Substrate processing apparatus and substrate processing method

Abstract

This substrate processing apparatus is provided with: a container; an opening part that is provided in the container and through which a substrate passes; a shutter that opens and closes the opening part; a substrate holding part that holds the substrate inside the container; an exhaust duct for exhausting gas to the outside from the inside of the container; an exhaust damper that adjusts the exhaust amount of the exhaust duct; an opening sensor that detects the opening of the exhaust damper; and a control circuit that controls the opening of the exhaust damper in each of an opening period in which the shutter opens the opening part, and a closed period in which the shutter closes the opening part. The control circuit performs, in the opening period, offset control for fixing the opening of the exhaust damper to a value that is offset by a set amount from a detection value of the opening sensor in the closed period immediately before the opening period.

Description

Substrate processing apparatus and substrate processing method

[0001] The present disclosure relates to a substrate processing apparatus and a substrate processing method.

[0002] The substrate processing apparatus described in Patent Document 1 includes a damper. The damper is a mechanism for adjusting the amount of exhaust. A control device adjusts the amount of exhaust by controlling the opening of the damper. The control device normally performs feedback control of the opening of the damper so as to maintain the internal pressure of the chamber within a specified range. When a predetermined event occurs, the control device switches the control of the opening of the damper from feedback control to non-feedback control.

[0003] Japanese Patent Application Publication No. 2016-21528

[0004] One aspect of the present disclosure provides a technique for suppressing pressure fluctuations inside a container.

[0005] a control circuit configured to control the opening of the exhaust damper during an open period in which the shutter opens the opening and a closed period in which the shutter closes the opening, the control circuit performing offset control to fix the opening of the exhaust damper to a value offset by a set amount from a detection value of the opening sensor during the closed period immediately before the open period.

[0006] According to one aspect of the present disclosure, pressure fluctuations inside a container can be suppressed.

[0007] Fig. 1 is a cross-sectional view showing a substrate processing apparatus according to an embodiment. Fig. 2 is a flowchart showing a substrate processing method according to an embodiment. Fig. 3 is a flowchart showing an example of a method for controlling the opening degree of an exhaust damper. Fig. 4 is a diagram showing an example of changes over time in the pressure inside a container and the opening degree of an exhaust damper.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0009] A substrate processing apparatus 1 according to one embodiment will be described with reference to Fig. 1. The substrate processing apparatus 1 includes, for example, a container 10, an opening 11, a shutter 12, a substrate holder 20, a liquid supply unit 30, a heating unit 40, a cup 50, and a control circuit 90.

[0010] The container 10 accommodates a substrate W. An opening 11 through which the substrate W passes is provided in the sidewall of the container 10. A shutter 12 opens and closes the opening 11 under the control of a control circuit 90. An FFU (Fan Filter Unit) 13 is provided on the ceiling of the container 10. The FFU 13 forms a downflow inside the container 10.

[0011] The substrate W is a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer, or a glass substrate. The substrate W is carried from the outside to the inside of the container 10 through the opening 11 by the transport device 2. After being treated with the treatment liquid, the substrate W is carried from the inside of the container 10 to the outside through the opening 11 by the transport device 2.

[0012] The substrate holding unit 20 holds the substrate W inside the container 10. The substrate holding unit 20 holds the substrate W horizontally, for example. The substrate holding unit 20 is, for example, a vacuum chuck or a mechanical chuck. The rotation drive unit 25 rotates the substrate holding unit 20 around a vertical rotation axis 21. The rotation drive unit 25 includes a reduction mechanism, a motor, etc.

[0013] The liquid supply unit 30 supplies a processing liquid to the substrate W held by the substrate holding unit 20. The liquid supply unit 30 has a nozzle 31. The nozzle 31 is arranged above the substrate W held by the substrate holding unit 20, and ejects the processing liquid toward the upper surface of the substrate W. The number of nozzles 31 is not particularly limited, and a nozzle 31 may be provided for each type of processing liquid. One nozzle 31 may eject multiple types of processing liquid in sequence. The nozzle 31 may be a two-fluid nozzle, and the processing liquid may be ejected in the form of a mist using gas pressure.

[0014] The processing liquid includes a chemical liquid and a rinse liquid that removes the chemical liquid from the substrate W. The chemical liquid is, for example, SC1 (a mixture of ammonia water and hydrogen peroxide solution), SPM (a mixture of sulfuric acid and hydrogen peroxide solution), or DHF (dilute hydrofluoric acid). The rinse liquid is, for example, pure water such as DIW (deionized water). The processing liquid may include an organic solvent such as IPA (isopropyl alcohol) that replaces the rinse liquid.

[0015] The liquid supply unit 30 has a supply line 32 that supplies the processing liquid to the nozzle 31, and various devices provided along the supply line 32. The various devices include, for example, an on-off valve 33, a flow meter 34, and a flow rate regulator 35. The on-off valve 33 opens and closes the flow path of the processing liquid. The flow meter 34 measures the flow rate of the processing liquid. The flow rate regulator 35 regulates the flow rate of the processing liquid. Various devices are provided for each processing liquid.

[0016] The liquid supply unit 30 has a nozzle moving unit 36 ​​that moves the nozzle 31. The nozzle moving unit 36 ​​has, for example, a swivel arm, a swivel mechanism, and an elevator mechanism. The nozzle 31 is provided at one end of the swivel arm, and a swivel shaft is provided at the other end of the swivel arm. The swivel arm is provided horizontally, and the swivel shaft is provided vertically. The swivel mechanism moves the nozzle 31 horizontally by rotating the swivel arm around the swivel shaft. The elevator mechanism raises and lowers the nozzle 31 by raising and lowering the swivel arm. The swivel mechanism and the elevator mechanism each include an actuator such as a motor or a cylinder. The configuration of the nozzle moving unit 36 ​​is not particularly limited.

[0017] The heating unit 40 heats the lower surface of the substrate W held by the substrate holding unit 20. The heating unit 40 heats the peripheral portion of the lower surface of the substrate W by supplying preheated gas to the peripheral portion of the lower surface of the substrate W. The heating unit 40 includes, for example, a heater 41, an on-off valve 42, and a flow rate regulator 43. The heater 41 heats the gas. The on-off valve 42 opens and closes the gas flow path. The flow rate regulator 43 regulates the flow rate of the gas.

[0018] The cup 50 surrounds the substrate W held by the substrate holding part 20. The cup 50 receives the processing liquid splashed from the periphery of the substrate W. In this embodiment, the cup 50 does not rotate together with the substrate holding part 20, but it may rotate together with the substrate holding part 20. A drain pipe 51 and an exhaust pipe 52 are provided at the bottom of the cup 50. The drain pipe 51 discharges liquid accumulated inside the cup 50. The exhaust pipe 52 discharges gas accumulated inside the cup 50.

[0019] The control circuit 90 is, for example, a computer, and includes an arithmetic unit 91 such as a CPU (Central Processing Unit) and a storage unit 92 such as a memory. The storage unit 92 stores programs that control various processes executed in the substrate processing apparatus 1. The control circuit 90 controls the operation of the substrate processing apparatus 1 by causing the arithmetic unit 91 to execute the programs stored in the storage unit 92.

[0020] The control circuit 90 includes electronic circuits such as a CPU, an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit), and performs the various control operations described in this specification by executing instruction codes stored in memory or by being a circuit designed for a specific application.

[0021] Next, a substrate processing method according to one embodiment will be described with reference to Fig. 2. First, the shutter 12 opens the opening 11 (step S101). Next, the transport device 2 loads the substrate W from the outside to the inside of the container 10 (step S102). At this time, the substrate holder 20 holds the substrate W horizontally. Thereafter, when the transport device 2 exits from the inside of the container 10 to the outside, the shutter 12 closes the opening 11 (step S103).

[0022] Next, the rotation drive unit 25 rotates the substrate W together with the substrate holding unit 20 (step S104). Next, the liquid supply unit 30 supplies the processing liquid to the substrate W (step S105). At this time, the heating unit 40 may supply preheated gas to the substrate W. Thereafter, the liquid supply unit 30 stops supplying the processing liquid, and the rotation drive unit 25 rotates the substrate W together with the substrate holding unit 20 to dry the substrate W (step S106). Thereafter, the rotation drive unit 25 stops rotating the substrate W.

[0023] Next, the shutter 12 opens the opening 11 again (step S107). Next, the transport device 2 (not shown) enters the container 10 from the outside to the inside and receives the substrate W from the substrate holder 20. The substrate holder 20 releases its hold on the substrate W in advance. Subsequently, the transport device 2 transports the substrate W from the inside of the container 10 to the outside (step S108). Thereafter, the shutter 12 closes the opening 11 again (step S109).

[0024] 1 again, the exhaust system of the substrate processing apparatus 1 will be described. The substrate processing apparatus 1 includes an exhaust duct 70 and a switching unit 71. The exhaust duct 70 exhausts gas from the inside of the container 10 to the outside. The switching unit 71 switches the destination of the gas flowing through the exhaust duct 70 depending on the type of gas flowing through the exhaust duct 70. For example, the switching unit 71 switches the destination of the gas flowing through the exhaust duct 70 depending on the type of processing liquid supplied to the substrate W by the liquid supply unit 30.

[0025] The switching unit 71 sends gas to multiple exhaust sources 73 via multiple individual pipes 72. One exhaust source 73 sucks in alkaline or neutral gas, and another exhaust source 73 sucks in acidic gas. Alternatively, one exhaust source 73 may suck in alkaline gas, and another exhaust source 73 may suck in acidic or neutral gas. By switching the gas destination depending on the type of gas, the gas can be easily rendered harmless. The exhaust source 73 includes, for example, a suction pump. An ejector can also be used instead of the suction pump.

[0026] The switching unit 71 includes, for example, a switching valve 71a. The switching valve 71a is provided for each individual pipe 72 and is switchable between a state in which the individual pipe 72 communicates with the exhaust duct 70 and a state in which the individual pipe 72 is disconnected from the exhaust duct 70. When disconnecting the individual pipe 72 from the exhaust duct 70, the switching valve 71a may introduce outside air into the individual pipe 72. By introducing outside air into the individual pipe 72 that is disconnected from the exhaust duct 70, the suction amounts of all exhaust sources 73 can be stabilized regardless of the destination of the gas flowing through the exhaust duct 70.

[0027] The exhaust duct 70 and the switching unit 71 are provided in each of the plurality of substrate processing apparatuses 1. In contrast, the individual pipes 72 and exhaust sources 73 are shared by the plurality of substrate processing apparatuses 1. The switching valve 71 a introduces outside air into the individual pipes 72 that are isolated from the exhaust duct 70, thereby stabilizing the loads of all exhaust sources 73 and stabilizing the pressure inside all containers 10, regardless of the destination of the gas flowing through the exhaust duct 70.

[0028] In addition to the exhaust duct 70, the substrate processing apparatus 1 is equipped with an exhaust damper 81 and an opening sensor 82. The exhaust damper 81 adjusts the amount of exhaust air from the exhaust duct 70. The opening sensor 82 detects the opening degree of the exhaust damper 81. The opening degree sensor 82 transmits the detected value of the opening degree to a control circuit 90. The control circuit 90 controls the opening degree of the exhaust damper 81 during both an open period when the shutter 12 opens the opening 11 and a closed period when the shutter 12 closes the opening 11. The greater the opening degree of the exhaust damper 81, the greater the amount of exhaust air from the exhaust duct 70.

[0029] Next, an example of controlling the opening degree of the exhaust damper 81 will be described with reference to FIG. 3 . The control circuit 90 checks whether the current period is a closed period (step S201). If the current period is a closed period (step S201, YES), the control circuit 90 feedback-controls the opening degree of the exhaust damper 81 so that the detection value of the pressure sensor 83 becomes a set value (step S202). The pressure sensor 83 detects the pressure inside the container 10. The pressure sensor 83 transmits the detected pressure value to the control circuit 90. During the closed period, the opening degree of the exhaust damper 81 can be varied to maintain the pressure inside the container 10 at the set value.

[0030] If the current period is not a closed period but an open period (step S201, NO), the pressure inside the container 10 attempts to become equal to the pressure outside the container 10 (for example, the transfer chamber to which the transfer device 2 transfers the substrate W). The pressure outside the container 10 is set, for example, to be lower than the pressure inside the container 10. A gas flow can be formed from the inside of the container 10 to the outside through the opening 11, and particles can be prevented from entering the inside of the container 10 from the outside. Therefore, the inside of the container 10 can be kept clean. Note that the pressure outside the container 10 may be set higher than the pressure inside the container 10.

[0031] If the current period is an open period (step S201, NO), if there is a pressure difference between the outside and the inside of the container 10, the pressure inside the container 10 will attempt to become equal to the pressure outside the container 10. In this case, the control circuit 90 performs control to fix the opening degree of the exhaust damper 81 (step S203). The control circuit 90 fixes the opening degree of the exhaust damper 81 to the detection value detected by the opening degree sensor 82 during the closed period immediately before the open period (preferably at the end of the closed period), for example.

[0032] As will be described in detail later, during the closed period, the control circuit 90 may perform control to fix the opening of the exhaust damper 81 to a value that is offset by a set amount from the detection value detected by the opening sensor 82 during the closed period immediately preceding the open period (preferably at the end of the closed period). This control will be referred to as offset control hereinafter. In either case, if the current period is the open period (NO in step S201), the control circuit 90 performs control to fix the opening of the exhaust damper 81.

[0033] Next, referring mainly to FIG. 4 , an example of the change over time in the pressure inside the container 10 and the opening degree of the exhaust damper 81 will be described. In FIG. 4 , the periods indicated by the dotted pattern are open periods. Also in FIG. 4 , dashed lines L1 and L3 represent data when offset control is not performed, and solid lines L2 and L4 represent data when offset control is performed. Offset control is performed, for example, on the second or subsequent lots. Offset control does not need to be performed on the first lot. However, offset control indicated by arrow A2 in FIG. 4 may be performed on the first lot, as described below. One lot consists of, for example, n substrates W stored in one cassette. n may be a natural number equal to or greater than 2 and is not particularly limited, but is, for example, 25.

[0034] The shutter 12 closes the opening 11 until the first (first) substrate W of each lot is transported in front of the opening 11 of the container 10. At this time, there is no substrate W inside the container 10, and the substrate holder 20 is not holding any substrate W. Thereafter, when the shutter 12 opens the opening 11, the transport device 2 transports the substrate W from outside to inside the container 10. Next, when the substrate holder 20 holds the substrate W horizontally and the transport device 2 retreats from inside the container 10 to the outside, the shutter 12 closes the opening 11.

[0035] Next, the liquid supply unit 30 supplies the processing liquid to the substrate W. At this time, the heating unit 40 may supply preheated gas to the substrate W. After the substrate W is dried, the shutter 12 opens the opening 11. Thereafter, the transport device 2 carries out the substrate W, and then carries in another substrate W. Next, the substrate holder 20 holds the substrate W horizontally, and when the transport device 2 retreats from the inside to the outside of the container 10, the shutter 12 closes the opening 11. Thereafter, the same operation is repeated.

[0036] After the last (nth) substrate W of each lot is transferred from inside to outside the container 10, the shutter 12 closes the opening 11. At this time, there are no substrates W inside the container 10, and the substrate holder 20 is not holding any substrates W. This state is maintained until the first (first) substrate W of the next lot is transferred in front of the opening 11 of the container 10.

[0037] During the closed period, the control circuit 90 feedback-controls the opening of the exhaust damper 81 so that the detection value of the pressure sensor 83 becomes equal to the set value. The opening of the exhaust damper 81 during the closed period varies depending on whether or not the substrate holder 20 is holding a substrate W, as shown in Fig. 4. This is because the gas exhaust resistance varies depending on whether or not the substrate holder 20 is holding a substrate W.

[0038] 1, when the substrate holder 20 holds a substrate W, the gas exhaust resistance is greater than when the substrate holder 20 does not hold a substrate W. This is because the substrate W hinders gas exhaust. The variation in exhaust resistance is particularly noticeable when the substrate processing apparatus 1 includes a cup 50 as shown in FIG. 1 and the exhaust duct 70 exhausts gas from inside the cup 50 to outside the container 10.

[0039] In Fig. 4, the first detection value D1 is the detection value of the opening sensor 82 when the substrate holding part 20 is not holding a substrate W during the closed period. Also in Fig. 4, the second detection value D2 is the detection value of the opening sensor 82 when the substrate holding part 20 is holding a substrate W during the closed period. In Fig. 4, D1 and D2 are each acquired, for example, at the end of the closed period. D2 is larger than D1 because the gas exhaust resistance is larger when the substrate holding part 20 is holding a substrate W than when the substrate holding part 20 is not holding a substrate W.

[0040] In this embodiment, when the substrate holding part 20 holds the substrate W during the closed period, the flow rate of gas supplied from the outside to the inside of the container 10 (hereinafter referred to as the supply gas rate) fluctuates. This is because the heating part 40 supplies preheated gas to the peripheral part of the lower surface of the substrate W except for the end of the closed period. At the end of the closed period, the heating part 40 stops supplying gas. Therefore, at the end of the closed period, the opening of the exhaust damper 81 gradually decreases to maintain the pressure inside the container 10 at the set value.

[0041] As with the end of the closed period, the heating unit 40 stops supplying gas during the open period. In order to detect D1 and D2 under the same conditions (air supply volume), D2 may be acquired at the end of the closed period. Note that if the heating unit 40 is not present, that is, if the air supply volume does not fluctuate during the closed period, D2 may be acquired at any time during the closed period as long as the detection value of the opening sensor 82 is stable. Incidentally, D1 may also be acquired at any time during the closed period as long as the detection value of the opening sensor 82 is stable.

[0042] In this embodiment, the control circuit 90 performs offset control during the open period, fixing the opening of the exhaust damper 81 to a value offset by a set amount from the detection value of the opening sensor 82 during the closed period immediately preceding the open period (preferably at the end of the closed period). The offset direction may be a direction increasing the opening as shown by arrow A1 in Fig. 4, or a direction decreasing the opening as shown by arrow A2 in Fig. 4. As will be described in more detail later, offset control can suppress the effects of fluctuations in the exhaust resistance of the gas immediately before and after the open period, thereby suppressing pressure fluctuations inside the container 10.

[0043] The conditions under which the control circuit 90 performs offset control are, for example, when the following (1) and (2) are met: (1) The substrate holding part 20 does not hold a substrate W during a closed period immediately before an open period during which offset control is performed. (2) The substrate holding part 20 holds a substrate W during a closed period immediately after an open period during which offset control is performed. Conditions (1) and (2) are met, for example, when the transport device 2 loads the first substrate W of each lot from the outside to the inside of the container 10.

[0044] When conditions (1) and (2) are met, the gas exhaust resistance is higher immediately after the open period than immediately before the open period. Therefore, when conditions (1) and (2) are met, the offset direction is the direction in which the opening of the exhaust damper 81 is increased as shown by arrow A1 in Fig. 4, that is, the direction in which the flow path of the exhaust duct 70 is opened. This makes it possible to suppress the pressure increase inside the container 10 as shown by arrow B1 in Fig. 4 immediately after the open period.

[0045] The conditions for the control circuit 90 to perform offset control may be that the following (3) and (4) are met: (3) The substrate holding part 20 holds a substrate W during a closed period immediately before an open period during which offset control is performed; (4) The substrate holding part 20 does not hold a substrate W during a closed period immediately after an open period during which offset control is performed. An example of an example of when (3) and (4) are met is when the transport device 2 unloads the last (nth) substrate W of each lot from inside to outside the container 10.

[0046] When conditions (3) and (4) are met, the gas exhaust resistance is lower immediately after the open period than immediately before the open period. Therefore, when conditions (3) and (4) are met, the offset direction is the direction of reducing the opening of the exhaust damper 81 as shown by arrow A2 in Fig. 4, that is, the direction of closing the flow path of the exhaust duct 70. This makes it possible to suppress a pressure drop inside the container 10 as shown by arrow B2 in Fig. 4 immediately after the open period.

[0047] To improve throughput, the unloading of the i-th substrate W from the inside of the container 10 to the outside and the loading of the (i+1)-th substrate W from the outside of the container 10 to the inside of the container 10 in each lot are usually performed during the same open period. Here, i is an integer between 1 and (n-1). When the unloading of the i-th substrate W and the loading of the (i+1)-th substrate W are performed during the same open period, the gas exhaust resistance is approximately the same immediately before and after that open period. Therefore, the opening degree during that open period may be fixed to the second detection value D2 detected by the opening degree sensor 82 during the immediately preceding closed period (preferably at the end of the closed period). In other words, offset control is not required.

[0048] The control circuit 90 calculates a set amount (offset amount) based on the first detection value D1 and the second detection value D2. For example, when the above conditions (1) and (2) are met, the control circuit 90 calculates the set amount (offset amount), for example, as (ΔD / D1×D1′). ΔD is the difference between D1 and D2 (ΔD=|D1−D2|). D1′ is the detection value of the opening sensor 82 in the closed period immediately before the open period for which offset control is performed.

[0049] If D1 and D2 are detected in the first lot, D1' can be detected in the second or subsequent lot. Therefore, the offset control indicated by arrow A1 in FIG. 4 is performed in the second or subsequent lot. Note that D1 and D2 may be detected in the second or subsequent lot as long as they are detected before D1'. If D1 and D2 are detected in the k-th lot, D1' can be detected in the (k+1)-th or subsequent lot.

[0050] When (ΔD / D1×D1′) is used as the set amount, the influence of disturbances such as fluctuations in the suction force of the exhaust source 73 can be reduced compared to when ΔD is used as the set amount. If there is no disturbance, D1 and D1′ will be equal. However, if there is a disturbance, D1 and D1′ will differ. If D1 and D1′ differ, it is preferable to use (ΔD / D1×D1′) as the set amount.

[0051] When the above conditions (3) and (4) are met, the control circuit 90 calculates the set amount (offset amount), for example, (ΔD / D2×D2′). ΔD is the difference between D1 and D2 (ΔD=|D1−D2|). D2′ is the detection value of the opening sensor 82 during the closed period immediately before the open period for which offset control is performed.

[0052] If D1 and D2 are detected in the first lot, D2' can be detected in the first or subsequent lot. Therefore, the offset control indicated by arrow A2 in FIG. 4 is performed in the first or subsequent lot. D1 and D2 may be detected before D2', or may be detected in the second or subsequent lot. If D1 and D2 are detected in the k-th lot, D2' can be detected in the k-th or subsequent lot.

[0053] When (ΔD / D2×D2′) is used as the set amount, the influence of disturbances such as fluctuations in the suction force of the exhaust source 73 can be reduced compared to when ΔD is used as the set amount. If there is no disturbance, D2 and D2′ will be equal. However, if there is a disturbance, D2 and D2′ will differ. If D2 and D2′ differ, it is preferable to use (ΔD / D2×D2′) as the set amount.

[0054] When the substrate processing apparatus 1 includes the switching unit 71, the control circuit 90 may calculate a set amount (offset amount) for each destination of the gas flowing through the exhaust duct 70. Even if the exhaust source 73 of the destination is changed and the suction force of the exhaust source 73 fluctuates, the influence of this can be reduced.

[0055] Although the embodiments of the substrate processing apparatus and substrate processing method according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0056] This application claims priority based on Japanese Patent Application No. 2023-175848 filed with the Japan Patent Office on October 11, 2023, the entire contents of which are incorporated herein by reference.

[0057] REFERENCE SIGNS LIST 1 substrate processing apparatus 10 container 11 opening 12 shutter 20 substrate holder 70 exhaust duct 81 exhaust damper 82 opening sensor 90 control circuit

Claims

1. A substrate processing apparatus comprising: a container; an opening provided in the container through which a substrate passes; a shutter for opening and closing the opening; a substrate holding section for holding the substrate inside the container; an exhaust duct for exhausting gas from inside the container to the outside; an exhaust damper for adjusting the amount of exhaust from the exhaust duct; an opening sensor for detecting the opening of the exhaust damper; and a control circuit for controlling the opening of the exhaust damper during an open period in which the shutter opens the opening and a closed period in which the shutter closes the opening, wherein the control circuit performs offset control for fixing the opening of the exhaust damper during the open period to a value offset by a set amount from the detection value of the opening sensor during the closed period immediately preceding the open period.

2. The substrate processing apparatus of claim 1, wherein the condition for the control circuit to perform the offset control is that the substrate holding portion does not hold the substrate during the closed period immediately preceding the open period during which the offset control is performed, and that the substrate holding portion holds the substrate during the closed period immediately following the open period during which the offset control is performed.

3. The substrate processing apparatus of claim 1, wherein the condition for the control circuit to perform the offset control is that the substrate holding portion holds the substrate during the closed period immediately preceding the open period during which the offset control is performed, and that the substrate holding portion does not hold the substrate during the closed period immediately following the open period during which the offset control is performed.

4. The substrate processing apparatus of claim 1, wherein the control circuit calculates the set amount based on a first detection value which is the detection value of the opening sensor when the substrate holding portion is not holding the substrate during the closed period, and a second detection value which is the detection value of the opening sensor when the substrate holding portion is holding the substrate during the closed period.

5. The substrate processing apparatus of claim 4, wherein the condition under which the control circuit performs the offset control is that the substrate holding part does not hold the substrate during the closed period immediately preceding the open period during which the offset control is performed, and that the substrate holding part holds the substrate during the closed period immediately preceding the open period during which the offset control is performed, and the control circuit calculates as the set amount the product (ΔD / D1×D1′) of the ratio (ΔD / D1) of the difference (ΔD: ΔD=|D1-D2|) between the first detection value (D1) and the second detection value (D2) to the first detection value (D1) and the detection value (D1') of the opening sensor during the closed period immediately preceding the open period during which the offset control is performed.

6. The substrate processing apparatus of claim 4, wherein the condition under which the control circuit performs the offset control is that the substrate holding part holds the substrate during the closed period immediately preceding the open period during which the offset control is performed, and that the substrate holding part does not hold the substrate during the closed period immediately preceding the open period during which the offset control is performed, and the control circuit calculates as the set amount the product (ΔD / D2×D2′) of the ratio (ΔD / D2) of the difference (ΔD: ΔD=|D1-D2|) between the first detection value (D1) and the second detection value (D2) to the second detection value (D2) and the detection value (D2') of the opening sensor during the closed period immediately preceding the open period during which the offset control is performed.

7. The substrate processing apparatus according to claim 1, further comprising a switching unit that switches the destination of the gas flowing through the exhaust duct depending on the type of gas flowing through the exhaust duct, and the control circuit calculates the set amount for each of the destinations.

8. A substrate processing method comprising processing a substrate using a substrate processing apparatus, the substrate processing apparatus comprising a container, an opening provided in the container through which a substrate passes, a shutter for opening and closing the opening, a substrate holding part for holding the substrate inside the container, an exhaust duct for exhausting gas from inside the container to the outside, an exhaust damper for adjusting the amount of exhaust through the exhaust duct, and an opening sensor for detecting an opening of the exhaust damper, the substrate processing method comprising controlling an opening of the exhaust damper during each of an open period and a closed period of the opening, and performing offset control for fixing the opening of the exhaust damper to a value offset by a set amount from a detection value of the opening sensor during the closed period immediately preceding the open period.

9. A substrate processing method as described in claim 8, wherein the condition for performing the offset control is that the substrate holding part does not hold the substrate during the closed period immediately preceding the open period during which the offset control is performed, and that the substrate holding part holds the substrate during the closed period immediately preceding the open period during which the offset control is performed.

10. A substrate processing method as described in claim 8, wherein the condition for performing the offset control is that the substrate holding portion holds the substrate during the closed period immediately preceding the open period during which the offset control is performed, and that the substrate holding portion does not hold the substrate during the closed period immediately following the open period during which the offset control is performed.

11. The substrate processing method of claim 8, further comprising calculating the set amount based on a first detection value which is a detection value of the opening sensor when the substrate holding portion is not holding the substrate during the closed period, and a second detection value which is a detection value of the opening sensor when the substrate holding portion is holding the substrate during the closed period.

12. The substrate processing method of claim 11, wherein a condition for performing the offset control is that the substrate holding part does not hold the substrate during the closed period immediately preceding the open period in which the offset control is performed, and that the substrate holding part holds the substrate during the closed period immediately preceding the open period in which the offset control is performed, and the substrate processing method comprises calculating, as the set amount, a product (ΔD / D1×D1′) of a ratio (ΔD / D1) of a difference (ΔD: ΔD=|D1-D2|) between the first detection value (D1) and the second detection value (D2) to the first detection value (D1) and a detection value (D1') of the opening sensor during the closed period immediately preceding the open period in which the offset control is performed.

13. The substrate processing method of claim 11, wherein a condition for performing the offset control is that the substrate holding part holds the substrate during the closed period immediately preceding the open period during which the offset control is performed, and that the substrate holding part does not hold the substrate during the closed period immediately preceding the open period during which the offset control is performed, and the substrate processing method comprises calculating, as the set amount, a product (ΔD / D2×D2′) of a ratio (ΔD / D2) of a difference (ΔD: ΔD=|D1-D2|) between the first detection value (D1) and the second detection value (D2) to the second detection value (D2), and a detection value (D2') of the opening sensor during the closed period immediately preceding the open period during which the offset control is performed.

14. The substrate processing method of claim 8, wherein the substrate processing apparatus is provided with a switching unit that switches the destination of the gas flowing through the exhaust duct depending on the type of gas flowing through the exhaust duct, and the substrate processing method includes calculating the set amount for each destination.