gas.

7. A substrate processing apparatus characterized by comprising: The substrate processing apparatus has the gas supply system according to any one of claims 1 to 6.

8. A control method of a gas supply system, which is a control method of a gas supply system having: a first gas supply pipe connected between a processing gas source and a substrate processing chamber, the first gas supply pipe having an intermediate connection point; a second gas supply pipe connected between a purge gas source and the intermediate connection point; a first valve provided on the first gas supply pipe on an upstream side of the intermediate connection point; a second valve provided on the first gas supply pipe on an upstream side of the first valve; a first air supply pipe connected between an air source and the first valve, the first air supply pipe having a branch connection point; a second air supply pipe connected between the branch connection point and the second valve; and a solenoid valve provided on the first air supply pipe on an upstream side of the branch connection point, the first valve and the second valve are pneumatic valves, in the control method of the gas supply system, the first valve and the second valve are opened in a first mode for supplying a processing gas from the processing gas source to the substrate processing chamber, and the first valve and the second valve are closed in a second mode for supplying a purge gas from the purge gas source to the substrate processing chamber, the solenoid valve is opened in the first mode, and the solenoid valve is closed in the second mode.

9. A control method of a gas supply system, which is a control method of a gas supply system having: a pipe through which a processing gas used for substrate processing is circulated; a purge gas introduction pipe connected to the pipe and introducing a purge gas to the pipe; a first valve provided at a position of the pipe on an upstream side from a connection point connected to the purge gas introduction pipe; and a second valve provided at a position of the pipe on an upstream side from the first valve, in the control method of the gas supply system, the first valve and the second valve are maintained in an open state when the processing gas is circulated to the pipe, and the first valve and the second valve are switched from the open state to a closed state when the gas circulated in the pipe is switched from the processing gas to the purge gas, wherein, the first valve and the second valve are pneumatic valves that are switched from the closed state to the open state by supplied air, the first valve and the second valve are pneumatic valves that are switched from the closed state to the open state by supplied air, The gas supply system further has a solenoid valve that supplies air to the first valve via an air supply pipe and supplies the air flowing in the air supply pipe to the second valve via a branch pipe branched from the air supply pipe, In the control method of the gas supply system, in a case where the process gas is circulated in the pipe, the first valve and the second valve are maintained in an open state by supplying air from the solenoid valve, and in a case where the gas circulating in the pipe is switched from the process gas to the purge gas, the first valve and the second valve are switched from the open state to a closed state by stopping the supply of air from the solenoid valve.

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